Sulfur particle growth agent for biogas complex iron wet desulfurization and treatment method thereof

Abstract

The present invention discloses a sulfur particle growth agent for biogas complex iron wet desulfurization, which is composed of fatty alcohol polyoxyethylene ether, polyacrylamide, glycerol, and polysiloxane defoaming agent. The desulfurization treatment method using the above growth agent is as follows: the complex iron solution is mixed with the sulfur particle growth agent to obtain a desulfurization liquid, the desulfurization liquid is injected into the desulfurization liquid storage tank, the gas-liquid mixing pump is started to mix the desulfurization liquid and the biogas to be treated and inject them into the desulfurization chamber, the desulfurization liquid in the desulfurization chamber oxidizes the sulfur element contained in the biogas into sulfur element, and then aggregates the sulfur element to form sulfur particles, the desulfurization liquid containing sulfur particles is filtered through a filter, the desulfurization liquid is refluxed to the desulfurization liquid storage tank, the sulfur particles are collected in the filter, and the biogas after desulfurization is discharged from the exhaust pipe to the desulfurization tank. The present invention can improve the shortcomings of the prior art, rapidly increase the sulfur particles and filter them out.

Description

Technical Field

[0001] The invention relates to the technical field of biogas desulfurization, in particular to a sulfur particle growth agent for biogas complex iron wet desulfurization and a treatment method thereof. Background Art

[0002] Biogas is widely used as a renewable energy source. Since biogas produces a small amount of hydrogen sulfide during fermentation, which is highly corrosive and produces sulfur dioxide, a pollutant, after combustion, biogas needs to be desulfurized before transportation and storage. Complex iron wet desulfurization is a relatively mature desulfurization method, and its chemical reaction equation is as follows:

[0003] H2S(g)+H2O(L)→H2S(L)+H2O(L)

[0004] H2S(L)→H + (L)+ HS - (L)

[0005] HS - (L)+ 2Fe 3+ (L) → 2Fe 2+ (L) + H + (L) + S↓

[0006] 1 / 2O2(L) + H2O(L) + 2Fe 2+ (L) → 2OH - (L) + 2Fe 3+ (L)

[0007] Superposition of reaction equations:

[0008] H2S + 1 / 2O2 → H2O + S↓,

[0009] This directly converts hydrogen sulfide in the gas into elemental sulfur. The elemental sulfur particles produced by the desulfurization reaction are typically only a few microns in size. These fine particles become suspended in the desulfurization liquid. When the number of these particles is high, the biogas flows upward, producing sulfur foam that seriously impacts the normal operation of the desulfurization process. These fine particles cannot be completely removed mechanically. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a sulfur particle growth agent and a treatment method thereof for biogas complex iron wet desulfurization, which can solve the shortcomings of the existing technology, rapidly enlarge sulfur particles and filter them out.

[0011] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0012] A sulfur particle growth agent for biogas complex iron wet desulfurization is composed of fatty alcohol polyoxyethylene ether, polyacrylamide, glycerol and polysiloxane defoaming agent.

[0013] As a preference, the set mass ratio of fatty alcohol polyoxyethylene ether, polyacrylamide, glycerol, and polysiloxane defoamer in the desulfurization liquid is 21wt%: 1.5wt‰: 2wt%: 0.1wt‰

[0014] A method for treating the sulfur particle growth agent for biogas-complexed iron wet desulfurization comprises the following steps:

[0015] A desulfurization tank is provided, and a desulfurization liquid storage tank, a gas-liquid mixing pump and a desulfurization chamber are provided in the desulfurization tank. The liquid inlet end of the gas-liquid mixing pump is connected to the desulfurization liquid storage tank, and the gas inlet end of the gas-liquid mixing pump is connected to the biogas transmission pipe. Ejectors are respectively installed on the top and bottom of the desulfurization chamber, and the output end of the gas-liquid mixing pump is connected to the ejector. A reactor is installed in the middle of the desulfurization chamber, and the ejector ejects the desulfurization liquid mixed with biogas into the reactor. A filter is installed at the bottom of the desulfurization chamber, and the filter is connected to the desulfurization liquid storage tank through a reflux pipe. A liquid replenishing pipe is installed on the desulfurization liquid storage tank, and an exhaust pipe is installed on the desulfurization chamber.

