Device and method for biological desulfurization of sulfur-containing gas

Abstract

The invention relates to the technical field of sulfur-containing gas treatment, in particular to a sulfur-containing gas biological desulfurization device and method.The device comprises an absorption unit used for absorbing sulfide in sulfur-containing gas to obtain desulfurized gas and sulfur-containing pregnant solution; the biological oxidation reaction unit is used for performing biological oxidation on the sulfur-containing pregnant solution; and the pressure control unit is arranged between communicating pipelines of the absorption unit and the biological oxidation reaction unit and is used for reducing the pressure of the sulfur-containing pregnant solution and stabilizing the pressure. According to the biological desulfurization device, the liquid level of the liquid seal slug at the bottom of the absorption tower can be stably controlled, the risk that high-pressure sulfur-containing gas or sulfur-containing gas with great pressure fluctuation in the absorption tower leaks to the atmosphere end through a connecting pipeline and a bioreactor is avoided, and the desulfurization efficiency is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of sulfur-containing gas treatment technology, and more specifically to an apparatus and method for biological desulfurization of sulfur-containing gases. Background Technology

[0002] With the continuous growth of global energy demand, the demand for natural gas, as a clean and efficient energy source, is also increasing. However, natural gas contains harmful substances such as hydrogen sulfide, which can pollute the environment, corrode equipment, and seriously affect human health. Therefore, desulfurization is a necessary step in the extraction, transportation, and use of natural gas.

[0003] Natural gas desulfurization methods include physical, chemical, and biological methods. Physical methods primarily separate hydrogen sulfide from natural gas through physical adsorption and absorption. The advantages of this method are its simplicity and speed, but the adsorbent requires periodic regeneration, resulting in high operating costs. Chemical methods mainly convert hydrogen sulfide into other harmless substances, such as sulfur, through chemical reactions. The advantages of this method are high desulfurization efficiency, but it requires large amounts of chemical reagents, leading to high costs. All physical and chemical natural gas desulfurization technologies are complex, the production process is difficult to control, operating costs are high, and secondary pollution may occur.

[0004] Existing natural gas desulfurization processes mainly include the alkanolamine method, dry desulfurization, low-temperature methanol method, and complexed iron method.

[0005] The amine method is currently the most widely used method for natural gas desulfurization. This method primarily removes hydrogen sulfide through the chemical absorption of amine solvents. Commonly used amine solvents include monoethanolamine, diethanolamine, diisopropanolamine, and methyldiethanolamine. While the process is relatively mature, it still suffers from problems such as bulky equipment, high investment costs, regeneration issues, and environmental pollution. The biggest problem is the regeneration of the absorbent. Currently, the main regeneration method is high-temperature vacuum distillation, which is energy-intensive, requires significant investment, and has a low regeneration recovery rate.

[0006] Dry desulfurization removes hydrogen sulfide from gas by passing it through a bed of solid adsorbents. Commonly used solid adsorbents include sponge iron, activated carbon, alumina, zeolite, and molecular sieves. It is primarily used to treat gases containing trace amounts of hydrogen sulfide. This method is an intermittent operation and suffers from problems such as bulky equipment, high investment costs, low throughput, difficulty in adsorbent regeneration, and significant development challenges.

[0007] The low-temperature methanol washing method utilizes methanol's excellent solubility for acidic gases at low temperatures to remove acidic gases from the feed gas. Low-temperature methanol exhibits good heat and mass transfer properties, high selectivity, high purification efficiency, low corrosivity, and low cost, saving on investment costs. The solvent does not oxidize or degrade, possesses excellent chemical and thermal stability, and does not foam during absorption, allowing for stable production. However, methanol is toxic, requiring an additional refrigeration system, which increases the difficulty of operation and maintenance. Furthermore, this process is based on foreign technology, necessitating the purchase of patented software packages, resulting in a significant initial investment.

[0008] The complexed iron method uses high-valence iron ions to convert H2S into sulfur, which is then oxidized to regenerate high-valence iron ions for the recycling of hydrogen sulfide. Its advantages include high desulfurization rate, short process, simple equipment, and mature technology. Disadvantages include high investment, large land area, high operating costs, and the production of hazardous waste.

[0009] Biological desulfurization is an emerging method that primarily utilizes the metabolism of microorganisms to convert hydrogen sulfide into elemental sulfur or other harmless substances. This method offers advantages such as low cost and high adaptability. Currently, natural gas biological desulfurization technology is still in the laboratory exploration stage in my country, and many challenges remain to be overcome before it can be applied to industrial sites. Therefore, developing a low-cost, efficient, and adaptable natural gas desulfurization process is a pressing issue in this field. Summary of the Invention

[0010] To overcome the risks of sulfur-containing gas leakage during the regeneration process of the bioreactor (which is an atmospheric pressure device and the hydrogen sulfide absorption tower is a pressurized device) in existing industrial desulfurization technologies, where the pressure of sulfur-containing gas (e.g., natural gas) is high or unstable, and the bioreactor is an atmospheric pressure device while the hydrogen sulfide absorption tower is a pressurized device, this invention provides a device and method for biological desulfurization of sulfur-containing gas. The pressure control unit in this biological desulfurization device can maintain stable control of the liquid level of the liquid seal plug at the bottom of the absorption tower during the biological desulfurization process, avoiding the risk of high-pressure sulfur-containing gas or sulfur-containing gas with large pressure fluctuations leaking to the atmosphere through connecting pipelines and the bioreactor, and effectively improving desulfurization efficiency.

[0011] To achieve the above objectives, a first aspect of the present invention provides an apparatus for biological desulfurization of sulfur-containing gases, the apparatus comprising:

[0012] The absorption unit is used to absorb sulfides in sulfur-containing gases to obtain desulfurized gases and sulfur-rich solutions.

