Device and method for removing hydrogen sulfide in sulfur-containing gas

Abstract

The invention relates to the technical field of environment-friendly purification, and discloses a device and method for removing hydrogen sulfide in sulfur-containing gas, and the device comprises a packing absorption tower, a biological aerobic reactor and a barren liquor pump; a sprayer is arranged at the top of the packing absorption tower and is used for spraying alkali liquor to convert hydrogen sulfide in the sulfur-containing gas into sulfide; a sulfur oxidizing flora is arranged in the biological aerobic reactor and is used for oxidizing sulfide into elemental sulfur and obtaining a barren solution containing sulfate; and the filler absorption tower is also filled with an immobilized sulfur reducing flora filler which is used for reducing sulfate in the sulfate-containing barren liquor returned by the barren liquor pump into sulfide. According to the device and the method, the problem of sulfate accumulation is solved, the sulfur-containing gas is completely converted into elemental sulfur, no sulfate waste liquid is discharged, meanwhile, the yield of the elemental sulfur is increased, the system stability is kept, the desulfurization effect is enhanced, the H2S content in the treated purified gas is lower than 10 mg / m < 3 >, and the generation rate of the elemental sulfur is larger than 98%.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection purification, and in particular to a device and method for removing hydrogen sulfide from sulfur-containing gas. Background Art

[0002] Hydrogen sulfide is highly toxic, corrosive and has a foul odor. It is an atmospheric pollutant that must be eliminated or controlled. It is the main sulfur-containing component in gases such as natural gas, coke oven gas, refinery gas, semi-water gas and biogas. Its presence not only causes corrosion of equipment and pipelines and catalyst poisoning, but also seriously threatens personal safety. Therefore, finding an economical and effective hydrogen sulfide removal technology, especially a resource-based process that can simultaneously achieve sulfur recovery, has been a goal that researchers have been pursuing for nearly a hundred years, and various methods have emerged one after another.

[0003] Typical processes include the Claus process, iron oxide process, liquid absorption process and wet oxidation process. These traditional physical and chemical methods generally require high temperature and high pressure, or consume a large amount of chemicals and catalysts, with high investment and operating costs. The technology of removing hydrogen sulfide by microbial methods has become a research hotspot in recent years. Its basic principle is to dissolve H2S in water and remove it from acidic gases by the oxidation of H2S by microorganisms. Compared with traditional physical and chemical methods, microbial methods have mild reaction conditions, greatly reduced consumption of chemicals and energy, low operating costs, and no secondary pollution, so they have great development prospects.

[0004] At present, the principle of gas biological desulfurization and sulfur recovery is that alkali solution chemically absorbs hydrogen sulfide in the gas phase. Under the aerobic environment and the biocatalytic action of Thiobacillus, the sulfide is biologically oxidized to elemental sulfur and alkali solution is regenerated. Under the condition of optimal redox potential, the elemental sulfur yield of the currently used sulfur oxidizing bacteria is generally 80-85%. There is still more than 10% of the elemental sulfur converted into sulfate and enters the desulfurization system. Long-term operation will cause system acidification and seriously affect the desulfurization efficiency. In order to prevent the accumulation of sulfate, it is necessary to lead a small continuous stream of flow out of the bioreactor and add alkali solution (such as sodium hydroxide, sodium carbonate or sodium bicarbonate) for supplementation. The regular discharge of sulfate waste liquid brings about the loss of elemental sulfur resources, which is one of the important problems currently faced by the biological desulfurization process.

[0005] The existing technology for treating sulfate wastewater produced by biological desulfurization process is: evaporation in a three-effect evaporator and treatment in a crystallization system to produce sodium sulfate for sale, basically achieving no discharge of wastewater. However, the evaporation and crystallization process brings problems such as high equipment investment and operating energy consumption costs, which does not meet the requirements of the current energy-saving and environmental protection industry.

