DE102009024536A1 - Efficient operation of a biomass fermentation plant, comprises fermenting a fermentation substrate in a biogas plant and subsequently energetically utilizing the obtained biogases in a combined heat and power unit - Google Patents

Abstract

The method comprises fermenting a fermentation substrate (1) in a biogas plant (A) and subsequently energetically utilizing the obtained biogases in a combined heat and power unit, where the animal and/or plant materials are provided as fermentation substrate. A bioreactor (B) is upstream to the biogas plant for aerobic treatment and hydrolysis of the fermentation substrate. The biomass containing microorganisms is introduced in addition to the atmospheric oxygen (2), where the heat energy originates from the connected combined heat and power unit. The method comprises fermenting a fermentation substrate (1) in a biogas plant (A) and subsequently energetically utilizing the obtained biogases in a combined heat and power unit, where the animal and/or plant materials are provided as fermentation substrate. A bioreactor (B) is upstream to the biogas plant for aerobic treatment and hydrolysis of the fermentation substrate. The biomass containing microorganisms is introduced in addition to the atmospheric oxygen (2), where the heat energy originates from the connected combined heat and power unit and the bacterial biomass (10) from the subsequent processing steps. The fermentation substrate (4) pretreated in the bioreactor, the further fermentation substrate and optionally the concentrated bacterial biomass form an input material for the biogas plant. The fermentation residual remaining in the biogas plant is further processed in the bioreactor under the effect of heat energy during the addition of atmospheric oxygen and biogenic substances as a carbon source. The biomass separation is downstream to the bioreactor in the form of micro-filtration, sedimentation and/or electro-coagulation, where permeate developed during the micro-filtration is introduced again into the bioreactor, the aqueous residual phase is discharged and the biomass is again introduced into the fermentation process such as in the bioreactor and/or the biogas plant. The biomass is optionally subjected to a concentrator in a separator or to a decanter, where the developed liquid phase is discharged and the concentrated bacterial biomass is provided as additional input material for the biogas plant. The heat energy introduced earlier in the fermentation process is provided for the bioreactor of the combined heat and power unit or other energy generating systems e.g. fuel cells.

Description

The The invention relates to a method for the efficient operation of biomass fermentation plants Utilization of accumulating digestate and the improved digestion of the fermentation substrates.

When Input material serve herbal and / or animal substances, preferably aqueous fermentation residues and fermentation substrates, the are partially contaminated with slime particles and high nitrogen and phosphate loads.

The The end product is a biomass that is largely free of pathogens acting microorganisms. She points opposite to the Starting material reduced ammonium and phosphate contents on and has high protein content.

The By phase separation resulting retentate is used to increase efficiency the biogas reactor or to improve the substrate digestion used.

Consequently it is achieved that the overall process becomes more efficient.

residue water (Permeate) are dischargeable or fertilizer in suitable for agriculture.

digestate fall predominantly in agricultural fermentation processes, the food industry and waste management in large Quantities, with a residue-free recovery not yet given is.

State of the art

In Considering steadily rising energy prices, the finite availability fossil fuels and the increasing scarcity of Raw materials and the demand for resource conservation and climate protection the use of regenerative energy sources is steadily gaining in economic, ecological and socio-political relevance.

The Energy production from biomass thus takes an energy policy Special status, as opposed to the use of wind energy and solar energy is baseload.

The Fermentation of agricultural products, waste materials as well renewable raw materials with the aim of producing biogas and its direct use for energy production in combined heat and power plants, Fuel cells and the like or for the substitution of fossil raw materials, for example, by treatment to biomethane and feed in The natural gas network is therefore becoming increasingly important.

The limited availability of suitable starting materials, especially against the background of competition between food commodity and energy industry, requires the need for continuous optimization of the processes, namely the maximization of the gas yield and the increase in methane content, as well as the expansion of the range of possible Feedstocks. The increase in the number of plants and in particular the Plant size and performance and their concentration At certain locations, the industry also faces new challenges with regard to the use or disposal of the resulting waste products.

