CA1311923C - Gasification process and apparatus - Google Patents

Abstract

ABSTRACT

The invention provides a process and apparatus for the gasification of solid or solid and liquid organic, i.e.
carbonaceous matter by partial combustion with a gasifying medium comprising oxygen, or oxygen and steam or oxygen and carbon dioxide, wherein the organic matter is first subjected to partial combustion and pyrolysis at a temperature within the range of from about 400°C upwards, but below the ash fusion or softening temperature of the organic matter in a first gasification treatment, whilst being supported above a fire grate or equivalent partition means in the presence of substochiometrical amounts of oxygen introduced with the gasifying medium. Thereafter the gases generated in the first gasification treatment are subjected to thermal cracking in at least one further heat treatment again in the presence of oxygen, the further heat treatment being carried out either avoiding direct contact with ash or ash-containing residue of the organic matter formed in the first gasification treatment, also in the presence of oxygen, or, provided the ash of the organic matter has a melting or softening temperature above the temperature of the further heat treatment, in an embers bed, including said ash, confined in a constricted passage supported by the same or yet a further fire grate defining at least one variable gap constituting the lower limit of the passage and controlling the rate of gradual downwards travel of the embers bed.

Description

The present invention relates to a process and apparatus for the gasification of solid or solid and liquid organic, i.e.
carbonaceous matter by partial combustion with a gasifying medium comprising oxygen or oxygen and steam or oxygen and carbon dioxide. The invention can be applied to a large variety of different uses, including waste dlsposal (solid as well as liquid by incineration with or without utilisation of the gas and sensible heat generated by the process, fuel gas production (ranging from lean producer gas to higher grade fuel gases).useful for heating purposes, steam raising and the like as well as for fuelling internal combustion engines ~diesel engines, spark ignition engines and gas turbines) and for the manufacture of varioùs grades of synthesis gas.
lS According to its main aspects the invention relates to improvements and/or modifications of the invention desc~ibed and claimed in Canadian patent ap411Lation No.~073,7~Inter alia the invention can be applied to a very complete gasification of the gasifiable content of a wide variety of carbonaceous materials, including waste materials such as sawdust and other sawmill wastes, forestry wastes, agricultureal wastes, domestic and other refuse, various industrial wastes, but also various grades of solid fossilised fuels, ranging from peat through lignite, oil shale, tar sand to black coal. It is a feature of the invention that effective pyrolysis with partial combustion of such materials can be achieved at relatively modest temperatures, whereby it is often possible to avoid or mitigate ash fusion or ash softening problems as well as certain heavy metal volatilisation problems sometimes ex~perienced with more conventional gasification processes operating at higher temperaturqs.
Waste incineration processes of the kind to which ce~r~tai~n aspects of the invention relate are known; for example~from Maschinenmarkt, WUrzburg, 81 (1975) 69, page 1923, a process is known referred to as high temperature . .

: ~ .
c . . ,...., ~. "
. ~., ~.~.. ...... .

731 lq~3 process according to which refuse is incinerated and in whicll the combustion of the pyrolysis gases takes place in a separate coml)ustion chamber. Also from DE-PS 26 04 408 a process is known in which the gases arising during the pyrolysis of waste materials are supplied to a combustion chamber, there to be combusted.
In the combustion of flue gases it is desirable for these to be burnt off as completely as possible, even when considering only the generation of residual gases friendly to the environment, and particularly, if the sensible heat arising from the combustion of the gases is desirable in order to improve the energy balance. However, the complete combustion of the flue gases in which the aromatics in the flue gases are converted, is possible only at relatively high temperatures in the combustion chamber which must be higher than 1000C. Such high temperatures are indeed possible also in conducting the known processes, e.g.
according to DE-PS 26 04 409. However, to set up such high temperatures, results in difficulties in the known processes due to the fact that the melting of the ash, whilst in the combustion chamber, cannot be avoided. This results in undesirable deposit formations in the combustion chamber and thus in faulty operation.
A need therefore exists in the art to provide a process of the type referred to in the introduction which permits as complete a combustion of the gases as possible without operating problems.
Liquid wastes which can be disposed of in accordance with the invention include for example lacquer sludges which are left behind as soiled residual liquids after the application or spraying of lacquers onto workpieces to l)e painted. In lacquer workshops and spray painting shops such sludges are formed as a waste material in considerable quantities. Lacquer residues w~ich cannot be further utilised are, however, also unavoidable in the manufacture of lacquers. These include for example reject batches.

:

Lacquer sludges - optionally after having been concentrated - are dumped on special dumping sites. This not only involves expense. For such dumping moreover only a small number of dumping sites are available which as time progresses are becoming increasingly scarce due to extensive utilisation.
Similar difficulties are also caused by paint and solvent wastes.
It is also known in double or multiple stage gasification of the down draft type for the gas formed in the first gasification stage to pass through one or more subsequent high temperature zones in the subsequent one or more gasification stages. However, in that case the maxirnum temperatures of all the high temperature zones are limited by the restraints imposed by the ash fusion or softening temperature of the solid carbonaceous matter.
There exists a need for a gasification process of the type indicated above which permits the cracking of tars and tar oils contained in the gas emerging from the first high temperature zone in a second high temperature zone, the temperature of which is not limited by the gas fusion or softening temperature of the solid carbonaceous matter from which the gas was formed and wherein cracking of the tars and tar oils and cleaning of the gas preferably proceeds as far as possible not at the expense of gas already forrned.
The gasification of many solid fuels, in particular coal is generally carried out with greater or lesser additions of water, usually in the form of steam, to the gasifying medium in order to promote the complete gasification of the solid carbonaceous matter and to increase the hydrogen content of the gas, some of which hydrogen may be in tne forM of hydrocarbons such as methane.
In such processes it is important to regulate the rate at which water is introduced into the gasifier.
35The present invention proposes a method and means for regulating the feed rate of water vapour to the gasiPier in ... .

9 ~ ~
a particularly simple manner. At the same time the invention can be used to permit parts of the gasifier apparatus exposed to high temperatures to be constructed of materials of relatively modest temperature resistance.
In accordance with the present invention there is provided a process for the gasification of solid or solid and liquid organic, i.e. carbonaceous matter by partial combustion with a gasifying medium comprising oxygen or oxygen and steam or oxygen and carbon dioxide, wherein the 10 organic matter is first subjected to partial combustion and pyrolysis at a temperature within the range of from about 400C upwards, but below the ash fusion or softening temperature of the organic matter in a first gasification treatment, whilst being supported above a fire grate or 15 equivalent partition means in the presence of substochiometrical amounts of oxygen introduced with the gasifying medium, whereafter gases generated in the first gasification treatment are subjected to thermal cracking in at least one further heat treatment, again in the presence 20 of oxygen, the further heat treatment being carried out either whilst avoiding direct contact with the ash or ash containing residue of the organ~c matter formed in the first gasification treatment, also in the presence of oxygen - or, provided the ash of the organic matter has a melting or 25 softening temperature above the temperature of the further heat treatment, in an embers bed including said ash, confined in a constricted passage supported by the same or yet a further fire grate defining at least one variable gap constituting the lower limits of the passage and controlling 30 the rate of gradual downwards travel of the embers bed.
In the latter modification it is due to the constricted passage defining the outlines of the embers bed and leading towards a relatively narrow gap of variable width that the ~pyrol~sis gases are subjected to particularly intimate 35 contact with the embers bed to resultin cracking of tar and oil constituents still contained in the gas. The gap is - ~ ~

1~1 19~3 variable and by alternating the increasing and decreasing the size of the gap from time to time, it is possible to regu~ate the rate of downward travel of the embers beds and thereby the completeness to which combustible matter of the 5 embers bed is utilised before the ash or ash containing residue of the organic matter is discharged through the gap into an ash pit or the like for eventual disposal.
One embodiment according to which the gases may be subjected to a further heat treatment may be carried out in 10 that gases formed in the first gasification treatrnent are recycled to where the first gasification treatment takes place, thereby being subjected to thermal -cracking by further heat treatment in the presence of oxygen introduced with the gasifying medium.
According to preferred embodiments of the invention, the partial combustion and pyrolysis takes place under downdraft conditions in a bed subjected to mechanical internal reconstitution by back and forth agitation in predominantly horizontal direction, more particularly in an 20 embodiment, wherein simultaneously with the back and forth agitation the size of a variable gap constituting the lower limit of a passage through which the bed travels gradually downward is increased and decreased, thereby regulating the rate at which the bed travels, preferably wherein the 25 mechanical agitation is brought about by back and forth tilting about a horizontal axis of an agitating member.
It is particularly preferred that simultaneously with the back and forth horizontal agitation the bed is subjected to an up and down displacement action. Preferab7y the 30 agitating member is also used for feeding gasifying medium into th bed.
Advantageously the agitating member projects upwardly from a fire grate member defining the lower limit of the bed, mounted pivotally about a substantially horizontal axis 35 and comprising on both sides of the axis upwardly directed, downwardly sloping flanking surfaces which carry the bed, .:. .. ,:

:
. ~

131 19~

tne lower edges of the flanking surfaces each defining one side of a gap controlling the passage of bed material, the width of the gap being varied when the fire grate member is tilted back and forth, thereby subjecting the bed to the 5 horizontal agitation and the up and down displacement action.
What has been described above in relation to the partial combustion and pyrolysis step, is preferably also applied in the same or an analogous manner to the further heat treatment when carried out under downdraft conditions 10 in a bed subjected to mechanical internal reconstition by back and forth agitation in predominantly horizontal direction.
A particular embodiment which is considered particularly useful for the gasification of relatively 15 unreactive carbonaceous matter such as coal, and in particular black coal the partial combustion and pyrolysis takes place under downdraft conditions in a first bed supported by a fire grate member defining the lower limit of the bed, mounted pivotally about a substantially horizontal 20 axis and comprising on both sides of the axis upwardly directed, downwardly sloping flanking surfaces which carry the bed, the lower edges of the flanking surfces each defining one side of a gap controlling the passage of bed material, the width of the gap being varied when the fire 25 grate member is tilted back and forth, and wherein the bed material discharged from the first bed drops onto and forms a second bed underneath the first bed, supported in substantially the same or similar manner as the first bed, the gas generated in the first bed in the first gasification 30 treatment leaving the first bed through the gaps at the bottom of the first bed being passed under downdraft conditions through the second bed for further heat treatment.
Preferably at least one of the beds is subjected to 35 mechanical internal reconstitution by the back a.nd forth agitation action of an agitating ~ember projecting upwardly : . 6 ., .

