Device and method for recovering volatile gases generated during aerobic composting

Abstract

The present invention provides a device for recovering volatile gases generated during aerobic composting, comprising an absorption unit, a concentration unit, a waste heat recovery unit, an absorption liquid pool and a concentration liquid pool; the volatile gases generated during aerobic composting enter the absorption unit through the air inlet of the absorption unit and move from the bottom to the top of the absorption unit. The gas absorption liquid is sprayed out by the spray assembly, fully contacts with the volatile gases in the packing layer, and is absorbed by the absorption liquid and then collected by the liquid collection assembly and enters the concentration unit. Under the action of the electric field force, the ions in the absorption liquid move toward the cathode through the cation exchange membrane, and the anions move toward the anode through the anion exchange membrane. Due to the movement of the ions in the absorption liquid, a concentrated liquid chamber and a dilute liquid chamber appear between the anion and cation exchange membranes. The solutions in the concentrated liquid chamber and the dilute liquid chamber enter the concentration liquid pool and the absorption liquid pool respectively through the waste heat recovery unit. The device of the present invention has a good absorption effect on volatile gases during the composting process.

Description

Technical Field

[0001] The invention relates to the technical field of environmental engineering, and in particular to a device and a method for recovering volatile gas generated in an aerobic composting process. Background Art

[0002] With the continuous expansion of my country's economic scale, people's living standards have been significantly improved, the demand for meat has also been increasing, and the scale of my country's breeding industry has been expanding. In the process of rapid development of animal husbandry, a large amount of breeding waste has also been generated.

[0003] Among all the means of harmless treatment and resource utilization of livestock and poultry manure, aerobic composting technology has been widely used due to its advantages of simple operation, economical operation, and technical feasibility. During the aerobic composting process, the air pollutants emitted include NH3, CO2, H2S, VOCs, and harmful microorganisms, among which NH3 and CO2 are the main pollutants. As a precursor of haze, large-scale emission of NH3 will lead to the occurrence of haze and is an important factor in air pollution. Large-scale emission of CO2 will lead to the greenhouse effect. At the same time, the volatilization of NH3 and CO2 will also lead to the loss of N and C in fertilizers, reducing the fertilizer efficiency of organic fertilizers. Therefore, the development of an efficient absorption and electrical concentration system for volatile gases in an aerobic composting reactor is of great significance to the green development of agriculture. Summary of the invention

[0004] The object of the present invention is to provide a device and a method for recovering volatile gases generated during aerobic composting. The recovery device and the recovery method of the present invention have a good absorption effect on the volatile gases generated during aerobic composting.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a device for recovering volatile gases generated during aerobic composting, comprising an absorption unit 1, a concentration unit 2, a first waste heat recovery unit 3-1, a second waste heat recovery unit 3-2, an absorption liquid pool 4 and a concentration liquid pool 5;

[0007] The absorption unit 1 comprises a tower body 11, a packing layer 12 arranged inside the tower body 11, a spray assembly 13 arranged inside the tower body 11 and located above the packing layer 12, a liquid collection assembly 14 arranged at the bottom of the tower body 11, an air inlet 15 is arranged on the side wall at the bottom of the tower body 11, and an air outlet 16 is arranged on the top of the tower body 11; the spray assembly 13 and the liquid collection assembly 14 are in communication;

[0008] The concentration unit 2 comprises a shell, an electrode plate 21 disposed in the shell, and a membrane group pair 22 disposed between the electrode plates 21; a water distributor inlet pipe 28 is disposed on the upper part of the shell, and a water distributor outlet pipe 29 is disposed on the lower part; the electrode plate 21 is connected to a power source; the space between the electrode plate 21 and the membrane group pair 22 constitutes an electrode chamber 23; each membrane group in the membrane group pair 22 comprises a membrane frame 24 on both sides and an ion exchange membrane 25 clamped in the membrane frame 24; the ion exchange membrane 25 is an anion exchange membrane or a cation exchange membrane; the anion exchange membrane and the cation exchange membrane are alternately disposed; the chambers alternately appearing between each membrane group are a dilute liquid chamber 26 and a concentrated liquid chamber 27;

[0009] The liquid in the dilute liquid chamber 26 enters the absorption liquid pool 4 through the first waste heat recovery unit 3-1; the liquid in the concentrated liquid chamber 27 and the electrode chamber 23 enters the concentrated liquid pool 5 through the second waste heat recovery unit 3-2;

[0010] The first waste heat recovery unit 3-1 or the second waste heat recovery unit 3-2 comprises a thermoelectric conversion sheet base 31, a thermoelectric conversion sheet 32 ​​disposed on the thermoelectric conversion sheet base, and a battery pack 33; the thermoelectric conversion sheet 32 ​​and the battery pack 33 are connected by wires;

[0011] The liquid in the dilute liquid chamber 26 enters the absorption liquid pool 4 after the effluent from the first waste heat recovery unit 3 - 1 ; the liquid in the electrode chamber 23 and the concentrated liquid chamber 27 enters the concentrated liquid pool 5 after the effluent from the second waste heat recovery unit 3 - 2 through the pipeline.

