AT520801A1 - Process for the utilization of biomass - Google Patents

Abstract

In a process for utilizing cellulosic biomass, e.g. Wood chips, shredded shrubs, kelp or bamboo, comprising the digestion of the cellulosic biomass, enzymes used to digest the biomass and / or chemical compounds are microbiologically prepared in situ by aerobic microorganisms.

Description

The invention relates to a process for the utilization of cellulosic biomass, e.g. Wood chips, shredded shrubs, kelp or bamboo, comprising the digestion of the cellulosic biomass.

There is an intensive search for solutions worldwide to make fuel and raw material supply more sustainable and based on renewable raw materials. A key problem with the use of renewable raw materials is the efficient and cost-effective digestion of vegetable, in particular cellulosic and lignocellulosic ("woody") raw materials.

Plant raw materials are conceivably unsuitable for use, since they are very difficult to access for bacterial anaerobic hydrolysis, as occurs, for example, in a biogas fermenter. Preceding digestion allows the polymeric natural products to be hydrolyzed and recovered much more quickly. The efficiency and efficiency of the digestion have a significant impact on the residence time of the biomass in the reactor and the yield of biogas, for example, and thus on investment and operating costs.

Lignocellulosic raw materials essentially consist of bundled cellulose fibers embedded in a matrix of lignin molecules. The lignin is responsible for the strength of the raw material as support material and hardened polymer, while the stored cellulose fibers ensure the tensile strength. In addition, lignin serves as protection against the penetration of water into the cell wall material.

Lignocellulosic raw materials must accordingly be digested, i. the lignin matrix must be dissolved and the cellulose exposed accordingly and incorporated into its components (glucose, cellobiose and cello-

Oligosaccharide) decomposed or split to. these for various processes following the digestion, e.g. in biogas production processes.

According to the state of the art, for example, organic solvents (eg Organosolv processes), acids (eg digestion and saccharification with sulfuric acid), ammonia (eg AFEX process, ammonia fiber explosion), energy (steam, pressure) but also enzymes are used for the digestion of vegetable raw materials ,

The pulping processes mentioned above have their origins mainly in the pulp and paper industry. A disadvantage of these methods are high operating and installation costs, which are due to the fact that a number of chemicals is used and accordingly technology for chemical regeneration or wastewater and exhaust air purification is needed or a high energy input is necessary because the process under steam or pressure takes place. In addition, the addition of enzymes, which accelerate the digestion of vegetable raw materials, may be necessary.

The present invention therefore aims to provide a method in which the addition of the digestion chemicals and the like can be dispensed with and a moderate energy input can be used.

To achieve this object, the invention consists in a method of the type mentioned essentially in that for the digestion of the biomass used enzymes and / or chemical compounds by aerobic

Microorganisms are produced in situ microbiologically.

The digestion of vegetable and maritime raw materials, valuables and waste materials takes place according to the invention in a simple mode of operation, without great technical effort and with a moderate input of energy. Since the enzymes and / or chemical compounds used to digest the biomass by aerobic microorganisms directly within the reactor in which the digestion takes place, i. In situ, are synthesized, and therefore the addition of digestion chemicals or the addition of digestion-promoting enzymes is obsolete, an energy-efficient digestion without pressure or steam or the addition of chemicals / enzymes is possible.

A multiplicity of vegetable and maritime raw materials can be used economically by the process according to the invention, in particular fractions in which energy recovery has hitherto not made sense.

Due to the microbial digestion an autonomous process is realized, whereby only the biomass has to be supplied from outside the process. Furthermore, the equipment used for biolysis digestion can be arranged very compactly in terms of apparatus and does not contain pressure-bearing components.

The combination with existing biogas plants is possible and enables the exploitation of a broader and more seasonal biomass spectrum (revamp, resource value mapping).

The process according to the invention is preferably developed in such a way that aerobic, wood degrading, cellulase-producing microorganisms, in particular Fusarium solani, Trichoderma viride or Talaromyces emersonii are used.