[0006] Therefore, recovering sulfur resources from sulfate waste liquid in order to maximize the recovery of elemental sulfur, realize closed-loop biological desulfurization, meet emission standards for waste gas, and achieve near-zero emission of waste liquid has become an important issue that needs to be solved urgently in line with the current national environmental protection industry development concept and adapt to the purpose of national ecological civilization construction. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems in the prior art of sulfate accumulation during biological desulfurization treatment of sulfur-containing gas, severe loss of elemental sulfur caused by discharge of sulfate waste liquid, low desulfurization efficiency and low yield of elemental sulfur, and to provide a device and method for removing hydrogen sulfide from sulfur-containing gas.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides a device for removing hydrogen sulfide from sulfur-containing gas, wherein the device comprises a packed absorption tower, a biological aerobic reactor and a lean liquid pump;

[0009] Wherein, a sprayer is provided at the top of the packed absorption tower for spraying alkali solution to convert hydrogen sulfide in the sulfur-containing gas into sulfide;

[0010] The biological aerobic reactor is provided with a sulfur-oxidizing bacteria group for oxidizing sulfide into elemental sulfur and obtaining a lean solution containing sulfate;

[0011] The packed absorption tower is also filled with fixed sulfur-reducing bacteria fillers for reducing sulfate in the sulfate-containing barren liquid returned by the barren liquid pump into sulfide.

[0012] The second aspect of the present invention provides a method for removing hydrogen sulfide from sulfur-containing gas, which comprises subjecting the sulfur-containing gas to chemical absorption, biological oxidation treatment and anaerobic reduction treatment in the device described in the first aspect to obtain elemental sulfur.

[0013] Preferably, the sulfur-containing gas is selected from at least one of natural gas, oilfield associated gas, synthesis gas and biogas;

[0014] Preferably, the concentration of hydrogen sulfide in the sulfur-containing gas is 0.1 vol%-5 vol% by volume.

[0015] Through the above technical solution, the present invention achieves the following beneficial technical effects:

[0016] (1) The present invention adopts the chemical absorption-biological oxidation-anaerobic reduction coupling technology, adds a fixed sulfur-reducing bacterial community carrier as a filler in the absorption tower, improves the gas-liquid mass transfer and sulfate reduction effect, and strictly controls the dissolved oxygen and redox potential in the biological aerobic reactor to completely convert the sulfur-containing gas into elemental sulfur, thereby solving the problem of sulfate accumulation. It does not increase the complexity of the equipment and system, but can also improve the elemental sulfur yield, maintain the system stability, and enhance the desulfurization effect. The H2S content in the post-purification gas is less than 10 mg / m 3 , the generation rate of elemental sulfur is greater than 98%.

[0017] (2) The present invention replaces the traditional filler in the absorption tower with immobilized sulfur-reducing bacteria. When the desulfurized liquid containing sulfate is circulated to the absorption tower, the sulfate is reduced to sulfide under the action of sulfur-reducing bacteria, thereby solving the problem of sulfate accumulation and waste liquid discharge.

[0018] (3) The present invention integrates the sulfur oxidation and sulfur reduction processes into the same system, achieving the purpose of closed-loop biological desulfurization and near-zero discharge of waste liquid, maximizing the recovery of sulfur resources, and ultimately achieving the unity of environmental and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a device for removing hydrogen sulfide from sulfur-containing gas.

[0020] Description of Reference Numerals

[0021] 1. Sulfur-containing gas 2. Purified gas after desulfurization 3. Air

[0022] 11. Packing absorption tower 12. Rich liquid pump 13. Biological aerobic reactor

[0023] 14. Sedimentation tank 15. Centrifuge 16. Lean liquid pump

[0024] 17. Immobilized reducing bacteria filler DETAILED DESCRIPTION

[0025] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0026] In order to achieve the above-mentioned object, the first aspect of the present invention provides a device for removing hydrogen sulfide from sulfur-containing gas, wherein the device comprises a packed absorption tower, a biological aerobic reactor and a lean liquid pump;

[0027] Wherein, a sprayer is provided at the top of the packed absorption tower for spraying alkali solution to convert hydrogen sulfide in the sulfur-containing gas into sulfide;

[0028] The biological aerobic reactor is provided with a sulfur-oxidizing bacteria group for oxidizing sulfide into elemental sulfur and obtaining a lean solution containing sulfate;

[0029] The packed absorption tower is also filled with fixed sulfur-reducing bacteria fillers for reducing sulfate in the sulfate-containing barren liquid returned by the barren liquid pump into sulfide.

[0030] In the present invention, the immobilized sulfur-reducing bacteria filler contains polyvinyl alcohol, sodium alginate, activated carbon and sulfur-reducing bacteria liquid, wherein, based on the total mass of the immobilized sulfur-reducing bacteria filler, the content of polyvinyl alcohol in the immobilized sulfur-reducing bacteria filler is 5wt%-10wt%, the content of sodium alginate is 1wt%-3wt%, the content of activated carbon is 0.3wt%-0.8wt%, and the content of sulfur-reducing bacteria liquid is 20wt%-50wt%.