[0012] Preferably, the absorption liquid pool 4 is connected to the spray assembly 13, and a pressure pump 6 is arranged between the absorption liquid pool 4 and the spray assembly 13; a main valve 7-1, a first valve 7-2 and a second valve 7-3 are arranged between the pressure pump 6 and the spray assembly 13.

[0013] Preferably, the packing layer 12 includes a partition support, a partition and a packing; the partition support is fixed on the inner wall of the tower body 11; a partition is placed on the partition support; a packing is placed on the partition; and the height of the packing is 1 / 3 of the height of the absorption unit 1.

[0014] Preferably, a conical slope 141 with a central protrusion is provided at the bottom of the liquid collection component 14, and a liquid storage tank 142 is provided at the lowest point on both sides of the conical slope 141; the lower part of the liquid storage tank 142 is connected to the absorption unit liquid outlet pipe 143.

[0015] Preferably, the absorption unit liquid outlet pipe 143 is connected to the water distributor liquid inlet pipe 28 via the water distributor 8 .

[0016] Preferably, the device further comprises an automatic control system for controlling the flow rate of the absorption liquid output from the absorption liquid pool 4 , the air intake volume of the air inlet 15 , and the voltage of the electrode plate 21 of the concentration unit 2 .

[0017] The present invention provides a method for recovering volatile gases generated during aerobic composting based on the device described in the above scheme, comprising the following steps:

[0018] 1) The volatile gas generated by aerobic composting enters the tower body 11 through the air inlet 15. Under the action of the pressure difference between the air inlet and the air outlet, the volatile gas moves from the bottom to the top in the tower body 11. The absorption liquid output from the absorption liquid pool 4 is sprayed into the tower body 11 by the spray assembly. The absorption liquid moves from the upper and / or middle part of the tower body 11 to the lower part under the action of gravity, and fully contacts with the volatile gas in the packing layer 12. The part of the volatile gas that is soluble in the absorption liquid is transferred from the gas phase to the liquid phase, and the liquid is finally collected by the liquid collecting assembly 14;

[0019] 2) The liquid collected by the liquid collection assembly 14 is input into the concentration unit 2. Under the combined action of the electric field and the ion exchange membrane 25, the dilute liquid chamber 26 and the concentrated liquid chamber 27 appear alternately between the membrane group 22;

[0020] 3) The effluent of the liquid in the dilute liquid chamber 26 after passing through the first waste heat recovery unit 3-1 enters the absorption liquid pool 4; the effluent of the liquid in the concentrated liquid chamber 27 and the electrode chamber 23 after entering the second waste heat recovery unit 3-2 through a pipeline enters the concentrated liquid pool 5; the first waste heat recovery unit 3-1 and the second waste heat recovery unit 3-2 convert the recovered heat energy into electrical energy and store it in the battery pack 33.

[0021] Preferably, the flow rate of the absorption liquid output from the absorption liquid pool 4 in step 1) is 4 to 5 m 3 / h.

[0022] Preferably, in step 2), the voltage of the electrode plate 21 of the concentration unit 2 is 20-40V.

[0023] Beneficial effects of the present invention: The present invention provides a device for recovering volatile gases generated during aerobic composting, comprising an absorption unit 1, a concentration unit 2, a first waste heat recovery unit 3-1, a second waste heat recovery unit 3-2, an absorption liquid pool 4 and a concentration liquid pool 5; the volatile gases (mainly CO2 and NH3) generated during aerobic composting enter the absorption unit 1 through the lower air inlet 15 of the absorption unit 1, and move from the bottom to the top of the absorption unit 1 under the action of the pressure difference. A spray assembly 13 is arranged in the middle and upper parts of the absorption unit 1, and the spray assembly 13 is arranged at intervals with the packing layer 12. The gas absorption liquid is sprayed by the spray assembly 13. The absorption liquid fully contacts the volatile gas during the flow of the packing layer 12. The components such as CO2 and NH3 in the gas are absorbed by the absorption liquid and collected by the liquid collection assembly 14 and then enter the concentration unit 2. In the concentration unit 2, cation exchange membranes and anion exchange membranes are arranged alternately, and the anion and cation exchange membranes are separated by a membrane frame 24. The electrode plate 21 is arranged on both sides of the concentration unit 1, and the electrode plate 21 is connected to the power supply. Under the action of the electric field force, cations in the absorption liquid move toward the cathode through the cation exchange membrane, and anions move toward the anode through the anion exchange membrane. Due to the movement of ions in the absorption liquid, a concentrated liquid chamber 27 and a dilute liquid chamber 26 appear between the anion and cation exchange membranes. The solution in the dilute liquid chamber 26 enters the absorption liquid pool 4 through the first waste heat recovery unit 3-1; the solution in the concentrated liquid chamber 27 and the anode chamber (23) enters the concentrated liquid pool 5 through the second waste heat recovery unit 3-2. The thermoelectric conversion plate 32 in the first waste heat recovery unit 3-1 and the second waste heat recovery unit 3-2 realizes the conversion of waste heat into electrical energy under the action of the temperature difference on both sides. The liquid in the absorption liquid pool 4 flows back into the tower body 11 from the spray assembly 13 of the absorption unit 1, realizing the recycling of the absorption liquid. The volatile gas absorption device of the aerobic composting reactor provided by the present invention not only has a good absorption effect on volatile gases in the composting process, but also has the advantages of low operating cost, strong impact load resistance, small footprint and adjustable concentration multiple.

