FI20185183A1 - Reactor for producing biogas from biomass using anaerobic digestion - Google Patents

Abstract

The invention relates to a reactor for the production of biogas from biomass by anaerobic decomposition, which comprises - a duct-like body (12) of vertical model limiting within it a reactor space (14) for vertically directed piston flow of biomass, which body (12) comprises at least three consecutive blocks (24) with microbe strains, - feeders (25) arranged at the upper end (13.1) of the body (12) to feed biomass into the body (12), - mixer (20) to mix the biomass (16) and feed the microbes in the biomass (16) arranged at least partially inside the body (12), - collecting means (22) for recovering the biogas that arises, - a bottom cone (17) joined to the lower end (13.2) of the body (12) for collecting sediment , - means (27) for removing sediment arranged at the lower end (13.2) of the body (12), for removing sediment to the lower end (92) of the bottom cone (17), - an outer skeleton (50) arranged outside the body (12) to support mare from the outside (12) against a hydrostatic pressure which arises within the body (12).

Description

REACTOR FOR THE PRODUCTION OF BIOGAS FROM BIOMASS BY ANAEROBIC

in the diffusion of

20185183 PRH 27-02-2018

The invention relates to a reactor for the production of biogas from 5 biomass by anaerobic digestion, comprising

- a body comprising two ends, namely an upper end and a lower end, delimiting inside a reaction space for biomass, which body is channel-like for the plug flow of biomass and which body comprises at least three successive blocks with microbial strains,

- feeding means arranged at the upper end of the hull for feeding biomass inside the hull,

- mixing means for mixing the biomass and feeding the microbes into the biomass, at least partially inside the hull,

- recovery means for recovering the resulting biogas as the microbial consumption of biomass organic material, and

- solids removal means fitted to the lower end of the body 20 to remove solids.

The invention relates to reactors for the production of biogas from biomass. Biogas production is a method of treating organic waste and a method of producing renewable energy. Biogas production 25 is based on a biological process known as anaerobic digestion. In anaerobic decomposition, microbes decompose organic matter, ie biomass, under anaerobic conditions, so that the final product is biogas containing methane. Anaerobic degradation is a multi-stage process in which several different microbes are involved in different stages of the digestion chain, as shown in Figure 1. Decomposition chains for decomposing biomass can be described in a simplified way as follows:

1) Polysaccharides (carbohydrates) -> Sugars -> Short chain fatty acids, H2, CO2 -> CH4, CO2

2) Proteins -> Peptides, amino acids -> Short chain fatty acids, H2, CO2 -> CH4, CO2

3) Lipids

-> Long chain fatty acids -> Short chain fatty acids, H2, CO2 -> CH4, CO2.

Described step by step, for example, the degradation chain of cellulose contained in lignocellulose is as follows:

20185183 PRH 27-02-2018

1) In hydrolysis, the breakdown of cellulose into sugars: (CeHioOsjn + nH2O -> nCeH ^ Oe

2) In acid fermentation, the breakdown of glucose units into acetate:

C ₆ Hi ₂ O ₆ + 4H ₂ O -> 2CH3COO- + 2HCO3- + 4H ⁺ + 4H ₂

3) In methanogenesis, decomposition of acetate to methane 2 2 CH3COO- + H2O -> CH ₄ + HCO3-

4H ₂ + HCO 3 - + H ⁺ -> CH ₄ + 3 H ₂ O

At different stages of the digestion chain, active microbes also have different optimum conditions. The biogas produced as a final product of anaerobic digestion25 can be utilized as renewable energy, for example in the production of electricity and / or heat or as a transport fuel.

Traditional biogas technology is mainly designed to treat 30 wet waste fractions such as sewage sludge and animal manure. The treatment then most often takes place in fully mixed vertical (vertical) cylindrical tank reactors at a low dry matter content (most often <10%), i.e. at a high water content (> 90%). The most significant problem with this process is that more than 90% of the feedstock inside the reactor is water. Water does not produce energy (biogas), but instead heating large amounts of water 5 consumes considerable amounts of energy. In addition, if it is desired to treat drier waste fractions in this type of fully stirred reactor, the feed must be diluted with liquid. It is also possible to recycle the liquid back to the reactor, but this involves several problems, including the inhibitory effect of decomposition products and nitrogen compounds accumulating in the recycled liquid. A further problem with the use of a fully mixed tank is that all microbial strains live in the same state under homogeneous conditions, in which case the reaction conditions must be optimized according to the slowest stage of the decomposition chain, i.e. methane formation. In this case, the activity of the active microbes in other stages of the digestion chain is not optimal.

So-called dry process-based biogas technologies have been developed for the treatment of drier waste fractions. These processes can be operated at a significantly higher dry matter content than traditional biogas technology. In this case, a significantly higher energy yield per reactor volume can be achieved.

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One way to implement a dry process-based biogas plant is a so-called plug-flow biogas reactor. A plug-flow biogas reactor is most often a horizontal (horizontal) tank reactor into which biomass is fed from one end of the reactor and the treated material is removed from the other end of the reactor. Thus, during the treatment, the material passes through the plug through the entire horizontal reactor. A plug-in biogas reactor can be operated at traditional biogas processes at a significantly higher rate4

20185183 PRH 27-02-2018 in the dry matter content (for example 10 - 30% in the dry matter content). The process thus enables a broad raw material base also through the possibility of handling drier materials, as well as a higher energy yield per reactor volume and the most compact reactor structures. The process has less water than conventional high water processes to take up the reactor volume, which means that there is also more decomposable organic matter per reactor volume in the process.

A horizontal plug reactor for producing biogas disclosed in WO 2015/075298 A1 is known from the prior art. However, the problem with such a biogas reactor is that the digestate and other solids left in the reactor are removed from the end of the horizontal reactor. At this point, heavier material, such as glass, metal, and aggregate, that accompanies the raw material begins to accumulate and accumulate at the bottom of the reactor throughout the 15 reactor journey. The heavy material complicates the operation of the mixers in the reactor with horizontal mixing shafts, when the mixers have to transfer not only the material to be decomposed but also the non-decomposable and heavy solids.

