FI81774C - Reactor designed to generate biogas - Google Patents

Description

81774 1 Reactor for the production of biogas

The invention relates to a reactor for the production of biogas.

The invention relates to the efficiency of the utilization of waste material used in the production of biogas. The possibilities for utilizing the residual sludge generated in the digestion process of the waste material are numerous, and the invention seeks to provide an apparatus for producing biogas in which part of the digested organic matter can be utilized, e.g. as a soil improver.

Digestion is a method in which organic matter is broken down by bacteria, e.g.

15 methane bacteria, resulting in biogas that can be further burned in boiler plants or whose energy can be otherwise utilized.

Digestion is a commonly used method e.g. in the treatment of municipal sewage-20 roads. It improves the hygiene of the sludge and. . drying properties, while the process produces at least its own; the amount of digestion gas required for heating. In general, not enough results have been achieved in terms of energy economy. However, it is well known that increasing the gas yield would make the method also profitable in this sense.

Prior art means of increasing biogas production include elevated process temperature, efficient mixing of reactors, division of the process into compartments suitable for different microbial groups, control of acidity, addition of various organic or inorganic nutrients, and removal of certain heavy metals or sulfide ions.

It is also known that methane bacteria require highly reduced conditions to function and it is known that oxygen - released from the atmosphere or through chemical reactions - is toxic to the vital functions of methane bacteria at very low concentrations. Therefore, the aim has been to prevent 2 81774 l of oxygen from entering the sludge mass into the biogas process itself as effectively as possible.

The object of the invention is therefore also to provide a device which is economically advantageous in total. It is also an object of the invention to provide an apparatus which makes it possible to utilize the various fractions of the reactor. It is also an object of the invention to provide an apparatus for producing biogas in which it has been possible to increase the efficiency of gas production.

According to the invention, a biogas reactor is provided which comprises a vertical axis of rotation of the digestible waste material. According to the invention, the reactor has several outlets for separating different fractions from the digested waste material. According to the invention, a biogas reactor is also formed, in which a part of the biogas is led above the sludge inlet pipe of the reactor 15 and the so-called flotation to separate the impurities in the slurry from the surface of the sludge mass itself, whereby a fraction free of impurity particles can be separated from the center of the vessel, which can be used e.g. in landscaping.

The biogas reactor according to the invention is mainly characterized in that the reactor for producing biogas comprises a rotatable gas flotation element arranged in the lower part of the reactor above the inlet of the waste feed pipe and in that the gravity separation is preferably below

According to the invention, the reactor comprises at least one waste outlet in the central part of the reactor. If desired, waste material is led through said outlet to the outlet pipe, in which case said passage of waste material 30 is preferably effected by means of gravity. After the outlet, a valve is provided, the opening and closing of which regulates the removal of the fraction in question from the reactor. According to the invention, the reactor comprises an outlet for the fraction deposited on the top of the sludge mass arranged close to the upper surface of the slurry. Again, a valve is arranged in connection with said outlet 35, whereby by opening the valve, the fraction in question can be led out of the reactor. Preferably there is a waste mass

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3 81774 Ί vanes or the like arranged at the top of the top surface to transfer the contaminants deposited on the top of the waste mass out of the reactor vessel.

The invention will now be described with reference to some preferred embodiments of the invention shown in the figures of the accompanying drawings, to which, however, the invention is not intended to be exclusively limited.

Figure 1 shows a biogas reactor according to the invention in a cross-sectional schematic view and a schematic representation.

Figure 2 shows another preferred embodiment of a biogas reactor according to the invention in a cross-sectional view and a schematic representation, respectively.

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Figure 3 shows a third preferred embodiment of a biogas reactor according to the invention, respectively in a side view and in a cross-sectional view.

Figure 4 shows a fourth preferred embodiment of the invention.

As shown in Figure 1, the biogas reactor comprises a feed pipe 1, through which the digestible organic matter is introduced into the reactor 3 and its lower part. At the top of the reactor 3 there is a gas pipe 4 for conducting biogas 25 out of the reactor. Through the said pipe 4, the biogas is passed on to a burner, for example, or is otherwise recovered. A sedimentation unit 8 is arranged in the lower part of the reactor 3, comprising a gas flotation member 8b, a gas pipeline 8c and mixing elements 8d and 8d '. A side branch 4b branches from the main branch 4a of the gas pipe 4 and the gas pumping device 5 30 conveys part of the biogas along the branch pipe 4b to a gas line 8c extending below the reactor 3 to the reactor 3, which further leads to the so-called biogas. a gas flotation member 8b comprising a plurality of nozzle openings 8b 'through which the gas is discharged to the digester *. organic matter. The gravitational separation is adapted to take place below the flotation member 8b by means of preferably rotating vanes 8d and 8d 'or other similar parts moving in the part in question.