[0013] A bio-oxidation reaction unit is used to bio-oxidize the sulfur-rich solution;

[0014] A pressure control unit is located between the absorption unit and the bio-oxidation reaction unit in the connecting pipeline, and is used to reduce the pressure of the sulfur-rich solution and stabilize the pressure.

[0015] A second aspect of the present invention provides a method for biological desulfurization of sulfur-containing gases, the method employing the biological desulfurization device described in the present invention, the method comprising:

[0016] After the sulfur-containing gas comes into contact with the alkaline solution in the absorption unit, desulfurized gas and sulfur-rich solution are obtained; the sulfur-rich solution is depressurized to 0.1-0.3 MPa and then enters the bio-oxidation reaction unit for bio-oxidation.

[0017] Through the above technical solution, the biological desulfurization device of the present invention can achieve stable control of the liquid level of the liquid seal sluice at the bottom of the absorption tower, avoiding the risk of high-pressure sulfur-containing gas or sulfur-containing gas with large pressure fluctuations leaking to the atmosphere through connecting pipelines and bioreactor in the absorption tower, and effectively improving the desulfurization efficiency; and according to the preferred embodiment of the present invention, the desulfurization device is also equipped with an electric valve to control the opening and closing of the sulfur-rich liquid according to the sluice height, further reducing the risk of high-pressure sulfur-containing gas leaking to the atmosphere in the event of large pressure fluctuations of sulfur-containing gas or sudden power outage.

[0018] On the other hand, according to a preferred embodiment of the present invention, the biological desulfurization device of the present invention can realize automatic control of reaction conditions, automatic dosing, and automatic sludge discharge in the biological desulfurization process, maintain a high activity concentration of desulfurization bacteria, and achieve efficient and stable operation of the biological desulfurization process for high-pressure sulfur-containing gas or sulfur-containing gas with large pressure fluctuations; it can also avoid pipeline freezing and blockage in winter, reduce the difficulty of device operation and management and the intensity of manual labor.

[0019] The biological desulfurization method described in this invention can adapt to the desulfurization of sulfur-containing gases with various hydrogen sulfide concentrations and potential sulfur contents, purifying the sulfur-containing gases to a hydrogen sulfide content of less than 10 mg / m³. 3 It has high desulfurization efficiency; and the process is simple and the reaction conditions are mild, with advantages such as low cost, environmental protection and good operational stability.

[0020] Compared with existing technologies, this technical solution mainly solves the following problems:

[0021] 1) The high operating costs of physical and chemical desulfurization technologies;

[0022] 2) Existing physical and chemical desulfurization technologies may cause secondary pollution.

[0023] 3) The desulfurization process is complex, the reaction conditions are difficult to control, and the operation and management are challenging.

[0024] 4) Other problems in industrial applications: such as the oil carried in natural gas affecting microbial activity and reducing desulfurization efficiency and effect; the bioreactor is an atmospheric pressure device, while the hydrogen sulfide absorption tower is a pressurized device, and there is a risk of sulfur-containing natural gas leakage during the regeneration process of the bioreactor with sulfide-rich liquid.

[0025] 5) After wet processing, the natural gas has a high water content. Condensate accumulates in low-lying areas of the pipeline, causing liquid blockage. In winter, when the temperature is low, it is even more likely to cause pipeline freezing blockage.

[0026] Biological Preservation

[0027] Attached Figure Description

[0028] Figure 1 This is a process flow diagram of an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the gas washing process of the gas washing tower according to an embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures

[0031] 1-Scrubbing tower; 2-Absorption tower; 3-Gas-liquid separator; 5-Bioreactor; 6-Aeration blower; 7-First transfer pump; 8-Settling tank; 9-First heat exchanger; 10-Second heat exchanger; 11-Aeration distributor; 12-Nutrient dosing device; 13-Alkali dosing device; 14-Second transfer pump; 15-Centrifuge; 16-Waste liquid tank; 17-Pressure reducing valve; 18-Electric regulating valve; 19-Solenoid valve. Detailed Implementation

[0032] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" generally refer to the direction shown in the accompanying drawings or to the relative positional relationships of components in a vertical, perpendicular, or gravitational direction; "inner" and "outer" generally refer to radial inward or outward relative to the center of a circle, or inner and outer sides of a cavity relative to the cavity itself. In this invention, "upstream" and "downstream" refer to upstream and downstream along the material flow direction. In this invention, "rich solution" and "poor solution" refer to the relative content of sulfides in the alkaline solution.

[0034] The first aspect of the present invention provides an apparatus for biological desulfurization of sulfur-containing gases, the apparatus comprising:

[0035] The absorption unit is used to absorb sulfides in sulfur-containing gases to obtain desulfurized gases and sulfur-rich solutions.

[0036] The bio-oxidation reaction unit is used to bio-oxidize sulfur-rich liquid.

[0037] A pressure control unit, located between the absorption unit and the bio-oxidation reaction unit, is used to reduce and stabilize the pressure of the sulfur-rich liquid. This invention's biological desulfurization device can effectively reduce the hydrogen sulfide content in sulfur-containing gases, minimizing environmental pollution and equipment corrosion. Furthermore, this biological desulfurization device enables stable control of the liquid level in the liquid seal sluice at the bottom of the absorption tower, preventing the risk of high-pressure or fluctuating sulfur-containing gas leaking into the atmosphere through connecting pipelines and the bioreactor, and effectively improving desulfurization efficiency.

[0038] In this invention, the absorption unit includes an absorption tower 2 and a liquid sealing device. The liquid sealing device is used to form a liquid sealing plug at the bottom of the absorption tower 2 to prevent sulfur-containing gas from leaking from the absorption tower 2 into the bioreactor 5.

[0039] According to a preferred embodiment of the present invention, a packing layer is provided inside the absorption tower 2 to improve the gas-liquid mass transfer efficiency and promote the absorption of sulfides in sulfur-containing gases.