Furthermore, the removal of solids is problematic, because when the digestate is removed from the reactor by means of a vacuum, the solid can clog the discharge connection.

It is also an object of the invention to provide a more reliable reactor for producing biogas from biomass than prior art reactors, in which reactor the heavier and non-degradable material accompanying the raw material does not cause problems. The characterizing features of the present invention appear from the appended claim 1.

By limiting the reactor of the reactor according to the invention, which comprises the upper end of the body and the other end, the object can be achieved comprising two ends, namely including the biomass of the reaction space.

20185183 for PRH 27-02-2018, which body is vertically channel-like for vertical plug flow of biomass and comprising at least three successive blocks with microbial bases, an external support frame fitted outside the body to support the body 5 from the outside and a narrower lower end, connected to the lower end of the body to collect solids. In addition, the reactor includes feed means arranged at the upper end of the body for feeding biomass into the body, mixing means for mixing the biomass and feeding microbes at least partially inside the body, recovery means for recovering the resulting biogas. .

In such a reactor, the biomass is moved by gravity as a plug flow downwards in the reactor towards the discharge means, and at the same time the non-degradable solid accompanying the biomass is automatically transferred in the reactor towards the discharge means. In this way, the solids automatically end up by gravity through the bottom cone at the lower end of the body to the discharge means and further out from inside the reactor body. In this case, the adverse effects of the solid accumulating inside the reactor, such as clogging and reduction of the reaction volume, can be avoided. On the other hand, when arranged vertically, the reactor according to the invention takes up considerably little base area from the production plant and the production capacity can be easily increased by placing the reactors according to the invention in parallel. When using an external support frame, the reactor body can be quite light in structure, as the outward force caused by the hydrostatic pressure acting inside the body can be received by the external support frame supporting the body without thickening the reactor body.

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Preferably, the mixing means includes a reject collection and feeding system for collecting the reject from the blocks and feeding it to the at least three blocks as a thick mass. With such a reactor, the operating conditions of the microbes used in each anaerobic digestion reaction can be optimized by adjusting the conditions of that block. Optimized conditions enhance microbial activity and thereby accelerate the decomposition of biomass to the desired end product, methane. The reject collection and feeding system allows the strong microbial strain contained in the reject to be fed as a thick stock in front of the block, which ensures a sufficient microbial strain at the very beginning of that block. By feeding the reject to each block, the motor power required by the mixing means can also be reduced.

Preferably, the mixing means are implemented on axes transverse to the vertical direction of the reactor body for mixing the biomass on a block-by-block basis. The transverse axis allows each block to be mixed independently, regardless of the number of consecutive blocks.

Preferably, the reject collection and feeding system is adapted to feed the reject as a thick mass through mixing means to reduce friction. At the same time, the microbial strain can be transferred from the end of the block to the beginning or, if necessary, from one block to another. If necessary, the same feed devices can be used to feed a special feed to the reactor, which is not profitable to feed to the initial end of the reactor, where the conditions are not optimal for the special feed to be fed.

The reject collection and feed system may include a thick pulp pump to feed the reject at a dry matter content of 3 to 35%, preferably 15 to 25%. In this case, the reject contains sufficient solids, on the surface of which, for example, methane

20185183 PRH 27-02-20188 genes, ie the microbial strain responsible for methane formation, generally live.

According to one embodiment, the support and use of the mixing means 5 of each block are located outside the body. In this way, the maintenance of the mixing means can be performed from outside the reactor, which greatly facilitates the maintenance.

Preferably, the reaction space is divided into blocks for each reaction step of anaerobic digestion, comprising at least a hydrolysis block, an acid fermentation block and a methanogenesis block. In this way, the conditions of each block can be optimized for that particular reaction to optimize biogas production. Preferably, the length of the hydrolysis block is 25 to 35% of the total length of the reaction space, the length of the acid fermentation block is also 25 to 35% and the length of the methanogenesis block is 30 to 50% of the total length of the reaction space.

When talking about a block-specific microbial strain, it should be understood 20 that each block has a mixed population of microbes from different blocks. In the hydrolysis block, the strain of microbes essential for hydrolysis is 50 to 95% of the number of all microbes, as in the acid fermentation block. The microbial strain of a methanogenesis block is more sensitive and therefore the microbial strain corresponds to 30-90 25% of the total microbial strain of that block.

Preferably, the reactor further comprises independent thermal control means for controlling the temperature of the biomass on a block-by-block basis. In this way, the temperature of the biomass can be adjusted more precisely, which facilitates the optimization of the conditions.

Preferably, the external support frame is adapted to support the blocks with each other. The external support frame ensures the overall rigidity of the reactor structure and the support required for the attachment points of the agitator shafts.

Preferably, the reactor includes means for independently monitoring and controlling the inoculation, agitation and heating of each block. In this way, each block can be controlled independently of the other blocks.

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According to one embodiment, the reactor comprises second supply means 10 for supplying biomass and / or biogas from the walls of the reaction space to the biomass to facilitate the flow. By feeding a thick mass or biogas, the friction between the reactor body and the biomass can be reduced and at the same time the biomass is inoculated.

Preferably, the reactor comprises biogas recirculation means combined with recovery means for recirculating the recovered biogas under pressure to the other, i.e. lower end of the reactor body, to mix the digestate and to remove the biogas from the digestate. By means of the recycling means, the digestate is mixed, whereby the biogas trapped in the digestate can be released and rise upwards in connection with the upper end of the reactor body to a gas space from which it can be further recovered.

The biogas recirculation means may include a flow passage 25 for connecting the recovery means to the lower end of the reactor body to recycle the biogas and a pump adapted to the flow channel to suck the biogas from the recovery means and pressurize the recyclable biogas before the biogas is fed into the reactor body.

Preferably, the reactor body comprises sub-bodies which, except for their length and height, are identical to each other. Such a structure makes the reactor advantageous to manufacture.