[0024] As an organic whole, the device of the present invention has a significant effect on reducing volatile gas emissions, especially ammonia emissions, in aerobic composting reactors. The present invention integrates the absorption and concentration processes of volatile gases in the aerobic composting process, effectively improving the utilization efficiency of the absorption rate while ensuring the removal rate and operation stability; the present invention can achieve the concentration of ion concentration in the absorption liquid and the recycling of the absorption liquid while absorbing the gas, thereby having the advantages of good absorption effect on volatile gases, strong resistance to impact loads, small volume and adjustable concentration multiples; the present invention recovers the waste heat generated in the aerobic composting process, and stores and reuses it by converting it into electrical energy; the device of the present invention has a significant effect on the absorption and concentration of volatile gases in aerobic composting reactors. Among them, the absorption efficiency of ammonia can reach 85%, and the concentration multiple is 5 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The composition diagram of the device for recovering volatile gases generated in the aerobic composting process of the present invention, wherein 1 is an absorption unit, 2 is a concentration unit, 3-1 is a first waste heat recovery unit, 3-2 is a second waste heat recovery unit, 4 is an absorption liquid tank and 5 is a concentration liquid tank;

[0026] Figure 2 The detailed diagram of the composition of the device for recovering volatile gases generated in the aerobic composting process of the present invention; wherein 11 is a tower body, 12 is a packing layer, 13 is a spray assembly, 14 is a liquid collection assembly, 15 is an air inlet, 16 is an air outlet, 21 is an electrode plate, 22 is a membrane group pair, 23 is an electrode chamber, 26 is a dilute liquid chamber, 27 is a concentrated liquid chamber, 3-1 is a first waste heat recovery unit, 3-2 is a second waste heat recovery unit, 31 is a thermoelectric conversion sheet base, 32 is a thermoelectric conversion sheet, 33 is a battery pack, 4 is an absorption liquid pool, 5 is a concentrated liquid pool, 6 is a pressure pump, 7-1 is a main valve, 7-2 is a first valve, 7-3 is a second valve, and 8 is a water distributor;

[0027] Figure 3 The top view and side view of the absorption unit of the device for recovering volatile gases generated in the aerobic composting process of the present invention; A is a side view, B is a top view, 11 is a tower body, 12 is a packing layer, 13 is a spray assembly, 14 is a liquid collection assembly, and 15 is an air inlet;

[0028] Figure 4 This is a structural detail diagram of the spray assembly in the device for recovering volatile gases generated in the aerobic composting process of the present invention; wherein 131 is a main pipe and 132 is a branch pipe;

[0029] Figure 5 This is a structural detail diagram of the liquid collection assembly in the device for recovering volatile gases generated in the aerobic composting process of the present invention; wherein 14 is the liquid collection assembly, 141 is the conical slope, 142 is the liquid storage tank, and 143 is the liquid outlet pipe of the absorption unit;

[0030] Figure 6 This is a detailed structural diagram of a water distributor in a device for recovering volatile gases generated during aerobic composting according to the present invention; 8 is a water distributor, 28 is a liquid inlet pipe of the water distributor, and 29 is a liquid outlet pipe of the water distributor;

[0031] Figure 7 The top view and side view of the concentrating unit in the device for recovering volatile gases generated in the aerobic composting process of the present invention; A is a side view, B is a top view, 21 is a plate, 22 is a membrane group pair, 25 is an ion exchange membrane, 26 is a dilute liquid chamber, and 27 is a concentrated liquid chamber;

[0032] Figure 8This is a detailed diagram of the membrane group structure of the concentration unit in the device for recovering volatile gases generated in the aerobic composting process of the present invention; wherein 22 is a membrane group pair, 24 is a membrane frame, 25 is an ion exchange membrane, and 241 is a supporting rib;