The Disposal of fermentation residues from biogas production is traditional for decentralized agricultural biogas plants by spreading on the cultivated areas of the environment. The Nutrient contents as well as the present binding forms, which ensure high plant availability, predestine the digestate for such Application. Nutrient and carbon cycle are thereby almost closed. However, this approach has ecological and increasingly also economic disadvantages.

So has been multiplying the problem of several years already Ammonia emission discussed. The by the degradation of the organic Acids caused during the fermentation process Increasing the pH leads to a shift in the equilibrium from dissolved ammonium nitrogen to ammonia, the escapes as gas.

said Emissions must be counteracted with special application techniques become. Furthermore, a corresponding fertilizer needs determination take place, the need-based application of nutrients ensures and the pollution of waters by the Preventing discharge of nutrients.

When additionally problematic is the entry of unwanted Substances. In particular, heavy metals are common Copper and zinc, as well as infectious germs, such as salmonella, Clostridia, phytopathogenic viruses, or even germinable Weed seeds.

The Temporal adjustment of the application to the needs of the agricultural sector Cultures and the prescribed reduction of greenhouse gas emissions requires a storage of digestate, with a storage capacity of at least 6 months is recommended.

In In the context is particularly important to note that untreated fermentation residues often more than 90% water.

substantial Problems from the aforementioned restrictions and boundary conditions therefore arise in particular for the increasing number of larger, industrial biogas plants.

a Part of these problems is the digestate treatment encountered. The goals are to reduce the quantities and thus the storage and application costs, continue to reduce the environmental impact, namely the release of climate-relevant gases, etc., as well including the separation of nutrients their transfer into a transportable and salable Shape.

typically, individually or in combination used methods are the mechanical separation, thermal processes (drying, evaporation) and method for the treatment of liquid phases (membrane method, aerobic wastewater treatment).

The These methods are associated with some expensive technology and can generate significant investment and operating costs cause. In addition, some of the procedures lead, for example the use of dried fermentation residues as substitute fuel, for Withdrawal of raw materials and nutrients from the material cycle.

In a process for the treatment of organic residues from biogas plants DE 10 2007 004 892 The same are subjected to a mechanical treatment. A first part of the digestate is subsequently evaporated for the production of topical fertilizer while a second part of the thickened digestate is dried for the production of topical fertilizer.

In another method for the conversion of biomass to biogas in anaerobic fermenters according to DE 10 2007 037 202 the digestate is subjected to a solid-liquid phase separation and subjected to the separated solid phase of a thermal pressure hydrolysis. The thus treated solid phase is subjected to a further fermentation process.

In a process for the conversion of highly contaminated nitrogenous waters from fermentation plants into proteinaceous and fatty biomass on a microbial basis DE 10 2008 045 214.9 , energy-depleted waters from fermentation processes with high nitrogen concentrations are converted into protein-containing biomass by means of aerobic assimilation. Optionally existing slimy components are dissolvable. The protein-containing biomass is separated into a thickened and a thin phase, wherein the thickened phase of a material and / or energetic utilization is available and the thin phase is discharged and / or fed to a preceding fermentation process as recirculate. Certain process conditions must be observed.

This The invention closest to the invention is in appreciation the rest of the relevant prior art further developed with a view to improving the efficiency of the above-mentioned Fermentation processes in each industry and agriculture. The in the different fermentation processes accumulating ammonium-containing residues are intended for meaningful recovery be supplied. The problematic disposal, for example by landfilling, diluting, stripping or burning, would be largely eliminated.

task

task The invention is the development of a method for aerobic treatment of strongly ammonium-containing fermentation residues and fermentation substrates using microorganism populations, the due to their ability to add ammonium at additional Administration of external carbon sources are heterotrophic to assimilate. The main goals are shortening the overall process, increasing the methane content in the Biogas and the reduction of fermentation substrate amount.

The Fermentation residues or fermentation substrates have high residual carbon contents and / or they are by their problematic composition and consistency characterized, for Example by a high water content, a high proportion of colloidal dissolved substances or high levels of residual gases or strippbaren Compounds, especially ammonia.

