METHOD FOR TREATMENT OF BIODEGRADABLE MATERIALS AND DEVICE FOR CARRYING OUT THE METHOD

Description

[0001] The invention relates to a method for the treatment of biodegradable materials, in particular fermentation residues, poultry manure, pig manure or cattle manure, in which the biodegradable material is hygienized in a processor, in which during the hygienization in the processor volatile substances, in particular ammonia, are expelled from the biodegradable material and enriched in a gas mixture, in which the enriched gas mixture is withdrawn from the processor, fed to a purification stage and washed out of the gas mixture with a washing liquid in the purification stage, and in which the then ammonium-poor, biodegradable material is removed from the processor separately from the gas mixture and fed to a further use, wherein a negative pressure is applied in the processor,and wherein the volatile substances are extracted from the biodegradable material due to their respective partial pressure by the applied negative pressure. Furthermore, the invention also relates to a device for processing biodegradable materials, in particular fermentation residues, poultry manure, pig manure, or cattle manure, in particular for carrying out the aforementioned process.

[0002] DE 10 2016 118 761 A1 describes a processing method for biodegradable materials in which ammonia is to be removed from the biodegradable material. The ammonia is to be expelled from the biodegradable material with the addition of additives such as lime and fed into a gas mixture for purification. The expulsion takes place by separating, in particular isolating, the liquid or gas mixture from the solid by means of a chemical reaction. The ammonium compounds obtained during purification and the ammonium-poor, biodegradable material are then to be collected separately and, if necessary, further processed. Since, in addition to the lime, other additives such as polymers and electrolytes are usually added to the biodegradable material to enable pre-drying orSeparation of the solids from the raw liquid in order to then separate the ammonia from it means that the biodegradable material cannot be reused without restrictions after processing.

[0003] In US 2017 / 369345 A1, ammonia for nitrogen fertilizer production is to be extracted from biodegradable materials. For this purpose, the biodegradable material is fed to a degassing vessel. A vacuum pump is to be used to create a vacuum in the vessel, whereby the ammonia formed is extracted in a gas mixture and fed to at least one gas scrubbing device. It is essential for US 2017 / 369345 A1 that an acid required to scrub the ammonia is circulated. Furthermore, US 2017 / 369345 A1 discloses that the vacuum pump generating the vacuum is arranged downstream of the degassing vessel, in the direction of flow of the gas mixture, behind the gas scrubbing device, so that the generated vacuum is also present in the gas scrubbing device.

[0004] The gas scrubbing devices of US 2017 / 369345 A1, which are preferably connected in series, are due to the pressure drop caused by the selected connection and positioning of the vacuum pump, whereby in this design a complete reduction of the ammonia can only be guaranteed by the serial connection of several gas scrubbing devices.

[0005] The object of the invention is therefore to further develop such a process in such a way that the processed, biodegradable material can be reused in as many different ways as possible and that nitrogen compounds, such as ammonia in particular, can be separated as completely as possible.

[0006] This problem is solved in terms of method with the features of claim 1 and in terms of device with the features of claim 8. Further developments and advantageous embodiments are specified in the respective subordinate claims.

[0007] The process for the treatment of biodegradable materials, in particular fermentation residues, poultry manure, pig manure or cattle manure, in which the biodegradable material is hygienized in a processor, in which during the hygienization in the processor volatile substances, in particular ammonia, are expelled from the biodegradable material and enriched in a gas mixture, in which the enriched gas mixture is withdrawn from the processor, fed to a purification stage and the volatile substances are washed out of the gas mixture with a washing liquid during the purification stage, and in which the then ammonium-poor, biodegradable material is removed from the processor separately from the gas mixture and fed for further use, wherein a negative pressure is applied in the processor,and wherein the volatile substances are removed from the biodegradable material due to their respective partial pressure by the applied negative pressure, is characterized according to the invention in that the negative pressure applied to the processor causes a gradual pressure reduction in the processor, that due to the pressure reduction in the processor at a first pressure level due to the respective partial pressure, volatile substances, in particular ammonia, are expelled from the biodegradable material, that after the volatile substances have been expelled, the pressure in the processor is reduced to a second, lower pressure level, so that the boiling point in the processor shifts in such a way that water contained in the processor changes its state of aggregation and water vapor is formed in the processor,and that the water vapor produced in the processor is fed to a cooling unit as a gas mixture containing water vapor and that the water vapor is condensed in the cooling unit.

