A combined heat and power biogas utilization system

Abstract

This invention discloses a combined heat and power (CHP) biogas utilization system, relating to the field of biogas utilization technology. It includes a biogas fermenter, a biogas desulfurization module connected to the fermenter, a gas storage module connected to the desulfurization module, and a CHP module connected to the storage module. The desulfurization module performs wet and dry desulfurization on the biogas. A generator set uses the desulfurized and purified biogas as fuel to output low-voltage AC power, which is high-voltage electricity conforming to grid standards. A lithium bromide absorption chiller uses the high-temperature flue gas from the generator set as a driving heat source, converting high-grade waste heat into cold energy. An ORC waste heat power generation unit recovers medium-grade waste heat from the generator set's cylinder liner cooling water, generating low-voltage AC power and providing auxiliary heating / insulation for the wet desulfurization unit. In summary, this system achieves efficient and deep coupling of four major systems: biogas fermentation, biogas purification, generator set, and waste heat recovery.

Description

Technical Field

[0001] This invention relates to the field of biogas utilization technology, specifically to a combined heat and power biogas utilization system. Background Technology

[0002] With the increasing global demand for clean energy and the growing awareness of environmental protection, biogas, as a renewable and clean energy source, has received widespread attention. Biogas mainly comes from the anaerobic digestion process of organic matter such as agricultural waste, animal manure, and organic waste. Its main components are methane and carbon dioxide, and it has the characteristics of high calorific value and low pollution.

[0003] Combined heat and power (CHP) systems are a promising technology with high energy efficiency, low carbon emissions, and flexible load regulation capabilities. Biogas-based CHP systems are an important technological means to realize the resource recycling of livestock and poultry breeding waste. However, there are still some problems in the practical application of biogas utilization systems.

[0004] On the one hand, biogas usually contains impurities such as hydrogen sulfide. Hydrogen sulfide can not only corrode equipment, but also affect the combustion efficiency and power generation performance of biogas. Therefore, effective desulfurization technology is needed to ensure the quality of biogas. On the other hand, how to efficiently utilize the waste heat generated during biogas power generation and improve the comprehensive utilization rate of energy is also an urgent problem to be solved.

[0005] Therefore, there is an urgent need for a high-efficiency, stable and environmentally friendly cogeneration biogas utilization system. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a combined heat and power biogas utilization system.

[0007] The technical solution of the present invention: a cogeneration biogas utilization system, comprising a biogas fermenter, a biogas desulfurization module connected to the biogas fermenter, a gas storage module connected to the biogas desulfurization module, and a cogeneration module connected to the gas storage module; The biogas desulfurization module includes a wet desulfurization unit, a biogas refrigerated dryer, and a dry desulfurization unit; The combined heat and power module includes a gas booster connected to a gas storage module, a generator set connected to the gas booster, a lithium bromide absorption chiller and an ORC waste heat power generation unit connected to the generator set. The lithium bromide absorption chiller is connected to the high-temperature flue gas outlet of the generator set. The refrigerant outlet pipe of the lithium bromide absorption chiller is connected to the temperature control jacket of the biogas digester and the external living area. A flow regulating valve is provided at the connection with the temperature control jacket of the biogas digester, and a three-way diverter valve is provided at the connection with the external living area. The ORC waste heat power generation unit includes an ORC evaporator connected to the cylinder liner cooling water outlet of the generator set and vaporizing the waste heat fed into the generator set to form high-pressure steam, an expander connected to the ORC evaporator, and an ORC generator coaxially connected to the expander. The cooling water outlet pipe of the ORC evaporator is connected to the biogas desulfurization module. The low-voltage AC power output by the generator set and the ORC generator is rectified into high-voltage power conforming to the grid standard by the ORC grid-connected inverter.

[0008] Furthermore, after the biogas is desulfurized by the biogas desulfurization module, the generator set uses the desulfurized and purified biogas as fuel to drive the generator through combustion, outputting low-voltage AC power and rectifying it into high-voltage power that meets the grid standards. The lithium bromide absorption chiller converts the high-grade waste heat of the generator set into cold energy, part of which provides cold energy for external loads, and the other part is sent to the temperature control jacket of the biogas digester. The ORC waste heat power generation unit recovers the medium-grade waste heat of the generator set's cylinder liner cooling water, and then generates low-voltage AC power through the ORC generator and rectifies it into low-voltage power that meets the grid standards. The low-grade waste heat generated by the ORC generator provides auxiliary heating for the absorbent liquid of the wet desulfurization unit. The high-grade waste heat temperature of the generator set is 350-500℃, the medium-grade waste heat temperature of the generator set is 85-90℃, and the low-grade waste heat temperature of the ORC generator is 40-55℃.

