RU2536988C2 - Reactor of anaerobic digestion of biomass - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to bio-energy and can be used as a universal digestion tank for processing of manure of animals, poultry, domestic and agricultural waste into methane and organic fertiliser. The reactor of anaerobic digestion of biomass comprises a housing 1 in the form of a sealed container, comprising four sections: preparatory (acidic) 2, neutral 3, alkali 4 and of methane digestion 5, separated by vertical partitions 6, 7, 8. The reactor is additionally equipped with a diaphragm electrolytic cell 12, one output 18 of which with the analyte solution is connected to the acid fermentation section 2, and its other output 21 with the catholyte solution is connected to the sections of neutral 3 and alkaline fermentation 4. In the reactor housing 1 along its length the additional fixing units 11 of vertical partitions 6, 7, 8 are made, made with the ability of replacement with the change in the volumes of sections of fermentation.

EFFECT: invention enables to increase efficiency of the reactor of anaerobic digestion of biomass.

6 cl, 1 dwg

Description

The present invention relates to bioenergy and can be used as a universal digester for processing into methane and organic fertilizer manure of animals, birds, household and other agricultural waste.

Devices of a similar purpose are known [1, 2, 3, 4], for example, “Method for the preparation of organic fertilizers” according to copyright certificate No. 433114, “Metantenk” according to copyright certificate No. 1353753, “Methane bio-cultivator” according to patent No. 2093567, “Complex for processing and waste treatment "according to patent No. 2162380 and others.

These devices comprise a matanette case divided into sections, biomass heaters, feed and removal systems, a sludge mixing system in digesters, and a gas removal system.

The devices listed above have different structural design, but are not universal and are intended, as a rule, for processing one kind of waste.

For example, bird droppings and distilled bard are not processed into biogas in a conventional fermentation reactor, and it is necessary to install an additional hydrolysis reactor in it to control the level of acidity, otherwise the bacteria may die due to the high content of acids or alkalis. Acid-base balance management also allows increasing methane yield.

Similar innovations in the listed analogues are absent.

The closest technical solution (prototype) is the "Method of anaerobic processing of organic waste and installation for its implementation" [5] according to the patent of the Russian Federation No. 2315721.

This installation contains an anaerobic bioreactor with a biomass heater, a feed system, a biogas removal system, a liquid organic fertilizer removal system, a process control system, and the bioreactor is divided by partitions into four fermentation sections, a feed preparation system with a grinding, heating and mixing device is introduced fermented sludge, as well as a device for intensive mixing of biomass inside the anaerobic reactor.

The disadvantage of this installation is its complexity, which reduces the reliability of the installation and increases the cost. This device does not provide for a mutual change in the volume of fermentation sections depending on the types of raw materials, which reduces its effectiveness, including in connection with the transition from one fermentation mode to another. In [6] on page 6, the appropriate reactor volume is indicated depending on the amount of manure obtained from cattle, pigs, horses or chickens.

In addition, the opinion [7] on p.21 also confirms the opinion that "... due to the variety of recyclable waste and other factors, it is currently impossible to confine ourselves to one or more designs of digesters ...".

Another disadvantage of the prototype is the inability to control the balance of the acid-alkali in the corresponding sections of the digester, which does not allow optimal influence on the biogas output.

Another disadvantage of the prototype is the use of pumps for intensive mixing of biomass in order to equalize the temperature in the bioreactor. In [7], p.21, it was stated: “... The maximum methane emission was found at a very low mixing intensity, providing only homogenization of the fermenting liquid ... Thus, the main task of mixing is to prevent material sedimentation, destruction of the upper crust, desorption of biogas and ensuring cultural homogeneity liquids according to physicochemical parameters; "the direct effect of mixing on the intensity of methane fermentation through the mechanisms of mass transfer was not found in our experiments." Other studies also confirm that intensive mixing of biomass destroys the already existing clusters of methane bacteria and worsens their adhesion to the inner surfaces of the digester.

The objective of the present invention is to remedy these disadvantages.