[0008] To create the negative pressure in the processor, a vacuum of up to 300 mbar, in particular up to 250 mbar, is preferably applied to the processor. The negative pressure present in the processor results in the removal of volatile substances, such as ammonia, from the biodegradable material. The separation of the volatile substances is thus carried out physically in the process according to the invention, so that previously necessary additives such as polymers or electrolytes can be dispensed with.

[0009] The biodegradable material is preferably thoroughly mixed in the processor for a residence time of at least 60 minutes. Temperatures of more than 70 °C in the processor also advantageously achieve sanitization of the biodegradable material.

[0010] The stages of the gradual pressure reduction in the processor are determined by the partial pressures of the individual components to be expelled from the biodegradable material. In the first pressure stage, volatile substances, particularly ammonia, are expelled from the biodegradable material by the pressure reduction in the processor based on the respective partial pressure. The volatile substances outgas from the biodegradable material according to their respective partial pressure, with the substances with the highest partial pressure outgassing first.

[0011] In an exemplary composition of a biodegradable material containing ammonia, hydrogen sulfide, and carbon dioxide as volatile substances, ammonia degasses first, then hydrogen sulfide, and finally carbon dioxide. Each of the aforementioned substances is assigned a pressure level at which temperature and pressure correspond to the substance to be evaporated according to its saturation vapor pressure curve, and the substance degasses from the biodegradable material. The individual pressure levels of the volatile substances are demarcated from one another to varying degrees depending on their respective partial pressures and sometimes merge seamlessly into one another. The greater the difference in the partial pressures, the clearer the pressure levels are.The first pressure stage can therefore consist of a number of individual pressure stages, with each of the first pressure stages having in common that the gas mixtures are fed to the purification unit. During the purification unit, the volatile substances are then washed out of the gas mixture using a scrubbing liquid. Another common feature of each first pressure stage is that the pressure in the purifier decreases further after the respective volatile substance has been degassed.

[0012] Furthermore, the negative pressure at the first pressure stage results in a larger proportion of the volatile substances extracted from the biodegradable material, particularly a larger proportion of ammonia, in the gas mixture withdrawn from the purifier. During further purification of this gas mixture with the scrubbing liquid, the gas mixture then has a significantly reduced volume compared to when the process is carried out at atmospheric pressure due to the negative pressure that is advantageously also present during the purification process. In particular, the volume of the gas mixture at the applied negative pressure is only 1 / 40 of the volume at atmospheric pressure. A system for purifying the gas mixture withdrawn at the first pressure stage can be dimensioned accordingly smaller.

[0013] After the volatile substances, particularly the ammonia, have been expelled, the pressure in the processor is reduced to a second, lower pressure level, so that the boiling point in the processor shifts such that the water contained in the processor changes its state of aggregation and water vapor is formed. The biodegradable material is then dried accordingly in the second pressure level. The water vapor generated in the processor is extracted from the processor as a water vapor-containing gas mixture, just as the ammonia-containing gas mixture was previously extracted. The water vapor-containing gas mixture is then fed to a subsequent cooling unit.

[0014] Although a large portion of the ammonia and other environmentally hazardous substances has already been removed from the biodegradable material in the first pressure stage or one of the first pressure stages, the water vapor-containing gas mixture may still be contaminated with ammonia and other suspended particles. To minimize potential environmental impacts, a further development proposes that the gas mixture be circulated between the purifier and the cooling unit, particularly in a closed circuit. This closed circuit ensures that even residual amounts of volatile substances, particularly ammonia, that are not subjected to purification with the scrubbing liquid do not enter the environment.

[0015] In the cooling unit, the water vapor is then advantageously condensed to separate it from the gas mixture. The remaining amounts of volatile substances, particularly ammonia, also condense along with the water vapor. The uncharged gas mixture returned to the processor from the cooling unit after the condensation of water vapor and volatile substances, particularly ammonia, can then be recharged with water vapor and residual ammonia in the processor.