[0009] Explanation: By introducing a combined heat and power (CHP) module as a hub for cross-system energy transfer, efficient and deep coupling of four major systems—biogas fermentation, biogas purification, generator set, and waste heat recovery—is achieved.

[0010] Furthermore, the dry desulfurization unit is composed of several dry desulfurization towers connected in series with a biogas cold dryer.

[0011] Explanation: When the dry desulfurization unit is in use, biogas first enters the first-stage dry desulfurization tower, where it reacts initially with the desulfurizing agent to remove most of the H2S. The incompletely purified biogas then enters subsequent dry desulfurization towers, where it reacts a second and third time with fresh desulfurizing agent, further reducing the H2S concentration and meeting the stringent gas quality requirements of the gas generator sets in the cogeneration module. Simultaneously, during series operation, the load of the desulfurizing agent in each dry desulfurization tower is evenly distributed, with the desulfurizing agent in the first stage being consumed preferentially. Subsequent dry desulfurization towers serve as "backup purification layers," preventing rapid failure of the desulfurizing agent in a single tower due to localized overload, reducing the frequency of desulfurizing agent replacement, and lowering operating costs.

[0012] Furthermore, the corrosion inhibitor addition assembly includes a placement cylinder fastened to the absorbent storage tank and having an arc-shaped notch at the bottom; several spray cylinders distributed circumferentially at the bottom of the placement cylinder and having several spray holes on the inner wall; a folded flexible cylinder connected to each of the spray cylinders; a stirring cylinder connected to the top of the arc-shaped notch via a hydraulic cylinder and having linkage levers on the outer wall circumferentially corresponding to each of the folded flexible cylinders; and several horizontal stirring rods located on the outer wall of the stirring cylinder and at the bottom of each linkage lever. A one-way valve is provided at the connection between the spray cylinder and the placement cylinder.

[0013] Explanation: The purpose of the corrosion inhibitor addition component is to ensure that the corrosion inhibitor is evenly dispersed in the absorbent liquid and to achieve equipment corrosion protection through the "adsorption film / passivation film" mechanism. In specific use, the corrosion inhibitor is first injected into the placement cylinder. Since the bottom of the placement cylinder is connected to the spray cylinder and a one-way valve is installed at the connection, it can prevent the absorbent liquid from flowing back. The corrosion inhibitor can be sprayed into the absorbent liquid storage tank in the form of a mist through the spray holes on the inner wall of the spray cylinder. At the same time, the hydraulic cylinder drives the stirring cylinder to move up and down, and the linkage lever on the outer wall of the stirring cylinder can drive the extension and retraction of the folding soft cylinder to further expand the spray range of the corrosion inhibitor and avoid local corrosion inhibitor concentrations that are too high or too low. After the atomized corrosion inhibitor is fully mixed with the absorbent liquid, it enters the wet desulfurization tower with the circulating pump. The corrosion inhibitor molecules can preferentially adsorb onto the metal surfaces of the tower body, pipes and other metals to form a dense adsorption film. This adsorption film can isolate ions from contact with the metal surface, inhibit electrochemical corrosion reactions and reduce acid corrosion.

[0014] Furthermore, the bottom of the absorbent storage tank and located directly below the stirring cylinder is provided with an installation base cylinder, the upper end of the installation base cylinder is provided with an annular sliding block, the bottom end of the stirring cylinder is provided with a sliding recess, and the annular sliding block is slidably connected to the inner wall of the sliding recess.

[0015] Explanation: The annular sliding block is embedded in the sliding recess of the mixing cylinder, forming a "radial limiting + axial sliding" fit. The radial limiting can restrict the horizontal displacement of the mixing cylinder, preventing the linkage lever from failing to accurately drive the extension and retraction of the folding soft cylinder due to the shaking of the mixing cylinder when the hydraulic cylinder drives the mixing cylinder to move up and down, or the horizontal stirring rod from colliding with the inner wall of the absorbent liquid storage tank. The axial sliding can ensure that the mixing cylinder can move smoothly in the vertical direction.