The technical result of the proposed solution is as follows:

- increasing the efficiency of the reactor through the use of a diaphragm electrochemical electrolyzer and controlling the acid-base balance by accelerating the creation of acid, neutral, alkaline or methane fermentation optimal for them in the appropriate sections. In addition, an increase in reactor efficiency is achieved by creating the optimal ratio of the volumes of the reactor sections by reinstalling the partitions inside the digester for specific types of raw materials and fermentation conditions. For example, OJSC “Agromed” recommends when using cattle manure, the ratio of the volumes of the sections of hydrolysis - acid fermentation - methane formation as 1: 2: 4. For another type of feed, the volume ratio of the chambers will change;

- increase in efficiency due to the implementation of partitions of flexible conductive materials connected to a low-voltage current source, which allows you to create the optimum temperature on their surface for adhesion and propagation of methane bacteria, as well as warm the layer of fermentable biomass along the height of the reactor without increasing the intensity of the mixers;

- increasing the efficiency of the reactor by placing suspended fine-mesh nets of fibrous material inside sections that immobilize the class of bacteria corresponding to this section on their surfaces;

- increasing the efficiency of the reactor due to the implementation of the fine mesh of conductive graphite felt connected to a power source, which allows additional heating of the biomass and improve the immobilization of bacteria on their surface;

- increasing the efficiency of the reactor by introducing into the preparatory (acidic) section of the air aerator a liquid and introducing part of the liquid separated from the solid sediment from the methane fermentation section;

- increasing the efficiency of the reactor through the use of an additional heat exchanger, two heat exchanging surfaces of which are connected to the outlet of the solid sediment and to the output of biogas with stored heat, and a third heat exchange surface to the input of additional water from the main, which saves energy by heating it to the required temperature .

As a result of a search by the sources of patent and scientific and technical information, we did not find the totality of features characterizing the described “Anaerobic Biomass Processing Reactor”.

Thus, the proposed technical solution meets the criterion of "new".

Based on a comparative analysis of the proposed solution with the prior art, it can be argued that between the set of distinctive features, their functions and the task achieved, the proposed technical solution does not follow explicitly from the prior art and, in our opinion, meets the eligibility criterion of “inventive step”.

The proposed technical solution may find application as a universal digester for fermentation of various biomass.

The drawing in section shows the design of the Anaerobic Biomass Processing Reactor.

The reactor contains a thermostatic housing 1 with sections 2, 3, 4, 5, respectively: preparatory (acidic), neutral, alkaline and methane fermentation, separated by partitions 6, 7, 8, and the structurally rigid partition 6 is insulated, for example, with graphite felt [8, 9] so that the lower temperature of section 2 when loading it with a new portion of biomass does not destabilize the steady-state optimum temperature in the neighboring section 3. Partitions 7 and 8 can also be made in the form of rigid planes coated with conductive carbon woven fabric, or can be made of flexible conductive carbon fabric [8, 9, 11] of type VVKN-46-110 according to TU 3497-005-11590737 or hard planes are covered with carbon felt according to TU 3497-029-11590373-04.

If the partitions 7 and 8 are made of elastic fabric, then the float 9 and the load 10 are held in the vertical plane of the partitions. The change in the volume of the sections is achieved by rearranging the partitions to new electrically isolated assemblies 11 for their fastening.

The electrochemical electrolyzer 12 has a capacitance 13 with a porous diaphragm and electrodes 14 and 15 connected respectively to the positive and negative poles of the power source. Water enters the electrolyzer inlets through valves 16, 17, and from the outlet 18, hydrogen ions (anolyte) are supplied through valve 19 to section 2 (acidic water), and their excess through valve 20 is discharged to the atmosphere. From another outlet 21 of hydrolyzer 12, hydroxyl group ions (catholyte - alkaline water) are supplied through valves 22 and 23 to other sections of the reactor, while the concentration of hydrogen ions is continuously monitored by pH sensors (not shown in the drawing). In the work [10] on page 9 it is indicated that “... As a rule, bacteria are more active at a pH of 6.4–7.2. At 8 <pH <6, the growth rate of bacteria decreases rapidly. " According to the most controlled biogas output rate, the fermentation process is divided into phases of acidic, regression of acidic (neutral) and alkaline fermentation with an optimal pH for each section.

Excess alkaline water is removed through valve 24. An aerator 25 is installed in the hydrolysis section, compressed air is supplied to its inlet 26, and vertical fine-mesh nets 27 of fibrous material with a large developed surface are introduced into each section.

If the grids are made not of fiberglass material, but of electrically conductive fabric [11], then they are mounted on insulators, and their ends, as well as the ends of the conductive partitions 7 and 8, are connected to a low-voltage power supply 28.