The aforementioned fungi use cellulosic biomass as a substrate and synthesize, inter alia, the enzyme cellulase, which decomposes cellulose into its basic building blocks. Through the use of wood-degrading, cellulase-producing microorganisms, the digestion of cellulosic biomass is induced and accelerated.

The process according to the invention is preferably developed in such a way that aerobic, nitrogen-fixing microorganisms, in particular microorganisms of the genus Azomonas or Azotobacter, are used.

Nitrogen-fixing bacteria reduce elemental molecular nitrogen (N2) to ammonium (NH4 +) or, depending on the prevailing vapor pressure, to ammonia (NH3). Ammonium / ammonia is microbiologically produced in situ by using nitrogen-fixing bacteria.

Ammonium or ammonia is essential for biomass digestion. Nitrogen-fixing bacteria accordingly provide a non-pressurized alternative without external chemical handling as compared to the prior art AFEX digestion process, in which lignocellulose is leached in liquid ammonia at high pressure and then the pressure is released explosively.

Nitrogen is also essential for microbiological growth. As is known, pure vegetable raw materials have a very low nitrogen content. For microbiological growth, e.g. in the biogas fermenter, however, a nitrogen content of about 11% is necessary.

With the help of nitrogen-fixing microorganisms, this deficiency can be remedied. Furthermore, the ammonium formed by the nitrogen-fixing microorganisms has the advantage that it stabilizes the pH, in particular in the digestion bioreactor.

Advantageously, the method according to the invention is further developed in that the biomass is subjected to a thermal pretreatment before the microbiological digestion.

Due to the / the steam / condensate resulting from the thermal pretreatment under the effect of temperature, the biomass degradation is accelerated. The organic substances released during the pretreatment (including tannic acids), the elevated temperature and the flue gas ("smoking") have a germicidal effect, which results in inertisation (sanitization, pasteurization, sanitation in a broader sense)

Process step to deplete potentially disturbing microorganisms in the biomass, not necessary.

The method according to the invention can be developed, in particular, such that the digestion of the biomass by the aerobic, wood degrading, cellulase-producing microorganisms is carried out in a digestion bioreactor and the digestion of the biomass by the aerobic, nitrogen-fixing microorganisms is carried out in a bioreactor downstream of the digestion bioreactor.

The cellulosic biomass is subjected here to an enzymatic and a chemical digestion, wherein the biomass is decomposed steadily. Furthermore, the microorganisms present in the downstream bioreactor benefit from the metabolic products synthesized in the digestion bioreactor

Digestive bioreactor microorganisms located there, as nitrogen-fixing bacteria, among other things, use carbohydrates as an energy and fuel source and they are created by the digestion of biomass in digestion bioreactor. As already mentioned, the cellulose of the cellulosic raw materials of cellulase-producing, wood-degrading microorganisms is split into glucose, cellobiose and cello-oligosaccharides, which in turn can be used as an energy source for the bacteria in the bioreactor and especially for the microorganisms in a bioreactor downstream biogas digester ,

Preferably, the digestion bioreactor a

Include trickling column.

As an alternative to the bioreactor, the digestion of the biomass by the aerobic, nitrogen-fixing microorganisms can preferably also be carried out in a trickling column column connected downstream of the digestion bioreactor.

The digestion bioreactor is preferably designed as a shaft reactor, which is filled in the lowest area directly on the support grid, with packing, i. the lower part of the digestion bioreactor is designed as a packed bed. The fractionated raw material, for example shrub chips, is conveyed into the upper part of the shaft and forms a continuous downward moving bed. Digestion bioreactor and bioreactor can each be designed as separate apparatus. Preferably, however, these are combined in a single apparatus.

Advantageously, the method according to the invention can be further developed such that at least part of the microbiologically digested biomass and / or part of the microorganisms from the digestion bioreactor and / or some of the microorganisms from the bioreactor are fed to a biogas fermenter.

