DE102008049737A1 - Producing coal, preferably coal slurry from wet biomass, preferably sewage slurry by hydrothermal carbonization, comprises concentrating the biomass by dewatering, adjusting the pH of the biomass and drying the resulting product - Google Patents

Abstract

Producing coal, preferably coal slurry from wet biomass, preferably sewage slurry by hydrothermal carbonization, comprises concentrating the biomass by dewatering to a value of above 10% dry substance portion, prior to the hydrothermal carbonization; adjusting the pH of the biomass to less than 4, prior to the hydrothermal carbonization; and subsequently drying the resulting product by process-waste heat originated from the hydrothermal carbonization, where the carbon structures of the biomass are broken preferably at 180-200[deg] C under airtight. An independent claim is included for an apparatus for carrying out the above method.

Description

The The invention relates to a process for the production of coal from wet Biomass in batch mode by hydrothermal carbonation. Furthermore, the invention relates to a device for performing of the procedure.

The method is based on the hydrothermal carbonization (HTC), as described by Prof. Dr. med. Marcus Antonietti was developed at the Max Planck Institute for Colloids and Interfaces in Potsdam. This was, for example, in the Magazine "MaxPlanckResearch" 2/2006 described.

at the HTC is overflowing at temperatures around 200 ° C 12 hours wet biomass transformed into a coal sludge. This can then be dried and used materially.

The method is used for example in DE 10 2007 012 112 B3 used in a continuous process.

In DE 10 2007 062 809 A1 and in DE 10 2007 012 112 B3 the addition of acids to lower the pH is described as advantageous.

The described methods have some significant disadvantages:
Since the HTC is a hermetically sealed process, the composition of the input materials directly determines the property of the final product. By using moist biomass, in particular biomass residues, there is thus a natural variation in the properties of the end product. If the end product needs to meet minimum re-use requirements, these fluctuations can lead to product dislocations and thus reduce the yield of the process.

So for example B. in the HTC of sewage sludge significant differences in the ratio of the organic and the mineral dry matter proportions on. Accordingly, the calorific value of the dried starting material the calorific value of the HTC is between 10,000 J / g and 25,000 J / g. Become on the other hand food residues can be fed to an HTC Due to the higher carbohydrate content, calorific values between 20,000 J / g and 30,000 J / g. To the starting materials after the HTC must be able to use economically these, however, usually at least the calorific values of lignite which in the dried state has about 20,000 J / g. This is according to the prior art in fluctuating qualities the input materials do not ensure.

The use of a continuous process also has considerable disadvantages for the HTC:
As a result of the simultaneous process steps "mixing / homogenization" and "transport", backmixing occurs in the reaction volume, which leads to a broad residence time spectrum and a poorly defined process sequence. The properties of the product produced are therefore difficult to standardize here.

Of Another is the sealing of a continuous system problematic. The carbonation takes place at high pressures instead, this results in the problem of sealing the material entry and discharge.

Solid accretions on the components can not be prevented and cause the example valves must be switched redundant.

Farther arise during the HTC major technical Problems due to the very different viscosities the input materials. It can thereby high mechanical Loads of transport shafts or agitators occur to the stoppages of material transport. So z. A sewage sludge, which is pre-dried to 30% solids content and because of the contained Hydrocolloids does not have a very high strength without further Addition of water to transport or mix.

Becomes the process by an addition of acid and the associated Reduction of the pH value is supported by the chemical costs significantly higher operating costs. These can cause the equipment for certain biomasses can no longer be operated profitably.

task The invention is biomass with different and fluctuating Properties using the HTC convert into a coal which is a consistent and sufficient quality for subsequent uses having. Furthermore, by the specific use of certain Input materials the operating costs, especially those for adjustment a suitable pH and dry matter content, reduced become.