20185183 PRH 27-02-2018

Preferably, the subframe includes planar modules that are identical to each other in each subframe. The modular reactor can be easily packed in sea containers for transport 5 and can be installed very quickly at the installation site.

Preferably, the subframes form a direct flow channel that acts as a reaction space. The vertical channel-like structure allows the biomass to propagate as a plug flow.

According to one embodiment, the slurry pump is a hydraulically operated piston pump. Such a pump is particularly well suited for pumping thick stock. 15

There may be at least 3, preferably 3-6 blocks. In this case, there is at least one block for each main decomposition reaction, and the conditions of each block can be optimized for each microbial strain. 20

In this context, when talking about blocks, it is to be understood that the blocks disclosed in this application are parts of a reactor, each having its own main microbial base, each of which is preferably controlled independently. A single block may include one of 25 sub-frames and mixing means consisting of modules. The boundaries of the blocks may vary depending on the reaction zones caused by the biomass to be fed. Preferably, the block boundary refers to the area where the main population of the microbial population changes from one population to another. Preferably, there are no mechanical constraints between the blocks 30, such as partitions or the like, but the feed biomass can pass through the reactor without passing through the different blocks. Preferably, different conditions prevail in each block. In addition, it should be understood that when referring to biomass, the raw material fed to the reaction space and anaerobically degraded there refers to the digestate and the reject as the final mass of the anaerobic digestion product leaving the reaction space.

Preferably, the biogas recovery means are arranged in connection with the upper end of the reactor body. In the reactor, the biogas rises in the liquid bed formed by the biomass and can be most easily removed from the upper end of the reactor, i.e. the upper end.

According to a preferred embodiment, the external support frame is a separate steel truss structure. Such a support frame is easy to transport unloaded to the place of use and assembled on site. On the other hand, the steel truss beam structure 15 is quite light with respect to its stiffness. In other words, the external support frame is not part of the frame but a separate entity with respect to it.

According to another embodiment, the outer support frame is made of fibrous concrete. It is possible to print the fiber concrete in 3D, which means that no manual welding work is required in the manufacture of the support frame.

20185183 PRH 27-02-2018

According to one embodiment, the reactor body is made of 4 25 20 mm thick steel plate. In this case, the reactor body is quite light and it is advantageous in terms of material costs to implement it when the required strength is provided by a separate support frame outside the body.

Alternatively, the reactor body may be a 3D cast structure made of fiber-reinforced concrete with a thickness of 100 to 400 mm. When made with the help of fiber concrete, considerably little manual welding work is required in the manufacture of the reactor body.

20185183 PRH 27-02-2018

Preferably, the height of the reactor body is 2 to 4 times the width or length of the reactor. In this case, the reaction volume can be large in relation to the floor area used, the volume of the reactor being oriented mainly vertically. 5

The reactor according to the invention can be used for the production of biogas from biomass by anaerobic digestion as a process in which biomass is fed as feed to the reaction by mechanical feeders and at the same time the biomass in the reaction state is pushed forward vertically downwards. The biomass is mixed on a block-by-block basis in a reaction zone divided into successive blocks to feed the biomass to the block-specific microbial strains and to advance the biomass in a reaction space of at least three blocks comprising its own main microbial strain. Biogas resulting from the anaerobic digestion of biomass is recovered. The microbial strain of each block is fed before the corresponding block, and in at least two of these blocks the feed takes place as a thick mass as a reject from the block. By block-specific control of the conditions, each anaerobic decomposition reaction can be performed under more optimal conditions than the prior art methods. In this context, the word above means the beginning of the block, i.e. the opposite direction in the direction of flow of the biomass. The location where the microbial strain is fed determines the beginning of the block25, as the microbial strain is significantly enhanced at this point. The object of the invention is achieved because feeding the microbial strain in front of each block strengthens the concentration of the microbial strain and considerably accelerates the growth of the microbial strain to the optimum in that block, which in turn enhances the microbial reactions and thus the biogas production.

Preferably, the microbial strain is recycled within the block from end to end of the block as a reject. Recycling moves the strong microbial population at the end of the block to the beginning of the block, where the microbial population is inherently weak.

The reject can be fed back in front of the block, to the suction valve bricks through the reject collection and feeding system at regular intervals to keep the reject collection and feeding system clean. Back feed can effectively prevent clogging of the collection system. In other words, the reject can sometimes be fed back through the discharge connection to the 10 blocks from which the reject is taken.

The mixing means may be rotating vane members and in the direction of travel of the biomass the mixing means of the last block are used in the opposite direction to the mixing means of the other blocks.

The opposite mixing direction facilitates the release of biogas gas bubbles generated in methanogenesis from the biomass solid.

20185183 PRH 27-02-2018

Preferably, the biomass is inoculated by rotating the mixing means 20 backwards. In this context, the word backwards means that the mixing means are rotated so that their biomass-transferring force is directed towards the upper end of the reactor, from which the biomass is at least mainly fed to the reactor. By transferring the decomposable biomass backwards in the reactor, it is possible to ensure the spread of 25 microbial strains into the decomposable raw material and the mixing of the decomposition products away around the microbes.

According to one embodiment, the liquid feed is fed to the reactor via mixing means. Thus, the feed can be fed to a selected location in the reactor according to the processing time required for the feed. In other words, for example, the first block of the reactor can be omitted for a feedstock that is easily degradable, thus shortening the residence time of the biomass in the reactor.

Preferably, the temperature of the biomass in each block is adjusted on a block-by-block basis. Block-specific temperature control allows for more accurate optimization of conditions, which enhances biogas 5 production. In this context, temperature control can mean either heating or cooling of the biomass depending on the conditions. Preferably, the biomass fed to the reactor needs heating and heat can be recovered from the biomass to be removed at the end of the reactor, i.e. cooled, for example to preheat the feedstock.

The inoculation and heating of each block can be monitored and controlled independently. In this way, it can be ensured that each anaerobic decomposition reaction can take place under conditions favorable to the reaction. By means of independent control, the blocks and thus also the reaction conditions are at least almost independent of each other.