[0016] The beneficial effects of this invention are: In operation, the combined heat and power (CHP) biogas utilization system of this invention performs wet and dry desulfurization on the biogas fermentation tank via a biogas desulfurization module before introducing it into the CHP module. The generator set uses the desulfurized and purified biogas as fuel, driving the generator through combustion and outputting low-voltage AC power, which is then rectified by an ORC grid-connected inverter to high-voltage electricity conforming to grid standards. The lithium bromide absorption chiller uses the high-temperature flue gas from the generator set as a driving heat source, converting high-grade waste heat into cooling energy through an absorption-desorption cycle of lithium bromide solution. This provides cooling energy to external loads. On the one hand, it provides cooling energy, and on the other hand, it delivers it to the temperature control jacket of the biogas digester through the outlet pipeline to provide stable temperature control for the biogas digester and ensure gas production efficiency. The ORC waste heat power generation unit recovers the medium-grade waste heat of the cylinder liner cooling water of the generator set. On the one hand, it generates low-voltage AC power through the ORC generator, and on the other hand, it provides auxiliary heating / insulation for the absorbent liquid of the wet desulfurization unit or the biogas refrigerated dryer. In short, this system introduces a cogeneration module as a hub for cross-system energy transfer to achieve efficient and deep coupling of the four major systems: biogas fermentation, biogas purification, generator set and waste heat recovery. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the placement tube of the present invention; Figure 3 This is a schematic diagram of the external structure of the placement tube of the present invention; Figure 4 This is a schematic diagram of the internal structure of the concentration regulating box of the present invention; Figure 5 This is a top view of the connection between the rotating gear and the annular rotating plate of the present invention; Figure 6 This is a schematic diagram of the installation structure of the concentrate addition tank of the present invention; Figure 7 This is the mind map of the present invention.

[0018] Among them, 1-biogas fermentation tank, 2-biogas desulfurization module, 20-wet desulfurization unit, 200-wet desulfurization tower, 201-absorbent storage tank, 202-air extraction pump, 203-regeneration reactor, 204-circulation pump, 205-concentration adjustment component, 206-corrosion inhibitor addition component, 207-plate and frame filter press, 208-installation base cylinder, 2080-annular sliding block, 21-biogas refrigerated dryer, 22-dry desulfurization unit, 22 0-Dry desulfurization tower; 23-Flow control valve; 24-H2S sensor; 25-Placement cylinder; 250-Arc-shaped notch; 251-Transparent observation window; 26-Spray cylinder; 260-Spray hole; 261-Check valve; 27-Folded flexible cylinder; 28-Agitator; 280-Hydraulic cylinder; 281-Linkage lever; 282-Sliding notch; 283-Pulling block; 29-Horizontal agitator rod; 3-Gas storage module; 4-Cogeneration module. 40-Gas turbocharger, 41-Generator set, 42-Lithium bromide absorption chiller, 420-Generator, 421-Condenser, 422-Throttle valve, 423-Evaporator, 424-Absorber, 43-ORC waste heat power generation unit, 430-ORC evaporator, 431-Expander, 432-ORC generator, 433-ORC grid-connected inverter, 44-Flow regulating valve, 45-Three-way diverter valve, 50-Mounting notch 51-Concentration regulating box, 510-Annular rotating plate, 511-Horizontal annular plate, 512-Rotating gear, 513-Stirring crossbar, 514-Stirring blade, 52-Clear water tank, 520-Adding branch pipe, 521-Solenoid valve, 53-Concentrated liquid adding box, 530-Adding vertical pipe, 531-Horizontal adding pipe, 532-Dispersing hole, 533-Cover plate, 534-Electromagnetic chuck, 54-Annular metal sheet, 55-Annular sliding groove. Detailed Implementation

[0019] Example 1 like Figure 1 , 7 As shown, a combined heat and power biogas utilization system includes a biogas digester 1, a biogas desulfurization module 2 connected to the biogas digester 1, a gas storage module 3 connected to the biogas desulfurization module 2, and a combined heat and power module 4 connected to the gas storage module 3. The biogas desulfurization module 2 includes a wet desulfurization unit 20, a biogas refrigerated dryer 21, and a dry desulfurization unit 22. The wet desulfurization unit 20, the biogas refrigerated dryer 21, and the dry desulfurization unit 22 all adopt existing technologies. For example, the wet desulfurization unit 20 can adopt the CWS-1000 Changji wet desulfurization system, the biogas refrigerated dryer 21 can adopt the Xinlong brand biogas purification and water removal dryer TQ460, and the dry desulfurization unit 22 can adopt the SDS-50 Yili dry SDS desulfurization equipment. The cogeneration module 4 includes a gas booster 40 connected to the gas storage module 3, a generator set 41 connected to the gas booster 40, a lithium bromide absorption chiller 42 connected to the generator set 41, and an ORC waste heat power generation unit 43. The gas storage module 3, the gas booster 40, and the generator set 41 all adopt existing technologies. For example, the gas storage module 3 can adopt a gas storage device of model CRVZS-0.1, the gas booster 40 can adopt a natural gas engine of model HE500WG, and the generator set 41 can adopt a generator set of model QSZ13-G3. The lithium bromide absorption chiller 42 is connected to the high-temperature flue gas outlet of the generator set 41. The refrigerant outlet pipe of the lithium bromide absorption chiller 42 is connected to the temperature control jacket of the biogas digester 1 and the external living area. A flow regulating valve 44 is provided at the connection with the temperature control jacket of the biogas digester 1, and a three-way diverter valve 45 is provided at the connection with the external living area. The lithium bromide absorption chiller 42 includes a generator 420 connected to the high-temperature flue gas outlet of the generator set 41, a condenser 421 connected to the generator 420 via a steam pipe, a throttling valve 422 connected to the condenser 421 via a liquid refrigerant pipe, an evaporator 423 connected to the throttling valve 422 via a low-pressure pipe, and an absorber 424 connected to the evaporator 423 via a low-pressure pipe. The outlet pipe of the absorber 424 is connected to the temperature control jacket of the biogas digester 1 and to the external living area. The lithium bromide absorption chiller adopts existing technology, such as the Carrier 16JH steam-type single-effect absorption chiller unit, model 16JH010-159.