[0031] In the present invention, the sulfur-reducing bacteria liquid is selected from at least one of Pseudomonas, Desulfovibrio and Desulfovibrio campylobacter. The above bacteria can be commercially available.

[0032] In the present invention, the sulfur oxidizing bacteria group is selected from at least one of Thiobacillus thiosulfuri, Thiobacillus denitrificans and Thiobacillus naples. The above bacteria can be commercially available.

[0033] In the present invention, the packed absorption tower is provided with an air outlet at the top, an air inlet and a liquid discharge port at the bottom, and the gas containing hydrogen sulfide enters from the air inlet at the lower end of the tower body and forms reverse contact with the alkali liquid flowing down in the middle of the tower body, the hydrogen sulfide in the gas is absorbed, and the purified gas is discharged from the air outlet at the upper end of the tower body.

[0034] In the present invention, there is no particular limitation on the position where the sulfur-containing gas enters the packed absorption tower. For example, the air inlet can be set at the upper end of the packed absorption tower or at the lower end of the packed absorption tower. Preferably, the sulfur-containing gas enters from the lower end of the packed absorption tower.

[0035] In the present invention, when the sulfur-containing gas enters from the lower air inlet of the packed absorption tower, the sulfur-containing gas is in reverse contact with the alkali solution sprayed on the top of the packed absorption tower more fully, and the reaction and absorption are more thorough.

[0036] According to some embodiments of the present invention, the bioaerobic reactor is an airlift internal circulation bioreactor, and an aeration distributor is provided inside the bioaerobic reactor so that the dissolved oxygen content in the bioaerobic reactor is 0.3-1.0 mg / L.

[0037] In the present invention, a dissolved oxygen meter is further provided inside the bioaerobic reactor for monitoring the dissolved oxygen content in the bioaerobic reactor. The technician adjusts the external fan of the bioaerobic reactor to control the aeration volume according to the actual dissolved oxygen content, so that the dissolved oxygen content is within a normal range, thereby ensuring the normal growth of the sulfur-oxidizing bacteria in the bioaerobic reactor, effectively inhibiting the production of sulfate, and improving the conversion efficiency of sulfide.

[0038] According to some embodiments of the present invention, a fan and a gas flow meter are further provided outside the bioaerobic reactor so that O2 and S in the bioaerobic reactor are 2- The amount of substance ratio is 0.7-1, and the redox potential is -400mV to -250mV.

[0039] In the present invention, the air volume (oxygen) is controlled by the fan, and the hydrogen sulfide content is controlled by the raw gas flow meter, thereby controlling the ratio of the amount of oxygen and sulfide substances. The redox potential is reflected by various reducing and oxidizing substances in the solution, such as S 2- It has strong reducing properties, while O2 has oxidizing properties. By controlling the amount of air, the redox potential value can be adjusted.

[0040] In the present invention, a thermometer, a pH meter and a conductivity meter are also installed in the bioaerobic reactor, so that the temperature in the bioaerobic reactor is 25-40° C., the pH value is 8-11, and the conductivity value is 35-60 mS / cm.

[0041] In the present invention, by installing online detection instruments in the bioaerobic reactor, the key parameters such as temperature, pH value, ORP value, DO value and conductivity value in the bioaerobic reactor are automatically controlled, so that the dissolved oxygen content, nO2 / nS 2- The value and redox potential are within the above-defined ranges, the sulfur-oxidizing bacteria community is kept at a high concentration and high activity, sulfide is more efficiently converted into elemental sulfur, the formation rate of elemental sulfur is increased, and the formation of sulfate by-products is minimized, thereby achieving efficient and smooth operation of the biological desulfurization process.

[0042] According to some embodiments of the present invention, the device further comprises a rich liquid pump, a sedimentation tank, and a centrifuge.

[0043] Preferably, the rich liquid pump is connected to the discharge port of the packed absorption tower and the water inlet of the biological aerobic reactor respectively; the inlet of the sedimentation tank is connected to the overflow port of the biological aerobic reactor, and the discharge port of the sedimentation tank is connected to the centrifuge.

[0044] In the present invention, the rich liquid for absorbing hydrogen sulfide is pressed into the water inlet of the biological aerobic reactor through a rich liquid pump, and flows out from the overflow port to the sedimentation tank.

[0045] In the present invention, a drain port is provided below the settling tank, and the sulfur solution after settling treatment in the settling tank is sent to a centrifuge through the drain port to separate sulfur, and the regenerated alkali solution is returned to the packed absorption tower through a lean liquid pump for recycling.

