DE10330859A1 - Operating emission-free gas turbine power plant involves feeding some compressed circulated gas directly to combustion chamber, cooling/humidifying some gas before feeding to combustion chamber - Google Patents

Abstract

The gas turbine power plant operating method involves using residual heat in expanded waste gas for generating steam and/or hot water, feeding a first part of a compressed circulated gas directly to a combustion chamber (2) and cooling a second part (48a) in an intermediate cooler (47) and humidifying it in a humidifying tower (46) before feeding it to the combustion chamber. AN Independent claim is also included for the following: (a) an arrangement for implementing the inventive method.

Description

TECHNICAL TERRITORY

The present invention relates to a method and a device for operating a power plant with a semi-closed CO ₂ process, wherein at least one compressor is arranged, by which recycle gas is compressed, this compressed recycle gas is fed to a gas turbine after passing through a combustion chamber, and wherein a Waste heat boiler is arranged, in which the residual heat contained in the relaxed exhaust gases behind the gas turbine is used to generate steam and / or hot water.

As part of the general efforts to develop power plants that represent the lowest possible environmental impact, there are a large number of different projects whose aim is the development of emission-free gas turbine power plants with a semi-closed CO ₂ / H ₂ O cycle. The use of emission-free gas turbine power plants is currently being considered especially in the oil and gas industry, since the separated carbon dioxide can be used there to a large extent (enhanced oil recovery, EOR) and in some cases sensitive taxes for emitted carbon dioxide have to be paid.

This is mostly used as fuel used natural gas with as much as possible pure oxygen burned. The pure oxygen is used for this an air separation plant. Alternative is it possible with so-called membrane reactors for the oxidation of the fuel to work as they B. in WO 98/55208 and WO 98/55394 are described. Under these circumstances, combustion gases are generated which practically consist only of carbon dioxide and water. Condensed if you get the water out of the working medium, you get largely pure carbon dioxide that liquefies by compression and on different Way can be used or disposed of.

To use the high temperatures As a rule, at the turbine outlet a steam generator is provided, wherein the steam produced is used to do a condensing turbine to drive (bottoming steam turbine).

Alternatively, the generated steam can be pre-expanded in a counter-pressure turbine (topping steam turbine) in order to then be mixed with the working medium of the gas turbine before, in or behind the combustion chamber. The injected steam can then be condensed out together with the water generated by the combustion after flowing through the waste heat boiler. Both concepts are patented EP 0 731 255 A1 described in detail.

The EP 0 939 199 A1 describes a plant in which it is specified how a mixture of water and carbon dioxide is used as the working medium in a semi-closed gas turbine cycle. Among other things, water is injected into the compressor, the combustion chamber and the gas turbine. WO 99/63210 in turn describes a semi-closed combined cycle in which a stoichiometric mixture of water and carbon dioxide is used as the working medium.

The problem with such carbon dioxide cycles is among other things that for conventional use (i.e. normal combustion under supply from carbon dioxide to the atmosphere) designed components for mostly used in a semi-closed carbon dioxide cycle are not optimally designed. Accordingly, it can happen that z. B. when using a bottoming steam turbine or a topping steam turbine expected increased efficiency or additional Performance can not be realized to the extent required and accordingly investments associated with the procurement of such turbines are not justified. The efficiency is also reduced by that the warmth which at the exhaustion of carbon dioxide and water from the recycle stream removed from the system cannot be used to advantage. Ever falls in In the context of such systems, a comparatively large amount of low-temperature heat which is not used optimally.

PRESENTATION THE INVENTION

It is therefore an object of the present invention to provide a method or a device for operating a power plant with a semi-closed CO ₂ process which is simple and does not require high investment costs for its implementation, but its efficiency is still as before is justifiable. At least one compressor is arranged, by means of which recycle gas is compressed, this compressed recycle gas is fed to a gas turbine after passing through a combustion chamber, and a waste heat boiler is arranged downstream of the gas turbine, in which the residual heat contained in the relaxed exhaust gases is used to generate steam and / or hot water is used.

According to the invention, this object solved, that a first part of the compressed recycle gas goes directly to the combustion chamber is fed and a second part of the compressed recycle gas before introduction is cooled in the combustion chamber in an intercooler and then humidified in a humidification tower prior to introduction into the combustion chamber becomes.