Consequently biogenic residues, which are produced in excess and / or can not be used otherwise, or barely meaningfully, be processable. These are, for example, residues food processing, feed production or the Production of alternative fuels.

Subject of the invention

The inventive task is specified with the in claim 1 Characteristics have been solved. The subordinate claims contain expedient embodiments.

Known Methods of fermentation of fermentation substrate usually include the technical components mixing treatment and hydrolysis, fermentation in biogas plants and energetic use of biogas, for example in a combined heat and power plant.

According to the invention proposed, the carbon source-containing fermentation substrate, further Atmospheric oxygen and microorganisms with the addition of Heat, a first bioreactor for aerobic treatment and To supply hydrolysis. As a carbon source are suitable Residues from the food or feed production, such from farms, from producers of alternative Fuels, from waste collectors etc ..

warmth makes sense from the cogeneration plant or a fuel cell is made available.

By the hydrolysis reactions taking place increase the protein and fat content of the fermentation substrate. The recovered pretreated Fermentation substrate then fermented in a Biogas plant, in one or two stages under accelerated and increased methane gas formation.

The biogas is usually a cogeneration plant or fed to a fuel cell and there in electrical energy and heat, with the heat, as already mentioned, is supplied to the first bioreactor. Furthermore, it is available downstream process steps.

In the biogas plant remains a fermentation residue, the Mucus components, nitrogen and phosphate in relative high doses and pathogenic microorganisms.

To the discharge from the biogas plant is this digestate another downstream second bioreactor for aerobic treatment fed as input material and there under the action of heat further processed. The heat comes from the combined heat and power plant or the fuel cell.

Farther are atmospheric oxygen and a carbon source as aggregate components added. The carbon sources can be the same as in the Be the main method.

By the aggregates form reinforced under aerobic conditions probiotic and largely antitoxic acting microorganisms. These neutralize the originally contained pathogens Microorganisms. Furthermore, the mucus components dissolve on. The mentioned input material is used in the decomposition of ammonium and Phosphate converted into proteinaceous and fatty biomass.

These Biomass is in a further step of biomass separation subjected. Suitable means for this are microfiltration, sedimentation and electrocoagulation. The result of microfiltration Permeate is then returned to the second bioreactor fed or discharged.

Further Products from the biomass separation are an aqueous Residual phase and a strong bacterial biomass. While the aqueous residual phase depending on their Composition and its nutrient content in receiving waters can be introduced or used by agricultural enterprises can, is the biomass as input material of the first bioreactor and / or the biogas plant available.

The Bacterial biomass can continue in a separator or decanter be concentrated. The resulting liquid phase becomes like the aqueous residual phase from the biomass separation used. The concentrated bacterial biomass serves as input material for the biogas plant.

The According to the invention obtained bacterial biomass and the concentrated bacterial biomass thus improve the initial conditions for the reactions in the first bioreactor and in the biogas plant. The efficiency of the overall process increases noticeably.

embodiment

The invention will be described below with reference to a block diagram ( 1 ) explained in more detail. This represents the process-side integration of the method steps according to the invention into a fermentation process for plant or animal fermentation substrates originating from agricultural enterprises, food processing companies, feed manufacturers, alternative fuel producers, waste disposal and the like.

The fermentation substrates 1 are fed directly and / or indirectly to a one or two-stage biogas plant A. The indirect route via a bioreactor B for aerobic treatment and hydrolysis. In the bioreactor B in addition to atmospheric oxygen 2 , Microorganisms and heat energy 3 introduced. The heat energy 3 is provided by the connected combined heat and power plant C. The microorganisms are in large numbers in a process-derived bacterial biomass 10 contain. The carbon source used are the fermentation substrates used 1 ,

An intensive mixing process and the hydrolysis reactions that take place increase the protein and fat content of the mixture. The bioreactor B leaves a pretreated fermentation substrate 4 ,

Together with the already mentioned fermenter substratum 1 and the bacterial biomass 4 this forms the input material for the biogas plant A.