[0020] ORC waste heat power generation unit 43 includes an ORC evaporator 430 connected to the cylinder liner cooling water outlet of generator set 41 and vaporizing the waste heat fed into generator set 41 to form high-pressure steam, an expander 431 connected to ORC evaporator 430, and an ORC generator 432 coaxially connected to expander 431. The cooling water outlet pipe of ORC evaporator 430 is connected to biogas desulfurization module 2. The low-voltage AC power output by generator set 41 and ORC generator 432 is rectified into high-voltage power conforming to grid standards by ORC grid-connected inverter 433. The ORC waste heat power generation unit 43 adopts existing technology, such as Turboden T100 type ORC waste heat generator set. The corrosion inhibitor is an organic amine corrosion inhibitor, and the absorbent is an iron-containing complex. The weight ratio of the corrosion inhibitor to the absorbent is 1:3. Among them, the organic amine corrosion inhibitor is triethanolamine, and the iron-containing complex is ethylenediaminetetraacetic acid iron complex. After the biogas is desulfurized by the biogas desulfurization module 2, the generator set 41 uses the desulfurized and purified biogas as fuel to drive the generator through combustion, outputting low-voltage AC power and rectifying it into high-voltage power that meets the grid standard. The lithium bromide absorption chiller 42 converts the high-grade waste heat of the generator set 41 into cold energy. Part of the cold energy is provided to the external load, and the other part is sent to the temperature control jacket of the biogas fermentation tank 1. The ORC waste heat power generation unit 43 recovers the medium-grade waste heat of the cylinder liner cooling water of the generator set 41. Then, the ORC generator 432 generates low-voltage AC power and rectifies it into low-voltage power that meets the grid standard. The low-grade waste heat generated by the ORC generator 432 provides auxiliary heating for the absorbent liquid of the wet desulfurization unit 20. The high-grade waste heat temperature of the generator set 41 is 350°C, the medium-grade waste heat temperature of the generator set 41 is 85°C, and the low-grade waste heat temperature of the ORC generator 432 is 40°C.

[0021] This embodiment also discloses the working principle of a combined heat and power biogas utilization system, including the following steps: S1. Biogas from biogas digester 1 is pumped into wet desulfurization unit 20 via vacuum pump 202. Wet desulfurization unit 20 uses "iron-containing complex absorbent" as the desulfurizing agent. When biogas is introduced into the absorbent, H2S reacts chemically with the iron-containing complex and is fixed and removed. Simultaneously, organic amine corrosion inhibitors are added to prevent corrosion of equipment and pipelines by the absorbent. The biogas after wet desulfurization carries a large amount of water vapor, which is cooled and dehydrated by biogas dryer 21. Then, the dried biogas undergoes deep desulfurization in dry desulfurization unit 22. The adsorption of dry desulfurizing agents such as activated carbon and iron oxide further removes residual H2S, reducing the H2S content in the biogas to <20 mg / m³. 3 ; S2. When the gas production rate of biogas digester 1 is greater than the gas consumption of generator set 41, the excess biogas is stored in gas storage module 3. When the gas production rate of biogas digester 1 is lower than the gas consumption of generator set 41, gas storage module 3 releases biogas to ensure stable gas supply to generator set 41 and prevent shutdown. S3. The biogas output from the gas storage module 3 is pressurized by the gas booster 40 and then fed into the combustion chamber of the generator set 41. After mixing with air, it is ignited and burned, generating high-temperature and high-pressure flue gas to drive the internal combustion engine and drive the generator set 41 to generate electricity, directly outputting low-voltage AC power. S4. The high-grade heat generated by the generator set 41 is fed into the lithium bromide absorption chiller 42, where it is absorbed by the lithium bromide solution inside the lithium bromide absorption chiller 42 and gradually converted into cold energy. Part of the cold energy is fed into the "temperature control jacket" of the biogas digester 1, and the other part of the cold energy is transported to the external living area through pipelines and connected to the air conditioning system to provide a cold source for residents or buildings. S5. The medium-grade heat generated by the cylinder liner cooling water of generator set 41 is introduced into ORC evaporator 430, and the organic working medium inside ORC evaporator 430 is heated by the cylinder liner cooling water, causing the organic working medium to vaporize and form high-pressure steam. At this time, the high-pressure steam drives the expander impeller to rotate, converting thermal energy into mechanical energy. Meanwhile, ORC generator 432 rotates synchronously to generate low-voltage alternating current. In ORC evaporator 430, the temperature of the cylinder liner cooling water decreases after releasing heat. Since the cooling water outlet pipe of ORC evaporator 430 is connected to biogas desulfurization module 2, the low-grade waste heat of ORC evaporator 430 cooling water provides auxiliary heating / insulation for the absorbent liquid of wet desulfurization unit 20 or biogas refrigerated dryer 21, further utilizing the waste heat. S6, generator set 41 and ORC generator 432 all output low-voltage AC power, which is rectified and boosted by ORC grid-connected inverter 433 to be converted into high-voltage power that meets the national grid standards, so as to realize grid-connected power generation and supply power to the external grid.