The essence of the invention is thus in it by one if possible energetically optimized saturation of the recycle gas with water before it is introduced into the combustion chamber to increase the mass flow through the gas turbine as much as possible and thereby increasing performance. In this way, the efficiency can be changed without major design changes and additional investments (no further steam turbines required) elevated become. The setting of an optimal efficiency is with this Process also increased by that, preferably in a controllable manner, a first part of the compressed Recycle gas is fed directly to the combustion chamber, and a second part the cooling means mentioned respectively supplied for humidification becomes. The necessary components (waste heat boiler, intercooler, humidification tower) are comparatively inexpensive and can especially without much effort when operating with carbon dioxide / water changed Operating conditions to be adjusted.

In connection with the terms used It must be pointed out that under a waste heat boiler there is always a Means to be understood with which the downstream of the gas turbine available waste heat can be used. This can be done for the purpose of extracting Steam or hot water take place, both steam and hot water can either be reused in the gas turbine process itself or but also in a separate use (for example process heat for chemical Investment). Under an intercooler is fundamental to understand a means that can be used to Reduce circulating gas temperature. As a humidification tower to understand a means that is capable of circulating gases moistened by evaporation with water or steam. It can different designs such. B. packed columns are used which consist of a tower in which packing elements are arranged, and in which water flows from top to bottom in the counterflow principle and the circulating gases are led from bottom to top. typically, the circulating gas in the humidification tower to a relative humidity brought in the range of 10 to 20 mass%. The humidification can also take place in two or more stages, e.g. in sequential Befeuchtungstürmen.

According to a first preferred embodiment of the invention, the two partial flows (directly to the combustion chamber or indirectly, d. H. about intercooler and humidification tower) driven relative to each other in a controlled manner. It proves to be advantageous to use the second, via intercooler and Part of the compressed humidification tower supplied to the combustion chamber Recycle gas less than 50%, preferably less than 40% and in particular preferably in the range from 20 to 30% of the total compressed recycle gas to be located downstream of the compressor.

Another preferred embodiment of the The present invention is characterized in that the resulting in the intercooler waste heat for the Humidification is used in the humidification tower. So can be used for humidification required enthalpy efficiently obtained from the intercooler become. Process water in the intercooler is particularly preferred, respectively Process steam heated, and this hot process water in the humidification tower for humidification used. This process water or process steam can particularly preferred when introduced into the humidification tower Have temperature in the range of 150 to 250 degrees Celsius at a pressure which is essentially the inlet pressure of the Corresponds to gas turbine, i.e. e.g. from in the range of 10 to 35 bar. As in the intercooler Process water used can condense out of the circulating gas Water and / or preheated Process water from an air separation plant, and / or preheated process water from a unit for removing carbon dioxide and / or water, and / or preheated Process water, which is at least indirectly with a condenser for the Recycle gases and / or residual water from the intercooler can be used. The Use of water already available in the cycle shows the great advantage that water is used automatically, which is the degree of purity required for long-term operation having. Otherwise it is when injecting water mostly required this either with additives too provided to prevent deposits, or deionized To use water. This is associated with considerable costs can be avoided in this way.

A further increase in the flexibility of the driving style can acc. another preferred embodiment thereby achieved be that in addition Steam generated in the waste heat boiler is introduced before or into the combustion chamber is, preferably this steam in the waste heat boiler gradually first in an economizer, then in an evaporator with the help a steam drum and then generated in a superheater. The Injection of steam increased on the one hand the mass flow in the gas turbine and reduced on the other hand, the temperature in the combustion chamber. Both has the consequence that the available Performance on the gas turbine increased can be. It proves to be advantageous to additionally in the combustion chamber injected steam flow less than 20 mass% respectively. 30 vol% of the total compressed gas flows to the combustion chamber to let, the steam flow being particularly preferred in the range from 10 to 30 mass% respectively. Accounts for 20 to 40 vol% of these gas flows.