Water from the mains is fed through a heat exchanger 29 to an electrolysis cell 12 and through a valve 30 to an inlet of a reactor, moreover, biogas from one outlet 31 of the reactor and 32 from its other outlet, fermented biomass having accumulated thermal energy pass through different heat-exchanging surfaces of the heat exchanger, heating water from the highway. This saves energy on heating and maintaining the optimum temperature in the reactor.

Biogas is transferred further for cleaning and to a gas tank (not shown in the drawing). The fermented biomass enters the liquid fertilizer removal system to a separator 33, where solid sediment is separated, and the liquid phase, which still retains heat, is pumped through valves 35 and 36 to different sections of the reactor through a pump 34.

The reactor also contains a feed system in the form of a press extruder 37 for dispersing the incoming feed, a compressor 38 or a compressed air source, pumps 39, electric mixers 40 in each section, a main biomass heating system, for example, according to the “warm floor” scheme 41 pH sensors of the biogas output intensity level. Sensors for monitoring reactor parameters and its automatic control system are not shown.

The anaerobic biomass processing reactor operates as follows.

Depending on the type of processed raw materials, the required volume of sections 3, 4, 5 is established in the reactor vessel 1. For this, the partitions 7 and 8 are reinstalled on new electrically isolated nodes 11 of their fastening. If the partitions 7 and 8 are made of elastic material, then the partition 7, fixed at the bottom in the vertical plane, is held by the float 9, and the partition 8, fixed at the top, is stretched and installed in the vertical plane by the load 10.

The biomass is dispersed in a press extruder 37 and enters section 2, which also receives water from the line through valve 30, and through valve 19 sour water (anolyte) enters from the outlet 18 of the cell and part of the fermented water through valve 36 from the exit of the reactor.

At the initial start-up of the reactor, as well as at reduced temperatures of the incoming air, the main heating of the biomass is carried out by the heating system 41, and additional heating in order to accurately and evenly maintain the temperature is provided by the conductive surfaces of the partitions 7, 8 and grids 27 with a developed fibrous surface.

To activate the activity of acid bacteria, section 2 is supplied with compressed air in the form of many small pop-up bubbles from the compressor 38 through the aerator 25 [12, 13]. Aerators are widely used in flotation technology.

The biomass solution prepared in section 2 is pumped into the neutral fermentation section 3 by a pump 39. Catholyte (alkaline water) enters the same section from the outlet 21 of the electrolyzer 12 through the valve 22, and part of the fermented water from the outlet of the reactor through the valve 35.

When the optimal pH in sections 2 and 3 is selected according to the readings of the sensors, excess acidic water is drained through valve 20, and excess alkaline water is drained through valve 24.

Through the valve 35, the main part of the liquid separated by the separator 33 enters, which allows you to save thermal energy and useful methane bacteria in circulation.

The addition of cold biomass and water from the main affects the temperature of the solution in section 2, therefore, to reduce its effect on the temperature of the solution of section 3, the partition 6 between these sections is insulated.

Methane bacteria in section 3 accumulate on the developed surfaces of the nets 27 and partitions 7. During the operation of the mixers 40, oscillatory movements of nets and partitions occur in each section, which increases the contact time with free-floating methane bacteria and accelerates the formation of clusters of bacteria deposited on their surfaces.

At the next additional loading of the solution from section 2 to section 3, the last one moves a similar volume of the solution through the top and lateral leaks of the partition 7 into the alkaline fermentation section 4. According to the readings of the pH sensors and the methane output sensors, the necessary amount of alkaline water from the outlet 21 of the electrolysis cell 12 can also be added to the section 23 through the valve 23 to enhance methane fermentation.

The daily change in the temperature of the solution in metatens, which ensures the optimal reproduction of methane bacteria, should be [7, 10] in the range 1 ... 3 ° C.

In the proposed reactor, more accurate maintenance of the temperature of the solution is achieved by heating the conductive surfaces of the partitions 7, 8 and grids 27 from a low-voltage power source 28.

From section 4, the solution enters between the bottom of the housing and the lower end of the partition 8 (load 10), as well as through the lateral leaks of the partition into section 5 for final fermentation.

The connection at the outlet of the reactor of the heat exchanger 29 makes it possible to use the heat of the generated biogas and the heat of the fermented solution to heat the water from the main, which also saves part of the energy resources.