[0040] In this invention, the pressure control unit includes: a pressure reducing valve 17 for reducing the pressure of sulfur-rich liquid; and an electric regulating valve 18 located downstream of the pressure reducing valve for regulating the flow rate of the sulfur-rich liquid and the height of the liquid seal sluice; thereby achieving stable control of the liquid level of the liquid seal sluice at the bottom of the absorption tower.

[0041] In this invention, the bio-oxidation reaction unit includes a bioreactor 5, which is used to bio-oxidize sulfur-rich liquid to obtain a slurry containing elemental sulfur.

[0042] According to a preferred embodiment of the present invention, the bioreactor 5 is a fluidized bed bioreactor.

[0043] In this invention, the bio-oxidation reaction unit includes an elemental sulfur separation system, which is used to separate elemental sulfur from a slurry containing elemental sulfur to obtain elemental sulfur and regenerated alkali solution.

[0044] According to a preferred embodiment of the present invention, the bioreactor 5 is a dual-chamber airlift reactor, with the two chambers connected by a slot at the bottom of a partition.

[0045] According to a preferred embodiment of the present invention, an aeration unit is provided at the bottom of the bioreactor 5 to uniformly distribute the aeration volume within the bioreactor 5 and effectively control the generation of the byproduct sulfate.

[0046] According to a preferred embodiment of the present invention, the aeration unit includes an aeration blower 6 and an aeration distributor 11, wherein the aeration distributor 11 is connected to the aeration blower 6 via a pipe.

[0047] In this invention, the bioreactor 5 further includes a nutrient dosing device 12 and an alkali dosing device 13. The nutrient dosing device 12 is used to feed nutrients into the bioreactor 5; the alkali dosing device 13 is used to feed fresh alkali solution into the bioreactor 5. Preferably, the nutrient dosing device 12 and the alkali dosing device 13 are each connected to the top of the bioreactor 5 via pipes.

[0048] In this invention, the nutrient is used to provide nutrition for the biooxidizing bacteria in bioreactor 5. The type of nutrient can be adjusted according to the actual needs based on the type of biooxidizing bacteria, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the nutrient is selected from one or more of glucose, KH2PO4, NH4Cl, NaNO3, and trace elements (Mg, Mn, Na, Fe, Co, Ca, Ni, Zn).

[0049] According to a preferred embodiment of the present invention, the elemental sulfur separation system includes a settling tank 8, optionally a second transfer pump 14 and a centrifuge 15. The bottom of the settling tank 8 is connected in sequence to the optional second transfer pump 14 and centrifuge 15 via a pipeline. The settling tank 8 is used to settle the slurry containing elemental sulfur to obtain elemental sulfur slurry and regenerated alkali solution. The second transfer pump 14 is used to transport the elemental sulfur slurry to the downstream centrifuge 15. The centrifuge 15 is used to perform solid-liquid separation of the elemental sulfur slurry to obtain elemental sulfur.

[0050] According to one embodiment of the present invention, the absorption unit further includes a gas scrubbing tower 1, which is disposed upstream of the absorption tower 2 and is used to remove non-gaseous substances from the sulfur-containing gas. Preferably, the top of the gas scrubbing tower 1 is connected to the lower part of the absorption tower 2 via a pipeline.

[0051] According to one embodiment of the present invention, the biological desulfurization device further includes a first automatic control unit for monitoring and controlling the liquid seal slug.

[0052] According to a preferred embodiment of the present invention, the first automatic control unit includes: a level gauge disposed at the bottom of the absorption tower for monitoring the height of the liquid seal sluice.

[0053] According to a preferred embodiment of the present invention, the first automatic control unit includes: a solenoid valve 19 connected in series downstream of the electric regulating valve 18, which controls the flow of sulfur-rich liquid by opening and closing, thereby further reducing the risk of high-pressure sulfur-rich gas leaking to the atmosphere in the event of large fluctuations in sulfur-containing gas pressure or sudden power outage.

[0054] According to one embodiment of the present invention, the biological desulfurization device further includes a second automatic control unit for monitoring and controlling the biological oxidation reaction unit.

[0055] According to one embodiment of the present invention, the second automatic control unit includes a thermometer, a flow meter, a level gauge, a pH meter, an ORP meter, a sludge concentration meter, a dissolved oxygen meter, and a conductivity meter disposed within the bioreactor 5.

[0056] According to one embodiment of the present invention, the second automatic control unit includes a temperature control unit for controlling the reaction temperature within the bioreactor 5.

[0057] In this invention, the temperature control unit can be installed inside the bioreactor 5, for example, by installing a heat exchange coil to control the temperature of the desulfurization alkaline solution.

[0058] In this invention, the temperature control unit can also be set outside the bioreactor 5 to exchange heat with the material entering the bioreactor 5, or to circulate the material inside the bioreactor 5 back to the bioreactor 5 after heat exchange with an external heat exchanger.

[0059] According to one embodiment of the present invention, the temperature control unit includes a first heat exchange device 9, which is used to circulate the slurry in the bioreactor 5 back to the bioreactor 5 after heat exchange with an external heat exchanger.

[0060] According to one embodiment of the present invention, the temperature control unit includes a second heat exchange device 10, which is disposed between the pressure control unit and the bioreactor 5 to exchange heat with the sulfur-rich liquid in order to control the temperature inside the bioreactor.

[0061] In this invention, solid substances such as sulfur-oxidizing bacteria and sulfur present in the slurry containing elemental sulfur in the bioreactor 5 are introduced into the absorption tower 2 through a circulation section, which can promote the absorption of hydrogen sulfide by the absorption tower 2. According to one embodiment of the invention, the biological desulfurization device further includes a first transfer pump 7, which is used to circulate the slurry containing elemental sulfur in the bioreactor 5 to the absorption tower 2.