[0022] Example 2 The difference between this embodiment and Embodiment 1 is that: The corrosion inhibitor is an organic amine-based corrosion inhibitor, and the absorbent is an iron-containing complex. The weight ratio of the corrosion inhibitor to the absorbent is 1:4.

[0023] After the biogas is desulfurized by the biogas desulfurization module 2, the generator set 41 uses the desulfurized and purified biogas as fuel to drive the generator through combustion, outputting low-voltage AC power and rectifying it into high-voltage power that meets the grid standard. The lithium bromide absorption chiller 42 converts the high-grade waste heat of the generator set 41 into cold energy. Part of the cold energy is provided to the external load, and the other part is sent to the temperature control jacket of the biogas fermentation tank 1. The ORC waste heat power generation unit 43 recovers the medium-grade waste heat of the cylinder liner cooling water of the generator set 41. Then, the ORC generator 432 generates low-voltage AC power and rectifies it into low-voltage power that meets the grid standard. The low-grade waste heat generated by the ORC generator 432 provides auxiliary heating for the absorbent liquid of the wet desulfurization unit 20. The high-grade waste heat temperature of the generator set 41 is 500℃, the medium-grade waste heat temperature of the generator set 41 is 90℃, and the low-grade waste heat temperature of the ORC generator 432 is 55℃.

