RU2549236C1 - Continuous underground generator of biogas - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: objective of the invention is to convert an operable periodical biogenerator plant with manual charging-discharging for production of low-pressure biogas into an industrial continuous plant for production of biogas of high pressure (5-6 MPa) by installation of a bioreactor in the ground at the depth of around 1200 m, which will provide for optimal temperature conditions of reactions of anaerobic conversion of biomass, will develop conditions for self-flowing charging of a bioreactor with biomass and gaslift discharging of biogas and residual biopulp. Standard drilling equipment and materials may be used for arrangement of continuous underground generators of biogas.

EFFECT: invention is ideally energy-saving and environmentally safe.

Description

The invention relates to the field of devices that are designed to produce biogas from wastewater of livestock farms and human life.

Similar technical inventions, in comparison with the proposed, are US patents US 4845034 and US 6962561.

Installation according to patent US 5845034 is designed to transfer the bioreactor underground for biochemical reactions, including for the production of biogas.

The main disadvantages of this installation are:

1) the need for the presence of a layer of rock salt at a certain depth underground to create a cavity for the bioreactor in it;

2) the choice of raw materials for the production of biomass of crushed coal, brown coal or peat, which require complex energy-intensive preliminary thermochemical treatment;

3) the need to grow strains of special salt-resistant methanogenic microorganisms and their mandatory introduction (seeding) into the biomass;

4) a small value of biogas pressure at the outlet of the installation, as evidenced by the presence of a fan at the outlet of it;

5) to ensure the operation of flow bioreactors requires a complex system of channels in the cavity of the bioreactor. The installation is energy-intensive, complicated in construction and operation.

US 6962561, as a bioreactor, proposes to use a layer of rocks, such as sandstones, with a thickness of at least 100 m, which are located at depths of 500 to 3000 m from the Earth’s surface, where rock temperatures are most favorable for anaerobic processing of biomass by methanogenic organisms.

The main disadvantages of this patent are:

1) the need for perforated rock in the place we need, this rock should be placed at the depth we need;

2) the layer of this rock should have a horizontal or slightly inclined placement in the Earth;

3) the cover of this layer should be impervious to gas and have a dome-like shape;

4) since the result of biochemical conversion of biomass will be biogas, bioil and biowater, the bioil will quickly silt the channels during filtration in the rock, as a result of which the bioreactor will stop working quite quickly;

5) the specified method for processing biomass is environmentally hazardous, especially when penetrating biomass or intermediate substances for processing biomass into aquifers;

6) the specified installation is energy-intensive, especially at the stage of pumping biomass into deep-seated rock layers, where the pressure is 10 ... 50 MPa;

7) the biomass processing process should be controlled, more often than not, regulated by a number of parameters.

The closest in technical essence to the proposed invention "is the installation according to the patent US 4388186. The description of the patent contains a description of the inclusion schemes of various devices for processing sludge and pulp in the installation for biogas from wastewater and systems that serve the installation, as well as the principles of construction and bioreactor work.

The main elements of the installation are: a biomass (sediment) preparation system, which includes a sedimentary tank of the first stage, aeration tank. sedimentary tank of the second stage, centrifugal sediment compactor, intermediate tank to complete the process of biomass splitting (installation option, pipelines not shown in the diagrams of Fig. 1 and 2, but necessary for operation of the installation, pumps, air processor for aeration tank, heating devices for heating biomass (sediment) to the required temperature (+ 35 ° С); a biopulp processing system, which includes a mixing tank with a mixer, dewatering machines) (squeezing press), dryer, granulator, kiln and tube rovody, biogas drainage system which includes a gas plenum, a compressor (not shown in Figures 1 and 2.), lines, including removing biogas consumers supply to susharke biopulp and a kiln; a multiple circulation bioreactor, which consists (in the variants of Figs. 3 and 4) with a cylindrical cup-shaped body (outer pipe) with external thermal insulation installed in the Earth in a well with a diameter of 5 m and a depth of 10 m, an inner pipe placed coaxially with the bioreactor body and intended for the downward movement of the biomass, the pump and the screw pump to ensure the circulation of biomass in the bioreactor, pipes for supplying biomass to the bioreactor, drainage of biogas from the top of the bioreactor and drainage of the biopulse.