[0062] According to one embodiment of the present invention, the biological desulfurization device further includes a gas-liquid separator 3 for gas-liquid separation of the desulfurized gas output from the absorption tower 2. Preferably, it is connected to the top of the absorption tower 2 via a pipeline.

[0063] According to one embodiment of the present invention, the apparatus for biological desulfurization of sulfur-containing gas includes: a gas scrubbing tower 1, an absorption tower 2, and a bioreactor 5 connected in sequence by pipelines;

[0064] A pressure reducing valve 17, an electric regulating valve 18, and a solenoid valve 19 are sequentially installed between the pipes connecting the absorption tower 2 and the bioreactor 5.

[0065] The absorption tower 2 is equipped with a liquid sealing device to form a liquid sealing block at the bottom of the absorption tower 2;

[0066] The bioreactor 5 and the absorption tower 2 are equipped with a first transfer pump 7, which is used to circulate the slurry containing elemental sulfur in the bioreactor 5 to the absorption tower 2.

[0067] Gas-liquid separator 3 is used to separate the desulfurized gas output from absorption tower 2 into gas and liquid components.

[0068] The elemental sulfur separation system is used to separate elemental sulfur from slurry containing elemental sulfur to obtain elemental sulfur and regenerated alkali solution.

[0069] Preferably, the biological desulfurization device for sulfur-containing gases further includes:

[0070] The first heat exchange device 9 is used to circulate the slurry in the bioreactor 5 back to the bioreactor 5 after external heat exchange.

[0071] The second heat exchange device 10 is disposed between the solenoid valve 19 and the bioreactor 5;

[0072] Aeration distributor 11 is located at the bottom of bioreactor 5;

[0073] The air aeration blower 6 is connected to the aeration distributor 11 via a pipe;

[0074] The nutrient dosing device 12 and the alkali dosing device 13 are used to feed nutrients into the bioreactor 5; the alkali dosing device 12 is used to feed fresh alkali into the bioreactor 5.

[0075] According to one embodiment of the present invention, the elemental sulfur separation system includes a settling tank 8 disposed downstream of the bioreactor 5, optionally a second transfer pump 14 and a centrifuge 15. The settling tank 8 is used to settle the slurry containing elemental sulfur to obtain elemental sulfur slurry and regenerated alkali solution; the second transfer pump 14 is used to transport the elemental sulfur slurry to the downstream centrifuge 15; the centrifuge 15 is used to perform solid-liquid separation of the elemental sulfur slurry to obtain elemental sulfur.

[0076] According to one embodiment of the present invention, such as Figure 1 As shown, the biological desulfurization device for sulfur-containing gases includes: a gas scrubbing tower 1, an absorption tower 2, and a gas-liquid separator 3. The lower part of the gas scrubbing tower 1 and the absorption tower 2 are connected by a pipeline, and the gas outlet pipeline at the top of the absorption tower 2 is connected to the gas-liquid separator 3.

[0077] The bottom of the absorption tower 2 is connected to the bioreactor 5 via a series of pressure reducing valve 17, electric regulating valve 18, solenoid valve 19, and second heat exchange device 10.

[0078] The lower part of the bioreactor 5 is discharged through the first transfer pump 7, which is connected to the settling tank 8, the first heat exchange device 9 and the absorption tower 2 through pipelines respectively.

[0079] The bottom of the bioreactor 5 is equipped with an aeration distributor 11, which is connected to the air aeration blower 6 through a pipe. The top of the bioreactor 5 is connected to the nutrient dosing device 12 and the alkali dosing device 13 through pipes respectively. The bottom of the settling tank 8 is connected to the second transfer pump 14 and the centrifuge 15 in sequence through pipes. The first heat exchange device 9 is a cooling tower, and the second heat exchange device 10 is a heater.

[0080] A second aspect of the present invention provides a method for biological desulfurization of sulfur-containing gases, the method employing the biological desulfurization device of the present invention, the method comprising:

[0081] After the sulfur-containing gas comes into contact with the alkaline solution in the absorption unit, desulfurized gas and sulfur-rich solution are obtained. The sulfur-rich solution is then depressurized to 0.1-0.3 MPa and enters the bio-oxidation reaction unit for bio-oxidation. This invention's method for biological desulfurization of sulfur-containing gas is adaptable to desulfurization of sulfur-containing gases with varying hydrogen sulfide concentrations and potential sulfur content, purifying the gas to a hydrogen sulfide content of less than 10 mg / m³. 3 The desulfurization efficiency is high. The biological desulfurization device of the present invention can achieve stable control of the liquid level of the liquid seal plug at the bottom of the absorption tower, avoiding the risk of high-pressure sulfur-containing gas or sulfur-containing gas with large pressure fluctuations leaking to the atmosphere through the connecting pipeline and bioreactor in the absorption tower, and effectively improving the desulfurization efficiency.

[0082] According to a preferred embodiment of the present invention, the biological desulfurization method includes: sulfur-containing gas is contacted with a washing medium in a gas scrubbing tower 1 to remove non-gaseous substances from the sulfur-containing gas; the gas enters an absorption tower 2 and is contacted with an alkaline solution to obtain desulfurized gas and sulfur-rich liquid; the sulfur-rich liquid is depressurized to 0.1-0.3 MPa and then enters a bioreactor 5 for biological oxidation.

[0083] In this invention, the range of types of washing media is relatively wide. According to a preferred embodiment of this invention, the washing media of the air scrubbing tower is clean water.

[0084] In this invention, the location where the sulfur-containing gas enters the gas scrubbing tower 1 can be selected from a wide range. According to a preferred embodiment of this invention, the sulfur-containing gas inlet pipe is submerged 10-20 cm below the liquid surface.

[0085] In this invention, the range of non-gaseous substances in the sulfur-containing gas is relatively wide, such as oil, water, and solid impurities.

[0086] According to a preferred embodiment of the present invention, the absorption tower 2 is a countercurrent contact type, in which sulfur-containing gas enters from the lower part of the absorption tower 2 and reacts with the alkaline solution sprayed from the top of the tower.