The resulting biogas 5 is fed to a downstream combined heat and power plant C and there in electrical energy and heat energy 3 transformed.

In the biogas plant A remains a digestate 6 containing mucus components, nitrogen and phosphate in relatively high doses and pathogenic microorganisms. The digestate 6 is in another bioreactor D under the action of heat and addition of atmospheric oxygen 2 and biogenic residues 7 further processed as carbon source. The heat energy 3 comes from the combined heat and power plant C. As a carbon source or biogenic residues 7 find the use mentioned above.

in the Bioreactor D form reinforced under aerobic conditions probiotic and anti-toxic microorganisms. Neutralize these the originally contained pathogenic microorganisms much as possible. Furthermore, the mucus components dissolve on.

The Bioreactor D leaves a proteinaceous and fatty biomass.

This is followed by a further processing stage, namely a biomass separation E. For microfiltration, sedimentation and electrocoagulation can be used. The permeate produced during microfiltration 8th is reintroduced into bioreactor D.

Further products from biomass separation E are an aqueous residual phase 9 and a biomass 10 , The aqueous residual phase 9 is discharged into receiving waters or made available to farms. The biomass 10 is reintroduced into the fermentation process, in the bioreactor B and / or in the biogas plant A.

Optionally, the biomass 10 a concentration F in a separator or a decanter. The resulting liquid phase 11 becomes like the aqueous residual phase 9 used from the biomass separation F. The concentrated bacterial biomass 12 serves as input material for the biogas plant A.

1

fermentation substrate,

2

Atmospheric oxygen,

3

Thermal energy,

4

pretreated fermentation substrate,

5

biogas,

6

digestate

7

biogenic Residues,

8th

permeate

9

aqueous Residual phase,

10

biomass,

11

Liquid phase,

12

concentrated Bacterial biomass,

A

Biogas plant,

B

bioreactor

C

CHP,

D

bioreactor

e

Biomass separation,

F

Concentration.

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 102007004892 [0022]
• - DE 102007037202 [0023]
• - DE 102008045214 [0024]

Claims (2)

Process for the efficient operation of biomass fermentation plants with the process steps fermentation in a biogas plant (A) and subsequent energetic use of the obtained biogas ( 5 ) in a combined heat and power plant (C), whereby as fermentation substrate ( 1 ) are available, characterized in that the biogas plant (A) a bioreactor (B) for the aerobic treatment and hydrolysis of fermentation substrate ( 1 ) and that in this additional atmospheric oxygen ( 2 ), Microorganism-containing biomass ( 10 ) and thermal energy ( 3 ), the heat energy ( 3 ) from the connected combined heat and power plant (C) and the bacterial biomass ( 10 ) from subsequent process steps, that the fermentation substrate pretreated in the bioreactor (B) ( 4 ), further fermentation substrate ( 1 ), Biomass ( 10 ) and optionally concentrated bacterial biomass ( 12 ) form the input material for the biogas plant (A), that the digestate remaining in the biogas plant (A) ( 6 ) in a bioreactor (D) under the action of thermal energy ( 3 ) with the addition of atmospheric oxygen ( 2 ) as well as biogenic residues ( 7 ) is further processed as a carbon source, that the bioreactor (D) is a biomass separation (E) in the form of a microfiltration, sedimentation and / or electrocoagulation downstream, wherein the resulting during microfiltration permeate ( 8th ) is reintroduced into the bioreactor (D), the aqueous residual phase ( 9 ) and the biomass ( 10 ) is reintroduced into the fermentation process, namely into the bioreactor (B) and / or into the biogas plant (A), that the biomass ( 10 ) is optionally subjected to a concentration (F) in a separator or a decanter, wherein the resulting liquid phase ( 11 ) and the concentrated bacterial biomass ( 12 ) is available as additional input material for the biogas plant (A). A method according to claim 1, characterized in that the introduced at the beginning of the fermentation process heat energy ( 3 ) and the heat energy ( 3 ) for the bioreactor (D) from the cogeneration plant (C) or another power generation plant, such as a fuel cell, is provided.