[0016] The complex iron solution and the sulfur particle growth agent are mixed to obtain a desulfurization liquid, which is injected into the desulfurization liquid storage tank. The gas-liquid mixing pump is started to mix the desulfurization liquid and the biogas to be treated and inject them into the desulfurization chamber. In the desulfurization chamber, the desulfurization liquid oxidizes the sulfur element contained in the biogas into sulfur element, and then aggregates the sulfur element to form sulfur particles. The desulfurization liquid containing sulfur particles is filtered through a filter, and the desulfurization liquid is returned to the desulfurization liquid storage tank. The sulfur particles are collected in the filter, and the desulfurized biogas is discharged from the desulfurization tank through the exhaust pipe. According to the changes in the content of various substances in the desulfurization liquid in the desulfurization liquid storage tank, corresponding supplements are made through the liquid replenishing pipe to keep the content of various substances in the desulfurization liquid in the desulfurization liquid storage tank at the set value.

[0017] Preferably, the injector includes an injector bracket, on which several injector heads are evenly mounted, the liquid inlet end of the injector head is connected in parallel with an atomizer and a straight-through pipeline, the atomizer is connected to the annular outlet, a conical flare is provided at the end of the straight-through pipeline, the annular outlet and the conical flare are concentrically arranged, and the conical flare is located on the inner side of the annular outlet.

[0018] Preferably, the reactor includes a reactor bracket, a mesh plate is installed on the top of the reactor bracket, and several baffles are staggeredly installed below the mesh plate. A turntable is installed on the bottom of the reactor bracket through a slide groove, a through hole is provided in the center of the turntable, a mounting bracket is fixed in the through hole, and a guide blade is fixed on the top of the mounting bracket. The guide blade is located above the turntable, and the distance between the outer end of the guide blade and the axis of the turntable is greater than the radius of the through hole. The top surface of the turntable is provided with radial ribs, and the edge of the turntable is provided with leakage holes. The injector at the top of the desulfurization chamber sprays desulfurization liquid mixed with biogas onto the mesh plate. The desulfurization liquid mixed with biogas flows through the baffle after dispersion through the mesh plate and then drips onto the turntable. The injector at the bottom of the desulfurization chamber sprays the desulfurization liquid mixed with biogas onto the guide blade through the through hole. On the one hand, the turntable is driven to rotate by the guide blade, and at the same time, the desulfurization liquid mixed with biogas drips onto the turntable along the surface of the guide blade. The desulfurization liquid mixed with biogas produces horizontal stirring on the turntable and is finally discharged through the leakage hole.

[0019] Preferably, the cross section of the baffle is an inverted V-shape, and the top surface of the baffle is provided with guide strips inclined downward, and the guide strips are staggered.

[0020] Preferably, the filter includes a shell, a liquid inlet connected to the desulfurization chamber is provided at one end of the shell, a filter is installed obliquely downward below the liquid inlet, a recess is provided at the end of the filter away from the liquid inlet, the bottom of the shell is connected to the reflux pipe, the top of the shell is connected to the desulfurization chamber through the exhaust port, an injection pipe is installed below the filter, and the exhaust pipe is connected to the injection pipe through a pressure pump.

[0021] The beneficial effects of adopting the above technical solution are: by optimizing the composition and ratio of the growth agent and redesigning the internal structure of the desulfurization tank, the present invention can thoroughly desulfurize the biogas, and can grow sulfur particles of about 0.5 to 1 mm in size in the desulfurization liquid. The sulfur particles have good fluidity and are easy to filter and collect, and the sulfur particles will not be deposited on the surface of equipment and pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of a desulfurization tank in a specific embodiment of the present invention.

[0023] Figure 2 This is a structural diagram of an ejector in a specific embodiment of the present invention (the figure shows the ejector installed on the top of the desulfurization chamber).

[0024] Figure 3 It is a structural diagram of a reactor in a specific embodiment of the present invention.

[0025] Figure 4 It is a structural diagram of a baffle in a specific embodiment of the present invention.

[0026] Figure 5It is a structural diagram of a filter in a specific embodiment of the present invention. Implementation Method

[0027] Reference Figure 1-5 In a specific embodiment of the present invention, a sulfur particle growth agent for wet desulfurization of biogas-complexed iron is composed of fatty alcohol polyoxyethylene ether, polyacrylamide, glycerol, and polysiloxane defoaming agent. The set mass ratio of fatty alcohol polyoxyethylene ether, polyacrylamide, glycerol, and polysiloxane defoaming agent in the desulfurization liquid is 21wt%: 1.5wt‰: 2wt%: 0.1wt‰.