[0046] In the present invention, if Figure 1 As shown, the sulfur-containing gas 1 enters the packed absorption tower 11 (wherein the fixed sulfur-reducing bacteria packing 17 is also provided) from bottom to top, and after reverse contact reaction and absorption with the alkali solution sprayed on the top of the tower (the regeneration alkali solution circulated back by the lean liquid pump 16, which contains sulfate), the alkali solution converts the hydrogen sulfide in the sulfur-containing gas 1 into sulfide, which flows out from the packing from top to bottom to obtain a rich liquid absorbing sulfide, and the desulfurized purified gas 2 is discharged from the gas outlet at the upper end of the packed absorption tower 11. The rich liquid absorbing sulfide is pressed from the bottom of the packed absorption tower 11 through the rich liquid pump 12 from the water inlet of the biological aerobic reactor 13, and the air 3 enters the biological aerobic reactor 13 from the ventilation pipe at the bottom of the biological aerobic reactor 13. Under the air aeration and the biological catalysis of the sulfur-oxidizing bacteria, the soluble sulfide in the rich liquid absorbing sulfide is converted into elemental sulfur and byproduct sulfate to obtain a regeneration liquid containing sulfur and sulfate. The regenerated liquid enters the sedimentation tank 14 through the overflow port of the biological aerobic reactor 13 for sedimentation to obtain a supernatant and a precipitated sulfur solution, wherein the precipitated sulfur solution is sent to the centrifuge 15 through the discharge port of the sedimentation tank 14, and solid-liquid separation is achieved in the centrifuge 15 to obtain biological sulfur; the supernatant (containing sulfate and alkali solution) is returned to the packed absorption tower 11 for recycling through the lean liquid pump 16, and the sulfate therein is reduced to sulfide by the fixed sulfur-reducing bacteria filler 17 filled in the packed absorption tower 11, and then merged into the rich liquid that absorbs sulfide to recover elemental sulfur, thereby solving the problem of sulfate accumulation and waste liquid discharge.

[0047] The second aspect of the present invention provides a method for removing hydrogen sulfide from sulfur-containing gas, the method comprising subjecting the sulfur-containing gas to chemical absorption, biological oxidation treatment and anaerobic reduction treatment in the device described in the first aspect to obtain elemental sulfur.

[0048] According to some embodiments of the present invention, the method comprises the following steps:

[0049] (1) chemically absorbing the sulfur-containing gas in a packed absorption tower included in the device to obtain a sulfide absorption rich liquid A;

[0050] (2) subjecting the sulfide absorption rich liquid A to biological oxidation treatment in a biological aerobic reactor included in the device to obtain elemental sulfur and a sulfate-containing lean liquid;

[0051] (3) subjecting the sulfate-containing lean liquid to anaerobic reduction treatment in a packed absorption tower included in the device to obtain a sulfide absorption rich liquid B;

[0052] (4) The sulfide absorption rich liquid B is treated in step (2) to obtain elemental sulfur.

[0053] According to some embodiments of the present invention, the chemical absorption method comprises: using alkaline solution to convert hydrogen sulfide in the sulfur-containing gas into sulfide to obtain sulfide absorption rich liquid A.

[0054] Preferably, the alkali solution is an alkaline solution containing sodium; preferably, the alkali solution is selected from at least one of NaCO3, NaOH, and NaHCO3; more preferably, the concentration of the alkali solution is 5-30 g / L and the pH value is 8-11.

[0055] According to some embodiments of the present invention, the anaerobic reduction treatment method includes: using an immobilized sulfur-reducing bacteria filler to reduce sulfate in the sulfate-lean solution into sulfide to obtain the sulfide-absorbing rich solution B.

[0056] In the present invention, there is no particular restriction on the source of the immobilized sulfur-reducing bacteria filler, which can be purchased from the market or prepared by itself. The immobilized reducing bacteria filler is prepared by a cross-linking embedding method, for example, the specific preparation method is: weigh a certain amount of polyvinyl alcohol, sodium alginate, and activated carbon in a container, add a certain amount of sterile water, heat and dissolve to a paste, cool to about 40°C, quickly add a certain amount of sulfur-reducing bacteria liquid, mix and stir, and use a syringe to draw the mixed liquid and drop it into a 2% calcium chloride saturated boric acid solution for cross-linking molding.