[0087] According to a preferred embodiment of the present invention, the biological desulfurization method further includes: the desulfurized gas is dehydrated by a gas-liquid separator 3 to obtain dehydrated gas.

[0088] According to a preferred embodiment of the present invention, the biological desulfurization method further includes: aerating the bioreactor 5 through an aeration unit, wherein in an oxygen-containing environment, sulfur-oxidizing bacteria convert sulfides in the alkaline solution into elemental sulfur, thereby simultaneously regenerating the alkaline solution.

[0089] According to a preferred embodiment of the present invention, the biological desulfurization method further includes: separating the slurry containing elemental sulfur obtained by biological oxidation to obtain elemental sulfur and regenerated alkali solution.

[0090] According to a preferred embodiment of the present invention, when the sludge concentration in the slurry containing elemental sulfur in the bioreactor 5 is high, which is not conducive to the circulation of the slurry containing elemental sulfur to the absorption tower 2 and the bioreactor 5 for biological oxidation, the slurry containing elemental sulfur is separated.

[0091] In this invention, the range of bacterial species that can be selected for bio-oxidation is relatively wide. According to a preferred embodiment of this invention, bio-oxidation uses a compound desulfurizing agent, preferably one or more of alkali-resistant sulfur-oxidizing bacteria.

[0092] According to a preferred embodiment of the present invention, the alkali-tolerant sulfur-oxidizing bacteria for bio-oxidation are selected from one or more of Pseudomonas, Aristolochic acid bacillus, Bacillus geosporus, sulfur-oxidizing bacteria, thioalkali-vibrio, and denitrifying thiobacillus; more preferably, they are one or more of Pseudomonas, Aristolochic acid bacillus, and Bacillus geosporus.

[0093] According to a preferred embodiment of the present invention, the Pseudomonas sp. includes Pseudomonas strain TD-04, which is deposited at the China General Microbiological Culture Collection Center with accession number CGMCC NO29843.

[0094] According to a preferred embodiment of the present invention, the Ochrobactrum sp. includes Ochrobactrum strain TD-05, which is deposited at the China General Microbiological Culture Collection Center with accession number CGMCC NO29844.

[0095] According to a preferred embodiment of the present invention, the Geobacillus toebii includes Geobacillus toebii strain JSHD-4, which is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC NO 7273.

[0096] In this invention, the concentration range of the bacterial strains in the compound desulfurizing agent is relatively wide. According to a preferred embodiment of this invention, the pre-fermentation concentration of the combined strains TD-04, TD-05, and JSHD-4 is greater than 1.0 × 10⁻⁶. 8 Industrial fermentation broth at cfu / mL.

[0097] In this invention, the volume ratio of the fermentation broth of each strain in the compound desulfurizing agent can be selected within a wide range. According to a preferred embodiment of this invention, the volume ratio of the fermentation broth of strains TD-04 and TD-05 in the compound desulfurizing agent is 1.0-1.3:0.9-1.2.

[0098] In this invention, the volume ratio of the fermentation broth of each strain in the compound desulfurizing agent can be selected within a wide range. According to a preferred embodiment of this invention, the volume ratio of the fermentation broth of strains TD-04 and JSHD-4 in the compound desulfurizing agent is 1.0-1.3:0.5-1.0.

[0099] In this invention, the volume ratio of the fermentation broth of each strain in the compound desulfurizing agent can be selected within a wide range. According to a preferred embodiment of this invention, the volume ratio of the fermentation broth of TD-05 and JSHD-4 in the compound desulfurizing agent is 0.9-1.2:0.5-1.0.

[0100] The composite desulfurizing agent described in this invention has strong adaptability, can carry out biological oxidation within a wide temperature range (10-45℃), withstands high-temperature shocks, and has a stable desulfurization effect, maintaining the operation of the device under large temperature variations. The biological desulfurization method described in this invention, through the combination of a biological desulfurization device and sulfur-oxidizing bacteria in a bioreactor, achieves good desulfurization effect and can maintain stable operation.

[0101] In this invention, solid substances such as sulfur-oxidizing bacteria and sulfur present in the slurry containing elemental sulfur in the bioreactor 5 are introduced into the absorption tower 2 through a circulation section, which can promote the absorption of hydrogen sulfide by the absorption tower 2. According to a preferred embodiment of the present invention, the biological desulfurization method further includes: circulating the slurry containing elemental sulfur to the absorption tower 2 through a circulation pump.

[0102] In this invention, the range of sulfur-containing gases that can be selected is relatively wide. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the sulfur-containing gases include one or more of sulfur-containing natural gas, biogas, blast furnace gas, and petrochemical plant exhaust gas.

[0103] In this invention, the potential sulfur content of the sulfur-containing gas can be selected from a wide range, which is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the potential sulfur content of the sulfur-containing gas is 0.001-5 t / d.

[0104] In this invention, the pressure of the sulfur-containing gas can be selected within a wide range. According to a preferred embodiment of this invention, the pressure of the sulfur-containing gas is 0.1-5 MPa.

[0105] In this invention, the range of selectable biological oxidation temperatures is relatively wide. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the biological oxidation temperature is 10-45°C, preferably 30-37°C.

[0106] In this invention, the range of pH values ​​for biological oxidation is relatively wide, which is illustrative but does not limit the scope of the invention. According to a preferred embodiment of the invention, the pH value for biological oxidation is 6.0-10.0, preferably 7.5-8.5.

[0107] In this invention, the aeration rate of bioreactor 5 can be selected from a relatively wide range, which is illustrative but does not limit the scope of the invention. According to a preferred embodiment of the invention, the aeration rate is 5-50 m³ / h. 3 / h, more preferably 10-30m 3 / h.