.

from the fire grate member supporting the bed.
Advantageously at least one of the beds is supplied with gasifying medium or steam or both through a feed member projecting upwardly from the apex of the fire grate member 5 supporting the bed.
A different embodiment according to the invention is provided wherein a further heat treatment of the gas takes place -substantially out of direct contact with the ash or ash-containing residue formed in the first gasification 10 treatment, which comprises passing the gases emerging from the first gasification treatment into a combustion chamber and there adding to the gas further oxygen or oxygen-containing gas in an amount sufficient to raise the temperature of the gas by combustion reactions above the 15 temperature of the first gasification to bring about thermal cracking of crackable compounds of the gas.
Preferably air or oxygen is first added in substochiometrical proportions whereafter the hot gases are led into a duct where further air or oxygen is added to 20 complete the combustion of the gas. In that embodiment generally the sensible heat of the combustion gases is used for heating purposes.
In the lastmentioned embodiment the gases from within the combustion chamber to its outlet or outlets are 25 conducted separately, fresh air being admixed to the separately conducted gases. The separate conductance of the gases permits - in conjuntion with the easily controllable feeding of fresh air to the separately conducted gases - to set up the temperatures required for the complete combustion 30 within a defined region. The remaining region of the combustion chamber may then be kept at a lower temperature level, whereby the adverse effect of high ternperature on the combustion chamber walls may be reduced and other drawbacks such as for example, the melting of the ash, can be avoided.
35 This applies particularly to an advantageous embodiment of the process according to the invention in which the gases ._ ,., .. _ .. , .. , .. . ..... _. . _ _ _ _ ., - . :
- : ' '. ' ' ''''' ' ,' - . . ~ .

~ - 131 1~2~

are conducted separately starting from the centre of the combustion chamber or respectively passing through the centre of the combustion chamber.
The separate conductance of the gases furthermore makes 5 possible particularly favourable starting-up conditions for the combustion chamber. The reason is that if the gases are ignited in the defined region of separate conductance, this region can be raised very rapidly to the temperature of about 800C required for the formation of clean residual 10 gases.
- A particularly advantageous modification of the process according to the invention resides in that the gases fed into the combustion chamber are supplied with fresh air in sub-stochiometrical ratio and additionally thereto fresh 15 air is supplied to the conducted gases in a ratio which is at least stochiometrical. By this expedient - the appropriate proportioning of the amounts of fresh air - it is possible in an optimal manner to adjust the desired high temperatures in the defined region of the separately 20 conducted gases whilst lower temperatures are maintained in the remaining region of the combustion chamber.
The invention also provides another type of process modification wherein the further heat treatment takes place out of direct contact with the ash or ash-containing residue 25 of the organic matter and which comprises maintaining a second high temperature zone, separated and rernote from the first gasification zone and maintained at a temperature sufficiently high for substantially complete cracking oF
tars and tar oils, wherein the second high temperature zone 30 comprises an embers bed formed by a solid carbonaceous fuel producing substantially no fused or softened ash at that temperature. Such process may for example be applied to the higll temperature gasification of solid carbonaceous matter by partial combustion.
This procedure may also be applied advantageously to the gasification of liquid wastes comprising organic . - j . .

^-- 131 1923 cor,lponents, ~ilerein the liquid wastes are applied onto an embers bed to convert the liquid wastes into gaseous products, the gaseous products being withdrawn through the embers bed and in the course thereof being so heated in the 5 embers bed that high molecular mass organic components in the gas are cracked, the withdrawn gas mixture cleared off ash particles, serving as a fuel gas.
The term "embers" as herein employed is intended to denote glowing particles of carbonaceous matter, e.g. char 10 or coal of greater or lesser size and includes such matter in an incandescent state of greater or lesser intensity.
The liquid waste is applied onto an embers bed at a controlled rate such that the liquid waste is evaporated.
Gaseous products and solid residual components are formed.
l5 The gaseous products are drawn through the embers bed, thereby being so heated that high molecular weight organic components in the gas are cracked. For that purpose the embers bed in accordance with a further preferred feature of the invention comprises at least one temperature zone 20 having a temperature in the range of from 800C upwards, e.g, 800 - 1000C through which the gaseous products have to pass. A readily ignitable gas mixture comprising low molecular weight gas components such as H2, C0, CH4 is formed. The gas mixture withdrawn from the embers bed can 25 therefore be utilised as a fuel gas for energy generation, optionally with the introduction of additional oxygen. The fuel gas is already cleaned to a substantial extent of the solid residual components formed during the conversion of the liquid waste. The residual components form part of the 30 embers bed and are withdrawn from the embers bed in the form of ash.
It is advantageous to pass the gaseous product, preferably after a first separation of ash particles through a cracking and cleaning stage following thereafter having a 35 temperature which is preferably higher than that of the aforesaid embers bed, e.g. between 900 and 1500-C, say : ~ :

:, :

1000C. In that stage a cracking of residual high molecular weight organic components still contained in the gas mixture being discharged takes place. In addition the fuel gas is cleaned of dust particles which are still entrained. This 5 takes place in an embers bed through which the gaseous products pass. From the cracking and cleaning stage a fuel gas emerges which has a low tar and oil content.
For forming the embers bed degassed high carbon material, for example coke or charcoal is used. In the lO first embers bed it is possible in addition to employ grinding mill balls which cause the comminution of the material particles which form the embers bed.
By spraying the waste liquid over the embers bed of the first stage and by its distribution in small droplets 15 evaporation is facilitated and a uniform distribution in the shaft space above the embers bed is attained.
As already indicated, a particular aspect of the invention provides a process for the high temperature gasification of solid carbonaceous matter by partial 20 combustion with a gasifying medium comprising oxygen in a first high temperature zone to form a combustible gas followed by passing the combustible gas through a second high temperature zone, separated and remote from the first zone and rnaintained at a temperature sufficiently high for 25 substantially complete cracking of tars and tar oils, wherein the second high temperature zone comprises àn embers bed formed by a solid carbonaceous fuel producing substantially no fused or softened ash at that temperature.
~ ~Accordingly it is now possible to subject to the high 30 temperature gasification in the first high temperature zone a solid carbonaceous matter which has an ash fusion or softening temperature below the temperature maintained in the second high temperature zone, the temperature of the first high temperature zone being maintained at a level to 35 gasify the carbonaceous matter without fusing or softening the ash. This means that the gasification of the solid ; ;
.. ,.,: 10 .

carbonaceous matter can proceed at a relatively low temperature from 450 upwards, e.g. in the range of 600 to lOOO~C, more particularly frorn 700 to 900 and in any event below the ash fusing or softening temperature of the solid 5 carbonaceous matter. This also means that relatively low quality solid carbonaceous matter having a relatively low ash fusion or softening temperature can be gasified without ash fusion or ash agglomeration problems occurring.
Also it is possible to gasify materials containing lO heavy metals whilst avoiding wholly or in part the volatilisation of such heavy metals. This can be important in two contexts. Firstly it may be desired to recover the heavy metals in the ash. Secondly, if the heavy metals are toxic their volatilisation may be environmentally undesirable.
The second high temperature zone is operated at temperatures from 800~C upwards, e.g. from 900 to 1300C, preferably at 1000 - 1200C. ~
The second high temperature zone may be operated under down-draft conditions, which means that any higher molecular 20 weight components such as tars or tar oils which may be formed in the higher region of the fuel bed which forms the second high temperature zone will be conducted through the regions of highest temperature of the second high temperature zone and be subjected to cracking as well.
The solid carbonaceous fuel used for producing the second high temperature zone is selected from those producing substant~ally no ash which is fused or softened at the temperature of the second high temperature zone. In general this will be a material having an ash fusion or 30 softening temperature substantially higher than that of the solid carbonaceous matter subjected to gasification in the first high temperature zone.
This means that the second high temperature zone can be operated under process conditions which would have resulted 35 in ash fusion and a~glomeration problems if the solid carbonaceous matter present in the first high temperature ,. 11 , , .

... , . ~ . . .. ~ , . . _ . . .. . .... . . .

~ . .... .

-- 1 31 1 9~3 zone had been present there as well. The separation of the first high temperature zone from the second high temperature zone avoids these problems, because the ash from the first zone can thus be withdrawn separately without entering the 5 second zone.
The terms "first" and "second" zone are intended to include the case where either or both of these zones are in their-turn subdivided into a succession of zones. For example, the gasification of the solid carbonaceous matter lO passing through the first zone may in fact proceed in more than one stage, provided the ash fusion or softening temperature is not reached in any of these stages.
If the solid fuel in the second high temperature zone is substantially free of tar or oil-yielding volatiles, e.g.
15 coke or charcoal, it is possible to operate the second high temperature zone not necessarily under down-draft conditions, but also optionally under updraft conditions, without creating additional tar and tar oil problems.
This can have the advantage that higher temperatures 20 may be attained without excessively exposing the fire grate to heat.
The gasification of the solid carbonaceous matter in the first high temperature zone can be carried out under any suitable gasification conditions, including fluidised bed or 25 circulatory fluidised conditions, although a solid bed gasification is preferred. Preferably the first high temperature zone is operated under down-draft conditions and ; the first high temperature zone is provided by an embers bed formed by the solid carbonaceo~s matter.
The solid carbonaceous matter may for example be brown coal or black coal. The process may for example be conducted using high ash, high volatile duff coal which is a very cheap material, serving as the solid carbonaceous matter for the gasification. The solid carbonaceous matter 35 may comprise waste coal or low grade coal having an ash content, e.g. in excess of 25~ by mass based on dry matter, : : :
"i , e.g. as high as 50% ash. However, the process can also be applied to the gasification of other low grade fossilised solid fuels, e.g. so-called oil shale or tar sands. Thus the process can be applied to the gasification of waste 5 materials from coal mines which at present are dumped, because they are below marketable grade. Besides the energy content of such materials being irretrievably lost by dumping, these dumps constitute an environmental hazard.
These dumps are subject to spontaneous ignition and then 10 give rise to noxious fumes and smoke.
According to a further embodiment, the solid carbonaceous matter comprises domestic garbage, e.g.
introduced in pel~et form or other suitable compacted particle form. The gasification of such materials is 15 problematic because of the low ash fusion temperature of garbage.
The invention may also be applied to the gasification of solid carbonaceous matter comprising bagasse or wood, e.g. bagasse which has been pelletised and dried, e.g.
20 according to technology which is now in commercial use in Brazil. By passing the gas produced in the first high temperature zone by the gasification of bagasse or wood through a second high temperature zone maintained at a sufficiently high temperature, e.g. fuelled with charcoal, 25 it is possible to produce fuel 9ases which require relatively little further cleaning in order to be usable for the fuelling of internal combustion engines. It is also possible to avoid or mitigate tar formation problems which arise from the gasification of biomass having a relatively 30 high moisture content. This is particularly so, if in the second high temperature zone a fuel is used which requires some moisture for optimum gasification.
The solid fuel used in the second high temperature zone may for example bç anthracite or coke having a high ash 35 softening temperature, or charcoal. These fuels are usually more expensive than the solid carbonaceous matter gasified : ', ,,, .~,.. i ~ ,,,. .. . :

