DE102011120888B3 - Degradation of biogenic material, comprises carrying out thermo-mechanical pulping and recycling food ingredients and other organic waste including fermentation residues in multistage system by homogenizing in mixing- and grinding system - Google Patents

Abstract

Degradation of biogenic material, comprises: carrying out the thermo-mechanical pulping and recycling the ingredients of food residues and other organic waste including the fermentation residues in a multistage system. The raw material to be recovered are homogenized in a rotating mixing- and grinding system (1), diluted with water from the circulating system and a continuously operating thermo-compression hydrolysis system (2) at 130-150[deg] C. The biogas produced in the anaerobic operating step floats in a floating bed reactor and has a methane content of >= 80%. Degradation of biogenic material, comprises: carrying out the thermo-mechanical pulping and recycling the ingredients of food residues and other organic waste including the fermentation residues in a multistage system. The raw material to be recovered are homogenized in a rotating mixing- and grinding system (1), diluted with water from the circulating system and a continuously operating thermo-compression hydrolysis system (2) at 130-150[deg] C. The biogas produced in the anaerobic operating step floats in a floating bed reactor and has a methane content of >= 80%. The remaining organic substance degraded in the aerobic operating stages equipped with a membrane ventilation system in the downstream. The hydrogen-consuming methane production compared to the acetate-consuming methane formation amplifies an increase in the hydrogen concentration in the substrate by hydrogen-forming microorganisms. The sewage sludge is used as an initiator and mediator for enhanced hydrogen-consuming methane formation. The remaining coarse solids are separated, dried and pelletized by separation according to thermo-compression hydrolysis and the pre-hydrolysis. The separation of the resulting centrifugate is carried out using water, to a dry matter content of 3-5% and a methane content of maximum of 2500 mg/l, and a working temperature is adjusted to 30-55[deg] C, where acid forming microorganism cultures are inoculated in a hydrolysis tank such that the acids required for the production of biogas are formed in anaerobic conditions, and a pH is adjusted to 6.5-7. The promotion of the pre-hydrolyzed substrate is carried out in the floating bed reactor for anaerobic biogas production at a temperature of 35-50[deg] C in the up flow principle. The carbon-containing cleavage products and microorganisms, which are discharged from the reactor, are concentrated by the external insertion of a micro- or ultra-filtration stage in the end of the anaerobic reactor or many reactors connected in parallel or in series, such that long chain cleavage products, and microorganisms are returned to the biogas process. The separated filtrate is further purified on a floating bed column (8) under aerobic conditions and then subjected to a thermization at 60-75[deg] C for killing the microflora and is processed in an ultrafiltration system and a downstream, two-stage reverse osmosis system. The residual gas e.g. methane, carbon dioxide, hydrogen sulfide, which are remaining in the liquid are removed via an upstream vacuum separator from the liquid at a reduced pressure of -0.2 to -0.4 bar before ultrafiltration. An independent claim is also included for plant containing a floating bed reactor column with anaerobic and aerobic steps and integrated membrane operating stages for recycling of organic residues in the degradation step and recycling of the treated water in the treatment process, comprising at least a separation device for non-organic impurities as a coarse separation, a rotating mixing- and grinding system with homogenizing, a thermo-compression hydrolysis system, a separation plant, such as screw pressing screws, decanter or vibrating sieve, a drying and pelletizing plant (5), an enzymatic pre-hydrolysis by incubation with microorganisms at 55[deg] C, an up flow anaerobic floating bed reactor (6), an aerobic operating step, which is designed as floating bed reactor and which is equipped with floating bodies with a density of 0.95-0.98 g/cm 3>and a diameter of 50-250 mm, a microfiltration, an intensive ventilation for air entry into the aerobic up flow floating bed, a thermization system for thermal treatment of the effluent from the aerobic floating bed reactor, a degassing system with carbon dioxide removal to improve the ultrafiltration performance, an ultrafiltration system, a return of the resulting concentrate into the anaerobic floating bed reactor, a transmission of the filtrate to a reverse osmosis, a reverse osmosis system to concentrate the mineral content and recycling of the reverse osmosis water to thermocompression hydrolysis and production of pure water, and a membrane-intensive entry and ventilation system.