In a biogas fermenter, biomass is converted into biogas (mixture of CH4 and COz) in a multi-stage process (hydrolysis, acidogenesis, actetogenesis, methanogenesis) by microorganisms in the biogas fermenter.

The microbiological digestion before fermentation allows the conversion of biogenic raw materials into biogas, whereby the microbiologically digested biomass requires a shorter residence time of the substrate in the biogas fermenter, since the biomass can be utilized more easily by the microorganisms present in the fermenter.

In addition to the actual digestion of the biomass used, the microorganisms used also have the function and the great advantage that their intracellular storage materials are valuable substrate components for the biogas fermenter.

In particular, it may be provided that excess biomass is withdrawn from the biogas fermenter and subjected to filtration, and the filtrate is fed to the digestion bioreactor.

The separation of the excess biomass by means of solid-liquid separation with (partial) filtrate recirculation is advantageous in that the Fementationsbrühe remains in the process and the process water requirement decreases or decreases the disposal of the digestate. This is particularly advantageous in municipal installations and wherever there are no sufficient agricultural areas available for spreading the fermentation residues.

The inventive method is advantageously developed such that nutrients are recirculated from the bioreactor in liquid, dissolved and suspended form in the digestion bioreactor, wherein at least some of the nutrients from the digestion bioreactor tapers.

The resulting ammonium, which is fixed in the bioreactor from atmospheric nitrogen, has a stabilizing effect on the pH in the digestion bioreactor.

As mentioned earlier, the microorganisms present in the bioreactor benefit from the

Digestive bioreactor synthesized metabolic products of the microorganisms living there.

The process according to the invention is developed in an advantageous manner to the effect that the temperature in the thermal pretreatment between 60 ° C and 100 ° C, in particular maintained at 80 ° C.

The highly mobile condensing vapor phase prevailing in the pretreatment results in high penetration rates of the biomass. Fluctuating temperatures are quite advantageous, as the induced phase change of steam / condensate (solid / liquid) additionally accelerates biomass degradation.

The method may preferably be further developed such that the temperature in the digestion bioreactor is maintained at about 20 ° C to 40 ° C. In particular, it may be provided that the temperature in the bioreactor is maintained at about 30 ° C.

The aerobic, wood-degrading, cellulase-producing microorganisms colonizing the digestion bioreactor have an optimum at about 20 ° C. to 40 ° C.

Growth behavior. Talaromyces emersonii, for example, at about 40 ° C an optimal growth behavior, with Fusarium solani optimally at about 25 ° C and Trichoderma viride at about 24 ° C.

On the directly above the support bar arranged

Fill / packing (trickling filter / packing), the microorganisms form a biological lawn, which the suspended biomass from the overlying

Biomass bed further decomposed. This reduces the slippage of undecomposed cellulosic biomass into the bioreactor or the subsequent fermenter and increases the Raura time yield.

The optimum temperature for the nitrogen fixers in the bioreactor is around 30 ° C.

The decomposition bioreactor is also dominated by highly mobile condensing vapor phases, causing the

Penetration rate of biomass is extremely effective. By condensing vapors and sprinkling with suspension is further ensured that a perennial removal of microbiological and chemical

Reaction products takes place and an accelerated conversion is favored.

The digestion bioreactor and the bioreactor can be combined by apparatus, wherein the temperatures in the upper digestion bioreactor part e.g. for Talaromyces emersonii be maintained at about 40 ° C and in the lower bioreactor section to about 30 ° C.

The process according to the invention is preferably further developed such that biogas produced in the biogas fermenter is fed to a combustion unit, in particular to a burner of a combined heat and power plant.

Advantageously, the method according to the invention is further developed such that exhaust air from the combustion unit flows through the thermal pretreatment.

Particularly preferably, it can be provided that the exhaust air from the digestion bioreactor is supplied to the burner device, in particular for thermal pretreatment.

The exhaust air serves as supply air for the burner.