20185183 PRH 27-02-2018

According to another embodiment, 20 biogas can be fed from the walls to facilitate the flow of biomass. Biogas effectively removes biogas bubbles from the walls of the reaction space inside the biomass. This is especially important in the last block of the reactor, as the method prevents the biogas from escaping with the digestate. 25

In the reactor according to the invention, the mixing is carried out by mixing the biomass in the reaction space of the reactor on a block-by-block basis. The advantage of this mixing method is that the reactor can be mixed block by block by locally moving the mass forwards or backwards. It is possible to control the operation of each mixer separately, i.e. the power and direction of the mixing as well as the reactor temperature (between 20 and 55 ° C) can be adjusted block by block. Reactor conditions (including pH, temperature, gas production) can be monitored in real time locally and on a block-by-block basis (sensors in the area of each block) and the data obtained can be compared to agitation and reactor load. By moving the microbial strain of at least two blocks as a thick mass reject in the direction of biomass flow backwards in front of the block, a sufficiently large population of the microbial strain in the whole block is ensured. The difference with biogas reactors based on the longitudinal mixing axis is that the microbial strain can be moved locally and block by block backwards in the reactor, thereby strengthening the active microbial strain locally in the 10 stages of anaerobic digestion in that block. At the same time, the reactor conditions can be optimized on a block-by-block basis! and it is possible to optimize the conditions locally according to the optimal conditions of the microbes associated with the different stages of the digestion chain. 15 In this case, a better decomposition result can be achieved and the biogas yield is maximized.

20185183 PRH 27-02-2018

The reactor feed means may be arranged in connection with the hull so that the feed means feed biomass below the liquid surface inside the reactor hull 20. This ensures that no air enters the feed, which interferes with the microbial population of anaerobic digestion.

The structure of the reactor according to the invention is preferably based on prefabricated modules. By modules is meant concrete plate-like parts of the hull, which are combined to form channel-like subframes which, when placed in succession, form the reactor body. Advantages of a biogas plant based on prefabricated modules include the fact that the plant size is easily scalable (increasing the number of subframes and increasing the length, ie adjusting the reactor size), the plant is quick to install and commission on site (compared to traditional biogas plant solutions, often cast in concrete molds). on-site) and in the production of standard-sized modules, it is possible to achieve serial work, which reduces manufacturing costs. Furthermore, the modules allow easy transport of the reactor using standard sea containers. In this context, when talking about subframes, we mean a concrete structure forming a frame, in which the modules form a reaction space inside the subframe, while when talking about blocks we mean a structure independent of regulation and control, which may consist of one or more subframes.

The reactor according to the invention is capable of decomposing up to about 9-12 kg of organic matter equivalent amount of biomass per one cubic meter of reactor volume per day (9-12 kg VS / m ³ / d). This amount can vary considerably depending on the characteristics of the input 15. The benefit of the reactor according to the invention can be determined, for example, by producing a considerably smaller reactor than would be required by the reactors according to the prior art.

The invention will now be described in detail with reference to the accompanying drawings, which illustrate some embodiments of the invention, in which:

20185183 PRH 27-02-2018

Figure 1 shows the principle of anaerobic decomposition of biomass25 from raw material to final product,

Figure 2 shows a schematic side view of a reactor according to the invention,

Figure 3 shows a schematic end view of a reactor according to the invention,

Figure 4 shows a schematic side view of a reactor according to the invention,

Figure 5 shows a process diagram of an embodiment of a reactor according to the invention,

20185183 PRH 27-02-2018

Figure 6 shows the assembly of a reactor according to the invention in principle.

As shown in Figure 1, anaerobic digestion as a process involves 5 several steps 100 in which microbes degrade organic matter. Since each reaction takes place best under the optimum reaction-specific condition, the efficient utilization of anaerobic digestion for biogas production largely depends on the optimization of the stages of the different sub-processes. Under the preferred conditions for the hydrolysis 102 and fermentation of the polysaccharides 10, the pH is about 6.5 to 7. Under the preferred conditions for the fermentation of the sugars 104, the pH is about 5 to 6.

Under the preferred condition of acetic acid formation 106, the pH is about 6.5 to 7.5. Under conditions favorable to methane formation 108, i.e., methanogenesis, the pH is about 6.5 to 8.0. A microbial strain essential for methanogenesis dies if the pH is below 6. In addition, the hydrolysis step benefits from having a low oxygen content in the pulp, while oxygen is highly toxic to the microbes in the methanogenesis step. In addition, microbes in the methanogenesis and aceto20 genesis stages are very sensitive to the accumulation of inhibitory substances (e.g. short-chain fatty acids, ammonia). The temperature used in the process may be, for example, 35 to 37 ° C or about 55 ° C. However, the temperature may vary depending on the feed and the microbial strain used. Since the biomass used as a feedstock in process 25 can vary considerably in its composition, the reactions involved in anaerobic digestion can also vary.

The structure 30 of the reactor according to the invention will now be described in more detail. According to Figures 2 and 4, the reactor 10 according to the invention consists of a modular body 12. More specifically, the modular body 12 preferably comprises 3 to 10 sub-bodies 46 which vertically form a channel-like body 12 of the reactor 10, confining a reaction space 14 in which biomass

20185183 PRH 27-02-2018 is decomposed through anaerobic decomposition into biogas and digestate. If necessary, there can also be considerably more than ten subframes. The sub-bodies 46 are channel-like structures of similar diameter and shape, and only the length of the sub-bodies 46 in the direction of flow of the biomass, i.e. in the vertical direction of the reactor, can vary. The subframes can be, for example, 2.2 m wide and long, in which case only the height of the subframes and the number of subframes vary according to the volume required from the reactor. The height of the sub-body 10 can be, for example, 3 m. The vertical direction of the reactor 10 in this context means the same direction as the direction of flow of the biomass 16 propagating in the plug space in the reaction space 14. The modules forming the sub-bodies can be pre-machined, surface-treated and insulated. Preferably, the subframes 46 are locked in place by the external support frame 50 shown in Figures 2 and 4 belonging to the reactor 10 and sealed to each other by seals or welding. A separate external support frame 50 locks the subframes 46 into a unitary body 12 of the reactor 10. The subframes 46 may be in the form of, for example, squares and the cross-section of the reaction space 14 delimited by them may also be rectangular or square. On the other hand, the cross-section of the reaction space can also be some other shape, such as circular, but in this case a vertical axis of the mixing means has to be used, to which the mixing means 25 of the different blocks are connected, for example by means of a switch.