[0024] Example 3 The difference between this embodiment and Embodiment 2 is that: The wet desulfurization unit 20 includes a wet desulfurization tower 200, an absorbent storage tank 201 connected to the upper end of the wet desulfurization tower 200 and equipped with a flow control valve 23 at the connection point, an air pump 202 for connecting an external manure fermentation device and the wet desulfurization tower 200 and equipped with an H2S sensor 24 at the connection point, a regeneration reactor 203 and a circulation pump 204 for connecting the bottom end of the wet desulfurization tower 200 and the absorbent storage tank 201, a concentration adjustment component 205 and a corrosion inhibitor addition component 206 located at the absorbent storage tank 201, and a plate and frame filter press connected to the regeneration reactor 203. 207. The biogas dryer 21 is connected to the outlet of the wet desulfurization tower 200. The wet desulfurization tower 200, flow control valve 23, H2S sensor 24, extraction pump 202, regeneration reactor 203, circulation pump 204, plate and frame filter press 207, concentration adjustment component 205, and corrosion inhibitor addition component 206 all utilize existing technologies. For example, the wet desulfurization tower 200 can be an FGD-1000 type wet desulfurization tower, the flow control valve 23 can be a DVC6200 type flow control valve, and the H2S sensor 24 can be an Alphasense type. For the H2S-B4 type H2S sensor, the vacuum pump 202 can be a JGR-50 type vacuum pump, the regeneration reactor 203 can be a ZX-1500 type regeneration reactor, the circulation pump 204 can be a KQSN300-M6 / 450 type circulation pump, the plate and frame filter press 207 can be an XMAZ100 / 1000-U type plate and frame filter press, the concentration adjustment component 205 can be a P056-398TI type metering pump and an L-Dens 7400 type online concentration meter, and the corrosion inhibitor addition component 206 can be an SK type static mixer; The wet desulfurization unit 20 is the core component of the biogas desulfurization module 2, achieving preliminary and efficient removal of H2S. During operation, biogas from the biogas digester 1 is pumped to the wet desulfurization tower 200 via the extraction pump 202. Simultaneously, the H2S sensor 24 monitors the H2S concentration in the biogas in real time, and the monitoring data is transmitted synchronously to the external control system as the basis for subsequent absorption liquid concentration adjustment. The absorption liquid is quantitatively delivered to the top of the wet desulfurization tower 200 via the flow control valve 23, forming a liquid film through a downward spray. Simultaneously, biogas flows upward from the bottom of the wet desulfurization tower 200, and the two flow in opposite directions within the tower's packing layer. The process involves contact and full reaction to convert H2S into water-soluble substances, achieving initial removal of H2S from biogas. The desulfurized biogas is then discharged from the top of the wet desulfurization tower 200 and enters the biogas refrigerated dryer 21 for dehydration. The "rich liquid" after absorbing H2S flows out from the bottom of the wet desulfurization tower 200 and is transported to the regeneration reactor 203 by the circulating pump 204 for oxidation reaction. It is then passed into the plate and frame filter press 207 for high-pressure extrusion to achieve solid-liquid separation. The entire process follows a closed-loop flow of "biogas introduction - absorption reaction - absorbent regeneration - by-product treatment" to ensure desulfurization efficiency and equipment stability. The dry desulfurization unit 22 is composed of several dry desulfurization towers 220 connected in series with the biogas dryer 21. The dry desulfurization towers 220 adopt existing technologies, such as the TS-2000 dry desulfurization tower. When the dry desulfurization unit 22 is in use, the biogas first enters the first-stage dry desulfurization tower 220 and reacts initially with the desulfurizing agent in the dry desulfurization tower 220 to remove most of the H2S. The biogas that is not completely purified then enters the subsequent dry desulfurization tower 220 and reacts with the fresh desulfurizing agent a second and third time, which can further reduce the H2S concentration and meet the strict requirements of the gas generator set 41 in the cogeneration module 4 for gas quality. At the same time, when operating in series, the load of the desulfurizing agent in each dry desulfurization tower 220 is evenly distributed. The desulfurizing agent in the first stage is consumed first, and the subsequent dry desulfurization tower 220 serves as a "backup purification layer". This can prevent the desulfurizing agent in a single tower from failing rapidly due to local overload, reduce the frequency of desulfurizing agent replacement, and reduce operating costs.

[0025] Example 4 The difference between this embodiment and Embodiment 3 is that: like Figure 4 , 5 As shown in Figure 6, the concentration adjustment assembly 205 includes a concentration adjustment box 51 with an upper mounting recess 50 and its side wall connected to the absorbent storage box 201 via a connecting pipe, a clear water tank 52 located outside the concentration adjustment box 51, and a concentrated liquid addition box 53 located at the mounting recess 50. The bottom end of the clear water tank 52 is connected to the concentration adjustment box 51 via four addition branch pipes 520, and a solenoid valve 521 is provided at the connection. The bottom end of the concentrated liquid addition box 53 is connected to an addition vertical pipe 530, and 12 horizontal addition pipes 531 are provided from top to bottom on the addition vertical pipe 530. Each horizontal addition pipe 531 is provided with 20 dispersing holes 532. A cover plate 533 is fastened to the upper end of the concentrated liquid addition box 53. The solenoid valve 521 adopts existing technology, such as the VSPD-LN2M type solenoid valve. When in use, the concentration adjustment component 205 uses the H2S sensor 24 to detect the volume concentration of H2S in biogas in real time. If the detected H2S concentration is higher than the threshold, the absorbent in the concentrated liquid addition tank 53 is injected into the concentration adjustment tank 51 through the addition vertical pipe 530 and the liquid distribution hole 532 of the horizontal addition pipe 531 to increase the overall concentration of the absorbent. When the detected H2S concentration is lower than the threshold, the solenoid valve 521 is opened and clean water is injected into the concentration adjustment tank 51 through the addition branch pipe 520 to dilute the concentration of the absorbent. Through the "adjust as needed" mode, it can avoid incomplete removal of H2S due to the low concentration of absorbent and avoid waste of reagents due to the high concentration, ensuring that the wet desulfurization unit 20 is always in a state of sufficient reaction and the highest reagent utilization rate. The upper end of the mounting recess 50 is provided with an annular metal plate 54, and the bottom edge of the cover plate 533 is provided with three electromagnetic chucks 534. The concentrated liquid addition tank 53 is movably installed in the mounting recess 50 by the magnetic attraction between the electromagnetic chucks 534 and the annular metal plate 54, which facilitates disassembly and installation. The electromagnetic chucks 534 adopt existing technology, such as the electromagnetic chuck of model ESZ30.80. The concentration regulating box 51 has an annular sliding groove 55 on its side wall. Annular rotating plates 510 are respectively provided on the concentration regulating box 51 and on the inner and outer sides of the annular sliding groove 55. The two annular rotating plates 510 are connected by a horizontal annular plate 511 that crosses the annular sliding groove 55. The side wall of the outer annular rotating plate 510 is a gear structure, and the annular rotating plate 510 is meshed with a rotating gear 512 driven by a motor. The inner wall of the inner annular rotating plate 510 is provided with four stirring crossbars 513 along the circumference. Each stirring crossbar 513 is rotatably connected with 16 stirring blades 514. When adjusting the concentration of the absorbent, the rotating gear 512 is driven by a motor to rotate, and the outer annular rotating plate 510 meshing with it rotates synchronously along the circumference of the annular sliding groove 55. The outer annular rotating plate 510 drives the inner annular rotating plate 510 to rotate synchronously through the horizontal annular plate 511, which in turn causes the stirring crossbar 513 on the inner wall of the inner annular rotating plate 510 to make a circular motion. When the stirring crossbar 513 rotates, the stirring blades 514 on its surface fully stir the absorbent, ensuring that the absorbent reaches a uniform concentration before entering the wet desulfurization tower 200, thereby further improving the desulfurization stability.