Furthermore, such a process management is the depletion of possible odor and air pollutants.

By the aforementioned steps, a self-sufficient process is realized, which can give off heat or electricity in the sense of regenerative energy production, wherein the heat required in the pretreatment and for the microorganisms is subtracted from other components associated with the process and introduced into the pretreatment.

The inventive method is advantageously developed such that exhaust air from the thermal pretreatment is subjected to condensation and the condensate is fed to the bioreactor, wherein preferably a partial stream is recycled to the thermal pretreatment.

The biomass bed of the pretreatment with its large surface in combination with the condenser also serves as a scrubber / filter for odors of the microbiological process steps. Additional equipment or facilities are therefore not necessary.

By returning the condensate further the necessary water requirement is minimized.

Preferably, the condenser is equipped with high surface area contact surfaces (packing, mist collectors), thereby simultaneously performing a scrubber function. Thus, odors that are contained in the exhaust gas to a small extent (depending on the type of biomass used), brought into the aqueous phase and recycled. This also applies to ammonia, which is also partially bound in the biomass bed with the carbon dioxide combustion.

The present ammonium forms ammonium salts (carbonates) with carbon dioxide from combustion and especially from methane formation.

The excess biomass of the biogas production is separated according to the state of the art and forms a biofertilizer enriched with nitrogen compounds. The thereby separated liquid can be partially recycled into the process.

Compared to vegetable composting of the biomass used, the surplus biomass from the biogas production contains a significant nitrogen content and thus has a higher fertilizer quality.

The method according to the invention can be developed, in particular, such that during the thermal pretreatment plant ingredients or essential oils are extracted from the biomass, which are discharged via the exhaust air and transferred into the condensate in the condenser and separated from the condensate.

In the pretreatment thermal and extractive and distillative processes take place. This releases phytonutrients (essential oils, e.g., terpenes) and, in the case of volatility, analogous to steam distillation and assisted by the flue gas flow, i. the exhaust air from the combustion unit, which flows through the thermal pre-treatment discharged and transferred into the condensate. These can be separated by separating the density with a decanter from the condensate, wherein the water is recycled to the process.

It is interesting in the presence of suitable biomass, the ability to win in addition to electricity, heat and biofertilizer as a by-product also essential oils and hydrolates or vice versa in the extraction of essential oils to generate electricity and heat. The co-production of essential oils and hydrolates, for example, from waste cinders of sawmills or waste fractions during felling (branches, needles) done. For example, (pine) pine oils, spruce oils, fir oils or mixtures can be produced. Also, the production of citrus oils, orange oils, sandalwood oils or seaweed oils are possible in this way. The oil mixtures can be used as flavorings or perfumes, for example in the cosmetics industry, medicine, the

Food industry, as insecticides or in color production (paints, oils).

In particular, it may be provided that the

Digestion bioreactor and the digestion bioreactor downstream bioreactor air is supplied from below.

Since it is both in the digestion bioreactor and in the bioreactor microorganisms are aerobic microorganisms, an air supply from below both components is advantageous, as this sufficient air is fed into both components, only one supply line is necessary.

The invention will be explained in more detail with reference to application examples.

Application example 1

Shrub cut, garden waste, bamboo, seaweed and inferior woodchips with a high proportion of green are filled discontinuously from above into a silo bunker in container format. This is equipped with a sliding floor and underlying slotted sheets.

Below the plates warm combustion exhaust gases are supplied, which flow through the biomass bed upwards. This will make the biomass in one

Temperature window maintained between 60 ° C and 95 ° C, on average around 80 ° C.

Above the bed, the exhaust air is drawn off to the side and passed through a condenser. The capacitor is used in Application Example 1 due to the moderate

Ambient temperature not active, but passively cooled.

The resulting condensate is returned to the process.

Following the sliding floor is a

Trough auger. The biomass is then fed into a following riser, which in turn doses into the digestion bioreactor. The screw conveyors are used as a cooling zone. The biomass is cooled down to the digestion bioreactor temperature of about 4Q ° C.