Description

The invention relates to a method for biogas production by digestion and utilization of the ingredients from food residues and other organic waste including the digestate treatment and an apparatus for performing the method.

Various methods are known for the use of manure, renewable raw materials and organically heavily polluted wastewater for the production of biogas, fertilizers and water from digestate.

From the DE 10 2005 055 310 A1 is a process for the processing of digestate from biogas plants, liquid manure, organically polluted wastewater, inter alia, by linking several process chains to complex circulatory systems known.

The patent 10 2005 055 310 A1 the object is to provide a method that all Bestanteile and energy content in the complex context of use of the included thermal and electrical energy, the recycling / degradation of the ingredients and water use for high-quality purposes, eg. B. aqua cultures.

The solution given in this document consists of a system of circulation for the treatment and utilization of fermentation residues from biogas plants for the use of excess water and energy for the rearing of fish cultures while maximizing the total energy yield by anaerobic filter and the targeted further degradation of C and N substances Aerobic filter with simultaneous use of the resulting CO ₂ and residual nitrogen of the reverse osmosis concentrates for algae cultures.

In the DE 10 2004 053 615 B3 the use of a solid-mist reactor with percolation is described, wherein several perculators are arranged in a fixed-bed reactor.

This is to be the degradation of biogenic material under need-based control of the biogas attack.

That in the WO 2010 034 685 A2 described method and apparatus for the treatment of biogenic substances is primarily a method for increasing the biogas yield by the entry of mechanical energy with the aim of increasing the efficiency of biogas production from biogenic raw materials, but not the complete utilization of the ingredients to fertilizer concentrates and the water to process water ,

The reactors, starting materials and process principles used in these documents and other methods known from the art do not achieve the desired technical and economic success.

The EP 1 211 308 A1 relates to a process for the partial utilization of meat-and-bone meal and / or its precursors.

The invention is based on the object to provide an inexpensive method for the utilization of animal meal, in which the amount of a substance to be supplied combustion is reduced.

There is no processing of a liquid obtained in a separation provided directly after anaerobic fermentation by filtration. Special membrane filtration processes are known to be technically and energetically very complicated and problematic according to the prior art.

A complex use of ingredients and the recycling of the ingredients is not provided.

The invention has for its object to provide a method that a complex use of the ingredients of food residues, plant, slaughter and fish waste and other organic waste with regard to the recycling or degradation of the ingredients for energy use (thermal and electrical energy) and the use of the resulting purified water in the material cycle allows.

Furthermore, to be shown with the invention, the device provided for execution.

The object is achieved by a process for the digestion and utilization of the ingredients of food residues and other waste products whose characteristics are given in the main claim.

The device is shown in claims 2-10.

The solution according to the invention consists of a complex system for the thermomechanical digestion of organic raw materials, a Schwimmbettreaktorenkolonne with anaerobic and aerobic stages and integrated membrane separation stages for recycling organic residues in the mining stages and recycling the purified water in the treatment process and for other uses.

The process aims at raw materials whose recycling in biogas reactors requires long residence times and thus requires large reactor volumes.

In the anaerobic working stage, which is designed as a floating bed reactor, biogas is produced with a methane content of ≥ 80%; In the downstream, equipped with a special membrane intensive aeration system aerobic work stages, the degradation of remaining organic matter and an oxidative conversion of ammonia compounds to nitrate compounds takes place. As a result, an almost complete nitrogen removal in the reverse osmosis is possible.

The anaerobic as well as the aerobic working stages are designed as floating bed reactors and have floats with a density of 0.95-0.98 g / cm ³ and a diameter of 50-250 mm. The bed design according to the invention ensures that no blocking of the bed is possible, and effective settling of the biosludge can take place below the floating bed.

According to the invention, the methane formation process is designed such that the hydrogen-consuming methane formation is enhanced compared to the acetate-consuming methane formation. The hydrogen-consuming methane formation is energetically more favorable than the acetate carboxylation. This is achieved by increasing the hydrogen concentration in the substrate by H-forming microorganisms such. B. spore-forming clostridia. Sewage sludge serves as a starter and mediator for increased hydrogen-consuming methane formation.