[0108] In this invention, the range of selectable ORP values ​​in bioreactor 5 is relatively wide, which is illustrative but does not limit the scope of the invention. According to a preferred embodiment of the invention, the ORP value is -250 to 50 mV.

[0109] In this invention, the range of alkaline solutions that can be selected is relatively wide. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the alkaline solution is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate.

[0110] In this invention, the pH range of the alkaline solution is relatively wide, which is illustrative but does not limit the scope of the invention. According to a preferred embodiment of the invention, the pH of the alkaline solution is 7.0-10.0, and more preferably, the pH of the alkaline solution is 7.5-8.5.

[0111] In this invention, the alkaline solution in bioreactor 5 is circulated to absorption tower 2. The circulation rate of the alkaline solution has a wide range of selectable values. According to a preferred embodiment of this invention, the circulation rate of the alkaline solution is 5-15 m³. 3 / h.

[0112] In this invention, the height of the liquid seal plug can be selected within a wide range. According to a preferred embodiment of this invention, the height of the liquid seal plug is 10-100cm.

[0113] According to a preferred embodiment of the present invention, the flow rate of the sulfur-rich liquid is controlled by an electric regulating valve 18, and the height of the liquid seal sluice is controlled to be 10-100cm.

[0114] According to a preferred embodiment of the present invention, the biological desulfurization method further includes: controlling the flow of sulfur-rich liquid by opening and closing the solenoid valve 19, specifically: when the height of the liquid seal plug is less than 10cm, the solenoid valve 19 is closed; when the height of the liquid seal plug is greater than 10cm, it remains open.

[0115] According to a preferred embodiment of the present invention, the solenoid valve 19 is configured to remain normally closed when power is off, to prevent the electric regulating valve 18 from failing to close during a sudden power outage, which could lead to the failure of the liquid seal sluice and leakage of sulfur-containing gas into the atmospheric pressure bioreactor.

[0116] In this invention, the biological desulfurization method further includes: collecting and detecting operational data such as temperature, pressure, ORP, DO, pH value, sludge concentration, and conductivity in real time through a second automatic control unit, and realizing automated linkage control with aeration unit, dosing device, temperature control unit, centrifuge 15, and other units to achieve control of each parameter.

[0117] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0118] In the following embodiments, biological desulfurization of sulfur-containing gases is carried out in the following ways: Figure 1 The desulfurization process is carried out in the desulfurization unit shown. The biological desulfurization method for sulfur-containing gases includes: the sulfur-containing gas enters the gas scrubbing tower 1, such as... Figure 2 As shown, after washing with clean water, the oil and solid phase impurities are removed. The de-oiled and de-solidified gas enters the absorption tower 2 from the lower part and comes into countercurrent contact with the alkaline solution sprayed from the top of the absorption tower 2, absorbing hydrogen sulfide to obtain a sulfur-rich solution. The treated gas leaves from the top of the absorption tower 2 and enters the gas-liquid separator 3 to further remove the moisture carried in the gas, finally obtaining a dry gas free of hydrogen sulfide, which leaves from the top of the gas-liquid separator 3. The sulfur-rich solution enters the bioreactor 5 through a series of pressure reducing valves 17, electric regulating valves 18, and solenoid valves 19. The sulfur-rich alkaline solution is aerated by an air aerator 6, and the sulfides in the alkaline solution are converted into elemental sulfur under the action of sulfur-oxidizing bacteria, realizing the regeneration of the alkaline solution and obtaining a slurry containing elemental sulfur. The slurry containing elemental sulfur is fed into the absorption tower 2 from the top through the first transfer pump 7.

[0119] When the sludge concentration in the slurry containing elemental sulfur in bioreactor 5 is high, which is not conducive to the circulation of the slurry containing elemental sulfur to the absorption tower 2 and the bioreactor 5 for biological oxidation, the slurry containing elemental sulfur enters the settling tank 8. After gravity settling, elemental sulfur slurry and regenerated alkali solution are obtained. The elemental sulfur slurry is transported to the centrifuge 15 through the second transfer pump 14 for solid-liquid separation to obtain the product bio-sulfur. The separated liquid phase and regenerated alkali solution are returned to the bioreactor 5.

[0120] Example 1

[0121] The sulfur-containing gas is associated natural gas from the oil well, with a volume of 2000 m³. 3 / d, pressure 0.2MPa, hydrogen sulfide content 6000mg / m³ 3 The sulfur-containing gas, after being scrubbed by gas scrubber 1, enters absorber 2. At the top of absorber 2, alkaline solution is sprayed to absorb the hydrogen sulfide in the gas. The alkaline solution in absorber 2 is circulated by bioreactor 5. The pH of the alkaline solution is 8.0, and the circulation rate is 8 m³ / s. 3 / h. The height of the liquid seal plug at the bottom of the absorption tower 2 is controlled at 10-100cm; the sulfur-rich alkaline solution enters the bioreactor 5, and the desulfurizing bacteria in the bioreactor 5 are a compound desulfurizing agent, in which the compound volume ratio of Pseudomonas strain TD-04 and Bacillus cereus strain TD-05 fermentation broth is 1.1:0.9; the temperature of the bioreactor 5 is controlled at 30-35℃, and the air aeration rate is 10-30m³ / h. 3 / h, ORP value -150 to -250mV.

[0122] The hydrogen sulfide content in the purified gas after biological desulfurization is less than 10 mg / m³. 3 .