According to another preferred embodiment The invention is used to humidify the circulating gas in the humidification tower Water and / or steam used, which has been preheated in the waste heat boiler, taking this preheating preferably in stages at first done in an economizer and then an evaporator, and being this water or steam is particularly preferred when discharged in the humidification tower a temperature in the range of 150 to Have 250 degrees Celsius at a pressure that is essentially corresponds to the inlet pressure of the gas turbine, i.e. e.g. from in the area from 10 to 35 bar. In this embodiment, the im Heat from the waste heat boiler used for to provide the humidification required enthalpy. In particular in combination with process water that has already been heated in the intercooler, can ensure a very efficient process with high efficiency become. Here too, as already mentioned above, it proves to be the case on deposits as advantageous, essentially exclusively Water condensed from the recycle gas for humidification in the humidification tower respectively for to use steam injection in the combustion chamber.

Another preferred embodiment is characterized in that the humidified circulating gas downstream the humidification tower in the waste heat boiler, preferably in a superheater stage, is further heated before being introduced into the combustion chamber, the Recycle gas after overheating particularly preferably a temperature in the range from 500 to Have 650 degrees Celsius at a pressure that is essentially corresponds to the inlet pressure of the gas turbine, i.e. e.g. from in the area from 10 to 35 bar. This "reheating" in a superheater stage can be used for this to further improve efficiency. Here again the flexibility the system thereby increased that the circulating gas flow, which is downstream of the humidification tower to disposal is divided in a controllable manner into two partial streams, the one is fed directly to the combustion chamber, and the other via the called superheater level heated further in the waste heat boiler and only then fed to the combustion chamber. Especially in combination with the adjustable direct feeding of Circulating gas immediately behind the compressor in the combustion chamber and with the additional adjustable injection of steam The process can be optimally carried out from the waste heat boiler into the combustion chamber adjust, especially with regard to efficiency for components that are for conventional operation are designed.

According to another embodiment The invention is downstream of the intercooler and before the humidification tower a partial flow of the compressed circulating gases is branched off and one Unit fed, in which carbon dioxide and / or water is removed from the recycle gas become. The fact that this branch takes place behind the intercooler by branching off into the carbon dioxide separation unit and water lost heat be greatly reduced. This partial stream preferably makes less than 20% by mass, particularly preferably less than 15% by mass of the total circulating current.

Another preferred embodiment is characterized in that to reduce the compression work also the recycle gas in an intercooler or by water injection chilled is, with particular preference when using an intercooler the resulting waste heat used at least indirectly for humidification in the humidification tower becomes.

Basically come for the provision of pure oxygen different processes in question. Usually the oxygen used in the combustion chamber is separated Air separation plant provided. That can change with the Air separation plant around a cryogenic, an absorptive or a Act membrane-based air separation plant. Alternatively, however the oxygen used in the combustion chamber is also integrated Membrane module available be put.

Further preferred embodiments of the invention Procedures are in the dependent claims described.

In addition, the present invention relates to an apparatus for performing a method as described above. The device comprises a semi-closed CO ₂ process, at least one compressor being arranged, by means of which recycle gas is compressed, this compressed recycle gas is fed to a gas turbine after passing through a combustion chamber, and a waste heat boiler is arranged, in which the exhaust gases in the expanded gases are released Residual heat contained behind the gas turbine is used to generate steam and / or hot water. In particular, means are arranged via which a first part of the compressed recycle gas is fed directly to the combustion chamber, and an intercooler is arranged in which a second part of the compressed recycle gas is cooled before being introduced into the combustion chamber and a humidification tower is also arranged in which the cooled compressed recycle gas is humidified before introduction into the combustion chamber.

Further preferred embodiments the inventive Device are in the dependent claims described.

SHORT EXPLANATION THE INVENTION

The invention is based on Embodiments are explained in connection with the figures. Show it:

1 a schematic of an emission-free gas turbine power plant with bottoming steam turbine according to the known prior art;

2 a schematic of an emission-free gas turbine power plant with topping steam turbine according to the known prior art;

3 a diagram of an emission-free gas turbine power plant with intermediate cooling and humidification and

4 a diagram of another emission-free gas turbine power plant with intermediate cooling and humidification of a partial flow of the compressed air and steam injection.