.~

in the first high temperature zone. However, the consumption of the more expensive solid fuel is generally very much less than the consumption of solid carbonaceous matter in the first high temperature zone. For example, S generally the solid fuel consumed in the second high temperature zone constitutes in terms of fuel value less than half the amount of solid carbonaceous matter gasified in the first high temperature zone, e.g. Iess than 30~ and may be as little as lO~. This may be achieved by lO restricting the dimensions of the second high temperature zon~ to smaller dimensions than those of the first high temperature zone. Moreover, the admission or feeding of gasification medium, in particular air or oxygen or oxygen-containing gases is so restricted so that the required high15 ternperature is maintained, preferably in a concentrated region whilst fuel consumption is restricted.
It is furthermore possible to include in the second high temperature zone substances which catalise the cracking of tars and tar oils and other substances, e.g. ammonia.
20The, fuel gas produced according to the invention may for example be cooled and - if necessary after further cleaning - be used to power an internal combustion engine.
For example, the process may be used to produce gaseous fuel for diesel generators or gas turbines or generators powered 25 by spark ign~tion engines. The practising of the process is not limited to any particular scale. It can be applied to relatively small power generating plant, or to relatively large plant, e.g. to supply peak power requirements. In this context it is an advantage that the process can be 30 adapted for intermittent operation, since the embe.rs bed of gasification furnaces as used in the process can be kept "dormant" for relatively long periods, ready for a ;resumption of the gasification by the renewed introduction ~ of gasification medium at relatively short notice..
~ The process may also be applied to the powering of mobile units, e.g. for powering the diesel engines of ships.

l4 ~ .
.: . . . , -:

However, the invention may also be applied to the powering of smaller mobile equipment, e.g. tractors or trucks. In that case the solid carbonaceous matter may for example be wood or bagasse pellets whilst the second high temperature 5 zone is fuelled with relatively small amounts of charcoal, thereby minimising the tar and tar oil content of the gas.
The process may also be applied to the production of gas for industrial or domestic heating purposes or to the production of synthesis gas.
The gasification may be carried out at substantially atmospheric pressure or at elevated pressure in accordance with generally known principles. Depending on the purpose for which the gas is to be used, the gasifying medium comprising oxygen may be air or air enriched with oxygen or 15 pure oxygen. Air enriched with oxygen or pure oxygen may for example be introduced into the second high temperature zone where generally a high temperature is desirable.
However, in order to promote high temperatures, particularly in the second high temperature zone, it is also possible to 20 preheat the gasifying medium, e.g. air before its introduction into the high temperature zone. This may for example be done by heat exchange to recover the sensible heat of the gas produced.
It is also possible to introduce water into the 25 gasification medium and/or one of the embers beds, e.g. at a locality in or preceding the first embers bed. Such introduction of water is particularly desirable if the solid carbonaceous matter is coal of relatively low moisture content. The water may be introduced in the forrn of steam, 30 such steam being for example generated and/or heated using sensible heat generated by the gasification process.
As mentioned above, it is desirable in certain cases for steam to be included in the gasifying medium or to be injected into the bed of solid carbonaceous matter being 35 gasified. According to one aspect of the present invention, such a process is provided wherein the water is introduced 131 lq23 in the form of steam into the gasification chamber from a water jacket means forming-part of the confining outlines of the gasifier furnace in contact with an incandescent region of the furnace interior, the rate of steam introduction 5 being controlled by controlling the water level in the water jacket means.
According to one embodiment, the water jacket means form part of the outer upright confining outlines of the incandescent region. According to another embodiment, the 10 water jacket means form part of fire grate means of the gasifier.
The aforegoing two possibilities may of course be combined in a single process or apparatus.
The invention also provides apparatus for carrying o~t 15 the various process modifications described in the aforegoing.
Thus, for carrying out that process in which the gases from the first gasification zone are subjected to combustion out of contact with the ash combustion chamber an apparatus 20 is suitable in which at least one gas duct comprising one or more apertures leading into the combustion chamber, is provided passing through or starting from the interior of the combustion chamber and the one end of which constitutes the outlet of the combustion chamber or is connected 25 thereto, and which is adapted to be connected ta a fresh air feedline. The gas duct in this context is made advantageously of refractory material such as ceramic or heat-resistant steel.
An advantageous embodiment of the combustion chamber 30 comprises the feature that the gas duct passes through the centre of the combustion chamber or starts from the centre of the combustion chamber.
A simple embodiment of the combustion chamber according to the invention provides for a gas duct comprising a pipe 35 having lateral apertures. In this context the lateral apertures may be directed towards the upper part, the sides .

,.~ ,, ~: :

, , . ~

-`` 131 1923 of t~e combustion chamber or even to the ash discharge means. Preferably the lateral apertures are directed towards the ash discharge means in order to avoid as far as possible, an entry of fly ash or other dust particles into 5 the gas duct. In this context it is advantageous for the gas duct to pass through the interior of the combustion chamber and for the fresh air feedline to be adapted to be connected to that end of the gas duct which is opposite to the outlet of the combustion chamber. However, the fresh lO air feed may proceed also, for example, through a fresh air feedline projecting into the gas duct. The resulting selection of the fresh air inlet position provides the possibility to influence the combustion procedures in the combustion chamber or in the gas duct respectively, not only 15 by controlling the amounts of fresh air, but also by the selection of the position of introduction of the fresh air.
In determining the feed position regard may be had for example, to the residence period of the gases in that portion of the gas duct which succeeds the feed position.
The combustion chamber according to the invention may be applied in an advantageous manner to a combustion plant for the combustion of combustible material in which the combustible material is first pyrolised in a chamber provided therefore and the flue gases resulting from the 25 pyrolysis are fed to the combustion chamber. The employment of the combustion chamber according to the invention wlll then permit a particularly effective control of the combustion processes taking place in the combustion chamber.
~ epending on the selection of the manner of feeding 30 fresh air into the gas duct, the separate conductance of the gases into the combustion chamber combined with an intense combllstion of the gases, results in a concentrated flame jet extending beyond the region of the combustion chamber. In order to attain a flame jet extending, if possible beyond 35 tlle combustion chamber, it may thus be advantageous to feed the fresh air to the separately conducted gases only close , ~

~ .................................................................. .

to the outlet of the combustion chamber or optionally even outside the combustion chamber. In that case the combustion chamber according to the invention may be employed particularly advantageously in the context of a combustion 5 plant for the combustion of combustible material in which the combustion chamber is succeeded by a means for utilising the sensible heat. Thus, for example, the combustion chamber may be succeeded by a boiler of a heating plant, the flame jet emerging from the gas duct of the combustion 10 chamber being directed onto the heat exchanger o~ the boiler.
For those process embodiments requiring steam injection the invention also provides a gasification apparatus comprising a furnace adapted to hold solid carbonaceous 15 matter to be gasified, including at least a region thereof in a more or less intense incandescent state, comprising a water jacket device or devices bordering the region and forming a confining outline thereof, a level regulating device for controlling the level of water maintained in the 20 jacket and ducts or passage means for releasing steam generated ~n the jacket into the interior of the furnace.
The level regulating device may for example comprise a float valve, various suitable designs of which are known per se and therefore require no description.
In accordance with one preferred embodiment the water ~acket device forms upright walls of the furnace. According to a further preferred embodiment, the features of which may be combined with the previous embodiment, the water jacket device is incorporated in a fire grate devtce of the 30-furnace.
For the gasifiction of liquid wastes the invention also provides a shaft furnace for carrying out the process of the invention comprising a) a shaft space adapted to be closed in a gas-tight manner in its upper region and limited in a downward direction by a grate serving to support an embers bed .. . , . ~ ,. ...

131 lq23 to be formed in the shaft space and provided in a rotatable or pivotal fashion in the shaft in such a manner that between the margin of the grate and the wall of the shaft a gap acting as a passage is left for ash particles to be withdrawn under the action of gravity from the embers bed, b) a feed means for a liquid waste material to be applied onto the embers bed and comprising organic components and entering into the shaft space above the embers bed, c) a gas duct for introducing an oxidising agent into the embers bed, and d) a withdrawal means connected below the grate for the gas mixture formed in the embers bed by evaporation and gasification of the liquid waste.
The shaft furnace comprises a shaft space which in its upper region is adapted to be closed in a gas-tight manner and which in a downward direction is limited by a grate serving for supporting an embers bed. The embers bed is 20 maintained by charging solid fuel from above. The shaft furnace is preferably operated under down-draft conditions.
The grate is rotatable or pivotal in the shaft and so provided that between its edge and the shaft wall a gap for the passage therethrough of ash particles remains which are 25 discharged from the embers bed under the action of gravity.
Above the embers bed a feed duct enters into the shaft for a liquid waste material to be applied onto the embers bed and comprising the organic components. A gas duct leading into the shaft serves for feeding an oxidising agent into the 30 embers bed. The gas mixture formed in the embers bed due to the evaporation and gasification of the liquid waste is withdrawn in the lower region of the shaft furnace. The withdrawal means required therefore is connected below the grate. The gas mixture withdrawn can be employed directly 35 for heat generation as a fuel gas. The embers bed has a temperature zone at a teMperature in the range between 800 .,, 19 ~: !

-and 1000C, or somewhat higher or lower, depending on the fuel.
A gas mixture containing very little or no tar residues is generated by adding in series a second cracking and 5 cleaning stage. The second stage in the same manner as the shaft furnace comprises an embers bed. The embers bed has a temperature e.g. of 900 to 1000C. The second stage is operated under updraft conditions, i.e. the gaseous products withdrawn from the shaft furnace flow through the 10 embers bed in countercurrent to the embers bed material which under the action of gravity moves downwardly in the cracking reactor. In the embers bed the high molecular weight organic gas components still contained in the gas mixture are cracked. In addition fine ash particles 15 entrained in the gas are retained.
The embers beds are composed of degassed high carbon material, for example of coke or charcoal. A comminution action is attained by the addition of grinding mill balls which are added to the embers bed in the shaft furnace.
According to a different aspect of the invention the apparatus according to the invention may also be defined as an apparatus for the gasification of liquid wastes comprising organic components, comprising two furnaces, the first one being adapted to maintain a first charge of 25 glowing solid embers and comprising means for feeding liquid waste material comprising organic wastes to that charge of embers and the ~econd furnace being adapted to maintain a high ternperature second charge of embers substantially free of volatiles, and further comprising means for feeding gas 30 from underneath the first charge of embers through the second charge of embers to a withdrawal locality.
Preferably the first furnace comprises a grate adapted to support a solid fuel and first embers bed under down draft conditlons.
Preferably the second furnace is adapted to support the second charge of embers in the form of a second embers ' bed and to be operated under updraft conditions.
According to a specific aspect of the present invention, there is provided a process for the high temperature gasification of solid carbonaceous matter by 5 partial combustion with a gasifying medium comprising oxygen in a first high temperature zone to form a combustible gas followed by passing the combustible gas through a second high temperature zone, separated and remote from the first zone and maintained at a temperature sùfficiently high for lO substantially complete cracking of tars and tar oils, wherein the second high temperature zone comprises an embers bed formed by a solid carbonaceous fuel producing substantially no fused or softened ash at that temperature.
According to a further aspect of the invention there is 15 provided an apparatus for carrying out the process as set out above comprising two gasification furnaces connected in series and wherein the first gasification furnace comprises a duct for passing gas generated in the first furnace to the top of the second gasification furnace which is of the down 20 draft type. Preferably the first furnace is also of the down draft type, the reason being that any volatiles including tars and tar oils generated in the second gasification furnace will also pass through the high temperature zone in the second furnace, there to be 25 subjected to cracking into low molecular mass constituents.
The apparatus may comprise means for injecting water or steam into eitller or both of the reactors. Preferably the means for injecting water or steam is in the first reactor.
Also preferably the apparatus comprises means for 30 transferring sensible heat from the gas discharged from the second gasification furnace to the water or steam prior to its being injected.
The apparatus may comprise heat exchanger means for cooling the gas discharged from the second furnace and for 35 transferriny the heat withdrawn from the gas to one or more of the gasification media introduced into either or both of . . .

