RU2840332C1 - Biogas plant - Google Patents

Abstract

FIELD: biochemistry.

SUBSTANCE: invention relates to biochemistry and is intended for anaerobic fermentation of organic wastes of agricultural production to obtain biogas and organic fertilizers. Biogas plant includes a sealed vertical cylindrical tank with process branch pipes, equipped with a dome and a bottom, and a bubbling mixer installed in the tank. Stirring device is a spiral perforated pipe located along the walls of the reservoir, the turns of which follow the shape of the reservoir. Dome and bottom have the shape of a hemisphere. In the tank there is a vertical frame mixer equipped with vertical and horizontal blades fixed on the central vertical shaft. Holes on spiral pipe are made through vertical at equal distance from each other. Dome of the tank, on which the pressure sensor is installed, is made removable. Temperature regulator is rigidly fixed on the wall of the sealed vertical cylindrical tank. Temperature regulator output is connected to the heat pump control input, the input of which is connected to the buried heat exchanger, and the outlet is connected by pipelines passing through holes in the bottom of the sealed vertical cylindrical tank to heaters located inside the sealed vertical cylindrical tank.

EFFECT: increasing energy efficiency of the biogas plant due to reduction of electric energy consumed by the biogas plant.

1 cl, 1 dwg

Description

The invention relates to biochemistry and is intended for anaerobic fermentation of organic waste from agricultural production to produce biogas and organic fertilizers.

A biogas plant is known (RU 2567649, C12M 1/04, 1/07, C02F 11/04, 3/00, B09B 3/00, 10.11.2015), including a sealed vertical cylindrical tank equipped with a dome and a bottom in the shape of a truncated cone. The tank contains a bubbling mixing device including a spiral perforated pipe located along the walls of the tank and the bottom, as well as a vertical perforated pipe installed in the center of the tank. The turns of the spiral pipe repeat the shape of the tank and the bottom. A loading pipe for feeding biomass, a pressure sensor, a pipe for removing biogas connected to the biogas outlet pipeline are installed on the dome of the tank. The latter is connected to the gas holder. A branch pipe for unloading the processed substrate is installed in the bottom of the tank. The outer part of the tank is wrapped with a heating tape.

The disadvantage of a biogas plant is its low energy efficiency, due to the increased consumption of electrical energy to power the heating tape.

A biogas plant is known (RU 2605312, C12M 1/04, C12M 1/107, 20.12.2016), selected as a prototype, containing a sealed vertical cylindrical tank with process pipes, equipped with a dome and a bottom, a bubbling mixing device installed in the tank, which is a spiral perforated pipe located along the walls of the tank, the turns of which repeat the shape of the tank, the outer part of which is wrapped with a heating tape, connected to a thermostat fixed to the wall of the tank, the dome and bottom have the shape of a hemisphere, a vertical frame mixer is installed in the tank, equipped with vertical and horizontal blades fixed to the central vertical shaft, the lower horizontal blade has a radius of curvature corresponding to the radius of curvature of the bottom of the tank, while the holes on the spiral pipe are made through vertical at equal distances from each other, the dome of the tank is removable.

Since the heating tape is powered by an electrical source, the biogas plant is characterized by increased electrical energy consumption, so low energy efficiency is its main drawback.

The objective of the present invention is to increase the energy efficiency of a biogas plant by reducing the electrical energy consumed by the biogas plant.

The technical result is achieved in that in a biogas plant containing a sealed vertical cylindrical tank with process pipes, equipped with a dome and a bottom, a bubbling mixing device installed in the tank, which is a spiral perforated pipe located along the walls of the tank, the turns of which repeat the shape of the tank, the dome and bottom have the shape of a hemisphere, a vertical frame mixer is installed in the tank, equipped with vertical and horizontal blades fixed on a central vertical shaft, wherein the holes on the spiral pipe are made through vertical at an equal distance from each other, the dome of the tank on which the pressure sensor is installed is made removable, a thermostat is rigidly fixed to the wall of the sealed vertical cylindrical tank, the output of which is connected to the control input of the heat pump, the input of which is connected to a heat exchanger located in the ground, and the output is connected by pipelines passing through the holes in the bottom of the sealed vertical cylindrical tank to heaters located inside a sealed vertical cylindrical tank.

The biogas plant is shown in the drawing.

The biogas plant comprises a vertical sealed cylindrical tank 1 mounted on supports 2, equipped with a dome 3 and a bottom 4 having the shape of a hemisphere. In tank 1 there is a bubbling mixing device, which is a spiral perforated pipe 5, and a vertical frame mixer 6 equipped with horizontal 7 and vertical 8 blades. The horizontal 7 blades of the vertical frame mixer 6 are fixed on a central vertical shaft 9 with a drive 10. The spiral perforated pipe 5 is located along the walls of tank 1. The turns of the spiral perforated pipe 5 repeat the shape of tank 1. The openings 11 on the spiral pipe 5 are made through vertical and are located at an equal distance from each other. The lower end of the spiral perforated pipe 5 is rigidly attached to a steel cylindrical angle 12, connected to a ball valve 13 for feeding biogas. The dome 3 of the tank 1 is removable.