WAYS TO EXECUTE THE INVENTION

1 shows as a known prior art a schematic representation of a semi-closed gas turbine system with waste heat boiler 4 and steam turbine 10 , The system has a compressor 1 , which compresses the working medium (circulating gas). The compressed recycle gas 48 is then in a combustion chamber 2 led, fuel is burned there and the hot circulating gases then in a turbine 3 relaxes and the generated mechanical energy with a generator 8th used to generate electrical energy. The fuel is fed through a fuel line 20 fed. Essentially pure oxygen is used as the oxidizing agent, which is used in an air separation plant 9 made available and via a line 21 is fed. At the air separation plant 9 can be a system according to the state of the art. So come z. B. Methods such as cryogenic separation, pressure swing absorption (PSA) in question, but it is also possible instead of a separate air separation plant 9 to use an integrated membrane reactor. The air separation plant 9 is over a line 34 supplied with fresh air and usually has at least one cooler, among other things 12 , at which waste heat is generated, which is usually of low value (low temperature).

The hot exhaust gases from the gas turbine 3 are on a line 23 a waste heat boiler 4 fed where the residual heat contained in the exhaust gases is used. In the counter-rotating principle in this waste heat boiler 4 Water first in an economizer 26 warmed, then in an evaporator 28 with the help of a steam drum 27 evaporated and finally in a superheater 29 heated further. The water circuit is powered by a pump 25 powered and in a feed water tank 24 the process water is kept ready or, if necessary, degassed. That in the waste heat boiler 4 heated, vaporous water is then a condensing steam turbine 10 fed, and relaxed in this. Thereby a generator 11 driven. Behind the steam turbine 10 the steam becomes a condenser 30 fed, and the condensed process water via a pump 31 again in the feed water tank 24 promoted.

The one in the waste heat boiler 4 cooled circulating gas flow is behind the waste heat boiler 4 a cooler or condenser 5 fed. The circulating gas is essentially a mixture of carbon dioxide and water, that is, it consists of a mixture of the reaction products of the combustion of e.g. B. natural gas with oxygen. Correspondingly condenses in the condenser 5 Water out, and this is through a drain line 33 dissipated. The circulating gas is behind the condenser 5 again the compressor 1 fed.

A part 49 of the compressed recycle gas 48 is behind the compressor 1 fed via a line to a unit in which both water and carbon dioxide are removed from the system. This unit has a first cooler 7a , in which essentially water is condensed out. This water is piped 33 removed from the system. Behind the first cooler 7a this proportion of the recycle gas in a compressor 6 further compressed and in a second cooler 7b water is then condensed out again, but also carbon dioxide, which is fed via a line 32 is removed from the system. The carbon dioxide can then be disposed of properly.

At the in 1 shown system is a semi-closed, emission-free, combined circuit with gas turbine, waste heat boiler and steam turbine. The steam turbine is usually referred to as a bottoming steam turbine. The waste heat contained in the hot exhaust gases from the gas turbine is used in the waste heat boiler to generate steam for the steam turbine.

A disadvantage of such a structure is, among other things, the fact that a comparatively large amount of waste heat is generated by branching off a partial stream 49 is lost for separation. The overall efficiency of the system is reduced by this process control.

2 shows a corresponding semi-closed, emission-free system, in which the in the hot exhaust gases 23 the waste heat contained in the gas turbine is not in a separate steam cycle as in 1 is used, but rather is used to generate steam, which is initially via a back pressure steam turbine 35 (so-called topping steam turbine) is relaxed. The steam is released in the turbine 50 on a generator 11 generates electrical energy. Downstream of the steam turbine 50 the steam is then either in front of or in the combustion chamber 2 the compressed recycle gas 48 fed. The supply of steam to the circulating gas increases the mass flow and thus the output from the gas turbine, respectively the generator 8th can be generated. Also in connection with a structure according to 2 (Known prior art), however, the above-mentioned problem arises that here too by the branched-off partial stream 49 relatively much heat is removed from the system unused, which lowers the efficiency.

The problems mentioned can be avoided by a procedure known as conventional humid air turbine for conventional open gas turbine systems. An embodiment of such a method is in 3 shown.