[0016] The biodegradable material remains in the processor until it has a dry matter content of at least 79% to 82%. In contrast, the biodegradable starting material usually had a dry matter content between 8% and 11%.

[0017] The condensate from the cooling unit can be easily collected in a condensate reservoir. To separate the remaining volatile substances, especially ammonia, from the condensate, the condensate collected from the cooling unit can be evaporated according to a further development, whereby the water contained in the condensate is evaporated and impurities are separated from the water. The condensate is then easily transferred batchwise from the condensate reservoir for evaporation. This enables a simplified design and process, requiring only the condensate reservoir to be under vacuum, while the evaporation can take place at atmospheric pressure.

[0018] The part of the process operated under negative pressure is thus limited to all parts through which the gas mixture from the processor can flow, as well as the condensate reservoir.

[0019] During or before evaporation, sulfuric acid is advantageously added to the condensate, which reacts with the ammonia contained in the condensate to form ammonium sulfate. The evaporation concentrate thus produces an ammonium sulfate solution, in particular an ammonium sulfate solution with at least 80 percent strength.

[0020] The water produced as distillate during evaporation has a high purity, ideally 0 ppm, which can be remineralized by a hardening filter and returned to an economic cycle outside the process.

[0021] To accelerate the processing of the biodegradable material, a lime mixture can be added to the biodegradable material. The lime mixture is preferably added before the biodegradable material enters the processor for sanitization and drying. A mixer can be installed upstream of the processor for this purpose. The mixing of the lime mixture and the biodegradable material ensures a uniform, homogeneous mass with a consistent dry matter content.

[0022] The biodegradable material then reacts with the lime mixture in the processor, achieving a heat of at least 70 °C through mixing in the processor. Alternatively or additionally, the heat can also be generated using heating technology or waste heat from a previous process, such as a biogas plant, if not enough heat is generated from the process itself.

[0023] For further processing, the dry, biodegradable material removed from the processor can be pelletized for use as farmyard fertilizer, for example.

[0024] According to a further development, the dry, biodegradable material removed from the processor can also be mixed with ammonium sulfate obtained from the process during further processing. The ammonium sulfate can be obtained either from the purification of the ammonia extracted from the biodegradable material during the first pressure stage or one of the first pressure stages, or from the purified condensate. The mixing of the biodegradable material removed from the processor with the ammonium sulfate preferably takes place in a dosing container upstream of the pelletizing process, namely before the biodegradable material is pressed into pellets. Instead of mixing the ammonium sulfate with the biodegradable material, the ammonium sulfate can also be sprayed onto the pressed pellets, for example, prior to picking the finished pellets.

[0025] Furthermore, the invention also relates to a device for processing biodegradable materials, in particular fermentation residues, poultry manure, pig manure or cattle manure, in particular for carrying out the aforementioned method, with at least one processor which has a closed container with a mixer for receiving the biodegradable material and a removal device for low-ammonium, biodegradable material from the processor, and at least one purification device connected to the processor for a gas mixture which can be withdrawn from the closed container, comprising at least one washing column which is suitable for washing out ammonia and other volatile substances from the gas mixture, wherein a vacuum unit is assigned to the processor.This device is characterized in that the vacuum unit is arranged upstream of the purification device in the flow direction of at least one partial flow of the gas mixture to be withdrawn from the processor, that the vacuum unit has a cooling unit, and that the cooling unit has a condensate reservoir.

[0026] This vacuum unit allows a vacuum to be applied to the reprocessor's container, creating a negative pressure during the processing and / or sanitization of the biodegradable material. The negative pressure in the reprocessor causes volatile substances, such as ammonia and water vapor, to be successively removed from the biodegradable material. The volatile substances escape at different pressure levels depending on their volatility and partial pressures. The pressure level refers to the absolute pressure at which the respective component is extracted from the biodegradable material. What all pressure levels have in common is that they have an absolute pressure below atmospheric pressure.