[0033] Fig. 9 This is a structural detail diagram of the waste heat recovery unit in the device for recovering volatile gases generated in the aerobic composting process of the present invention; wherein 31 is a thermoelectric conversion sheet base, and 32 is a thermoelectric conversion sheet;

[0034] Fig.10 This is an automatic control diagram of the device for recovering volatile gases generated in the aerobic composting process of the present invention. DETAILED DESCRIPTION

[0035] The present invention provides a device for recovering volatile gases generated during aerobic composting, comprising an absorption unit 1, a concentration unit 2, a first waste heat recovery unit 3-1, a second waste heat recovery unit 3-2, an absorption liquid pool 4 and a concentration liquid pool 5;

[0036] The absorption unit 1 comprises a tower body 11, a packing layer 12 arranged inside the tower body 11, a spray assembly 13 arranged inside the tower body 11 and located above the packing layer 12, a liquid collection assembly 14 arranged at the bottom of the tower body 11, an air inlet 15 is arranged on the side wall at the bottom of the tower body 11, and an air outlet 16 is arranged on the top of the tower body 11; the spray assembly 13 and the liquid collection assembly 14 are in communication;

[0037] The concentration unit 2 comprises a shell, an electrode plate 21 disposed in the shell, and a membrane group pair 22 disposed between the electrode plates 21; a water distributor inlet pipe 28 is disposed on the upper part of the shell, and a water distributor outlet pipe 29 is disposed on the lower part; the electrode plate 21 is connected to a power source; the space between the electrode plate 21 and the membrane group pair 22 constitutes an electrode chamber 23; each membrane group in the membrane group pair 22 comprises a membrane frame 24 on both sides and an ion exchange membrane 25 clamped in the membrane frame 24; the ion exchange membrane 25 is an anion exchange membrane or a cation exchange membrane; the anion exchange membrane and the cation exchange membrane are alternately disposed; the chambers alternately appearing between each membrane group are a dilute liquid chamber 26 and a concentrated liquid chamber 27;

[0038] The liquid in the dilute liquid chamber 26 enters the absorption liquid pool 4 through the first waste heat recovery unit 3-1; the liquid in the electrode chamber 23 and the concentrated liquid chamber 27 enters the concentrated liquid pool 5 through the second waste heat recovery unit 3-2;

[0039] The first waste heat recovery unit 3-1 and the second waste heat recovery unit 3-2 independently include a thermoelectric conversion plate base 31, a thermoelectric conversion plate 32 arranged on the thermoelectric conversion plate base, and a battery group 33; the thermoelectric conversion plate 32 and the battery group 33 are connected by wires.

[0040] The device provided by the present invention includes an absorption unit 1, which includes a tower body 11. The bottom of the side wall of the absorption tower is provided with an air inlet 15. As an embodiment of the present invention, the air inlet 15 is connected to the outlet of the gas collection pipe of the intelligent stratified aeration composting reactor system; the intelligent stratified aeration composting reactor system is preferably provided by the patent with application number 201710670003X.

[0041] In the present invention, a packing layer 12 is arranged in the tower body 11. As an embodiment of the present invention, the number of the packing layers is 2, the two packing layers are distributed at intervals, and the distance between the upper packing layer and the top of the tower body is 20 cm, and the distance between the two packing layers is 20 cm.

[0042] In the present invention, the packing layer 12 preferably includes a partition support, a partition and a packing; the partition support is preferably fixed on the inner wall of the tower body 11; the partition is preferably provided with small holes to facilitate the absorption liquid to flow into and out of the packing layer 12; the partition support is preferably provided with a partition; the packing is preferably provided with a packing; the packing is preferably made of a corrosion-resistant material and has a complex spatial configuration to expand the contact area between gas and liquid; the height of the packing is preferably 1 / 3 of the height of the absorption unit 1. The distance between the lower packing layer 12 and the liquid collection assembly 14 is 20 cm.

[0043] In the present invention, the packing layer 12 serves to increase the gas-liquid contact area and strengthen the gas-liquid mass transfer. In the present invention, the packing layer 12 is a Raschig ring packing with a packing diameter of 1 cm and a height of 1 cm. As an embodiment of the present invention, the packing layer has a thickness of 400 mm and a diameter of 25 cm, and the packing layer is a stack of Raschig ring packing.

[0044] In the present invention, the absorption unit also includes a spray assembly 13 arranged in the tower body 11, and the spray assembly 13 is non-contactly arranged above the packing layer 12. As an embodiment of the present invention, the number of the spray assemblies 13 is preferably 2. In order to ensure that the spray liquid of the spray assembly 13 is evenly distributed in the packing layer 12, as an embodiment of the present invention, the distance between the spray assembly 13 and the packing layer 12 is 18 cm.