[0123] Example 2

[0124] The implementation method is the same as in Example 1, except that:

[0125] The sulfur-containing gas is associated natural gas from the oil well, with a volume of 4000 m³. 3 / d, pressure 2MPa, hydrogen sulfide content 4500mg / m³ 3 The sulfur-containing gas, after being scrubbed by gas scrubber 1, enters absorber 2. At the top of absorber 2, alkaline solution is sprayed to absorb hydrogen sulfide from the gas. The alkaline solution in absorber 2 is circulated by bioreactor 5. The pH of the alkaline solution is 8.0, and the circulation rate is 10 m³ / s. 3 / h. The height of the liquid seal plug at the bottom of the absorption tower 2 is controlled at 10-100cm; after being depressurized to 0.2MPa by the pressure reducing device, the sulfur-rich alkaline solution enters the bioreactor 5. The desulfurizing bacteria in the bioreactor 5 are a compound desulfurizing agent, in which the combined volume ratio of Pseudomonas strain TD-04 and Bacillus cereus strain TD-05 fermentation broth is 1.1:0.9; the temperature of the bioreactor 5 is controlled at 30-35℃, and the air aeration rate is 10-30m³ / h. 3 / h, ORP value -100 to -200mV.

[0126] The hydrogen sulfide content in the purified gas after biological desulfurization is less than 10 mg / m³. 3 .

[0127] Example 3

[0128] The implementation method is the same as in Example 1, except that:

[0129] The sulfur-containing gas is associated natural gas from the oil well, with a volume of 5000 m³. 3 / d, pressure 5MPa, hydrogen sulfide content 1500mg / m³ 3 The sulfur-containing gas, after being scrubbed by gas scrubber 1, enters absorber 2. At the top of absorber 2, alkaline solution is sprayed to absorb the hydrogen sulfide in the gas. The alkaline solution in absorber 2 is circulated by bioreactor 5. The pH of the alkaline solution is 8.2, and the circulation rate is 10 m³ / s. 3 / h. The height of the liquid seal plug at the bottom of the absorption tower 2 is controlled at 10-100cm; after being depressurized to 0.2MPa by the pressure reducing device, the sulfur-rich alkaline solution enters the bioreactor 5. The desulfurizing bacteria in the bioreactor 5 are a compound desulfurizing agent, in which the combined volume ratio of Pseudomonas strain TD-04 and Bacillus cereus strain TD-05 fermentation broth is 1.0:1.0; the temperature of the bioreactor 5 is controlled at 30-35℃, and the air aeration rate is 10-30m³ / h. 3 / h, ORP value -180 to -250mV.

[0130] The hydrogen sulfide content in the purified gas after biological desulfurization is less than 10 mg / m³. 3 .

[0131] Example 4

[0132] The implementation method is the same as in Example 1, except that:

[0133] The sulfur-containing gas is associated natural gas from the oil well, with a volume of 6000 m³. 3 / d, pressure 0.2MPa, hydrogen sulfide content 5000mg / m³ 3 The sulfur-containing gas, after being scrubbed by gas scrubber 1, enters absorber 2. At the top of absorber 2, alkaline solution is sprayed to absorb the hydrogen sulfide in the gas. The alkaline solution in absorber 2 is circulated by bioreactor 5. The pH of the alkaline solution is 7.5, and the circulation rate is 15 m³ / s. 3 / h. The height of the liquid seal plug at the bottom of the absorption tower 2 is controlled at 10-100cm; after being depressurized to 0.2MPa by the pressure reducing device, the sulfur-rich alkaline solution enters the bioreactor 5. The desulfurizing bacteria in the bioreactor 5 are a compound desulfurizing agent, in which the compound volume ratio of Pseudomonas strain TD-04, Bacillus cereus strain TD-05, and Bacillus subtilis strain JSHD-4 fermentation broth is 1.2:0.9:0.9; the temperature of the bioreactor 5 is controlled at 30-35℃, and the air aeration rate is 10-30m³ / h. 3 / h, ORP value -150 to -220mV.

[0134] The hydrogen sulfide content in the purified gas after biological desulfurization is less than 10 mg / m³. 3 .

[0135] Example 5

[0136] The implementation method is the same as in Example 1, except that:

[0137] The sulfur-containing gas is associated natural gas from the oil well, with a volume of 2000 m³. 3 / d, pressure 3MPa, hydrogen sulfide content 1500mg / m³ 3 The sulfur-containing gas, after being scrubbed by gas scrubber 1, enters absorber 2. At the top of absorber 2, alkaline solution is sprayed to absorb hydrogen sulfide from the gas. The alkaline solution in absorber 2 is circulated by bioreactor 5. The pH of the alkaline solution is 8.5, and the circulation rate is 8 m³ / s. 3 / h. The height of the liquid seal plug at the bottom of the absorption tower 2 is controlled at 10-100cm; after being depressurized to 0.3MPa by the pressure reducing device, the sulfur-rich alkaline solution enters the bioreactor 5. The desulfurizing bacteria in the bioreactor 5 are a compound desulfurizing agent, in which the compound volume ratio of Pseudomonas strain TD-04, Bacillus cereus strain TD-05, and Bacillus subtilis strain JSHD-4 fermentation broth is 1.2:1.0:0.8; the temperature of the bioreactor 5 is controlled at 30-35℃, and the air aeration rate is 10-30m³ / h. 3 / h, ORP value -50 to -150mV.

[0138] The hydrogen sulfide content in the purified gas after biological desulfurization is less than 10 mg / m³. 3 .

[0139] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A device for biological desulfurization of sulfur-containing gases, characterized in that, The device includes: The absorption unit is used to absorb sulfides in sulfur-containing gases to obtain desulfurized gases and sulfur-rich solutions. A bio-oxidation reaction unit is used to bio-oxidize the sulfur-rich solution; A pressure control unit is located between the absorption unit and the bio-oxidation reaction unit in the connecting pipeline, and is used to reduce the pressure of the sulfur-rich solution and stabilize the pressure.