The gas flow 37 (Recycle gas) consists essentially of carbon dioxide (CO ₂ ) and water (H ₂ O) and small proportions of other components. In the compressor 1 becomes the recycle gas up to the working pressure of the gas turbine 3 compressed. The hot gas stream 48 is then in an intercooler 47 cooled by heat on through the intercooler 47 water is transferred.

Downstream of the intercooler 47 the compressed recycle gas is divided, with a large part via the line 44 a humidification tower 46 is supplied (usually more than 80%), and a smaller proportion via the line 43 a unit for separation is fed. In this unit, the gas is first passed through a condenser 7a passed in which essentially all of the water is condensed out of the gas. The water is then piped 33 either removed from the system or made available for further use within the system. Behind the first condenser 7a the gas, which essentially consists only of carbon dioxide, is in a compressor 6 further compressed and in a second capacitor 7b further compressed. A little water is condensed out again via the line 33 dissipated, and the resulting carbon dioxide is on the line 32 either disposed of or otherwise used. The one in the two capacitors 7 Waste heat removed from the gas can be transferred via heat exchangers 42 be fed to a process water flow. This warm water, which is usually at a temperature of 60 to 100 degrees Celsius, can be used in other processes within the system (see below).

In the humidification tower 46 the main part of the circulating gas is moistened with water or steam as much as possible. Usually the gas flow 40 saturated with water behind the humidification tower. Care is taken to ensure that the enthalpy required for the evaporation of the water is essentially provided by the water, ie that the water is supplied for humidification at the highest possible temperature. The water used for humidification comes from the intercooler on one side 47 , That in the intercooler 47 Process water used to cool the circulating gas is at an elevated temperature and can therefore be used directly in the humidification tower with optimal use of the heat. Alternatively or additionally, the humidification tower 46 Water supplied from the waste heat boiler 4 comes. In this way, heat that is in the intercooler 47 and in the waste heat boiler 4 is optimally used for the evaporation process and the humidification of the recycle gas leads to an increase in the mass flow in the gas turbine with the associated increase in output.

Excess water from the humidification tower 46 is about the line 45 dissipated and either the entrance of the waste heat boiler 4 fed or the input of the intercooler 47 , Water which is at least slightly warmed is preferably used as the process water for the heat exchange in the intercooler. This includes water from the air separation process 9 (e.g. water with comparatively low-quality heat from a cooler 12 ), Water from the separation unit, ie water from the heat exchangers 42 , or from a heat exchanger 42 which is a capacitor 5 is connected downstream for the recycle gas.

Downstream of the humidification tower 46 becomes the saturated recycle gas 40 in a superheater stage 29 (Recuperator stage) in the waste heat boiler 4 heated further. Temperatures will usually be in the range from 500 to 650 degrees Celsius at a pressure which essentially corresponds to the inlet pressure of the gas turbine, ie for example in the range from 10 to 35 bar. This heated and humidified circulating gas then becomes the combustion chamber 2 fed. The humidification of the circulating gas leads to an increase in the mass flow through the gas turbine due to the added water and thus also to an increase in the achievable output at the same temperature in the combustion chamber or at the same turbine inlet temperature.

Also the combustion chamber 2 oxygen is supplied 21 from an air separation plant 9 as well as fuel via a line 20 , The fuel is preferably natural gas, but it can also be liquid fuels. The combustion is adjusted by regulating fuel and oxygen in such a way that essentially all of the supplied oxygen is used and downstream of the gas turbine 3 essentially no more oxygen is present in the recycle gas. The tributaries 20 . 21 . 40 to the combustion chamber 2 are regulated in such a way that the required power output of the gas turbine is set and that the temperature of the hot combustion gases in the combustion chamber 2 and the relaxed hot combustion gases 39 behind the gas turbine 3 do not become so high that thermally particularly stressed parts are heated up over the masses. Of course, such particularly thermally stressed parts can be cooled by additional cooling (e.g. Film cooling or steam cooling). These additional cooling options are in 3 but not shown. Basically, for such cooling, however, gas flows or steam flows with a low temperature come into question, as z. B. behind the intercooler 47 or occur elsewhere.