[0045] As an embodiment of the present invention, the shape of the spray assembly 13 is a fish frame shape; the spray assembly is composed of a main pipe 131 and branch pipes 132 distributed on both sides of the main pipe, and a small hole 132 is opened on the side of the lower part of the branch pipe 131. The opening rate of the small hole is preferably 0.3%, and the function is to evenly spray the absorption liquid onto the packing layer. Figure 4 Among them, the diameter of the main pipe is 1.5 cm, the diameter of the branch pipe is 0.5 cm, and the number of the branch pipes is 14.

[0046] As an embodiment of the present invention, valves are preferably provided on the pipelines connected to each spray assembly 13. The volatile gas moves from bottom to top in the tower body 11, and the absorption liquid moves from top to bottom. During the gas-liquid contact process, CO2 and NH3, which are the main components of the volatile gas, are absorbed by the absorption liquid, collected by the liquid collection assembly 14, and then enter the concentration unit 2; the absorption liquid preferably includes deionized water.

[0047] In the present invention, the volatile gas of tail gas generated in the composting process fully contacts with the absorption liquid on the surface of the filler during the rising process, gas-liquid mass transfer occurs, and the absorption of soluble components in the exhaust gas is achieved. The components that cannot be absorbed are discharged from the exhaust port at the top of the absorption unit, and the absorption liquid is collected by the liquid collection component under the action of gravity.

[0048] In the present invention, the packing layer 12 preferably includes a partition support, a partition and a packing; the partition support is preferably fixed on the inner wall of the tower body 11; the partition is preferably provided with small holes to facilitate the absorption liquid to flow into and out of the packing layer 12; the partition support is preferably provided with a partition; the packing is preferably provided with a packing; the packing is preferably made of corrosion-resistant material and has a complex spatial configuration to expand the contact area between gas and liquid; the height of the packing is preferably 1 / 3 of the height of the absorption unit 1. The partition is provided with small holes to facilitate the passage of gas and absorption liquid while preventing the loss of the packing.

[0049] In the present invention, the absorption unit 1 further comprises a liquid absorption assembly 14 disposed at the bottom of the tower body 11. Figure 5 As an embodiment of the present invention, the bottom of the liquid absorption component 14 is a conical slope 141 with a protrusion in the middle, and a liquid storage tank 142 is arranged at the lowest point on both sides of the conical slope 141. The absorption liquid that seeps down from the filler enters the bottom liquid storage tank 142 along the conical structure slope; the lower part of the liquid storage tank 142 is preferably connected to the absorption unit liquid outlet pipe 143.

[0050] In the present invention, the material of the absorption unit 1 is preferably a corrosion-resistant material, more preferably polypropylene, fiberglass or plexiglass; the structure of the filler is preferably a spatial polyhedron structure with a large surface area; the material of the filler is preferably polypropylene and / or polyethylene, and the filler is in the form of Raschig rings. As an embodiment of the present invention, the filler has a diameter of 1 cm and a height of 1 cm.

[0051] The device provided by the present invention includes a concentration unit 2 connected to the absorption unit 1. In the present invention, the concentration unit 2 includes a shell, an electrode plate 21 arranged in the shell, and a membrane group 22 arranged between the electrode plates 21; as an embodiment of the present invention, each chamber in the concentration unit 2 is connected to the water distributor outlet pipe 29 of the water distributor 8 through a hose, and the liquid collection component 14 is connected to the water distributor inlet pipe 28 of the water distributor 8. The water distributor 8 plays the role of collecting liquid and evenly distributing it. Figure 6 .

[0052] In the present invention, the membrane group is a sandwich structure, with membrane frames on both sides and ion exchange membranes in the middle, wherein the ion exchange membranes are anion or cation exchange membranes. The anion and cation exchange membranes are arranged alternately in the concentration unit 2. The two side plates are connected to a DC regulated power supply, and the cations (NH 4+ , H + ) moves toward the cathode under the action of the electric field, and the anions (CO3 2- OH - ) moves toward the anode under the action of the electric field; the anion exchange membrane aqueous solution has a positive charge, allowing anions to pass through, and the cation exchange membrane aqueous solution has a negative charge, allowing cations to pass through; under the joint action of the electric field and the ion exchange membrane, the dilute liquid chamber and the concentrated liquid chamber appear alternately between the membrane groups of the concentration unit; the liquid in the dilute liquid chamber enters the first waste heat recovery unit 3-1 through a pipeline; the liquid in the concentrated liquid chamber enters the second waste heat recovery unit 3-2 through a pipeline.

[0053] In the present invention, the membrane frame 24 in the concentration unit membrane 2 plays the role of supporting the ion exchange membrane 25. In order to increase the contact area between the ion exchange membrane 25 and water, holes are preferably opened on the membrane frame 24. In order to ensure the flatness of the membrane under the action of water flow, supporting ribs 241 are preferably also provided on the membrane frame 24.