131 ~9~3 the furnaces~ preferably at least the second furnace.
In the following the invention will be further described and explained with reference to the accompanying drawings.
There is shown in:
Fig. 1, an incinerator or gasification apparatus including a gas duct passing through the centre of the combustion chamber and a feed means for fresh air provided at the start of the gas duct, Fig. 2, the combustion chamber according to Fig. 1 in a sectional line A - B taken normal to the plane of the drawing of Fig. I, Fig. 3, the combustion chamber including a gas duct passing through the centre of the combustion chamber and a 15 feed means for fresh air provided near the outlet of the gas Fig. 4, the combustion chamber, inc1uding a gas duct starting from the centre of the combustion chamber.
F;g. 5 a diagrammatic vertical sect~on of a multiple stage gasification apparatus according to the invention 20 comprising two beds one above the other supported by fire grate members (sluice members) as described in relation to Figs. 1 to 4;
Fig. 6 a diagrammatic vertical section showing the arrangement side by side of several fire grate members 25 (sluice members) as described in relation to Figs. 1 to 4 to support an embers bed in a gasification or incineration apparatus according to the invention.
Fig. 7 a shaft furnace apparatus acccording to the invention in vertical section adapted for the disposal and 30 gasification of liquid wastes;
Fig. 8 a diagrammatic view, partly in section and not strictly to scale of an apparatus in accordance with the invention for gasifying solid carbonaceous matter followed by cracking of the gas and vapour in a separate embers bed;
Fig. 9 a diagrammatic vertical section of a gasifier apparatus according to the invention, applicable to any of .

~ 131 1923 the embodiments in -the aforegoing, where steam injection is desired;
Fig. 10 a fire grate device of an apparatus according to the invention in vertical section, adapted for embodiments where steam injection is desired.
In the incinerator illustrated in Figs. 1 to 4, the combustion chamber 1 follows a pyrolysis chamber 2 in series; Both chambers are separated from one another by the gate member 3, also referred to herein as a sluice member or 10 fire grate member.
In the case of the combustion chamber illustrated in Figs. 1 and 2, the gas duct 4 passes through the centre of the combustion chamber 1. At the beginning of the gas duct 4 a gas burner 5 is provided servin~ for ignition to start 15 the combustion process in the combustion chamber. The fresh air feedlines 6 is connected to the gas duct 4.
For operating the incinerator, combustible material is charged into the pyrolysis chamber 2 through the upper sluice gate 7. For starting the pyrolysis gas burners 8 are 20 employed. The combustible flue gases formed in the pyrolysis chamber are withdrawn downwardly into the combustion chamber 1. They enter through apertures 9 into the gas duct 4. The apertures 9 are provided on that side of the gas duct which faces the ash discharge means 10, i.e.
25 on the downward side.
During the operation of the incinerator, fresh air is conducted by way of the sluice gate member 3 via the fresh air feedline 11 in a sub-stochiornetrical ratio, both upwardly into the pyrolysis chamber 2 as well as into the 30 combustion chamber 1. As a result, an embers bed is formed above the sluice rnember 3 at a temperature of up to about 800C in which the pyrolysls gases are cracked down substantially or at least partly into short-chain hydrocarbon molecules. The heat generated in the embers bed 35 by partial combustion of the material, results in the pyrolysis of the material prevailing above the embers bed.

The fresh air introduced into the combustion chamber 1 by way o~ the sluice 3, results in a partial combustion of the combustible gases at a temperature not exceeding 800C
in that portion of the combustion chamber 1 which is outside 5 the gas duct 4, resulting in further cracking of tars and tar oils.
Fresh air in at least stochiometrical ratio to the gases is fed into the gas duct 4 by way of the fresh air feedline 6. This results in a complete combustion of the 10 flue gases introduced into the gas duct 4 so that a temperature of about 1100C is attained.
In the embodiment of the combustion chamber illustrated in Fig. 3, the fresh air feedline 6 projects by way of an additional duct member 6a beyond the centre of the 15 combustion chamber into the gas duct 4. The feed position for the fresh air is accordingly close to the outlet of the combustion chamber such that the region of complete combustion of the gases is also positioned close to the outlet of the combustion chamber and the resulting hot flame 20 projects beyond the region of the combustion chamber.
In the embodiment of the combustion chamber 1 111ustrated in Fig. 4 the gas duct 4 starts from the centre of the combustion chamber 1. The gas duct in this case takes the form of a pipe of which the end provided in the 25 combustion chamber is open towards the combustion chamber.
The introduction of fresh air proceeds by suction by way of the duct member 6a projecting into the pipe 4 and which after the swinging down of the gas burner S is open towards the outside.
Departing from the embodiments of the combustion chamber according to the invention illustrated in the drawing,-it may be advantageous, depending on the dimensions of the combustion chamber and for optimising the combustion procedure, to provide more than one gas duct 4 in the 35 combustion chamber, e.g. side by side.
The use of a single duct 4 passing all or part-way ,....

,,"~":

~: ~ . .. .. .. . . . .

;.

131 1~23 through the combustion chamber 2, as described above, is particularly useful in furnaces in which the combustion chamber, or indeed the entire structure, is basically cylindrical. Particularly in the case of furnaces of 5 rectangular horizontal cross-section it may be convenient to provide a co~bustion chamber according to the invention with two or more gas ducts for leading combustible gases out of the combustion chamber in a path where they can be consumed at a temperature higher than that which is found in the 10 remainder of the combustion chamber. The plural gas ducts are preferably of the same construction, but they may be of any of the kinds illustrated in the other figures, for exarnple. Furthermore, although horizontal disposition of the gas ducts, in which the high temperature complete 15 combustion takes place, is particularly convenient in an incinerator furnace in which there is a pyrolysis chamber above the combustion chamber constituted according to the invention, it is evident that there may be applications of the combustion chamber according to the invention in which 20 the gas duct leading out of the combustion chamber is disposed obliquely or vertically.
An important aspect of the invention, and which has utility regardless of whether or not the pyrolysis gases are combusted in a combustion chamber as described above, or are 25 subjected to other uses (e.g. for suitable combustion engines), or regardless of whether or not the pyrolysis apparatus is operated with air or oxygen or oxygen-enriched air and with or without injection of steam - regardless of the pressure at which the apparatus is operated - resides in 30 the following features of the sluice member 3.
According to this aspect of the invention there is provided a gasification apparatus for converting solid combustible materials into combustible gases ~which term may include generator gas, water gas and various grades of 35 synthesis gas, comprising a sluice member 3, sub-dividing the interior of the gasification apparatus to an upper, '' 25 ' ' first pyrolysis stage or chamber 2 and a lower, second partial combustion stage or chamber 1. According to this further aspect of the invention, the sluice member 3 has downwardly inclined flanking faces, the lower edges of which 5 each define a gap for the passage of the glowingembers from the first pyrolysis chamber 2 into the second partial combustion chamber 1. The sluice member 3 is mounted pivotally as shown in the drawing, in end bearings permitting back- and forth-tilting (e.g. intermittently) of 10 the sluice member 3 to increase or decrease the size of the gaps on either side, thereby promoting the passage of the material.
As a preferred feature the sluice member 3 comprises one or more upwardly projecting members (which, as shown in 15 the drawings) serve to supply sub-stochiometrical amounts of air or oxygen to the upper first pyrolysis stage. However, in accordance with the present further feature of the present aspect of the invention, these upwardly projecting member(s) provide an important function as well in that they 20 participate in the pivoting or tilting movements of the sluice member and thereby also act mechanically on the embers in a manner which promotes the desirable physical structure of that bed.
Important further aspects of the invention relate to 25 certain features of the sluice device 3. These aspects have utility not only if the apparatus according to the invention is employed as an incinerator and/or for the production of a heating gas~to be burned for heat generation in the devices 4 illustrated in the drawings. These aspects may also find 30 utility in the generation of producer goes for powering internal combustion engines ~in particular diesel or spark ignition) or for producing synthesis gas from solid fuels such as wood, peat, brown coal or hlack coal. In the case af synthesis gas production, it is normally the practice to 35 employ oxygen or oxygen-enriched air and steam as a ~ gasifying medium, rather than air alone. Moreover, it is ,~

r ~ ~ -1 3 1 ~ 9 2~

- generally advantageous in that case to operate the generator at a pressure exceeding atmospheric pressure to a greater or lesser extent. These are matters readily understood by persons skilled in the art.
As will be apparent from the drawings already described and in particular Fig. 2, read with Fig. 1. the invention according to the further aspects now to be described provides an apparatus for converting a bed (the top level of which is shown in chamber 2) composed of solid combustible carbonaceous materials (e.g. wood or other biomass, or coal) by reaction with substochiometrical amounts of oxygen in a gasifying medium, introduced to the various feed means described above into combustible gases, namely carbon monoxide and hydrogen and greater or lesser amounts of volatile hydrocarbons and other gas~s.
The bed comprises a plurality of zones, namely (from the top downwards): an upper drying zone reaching e.g. down to about the level halfway between the top of the bed and the upwardly projecting member of the sluice device 3; a degassing zone in which volatile constituents are driven off, reaching down to about halfway between the top of the upwardly projecting member of the sluice device 3 and the bottom; and a gasification zone (e.g. at 800C) in which the residual char of the degassing zone ~in form of glowing embers) is converted into C0, H2 and C02 reaching down to the level of the gap between the sluice device 3 and the wall of the reactor.
The combustible gases are withdrawn generally downwardly through the bed into and through the chamber 1 for further combustion in means 4 or for withdrawal to other uses through the pipe 4.
; The~apparatus comprises at least one sluice device 3 defining the lower limit of a zone of the bed. As will be seen, the sluice device is similar to that shown in Fig. 2 of D~E-PS 27 34 973, being mounted pivotally about a s~ubstantially horizontal axis, being the axis of the pipe -~ ~ 27 ,, ,, ~f ~: ,:

l1. The sluice device 3 comprises on both sides of the axis upwardly directed, downwardly sloping, flanking surfaces for carrying the bed, ter~inating in lower edges, each defining one side of a gap for the controlled passage of bed 5 material. The other side of the gap is formed by the walls of the generator vessel.
The passage of the bed material through the gap is assisted by alternatingly increasing and decreasing the size of the gap. This is done by the up and down tilting lO movements of the sluice device (3). So far the operation of the sluice device is identical to that described in DE-PS 27 34 973.
According to the invention the sluice device carries substantially vertically upwardly projecting means, which 15 may be in the form of individual upwardly projecting pipes or may take the form of a continuous upwardly extending web or fin. In either case these means will participate in the back and forth tilting movement of the sluice member, thereby exercising a desirable mechanical disturbing action 20 on the bed. These means projecting upwardly from the apex formed by the sloping flanking surface include discharge apertures capped by roof-shaped formations for introducing gasifying medium, e.g. air, 1nto the bed.
In addition the sluice member includes discharge 25 apertures for the separately controlled introduction of gasifying medium, respectively combustion medium, directed downward from the underside of the sluice device.
The apparatus may comprise two or more of the sluice devices side by side, separated by the gaps, to form a grid.
30 In this manner it is possible to increase the size and capacity of the apparatus, whilst maintaining a bed of good quality. ~It is also possible to install two or more of the sluice members one above the other to define different zones of the bed. These possibilities will be described with 35 reference to Figs. 5 and 6, wherein in general the same reference numbers are employed as in Figs. 1 to 4.