The digestion bioreactor is a thermally insulated stationary silo. On the first third of a Auflagerost is arranged with a packed bed. The biomass listed above forms an air-permeable layer on the bed. Below the packed bed of air is supplied, which leaves the silo above and is fed as supply air into the burner or at its stoppage (discontinuous burner guide) is guided below the slot floors in the silo bunker.

In the biomass layer and the underlying

Trickler column are aerobic at about 40'C

Microorganisms of the genus Talaromyces emersonii cultivated. They gradually decompose the biomass layer. The resulting degradation products, including excess biomass, are suspended and dissolved in the underlying bioreactor.

In the bioreactor aerobic microorganisms of the genus Azotobacter beijerinkcii are cultured at 30 ° C. The effluent suspension has a pH of 7 +/- 0.5. A partial stream is returned to the digestion bioreactor. The second partial stream is submerged as a substrate in the biogas reactor (fermenter) out. In addition, condensate of the condenser and optionally supernatant water from the solid-liquid separation of biogas production are introduced into the bioreactor.

The inoculum is carried out for Talaromyces emersonii via the recirculation line and for Azotobacter beijerinkcii via the condensate return.

The biogas fermenter is operated according to the state of the art and for the application example mesophilic in the temperature range of the microbiological digestion. In this, anaerobic methanogens are cultured according to the prior art (for example, yeasts, clostridia, zymomonas, methanogens).

Recirculation of filtrate from the removal of the excess biomass per se did not adversely affect the process. To date, however, no complete cycle closure has been performed for a long time, as it may also concentrate growth inhibitors.

The biogas is burned in the application example with atmospheric oxygen in a burner. The exhaust gas is fed to the silo bunker after the flue gas condensation. The hot flue gas condensate is pumped into the biomass bed of the silo bunker.

In the application example, the following results

Volume ratios and throughputs:

Digestive bioreactor approx. 8m3 packed bed approx. Im3 bioreactor approx. 3m3 biogas digester approx. 2m3 pretreatment 50m3

Use amount of biomass approx. 10 cubic meters per day

Discharge mud about 300kg (TS) per day

Power 350kW thermal (calorific value), 100kW electric

Furthermore, a co-production of essential oils can take place:

For this purpose, the condensation is carried out in two stages. In the main condenser, the exhaust gas of the pretreatment is cooled in countercurrent with the exhaust air of the digestion bioreactor. The secondary condenser is cooled on the secondary side with ambient air, which is used in the digestion bioreactor. The condensate from both stages is siphoned into a decanter. The heavy, aqueous phase is withdrawn below and returned to the process. The lighter organic phase is stripped off and used as a co-product. The temperature in the thermal pretreatment can also be at the boiling point of water.

In the co-production of essential oils, it has been found that the addition of caustic (caustic soda, caustic lye) in the pretreatment improves the yield by increasing the leaching / extraction rate and a pH of 8 +/- 1 in the pretreatment improves the overall process not negatively affected.

Example of application 2

Method and device for biogas production including auxiliary equipment, control and combined heat and power plant are integrated in a 20 foot iso-container. Safety equipment (torch) and the recooler are mounted on the outside of the container. Also outside the container is an optional gas storage.

Operating data:

Volume pre-treatment 2m3 digestion bioreactor approx. 300L bioreactor approx. 100L

Biogas fermenter about 70L

Use amount of biomass approx. 0.4 meters per day Discharge sludge approx. 12kg (TS) per day Power CHP: 15kW thermal, 4kW electric

The crushed biomass is drawn in discontinuously into a 2m3 silo bunker. At the bunker floor warm combustion gases are supplied, which flow through the biomass bed upwards. This keeps the biomass in a temperature range between 60 ° C and 95 ° C, on average around 80 ° C.

Above the bed, the exhaust air is drawn off and led into a condenser, which is preferably located on the container roof and is passively cooled by the ambient temperature. The resulting condensate is returned to the process.