The raw materials to be recycled, such as food residues, vegetable, slaughter and fish waste, are largely homogenized in a rotating mixing and grinding system and diluted with water from the circulatory system and largely at 130-150 ° C via a continuous thermo-pressure hydrolysis plant open minded.

Remaining coarse solids are separated by means of separation (screw extruder / decanter / vibrating screen) and further adjusted with water to a dry matter content of 3-5% and an H-forming <2000 mg / l. This suspension is cooled to a working temperature between 30-55 ° C and inoculated in a hydrolysis tank with acid-forming microorganism cultures and under quasi-anaerobic conditions, the formation of the organic acids required for biogas production takes place. To optimize the methane formation, a pH correction can be carried out here, preferably to pH 6.5-7.0.

The pre-hydrolyzed substrate is pumped upflow through the anaerobic pool bed reactor. Here, the biogas formation takes place, which can be designed both meso- and thermophilic. (Temperature range 35-55 ° C)

• – Die Mikrofiltrationsanlage besteht aus polymeren oder keramischen Rohrmembranen mit einem Rohrdurchmesser von 3–25 mm und mit einer Porenweite von 0,05–0,4 μm
• – Strömungsgeschwindigkeit in den Rohren: 3–6 m/s
• – Transmembrane Druckdifferenz:
• – Polymermembranen: max. 1,0 bar
• – Keramikmembranen: max. 2,0 bar
• – bei Porenweiten 0,2–0,4 um:
• – Filtratdruck gegen 0,4–0,8 bar
• – Rückspülmodus mit Recycling-Wasser
• – 0,5–1,0 bar über Transmembrandruck
• – bei Leistungsverlust > 50% auch Möglichkeit der Umkehrspülung bei gleichzeitiger Rückspülung

In the course of the anaerobic reactor, a micro / ultrafiltration stage is connected externally, which concentrated so far discharged from the reactor, still containing C-containing fission products and loaded with microorganisms drain that long-chain fission products and microorganisms can be recycled into the biogas process.

• - The microfiltration system consists of polymeric or ceramic tube membranes with a tube diameter of 3-25 mm and with a pore size of 0.05-0.4 microns
• - Flow rate in the pipes: 3-6 m / s
• - Transmembrane pressure difference:
• - Polymer membranes: max. 1.0 bar
• - Ceramic membranes: max. 2.0 bar
• At pore sizes 0.2-0.4 μm:
• - Filtratdruck against 0.4-0.8 bar
• - Backwash mode with recycled water
• 0.5-1.0 bar via transmembrane pressure
• - With loss of power> 50% also possibility of reverse flushing with simultaneous backwashing

The separated filtrate, on the other hand, depending on the nature and size of the residual load, is either passed directly through a one- or two-stage reverse osmosis plant where it is processed to a mineral concentrate and water or further purified under aerobic conditions by a floating bed column and then worked up in a on or off subjected to two-stage reverse osmosis system.

In the 1st stage of the reverse osmosis system winding membrane elements with a spacer of 30-120, preferably 40-100 mils (about 1.0-2.5 mm) and in the 2nd stage of the reverse osmosis system are wound membrane elements with a spacer of 30- 80, preferably 30-50 mil (about 0.8-1.2 mm) used.

Before the discharge from the anaerobic or aerobic swimming pool reactors into the water treatment, consisting of ultrafiltration and 1-2-stage reverse osmosis system, it is necessary to remove the residual gas in the liquid (CH ₄ , CO ₂ , H ₂ S), since gases significantly affect the performance of the system and can lead to extreme performance degradation.

This is especially true when the pH of the effluent for the effective separation of remaining NH ₄ components must be reduced to pH values <6.0. The addition of acids to the pH reduction leads to the formation of CO ₂ and H ₂ S.

These gases are deposited according to the invention via an upstream vacuum separator from the liquid at a reduced pressure of preferably -0.2 to -0.4 bar. In the separator, the liquid is directed via a tangential distributor on baffles. The baffles are arranged so that the liquid is then passed over the baffles in a thin film, the gases are separated and the liquid phase can be largely removed free of gases from a collector.

The entry of the filtrate in the aerobic floating bed reactor, z. B. from the microfiltration plant via a Membranintensiveintrags- and ventilation system. The air is pressed under pressure into the filtrate for better solubility of the oxygen through membranes in the finest distribution and relaxed in the reactor.