~- ~ 28 ~

1 31 1 92~
It is also possible to apply the apparatus to the gasification of liquid wastes as will be explained more fully with reference to Fig. 7. Figs. 7 to 8 moreover illustrate the upgrading of gases produced in any of the 5 embodiments of the invention by cracking in a separate and distinct embers bed.
Finally Figs. 9 and 10 demonstrate how steam injection can be applied to the embodiments according to the remaining figures.
Referring first to Fig. 5, two fire grate members 3' and 3" are provided one above the other, each supporting a bed in upper portion 2' and lower portion 2" of the - pyrolysis chamber. The intermittent tilting movement of fire grate member 3' controls the rate at which the embers bed in portion 2' passes the gaps between member 3 and the walls of the furnace to form a further bed in lower portion 2". The intermittent tilting movement of the lower fire grate member 3" in likewise manner to member 3' controls the reconstitution of the bed due to the horizontal to and fro agitation exercised by the upwardly projecting part 3a and the up and down displacing action exercised by ~he inclined flanks. In addition the tilting movement, by increasing and decreasing the sizes of the gaps at the opposite lower edges of the inclined flanks controls the rate of downward travel of the bed by contro11ing the rate at which the gasification residue, mostly ash, is discharged into the ash pit of the apparatus. The embodiment according to Fig. 5 is particularly intended for the gasification of solid fuels such as coal which are relatively inert.
2eferring now to Fig. 6, the fire grate member 3 which is considered novel per se is also particularly suitable for large gaslfiers or incinerators in which a plurality of such members 3 are placed side by side, spaced apart by gaps controlled by the above-described tilting movement to form a composite fire grate. Above the fire grate and horizontally staggered in relation to the fire grate members 3 may be :

' ::

----" 1 31 1 923 .
additional feed means 8' for air or gasifying medium. These may be similarly pivotally mounted about their respective axis, thus serving as agitating means which also assist in maintaining a favourable bed condition.
In contrast to what is shown in Figs. 1 to 4 the upward projecting parts 3a of the fire grate members in Figs. 5 and ~ take the form of continuous double-walled webs extending over the full length of the fire grate member.
This can have a configuration as illustrated or a lO different configuration achieving the same purpose. For example the sides of the upwardly projecting part may have sides inclined at a wider angle to one ano~her than that shown, provided such angle is an acute angle, i.e. of less than 9O~C, preferably not more than 45C. Also the angle l5 between the flanking sides of the fire grate member may be more acute than that shown in Figs. 5 and 6 and may be from about 45~C upward, as long as it is not less than the overall angle of taper of the sides of the upwardly projecting part. Generally the upwardly projecting part 20 extends a distance from the tilting axis 3b as large or larger than the distance by which the flanking sides extend sideways from the tilting axis 3b.
Referring now to Fig. 7, a shaft furnace is illustrated the shaft space 2a of which is adapted to be closed in a gas-tight manner in its upper region at 7a. A shaft wall 2b in the downward direction comprises an aperture for accommodating a grate 3"' which in the working example is provided in the shaft in a manner rotatable about its shaft axis 16. The grate 3"' is so inserted in the shaft that a gap 15 serving as a passage is left between the edge of the grate 3"' and the shaft wall 2b. Ash is withdrawn through the gap under the action of gravity from an embers bed 2c formed above the grate and supported by the grate. The grate 3"' is of conical configuration. The ash which is to be withdrawn slides over the conical surface towards the gap 15 serving as a passage.

:: .
,: 30 :~ , :

' ~. ~ . ,.,~, .

The withdrawal of the ash is controlled by the rotation of the grate. For that purpose the grate 3"' is fixed to a drive shaft 17 which is adapted to be turned stepwise by a motor 28 by way of a transmission 29. As the frequency of steps is increased and as the amplitude of thesteps and the rate of rotation of the grate is increased, the rate of ash withdrawal increases.
Instead of a rotating grate it is also possible and in fact preferred to employ a grate as described with reference to Figs. 1 to 6 which is pivotal to tilt back and forth about an axis normal to the axis 16 of the shaft. In the case of a tilting grate a gap for the passage of material is formed between the edge of the grate and the wall of the shaft, the width of the gap being varied by the movement of the grate. As the selected angle by whi-ch the grate is deflected by the pivotal tilting movement is increased, the variation of the width of the gap between a minimum and a maximum value is also increased. Blockage of the gap for passing material due to jamming of ash particles is counteracted thereby. A tilting grate is possible even if the shaft furnace is cylindrical as shown and also offers advantages when the shaft furnace has to be cleaned. For cleaning the gap serving as a passage is widened by tilting the grate to such an extent that all solid pieces present in the shaft furnace can be discharged in a downward direction.
If the tilting grate is made of a prismatic configuration, the ash to be discharged from the embers bed will also with this grate slide towards the gap serving as a passage over an inclined surface. Above the embers bed 6 a feed duct lO
- 30 for the liquid wastes enters into the shaft 2a of the shaft - furnace. The duct 30 is connected to a metering device 31 connected to a storage vessel for the liquid waste. The storage vessel is not illustrated in the drawing. The quid waste comprises organic components. The working example relates to paint wastes comprising organic components such as solvents, thixotropic agents or dyes as ~ 31 131 lq23 well as inorganic additives such as pigment or fillers.
However, it is also possibie to process lacquer sludges.
The metering device 31 comprises a liquid pump which can be regulated or an adjustable valve by means of which 5 the feed rate of the liquid wastes to the shaft furnace can be regulated. Nozzles for spraying the liquid waste may be provided at the outlet of the feed means 30 in the shaft space above the embers bed 2c. In the working example the liquid waste is simply fed dropwise onto the embers bed.
In order to feed oxygen to the embers bed 2c, the drive shaft 17 of the grate 3"' takes the form of a hollow tube, the outer end 13 of which, downwardly projecting from the bottom 12 of the shaft being connected to a gas duct 14 supplying oxygen or air. The oxygen flows in the hollow 15 tube to the apex 35 of the cone of the grate 3"' and is introduced into the embers bed 2c by way of outlet apertures 37 symmetrically provided around the cone axis 16. In the working example the cone axis 16 coincides with the shaft axis 16. The conical grate may, however, also be fitted in 20 the shaft furnace to move in a tumbling manner.such that the width of the slot for the passage between the edge of the grate and the shaft wall undergoes local variation when the grate ls turned.
Departing from the working example illustrated in the ~5 drawing, the grate 3"' may also be provided with outlet apertures for oxygen or air at various levels of the conical grate. For example it is also possible for oxygen or air to be fed in addition into the embers bed only slightly above the gap 15 serving as the passage. This is desirable in 30 particular if the fuel gas to be withdrawn from the shaft furnace is to be converted immediately and be burned for heat generation.
The amount of oxygen introduced at the apex 35 of the cone is preferably so dimensioned that the temperature of 35 the embers bed required for the cracking of the gases is maintained within the shaft furnace by the partial , :

.

combustion of the gases formed in the embers bed. In the working example the embers bed is composed of coke which can be charged through a closable aperture 7a at the top of the shaft. The embers bed has a temperature between 800 and 5 1000C. The temperature of the embers bed must be so adjusted that the organic products formed by the gasification of the paint wastes are cracked when the gases pass through the high temperature zone. In the working example the temperature is set to 800 to 900C because the 10 shaft furnace is followed in series by a cracking and cl'eaning stage 23., The gas mixture generated in the embers bed 2c is sucked off by way of a withdrawal duct 18 in the lower region of the shaft furnace. Accordingly the gas flows l5 through the shaft furnace in cocurrent with,the liquid wastes being fed into the shaft. A blower 20 installed in the discharge duct 19 provides in the working example the necessary suction pressure. The gas mixture and the ash particles are separated from one another after the passage 20 through the gap 5. The ash particles initially collect at the shaft bottom 12 and are conveyed by scoops 12a to the withdrawal duct 18 through which they drop into an ashpit 21. From there they can be discharged by way of a sluice 22.' In the working example the shaft furnace described above is followed in series by a second cracking and cleaning stage 23 for cracking the residual high molecular weight hydrocarbons of the gas mixture generated. The cracking and cleaning stage 23 similarly comprises an embers bed 24, the embers bed being supported by a grate 24a, the temperature of the embers bed being set to a range between 900 and 1000C. The discharge duct 18 connected to the shaft furnace enters below the embers bed 24 into the cracking and cleaning stage. The gas mixture introduced is subse~uently discharged at the head of this stage by way of the outlet 19. Not only are the high molecular weight organic gas components still contained in the gas mixture subjected to cracking in the embers bed 24, but a cleaning effect is also attained. Ash particles entrained by the gas mixture are retained. From the cracking and cleaning stage 5 23 a gas mixture emerges which essentially comprises H2. CO, CH4 and which can immediately be utilised as a fuel gas optionally after intermediate storage, e.g. in pressurised storage means.
Above the embers bed 24 a closable charging aperture 25 10 is provided for coke which in the working example serves as the fuel for the embers bed 24. However, charcoal may also be used as a degassed material rich in carbon. Oxygen is not fed to the cracking and cleaning stage 23 in the working example. It is assumed that the oxygen fed to the fuel gas 15 in the shaft furnace is also sufficient for a partial combustion of the fuel gas in the cracking and cleaning stage 23 in order to maintain in the cracking and cleaning stage the temperature of the embers bed required for cracking the gas components. This reduces the fuel requirements for 20 this stage.
In a shaft furnace of the above described type having a shaft volume of 100 dm3 up to 50 kg lacquer sludge per hour were gasified. The lacquer sludge contained between 40 and 50 mass percent of inorganic additives. The temperature 25 in the embers bed 2c was set to approximately 900C and the temperature in the embers 24 to about 1000C. Coke having an average particle size of from 10 to 30 mm diameter was used for forming the embers beds.
The fuel gas emerging from the outlet 19 had producer ?
30 gas quality. The combustible gas components such as CO, H2, CH4 made up 55 volume percent. It was possible to generate gas in an~amount of 250 normal m3 per hour having a heating value of 5000 kilojoules/Nm3, Other liquid wastes comprising organic components which 35 may be used include for example oily or fatty solutions or slurries. from such waste liquids as well it is possible to - ... . . .. . _ . _ . .

~. .