The outer support frame 50 is preferably a steel-structured truss beam structure 94 as shown in Figure 4, in which the beams are welded to the truss pattern to provide a rigid structure 30. Preferably, the lattice beam structure 94 comprises two vertical sections 94.1 on either side of the reactor 10 body 12 and a horizontal section 94.2 connecting the vertical sections 94.1. Both vertical parts 94.1 are supported on the outer surface of the reactor 10 body 12 from the side. Hydrostatic pressure acting inside the reactor vessel

20185183 PRH 27-02-2018 tends to push the reactor walls outwards, but the counterforce provided by the external support frame acts as a counterforce to this. For example, the external support frame can be attached to a floor slab formed under the reactor or bolted to the floor of the production space 5, whereby the vertical parts of the support frame cannot move horizontally. The beams of the truss beam structure can be, for example, hollow pipes that are welded together. In this case, the structure is inexpensive in terms of material costs, but still very rigid. The use of an external support frame allows the implementation of the 10 reactor hull as a rather thin structure, which would be impossible without the external support provided by a separate external support frame. Alternatively, for the steel truss beam structure, the external support frame can also be formed as a wire structure. 15

In addition to the body 12 and the external support frame 50, the reactor 10 includes a bottom cone 17 which collects the solid transported downwards in the reactor, i.e. the digestate and the non-degradable material accompanying the biomass, such as glass, metals and rock 20. The bottom cone 17 comprises an upper end 90 with a dimension corresponding to the lower end 13.2 of the reactor 10 body 12 and a narrower lower end 92 to which the outlet means 27 of the reactor 10 are attached. The conical shape of the bottom cone collects the solid inside the body so that it ends up at the outlet scrapers. By means of the solids removal means 27, the rot and other solids accumulating on the bottom of the reactor 10 are removed through the bottom cone 17. The solids removal means 27 can be, for example, a screw conveyor, by means of which the solids 30 can be transferred away from inside the reactor body.

In addition to the solids removal means 27, the reactor 10 includes feed means 25 for feeding biomass inside the body 12 of the reactor 10 to the liquid surface in the reaction space 14.

20185183 PRH 27-02-2018 below. The feeding means 25 may be mechanical, such as a screw conveyor or the like, which feeds the biomaterial inside the first subframe 46. In connection with the screw conveyor 25.1, a feed hopper 25.2 can be included, through which raw material is fed to the screw conveyor 25.1. The feed means and the solids removal means may be on the same side of the body, whereby the bottom surface area required for the reactor as a whole is still smaller than by placing the feed means and the solids removal means on opposite sides. 10

As shown in Figure 2, the reactor 10 also includes mixing means 20 arranged at least partially inside the body 12, by means of which the mixing means 20 are used to mix the biomass 16 as a raw material inside the body 12. According to the invention, each block 24 preferably includes its own mixing means 20, which may be, for example, paddle mixers 36 supported by a shaft 48 transverse to the vertical of the reactor 10 as shown in Figure 3. Block 24 refers to a controllable and controllable unit 20 for one or more subframes 46. adjust the main microbial population in the area of the block to be suitable for microbial activity. According to a preferred embodiment of the invention, each block 24 comprises at least one separate paddle mixer 36, whereby the mixing of the biomass 16 can be controlled on a block-by-block basis. Alternatively, instead of paddle mixers, for example, a mixing screw or similar mechanical means or a combination of paddle mixer and screw can be used to move the biomass in the reaction space in different directions, also axially. As shown in Figure 2, there may be a number of paddle mixers 36 corresponding to the number of subframes 46. In this case, the number of blocks 24 can also be the same.

Figure 3 shows the reactor according to the invention in a vertical sectional view of the end. Preferably, in the reactor 10, the support of the stirring means 20 can also be arranged in connection with the external support frame 50 of Fig. 4. In this case, the drive motor and gearbox 66 of each paddle mixer 36 and the bearings 64 of the shafts 48 are located outside the body 12 5 of the reactor 10. This greatly facilitates the maintenance of the mixing means 20.

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The reactor 10 may further include thermal control means 18 (shown in Figure 5) for controlling the temperature of the biomass 16 to a temperature optimal for the operation of the microbes 10. Preferably, by means of mixing and thermal control means independent of the blocks, the conditions and mixing in each block are optimized for microbial function. The thermal control means 18 may be, for example, resistors mounted on the modules 52 of the subframe 46 15 shown in Figure 4, by means of which the structures of the subframe 46 and thereby the biomass 16 are heated. Heating is important for the first two blocks, but in the next block or blocks where methanogenesis takes place, the biomass may no longer need to be heated or may even be cooled without further compromising the biogas yield.

Cooling can be performed by means of heat exchangers included in the heat control means, which can, for example, preheat the biomass fed to the reactor. Gas boilers can also be used for heating, which heat the second heating of the reactor water circuit, which can preferably be controlled in three or more block-specific circuits.

To recover the product biogas, the reactor 10 includes recovery means 22 for collecting the biogas from inside the reaction space 14. The recovery means 22 may be a pipeline 54 of Figure 2 formed at the upper part of the body, i.e. at the upper end 13.1, by means of which the biogas formed is recovered in a storage tank 78 or the like.