• – ein neuartiges Eintragungssystem für Luft in Klärsysteme mittels keramischer oder polymerer Cross-Flow-Module zur Erhöhung der gelösten Sauerstoffanteile im Medium
• – durch die zwangsgeführte, konstant komprimierte Luftzufuhr wird eine intensive und maximale Sauerstoffversorgung der Mikroflora in z. B. Schwimmbettreaktoren gewährleistet
• – bedingt durch den konstanten Überdruck im Cross-Flow-System von 0,5–4,0 bar wird die Löslichkeit des eingetragenen Luftsauerstoffs deutlich erhöht (25–40%) der bei Normaldruck eine nur geringe Löslichkeit in Wasser aufweist (20°C: 1 RT Wasser löst 0,039 RT O₂)
• – Das mit Sauerstoff anzureichernde Abwasser überströmt die Membranen mit Geschwindigkeiten von 3–5 m/s
• – Die Entspannung des Luft-Abwasser-Gemisches auf 0–0,3 bar Überdruck erfolgt über Tangential-Prallteller in den unteren Bereich des aerob betriebenen Schwimmbettreaktors (Aufstromprinzip).
• – Das Intensivbelüftungssystem wird vorzugsweise mit Membranen mit einer Porenweite von 0,05–0,1 μm betrieben und der hydraulische Durchmesser der Einzelkanäle der Membran liegt zwischen 6 und 8 mm.
• – Der mikrobielle Abbauprozess im Aerobreaktor wird somit um 25–30% beschleunigt.

The membrane intensive entry and ventilation system is characterized by:

• - A novel entry system for air in sewage treatment systems using ceramic or polymeric cross-flow modules to increase the dissolved oxygen content in the medium
• - Due to the positively driven, constantly compressed air supply is an intensive and maximum oxygen supply to the microflora in z. B. swimming pool reactors guaranteed
• - Due to the constant overpressure in the cross-flow system of 0.5-4.0 bar, the solubility of the atmospheric oxygen is significantly increased (25-40%) which at atmospheric pressure has only a low solubility in water (20 ° C: 1 RT of water dissolves 0.039 RT O ₂ )
• - Waste water to be oxygenated flows over the membranes at speeds of 3-5 m / s
• - The relaxation of the air-wastewater mixture to 0-0.3 bar overpressure via tangential baffle plate in the lower part of the aerobically operated swimming bed reactor (upflow principle).
• - The intensive ventilation system is preferably operated with membranes with a pore size of 0.05-0.1 microns and the hydraulic diameter of the individual channels of the membrane is between 6 and 8 mm.
• - The microbial degradation process in the aerobreactor is thus accelerated by 25-30%.

The water recovered from the reverse osmosis is directly recycled in the processing process for the exact adjustment of the N content in the substrate to max. 3000 mg / l, optimally 2000 mg / l ammonium. The supply of water can be done both in the prehydrolysis tank and in the inlet of the anaerobic fixed bed reactor.

The invention is a multi-stage system for the complete digestion and degradation of the contents of food residues and other organic wastes.

1 shows the procedure

The invention will be explained in a preferred embodiment.

embodiment

The food residues are transferred to a collection warehouse. From the collection warehouse, the food residues are passed through a drum screen via sludge pumps 0 given and freed of non-organic impurities. Subsequently, the fine crushing and homogenization takes place 1 via a rota-cut system.

The homogenized product is treated continuously in a heat exchanger or in a tube heat exchanger at 3.5 bar and 130 ° and then kept hot in a stainless steel pressure vessel for 30 minutes and then cooled to 55 ° C. By means of a metering system, the addition of microorganisms takes place in the form of seed sludge (sewage sludge) as well as of enzymes, such as cellulases.

It is then transferred to a prehydrolysis tank 3 with a residence time of 2 days.

The pre-hydrolyzed substrate is passed through a press screw separator 4 pumped with a mesh width of 0.5 mm and separated remaining fiber and other solids.

These solids are then dried and pelleted by means of a continuous belt dryer at 90-130 ° C and in a pelletizer / extruder 5 and optionally worked up with other fractions or additives.

The organically highly loaded liquid (centrate) is transferred from an intermediate storage to the anaerobic pool-bed reactor 6 promoted.