[0027] According to the invention, the vacuum unit comprises at least one vacuum generator, in particular a vacuum pump, with which the negative pressure, in particular the vacuum, required in the processor, in particular in the processor's container, can be generated. Furthermore, the vacuum generator can advantageously operate not only the processor but also the subsequent purification device for the gas mixture drawn from the closed container under negative pressure. The negative pressure that can be generated with the vacuum generator is advantageously an absolute pressure of up to 300 mbar, in particular up to 250 mbar.

[0028] Furthermore, the vacuum unit can have at least one cooling unit. The water vapor extracted from the processor, in particular the water vapor-containing gas mixture, is introduced into this cooling unit and cooled until the water vapor condenses in the cooling unit. The condensate of the water vapor can then be easily separated from the gas mixture. Therefore, in a further embodiment, the cooling unit has at least one condensate reservoir for collecting the condensate.

[0029] To avoid environmental pollution, for example, from escaping gases during processing, a further development provides for a closed circuit for the gas mixture to be formed between the cooling unit and the closed container of the processor. In addition to minimizing environmental pollution, the circuit for the gas mixture allows it to be used multiple times as a transport medium for volatile substances, particularly water vapor, extracted from the biodegradable material. To transport the gas mixture from the cooling unit back to the processor, a recirculation fan can also be arranged in the circuit between the cooling unit and the processor.

[0030] According to a preferred arrangement, the cooling unit is arranged between the processor and the vacuum generator in the flow direction of at least a partial flow of the gas mixture to be extracted from the processor, in particular the gas mixture to be extracted from the processor at a first pressure stage. All volatile substances extracted from the processor as a gas mixture are thus passed through the cooling unit upstream of the vacuum generator. Depending on the respective pressure stage, the different gas mixtures are then passed on, with a gas mixture primarily laden with volatile substances such as ammonia being fed from the first pressure stage to the purification device, and a gas mixture primarily laden with water vapor being passed back to the processor via the circuit after the water vapor has condensed in the cooling unit.In particular, the gas mixture to be fed to the purification device, which mostly contains ammonia, can flow to the purification device via the vacuum pump.

[0031] According to a further development, an evaporator is connected to the condensate reservoir of the cooling unit to remove the ammonia condensed together with the water vapor from the collected condensate. The condensate is easily fed batchwise from the condensate reservoir to the evaporator. This allows for a simplified device design, requiring only the condensate reservoir to be under vacuum, but not the evaporator.

[0032] Highly pure water is produced as a distillate. This water can be remineralized through a water hardening filter and returned to the industrial cycle. The evaporation concentrate produces an ammonium sulfate solution of at least 80 percent, which can be used, for example, as a liquid fertilizer and can replace mineral fertilizers. The ammonium sulfate solution produced during evaporation can also be mixed with the ammonium sulfate solution obtained from the purification plant. Accordingly, the connected outlets for the resulting ammonium sulfate solution can be combined into a common dosing tank, storage tank, or buffer tank.

[0033] According to a further development, the purification device for a gas mixture enriched with volatile substances such as ammonia, which can be discharged from the closed vessel of the purifier, comprises at least one scrubbing column with at least one inlet and at least one outlet for the gas mixture to be purified, and at least one inlet for a scrubbing liquid. The gas mixture flows upwards in the scrubbing column, and the scrubbing liquid flows in the opposite direction, from top to bottom, so that the scrubbing column operates according to the countercurrent principle. The purified gas mixture can thus be discharged at an upper end of the scrubbing column, and ammonium sulfate can be removed at a lower end of the scrubbing column. Furthermore, better exchange between the scrubbing liquid and the gas mixture can be achieved by packing elements within the scrubbing column. A suitable scrubbing liquid is, for example, a water-sulfuric acid mixture with a pH value between 3 and 6.

[0034] In a preferred embodiment of the invention, at least two processors are connected in parallel. The two processors are preferably operated in an alternating mode. This alternating mode allows the processors to be operated alternately, whereby biodegradable material can be treated in one processor and another processor can be simultaneously charged and discharged. With two processors, double connections are then provided accordingly, and advantageously, two cooling units are provided, each connected to the processors. Two cooling units also allow biodegradable materials to be processed simultaneously in the two processors at different pressure levels.