4 81774 1 The gas line 8c is rotated by a mixing motor 6. The gas flotation member 8b attached to the gas line 8c rotates inside the reactor 3 and through the nozzle openings 8b 'the biogas is bubbled into the organic digestible material. In this case, some of the impurities in the digestible substance in question, e.g. plastic parts, rise with the bubbles on the surface of the slurry, from which they can be separately separated.

Connected to the gas line 8c, which is rotated by the mixing motor 6, the gas flotation member 8b of the sedimentation unit 8 and the mixing members 10dd and 8d 'are connected.

The gas flotation member 8b is located substantially above the inlet opening 1a of the supply pipe 1. The bottom part 3a of the reactor 3 is preferably conical and the wall surfaces 3ax of said conical part are substantially parallel to the lower mixing fins 8d '. Heavy particles, such as glass shards and the like, settle in the settling section 7, and by means of the sludge removal pump 7b of the settling section 7, these impurities can be further removed from the reactor 3 via the outlet 12 '. Above the nozzle openings 8b 'of the flotation member 8b in the reactor 3 there is an outlet 12 "through which the digested waste from the reactor 3 can be discharged for further removal and utilization. contaminants fraction. The outlets 12 "and 12" 'of the upper fractions are connected to the channel 13a and the outlet 25 12' of the bottom fraction is connected to the channel 13b, which channels are further connected to a common outlet pipe 13c.

A valve 14 "is arranged in the outlet channel after the outlet opening 12" of the middle fraction and a valve 14 "'is arranged in the associated channel part after the outlet opening 12"' of the upper fraction. By opening these valves alternately, the desired fraction can be removed along the channel 13a and further along the channel 13c, the decomposed organic matter preferably leaving the reactor 3 by gravity.

Figure 2 shows another preferred embodiment of the invention. This embodiment differs from the embodiment of Figure 1 in that the reactor 3 comprises a vertical shaft of at least two parts.

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In the embodiment, the shaft comprises a first shaft portion 15a and a second shaft portion 15b. The shaft sections are connected to each other at their ends by an end-bearing 16. At least the lowest of the shafts is such that biogas can be introduced into the gas flotation element 8b as shown in Fig. 1. Preferably, the shaft 15a is a hollow tube. The upper shaft 15b is rotated by a motor 17 and the lower shaft by a motor 6. The upper shaft comprises guide vanes 10a and 10b which mix the sludge. The motors can rotate the shafts 15a and 15b in different directions, thus enhancing the so-called sedimentaatiotapahtumaa. The ends of the vanes 10a and 10b are preferably arranged Ίq in a plane where they pass past the outlets 12 "and 12 '" and thus prevent the outlets from clogging. The same motor can rotate both shafts 15a and 15b and also in different directions via the gearbox. Valve 14 "is adapted to open and close the outlet 12" and valve 14 '"is adapted to open and close the uppermost outlet 15 12'" ·

Figure 3 shows a third preferred embodiment of the invention, in which a separate motor-rotatable vane 19 is arranged at the very top of the vessel. The motor 18 is arranged at the top of the reactor 3 on the upper surface of the reactor jacket and is adapted to rotate the vane shaft 19 '. In the plane of the wing 19 there is an outlet opening 20, through which impurities accumulated on the surface with the flotation, e.g. plastics and other light structural parts, are removed.

The central slurry section A of the reactor 3 has two separate outlets 21 and 22, as shown in the figure. In addition, the lower part of the reactor 3 has an outlet 23 for heavy settling particles 23. Thus, four different fractions can be taken out of the reactor 3 in the reactor of the figure. The lowest fraction comprising the heavy impurities 3Q accumulated in the settling section 7 is removed through the outlet 23. The sludge in the different digestion stages can be removed through the outlets 21 and 22 and the impurities accumulated on the surface of the sludge section can be separated from the top outlet - 20. A valve 26 is arranged in connection with the outlet opening 22 and a valve 25 is arranged in connection with the outlet opening 21. A valve 24 is arranged in connection with the outlet opening 20, respectively, and a valve 28 is connected to the outlet opening 23 in the channel 13b. The channel 13a further comprises a valve 27 at its lower part.