[0026] Example 5 The difference between this embodiment and embodiment 4 is that: like Figure 2 , 3 As shown, the corrosion inhibitor addition component 206 includes a placement cylinder 25 that is fastened to the absorbent storage tank 201 and has an arc-shaped notch 250 at the bottom; four spray cylinders 26 that are distributed circumferentially at the bottom of the placement cylinder 25 and have 20 spray holes 260 on the inner wall; a folding flexible cylinder 27 that is connected to the spray cylinders 26 one by one; a stirring cylinder 28 that is connected to the top of the arc-shaped notch 250 through a hydraulic cylinder 280 and has linkage levers 281 that are circumferentially connected to the folding flexible cylinders 27; and four horizontal stirring rods 29 that are located on the outer wall of the stirring cylinder 28 and at the bottom of each linkage lever 281. A one-way valve 261 is provided at the connection between the spray cylinder 26 and the placement cylinder 25. The hydraulic cylinder 280 and the one-way valve 261 adopt existing technology. For example, the hydraulic cylinder 280 can be a CJT210 type hydraulic cylinder, and the one-way valve 261 can be a CV-03G type one-way valve. The purpose of the corrosion inhibitor addition component 206 is to ensure that the corrosion inhibitor is uniformly dispersed in the absorbent liquid and to achieve equipment corrosion protection through the "adsorption film / passivation film" mechanism. In specific use, the corrosion inhibitor is first injected into the placement cylinder 25. Because the bottom end of the placement cylinder 25 is connected to the spray cylinder 26, and a one-way valve 261 is provided at the connection point to prevent backflow of the absorbent liquid, the corrosion inhibitor can be sprayed into the absorbent liquid storage tank 201 in a mist form through the spray holes 260 on the inner wall of the spray cylinder 26. Simultaneously, the hydraulic cylinder 280 drives the agitator... The mixing drum 28 moves up and down, and the linkage lever 281 on the outer wall of the mixing drum 28 can drive the folding flexible tube 27 to extend and retract, further expanding the spraying range of the corrosion inhibitor and avoiding excessively high or low local corrosion inhibitor concentrations. After the atomized corrosion inhibitor is fully mixed with the absorbent, it enters the wet desulfurization tower 200 with the circulating pump 204. The corrosion inhibitor molecules can preferentially adsorb onto the metal surfaces of the tower body, pipes, etc., forming a dense adsorption film. This adsorption film can isolate ions from contacting the metal surface, inhibit electrochemical corrosion reactions, and reduce acid corrosion. A mounting base 208 is provided at the bottom of the absorbent storage tank 201 and directly below the stirring cylinder 28. An annular sliding block 2080 is provided at the upper end of the mounting base 208, and a sliding recess 282 is provided at the bottom of the stirring cylinder 28. The annular sliding block 2080 is slidably connected to the inner wall of the sliding recess 282. The annular sliding block 2080 is embedded in the sliding recess 282 of the stirring cylinder 28, forming a "radial limiting + axial sliding" cooperation relationship. The radial limiting can restrict the horizontal displacement of the stirring cylinder 28, and prevent the linkage lever 281 from failing to accurately drive the extension and retraction of the folding soft cylinder 27 due to the shaking of the stirring cylinder 28 when the hydraulic cylinder 280 drives the stirring cylinder to move up and down, or the horizontal stirring rod 29 from colliding with the inner wall of the absorbent liquid storage tank 201. The axial sliding can ensure that the stirring cylinder 28 can move smoothly in the vertical direction.