The biomass is metered into the digestion bioreactor with a discharge screw. The screw conveyor is used as a cooling zone. The biomass is cooled down to the bioreactor temperature of about 40 ° C.

The digestion bioreactor is a thermally insulated container. The lower area is filled with a packed bed, which rests on the bottom of a grate. The biomass listed above forms an air-permeable layer on the bed.

Below the packed bed of air from the bioreactor is supplied, which leaves the container above and is fed as supply air into the burner or at its stoppage (discontinuous burner guide) is guided into the bottom region of the silo bunker.

In the biomass layer are at about 40 ° C aerobic

Microorganisms of the genus Talaromyces emersonii cultivated. They gradually decompose the biomass layer. The resulting decomposition products, including excess biomass, are suspended and dissolved in the bioreactor via the packed bed.

In addition, condensate of the condenser and optionally supernatant water from the solid-liquid separation of biogas production are introduced into the bioreactor. In the bioreactor aerobic microorganisms of the genus Azotobacter beijerinkcii are cultured at 30 ° C. Air is supplied to the bioreactor via a distributor tube in the lower region, which passes through the liquid and is conducted from the vapor space into the digestion bioreactor.

The effluent suspension has a pH of 7 +/- 0.5. A partial flow is recycled to the biomass layer. The second partial stream is submerged as a substrate in the biogas reactor (fermenter) out.

The production of biogas produces state-of-the-art biogas, which is energetically utilized in a combined heat and power plant. The latter keeps the digestion bioreactor, the bioreactor and the fermenter at operating temperature with a heat transfer circuit. The flue gas is fed into the silo bunker.

Application example 3

The device for digestion process for the production of biogas is designed in accordance with the biogas plant technology as a fixed installation in reinforced concrete.

Operating data:

Volume pretreatment 1000m3

Digestion reactor 150m3, diameter 5m, height 10m bioreactor 60ms, diameter 5m, height 3m biogas digester 40m3

Use rate of biomass approx. 200 meters per day Power 6.5MW thermal, 2MW electrical

The comminuted biomass is discontinuously charged by means of a charging device into a rectangular silo bunker made of cast-in-situ concrete - similar to the bunker technology for wood chips. At the bunker floor warm combustion exhaust gases are fed through slotted plates, which flow through the biomass bed upwards. This keeps the biomass in a temperature range between 60 ° C and 95 ° C, on average around 80 ° C.

Above the bed, the exhaust air is drawn off and led into a condenser, which is preferably passively cooled by the ambient temperature. The resulting condensate is returned to the process. The biomass is dosed into the digestion bioreactor with a grate bottom and a discharge screw. The screw conveyor is used as a cooling zone. The biomass is cooled down to the digestion bioreactor temperature of about 40 ° C.

The digestion bioreactor is a thermally insulated reinforced concrete silo with a round cross section. The biomass bed is located in the first third of a grid on which random packing and forms an air-permeable layer, which is traversed from below with air from the bioreactor. The air is circulated in the silo in recirculation mode via packed bed and biomass bed and thermostated at 40 ° C.

In the biomass layer become aerobic at 40 ° C

Microorganisms of the genus Talaromyces emersonii cultivated. They gradually decompose the biomass layer. The resulting decomposition products, including excess biomass, are suspended and dissolved via the packed bed into the bottom sump of the silo.

The suspension from the digestion bioreactor passes through the support shelf into the bioreactor. From below, air is injected via a distribution ring at 30 ° C thermostatically controlled air.

In the bioreactor aerobic microorganisms of the genus Azotobacter beijerinkcii are cultured at 30 ° C. The resulting degradation products are suspended including excess biomass and dissolved in the

Digestion bioreactor recirculated; A partial stream is fed as substrate into the biogas reactor (fermenter). The effluent suspension has a pH of 7 +/- 0.5. In addition, condensate of the condenser and optionally supernatant water from the solid-liquid separation of biogas production are introduced into the bioreactor.