• – dass die Eingangsstoffe vor jeder Batch charakterisiert werden,
• – dass unterschiedliche Eingangsstoffe vor jeder Batch gezielt gemischt werden,
• – dass der Ausgangsstoff einer jeden Batch oder das Gemisch mehrerer Batchs nach stofflichen Eigenschaften analysiert wird, und
• – dass der Ausgangsstoff einer jeden Batch oder das Gemisch mehrerer Batchs abhängig von den festgestellten Eigenschaften mit dem einer anderen Batch oder Gemischen mehrerer Batchs gezielt vermischt wird.

This object is achieved according to the invention

• - that the input materials are characterized before each batch,
• - that different input materials are mixed specifically before each batch,
• - that the starting material of each batch or the mixture of several batches is analyzed for material properties, and
• - that the starting material of each batch or Depending on the properties determined, the mixture of several batches is mixed in a targeted manner with that of another batch or mixtures of several batches.

• – Durch Mischungen von Eingangsstoffen (z. B. Klärschlamm und Lebensmittelreste) wird die der HTC zugeführte Biomasse in ihren Eigenschaften standardisiert und damit zuverlässig und wiederholbar behandelbar.
• – Das Mischungsverhältnis der Eingangsstoffe wird in der Art eingestellt dass gewünschte Eigenschaften des Ausgangsstoffs, wie z. B. Brennwert oder Aschegehalt, erreicht werden.
• – Durch Beimischung milchsäurebildender Biomasse wie z. B. Grassilage oder Fruchtresten wie z. B. Apfelschalen oder Zitrusfruchtschalen wird der pH Wert des Eingangsstoffgemischs erniedrigt und Chemikalien zur Einstellung des pH Werts eingespart.
• – Das Endprodukt wird durch gezielte Vermischung verschiedener Batches in seinen Eigenschaften vergleichmäßigt und genügt notwendigen Mindestanforderungen zur Weiterverwendung wie z. B. einem minimalen Brennwert.

Such a method leads to the following advantages:

• - Through mixtures of input materials (eg sewage sludge and food residues), the biomass supplied to the HTC is standardized in its properties and thus reliably and repeatedly treatable.
• - The mixing ratio of the input materials is set in the way that desired properties of the starting material, such as. As calorific value or ash content can be achieved.
• - By admixing lactic acid-forming biomass such. As grass silage or fruit residues such. As apple peel or citrus peel, the pH value of the input material mixture is lowered and saved chemicals to adjust the pH value.
• - The end product is made uniform by targeted mixing of different batches in its properties and meets the minimum requirements for re-use such. B. a minimum calorific value.

Especially it is advantageous that the hydrothermal carbonization in the batch process is carried out under very well-defined conditions and the driving style precisely to the respective characteristics the input materials and the desired properties of the Starting material is tuned.

Maximum It is advantageous that in the case of highly viscous starting materials in the batch reactor first stir the material to the reaction temperature without stirring is brought to break down a portion of the hydrocolloids, resulting in a liquefaction of the material leads and the subsequent use of a stirrer without load the mechanics allowed.

substantial Simplification of the drainage of coal sludge after HTC is reached when dry biomass is added to the input material mixture is to increase the dry matter content. this makes possible also a better exothermic reaction and a higher one Amount of heat released during HTC and for subsequent drying available stands.

Maximum advantageous embodiments are in the further subclaims listed.

advantageous exemplary embodiments of the invention The method will be described below. Here, the drawings show a Execution in simple schematic representation.

One Embodiment of the method is in the drawings shown schematically and will be included below Alternatives described.

Different biomasses are characterized in separate storage containers by means of suitable measurement technology ( 1 ). In a subsequent mixing stage ( 2 ), the input material mixture for the HTC is produced according to the desired properties. This z. As orange peels are added to reduce the pH of the input material mixture or dried biomass are mixed to increase the dry matter content of the input material mixture. Likewise, biomass with a high carbohydrate content, such as food residues with biomass with a low carbohydrate content, such as sewage sludge, can be mixed in order to achieve a sufficient calorific value of the end product. Subsequently, the input material mixture can be characterized again ( 3 ). A transport unit ( 4 ), the mixture of HTC to.