[0035] Depending on the properties of the biodegradable material, pretreatment of the biodegradable material may be necessary. Such pretreatment may involve shredding and homogenizing the biodegradable material. For this purpose, a pretreatment unit for the biodegradable material may be installed upstream of the processor. A tool for shredding the biodegradable material may be located in the pretreatment unit. Furthermore, the pretreatment unit may also mix the biodegradable material or various biodegradable materials using a mixer.

[0036] In addition to any necessary comminution or homogenization, depending on the biodegradable material, the addition of a lime mixture may also be required to process the biodegradable material. According to a further development of the invention, a device for adding a lime mixture can therefore also be installed upstream of the processor. In addition to physically separating the volatile substances from the biodegradable material, the lime mixture also triggers a chemical reaction that enhances the process of expelling the volatile substances.

[0037] An advantageous design for the addition device is a screw conveyor, in which the lime mixture and the biodegradable material are mixed together. The lime mixture and the biodegradable material can then easily be assigned a common inlet opening into the closed container of the processor. Feeding via a screw conveyor ensures that a negative pressure is maintained in the processor, especially the closed container of the processor, even with continuous addition of biodegradable material. Preferably, in addition to the processor and the condensate reservoir, the purification device and the vacuum unit are also operated at negative pressure.

[0038] To ensure the legally prescribed temperatures required for sanitizing the biodegradable material in the processor, a heating device can be installed in the processor's closed container. External energy can then be supplied via this heating device, for example, waste heat from a biogas plant.

[0039] An embodiment of the invention, from which further essential features of the invention emerge, is illustrated in the drawing. The drawing shows a flow diagram of a device according to the invention.

[0040] The device comprises a total of two processors 1, 1', which are fed with biodegradable material via a common screw conveyor distributor 2, in particular alternately fed with biodegradable material. Each processor has a closed container 3, 3' in which the biodegradable material is mixed and sanitized. A vacuum generator 4 of a vacuum unit is assigned to the processors 1, 1'.

[0041] Between the respective processor 1, 1' and the vacuum generator 4, a cooling unit 5, 5' is arranged for each processor 1, 1', to which the volatile substances extracted from the biodegradable material in the processor 1, 1' are fed via corresponding line sections 6, 6'. These line sections 6, 6', together with line sections 7, 7', form a closed circuit between the respective processor 1, 1' and the respective cooling unit 5, 5'. A discharge line 8, 8' to a condensate reservoir 9 is also formed on each of the cooling units 5, 5'. This condensate reservoir 9 forms a buffer tank for a downstream evaporator 10. The evaporator 10, in turn, has separate discharge lines 11, 11' for an evaporation concentrate and for a distillate.

[0042] A purification device 12 is also arranged downstream of the vacuum generator 4 such that the vacuum generator 4 is arranged between the respective cooling unit 5, 5' and the purification device 12 in the flow direction of at least a partial stream of the volatile substances extracted from the biodegradable material. A cooling water circuit 13, 13' is also formed between the vacuum generator 4 and the cooling units 5, 5', which accordingly has a cooling water pump 14.

[0043] During operation of the device, a negative pressure of up to 300 mbar, in particular up to 250 mbar, can now be generated in the closed containers 3, 3' of the processors 1, 1', the cooling units 5, 5', and the purification device 12 using the vacuum generator 4. Ammonia, a volatile substance in a gas mixture, is now initially extracted from the biodegradable material fed to one of the processors 1, 1' via the conveyor screw distributor 2 when the absolute pressure in the closed container 3, 3' of the processor 1, 1' is reduced at a first pressure stage due to the partial pressure. For simplicity, the biodegradable material described in the exemplary embodiment contains only ammonia as a volatile substance. This ammonia-containing gas mixture is fed to the purification device 12 via the cooling unit 5, 5' and the negative pressure generator 4.In the purification device 12, designed as a scrubbing column, the ammonia is then scrubbed out of the gas mixture in countercurrent using a scrubbing liquid. If sulfuric acid is used as the scrubbing liquid, the ammonia then accumulates as an ammonium sulfate solution in the bottom of the scrubbing column. The purified gas mixture is thus released into the environment.