[0028] Fatty alcohol polyoxyethylene ether (AEO) is represented by the following general formula: RO(CH2CH2O)nH, where n represents the degree of polymerization. R is generally a saturated or unsaturated C12-C18 hydrocarbon group, which can be straight-chain or branched. n represents the number of ethylene oxide additions, or the number of oxyethylene groups in the surfactant molecule. A larger n indicates more oxygen on the hydrophilic side of the molecule, which allows for more hydrogen bonds with water and improves water solubility. Fatty alcohol polyoxyethylene ether is an important class of nonionic surfactants. The ether bonds in the molecules are not easily broken by acids or alkalis, resulting in high stability. They also offer advantages such as good water solubility, electrolyte resistance, biodegradability, and low foaming. Therefore, fatty alcohol polyoxyethylene ether is a preferred sulfur particle modifier due to its excellent effect on particle aggregation.

[0029] Polyacrylamide (PAM) is one of the most widely used water-soluble polymers. It is easy to obtain various modified products with branched or network structures through grafting or cross-linking.

[0030] In order to avoid excessive growth of sulfur particles and blockage of equipment, glycerol is used as a wetting agent to accelerate particle sedimentation.

[0031] Due to the addition of surfactants to the solution, foaming is easily generated during desulfurization operations, necessitating the use of polysiloxane defoamers. Representative polysiloxane defoaming mechanisms include the "bridging-spreading," "bridging-dewetting," and "spreading-liquid entrainment" mechanisms. The "bridging-spreading" mechanism, based on the fundamental principle that polysiloxane has relatively low tension and easily spreads on the liquid film, emphasizes the easy deformation of defoamer droplets. The "bridging-dewetting" mechanism, primarily based on the inherent hydrophobicity of polysiloxane, is more effective in defoaming polysiloxanes with higher viscosities. The "spreading-liquid entrainment" mechanism also breaks bubbles.

[0032] A method for treating the sulfur particle growth agent for biogas-complexed iron wet desulfurization comprises the following steps:

[0033] A desulfurization tank 1 is provided, in which a desulfurization liquid storage tank 2, a gas-liquid mixing pump 3 and a desulfurization chamber 4 are provided. The liquid inlet end of the gas-liquid mixing pump 3 is connected to the desulfurization liquid storage tank 2, and the gas inlet end of the gas-liquid mixing pump 3 is connected to the biogas delivery pipe 5. Ejectors 6 are respectively installed on the top and bottom of the desulfurization chamber 4, and the output end of the gas-liquid mixing pump 3 is connected to the ejector 6. A reactor 7 is installed in the middle of the desulfurization chamber 4. The ejector 6 ejects the desulfurization liquid mixed with biogas into the reactor 7. A filter 8 is installed at the bottom of the desulfurization chamber 4, and the filter 8 is connected to the desulfurization liquid storage tank 2 through a reflux pipe 9. A liquid replenishing pipe 10 is installed on the desulfurization liquid storage tank 2, and an exhaust pipe 11 is installed on the desulfurization chamber 4;

[0034] The complex iron solution and the sulfur particle growth agent are mixed to obtain a desulfurization liquid, which is injected into the desulfurization liquid storage tank 2. The gas-liquid mixing pump 3 is started to mix the desulfurization liquid and the biogas to be treated and inject them into the desulfurization chamber 4. In the desulfurization chamber 4, the desulfurization liquid oxidizes the sulfur element contained in the biogas into sulfur element, and then aggregates the sulfur element to form sulfur particles. The desulfurization liquid containing sulfur particles is filtered through the filter 8, and the desulfurization liquid is refluxed to the desulfurization liquid storage tank 2. The sulfur particles are collected in the filter 8, and the desulfurized biogas is discharged from the desulfurization tank 1 through the exhaust pipe 11. According to the changes in the content of each substance in the desulfurization liquid in the desulfurization liquid storage tank 2, corresponding supplements are made through the liquid replenishing pipe 10 to keep the content of each substance in the desulfurization liquid in the desulfurization liquid storage tank 2 at the set value.