[0027] The upper end of the linkage lever 281 is provided with a lever block 283, and the side wall of the placement cylinder 25 is provided with a transparent observation window 251. When the hydraulic cylinder 280 drives the stirring cylinder 28 to move vertically, the stirring cylinder 28 will synchronously drive the linkage lever 281 fixed on its outer wall to move up and down. At this time, the lever block 283 will directly act on the end of the folding soft cylinder 27, accurately transmitting the displacement while driving the folding soft cylinder 27 to extend and retract.

Claims

1. A combined heat and power biogas utilization system, characterized in that, It includes a biogas digester (1), a biogas desulfurization module (2) connected to the biogas digester (1), a gas storage module (3) connected to the biogas desulfurization module (2), and a cogeneration module (4) connected to the gas storage module (3). The biogas desulfurization module (2) includes a wet desulfurization unit (20), a biogas cold dryer (21), and a dry desulfurization unit (22). The cogeneration module (4) includes a gas booster (40) connected to the gas storage module (3), a generator set (41) connected to the gas booster (40), a lithium bromide absorption chiller (42) connected to the generator set (41), and an ORC waste heat power generation unit (43). The lithium bromide absorption chiller (42) is connected to the high-temperature flue gas outlet of the generator set (41). The refrigerant outlet pipe of the lithium bromide absorption chiller (42) is connected to the temperature control jacket of the biogas digester (1) and the external living area. A flow regulating valve (44) is provided at the connection with the temperature control jacket of the biogas digester (1), and a three-way diverter valve (45) is provided at the connection with the external living area. The ORC waste heat power generation unit (43) includes an ORC evaporator (430) connected to the cylinder liner cooling water outlet of the generator set (41) and vaporizing the waste heat introduced into the generator set (41) to form high-pressure steam, an expander (431) connected to the ORC evaporator (430), and an ORC generator (432) coaxially connected to the expander (431). The cooling water outlet pipe of the ORC evaporator (430) is connected to the biogas desulfurization module (2). The low-voltage AC power output by the generator set (41) and the ORC generator (432) is rectified into high-voltage power that meets the grid standard by the ORC grid-connected inverter (433).

2. The combined heat and power biogas utilization system according to claim 1, characterized in that, After the biogas is desulfurized by the biogas desulfurization module (2), the generator set (41) uses the desulfurized and purified biogas as fuel to drive the generator through combustion, outputting low-voltage AC power and rectifying it into high-voltage power that meets the grid standards. The lithium bromide absorption chiller (42) converts the high-grade waste heat of the generator set (41) into cold energy. Part of it provides cold energy for the external load, and the other part is sent to the temperature control jacket of the biogas fermentation tank (1). The ORC waste heat power generation unit (43) supplies power to the cylinder liner of the generator set (41). The medium-grade waste heat of the cooling water is recovered and then generated by the ORC generator (432) into low-voltage AC power and rectified into low-voltage power that meets the grid standard. The low-grade waste heat generated by the ORC generator (432) provides auxiliary heating for the absorbent liquid of the wet desulfurization unit (20). The high-grade waste heat temperature of the generator set (41) is 350-500℃, the medium-grade waste heat temperature of the generator set (41) is 85-90℃, and the low-grade waste heat temperature of the ORC generator (432) is 40-55℃.

3. The combined heat and power biogas utilization system according to claim 1, characterized in that, The dry desulfurization unit (22) is composed of several dry desulfurization towers (220) connected in series with the biogas refrigerated dryer (21).

4. A combined heat and power biogas utilization system according to claim 1, characterized in that, The corrosion inhibitor addition assembly (206) includes a placement cylinder (25) that is fastened to the absorbent storage tank (201) and has an arc-shaped notch (250) at the bottom end; several spray cylinders (26) that are distributed circumferentially at the bottom end of the placement cylinder (25) and have several spray holes (260) on the inner wall; a folding soft cylinder (27) that is connected to the spray cylinders (26) one by one; a stirring cylinder (28) that is connected to the top end of the arc-shaped notch (250) through a hydraulic cylinder (280) and has a linkage lever (281) that is circumferentially connected to the folding soft cylinder (27) one by one; several horizontal stirring rods (29) that are located on the outer wall of the stirring cylinder (28) and at the bottom end of each linkage lever (281); and a one-way valve (261) is provided at the connection between the spray cylinder (26) and the placement cylinder (25).

5. A combined heat and power biogas utilization system according to claim 4, characterized in that, The bottom of the absorbent storage tank (201) and located directly below the stirring cylinder (28) is provided with an installation base cylinder (208). The upper end of the installation base cylinder (208) is provided with an annular sliding block (2080). The bottom end of the stirring cylinder (28) is provided with a sliding recess (282). The annular sliding block (2080) is slidably connected to the inner wall of the sliding recess (282).

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