[0044] After the ammonia escapes from the biodegradable material, the absolute pressure drops to a second, lower pressure level due to the vacuum in the processor 1, 1'. At the second pressure level, the boiling point in the closed container of the processor 1, 1' shifts such that the water contained in the processor 1, 1' changes its state of aggregation from the biodegradable material, and water vapor is formed in the processor 1, 1'. This water vapor is also introduced into the respective cooling unit 5, 5' as a water vapor-containing gas mixture. In the cooling unit 5, 5', the water vapor is then condensed by the cooling water of the cooling water circuit 13, 13', whereby suspended particles and residual ammonia are also separated from the gas mixture.The gas mixture no longer loaded with water vapor is then fed back into the closed container 3, 3' of the processor 1, 1' via the respective line section 7, 7' and a recirculation fan 15, 15' arranged in the line section 7, 7'.

[0045] The biodegradable material can be dried via the circulating gas mixture. The dried material is then fed to a dosing container 17 via at least one screw conveyor 16.

[0046] The condensate accumulating in the cooling unit 5, 5' is fed into the condensate reservoir 9. In the condensate reservoir 9, the condensate is mixed with sulfuric acid via a corresponding feed line 18, whereby the ammonia contained in the condensate reacts with the sulfuric acid to form ammonium sulfate. The condensate is then fed batchwise to the evaporator 10. In the evaporator 10, the water contained in the condensate is evaporated until an ammonium sulfate solution of at least 80 percent is obtained.

[0047] The 80 percent ammonium sulfate solution is then fed via discharge line 11, together with the ammonium sulfate solution obtained in the bottom of the wash column of the purification device 12, to a buffer tank 19 or directly to a dosing tank 17. According to the invention, the dried biodegradable material is mixed with it in the dosing tank 17. The dried material is so dry that it is still in the pressing range even after mixing with the ammonium sulfate solution. From the dosing tank 17, the mixture of dried material and ammonium sulfate then passes via a dosing screw 20 into a press 21, where the mixture is pressed into pellets. Various post-treatment steps are then carried out downstream of the press 21 to remove dust and, if necessary, return it to the dosing tank 17.

[0048] In a first step, the pressed pellets are fed to a cooler 23 via a bucket elevator 22. Exhaust air from the cooler 23 then reaches a cyclone 24, where solids recovered in the cyclone 24 are returned to the dosing container 17. In a further step, the pressed pellets are screened in a screening unit 25. During screening, separated components, such as the solids from the cyclone 24, are then returned to the dosing container 17. Following the screening unit 25, a picking and loading station 26 is provided, where the pellets are packaged for further transport and use, for example, in big packs.

[0049] The dried material can also be pressed without adding ammonium sulfate solution. Instead of feeding it into the dosing tank 17, the entire ammonium sulfate solution produced by the evaporator 10 and the purification device 12 is fed into the buffer tank 19, from which it is sprayed onto the finished pellets either in a separate filling station 27 or in an intermediate third step prior to picking and loading 26.

[0050] Depending on the properties of the respective biodegradable material, pretreatment may be necessary. Therefore, a pretreatment unit 28, formed by a container 29 with a mixer, is located upstream of the screw conveyor distributor 2 in the flow diagram.

[0051] Furthermore, the pretreatment unit 28 has a weighing device 30 associated with the container 29. The pretreated biodegradable material then passes via a slide and a screw conveyor 31 to the screw conveyor distributor 2. The screw conveyor 31 also has an addition device 32 for adding a lime mixture.