The production of biogas produces state-of-the-art biogas, which is energetically utilized in a combined heat and power plant. The latter holds with a heat transfer circuit, the fermenter and the

Silo constructions at operating temperature. The flue gas is fed into the silo bunker.

The inventive method will be explained in more detail with reference to embodiments schematically illustrated in the drawings. 1 shows a method sequence according to a first embodiment of the present invention, and FIG. 2 shows a method sequence according to a second embodiment of the present invention.

In Fig. 1, the thermal pretreatment is designated 1. 1 shows a digestion bioreactor 2, and a bioreactor 3 connected downstream of the digestion bioreactor 2, a fermenter 4 connected downstream of the bioreactor, and a burner device 5, wherein the combustion device may alternatively also be an internal combustion engine.

Via biomass input 6, the biomass to be digested is introduced into the thermal pretreatment 1 and subsequently metered into the digestion bioreactor 2. The digestion bioreactor 2 is preferably designed as a shaft reactor. The bioreactor 3 is designed as a gassed stirred tank, with good gas distribution by means of distribution pipes, a stirrer is not essential. The biomass to be digested, for example

Shrub chips, will be from the thermal

Pretreatment 1 in the upper part of the

Stimulating bioreactor 2 promoted and forms a steadily migrating down bed.

The biomass is steadily decomposed in the thermal pretreatment 1, the digestion bioreactor 2 and the bioreactor 3 under the influence of temperature and by the chemical-physical action of vapors or condensate, as well as the enzymatic and degradative action of microorganisms present in the digestion bioreactor 2 and the bioreactor 3.

In the pretreatment 1, the biomass is thermally treated, wherein exhaust air is introduced from the burner device 5 via the line 7 in the thermal pretreatment 1 and flows through them. Thus, the temperature is heated in the thermal pretreatment to temperatures between 60 ° C and 100 ° C and maintained at this temperature level.

In the digestion bioreactor 2 and in the bioreactor 3 aerobic microorganisms are located to microbiologically digest the biomass. The necessary air for aerobic microbiology is supplied in the bioreactor 3 via the line 8 from below, flows through the bioreactor 3 from bottom to top and reached via the line 9 the digestion bioreactor 2, which is also traversed from bottom to top with air. If necessary, the air can be preheated with (waste) heat from the burner device 5 to the optimum growth temperature of the microorganisms.

The exhaust air from the digestion bioreactor 2 is supplied as supply air to the burner device (not shown in Fig.l) or passed via the line 10 in the pretreatment 1, which is also a biofilter for vapors / gases from the bioreactors. The moist exhaust gases from the pretreatment 1 are withdrawn via line 11 from the process.

From the bioreactor 3, nutrients in liquid, dissolved and suspended form are continuously recirculated into the digestion bioreactor 2 (circulation designated 17). From the bioreactor 3, a portion of the digested biomass and the microorganisms is passed via the line 12 in the biogas fermenter 4, where they serve as a substrate for the fermentation taking place there. Supernatant liquid from biogas fermenter 4 can be optionally and partially recycled via line 13 to bioreactor 3 and excess biomass is withdrawn via line 14. Via the line 15, biogas passes from the fermenter 4 into the burner device 5, which is supplied with air via the line 16.

Fig. 2 also shows a thermal pretreatment 1, 'a digestion bioreactor 2, a bioreactor 3, a

Fermenter 4 and a burner device 5, wherein the

Digestion bioreactot 2 and the bioreactor 3 in this

Embodiment are integrally formed.

Identical parts are given the same reference numerals as in FIG

Fig.l provided.

The exhaust air from the digestion bioreactor 2 is over the

Conduit 10 is passed into the pretreatment 1 (or optionally first passed through the burner device), which is also a biofilter for vapors / gases from the bioreactors. The moist exhaust air from the pretreatment 1 is - in contrast to the one shown in Fig. 1

Embodiment - passed through the line 11 'in a condenser 21, there condensed out and returned via the line 18 in the process. The exhaust air from the condenser 21 is withdrawn via the line 19.