. ' , -~ 131 1923 generate fuel gas in the same manner. Besides the disposal of such liquids, the process at the same time serves to save fossil fuels.
The invention as exemplified was found to provide a 5 process for the disposal of liquid wastes comprising organic components which is friendly to the environment and which moreover can be operated with useful energy gains. In addition the process was found to be suitable for being practised in a simple manner.
It will be understood that the invention can be practised to produce mixtures of gases derived in optional ratios within wide limits of gas derived from the liquid wastes and gas derived from the embers beds.
Referring now to Fig. 8, there is shown a first l5 gasification furnace or generator 51 connected in series by way of a connecting duct 53 to a much smaller second gasification or generator furnace 52 of similar design to the first furnace 51. The furnaces 51 and 52 comprise fuel hoppers 53 and 54 respectively each feeding through a sluice 20 lock device 55 and 56 respectively, having top and bottom slider gates 57, 58 and 59, 60 respectively or equivalent means, whlch are known per se and require no detailed description.
Each gaslfication furnace furthermore comprises a grate 25 device 61 and 62 respectively ~corresponding to grate 3 in Figs. 1 to 4) in the form of a prismatic member comprising downwardly ~nclined flanks 63 and 64 respective1y, the lower edges of which stop just short of the walls of the respective furnace 51, 52 to form gaps 65 and 66 30 respectively for the controlled passage of solid matter.
Each grate member 61 and 62 is adapted to be pivoted back and forth about an axis 67 and 68 respectively to cause a mechanical disturbance of the fuel bed supported by each of the grates and to cause alternating narrowing and widening 35 of the gaps 65 and 66, whereby the discharge of solid matter, more particularly ash through the gaps i s , , ~ ~ 35 ,,~ ~ -, , controlled.
Each grate member 61, 62 furthermore comprises coaxial with its pivoting axis 67 or 68 a feed duct 69 or 70 respectively for the introduction of gasification medium.
5 These feed ducts feed at least in part into upwardly directed hollow webs 71 and 72 respectively, terminating in outlets 73 and 74 respectively, protected in an upward direction by roof-like baffles 75 and 76 respectively.
In the case of the grate member 61 of the first lO gasification furnace 51, the feed duct 69 is subdivided into two parts, only one of which feeds into the upwardly directed web 71, whilst the other one is adapted to discharge the same or a different gasification medium through gaps 77 in the inclined flanks 63 of the grate 15 device 61.
In the drawing only a single grate device 61, 62 is shown in each of the gasification furnaces. However, two or more such devices may be provided side by side separated by gaps 65 to provide a grate of double or multiple cross 20 sect~onal area. The grates each support a solid fuel bed, the tops of which are denoted as 78 and 79 respectively.
Near the tops of the beds 78 and 79 the furnaces furthermore each provide additional feed means 80 and 81 respectively for an oxygen-containing gasification medium, e.g. air blown 25 into the furnaces by blowers 82 and 83 respectively.
Each gasification furnace 51, 52 furtherrnore comprises an ash pit 84 and 85 respectively and an ash discharge sluice 86 and 87 respectively.
The connecting duct 53 has its inlet aperture 88 30 immediately below and sheltered by the grate member 61 and enters the second furnace 52 at a locality near the top 79 of the fuel bed.
The inlet aperture 89 of the discharge duct 40 of the second furnace 52 also is positioned immediately below the 35 grate member 62. It passes into a heat exchanger device 41 for cooling the gas which may for example comprise separate ~ .

1 31 1 9~3 sections 42 and 43. Section 42 receives at 44 water or steam which in section 42 picks up serlsible heat from the hot gases. Hot steam is discharged through duct 45 to be passed for example to the first gasification furnace, e.g.
5 to the duct means 69 and/or to the inlet means 80 for gasification medium.
The second heat exchanger section 43 is fed at 46 with oxygen-containing gasification medium, e.g. air or oxygen-enriched air which is heated in section 43 and then passed 10 to duct 70. The gas leaving the heat exchanger at 47, e.g.
withdrawn by a sustion fan (not shown) may if necessary, pass through further cleaning means, e.g. a gas scrubber and/or a filter, before being fed at 48 to an internal combustion engine 49 which drives a generator 90.
It will be appreciated of course that instead of a single gasification furnace 51 being connected in series with the gasification furnace 52, there could be two or more gas generators 51 feeding into a single furnace 52.
The fire grate members 61 and 62 are mounted pivotally 20 about their axes 67 and 68 respectively and are connected to a mechanism (not shown) adapted to impart a to and fro pivoting movement about an angle and with a speed and fre4uency which can be adjusted at will. The angle determines the degree of variation of the s1zes of the gaps 25 65 and 66, and the factors just described, determine the rate at which ash is withdrawn from the bottom of the embers bed into the ash pits 84 and 85 respectively. For cleaning of the apparatus the grate member may be tilted more substantially so that any solid matter supported by the 30 grate will fall through.
The pivoting movement also has a further desired effect in that the upright web members 71 and 72 respectively rock to and fro, thereby to disturb the bed supported by the grate. This assists in the avoidance of channelling and 35 generally modifies the structure of the bed in a desired manner.

The apparatus according to Fig. 8 may be operated as follows:
Gas generator 51 is charged with a high volatile South African duff coal having a high ash content of between 20 and 25%, about 25% by mass volatile content based on dry matter and an ash softening temperature in the region of 1000C.
The particle size ranges from about 1 mm upwards to nut size, although larger pieces may be present.
Generator 52 is supplied with anthracite having a volatile content of between 5 and 6%, an ash content of about 6% and an ash softening temperature in the region of 1500 C.
During the starting up phase the fuel beds in both generators are ignited with a propane gas burner (not shown) and by introducing air through the blowers 82 and 83 respectively. In the case of gas generator 52 the air introduction at 81 using blower 83 is employed only during the starting up phase, until a strongly incandescent high temperature embers bed has been formed. In the case of generator 51, air introduction at 80 by means of the blower 82 is continued throughout the process and regulated to maintain the desired temperature conditions.
In generator 51 a mixture of air and steam is introduced via duct 69 through outlet apertures 73 and 77.
The overall ratio of air to steam in generator 51 is adjusted to that ratio which corresponds to steam saturation at 50 C. Blowing of air and steam is also so adjusted that the temperature in the region of highest incandescence just above gaps 65 is about 900 C. The first high temperature gasification zone where the temperature ranges from about 700 to 900 C which is below the ash softening temperature of the coal extends from about the level of baffle 75 to the gaps 65. The degassing zone in the fuel bed where the temperature ranges from about 400 to 700 C extends from approximately the level of baffle 75 to the level of air inlet nozzles 80. The steam which is introduced through pipe , .. . .
: , . , .
.
- .

. .
- . , 131 lq23 45 has been preheated by heat exchange to utilise some of the sensible heat of the gases produced, and this is a further factor which can be used to control the temperature in the gasification zone. The steam lowers the temperature in the first high temperature zone, due to the reaction of coal with water being endothermal. On the other hand in the presence of water the temperature required for total gasification of coal is also lower than in the absence of water. At the relatively low temperatures prevailing in the gasification zone, the carbon content of the embers bed is converted into a mixture of carbon dioxide, hydrogen and carbon monoxide, some methane being also formed. More methane results from the degassing reaction and the partial cracking of volatiles liberated in the degassing zone and drawn through the embers bed.
In the generator 52 a highly incandescent embers bed having a temperature of 1000 to 1400 C, preferably 1000 -1200 C that is below the ash softening temperature of the anthracite, is maintained in the region between gaps 66 and the feed apertures 74 for the gasification medium. The high temperature is maintained by the blowing of air preheated in heat exchanger section 43 through duct 70 and feed outlets 74. Optionally the air may be enriched with oxygen, or pure oxygen may be employed or oxygen and steam or oxygen and C02. ~ptionally some air or oxygen may also be introduced into the gas in the connecting duct 53 to raise the temperature of the gas entering the second gasifier 52 by partial combustion. The temperature maintained in the embers bed of gas generator 52 is maintained at such a high level that the gas withdrawn through outlet 89, 40 is substantially free of tars and tar oils. The fuel consumption in generator 52, based on fuel value of the combustible matter is maintained at between 10 and 15% the consumption in generator 51.
In a different embodiment generator 51 is fuelled with domestic garbage pellets produced according to the process of the Swiss firm Orfa. In that case no steam injection is resorted to, generator 51 being operated with air only, introduced at 80 and 83.
The invention as set out above can also be applied to 5 enable the first high temperature zone to be maintained in a temperature range in which exposure of various parts of the first gasifier furnace to excessively high temperatures is avoided or minimised, as a result the life expectancy of heat exposed components may be improved or such components 10 can be manufactured of less expensive materials which would not survive at much higher temperatures.
The invention can also be conducted as a pressure ?
gasification process, and even using only oxygen and steam and optionally CO2 as gasification medium. The oxygen tends 15 to raise the temperature of the high temperature zones, whilst the steam tends to depress this temperature. Because of the splitting of the gasification apparatus into two furnaces as taught by the present invention, it is possible to operate the first furnace under relatively depressed 20 temperature conditions which may be preferred for a variety of reasons, be it to ensure that the ash softening temperature or the temperature of volatilisation of certain components, e.g. heavy metals, in the first high temperature zone is not exceeded, or be it to restrict thermal loading 25 of the equipment of the first furnace, or be it merely to promote the complete gasification of the material in the first high temperature zone by the maintenance of a relatively high water content, and regardless of whether or not the resultant gas already has the desired composition 30 and purity. The latter two factors may then be modified to the desired extent in the second high temperature zone.
The claims that follow are to be considered an integral part of the present disclosure.

.

Claims (108)

1. Process for the gasification of solid or solid and liquid organic, i.e. carbonaceous matter by partial combustion with a gasifying medium comprising oxygen, or oxygen and steam or oxygen and carbon dioxide, wherein the organic matter is first subjected to partial combustion and pyrolysis at a temperature within the range of from about 400°C upwards, but below the ash fusion or softening temperature of the organic matter in a first gasification treatment, whilst being supported above a fire grate or equivalent partition means in the presence of substochiometrical amounts of oxygen introduced with the gasifying medium, whereafter gases generated in the first gasification treatment are subjected to thermal cracking in at least one further heat treatment again in the presence of oxygen, the further heat treatment being carried out either avoiding direct contact with ash or ash-containing residue of the organic matter formed in the first gasification treatment, also in the presence of oxygen, or, provided the ash of the organic matter has a melting or softening temperature above the temperature of the further heat treatment, in an embers bed, including said ash, confined in a constricted passage supported by the same or yet a further fire grate defining at least one variable gap constituting the lower limit of the passage and controlling the rate of gradual downwards travel of the embers bed.

2. Process according to claim 1, wherein gases formed in the first gasification treatment are recycled to where the first gasification treatment takes place, thereby being subjected to thermal cracking by further heat treatment in the presence of oxygen introduced with the gasifying medium.

3. Process according to claim 1, wherein the partial combustion and pyrolysis takes place under downdraft conditions in a bed subjected to mechanical internal reconstitution by back and forth agitation in predominantly horizontal direction.

4. Process according to claim 3, wherein simultaneously with the back and forth agitation the size of a variable gap constituting the lower limit of a passage through which the bed travels gradually downward is increased and decreased, thereby regulating the rate at which the bed travels.

5. Process according to claim 3, wherein the mechanical agitation is brought about by back and forth tilting about a horizontal axis of an agitating member.

6. Process according to claim 5, wherein simultaneously with the back and forth horizontal agitation the bed is subjected to an up and down displacement action.