Claims

1. Process for treating biodegradable materials, in particular fermentation residues, poultry manure, pig manure or cattle manure, in which the biodegradable material is hygienized in a conditioner (1, 1'), in which, during the hygienization in the conditioner (1, 1'), volatile substances, in particular ammonia, are expelled from the biodegradable material and are enriched in a gas mixture, in which the enriched gas mixture is drawn off from the conditioner (1, 1'), is fed to a purification process and the volatile substances in the purification process are washed out of the gas mixture with a washing liquid, and in which the biodegradable material, which is then low in ammonium, is removed from the conditioner (1, 1') separately from the gas mixture and is fed to a further use, wherein a negative pressure is present in the conditioner (1, 1'), and wherein the volatile substances are removed from the biodegradable material on the basis of their respective partial pressure by the negative pressure present, characterized, in that the negative pressure applied to the conditioner (1, 1') causes a stepwise pressure reduction in the conditioner (1, 1'), in that the pressure reduction in the conditioner (1, 1') at a first pressure level causes volatile substances, in particular ammonia, to be expelled from the biodegradable material on the basis of the respective partial pressure, that, after the volatile substances have been expelled, the pressure in the conditioner (1, 1') is lowered to a second, lower pressure stage, so that the boiling point in the conditioner (1, 1') shifts in such a way that water contained in the conditioner (1, 1') changes its aggregate state and water vapor is formed in the conditioner (1, 1'), 1'), that the water vapor formed in the conditioner (1, 1') is fed to a cooling unit (5, 5') as a gas mixture containing water vapor, and that the water vapor is condensed in the cooling unit (5, 5').

2. Method according to claim 1, characterized in that the gas mixture is circulated between the conditioner (1, 1') and the cooling unit (5, 5'), in particular in a closed circuit.

3. Method according to claim 1 or 2, characterized in that the condensate from the cooling unit (5, 5') is collected and evaporated, whereby the water contained in the condensate is vaporated and impurities are separated from the water.

4. Process according to one of claims 1 to 3, characterized in that sulphuric acid is added to the condensate for or before evaporation.

5. Process according to one of the preceding claims, characterized in that a lime mixture is added to the biodegradable material.

6. Method according to one of the preceding claims, characterized in that the biodegradable material removed from the conditioner (1, 1') is pelletized.

7. Process according to one of the preceding claims, characterized in that the biodegradable material removed from the conditioner (1, 1') is mixed with ammonium sulphate obtained from the process.

8. Apparatus for conditioning (1, 1') biodegradable materials, in particular fermentation residues, poultry manure, pig manure or cattle manure, in particular for carrying out the process according to claims 1 to 9, having at least one conditioner (1, 1') which has a closed container (3, 3') with a mixing mechanism for receiving the biodegradable material and a removal device for low-ammonium, biodegradable material from the conditioner (1, 1'), comprising at least one purification device (12) adjoining the conditioner (1, 1') for a gas mixture which can be extracted from the closed container (3, 3'), having at least one washing column which is suitable for washing ammonia and other volatile substances out of the gas mixture, wherein a vacuum unit is associated with the conditioner (1, 1'), characterized in that the vacuum unit of the purification device (12) is arranged in the flow direction of at least a partial flow of the gas mixture to be extracted from the conditioner (1, 1'), that the vacuum unit has a cooling unit (5, 5'), that the cooling unit (5, 5') has a condensate reservoir (9), and that the vacuum unit has at least one vacuum generator (4), in particular a vacuum pump.

9. Device according to claim 8, characterized in that a closed circuit for the gas mixture is formed between the cooling unit (5, 5') and the closed container (3, 3') of the conditioner (1, 1').

10. Device according to one of claims 8 or 9, characterized in that the cooling unit (5, 5') is arranged between the conditioner (1, 1') and the vacuum generator (4) in the direction of flow of at least a partial flow of the gas mixture to be withdrawn from the conditioner (1, 1'), in particular of the gas mixture to be withdrawn from the conditioner (1, 1') at a first pressure stage.

11. Device according to one of claims 8 to 10, characterized in that an evaporator (10) is connected to the condensate reservoir (9) of the cooling unit (5, 5').

12. Device according to one of claims 8 to 11, characterized in that a heating device is assigned to the closed container (3, 3') of the conditioner (1, 1').

13. Apparatus according to one of claims 8 to 12, characterized in that a pretreatment unit (28) for the biodegradable material is connected upstream of the conditioner (1, 1').

14. Apparatus according to one of claims 8 to 13 in that an addition device (32) for a lime mixture is connected upstream of the conditioner (1, 1').