20185183 PRH 27-02-2018

In the reactor 10 according to the invention, the mixing means 20 preferably include a reject collection and feed system 56 of Figure 2. The reject collection and feed system 56 is arranged on the side of the subframes 46 by means of a collection and feed system 56 5 for collecting reject from decomposable biomass 16. The collection and feeding system is not shown in Figure 4, but it should be understood that the subframes 46 include such means. In this context, reject means thick mass. The dry matter content of the thickener is 3-35 10%, preferably 15-25%. On the other hand, a mass with a dry matter content of 3 to 5% can in some contexts also be a thin mass. As shown in Figure 2, the collection and supply system 56 preferably includes a single thick pulp pump 57, by means of which the reject is transferred in the pipelines. The piping is provided with a valve system 88 which, under the control of the control system of the reactor 10, opens the valves 82 and 84 of the desired block 24 and closes the valves 82 and 84 of the other blocks 24. Preferably, rejecting the block before the block means feeding the reject to the feed connection before the reject also feeds up to the feed connection previously in relation to the feed connection preceding the discharge connection. Preferably, the reject is collected from the side of each sub-body, since the liquid in the reactor naturally generates a liquid pressure which aids in the transfer of the reject.

Since the collection of the reject is preferably part of the inoculation, care must be taken to ensure that the system for collecting and feeding the reject remains clean and in working order. For this purpose, the reject can occasionally be fed back through the discharge connection to the block 30 from which the reject is taken. This prevents the piping from clogging. The cleaning supply can be done, for example, twice a day, or when a blockage is detected on the pump or on the suction side of the pumps while the flow is monitored by automation. Here

20185183 PRH 27-02- 2018 automation automatically tries to open the blockage with counterflow.

The reject removed from the block can be led at a high pressure 5 along the piping 40 of Fig. 3 to a channel inside the hollow shafts 48 of the paddle mixers 36 and thereby to the paddles 45 of the paddle mixer 36. By high pressure is meant a pressure of 0.2 to 20 bar. The blades may include nozzles through which the reject is fed into the biomaterial 10 when blade mixers are used. Alternatively, instead of or in addition to the reject, liquid biomass can be fed as a feed via mixing means.

According to one embodiment, the reactor further comprises means 30 for reducing friction between the biomass and the biomass in the reaction space according to Figure 2, which means 30 for supplying thick matter and / or biogas from the walls 44 of the subframe 46 of Figure 4 into the subframe 46, e.g. The feed thickener and / or biogas 20 reduces the friction between the biomass 16 inside the subframe 46 and the module 52, which in turn reduces the need for force on the mixing means 20. The feed of thick matter and / or biogas can be point-directed, whereby when the biomass is fed into the thick matter and / or the biogas displaces the biomass, forming an opening therein which facilitates the advancement of the decomposable biomass in the reaction space. Preferably, the thickener has a biomass reject. While the feed mass and / or biogas fed reduces the friction between the biomass and the reactor body, it also inoculates the reactor. In addition, the liquid / gas mixture releases 30 gases bound to the solid and ensures that no methane is removed with the reject digestate.

In this context, it should be understood that the mixing means, for example paddle mixers, act not only as a mixture but also as a main plug-pushing element for the biomass in addition to gravity. According to one embodiment, the inner surface of the body can be coated, for example, with a coating corresponding to a Teflon coating, which reduces the friction between the biomaterial and the body and prevents the biomaterial from adhering to the inner surface of the body.

Preferably, the reactor according to the invention comprises a considerable number of measuring sensors which monitor the conditions for each of the 10 blocks in real time. The quantities to be measured are at least the pH and temperature in each block and the general gas production of the reactor. On the basis of these, separate control variables are formed for each of the mixing means, the heat control means and the reject feed on a block-by-block basis. Preferably, on the same basis, a control variable is also formed for the equipment to reduce friction. The amount of organic matter in the biomass can also be the object of measurement.

20185183 PRH 27-02-2018

In the process according to the invention, the reaction space is largely filled with liquid and biomass, so that the new raw material fed to the reaction space, i.e. the biomass to be decomposed, is fed below the liquid surface. This ensures that no air enters the reaction space with the biomass involved, which would destroy the microbial population performing the anaerobic digestion. Although the liquid surface and biomass are not illustrated in Figure 2 for clarity, it should be understood that the reaction space 14 is almost full of biomass up to the ceiling and the liquid surface extends about 20 to 200 cm from the upper end 13.1 of the reactor body 10, i.e. the end to which the biomass is fed. The removal of digestate in the reactor is controlled so that the height of the liquid surface always remains at the required level. The microbial strain itself can be transferred to the reaction space in connection with the start-up of the reactor, for example from another reactor. The biomass to be fed may be biodegradable biomass from communities, agriculture or industry, such as animal manure, biowaste from households, restaurants, trade or the food industry, sewage sludge, plant biomass or similar, but not lignin-rich material such as wood pulp without lignite.

Preferably, the dry matter content of the pulp in the reaction space in dry matter percentages can be between 10 and 35, but this drier material is difficult to mix. The dry matter content decreases towards the end of the reactor, where decomposition is prolonged. Biomass can be fed to the reactions, for example by means of a screw feeder. The feed can take place, for example, every hour around the clock, depending on the amount of organic matter and biodegradability of the biomass used as raw material.

20185183 PRH 27-02-2018

In the method according to the invention, according to Figure 2, the biomass 16 can be inoculated in four different ways; rotating the mixing means 20, feeding the reject by means of the reject collecting and feeding system 56 through the mixing means 20, feeding thick and / or biogas from the edges of the reactor body 10 20 by means of reducing friction, or mixing the reject into the feed prior to feeding to the reactor. While the anaerobic decomposition reactions are underway in the reaction space, gas production, pH, and temperature are constantly monitored, but inoculation and agitation are preferably sparse to save energy. As a result of these changes, reactor mixing, heating, biomass feed and reject feed are controlled by a reject collection and feed system. For example, if the pH is found to fall to too low a level or gas production to fall in the area of a block, the conditions can be influenced locally by enhancing agitation in that block and increasing or decreasing the feed of the reject to that block.