The hot combustion gases 38 are behind the combustion chamber 2 a turbine 3 fed, and relaxed in it. The mechanical energy generated is in a generator 8th converted into electrical energy. Behind the gas turbine 3 become the relaxed hot combustion gases 39 in a waste heat boiler 4 used in the countercurrent principle for heating water or steam, as already described above. The cooled recycle gas is behind the waste heat boiler 4 in a capacitor 5 cooled, at the same time the main part of the water condenses and via the line 33 is dissipated. That over the line 33 Whenever possible, drained water is reused as process water in the cycle. The advantage here is that the water condensed out of the circulating gas is essentially free of impurities and minerals, which, if introduced into the circulating gas, could possibly lead to deposits or soiling. While in the case of a water injection it is usually necessary to take care to either add additives to the water or to clean or deionize it, relatively clean water is provided directly by the process itself, which considerably simplifies cleaning. Behind the condenser 5 the recycle gas is in turn piped 37 the input of the compressor 1 fed.

Compared to the driving style according to the prior art, the proposed process has the great advantage that the circulating gas flow before the branch 43 for separation in an intercooler 47 is cooled down and that the waste heat accrues to the process in the humidification tower 46 is fed again. So it can through the junction 43 Resulting energy loss can be reduced by at least 2/3 compared to the conventional driving style, as z. Tie 1 and 2 is shown. In addition, the temperature of the circulating gases at the outlet of the waste heat boiler can be reduced further than when using a conventional steam generator.

Basically, the procedure allows one versus using a bottoming or one topping steam turbine much cheaper solution with comparable efficiency (A waste heat boiler and a humidification tower are comparative cheap components and also not very sensitive). Furthermore the proposed method has the advantage in comparison to be easier to adjust for the use of further steam turbines, d. H. the optimal efficiency can also be changed among the Conditions of a semi-closed carbon dioxide / water cycle still adjust well.

Alternatively, a further increase in efficiency can optionally be carried out downstream of the superheater in the line 40 a steam turbine can be arranged (see topping steam turbine).

A further increased flexibility of such a process can be achieved in that new paths are made available for the compressed recycle gas, and in particular that the different paths are designed in a controllable manner. This is for another embodiment in 4 shown. It is essentially a structure according to 3 , but here is the hot compressed circulating gas flow downstream of the compressor 1 divided into two sub-streams. A first partial flow 50 is directly and without further cooling or humidification of the combustion chamber 2 fed. The second partial flow 48a is essentially based on the procedure 3 accordingly an intercooler 47 fed and then a humidification tower 46 , Again, between intercoolers 47 and humidification tower 46 a part 43 of the circulating gas branched off by this portion through condensation of the water and carbon dioxide contained in the end via the lines 33 respectively remove 32 from the system. Behind the humidification tower 46 the compressed and humidified recycle gas is again divided into two partial streams as an option. Either the saturated gas flow 40 a superheater stage 29 in the waste heat boiler 4 fed and then into the combustion chamber 2 directed. Or there is no further overheating and the saturated gas flow is directly over the path 51 the combustion chamber 2 fed. While usually the path 40 (respectively 52 ) with overheating allows better process efficiency, it turns out that the direct initiation 51 into the combustion chamber 2 allows a higher maximum performance. Accordingly, the balance of the two paths 40 respectively 52 and 51 can be set according to these criteria.

Another difference to the process according to 3 is that the evaporator stage 28 in combination with the subsequent superheater stage 29 an additional steam path is now also used in this process control 53 to open up the combustion chamber 2 allowed to apply steam. The steam can either be introduced into the combustion chamber or else upstream or downstream of the combustion chamber. This supply of steam 53 to the combustion chamber in turn allows the mass flow through the gas turbine 3 to increase.

Here, too, it is possible to increase the efficiency in the line 53 To generate steam, the pressure of which is substantially above the operating pressure of the gas turbine 3 lies. Corresponding can then be on the line 53 a topping steam turbine, in 4 not shown) can be installed, via which the steam is expanded and with which an additional generator can be driven. Of course, that can be on the line 53 respectively in the area of the steam generator 27 The steam made available can also be used, at least in part, in other processes (so-called co-generation).