By ensuring optimal control of the pH and temperature of the solution in each section of the reactor, maximum plant productivity can be achieved.

The proposed reactor will find wide application as a universal digester for anaerobic processing of biomass with various properties.

INFORMATION SOURCES

1. USSR copyright certificate No. 433114, IPC C05F 3/00. A method of preparing organic fertilizers. V.P. Losyakov. - No. 1835755; declared 12.10.72, publ. 06/25/74. (analogue).

2. USSR author's certificate No. 1353753, IPC C02F 11/04. Metantenk. A.A. Kovalev and V.P. Losyakov - No. 4036561; declared 03/12/86, publ. 11.23.87 (analogue).

3. Patent No. 2093567 Russian Federation. IPC S12M 1/107. Methane bio-cultivator. IN AND. Tumchenok. - No. 95101288; declared 01/30/95, publ. 10.20.97 (analogue).

4. Patent No. 2162380 Russian Federation, IPC B09B 3/00, A61L 11/00, C05F 9/00, C05F 9/04. Complex for the processing and disposal of waste. R.F. Chizh, A.N. Chumakov, V.V. Degtyarev - No. 99115398; declared 07/21/99, publ. 01/27/2001 (analog).

5. Patent No. 2315721 Russian Federation, IPC C02F 3/28, C02F 11/04. The method of anaerobic processing of organic waste and installation for its implementation. V.V. Mokhov, E.V. Fomicheva. - No. 2006110378; declared 04.03.2006, publ. 01/27/2008 (prototype).

6. Construction of biogas plants. Quick start guide. United Nations Development Program. UNDP, Bishkek, 2006, p. 27.

7. W.E. Viestour, A.M. Kuznetsov, V.V. Savenkov. Fermentation systems. - Riga: Zinatne, 1986, 174 p.

8. Production of FSUE SPC “Carbon”, 129090, Moscow, Protopopovsky per., 9.

9. Carbon fabrics of RUE SPO Khimvolokno. 247400, Svetlogorsk, st. Zavodskaya 5 [Electronic resource] www.sohim.open.by.

10. Yanko V.G., Yanko Yu.G. Treatment of wastewater and sludge in meta-tanks, K., 1978, 120 pp.

11. The journal "Inventor and rationalizer", No. 6, 2001, p.13, "This multifaceted sorbent."

12. Copyright certificate No. 1139713 of the USSR, IPC C02F 3/20. N.F. Meshcheryakov. Device for aeration of a liquid.

13. Copyright certificate No. 1341167 of the USSR, IPC C02F 3/20. A.R. Gross Device for aeration of a liquid.

Claims (6)

1. An anaerobic biomass processing reactor containing a housing in the form of a hermetically sealed container, four sections: preparatory (acidic), neutral, alkaline and methane fermentation, separated by vertical partitions, the main biomass heater, feed system, biogas removal system, liquid removal system organic fertilizer, biomass mixing device, pH control sensors, solution level sensors in the housing, biogas formation intensity sensors, characterized in that the diaphragm is introduced an electrolytic cell, one outlet of which with the analyte solution is connected to the acid fermentation section, and its other outlet with the catholyte solution is connected to the neutral and alkaline fermentation sections, and additional fastening nodes of vertical partitions made with the possibility of rearrangement along the length are made along the length of the reactor vessel volumes of fermentation sections. 2. The anaerobic biomass processing reactor according to claim 1, characterized in that the partitions are made in the form of flexible conductive partitions connected to a power source for additional heating of the biomass and connected to maintain a vertical position with the float and with the load. 3. The anaerobic biomass processing reactor according to claim 1, characterized in that vertically arranged fine-mesh meshes of fibrous material with a developed surface are introduced into each section of the reactor. 4. The anaerobic biomass processing reactor according to claim 3, characterized in that the fine-mesh nets made of conductive graphite felt are connected to a power source for additional heating of the biomass and immobilization of bacteria on their surface. 5. The anaerobic biomass processing reactor according to claim 1, characterized in that an aerator connected to an air compressor is introduced into the acidic fermentation section. 6. The anaerobic biomass processing reactor according to claim 1, characterized in that a heat exchanger is connected to the output of the methane fermentation section, one heat exchange surface of which is connected to the biogas output, the other to the fermented biomass output, and the third heat exchange surface is connected to the water inlet from the reactor highways.