There, the biogas formation and the degradation of organic building blocks takes place at temperatures of 55 ° C (thermophilic process) and a residence time of the substrate of 4 days. The filling and the drainage of the residual liquid take place continuously.

By-pass is a microfiltration system (MF) 7 connected. The process from the anaerobic reactor 6 is via the MF system 7 (with polymer membranes with a tube diameter of 3-25 mm and a pore size of 0.2 microns) pumped; In the process, microorganisms and other components are concentrated and transferred to the swimming pool reactor 6 recycled. The filtrate is placed in the aerobic floating bed reactor 8th directed.

The introduction into the aerobic floating bed reactor 8th takes place via an intensive ventilation system 8.1 by injecting air into the liquid via a membrane system (0.2 μm ceramic membrane) under a pressure of max. 3.0 bar. This results in a finest distribution of air and a high solubility of the oxygen in the liquid is ensured.

The residence time in the aerobic floating bed reactor 8th is set with 4 days. Subsequently, a thermization takes place 9 the effluent from the reactor 6 at 75 ° C and a residence time of 2 minutes in a plate heat exchanger with a Rohrheißhalter and the degassing 10 at a low negative pressure of -0.2 bar.

After cooling to 60 ° C, the flow through an ultrafiltration plant 11 filtered at 60 ° C and 3 bar.

The resulting concentrate (about 10% dry substance) is in the aerobic reactor 8th the filtrate is cooled to 35 ° C in a plate heat exchanger and in a 2-stage reverse osmosis system 12 . 13 separated into a mineral concentrate and pure water.

The working conditions are 60 bar and 35 ° C.

In the 1st stage of the reverse osmosis system winding membrane elements with a spacer of 30-120, preferably 40-100 mils (about 1.0-2.5 mm) and in the 2nd stage of the reverse osmosis system are wound membrane elements with a spacer of 30- 80, preferably 30-50 mil (about 0.8-1.2 mm) used.

The mineral concentrate is derived at a concentration of 4-6%. The resulting pure water is used in the production cycle to adjust the dry matter content of the starting substrate.

LIST OF REFERENCE NUMBERS

0

coarse separation

1

Fine grinding / homogenization

2

Thermal pressure hydrolysis

3

prehydrolysis

4

separation

5

Drying / pelleting

6

Anaerobic upflow swimming pool reactor

7

microfiltration

8th

Anaerobic upflow swimming pool reactor

8.1

intensive ventilation

9

thermisation

10

degassing

11

ultrafiltration

12

Reverse osmosis 1

13

Reverse osmosis 2

Claims (10)