[0057] Preferably, based on the total mass of the immobilized sulfur-reducing bacteria filler, the content of polyvinyl alcohol in the immobilized sulfur-reducing bacteria filler is 5wt%-10wt%, the content of sodium alginate is 1wt%-3wt%, the content of activated carbon is 0.3wt%-0.8wt%, and the content of sulfur-reducing bacteria liquid is 20wt%-50wt%.

[0058] In the present invention, when the content of each substance in the immobilized sulfur-reducing bacteria filler meets the above range, the immobilized pellets have excellent performance and the sulfate degradation rate is above 85%; when the content of each substance in the immobilized sulfur-reducing bacteria filler does not meet the above range, the mechanical and mass transfer performance of the immobilized pellets will be poor and the desulfurization rate will be low.

[0059] Preferably, the sulfur-reducing bacteria liquid is selected from at least one of Pseudomonas, Desulfovibrio and Desulfovibrio.

[0060] According to some embodiments of the present invention, the biological oxidation treatment method includes using a sulfur-oxidizing bacteria group to oxidize the sulfide in the sulfide-absorbing rich liquid A and / or B into elemental sulfur.

[0061] Preferably, the sulfur oxidizing bacteria are selected from at least one of Thiobacillus thiosulfurans, Thiobacillus denitrificans and Thiobacillus naples.

[0062] According to some embodiments of the present invention, the sulfur-containing gas is selected from at least one of natural gas, oilfield associated gas, synthesis gas and biogas.

[0063] Preferably, the concentration of hydrogen sulfide in the sulfur-containing gas is 0.1 vol%-5 vol% by volume.

[0064] According to a particularly preferred embodiment of the present invention, the present invention provides a method for removing hydrogen sulfide from sulfur-containing gas, and the specific operation method includes:

[0065] The concentration of alkali solution in the packed absorption tower 11 is 15-25g / L, and the immobilized reducing bacteria filler 17 includes 5wt%-10wt% of polyvinyl alcohol, 1wt%-3wt% of sodium alginate, 0.3wt%-0.8wt% of activated carbon, and 20wt%-50wt% of sulfur-reducing bacteria liquid (the sulfur-reducing bacteria liquid is selected from the composite bacteria of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are selected from at least one of Thiobacillus excreta, Thiobacillus denitrificans and Thiobacillus Naples, and the dissolved oxygen content is 0.3mg / L-1mg / L, nO2 / nS 2- The value is 0.7-1.0, and the redox potential is -400mV to -350mV.

[0066] The present invention will be described in detail below through examples.

[0067] The hydrogen sulfide content was determined by iodine titration.

[0068] The elemental sulfur production rate is the percentage of the mass of elemental sulfur in the lean solution to all sulfur elements in the rich solution.

[0069] Example 1

[0070] according to Figure 1 The device shown is used to remove hydrogen sulfide from sulfur-containing gas.

[0071] The content of hydrogen sulfide in the sulfur-containing gas is 0.1% (volume fraction), the concentration of alkali solution in the packed absorption tower 11 is 15g / L, the immobilized reducing bacteria filler 17 includes 7wt% of polyvinyl alcohol, 2.5wt% of sodium alginate, 0.4wt% of activated carbon, and 20wt% of sulfur-reducing bacteria liquid (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are a composite flora of sulfur-excreting Thiobacillus and denitrifying Thiobacillus, the dissolved oxygen content is 0.3mg / L, nO2 / nS 2- The value is 0.75, and the ORP redox potential is -350 mV. The hydrogen sulfide content in the purified gas 2 is measured to be 0, and the elemental sulfur generation rate is 99.5%.

[0072] Example 2

[0073] according to Figure 1 The device shown is used to remove hydrogen sulfide from sulfur-containing gas.

[0074] The content of hydrogen sulfide in the sulfur-containing gas is 0.1% (volume fraction), the concentration of alkali solution in the packed absorption tower 11 is 20g / L, the immobilized reducing bacteria filler 17 includes 8.5wt% of polyvinyl alcohol, 2wt% of sodium alginate, 0.6wt% of activated carbon, and 40wt% of sulfur-reducing bacteria liquid (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are a composite flora of denitrifying Thiobacillus and Naples Thiobacillus, the dissolved oxygen content is 0.5mg / L, nO2 / nS 2- The value is 0.88, and the ORP redox potential is -300mV. The hydrogen sulfide content in the purified gas 2 is 0mg / m 3 , the elemental sulfur generation rate is 98.1%.

[0075] Example 3

[0076] according to Figure 1 The device shown is used to remove hydrogen sulfide from sulfur-containing gas.