[0054] In the present invention, the electrode plates 21 of the concentration unit 2 are preferably made of corrosion-resistant materials such as titanium coated with ruthenium or graphite, and are arranged on both sides of the concentration unit 2, with one side of the electrode plate connected to the positive electrode of the power supply and the other side connected to the negative electrode of the power supply.

[0055] In the specific implementation of the present invention, the inlet liquid of the concentration unit 2 is divided into three parts, one part is the inlet liquid of the concentrated chamber, one part is the inlet liquid of the dilute chamber, and the other part is the plate liquid. The outlet liquid is also divided into three parts, one part is the concentrated liquid, one part is the dilute liquid, and one part is the plate liquid. The dilute liquid is transported to the first waste heat recovery unit 3-1 through a pipeline, and the plate liquid and the concentrated liquid are transported to the second waste heat recovery unit 3-2 through a pipeline.

[0056] In the present invention, since the aerobic composting process generates heat, heat transfer occurs during the gas-liquid contact process in the absorption unit 1, causing the temperature of the absorption liquid to rise; since the system of the present invention is a continuous flow, the conversion plate base 31 in the waste heat recovery unit can make the thermoelectric conversion plate 32 fully contact with the high-temperature concentrated liquid and the dilute liquid, and the semiconductor structure in the thermoelectric conversion plate 32 generates electrical energy under the action of the temperature difference on both sides, and the generated electrical energy is stored in the battery pack 33 through wires.

[0057] In the present invention, the absorption liquid pool 4 and the concentrated liquid pool 5 are used to store absorption liquid and concentrated liquid respectively. The absorption liquid pool and the concentrated liquid pool are closed structures, and two feed pipes are preferably provided on the top cover. Among them, one feed pipe on the top cover of the concentrated liquid pool 5 is used to feed liquid, and the other feed pipe is used to add sulfuric acid to the concentrated liquid through the feed pipe after running for a certain period of time while exhausting gas, so that the ammonia in the concentrated liquid is converted into ammonium sulfate to realize the resource utilization of N elements. The bottom of the side wall of the concentrated liquid pool 5 is preferably provided with a liquid outlet pipe, and the liquid outlet pipe is preferably provided with a valve to control the outflow of ammonium sulfate concentrate. One feed pipe on the top cover of the absorption liquid pool 4 is used to feed liquid, and the other feed pipe is used to replenish the absorption liquid loss caused by the long-term operation of the system.

[0058] In the present invention, the volatile gas generated during aerobic composting is absorbed by the absorption liquid, and the absorption liquid is concentrated by a concentration means to produce a concentrated liquid and a dilute liquid. The dilute liquid is refluxed to absorb the volatile gas, thereby realizing the repeated use of the absorption liquid. The concentrated liquid can be used as a fertilizer to realize resource utilization.

[0059] In the present invention, a pressure pump 6 is preferably provided between the absorption liquid pool 4 and the absorption unit 1; the absorption liquid in the absorption liquid pool 4 is pressurized by the pressure pump 6 and enters the spray assembly 13 in the absorption unit 1, and is sprayed onto the packing layer 12 by the spray assembly 13 to achieve the reuse of the absorption liquid; a main valve 7-1, a first valve 7-2 and a second valve 7-3 are preferably provided between the pressure pump 6 and the spray assembly 13.

[0060] In the present invention, the device preferably also includes an automatic control system, which is mainly composed of a control cabinet, an ammonia concentration sensor, a gas flow sensor, a conductivity sensor, a pH sensor and a voltage sensor. These sensors transmit the acquired data to the automatic control system and automatically adjust according to the program settings. Fig.10 The automatic control unit monitors the inlet gas concentration, gas flow, absorption liquid pH value, concentration chamber liquid conductivity, dilution chamber liquid conductivity, concentration chamber liquid pH value and dilution chamber liquid pH value. It also dynamically controls the voltage of the electrode plate 21 of the concentration unit 2 and the absorption liquid reflux flow rate to ensure the highest absorption efficiency and maximum concentration multiple of the gas.

[0061] During the specific implementation of the present invention, the absorption liquid inlet and outlet flow rates of the absorption unit 1 and the liquid inlet and outlet flow rates of the concentration unit 2 should be the same to ensure the stable operation of the entire system.

[0062] By adjusting the absorption liquid spray flow rate, the absorption rate of volatile gases in the aerobic composting process can be effectively controlled. By adjusting the plate voltage, the migration rate of ions in the absorption liquid under the electric field and the recovery efficiency of ions can be effectively controlled.