Process for the degradation of biogenic material, wherein the thermo-mechanical digestion and the utilization of the ingredients of food residues and other organic waste, including the processing of digestate in a multi-stage system, characterized in that - the raw materials to be recycled in a rotating mixing and crushing system ( 1 ) largely homogenized, diluted with water from the circulatory system and a continuous thermo-pressure hydrolysis plant ( 2 ) be digested at 130-150 ° C - in the anaerobic stage in a floating bed reactor ( 6 ) with floating bodies biogas with a methane content of ≥ 80% is produced - which in the downstream aerobic working stages equipped with a special membrane aeration system ( 8th ) degrades the remaining organic matter and an oxidative conversion of ammonia compounds to nitrate compounds - the hydrogen-consuming methane formation compared to the acetate-consuming methane an increase in hydrogen concentration in the substrate by H-forming microorganisms, is strengthened - as a starter and mediator for a reinforced hydrogen consuming Methane formation sewage sludge is used - by means of separation ( 4 ) after the thermo-pressure hydrolysis ( 2 ) and prehydrolysis ( 3 ) remaining coarse solids are separated, dried and pelleted; and the centrate obtained in the separation with water to a dry matter content of 3-5% and a NH ₄ content of max. Adjusted to a working temperature between 30-55 ° C and in a hydrolysis tank with acid-forming microorganism cultures is inoculated so that under anaerobic conditions, the formation of the acids required for biogas production takes place, with a pH correction to pH Values of 6.5-7.0 - the promotion of the pre-hydrolyzed substrate in the anaerobic pool-bed reactor ( 6 ) for biogas formation in a temperature range of 35-50 ° C in the upflow principle - by the external involvement of a micro or ultrafiltration stage ( 7 ) in the course of the anaerobic reactor ( 6 ) or more parallel or in series reactors from the reactor discharged, C-containing fission products and microorganisms are concentrated so that long-chain fission products and microorganisms are recycled into the biogas process - the separated filtrate through a floating bed column ( 8th ) was further purified under aerobic conditions and then thermally 9 ) at 60-75 ° to kill the microflora and in an ultrafiltration plant and the downstream one or two-stage reverse osmosis plant ( 11 . 12 . 13 ) - the remaining gas residues in the liquid (CH ₄ , CO ₂ , H ₂ S) via an upstream vacuum separator ( 10 ) are removed from the liquid at a negative pressure of -0.2 to -0.4 bar prior to ultrafiltration Plant for a process according to claim 1, consisting of a floating bed reactor column with anaerobic and aerobic working stages and integrated membrane stages for recycling organic residues into the decomposition stages and returning the purified water to the treatment process, comprising at least one separating means for non-organic impurities ( 0 ) as coarse separation - a rotary mixing and crushing system with homogenization ( 1 ) - a thermo-pressure hydrolysis unit ( 2 ) - a separation plant ( 4 ), such as press screws, decanters or vibrating screens - a drying and pelleting plant ( 5 ) - an enzymatic prehydrolysis ( 3 by incubation with microorganisms at 55 ° C - an anaerobic upwelling pool reactor ( 6 ) - an aerobic working stage used as a floating bed reactor ( 8th ) and equipped with floats having a density of 0.95-0.98 g / cm ³ and a diameter of 50-250 mm - a microfiltration ( 7 ) - an intensive ventilation for air entry ( 8.1 ) into the aerobic upstream floating bed ( 8th ) - a thermisation system ( 9 ) for the thermal treatment of the effluent from the aerobic floating bed reactor ( 8th ) - a degassing system ( 10 ) with CO ₂ removal to improve the ultrafiltration performance - ultrafiltration ( 11 ) - a return of the resulting concentrate in the anaerobic pool bed reactor ( 6 ) - a transfer of the filtrate to reverse osmosis ( 12 . 13 ) - a reverse osmosis UO ( 12 . 13 ) for concentrating the mineral components and returning the UO water to the thermo-pressure hydrolysis ( 2 ) and recovery of pure water - a membrane intensive entry and ventilation system ( 8.1 ) Installation according to claim 2, characterized in that in the course of the anaerobic reactor ( 6 ) a micro-ultrafiltration external ( 7 ) is switched. Installation according to claim 3, characterized in that it consists of polymeric or ceramic tube membranes with a tube diameter of 3-25 mm with a pore size of 0.05-0.4 microns, a flow rate in the tubes of 3-6 m / s , with pressure differences of max. 5.0 bar works, the filtrate pressure at pore widths of 0.05-0.4 microns against 0.4-0.8 bar, the backwash pressure is 0.5-1.0 bar above the transmembrane pressure and with a power loss> 50% reverse circulation with simultaneous backwashing. Installation according to claim 3, characterized in that it consists of polymeric winding membrane elements of PVDF, polysulfone, aromatic polyamides o. Polymer materials having a spacer of 30-120 mils (about 0.75-3.0 mm) with a cut-off of 10,000-150,000, preferably 20,000-100,000. Installation according to one of the preceding claims, characterized in that the water treatment from ultrafiltration ( 11 ) and 1-2-stage reverse osmosis system ( 12 . 13 ) consists. Installation according to claim 6, characterized in that the winding membrane elements used in the 1st stage of the reverse osmosis system (UO) have a spacer of 30-120, preferably 40-100 mils (about 1.0-2.5 mm). Plant according to claim 6, characterized in that the winding membrane elements used in the second stage of the reverse osmosis system (UO) have a spacer of 30-80, preferably 30-50 mil (about 0.8-1.2 mm). Plant according to one of the preceding claims, characterized in that in the aerobic reactor ( 8th ) a tangential distributor and baffles are attached. Plant according to one of the preceding claims, characterized in that the entry of the filtrate into the aerobic floating bed reactor ( 8th ) via a membrane intensive entry and ventilation system ( 8.1 ).

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