6 81 774 1 Figure 4 shows a fourth preferred embodiment of the invention from the side and in a schematic representation. In the embodiment of the figure, the reactor 3 comprises a first basic conical downwardly tapering wall portion 30 and a second conical wall portion 31, between the conical portions 5 of which there is a portion 3b comprising a straight cylindrical jacket surface. Below the first conical section 30 there is a lower part of the biogas reactor tank 3 enclosed by a cylindrical jacket surface 29, which contains mixing elements or vanes 8d rotated by a flotation member 8b and a shaft 8c. The flotation member 8b with the biogas directional openings 8b 'is located substantially in the vicinity of the junction of the parts 29 and 30 of the tank 3.

The upper part of the container 3 comprises, above the second conical part 31, an upper part 32 with a straight cylindrical jacket surface, which encloses the shaft 33 and associated motor-driven wings 34 and 35, the ends of which are preferably adapted to pass through fractions leading from the container part 32. past the outlets 37 and 38, whereby the vanes prevent the outlets 37 and 38 from clogging. Valves 39 and 40 are arranged in connection with the channels of the fraction outlets 37 and 38, by opening and closing of which the desired fraction can be removed along the channel 2Q 13a.

Below the part 29, the tank 3 comprises a settling part 7 and an outlet channel 13b, through which the fraction is removed by pressure by means of a cylinder 7b and another actuator.

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The circulation of biogas along channels 4 and 4b may be similar to that in the previous embodiments. Thus, some of the biogas is introduced into the flotation member 8b along the channel 4b.

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Claims (7)

A biogas production reactor comprising a vertical reactor (3), a feedstock (1) for organic matter to be digested, and an outlet pipe (4) for the biogas, at least three outlet openings (7.12 ", 12 '') for fractions of organic matter to be digested or particles resulting therefrom and mixing devices within the reactor (3) for the organic substance to be digested, characterized in that the reactor for the production of biogas comprises a rotatable gas rotation means (8b) arranged in the lower part of the reactor vessel (3) above the entrance opening (1a) of the feed tube (1) for the residual blank and the gravitational separation is arranged below the flotation part (8b), advantageously in the lower part, while mixing means (8d) promote separation. 15 1 Patent Claim 9 81774 Reactor according to claim 1, characterized in that the reactor comprises an axis in the lower part of the reaction vessel (3) which causes the gas flotation means (8b) to rotate, via which axis it is also advantageously introduced for biogas via the gas flotation means, whereby the biogas is distributed. via nozzle openings (8b ') by causing the flotation: the organ (8b) to move in the organic substance to be digested. 3. A reactor according to claim 1 or 2 for the production of biogas, characterized in that the reactor (3) comprises at least one outlet opening (12 ") for residual material in the middle part (A) of the reactor (3), whereby via the outlet opening (12 "), if necessary, a residual lead into the outlet tube (13a, 13c), advantageously by gravity, by opening and closing a valve (14") arranged after the outlet opening (12 "). 30 4. Reactor according to any preceding claim for the production of biogas, characterized in that the reactor comprises one. outlet port (12 "', 20.37) for the fraction stored in the upper. ···, the portion of the residual mass which aperture is provided in contact with the upper surface of the residue and a valve (14"', 24, 39) arranged in connection with this opening, whereby by opening the valve (14 ", 24,39), the relevant fraction can be led out of the reactor (3). 5. A reactor according to any of the above claims for the production of biogas, characterized in that the plant comprises a manifold (4b) which connects to the outlet pipe (4) for the biogas, through which manifold is advantageously fed a portion of the biogas pumped by the pump device. (5) to the gas flotation means (8b). 6. A reactor according to claim 1 for the production of biogas, characterized in that the reactor comprises a vertical shaft comprising at least two parts (15a, 15b), the ends of which are arranged against each other and which shafts can be rotated independently of each other. 7. Reactor according to any of the preceding claims for the production of biogas, characterized in that the reactor comprises a transverse rudder (10a, 19,34) which sweeps over the upper part of the residual mass, which rudder is arranged to move contaminants that have been cooled and stored. in the upper part of the sludge, via the outlet opening 20 (2 ", 20.37) out of the reactor (3).