7. Process according to claim 5, wherein the agitating member is also used for feeding gasifying medium into the bed.

8. Process according to claim 6, wherein the agitating member projects upwardly from a fire grate member defining the lower limit of the bed, mounted pivotally about a substantially horizontal axis and comprising on both sides of the axis upwardly directed, downwardly sloping flanking surfaces which carry the bed, the lower edges of the flanking surfaces each defining one side of a gap controlling the passage of bed material, the width of the gap being varied when the fire grate member is tilted back and forth, thereby subjecting the bed to the horizontal agitation and the up and down displacement action.

9. Process according to claim 1, wherein the further heat treatment takes place under downdraft conditions in a bed subjected to mechanical internal reconstitution by back and forth agitation in predominantly horizontal direction.

10. Process according to claim 9, wherein simultaneously with the back and forth agitation the size of a variable gap constituting the lower limit of a passage through which the bed travels gradually downward is increased and decreased, thereby regulating the rate at which the bed travels.

11. Process according to claim 9 wherein the mechanical agitation is brought about by back and forth tilting about a horizontal axis of an agitating member.

12. Process according to claim 11, wherein simultaneously with the back and forth horizontal agitation the bed is subjected to an up and down displacement action.

13. Process according to claim 11, wherein the agitating member is also used for feeding gasifying medium into the bed.

14. Process according to claim 12, wherein the agitating member projects upwardly from a fire grate member defining the lower limit of the bed, mounted pivotally about a substantially horizontal axis and comprising on both sides of the axis upwardly directed, downwardly sloping flanking surfaces which carry the bed, the lower edges of the flanking surfaces each defining one side of a gap controlling the passage of bed material, the width of the gap being varied when the fire grate member is tilted back and forth, thereby subjecting the bed to the horizontal agitation and the up and down displacement action.

15. Process according to claim 1, wherein the partial combustion and pyrolysis takes place under downdraft conditions in a first bed supported by a fire grate member defining the lower limit of the bed, mounted pivotally about a substantially horizontal axis and comprising on both sides of the axis upwardly directed, downwardly sloping flanking surfaces which carry the bed, the lower edges of the flanking surfaces each defining one side of a gap controlling the passage of bed material, the width of the gap being varied when the fire grate member is tilted back and forth, and wherein the bed material discharged from the first bed drops onto and forms a second bed underneath the first bed, supported in substantially the same or similar manner as the first bed, the gas generated in the first bed in the first gasification treatment leaving the first bed through the gaps at the bottom of the first bed being passed under downdraft conditions through the second bed for further heat treatment.

16. Process according to claim 15, wherein at least one of the beds is subjected to mechanical internal reconstitution by the back and forth agitation action of an agitating member projecting upwardly from the fire grate member supporting the bed.

17. Process according to claim 15, wherein at least one of the beds is supplied with gasifying medium or steam or both through a feed member projecting upwardly from the apex of the fire grate member supporting the bed.

18. Process according to claim 1, wherein a further heat treatment of the gas takes place substantially out of direct contact with the ash or ash-containing residue formed in the first gasification treatment, which comprises passing the gases emerging from the first gasification treatment into a combustion chamber and there adding to the gas further oxygen or oxygen-containing gas in an amount sufficient to raise the temperature of the gas by combustion reactions above the temperature of the first gasification to bring about thermal cracking of crackable compounds of the gas.

19. Process according to claim 18, wherein air or oxygen is first added in substochiometrical proportions whereafter the hot gases are led into a duct where further air or oxygen is added to complete the combustion of the gas.

20. Process according to claim 19, wherein the sensible heat of the combustion gases is used for heating purposes.

21. Process as claimed in claim 1 for the combustion of combustible material in which the combustible material is pyrolysed and combusted with air starvation and in which the resulting combustible gases are fed into a combustion chamber, there to be combusted after the prior admixture of air, in which the gases are fed inside the combustion chamber into a gas duct provided in the combustion chamber which is open towards the interior of the combustion chamber and is conducted inside the gas duct separately towards the outlet or outlets of the combustion chamber, fresh air being admixed into the flue gases flowing through the gas duct.

22. Process according to claim 21, in which the gases, starting from the centre of the combustion chamber or passing through the centre of the combustion chamber, are conducted separately.

23. Process according to claim 21, in which the gases fed into the combustion chamber are supplied with fresh air in a sub-stochiometric ratio and additional fresh air is fed in an at least stochiometrical ratio to the separately conducted gases.

24. Process according to claim 1, wherein the further heat treatment takes place out of direct contact with the ash or ash-containing residue of the organic matter and which comprises maintaining a second high temperature zone, separated and remote from the first gasification zone and maintained at a temperature sufficiently high for substantially complete cracking of tars and tar oils, wherein the second high temperature zone comprises an embers bed formed by a solid carbonaceous fuel producing substantially no fused or softened ash at that temperature.

25. Process according to claim 24, applied to the high temperature gasification of solid carbonaceous matter by partial combustion.

26. Process according to claim 24, applied to the gasification of liquid wastes comprising organic components, wherein the liquid wastes are applied onto an embers bed to convert the liquid wastes into gaseous products, the gaseous products being withdrawn through the embers bed and in the course thereof being so heated in the embers bed that high molecular mass organic components in the gas are cracked, the withdrawn gas mixture cleared off ash particles, serving as a fuel gas.

27. Process according to claim 26, wherein the embers bed comprises at least one temperature zone having a temperature in a range of from 800 C upwards, through which the gaseous products have to pass.

28. Process according to claim 27, wherein the gaseous products after a first separation therefrom of ash particles are once again subjected to cracking and purification in a second stage at a temperature between 900 and 1500 C.

29. Process according to claim 28, wherein the gaseous products flow through a second embers bed in the second stage.

30. Process according to claim 26, wherein for the formation of the embers bed degassed material of high carbon content is used.

31. Process according to claim 26, wherein the embers bed has added thereto grinding mill balls.

32. Process according to claim 26, wherein the liquid wastes are sprayed over the embers bed.

33. Process according to claim 27, wherein the high temperature zone is from 800 to 1000°C.

34. Process as claimed in claim 1 for the gasification of liquid wastes comprising organic components, wherein the liquid wastes are applied onto an embers bed to convert the liquid wastes into gaseous products, the gaseous products being withdrawn through the embers bed and in the course thereof being so heated in the embers bed that high molecular mass organic components in the gas are cracked, the withdrawn gas mixture cleared of ash particles, serving as a fuel gas.

35. Process according to claim 34, wherein the gaseous products and vapours after a first separation therefrom of ash particles are once again subjected to cracking and purification in a second stage at a temperature which is higher than that of the embers bed where the gases and vapours had been formed.

36. Process as claimed in claim 1 for the high temperature gasification of solid carbonaceous matter by partial combustion with a gasifying medium comprising oxygen in a first high temperature zone to form a combustible gas followed by passing the combustible gas through a second high temperature zone, separated and remote from the first zone and maintained at a temperature sufficiently high for substantially complete cracking of tars and tar oils, wherein the second high temperature zone comprises an embers bed formed by a solid carbonaceous fuel producing substantially no fused or softened ash at that temperature.

37. Process according to claim 36, wherein the solid carbonaceous matter has an ash fusion or softening temperature below the temperature maintained in the second high temperature zone and the temperature of the first high temperature zone is maintained at a level to gasify the carbonaceous matter without fusing or softening the ash.

38. Process according to claim 36, wherein the second high temperature zone is operated under downdraft conditions.

39. Process according to claim 36, wherein the solid fuel in the second high temperature zone is substantially free of tar- or oil-yielding volatiles and the second zone is operated under updraft or downdraft conditions.

40. Process according to claim 36, wherein the first high temperature zone is operated under downdraft conditions, and the first high temperature zone is provided by an embers bed formed by the solid carbonaceous material.

41. A process according to claim 36, wherein the solid carbonaceous matter is brown or black coal.

42. A process according to claim 41, wherein the coal is a high-ash, high-volatile duff coal.

43. A process according to claim 41, wherein the solid carbonaceous matter comprises waste coal or coal having an ash content in excess of 25% by mass based on dry matter.

44. A process according to claim 36, wherein the solid carbonaceous matter comprises domestic garbage.

45. A process according to claim 44, wherein the garbage is introduced in pellet form or other suitable compacted particle form.

46. A process according to claim 36, wherein the solid carbonaceous matter comprises bagasse or wood.

47. A process according to claim 46, wherein the carbonaceous matter has been pelletised and dried.

48. A process according to claim 36, wherein the solid fuel in the second high temperature zone is anthracite or coke having a high ash softening temperature or charcoal.

49. A process according to claim 36, wherein the solid fuel consumed in the second high temperature zone constitutes in terms of fuel value less than half the amount of solid carbonaceous matter gasified in the first high temperature zone.

50. A process according to claim 49, wherein the solid fuel consumption in the second high temperature zone constitutes in terms of fuel value less than 30% the amount of solid carbonaceous matter gasified in the first high temperature zone.

51. A process according to claim 36, wherein the fuel gas produced is cooled and - if necessary after further cleaning - is used to power an internal combustion engine.

52. Process according to claim 36, wherein water is introduced into the gasification medium and/or one of the embers beds.

53. Process according to claim 52, wherein water is introduced at a locality in or preceding the first embers bed.

54. Process according to claim 52, wherein the water is introduced in the form of steam.

55. Process according to claim 54, wherein the steam is generated and/or heated using sensible heat generated by the gasification process.

56. Process according to claim 1 for gasifying in a gasifier furnace solid carbonaceous matter at high temperatures with a gasifying medium comprising oxygen and water (steam) wherein sensible heat generated in the gasification is transferred to the water, and wherein the water is introduced in the form of steam into the gasification chamber from a water jacket means forming part of the confining outlines of the gasifier furnace, in contact with an incandescent region of the furnace interior, the rate of steam introduction being controlled by controlling the water level in the water jacket means.

57. A process as claimed in claim 56, wherein the gases generated are used as synthesis gas directly or after further conversion.

58. A process according to claim 56, wherein the water jacket means form part of the outer upright confining outlines of the incandescent region.

59. A process according to claim 56, wherein the water jacket means form part of fire grate means of the gasifier.

60. A combustion apparatus adapted for carrying out a pro-cess as claimed in claim 1, comprising a pyrolysis chamber including a pyrolysis zone equipped with first air supply means for producing combustible non-gaseous material by incomplete combustion;

a controllable fire grate or equivalent means which forms the bottom of said pyrolysis chamber and which permits passage therethrough of said combustible gases;

a second combustion chamber disposed downstream of said first pyrolysis chamber and fire grate or equivalent means;

second air supply means for introducing air to the combustible gases passing through or emerging from the fire grate or equivalent means for support of partial combustion of combustible matter and where such partial combustion is in contact with ash or ash containing residue to maintain a temperature below the melting or softening temperature of the ash and at least one gas duct passing through the com-bustion chamber or starting from the interior of the com-bustion chamber and comprising one or more apertures leading to the combustion chamber, and one end of which constitutes the outlet of the combustion chamber or is connected there-to, and which is adapted to be connected to a fresh air feed means or for fresh air to be introduced by suction from the atmosphere.

61. An apparatus according to claim 60, in which the gas duct passes through the centre of the combustion chamber or starts from the centre of the combustion chamber.