Essential in connection with the procedure according to 4 is now among other things that the different paths 48a . 50 . 41 . 52 . 53 to the combustion chamber 2 all are available in a controllable manner. Accordingly, it is possible without design changes to the individual components such as waste heat boilers 4 , Humidification tower 46 or intercooler 47 (In other words, standard components from the field of conventional gas turbine systems can be used without any problems) to run a semi-closed, emission-free process with high efficiency. Basically, these different paths are set so that the desired power level on the generator 8th is reached and that the temperatures in the combustion chamber 2 , in the gas turbine 3 as well as in the path 39 do not exceed critical values.

The following specific values can be given as an example for the water and steam flows, based on a constant compressor mass flow:
Steam flow in the superheater 29 : 15-25%
Mass flow ( 40 + 51 - 44 ) in the humidifier 46 : 0–7.5%
mass flow 50 : 65-85%
mass flow 44 : 0–25%
mass flow 43 : 10-15%

This process delivers

• - 5–10% more power than a process according to the scheme 2 at approx. 1% better efficiency,
• - 35–70% more performance than a process according to the scheme 1 at approx. 2.5–3.5 lower efficiency and
• - 20–55% more power than a process according to the scheme 3 at approx. 1.5–2.5% poorer efficiency.

Of course, the invention is not limited to the exemplary embodiments described. As an option, it is possible to use the cooler 47 omit, and thus supply the circulating gases to the humidification tower uncooled.

1

compressor

2

combustion chamber

3

turbine

4

waste heat boiler

5

Cooler, condenser

6

compressor

7a, b

cooler

8th

generator

9

Air separation plant

10

Condensing steam turbine

11

generator

12

cooler

20

fuel supply

21

oxygen supply

22

wave

23

management to the waste heat boiler

24

Feedwater tank

25

pump

26

economizer

27

steam drum

28

Evaporator

29

superheater (Recuperator)

30

capacitor

31

water heater

32

discharge for carbon dioxide

33

discharge for water

34

Fresh air

35

Backpressure steam turbine

36

steam injection in front of the combustion chamber

37

Return to compressor

38

name is combustion gases

39

relaxed hot combustion gases

40

saturated gas flow

41

water

42

heat exchangers

43

compressed Gases (discharged Proportion of)

44

compressed Gases (portion to be humidified)

45

residual water

46

humidifying

47

intercooler

48

compressed recycle gas

48a

compressed Recycle gas, indirect partial flow

49

diverted Partial flow of the recycle gas for separation

50

direct partial flow

51

saturated Gas flow without overheating

52

saturated Gas flow with overheating

53

additional Steam path (injection before, in or behind the combustion chamber)

Claims (13)