[0035] The injector 6 includes an injector bracket 12, on which several injector heads 13 are evenly mounted. The liquid inlet end of the injector head 13 is connected in parallel with an atomizer 14 and a straight-through pipe 15. The atomizer 14 is connected to an annular outlet 16. A conical flare 17 is provided at the end of the straight-through pipe 15. The annular outlet 16 and the conical flare 17 are concentrically arranged, and the conical flare 17 is located on the inner side of the annular outlet 16. The reactor 7 includes a reactor bracket 18, a mesh plate 19 is installed on the top of the reactor bracket 18, and a number of baffles 20 are staggeredly installed below the mesh plate 19. A turntable 21 is installed at the bottom of the reactor bracket 18 through a slide groove. A through hole 22 is provided in the center of the turntable 21. A mounting frame 23 is fixed in the through hole 22. A guide vane 24 is fixed on the top of the mounting frame 23. The guide vane 24 is located above the turntable 21. The distance between the outer end of the guide vane 24 and the axis of the turntable 21 is greater than the radius of the through hole 22. The top surface of the turntable 21 is provided with radial ribs 25, and the edge of the turntable 21 is provided with a drainage hole. 26. The ejector 6 at the top of the desulfurization chamber 4 sprays desulfurization liquid mixed with biogas onto the mesh plate 19. The desulfurization liquid mixed with biogas is dispersed by the mesh plate, flows through the baffle 20, and then drips onto the turntable 21. The ejector 6 at the bottom of the desulfurization chamber 4 sprays the desulfurization liquid mixed with biogas onto the guide vanes 24 through the through holes 22. On the one hand, the turntable 21 is driven to rotate by the guide vanes 24. At the same time, the desulfurization liquid mixed with biogas drips onto the turntable 21 along the surface of the guide vanes 24. The desulfurization liquid mixed with biogas generates horizontal agitation on the turntable 21 and is finally discharged through the drain hole 26. The cross-section of the baffle 20 is an inverted V-shape. The top surface of the baffle 20 is provided with guide bars 27 inclined downward, and the guide bars 27 are staggered. The straight-through pipe 15 is used to provide high-velocity mixed liquid injection. Under the guidance of the conical flare 17, the high-velocity mixed liquid carries the external atomized mixed liquid and is evenly sprayed on the mesh plate 19, achieving full contact and fusion of the biogas and desulfurization liquid in the mixed liquid. The mixed liquid drips from the mesh plate 9 onto the baffle 20, and flows back and forth on the baffle 20 many times, extending the contact time between the biogas and the desulfurization liquid. The ejector 6 at the bottom uses the high-velocity mixed liquid to push the guide vane 24 to achieve the rotation of the turntable 21. The mixed liquid is stirred horizontally on the turntable 21, further improving the contact effect between the biogas and the desulfurization liquid in the mixed liquid.

[0036] The filter 8 includes a housing 28, one end of which is provided with a liquid inlet 29 connected to the desulfurization chamber 4. A filter screen 30 is installed obliquely downward below the liquid inlet 29. A recessed portion 31 is provided at the end of the filter screen 30 away from the liquid inlet 29. The bottom of the housing 28 is connected to the reflux pipe 9, and the top of the housing 28 is connected to the desulfurization chamber 4 via an exhaust port 32. An air jet 33 is installed below the filter screen 30, and the exhaust pipe 11 is connected to the air jet 33 via a pressure pump 34. Due to the decrease in the flow rate of the mixed liquid undergoing the desulfurization reaction through the reactor 7, sulfur particles are easily attached to the surface of the filter screen 30 when filtering through the filter screen 30, reducing the permeability of the filter screen 30. To solve this problem, the present invention installs the filter screen 30 at an angle and uses the desulfurized biogas to purge the filter screen 30, so that the filtered sulfur particles are quickly gathered in the recessed portion 31, maintaining the normal filtration permeability of the filter screen 30.

[0037] One end of the exhaust port 32 connected to the desulfurization chamber 4 extends into the turntable 21, and the biogas flow ejected from the exhaust port 32 is used to aerate and stir the mixed liquid in the turntable 21, thereby further improving the desulfurization effect of the mixed liquid without adding additional components.