[0077] The hydrogen sulfide content in the sulfur-containing gas is 0.5% (volume fraction), the alkali solution concentration in the packed absorption tower 11 is 15g / L, the immobilized reducing bacteria filler 17 includes 7wt% of polyvinyl alcohol, 2.5wt% of sodium alginate, 0.4wt% of activated carbon, and 20wt% of sulfur-reducing bacteria liquid (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are selected from the composite flora of Thiobacillus excreta and Thiobacillus napolini, the dissolved oxygen content is 0.3mg / L, nO2 / nS 2- The value is 0.71, and the ORP redox potential is -350mV. The hydrogen sulfide content in the purified gas 2 is 1mg / m 3 , the elemental sulfur generation rate is 98.5%.

[0078] Example 4

[0079] according to Figure 1 The device shown is used to remove hydrogen sulfide from sulfur-containing gas.

[0080] The hydrogen sulfide content in the sulfur-containing gas is 0.5% (volume fraction), the alkali solution concentration in the packed absorption tower 11 is 20g / L, the immobilized reducing bacteria filler 17 includes 8.5wt% of polyvinyl alcohol, 2wt% of sodium alginate, 0.6wt% of activated carbon, and 40wt% of sulfur-reducing bacteria liquid (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are a composite flora of sulfur-excreting Thiobacillus and denitrifying Thiobacillus, the dissolved oxygen content is 0.5mg / L, nO2 / nS 2- The value is 0.85, and the ORP redox potential is -300mV. The hydrogen sulfide content in the purified gas 2 is 0mg / m 3 , the elemental sulfur generation rate is 99.6%.

[0081] Example 5

[0082] according to Figure 1 The device shown is used to remove hydrogen sulfide from sulfur-containing gas.

[0083] The hydrogen sulfide content in the sulfur-containing gas is 1% (volume fraction), the alkali solution concentration in the packed absorption tower 11 is 20g / L, the immobilized reducing bacteria filler 17 includes 7wt% of polyvinyl alcohol, 2.5wt% of sodium alginate, 0.4wt% of activated carbon, and 20wt% of sulfur-reducing bacteria liquid (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are a composite flora of Thiobacillus excreta and Thiobacillus denitrificans, the dissolved oxygen content is 0.6mg / L, nO2 / nS 2- The value is 0.83, and the ORP redox potential is -350mV. The hydrogen sulfide content in the purified gas 2 is 3mg / m 3 , the elemental sulfur generation rate is 99.8%.

[0084] Example 6

[0085] according to Figure 1 The device shown is used to remove hydrogen sulfide from sulfur-containing gas.

[0086] The hydrogen sulfide content in the sulfur-containing gas is 1% (volume fraction), the alkali solution concentration in the packed absorption tower 11 is 25g / L, the fixed reducing bacteria filler 17 includes 8.5wt% of polyvinyl alcohol, 2wt% of sodium alginate, 0.6wt% of activated carbon, and 40wt% of sulfur-reducing bacteria liquid (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are selected from the composite flora of Thiobacillus excreta and Thiobacillus napolini, the dissolved oxygen content is 0.8mg / L, nO2 / nS 2-The value is 0.96, and the ORP redox potential is -300mV. The hydrogen sulfide content in the purified gas 2 is measured to be 1mg / m 3 , the elemental sulfur generation rate is 98.3%.

[0087] Example 7

[0088] according to Figure 1 The device shown is used to remove hydrogen sulfide from sulfur-containing gas.

[0089] The hydrogen sulfide content in the sulfur-containing gas is 5% (volume fraction), the alkali solution concentration in the packed absorption tower 11 is 20g / L, the immobilized reducing bacteria filler 17 includes 7wt% of polyvinyl alcohol, 2.5wt% of sodium alginate, 0.4wt% of activated carbon, and 20wt% of sulfur-reducing bacteria liquid (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are a composite flora of denitrifying Thiobacillus and Naples Thiobacillus, the dissolved oxygen content is 0.6mg / L, nO2 / nS 2- The value is 0.74, and the ORP redox potential is -350mV. The hydrogen sulfide content in the purified gas 2 is 8mg / m 3 , the elemental sulfur generation rate is 98.8%.

[0090] Example 8

[0091] according to Figure 1 The device shown is used to remove hydrogen sulfide from sulfur-containing gas.