[0063] The present invention provides a method for recovering volatile gases generated during aerobic composting based on the device described in the above scheme, comprising the following steps:

[0064] 1) The volatile gas generated by aerobic composting enters the tower body 11 through the air inlet 15. Under the action of the pressure difference between the air inlet and the air outlet, the volatile gas moves from the bottom to the top in the tower body 11. The absorption liquid output from the absorption liquid pool 4 is sprayed into the tower body 11 by the spray assembly. The absorption liquid moves from the upper and / or middle part of the tower body 11 to the lower part under the action of gravity, and fully contacts with the volatile gas in the packing layer 12. The part of the volatile gas that is soluble in the absorption liquid is transferred from the gas phase to the liquid phase, and the liquid is finally collected by the liquid collecting assembly 14;

[0065] 2) The liquid collected by the liquid collection assembly 14 is input into the concentration unit 2. Under the combined action of the electric field and the ion exchange membrane 25, the dilute liquid chamber 26 and the concentrated liquid chamber 27 appear alternately between the membrane group 22;

[0066] 3) The effluent of the liquid in the dilute liquid chamber 26 after passing through the first waste heat recovery unit 3-1 enters the absorption liquid pool 4; the effluent of the liquid in the concentrated liquid chamber 27 and the electrode chamber 23 after entering the second waste heat recovery unit 3-2 through a pipeline enters the concentrated liquid pool 5; the first waste heat recovery unit 3-1 and the second waste heat recovery unit 3-2 convert the recovered heat energy into electrical energy and store it in the battery pack 33.

[0067] The present invention first allows the volatile gas generated by aerobic composting to enter the tower body 11 through the air inlet 15. Under the action of the pressure difference between the air inlet and the air outlet, the volatile gas moves from the bottom to the top in the tower body 11. The absorption liquid output from the absorption liquid pool 4 is sprayed into the tower body 11 by the spray assembly. The absorption liquid moves from the top and / or middle of the tower body 11 to the bottom under the action of gravity, and fully contacts with the volatile gas in the packing layer 12. The part of the volatile gas that is soluble in the absorption liquid is transferred from the gas phase to the liquid phase, and the liquid is finally collected by the liquid collection assembly 14. The flow rate of the absorption liquid output from the absorption liquid pool 4 is preferably 4 to 5 m / s. 3 As an embodiment, the absorption liquid is deionized water with a resistivity of 18.2 MΩ·cm.

[0068] The liquid collected by the liquid collection assembly 14 of the present invention is input into the concentration unit 2. Under the combined action of the electric field and the ion exchange membrane 25, the dilute liquid chamber 26 and the concentrated liquid chamber 27 appear alternately between the membrane group 22. The voltage of the electrode 21 of the concentration unit 2 is preferably 20-40V.

[0069] In the present invention, the effluent of the liquid in the dilute liquid chamber 26 enters the absorption liquid pool 4 after passing through the first waste heat recovery unit 3-1; the effluent of the liquid in the concentrated liquid chamber 27 enters the concentrated liquid pool 5 after entering the second waste heat recovery unit 3-2 through a pipeline; the first waste heat recovery unit 3-1 and the second waste heat recovery unit 3-2 convert the recovered heat energy into electrical energy and store it in the battery pack 33.

[0070] In the present invention, the concentrated solution is mainly concentrated ammonium carbonate and ammonium bicarbonate solution, and the diluted solution is mainly purified deionized water.

[0071] In the present invention, the absorption process, concentration process and heat recovery process are all continuous processes.

[0072] In the present invention, the concentrated liquid stored in the concentrated liquid pool 5 can be directly applied to the land as liquid fertilizer, or after being stabilized with sulfuric acid, the ammonium carbonate and ammonium bicarbonate in the concentrated liquid pool can be converted into ammonium sulfate and then applied to the land as liquid fertilizer.

[0073] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0074] Example 1

[0075] The absorption liquid is deionized water with a resistivity of 18.2 MΩ·cm. The gas is the volatile gas from the aerobic composting process, which is transported to the air inlet of the device of the present invention through a pipeline, wherein the NH3 concentration is 1.7 g / m 3 , the voltage of the electric concentration system is 30V, and the absorption liquid flow rate is 4.5m 3 / h.

[0076] After being treated by the aerobic composting reactor's volatile gas efficient absorption and electric concentration system, the NH3 removal rate at the upper outlet of the absorption unit was 89%. The pH of the concentrate was 11.25, and the pH of the absorption liquid was 7.03.