[0038] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for treating a sulfur particle growth agent for biogas complex iron wet desulfurization, characterized in that The following steps are involved: A desulfurization tank (1) is provided, wherein a desulfurization liquid storage tank (2), a gas-liquid mixing pump (3) and a desulfurization chamber (4) are provided in the desulfurization tank (1), the liquid inlet end of the gas-liquid mixing pump (3) is connected to the desulfurization liquid storage tank (2), the gas inlet end of the gas-liquid mixing pump (3) is connected to the biogas delivery pipe (5), ejectors (6) are respectively installed at the top and bottom of the desulfurization chamber (4), the output end of the gas-liquid mixing pump (3) is connected to the ejector (6), a reactor (7) is installed in the middle of the desulfurization chamber (4), the ejector (6) ejects the desulfurization liquid mixed with biogas into the reactor (7), a filter (8) is installed at the bottom of the desulfurization chamber (4), the filter (8) is connected to the desulfurization liquid storage tank (2) through a reflux pipe (9), a liquid replenishing pipe (10) is installed on the desulfurization liquid storage tank (2), and an exhaust pipe (11) is installed on the desulfurization chamber (4); The complex iron solution and the sulfur particle growth agent are mixed to obtain a desulfurization liquid, and the desulfurization liquid is injected into the desulfurization liquid storage tank (2). The gas-liquid mixing pump (3) is started to mix the desulfurization liquid and the biogas to be treated and inject the desulfurization liquid into the desulfurization chamber (4). In the desulfurization chamber (4), the desulfurization liquid oxidizes the sulfur element contained in the biogas into sulfur element, and then aggregates the sulfur element to form sulfur particles. The desulfurization liquid containing the sulfur particles is filtered through the filter (8), and the desulfurization liquid is returned to the desulfurization liquid storage tank (2). The sulfur particles are collected in the filter (8), and the desulfurized biogas is discharged from the desulfurization tank (1) through the exhaust pipe (11); according to the change of the content of each substance in the desulfurization liquid in the desulfurization liquid storage tank (2), corresponding replenishment is performed through the liquid replenishing pipe (10), so that the content of each substance in the desulfurization liquid in the desulfurization liquid storage tank (2) is maintained at a set value; The injector (6) includes an injector bracket (12), a plurality of injector heads (13) are evenly mounted on the injector bracket (12), a liquid inlet end of the injector head (13) is connected in parallel to an atomizer (14) and a straight-through pipe (15), the atomizer (14) is connected to an annular outlet (16), a conical flare (17) is provided at the end of the straight-through pipe (15), the annular outlet (16) and the conical flare (17) are concentrically arranged, and the conical flare (17) is located on the inner side of the annular outlet (16); The reactor (7) includes a reactor bracket (18), a mesh plate (19) is installed on the top of the reactor bracket (18), and a plurality of baffles (20) are staggeredly installed below the mesh plate (19). A turntable (21) is installed at the bottom of the reactor bracket (18) through a slide groove. A through hole (22) is provided at the center of the turntable (21), a mounting frame (23) is fixed in the through hole (22), and a guide vane (24) is fixed on the top of the mounting frame (23). The guide vane (24) is located above the turntable (21), and the distance between the outer end of the guide vane (24) and the axis of the turntable (21) is greater than the radius of the through hole (22). The top surface of the turntable (21) is provided with radial ribs (25). The edge of the turntable (21) A leakage hole (26) is provided on the edge of the desulfurization chamber (4). The ejector (6) located at the top of the desulfurization chamber (4) ejects the desulfurization liquid mixed with biogas onto the mesh plate (19). The desulfurization liquid mixed with biogas is dispersed by the mesh plate and flows through the baffle (20), and then drips onto the turntable (21). The ejector (6) located at the bottom of the desulfurization chamber (4) ejects the desulfurization liquid mixed with biogas onto the guide vane (24) through the through hole (22). On the one hand, the turntable (21) is driven to rotate by the guide vane (24), and at the same time, the desulfurization liquid mixed with biogas drips onto the turntable (21) along the surface of the guide vane (24). The desulfurization liquid mixed with biogas generates horizontal agitation on the turntable (21) and is finally discharged through the leakage hole (26).

2. The method for treating a sulfur particle growth agent for biogas-complexed iron wet desulfurization according to claim 1, characterized in that: The cross section of the baffle (20) is an inverted V-shape, and the top surface of the baffle (20) is provided with guide strips (27) inclined downward, and the guide strips (27) are staggered.

3. The method for treating a sulfur particle growth agent for biogas-complexed iron wet desulfurization according to claim 1, characterized in that: The filter (8) includes a shell (28), one end of which is provided with a liquid inlet (29) connected to the desulfurization chamber (4), a filter screen (30) is installed obliquely downward below the liquid inlet (29), and a recessed portion (31) is provided at one end of the filter screen (30) away from the liquid inlet (29). The bottom of the shell (28) is connected to the return pipe (9), and the top of the shell (28) is connected to the desulfurization chamber (4) through the exhaust port (32). An air jet pipe (33) is installed below the filter screen (30), and the exhaust pipe (11) is connected to the air jet pipe (33) through a pressure pump (34).

4. The method for treating a sulfur particle growth agent for biogas-complexed iron wet desulfurization according to claim 1, characterized in that: The sulfur particle growth agent consists of fatty alcohol polyoxyethylene ether, polyacrylamide, glycerol and polysiloxane defoaming agent.

5. The method for treating a sulfur particle growth agent for biogas-complexed iron wet desulfurization according to claim 4, characterized in that: The set mass ratio of the fatty alcohol polyoxyethylene ether, polyacrylamide, glycerol, and polysiloxane defoaming agent in the desulfurization liquid is 21wt%:1.5wt‰:2wt%:0.1wt‰.

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