2. The biological desulfurization device according to claim 1, wherein, The absorption unit includes an absorption tower (2) and a liquid sealing device, the liquid sealing device being used to form a liquid sealing sluice at the bottom of the absorption tower (2); and / or The pressure control unit includes: Pressure reducing valve (17) is used to reduce the pressure of the sulfur-rich liquid; An electrically operated regulating valve (18) located downstream of the pressure reducing valve (17) is used to regulate the flow rate of the sulfur-rich solution and the height of the liquid seal sluice plug; and / or The bio-oxidation reaction unit includes: A bioreactor (5) is used to bio-oxidize the sulfur-rich liquid to obtain a slurry containing elemental sulfur; preferably, the bioreactor (5) is a fluidized bed bioreactor; and / or The elemental sulfur separation system is used to separate elemental sulfur from slurry containing elemental sulfur to obtain elemental sulfur and regenerated alkali solution.

3. The biological desulfurization device according to claim 2, wherein, The absorption unit further includes a gas scrubbing tower (1), located upstream of the absorption tower (2), for removing non-gaseous substances from the sulfur-containing gas; and / or The bioreactor (5) also includes an aeration unit for aerating the bioreactor (5); and / or Nutrient dosing device (12) is used to feed nutrients to bioreactor (5); and / or Alkali dosing device (13) is used to feed fresh alkali solution into bioreactor (5); and / or The elemental sulfur separation system includes: Settling tank (8) settles slurry containing elemental sulfur to obtain elemental sulfur slurry and regenerated alkali solution; and / or Centrifuge (15) is used to separate elemental sulfur slurry into elemental sulfur.

4. The biological desulfurization device according to claim 2 or 3, wherein, The biological desulfurization device also includes: a first automatic control unit for monitoring and controlling the liquid seal sluice gate; Preferably, the first automatic control unit includes: A level gauge installed at the bottom of the absorber is used to monitor the height of the liquid seal sluice gate; and / or A solenoid valve (19) is connected in series downstream of the electric regulating valve (18) to control the flow of the sulfur-rich liquid by opening and closing.

5. The biological desulfurization device according to any one of claims 2-4, wherein, The biological desulfurization device also includes: a second automatic control unit for monitoring and controlling the biological oxidation reaction unit; Preferably, the second automatic control unit includes: Thermometers, flow meters, level gauges, pH meters, ORP meters, sludge concentration meters, dissolved oxygen meters, and conductivity meters are installed in the bioreactor (5); and / or Temperature control unit is used to control the reaction temperature inside the bioreactor (5).

6. The biological desulfurization device according to any one of claims 2-5, wherein, The biological desulfurization unit also includes: A first transfer pump (7) is used to circulate the slurry containing elemental sulfur in the bioreactor (5) to the absorption tower (2); and / or Gas-liquid separator (3) is used to separate desulfurization gas into gas and liquid.

7. A method for biological desulfurization of sulfur-containing gases, characterized in that, This method employs the biological desulfurization device according to any one of claims 1-6, and the method includes: After the sulfur-containing gas comes into contact with the alkaline solution in the absorption unit, desulfurized gas and sulfur-rich solution are obtained; the sulfur-rich solution is depressurized to 0.1-0.3 MPa and then enters the bio-oxidation reaction unit for bio-oxidation.

8. The biological desulfurization method according to claim 7, wherein, The method includes: The sulfur-containing gas comes into contact with the washing medium in the gas scrubbing tower (1) to remove the non-gaseous substances in the sulfur-containing gas. The gas then enters the absorption tower (2) and comes into contact with the alkaline solution to obtain desulfurized gas and sulfur-rich solution. The sulfur-rich solution is depressurized to 0.1-0.3 MPa and then enters the bioreactor (5) for bio-oxidation; Preferably, the method further includes: The desulfurized gas is dehydrated by a gas-liquid separator (3) to obtain dehydrated gas; and / or The bioreactor (5) is aerated via an aeration unit; and / or The slurry containing elemental sulfur obtained by bio-oxidation is separated to obtain elemental sulfur and regenerated alkali solution.

9. The biological desulfurization method according to claim 7 or 8, wherein, Biological oxidation uses a compound desulfurizing agent, preferably one or more of alkali-resistant sulfur-oxidizing bacteria; Preferably, the alkali-tolerant sulfur-oxidizing bacteria are selected from one or more of Pseudomonas, Aureobacterium, Bacillus subtilis, sulfur-oxidizing bacteria, thioalkali-resistant Vibrio, and denitrifying thiobacillus; More preferably, it is one or more of Pseudomonas, Aureobacterium, and Bacillus subtilis; and / or The biological desulfurization method further includes: circulating the slurry containing elemental sulfur to the absorption tower (2) via a circulating pump.

10. The biological desulfurization method according to any one of claims 7-9, wherein, Sulfur-containing gases include one or more of the following: sulfur-containing natural gas, biogas, blast furnace gas, and petrochemical plant exhaust gas; preferably, the latent sulfur content of the sulfur-containing gas is 0.001-5 t / d; and / or The pressure of the sulfur-containing gas is 0.1-5 MPa; and / or The volume of sulfur-containing gas is not less than 1000 m³. 3 / d, preferably 1000-8000m 3 / d; and / or The biological oxidation temperature is 10-45℃, preferably 30-37℃; and / or The pH value of the alkaline solution is 7-10, preferably 7.5-8.

5.

11. The biological desulfurization method according to any one of claims 7-10, wherein, In the absorption tower (2), the height of the liquid seal plug is 10-100cm; Preferably, the flow rate of the sulfur-rich liquid is controlled by an electric regulating valve (18), thereby controlling the height of the liquid seal sluice plug; Preferably, the biological desulfurization method further includes: The flow of the sulfur-rich liquid is controlled by the opening and closing of the solenoid valve (19). When the height of the liquid seal plug is less than 10cm, the solenoid valve (19) is closed; when the height of the liquid seal plug is greater than 10cm, it remains open; when the system experiences a sudden power outage, the solenoid valve (19) is closed.

12. The biological desulfurization method according to any one of claims 7-11, wherein, The biological desulfurization method also includes: collecting operational data in real time and automatically controlling various parameters through a second automatic control unit.

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