[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A device for recovering volatile gases generated during aerobic composting, comprising an absorption unit (1), a concentration unit (2), a first waste heat recovery unit (3-1), a second waste heat recovery unit (3-2), an absorption liquid pool (4) and a concentration liquid pool (5); The absorption unit (1) comprises a tower body (11), a packing layer (12) arranged inside the tower body (11), a spray assembly (13) arranged inside the tower body (11) and located above the packing layer (12), a liquid collection assembly (14) arranged at the bottom of the tower body (11), an air inlet (15) arranged on the side wall of the bottom of the tower body (11), and an air outlet (16) arranged on the top of the tower body (11); the spray assembly (13) and the liquid collection assembly (14) are in a connected state; The concentration unit (2) comprises a shell, an electrode plate (21) arranged in the shell, and a membrane group pair (22) arranged between the electrode plates (21); a water distributor liquid inlet pipe (28) is arranged at the upper part of the shell, and a water distributor liquid outlet pipe (29) is arranged at the lower part; the electrode plate (21) is connected to a power source; the space between the electrode plate (21) and the membrane group pair (22) constitutes an electrode chamber (23); each membrane group in the membrane group pair (22) comprises a membrane frame (24) on both sides and an ion exchange membrane (25) clamped in the membrane frame (24); the ion exchange membrane (25) is an anion exchange membrane or a cation exchange membrane; the anion exchange membrane and the cation exchange membrane are arranged alternately; the chambers alternately appearing between each membrane group are a dilute liquid chamber (26) and a concentrated liquid chamber (27); The liquid in the dilute liquid chamber (26) enters the absorption liquid pool (4) through the first waste heat recovery unit (3-1); the liquid in the concentrated liquid chamber (27) and the electrode chamber (23) enters the concentrated liquid pool (5) through the second waste heat recovery unit (3-2); The packing layer (12) comprises a partition support, a partition and a packing; the partition support is fixed on the inner wall of the tower body (11); a partition is placed on the partition support; a packing is placed on the partition; the height of the packing is 1 / 3 of the height of the absorption unit (1); The absorption liquid pool (4) is in communication with the spray assembly (13), and a pressure pump (6) is provided between the absorption liquid pool (4) and the spray assembly (13); The first waste heat recovery unit (3-1) and the second waste heat recovery unit (3-2) independently comprise a thermoelectric conversion plate base (31), a thermoelectric conversion plate (32) arranged on the thermoelectric conversion plate base, and a battery pack (33); the thermoelectric conversion plate (32) and the battery pack (33) are connected via a wire.

2. The device according to claim 1, characterized in that A main valve (7-1), a first valve (7-2) and a second valve (7-3) are arranged between the booster pump (6) and the spray assembly (13).

3. The device according to claim 1, characterized in that The bottom of the liquid collection component (14) is provided with a conical inclined surface (141) with a central protrusion, and liquid storage tanks (142) are provided at the lowest points on both sides of the conical inclined surface (141); the lower part of the liquid storage tank (142) is connected to an absorption unit liquid outlet pipe (143).

4. The device according to claim 3, characterized in that The absorption unit liquid outlet pipe (143) is connected to the water distributor (8) and the water distributor liquid inlet pipe (28).

5. The device according to claim 1, characterized in that The device also includes an automatic control system for controlling the flow rate of the absorption liquid output from the absorption liquid pool (4), the amount of air intake from the air inlet (15), and the voltage of the electrode plate (21) of the concentration unit (2).

6. A method for recovering volatile gases generated during aerobic composting based on the device according to any one of claims 1 to 5, comprising the following steps: 1) The volatile gas generated by aerobic composting enters the interior of the tower body (11) through the air inlet (15); Under the action of the pressure difference between the inlet and outlet ports, the volatile gas moves from the bottom to the top in the tower body (11), the absorption liquid output from the absorption liquid pool (4) is sprayed into the tower body (11) by the spray assembly, and the absorption liquid moves from the top and / or middle of the tower body (11) to the bottom under the action of gravity, and fully contacts with the volatile gas in the packing layer (12), and the part of the volatile gas that is soluble in the absorption liquid is transferred from the gas phase to the liquid phase, and the liquid is finally collected by the liquid collection assembly (14); 2) The liquid collected by the liquid collection component (14) is input into the concentration unit (2), and under the combined action of the electric field and the ion exchange membrane (25), a dilute liquid chamber (26) and a concentrated liquid chamber (27) appear alternately between the membrane group pair (22); 3) The liquid in the dilute liquid chamber (26) passes through the first waste heat recovery unit (3-1), and the outflow liquid enters the absorption liquid pool (4); the liquid in the concentrated liquid chamber (27) and the electrode chamber (23) enters the second waste heat recovery unit (3-2) through a pipeline, and the outflow liquid enters the concentrated liquid pool (5); the first waste heat recovery unit (3-1) and the second waste heat recovery unit (3-2) convert the recovered heat energy into electrical energy and store it in the battery pack (33).

7. The recycling method according to claim 6, characterized in that: The flow rate of the absorption liquid output from the absorption liquid pool (4) in step 1) is 4-5 m 3 / h.

8. The recycling method according to claim 6, characterized in that: In step 2), the voltage of the electrode plate (21) of the concentration unit (2) is 20-40V.

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