[0092] The hydrogen sulfide content in the sulfur-containing gas is 5% (volume fraction), the alkali solution concentration in the packed absorption tower 11 is 25g / L, the immobilized reducing bacteria filler 17 includes 8.5wt% of polyvinyl alcohol, 2wt% of sodium alginate, 0.6wt% of activated carbon, and 40wt% of sulfur-reducing bacteria liquid (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria are a composite flora of sulfur-excreting Thiobacillus and denitrifying Thiobacillus, the dissolved oxygen content is 0.8mg / L, nO2 / nS 2- The value is 0.87, and the ORP redox potential is -300mV. The hydrogen sulfide content in the purified gas 2 is 5mg / m 3 , the elemental sulfur generation rate is 99.1%.

[0093] Comparative Example 1

[0094] The same method as in Example 5 was used, except that the packed absorption tower 11 was filled with ball ring packing. The hydrogen sulfide content in the purified gas 2 was measured to be 18 mg / m 3 , the elemental sulfur generation rate is 88.3%.

[0095] Comparative Example 2

[0096] The same method as in Example 5 is used, except that the dissolved oxygen content in the bioaerobic reactor 13 is 1.8 mg / L, nO2 / nS 2- The value is 2.5, and the ORP redox potential is -150mV. The hydrogen sulfide content in the purified gas 2 is 13mg / m 3 , the elemental sulfur generation rate is 93.2%.

[0097] Comparative Example 3

[0098] The same method as in Example 5 is used, except that the packing absorption tower 11 is filled with ball ring packing, and the dissolved oxygen content in the biological aerobic reactor 13 is 1.8 mg / L, nO2 / nS 2- The value is 2.5, and the ORP redox potential is -150mV. The hydrogen sulfide content in the purified gas 2 is measured to be 21mg / m 3 , the elemental sulfur generation rate is 82.7%.

[0099] Comparative Example 4

[0100] The same method as in Example 5 was used, except that the sulfur oxidizing bacteria in the biological aerobic reactor 13 were replaced with Thiobacillus thiooxidans and Sulfolobus brunneri. The hydrogen sulfide content in the purified gas 2 was measured to be 15 mg / m 3 , the elemental sulfur generation rate is 87.5%.

[0101] Comparative Example 5

[0102] The same method as in Example 5 is used, except that the immobilized reducing bacteria filler 17 in the packed absorption tower 11 includes 15wt% polyvinyl alcohol, 5wt% sodium alginate, 2wt% activated carbon, and 15wt% sulfur-reducing bacteria solution. The hydrogen sulfide content in the purified gas 2 is measured to be 10mg / m 3 , the elemental sulfur generation rate is 91.2%.

[0103] It can be seen from the data of Examples 1-8 that the method for removing hydrogen sulfide provided by the present invention, by adding the immobilized sulfur-reducing bacteria filler 17 in the packed absorption tower 11 and strictly controlling the dissolved oxygen and the redox potential in the biological aerobic reactor 13, can improve the gas-liquid mass transfer and sulfate reduction effect, reduce the generation of sulfate, and increase the elemental sulfur generation rate, so that the H2S content in the treated purified gas is less than 10 mg / m 3, the generation rate of elemental sulfur is greater than 98%. Comparative Example 1 changes the packing in the packing absorption tower 11, resulting in an increase in the content of hydrogen sulfide in the purified gas and a decrease in the generation rate of elemental sulfur; Comparative Example 2 changes the conditions in the biological aerobic reactor 13, resulting in an increase in the content of hydrogen sulfide in the purified gas and a decrease in the generation rate of elemental sulfur; Comparative Example 3 simultaneously changes the packing in the packing absorption tower 11 and the conditions in the biological aerobic reactor 13, resulting in a further increase in the content of hydrogen sulfide in the purified gas and a significant decrease in the generation rate of elemental sulfur; Comparative Example 4 changes the type of sulfur-oxidizing bacteria in the biological aerobic reactor 13, resulting in an increase in the content of hydrogen sulfide in the purified gas and a decrease in the generation rate of elemental sulfur; Comparative Example 5 changes the substance content of the fixed sulfur-reducing bacteria in the packing absorption tower 11, resulting in an increase in the content of hydrogen sulfide in the purified gas and a decrease in the generation rate of elemental sulfur.

[0104] In summary, the present invention uses chemical absorption-biological oxidation-anaerobic reduction coupling technology to integrate the sulfur oxidation and sulfur reduction processes into the same system, completely converting the sulfur-containing gas into elemental sulfur, solving the problem of sulfate accumulation, and not increasing the complexity of the equipment and system, while improving the elemental sulfur yield and realizing a closed-loop biological desulfurization cycle without waste liquid discharge.