20185183 PRH 27-02-2018

The purpose of the mixing means 20 is to move the biomass 16 forward in the reaction space 14 and to mix the biomass 16 so that the microbes receive fresh food. If mixing is done too infrequently, a layer of degradation products is formed around the microbes, which can inhibit the activity of the microbes. Mixing can be used, for example, every hour for 15 minutes while feeding a reject to the block. Preferably, in addition to the mixing direction providing the lateral force, the mixing is also used in the direction opposite to the direction of the plug flow, whereby a different mixing is obtained. For example, when using a paddle mixer, parallel mixing always moves the biomass at a certain point in a certain direction of the paddle mixer. The change in the mixing direction brings in different mixing directions, which enhances the mixing of the biomass, the inoculation of the microbes and the supply of organic raw material to the microbes.

In general, the throughput time of the biomass in the reactor can be 11 to 50 days depending on the biomass used as feedstock.

Mixing and its direction are determined by the measured values, but backward mixing is generally performed shortly before the start of the biomass-forward mixing. The mixing power varies from block to block in the reaction mode. In the last block, the mixing is preferably the most efficient in order to separate the remaining biogas from the digest leaving the reaction space, which can be inside the solid digest in bubbles in so-called gas pockets. This is important to make biogas recovery efficient and to prevent methane from entering the atmosphere with the digestate, where it is a powerful greenhouse gas. Preferably, in the last block, the mixing lines are rotated in the opposite direction to the other blocks to enhance mixing. The digestate removed from the reactor can be led to separation, where liquid is separated from it. This liquid can be used, for example, to clean the reject collection and supply system.

20185183 PRH 27-02-2018

In the reaction state, the microbes cause anaerobic decomposition of biomass in the anaerobic state, which according to the prior art includes hydrolysis, acid fermentation (acidogenesis), acetic acid formation (acetogenesis) and methane formation (methanogenesis). Of these, the individual steps and the reactions they contain take place gradually and partially overlap in the reaction space. Preferably, the hydrolysis and acidogenesis take place mainly at the beginning of the reaction space, while the acetogenesis and methanogenesis take place mainly at the end of the reaction space. As a result of the reactions, biogas is produced as a final product from biomass, which contains about 50 to 75% by volume of methane (CH4) and the rest mainly carbon dioxide (CO2). In addition to these, the final product may contain small amounts of other gases and impurities such as 100 to 3000 ppm hydrogen sulfide (H2S). Depending on the end use of the biogas, the biogas obtained from the method can be purified from carbon dioxide, for example, if the biogas is used as a fuel in road transport. On the other hand, if biogas is used in combustion plants20 for energy and district heating production, it can be used as such. As a result of the decomposition reactions, in the reaction space, 50 to 90% of the organic matter in the feed is converted into biogas and liquid. If necessary, the by-product digestion can be dried or further treated in other ways, for example, and utilized, for example, in fertilizer use or as a soil improver.

The size of the reactor according to the invention can vary considerably depending on the intended use. The size of the reactor can be, for example, 30 2mx2mx4m (p, l, k), but it can also be scaled to, for example, 12 m x 12 m x 50 m or larger. In connection with large reactor sizes, several feeders can be used to achieve feed uniformity. Here 12 m means

20185183 PRH 27-02- 2018 reactor length and width and 50 m reactor height in the direction of plug flow.

The control of the reactor according to the invention can be implemented using, for example, a normal PC as the operating platform on which the reactor control program runs. There is a fieldbus for communication between the PC and the actuators, sensors and other control devices such as valves. The method according to the invention can be fully automated, whereby the program controls the operation of the reactor on the basis of preselected criteria in accordance with preselected rules.

Figure 5 shows a reactor according to an embodiment of the invention as a process diagram together with additional equipment associated with the reactor. In one embodiment, the process is started from a feed table, to which solid biomass is preferably fed in bales, which are torn by a bale ripper into a smaller shred. The feed table and bale ripper are not shown in the pictures. The feed from the bale tear drips into the feed hopper 25.2 and through it into the screw conveyor 25.1, which feeds the feed through the feed connection 71 to the reactor 10 at preset intervals, for example once an hour. A pipe crusher may be located in the feed connection 71, which further grinds the feed. In addition to solid biomass, 25 reactor liquid rejects can be fed to the feed connection 71 via line 75 to reduce friction. A liquid feed can also be fed to the reactor 10, for example fats, which can be stored in a tank 76. The liquid feed can be fed to the reactor through a thick mass pump 57 of the reject collection and feed system 56.

As shown in Figure 5, the reactor 10 may comprise four mechanical stirrers, which in this case may be paddle stirrers 36. The stirrers may also be in parallel, whereby the diameter of a single stirrer is smaller. For each paddle mixer

20185183 PRH 27-02-2018 preferably has its own motor 65 and a frequency converter, by means of which the rotational speed can be adjusted. The power of a single motor can be, for example, 4 kW and the rotational speed 6 revolutions per minute. The body 12 of the reactor 10 is divided into at least three blocks 24, i.e. a hydrolysis block, an acid fermentation block and a methanogenesis block. In each block 24 rejects are fed by means of a reject collecting and feeding system 56 in front of the block. As shown in Figure 5, the reject is removed from the block via the discharge connection 60 to the collection and supply system 56, preferably as a Salo pulp by means of a vacuum provided by the pulp pump 57.

For example, at the third paddle mixer 36 ', the reject is removed through the outlet connection 60' when the outlet valve 82 'is open. The reject passes through the thick pulp pump 57 and is fed through an open supply valve 84 'to the reject supply connection 15 62'. In this case, the reject feed connection 62 'is preferably located in the blades of the paddle mixer 36'. Reference numeral 62 generally refers to a supply connection, reference numeral 82 denotes an outlet valve, and reference numeral 84 denotes a supply valve.

In other words, preferably the microbial strain of each block is recycled within the block so that the microbial strain is taken out of the block as a reject and preferably fed back to the block via mixing means. In each block, the reject removal connection is spaced from the mixing means or the feed connection of the reject 25 from which the reject is fed back to the block. This distance varies according to the size of the reactor, but preferably the feed connection and the reject outlet are 0.2 to 0.6 times the length of the block, with the reject outlet as close as possible to the end of the block.

The distance allows the natural development of the microbial population within the block.