The main disadvantages of the patent US 4388186:

1) the use of wastewater organics as biomass, but of “active bioil” (sludge), which significantly reduces the coefficient of beneficial use of biomass;

2) the installation is very energy-intensive, because even in a bioreactor a pump is used to ensure biomass circulation (see Fig. 3), or a pump and a screw pump (see Fig. 4);

3) it is recommended to place the bioreactor body in the ring not for using the internal heat of the Earth, but to reduce the heat loss of the bioreactor (see thermal calculations and the table in column 8 of the description);

4) the construction of wells in the Earth with a diameter of 5 m and a depth of 10 m, and even more so at a depth of 100 m, is a rather complicated, time-consuming and energy-consuming business; there are no drilling rigs with such a bit diameter yet;

5) the bioreactor in the installation is multiple-circulation, in this embodiment, the operation of the biogenerator installation should be periodic (proportional), otherwise complete biomass processing is not possible, the biogas pressure at the output of the biogenerator is small, as evidenced by the need to install a compressor at the exit of the bioreactor (see column 6, row 51 of the description);

6) the spontaneous biomass circulation system in the bioreactor, which is declared in the patent, especially in the entire biogenerator installation, is physically impossible (see Figs. 3 and 4).

In general, the bioreactor installation, which is considered to be inoperative, energy-intensive, low-tech, difficult in construction and operation.

The basis of the invention is the task of creating a high-tech, continuously operating, fairly simple to manufacture and operate a biogas generator, suitable for the complete utilization of municipal wastewater, wastewater of large livestock complexes with biogas (analogue of natural gas), bioil (organic fertilizer for rural household) and industrial water.

This problem is solved by placing the active zone of the bioreactor in the Earth, where the temperature of the rocks, due to the internal heat of the Earth, is optimal for the life of anaerobic mesophilic methanogenic microorganisms (+30 ... 35 ° C), using a self-flowing bioreactor, using a self-flowing loading system and unloading of the bioreactor due to the difference in the specific gravity and hydrostatic pressure of the biomass and biopulp (a mixture of biogas, biomass, bioil and water bubbles).

The figure shows a diagram of the proposed biogas generator, which includes: a tank with biomass (sewage of animal or human life) 1, a biomass supply pipe to bioreactor 2, a bioreactor body 3, an annulus 4, an end shoe 5 of a bioreactor body 3, an active zone bioreactor (height H ₃ ) 6, heat flow 7 from the rocks to the active zone b of the bioreactor body 3, conductor 8, residual biopulse discharge pipes 9, coarse biogas discharge 10. hydrostatic pressure of biomass H ₁ , hydrostatic pressure of bi pulp H ₂ .

The biogas generator, which is proposed, works as follows: biomass from tank 1 through the biomass supply pipe 2 by gravity, due to the pressure drop Δp _dv = g (ρ _BM · H ₁ - ρ _BP · N ₂ ), the biomass is sent to the active zone of the pipe cavity 4 where anaerobic methanogenic microorganisms, which are in sufficient quantity in the biomass, at the optimum temperature (+30 ... + 35 ° С) turn the biomass into biogas, bioil and water, a mixture of biogas bubbles with the residual biopulse rises to the upper part of the bioreactor body divided into biogas and the residual biopulp, through the pipe 9, the residual biopulse goes for further processing, through the pipe 10, the biogas goes for cleaning and further use.

The invention, which is proposed low-energy, environmentally friendly, capable of becoming an inexhaustible source of high-pressure flammable gas (5-6 MPa).

Claims (1)

A continuous underground biogas generator, consisting of a housing adapted to fill it to a certain level with biomass, a bioreactor loading system, which includes a biomass supply pipe to the bioreactor, a bioreactor discharge system, which includes a residual biopulse discharge pipe and a biogas removal pipe, characterized the fact that the bioreactor body is made in the form of a cylindrical pipe with an end shoe at its lower end, which is mainly located in the well and buried in the ground in such an way m, that its lower part, which houses the active zone of the bioreactor with thermal contact in the rock layer, which has an elevated temperature in the range of 30-35 ° C, which is favorable for the conversion of biomass into biogas, the bioreactor loading system has a biomass tank at the inlet, which is connected to the upper end of the biomass supply pipe to the bioreactor, which extends inside the bioreactor body so that its lower end is placed in the area of the indicated final shoe, the residual biopulse removal pipe is connected to the upper part of the body and the bioreactor is below the biopulp level, and the biogas drain pipe is connected to the upper part of the biogenerator body above the biopulp level, and the bioreactor loading and unloading systems and its body form a flow system that provides continuous gravity-free movement of biomass and biopulp under the action of pressure drop created by the forces of Earth's gravity and gas lift in the annular space of the biogenerator.

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