Method for operating a power plant with a semi-closed CO ₂ process, at least one compressor ( 1 ) is arranged, by which recycle gas is compressed, this compressed recycle gas ( 48 ) after passing through a combustion chamber ( 2 ) a gas turbine ( 3 ) is supplied, and wherein a waste heat boiler ( 4 ) is arranged, in which the in the relaxed exhaust gases ( 23 . 39 ) contained residual heat behind the gas turbine ( 3 ) for generating steam and / or hot water is used, characterized in that a first part ( 50 ) of the compressed recycle gas directly to the combustion chamber ( 2 ) is fed, and a second part ( 48a ) of the compressed recycle gas before it is introduced into the combustion chamber ( 2 ) in an intercooler ( 47 ) is cooled and then before being introduced into the combustion chamber ( 2 ) in a humidification tower ( 46 ) is moistened. A method according to claim 1, characterized in that the second part ( 48a ) of the compressed recycle gas less than 50%, preferably less than 40%, and particularly preferably in the range from 20 to 30% of the total compressed recycle gas downstream of the compressor ( 1 ) matters. Method according to one of the preceding claims, characterized in that the in the intercooler ( 47 ) waste heat for humidification in the humidification tower ( 46 ) is used, preferably in the intercooler ( 47 ) Process water is heated, and this hot process water in the humidification tower ( 46 ) is used for humidification, this process water or process steam being particularly preferred when it is introduced into the humidification tower ( 46 ) has a temperature in the range of 150 to 250 degrees Celsius at a pressure which essentially corresponds to the inlet pressure of the gas turbine. A method according to claim 3, characterized in that as process water in the intercooler ( 47 ) water condensed from the recycle gas ( 33 ) and / or preheated process water from an air separation plant ( 9 ), and / or preheated process water from one unit ( 6 . 7 . 42 ) to remove carbon dioxide ( 32 ) and / or water ( 33 ), and / or preheated process water, which is at least indirectly used in a condenser ( 5 ) for the circulating gases and / or residual water ( 45 ) from the intercooler ( 47 ), is used. Method according to one of the preceding claims, characterized in that for humidifying the circulating gas in the humidification tower ( 46 ) Water and / or steam is used, which is in the waste heat boiler ( 4 ) was preheated, this preheating in an economizer ( 26 ), and this water or steam is particularly preferred when it is introduced into the humidification tower ( 46 ) has a temperature in the range of 150 to 250 degrees Celsius at a pressure which essentially corresponds to the inlet pressure of the gas turbine. Method according to one of the preceding claims, characterized in that in addition in the waste heat boiler ( 4 ) Steam is generated, which via a steam path ( 53 ) in front of, behind or into the combustion chamber ( 2 ) is introduced, preferably this steam in the waste heat boiler ( 4 ) gradually in an economizer ( 26 ), then in an evaporator ( 28 ) with the help of a steam drum ( 27 ) and then in a superheater ( 29 ) is produced. A method according to claim 6, characterized in that the steam flow ( 53 ) less than 20 mass% resp. 30 vol% of the total compressed, the combustion chamber ( 2 ) supplied gas flows ( 50 - 53 ) matters. Method according to one of the preceding claims, characterized in that essentially exclusively water condensed out of the circulating gas ( 33 ) for humidification in the humidification tower ( 46 ) respectively for steam injection ( 53 ) into the combustion chamber ( 2 ) is used. Method according to one of the preceding claims, characterized in that the humidified circulating gas ( 40 ) downstream of the humidification tower ( 46 ) in the waste heat boiler ( 4 ), preferably in a superheater stage ( 29 ) before introduction into the combustion chamber ( 2 ) is further heated, the circulating gas after the overheating particularly preferably has a temperature in the range from 500 to 650 degrees Celsius at a pressure which essentially corresponds to the inlet pressure of the gas turbine. Method according to one of the preceding claims, characterized in that downstream of the intercooler ( 47 ) and in front of the humidification tower ( 46 ) a partial flow ( 43 ) of the compressed recycle gases and one unit ( 6 . 7 . 42 ) is supplied in which unit carbon dioxide ( 32 ) and / or water ( 33 ) are removed from the recycle gas, this partial stream ( 43 ) makes up less than 20% by mass, particularly preferably less than 15% by mass, of the total circulating stream. Method according to one of the preceding claims, characterized in that, in order to reduce the compression work, the circulating gas is also cooled in an intercooler or by water injection, the waste heat generated in this case being particularly preferably at least indirectly used for humidification in the humidification tower (using an intercooler) 46 ) is used. Method according to one of the preceding claims, characterized in that the in the combustion chamber ( 2 ) used oxygen ( 21 ) in a separate air separation plant ( 9 ) is provided, which is the air separation plant ( 9 ) a cryogenic, an absorptive or a membrane ran based air separation plant ( 9 ) can act, or that in the combustion chamber ( 2 ) used oxygen ( 21 ) is made available in an integrated membrane module. Device for carrying out a method according to one of the preceding claims, wherein the device comprises a semi-closed CO ₂ process, at least one compressor ( 1 ) is arranged, by which recycle gas is compressed, this compressed recycle gas ( 48 ) after passing through a combustion chamber ( 2 ) a gas turbine ( 3 ) is supplied, and wherein a waste heat boiler ( 4 ) is arranged, in which the in the relaxed exhaust gases ( 23 . 39 ) contained residual heat behind the gas turbine ( 3 ) is used to generate steam and / or hot water, characterized in that means are arranged via which a first part ( 50 ) of the compressed recycle gas directly to the combustion chamber ( 2 ) and that an intercooler ( 47 ) is arranged, in which a second part ( 48a ) of the compressed recycle gas before it is introduced into the combustion chamber ( 2 ) is cooled and also a humidification tower ( 46 ) is arranged in which the cooled compressed recycle gas ( 44 ) before introduction into the combustion chamber ( 2 ) is moistened.