62. An apparatus according to claim 61, in which the gas duct comprises a pipe having apertures in its wall.

63. An apparatus according to claim 62, in which the gas duct passes through the interior of the combustion chamber the fresh air feed means being adapted to be connected to the end of the gas duct opposite to the outlet of the com-bustion chamber.

64. An apparatus according to claim 61, in which the feed means for the fresh air projects into the gas duct.

65. An incinerator or gasification apparatus comprising the means as claimed in claim 60.

66. Apparatus for converting a bed of solid combustible carbonaceous materials by reaction with substochiometric amounts of oxygen in a gasifying medium into combustible gases, wherein the bed, which progressively moves downwardly comprises a plurality of zones, and the combustible gases are withdrawn generally downwardly through the bed, comprising at least one sluice device defining, the lower limit of a zone of the bed, mounted pivotally about a substantially horizontal axis and comprising on both sides of the axis upwardly directed downwardly sloping, flanking surfaces for carrying the bed, the lower edges of the flanking surfaces each defining one side of a gap for the controlled passage of bed material, the gap being of variable width due to the up and down tilting movement of the sluice device wherein the sluice device carries upwardly projecting means which participate in the tilting movement to act mechanically on the bed.

67. Apparatus according to claim 66, wherein the upwardly projecting means project from the apex formed by the sloping flanking surfaces.

68. Apparatus according to claim 66, wherein the upwardly projecting means include discharge apertures for introducing gasifying medium into the bed.

69. Apparatus according to claim 66, including discharge apertures for gasifying medium, respectively combustion medium, directed downward from the underside of the sluice device.

70. Apparatus for converting a bed of solid combustible carbonaceous materials by reaction with substochiometric amounts of oxygen in a gasifying medium into combustible gases, wherein the bed, which progressively moves downwardly comprises a plurality of zones, and the combustible gases are withdrawn generally downwardly through the bed, comprising at least one sluice device defining the lower limit of a zone of the bed, and terminating in edges each defining one side of a gap for the controlled passage therethrough of bed material, the sluice device being adapted to move to alternatingly increase and decrease the size of the gaps and comprising means projecting upwardly from the sluice device including discharge apertures for introducing gasifying medium into the bed.

71. Apparatus according to claim 70, including discharge apertures for gasifying medium, respectively combustion medium, directed downward from the underside of the sluice device.

72. Apparatus according to claim 70, wherein the sluice device is mounted pivotally about a substantially horizontal axis and comprises on both sides of the axis upwardly directed downwardly sloping, flanking surfaces for carrying the bed, the lower edges of the flanking surfaces each defining one side of a gap for the controlled passage of bed material, the gap being of variable width due to the up and down tilting movement of the sluice device.

73. Apparatus according to claim 72, wherein the upwardly projecting means project from the apex formed by the sloping flanking surfaces.

74. Apparatus according to claim 66 comprising two or more of the sluice devices side by side, separated by the gaps, to form a grid-like fire grate.

75. Apparatus according to claim 66 comprising two or more of the sluice members one above the other to define different zones of the bed.

76. Apparatus according to claim 66 for the production of a motor fuel gas, connected or adapted to be connected to the fuel inlet system of an internal combustion engine.

77. Apparatus according to claim 66 for the production of synthesis gas, installed as part of the synthesis gas system of a synthesis plant.

78. Apparatus according to claim 66 for the production of heating gas and connected to a gas burner.

79. Apparatus according to claim 66 including the means according to claim 60.

80. A gasification apparatus for carrying out the process according to claim 1, comprising a furnace, including a gasification chamber for holding a bed of solid combustible material, the bottom of which chamber is formed by a fire grate or equivalent partition means, feed means for feeding oxygen-containing gas into the gasification chamber and outlet means for discharging gas produced in the chamber, leading into a means for further heat treatment as defined in claim 1, said gasification chamber being adapted to hold solid carbonaceous matter to be gasified including at least a region thereof in a more or less intense incandescent state, comprising a water jacket device or devices bordering the region and forming a confining outline thereof, a level regulating device for controlling the level of water main-tained in the jacket and duct or passage means for releasing steam generated in the jacket means to the interior of the furnace.

81. An apparatus as claimed in claim 80, wherein the level regulating device comprises a float valve.

82. An apparatus according to claim 80, wherein the water jacket device forms upright walls of the furnace.

83. An apparatus according to claim 80, wherein the water jacket device is incorporated in a fire grate device of the furnace.

84. Apparatus according to claim 83, wherein the fire grate device is adapted to support a bed of material to be gasified and wherein the grate device is mounted pivotally about a substantially horizontal axis and comprising on both sides of the axis upwardly directed downwardly sloping, flanking surfaces for carrying the bed, the lower edges of the flanking surfaces each defining one side of a gap for the controlled passage of bed material, the gap being of variable width due to the up and down tilting movement of the fire grate device.

85. Apparatus according to claim 84, wherein the fire grate device carries upwardly projecting means which participate in the tilting movement to act mechanically on the bed.

86. Apparatus according to claim 85, wherein the upwardly projecting means include discharge apertures for introducing gasifying medium into the bed.

87. Apparatus for carrying out a process as claimed in claim 36, comprising two gasification furnaces connected in series and wherein the first gasification furnace comprises a gasification chamber for holding a bed of solid combustible material, the bottom of which chamber is formed by a fire grate or equivalent partition means, feed means for feeding oxygen-containing gas into the gasification chamber and outlet means for discharging gas produced in the chamber, leading into a duct for passing gas generated in the first furnace to the top of the second gasification furnace which is of the downdraft type and likewise com-prises a gasification chamber for holding a bed of solid combustible material, the bottom of which chamber is formed by a fire grate or equivalent partition means, feed means for feeding oxygen-containing gas into the gasification chamber and outlet means for discharging gas produced in the chamber.

88. Apparatus according to claim 87, wherein the first furnace is also of the downdraft type.

89. Apparatus according to claim 87, comprising means for injecting water or steam into at least one of the furnaces.

90. Apparatus according to claim 89, wherein the means for injecting water or steam is in the first furnace.

91. Apparatus according to claim 89, comprising means for transferring sensible heat from the gas discharged from the second gasification furnace to the water or steam.

92. Apparatus according to claim 81, comprising heat exchanger means for cooling the gas discharged from the second furnace and transferring the heat withdrawn from the gas to one or more of the gasification media introduced into either or both of the furnaces.

93. Shaft furnace for carrying out the process according to claim 34, comprising a) a shaft space adapted to be closed in a gas-tight manner in its upper region and limited in a downward direction by a grate serving to support an embers bed to be formed in the shaft space and provided in a rotatable or pivotal fashion in the shaft in such a manner that between the margin of the grate and the wall of the shaft a gap acting as a passage is left for ash particles to be withdrawn under the action of gravity from the embers bed, b) a feed means for a liquid waste material to be applied onto the embers bed and comprising organic components and entering into the shaft space above the embers bed, c) a gas duct for introducing an oxidising agent into the embers bed and maintaining therein a temperature above the cracking temperature of the liquid waste material and below the softening temperature of the ash, and d) a withdrawal means connected below the grate for the gas mixture formed in the embers bed by evaporation and gasification of the liquid waste.

94. Shaft furnace according to claim 93, wherein the embers bed comprises a temperature zone having a temperature in the range between 800 and 1000 °C.

95. Shaft furnace according to claim 93, wherein the withdrawal duct passes to a second cracking and post-cleaning stage adapted for the gas mixture to pass therethrough on its way to the outlet and comprising an embers bed having a temperature between 900 and 1000 °C.

96. Shaft furnace according to claim 95, wherein the embers beds are composed of degassed material having a high carbon content.

97. Shaft furnace according to claim 93, wherein the embers bed in the shaft space has grinding mill balls added thereto.

98. Apparatus for the gasification according to a process as claimed in claim 1 of liquid wastes comprising organic com-ponents, comprising two furnaces, the first one including a gasification chamber the bottom of which chamber is formed by a fire grate or equivalent partition means being adapted to maintain a first charge of glowing solid embers and com-prising means for feeding liquid waste material comprising organic wastes to that charge of embers and feed means for feeding oxygen-containing gas into the gasification chamber to maintain in the embers bed an incandescent state and the second furnace for cracking components of the gas produced in the first furnace, being adapted to maintain a high tem-perature second charge of embers substantially free of vola-tiles, and further comprising means for feeding gas produced in the first furnace from underneath the first charge of embers through the second charge of embers to a withdrawal locality.

99. Apparatus according to claim 98, wherein the first furnace comprises a grate adapted to support a solid fuel and first embers bed under down draft conditions.

100. Apparatus according to claim 98, wherein the second furnace is adapted to support the second charge of embers in the form of a second embers bed and to be operated under updraft conditions.

101. Apparatus for carrying out a process as claimed in claim 1, comprising a gasification chamber for holding a bed of. combustible material and feed means for feeding oxygen-containing gas into the chamber, including a fire grate device for supporting the bed in the apparatus, comprising a bed support member adapted to be tilted back and forth about a substantially horizontal tilting axis and comprising on each side of the axis an upwardly directed downwardly sloping flanking surface for carrying the bed the lower edges of the flanking surfaces each being adapted to define one side of a gap for the controlled passage therethrough of bed material and upwardly projecting means projecting from the apex formed by the sloping flanking surfaces, adapted to participate in the tilting about the tilting axis, for agi-tating the bed.

102. A device according to claim 101, wherein the upwardly projecting means includes a passage for feeding a medium into the bed.

103. Apparatus for carrying out a process as claimed in claim 1, comprising a gasification chamber for holding a bed of combustible material with feed means for feeding oxygen-containing gas into the chamber, including a fire grate for supporting the bed in the apparatus, comprising side by side a plurality of fire grate devices, each comprising a bed support member adapted to be tilted back and forth about a substantially horizontal tilting axis and comprising on each side of the axis an upwardly directed downwardly sloping flanking surface for carrying the bed the lower edges of the flanking surfaces each being adapted to define one side of a gap for the controlled passage therethrough of bed material, one such gap being formed between substantial-ly parallel adjoining edges of any two adjoining fire grate devices.

104. A fire grate according to claim 103, wherein each fire grate device comprises upwardly projecting means projecting from the apex formed by the sloping flanking surfaces, adapted to participate in the tilting about the tilting axis, for agitating the bed.

105. A fire grate device according to claim 104, wherein the upwardly projecting means includes a passage for feeding a medium into the bed.

106. A gasification apparatus for carrying out the process as claimed in claim 1, comprising a chamber for holding beds of combustible material each supplied with oxygen-containing gas or gasification medium and one above the other, suitably spaced apart a plurality of fire grate de-vices, each being adapted to support a bed and comprising a bed support member adapted to be tilted back and forth about a substantially horizontal tilting axis and comprising on each side of the axis an upwardly directed downwardly sloping flanking surface for carrying the bed the lower edges of the flanking surfaces each being adapted to define one side of a gap for the controlled passage therethrough of bed material.

107. A gasification apparatus according to claim 106, wherein at least one of the fire grate devices comprises upwardly projecting means projecting from the apex formed by the sloping flanking surfaces, adapted to participate in the tilting about the tilting axis, for agitating the bed.

108. A gasification apparatus according to claim 107, wherein the upwardly projecting means includes a passage for feeding a medium into the bed.