In the HTC, the input material (eg sewage sludge, green waste etc.) is homogenized ( 5 ) and, if necessary, subjected to a preliminary separation of inert and impurities. This can be z. In a hydrocyclone ( 6 ) respectively. A hydrocyclone can cause partial drainage. It is then, for example, in a decanter ( 7 ) a mixture of biomass and water produced with a typical solids content of 25% or more. This is optionally preheated by the waste heat of the previous process step (heat of the product). The preheated mixture is added to the reaction vessel ( 8th ) brought. By supplying heat energy, the reactor is brought to a temperature between 160 and 230 ° C. The existing oxygen is expelled in the initial phase by the resulting water vapor. The reactor is then sealed pressure-tight. The required heat energy comes either from a fire ( 9 ) or from a heat storage ( 10 ), which was fed in the previous process step by waste heat from the reaction. The reaction then proceeds with evolution of heat. This heat is used to re-energize the latent heat storage.

After completion of the reaction, the reactor is depressurized to ambient pressure and the generated coal sludge in a storage container ( 11 ) dissipated. The waste heat is used to preheat the next batches. The produced product "coal sludge" can then be dehumidified and dried mechanically or mechanically / thermally ( 12 ).

The use of two reactors in parallel operation ( 8th ) also offers the possibility Reacti Onswärme in the one reactor is free to use directly for the start of another reaction.

The resulting coal is after production according to their essential properties by suitable measuring technology ( 13 Characterized. This can z. As calorific value, ash content or pollutants. The coal is then separated into separate batches ( 14 ) and in a subsequent stage ( 15 ) is mixed with other batches in such a way that the resulting mixture obtains a desired property. This can be, for example, a consistent quality or a minimum quality such. For example, a minimum calorific value of 15,000 J / g. The resulting mixture is then analyzed for its essential properties by means of suitable measuring technology ( 16 ) examined and released.

The final product is then stored in a container for further use ( 17 ).

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102007012112 B3 [0004]
• - DE 102007062809 A1 [0005]
• - DE 102007012112 [0005]

Cited non-patent literature

• - Magazine "MaxPlanckResearch" 2/2006 [0002]

Claims (10)

Process for the production of coal from wet biomass in batch mode by means of hydrothermal carbonization characterized in that - the input materials are characterized before each batch, - that different input materials are mixed before each batch targeted, - that the starting material of each batch or the mixture of several batch after - that the starting material of each batch or the mixture of several batches is intentionally mixed with that of another batch or mixtures of several batches, depending on the characteristics determined, Method according to claim 1, characterized in that that used as input materials different types of biomass become Method according to Claims 1 and 2, characterized that the pH value of the mixture is mixed by at least one of the Biomass species is lowered Method according to claim 2, characterized that the solids content of the mixture by at least one of mixed biomass species is increased Method according to claim 1, characterized in that that the starting materials of individual batches have fluctuating properties, in particular calorific value properties, and have through targeted mixing a desired property, in particular calorific property, of Mixed product is obtained Method according to claim 1, characterized in that that the starting materials of individual batches partly insufficient Have suitability for further uses and through targeted Mixing a sufficient suitability of the mixed product for more Uses is obtained Method according to Claims 1 and 2, characterized that the process parameters depending on the mixing ratio and Properties of input materials adjusted during each batch can be Method according to Claims 1 and 2, characterized that when using sewage sludge as a biomass first a liquefaction of sewage sludge by the Degradation of hydrocolloids is awaited before a stirrer is switched on in the reactor. Method according to Claims 1 and 2, characterized that agitators or others during the hydrothermal Carbonization for mixing the material to be carbonized suitable plant components at the earliest 5 minutes after Start of hydrothermal carbonization of biomass, in particular of sewage sludge, be turned on Device for carrying out the method according to one of the preceding claims