On the dome 3 of the tank 1, a loading branch pipe 14 for feeding the processed biomass, a pressure sensor 15, and a branch pipe 16 for removing biogas are installed. The branch pipe 16 is connected via a biogas outlet pipeline 17 to a gas holder (not shown in the figure). In the bottom 4 of the tank 1, a branch pipe 18 is installed for unloading the processed substrate.

The spiral perforated pipe 5 is connected through a steel angle 12 and a tap 13 to a pipeline 19 for supplying biogas and a compressor connected to a gas tank (not shown in the drawing).

On the outer surface of the wall of the tank 1, a thermostat 20 is rigidly fixed, the output 21 of which is connected to the control input 22 of the heat pump 23 (Baskakov A.P., Munts V.A. Alternative and renewable energy sources. Moscow: Publishing House "BASTET", 2013. P. 35), the input 24 of which is connected to the U-shaped heat exchanger 25, located in the ground at a depth of 10 m to 50 m, and the output 26 is connected by pipelines 27 passing through openings in the bottom 4 of the tank 1, to heaters 28 located inside the tank 1.

The biogas plant works as follows.

To create anaerobic fermentation, water is poured into tank 1 through loading pipe 14 to the upper level of dome 3. Then, some of the water is drained from tank 1 so that pipe 14 remains partially loaded with water. Then, liquefied fresh manure (droppings) with a humidity of 92-93% is loaded into tank 1 through pipe 14 to the upper level of dome 3. Under the influence of the temperature of unheated liquefied fresh manure, thermostat 20 generates a signal that is fed from output 21 to control input 22 of heat pump 23. As a result, heat pump 23 begins to operate.

Natural heat of the earth at a temperature of approximately 10°C heats the liquid in the U-shaped heat exchanger 25, which leads to the transformation of the liquid into gas. The gas pressure increases in the compressor (not shown in the drawing) of the heat pump 23, as a result of which the temperature increases to 50-60°C. Then the gas is cooled in the condenser (not shown in the drawing) of the heat pump 23, giving off thermal energy to the coolant, which enters the heaters 28 through the pipelines 27. As a result of heat exchange, the thermal energy is used to heat fresh manure, which begins to ferment with the release of biogas.

The shape of the dome 3 of the biogas plant forms a container for accumulating the resulting biogas. The pressure in the tank 1 is monitored using the pressure sensor 15. The thermostat 20 automatically switches off the heat pump 23 when the manure temperature reaches 36-38°C and switches it on when it decreases.

In this state, methane fermentation occurs in tank 1. The biogas obtained in tank 1 enters the gas holder through pipe 16 and pipeline 17, where part of it enters the compressor through the pipeline. In order to ensure a uniform temperature inside tank 1, to provide nutrients to methane-forming bacteria, to prevent sedimentary material and a crust under dome 3, which prevents the biogas from exiting, the bubbling mixing device and frame mixer 6 are started every day for 10 minutes. To do this, tap 13 is opened, after which the biogas located in the compressor enters the spiral perforated pipe 5 under pressure through pipeline 19, exits through openings 11, mixing the substrate, accelerating the process of raising the biogas bubbles formed by methane fermentation. When frame mixer 6 with the bubbling device is turned on, all layers of the mass are intensively mixed.

The unloading of processed waste is carried out periodically through branch pipe 18. In this case, the volume of the unloaded mass must correspond to the next dose of loading a fresh portion of the substrate, which eliminates overflow of the tank and clogging of the opening of the branch pipe for the biogas outlet.

The remaining biogas in the gas holder can be used for household needs, and the processed substrate can be used as an organic fertilizer concentrate.

As can be seen, in comparison with the prototype, in which electric energy consumed by the heating tape is used to heat the manure, in the claimed device there is no need for this, since the thermal energy comes from the depths of the earth, and this fact determines the increase in the energy efficiency of the biogas plant.

Claims (1)

A biogas plant comprising a sealed vertical cylindrical tank with process pipes, equipped with a dome and a bottom, a bubbling mixing device installed in the tank, which is a spiral perforated pipe located along the walls of the tank, the turns of which repeat the shape of the tank, the dome and bottom have the shape of a hemisphere, a vertical frame mixer is installed in the tank, equipped with vertical and horizontal blades fixed on a central vertical shaft, wherein the holes on the spiral pipe are made through vertical at an equal distance from each other, the dome of the tank on which the pressure sensor is installed is made removable, a thermostat is rigidly fixed to the wall of the sealed vertical cylindrical tank, characterized in that the outlet of the thermostat is connected to the control input of the heat pump, the input of which is connected to a heat exchanger located in the ground, and the outlet is connected to heaters by pipelines passing through the holes in the bottom of the sealed vertical cylindrical tank, located inside a sealed vertical cylindrical tank.