[0105] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A device for removing hydrogen sulfide from sulfur-containing gas, characterized in that: The device comprises a packed absorption tower, a biological aerobic reactor and a lean liquid pump; Wherein, a sprayer is provided at the top of the packed absorption tower for spraying alkali solution to convert hydrogen sulfide in the sulfur-containing gas into sulfide; The biological aerobic reactor is provided with a sulfur-oxidizing bacteria group for oxidizing sulfide into elemental sulfur and obtaining a lean solution containing sulfate; The packed absorption tower is also filled with fixed sulfur-reducing bacteria fillers for reducing sulfate in the sulfate-containing barren liquid returned by the barren liquid pump into sulfide.

2. The device according to claim 1, wherein: The biological aerobic reactor is an airlift internal circulation biological reactor, and an aeration distributor is arranged at the bottom, so that the dissolved oxygen content in the biological aerobic reactor is 0.3-1 mg / L.

3. The device according to any one of claims 1 or 2, wherein: The bioaerobic reactor is also provided with a fan and a gas flow meter outside so that the O2 and S in the bioaerobic reactor 2- The amount of substance ratio is 0.7-1, and the redox potential is -400mV to -250mV.

4. The device according to any one of claims 1 to 3, wherein: The device also includes a rich liquid pump, a sedimentation tank and a centrifuge; Preferably, the rich liquid pump is connected to the discharge port of the packed absorption tower and the water inlet of the biological aerobic reactor respectively; the inlet of the sedimentation tank is connected to the overflow port of the biological aerobic reactor, and the discharge port of the sedimentation tank is connected to the centrifuge.

5. A method for removing hydrogen sulfide from sulfur-containing gas, characterized in that: The method comprises subjecting the sulfur-containing gas to chemical absorption, biological oxidation treatment and anaerobic reduction treatment in the device described in any one of claims 1 to 4 to obtain elemental sulfur.

6. The method according to claim 5, wherein: The method comprises the following steps: (1) chemically absorbing the sulfur-containing gas in a packed absorption tower included in the device to obtain a sulfide absorption rich liquid A; (2) subjecting the sulfide absorption rich liquid A to biological oxidation treatment in a biological aerobic reactor included in the device to obtain elemental sulfur and a sulfate-containing lean liquid; (3) subjecting the sulfate-containing lean liquid to anaerobic reduction treatment in a packed absorption tower included in the device to obtain a sulfide absorption rich liquid B; (4) The sulfide absorption rich liquid B is treated in step (2) to obtain elemental sulfur.

7. The method according to claim 6, wherein: The chemical absorption method comprises: using alkaline solution to convert hydrogen sulfide in the sulfur-containing gas into sulfide to obtain sulfide absorption rich liquid A; Preferably, the alkali solution is an alkaline solution containing sodium; Preferably, the alkali solution is selected from at least one of Na2CO3, NaOH and NaHCO3; More preferably, the concentration of the alkali solution is 5-30 g / L, and the pH value is 8-11.

8. The method according to claim 6, wherein: The anaerobic reduction treatment method comprises: using an immobilized sulfur-reducing bacteria filler to reduce sulfate in the sulfate-containing lean liquid into sulfide to obtain the sulfide-absorbing rich liquid B; Preferably, based on the total mass of the immobilized sulfur-reducing bacteria filler, the content of polyvinyl alcohol in the immobilized sulfur-reducing bacteria filler is 5wt%-10wt%, the content of sodium alginate is 1wt%-3wt%, the content of activated carbon is 0.3wt%-0.8wt%, and the content of sulfur-reducing bacteria liquid is 20wt%-50wt%; Preferably, the sulfur-reducing bacteria liquid is selected from at least one of Pseudomonas, Desulfovibrio and Desulfovibrio.

9. The method according to claim 6, wherein: The biological oxidation treatment method comprises using a sulfur oxidizing bacteria group to oxidize the sulfide in the sulfide absorption rich liquid A and / or B into elemental sulfur; Preferably, the sulfur oxidizing bacteria are selected from at least one of Thiobacillus thiosulfurans, Thiobacillus denitrificans and Thiobacillus naples.

10. The method according to any one of claims 5 to 9, wherein: The sulfur-containing gas is selected from at least one of natural gas, oilfield associated gas, synthesis gas and biogas; Preferably, the concentration of hydrogen sulfide in the sulfur-containing gas is 0.1 vol%-5 vol% by volume.

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