The decomposed biomass, i.e. the digestate, is removed from the end, i.e. the last block 24 of the reactor 10, by means of a pump 68. The pump is operated based on the measurement of the level meter of the reactor 10 when the preselected level is exceeded. The removed digestate is preferably led to a dry digestate storage, where the dry matter and liquid are separated by a matrix tube. The biogas generated in the reactor 5 can be recovered in the gas storage 78.

Preferably, in connection with the gas storage, there is also a condensate water well 81, in which condensed water condensing from 100% of the biogas in moisture is collected. A portion of the biogas can be used to heat the liquid heating circuit 77 of the reactor 10 with a gas boiler 74.

20185183 PRH 27-02-2018

According to one embodiment, the reactor 10 includes biogas recirculation means combined with recovery means 22 for recirculating the recovered biogas pressurized to the lower end of the reactor body 15 to mix the digestate and remove the biogas from the digestate. The biogas recirculation means may include, as shown in Figure 2, a flow passage for connecting the recovery means 22 to the lower end 13.2 of the reactor 10 body 12.2 for recirculating biogas and a pump 33 20 fitted to the flow passage to suck biogas from The body of the reactor according to the invention is preferably made of steel plate by welding, but the body can also be a material that can be 3D printed. Such materials can be, for example, concrete, fiber concrete or composite. The external support frame, on the other hand, is preferably made of steel, but in principle the external support frame can also be 3D printed on concrete or fiber concrete. The reactor according to the invention with a vertical body is also advantageous from the point of view of 3D printing, because the transition distances of the print head of the 3D printer are smaller than in a horizontal reactor.

The reactors according to the invention can easily be installed side by side without a gap, whereby it is easy to increase the capacity of the unit. The small bottom surface area of the reactor according to the invention allows such an adjacent arrangement.

In the reactor 10 according to the invention, the feed means 25 and the solids removal means 27 may be on the same side, whereby the building for the feed means 25 of the reactor 10 and the building for the solids removal means 27 may be the same building 99. Biomass can be introduced into the building, for example by truck 98.

Claims (15)

A reactor for the production of biogas from biomass by anaerobic digestion, comprising 5 - a body (12) comprising two ends (13), namely an upper end (13.1) and a lower end (13.2) delimiting inside a reaction space (14) for biomass (16), which body (12) is channel-shaped for plug flow of biomass (16), and the body (12) comprising at least three successive blocks (24) with microbial strains, 10 - supply means (25) arranged at the upper end (13.1) of the body (12) for feeding biomass inside the body (12), - mixing means (20) for mixing the biomass (16) and feeding the microbes into the biomass (16) at least partially inside the body (12), - recovery means (22) for recovering the generated biogas when the microbes consume the organic material of the biomass (16), and - solids removal means (27) fitted to the lower end (13.2) of the body (12) for removing solids, 20 characterized in that said body (12) is arranged to be vertical as the biomass (16) moves in the reactor (10) in the vertical direction, and the reactor (10) further comprises - an outer support frame (50) arranged outside the body (12) to support the body (12) from the outside of the body (12) 25 against the hydrostatic pressure generated, - a bottom cone (17) comprising a wider upper end (90) and a narrower lower end (92) connected to the lower end (13.2) of the body (12) for collecting solids, said solids removal means (27) being arranged at the lower end (92) of the bottom cone (17) to remove solids . Reactor according to claim 1, characterized in that the mixing means (20) comprise a reject collection and feeding system (56) for collecting the reject from the blocks (24) and feeding it to at least three blocks (24) as a thick mass. Reactor according to Claim 2, characterized in that the reject collection and supply system (56) comprises a thick pulp pump (57) for feeding the reject at a dry matter content of 3 to 35%, preferably 10 to 20%. Reactor according to Claim 2 or 3, characterized in that the reactor (10) comprises means (30) for feeding thick matter and / or biogas from the walls (44) of the reaction space (14) to facilitate the flow of biomass (16). Reactor according to any one of claims 2 to 4, characterized in that said thick pulp pump (57) is a hydraulically operated piston pump. Reactor according to any one of claims 1 to 5, characterized in that said mixing means (20) are implemented 20 reactors (10) with axes transverse to the vertical (12) for mixing the biomass (16) on a block-by-block basis. 20185183 PRH 27-02-2018 Reactor according to one of Claims 1 to 6, characterized in that there are at least 3, preferably 3, blocks (24). 25 - 6. Reactor according to any one of claims 1 to 10, characterized in that said recovery means (22) are arranged in connection with the upper end (13.1) of the body (12) of the reactor (10). Reactor according to one of Claims 1 to 8, characterized in that the external support frame (50) is a steel truss structure (94). 20185183 PRH 27-02-2018 Reactor according to one of Claims 1 to 9, characterized in that the body (12) of the reactor (10) is made of a steel plate 4 to 20 mm thick. 5 Reactor according to one of Claims 1 to 9, characterized in that the body (12) of the reactor (10) is a 3D-molded structure made of fiber-reinforced concrete with a thickness of 100 to 400 mm. Reactor according to one of Claims 1 to 11, characterized in that the reactor (10) comprises biogas recirculation means combined with recovery means (22) for recirculating the recovered biogas under pressure to the lower end of the reactor body for mixing the digestate and separating the biogas from the digestate. 15 Reactor according to claim 12, characterized in that the biogas recirculation means comprise a flow channel for connecting the recovery means (22) to the lower end of the reactor (10) body (12) for recirculating the biogas and a pump (33) 20 arranged in a flow channel for sucking biogas from the recovery means and for pressurizing the recyclable biogas before the biogas is fed into the reactor (10) body (12) to the lower end (13.2) of the body (12). 25 Reactor according to one of Claims 1 to 13, characterized in that the height of the body (12) of the reactor (10) is 2 to 4 times the width or length of the reactor (10). A reactor according to any one of claims 1 to 14, 30 characterized in that the feed means (25) of the reactor (10) are arranged in connection with the body (12) so that the feed means (25) feed biomass below the liquid surface inside the body (12) of the reactor (10).