Preferably, the condenser 21 is provided with high surface area contact surfaces (packing, mist collectors), thereby also performing a scrubber function.

In pretreatment 1, both thermal and extractive and distillative processes take place. As a result, plant ingredients are released and in the case of volatility analogous to the water or

Carrier vapor distillation with additional gas stream 7 from the firing unit 5 in the liquid phase and subsequently transferred to the vapor phase. The vapors 11 'are condensed out in the condenser 21. These can then be separated from the condensate by density separation with a decanter, which is preferably integrated in the condenser 21.

Claims (17)

claims: 1. Process for the utilization of cellulosic biomass, such as e.g. Wood chips, shredded shrubs, kelp or bamboo, comprising the digestion of the cellulosic biomass, characterized in that enzymes used for the digestion of the biomass and / or chemical compounds are prepared by aerobic microorganisms in situ microbiologically. 2- Method according to claims 1, characterized in that aerobic, wood degrading, cellulase producing microorganisms, in particular Fusarium solani, Trichoderma viride or Talaromyces emersonii be used. 3. The method according to claim 1 or 2, characterized in that aerobic, nitrogen-fixing microorganisms, in particular microorganisms of the genus Azomonas or Azotobacter be used. 4. The method according to claim 1, 2 or 3, characterized in that the biomass is subjected before the microbiological digestion of a thermal pretreatment. 5. The method according to claim 2, 3 or 4, characterized in that the digestion of the biomass by the aerobic, wood degrading, cellulase-producing microorganisms is carried out in a digestion bioreactor and the digestion of biomass by the aerobic, nitrogen-fixing microorganisms in a digestion bioreactor downstream bioreactor is made. 6. The method according to any one of claims 1 to 5, characterized in that at least a portion of the microbiologically digested biomass and / or a portion of the microorganisms from the digestion bioreactor and / or a portion of the microorganisms from the bioreactor is fed to a biogas fermenter. 7. The method according to any one of claims 1 to 6, characterized in that excess biomass is withdrawn from the biogas fermenter and subjected to a filtration and the filtrate is fed to the digestion bioreactor. 8. The method according to any one of claims 1 to 7, characterized in that nutrients are recirculated from the bioreactor in liquid, dissolved and suspended form in the digestion bioreactor, wherein at least a portion of the nutrients from the digestion bioreactor tapers. 9. The method according to any one of claims 4 to 8, characterized in that the temperature is maintained in the thermal pretreatment between 60 ° C and 100'C, in particular to 80 ° C. 10. The method according to any one of claims 5 to 9, characterized in that the temperature in the digestion bioreactor to about 20 ° C to 40 ° C, is maintained. 11. The method according to any one of claims 5 to 10, characterized in that the temperature in the bioreactor is maintained at about 30 ° C. 12. The method according to any one of claims β to 11, characterized in that biogas produced in Biogasfermenter a firing unit, in particular a burner of a combined heat and power plant is supplied. 13. The method according to claim 11, characterized in that exhaust air from the combustion unit flows through the thermal pretreatment. 14. The method according to any one of claims 5 to 13, characterized in that the exhaust air from the digestion bioreactor; is fed in particular for the thermal pretreatment of the burner device. 15. The method according to any one of claims 4 to 14, characterized in that exhaust air from the thermal pretreatment is subjected to a condensation and the condensate is fed to the bioreactor, wherein preferably a partial stream is recycled to the thermal pretreatment. 16. The method according to claim 15, characterized in that extracted during the thermal pretreatment plant ingredients or essential oils from the biomass, which are discharged via the exhaust air and transferred in the condenser in the condensate and separated from the condensate. 17. The method according to any one of claims 5 to 16, characterized in that the digestion bioreactor and the digestion bioreactor downstream bioreactor air is supplied from below.