Apparatus and method for removing hydrogen sulfide from a sulfur-containing gas

Abstract

The present invention relates to the field of environmental protection and purification technology, and discloses a device and method for removing hydrogen sulfide from sulfur-containing gas, wherein the device includes a packed absorption tower, a biological aerobic reactor, and a lean liquid pump; a sprayer is provided on the top of the packed absorption tower for spraying alkaline solution to convert hydrogen sulfide in the sulfur-containing gas into sulfide; a sulfur-oxidizing bacteria group is provided in the biological aerobic reactor for oxidizing sulfide into elemental sulfur and obtaining a lean liquid containing sulfate; the packed absorption tower is also filled with a fixed sulfur-reducing bacteria group filler for reducing sulfate in the sulfate-containing lean liquid returned by the lean liquid pump into sulfide. The device and method solve the problem of sulfate accumulation, completely convert the sulfur-containing gas into elemental sulfur without discharging sulfate waste liquid, while increasing the yield of elemental sulfur, maintaining system stability, and enhancing the desulfurization effect. 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%.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental protection and purification, and particularly relates to a device and method for removing hydrogen sulfide from a sulfur-containing gas. BACKGROUND

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

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

[0004] The current principle of gas biological desulfurization and sulfur recovery is that the alkali solution chemically absorbs hydrogen sulfide in the gas phase, and under aerobic conditions and the biological catalysis of sulfur-oxidizing bacteria, the sulfide is biologically oxidized to elemental sulfur, and the alkali solution is regenerated. Under the optimal conditions of controlling the redox potential, the yield of elemental sulfur is generally 80-85% using the current sulfur-oxidizing bacteria, and more than 10% of the elemental sulfur is converted into sulfate and enters the desulfurization system, which, over a long period of operation, causes system acidification and seriously affects the desulfurization efficiency. To prevent the accumulation of sulfate, a small continuous stream is drawn from the biological reactor and an alkali solution (such as sodium hydroxide, sodium carbonate or sodium bicarbonate) is added for replenishment. The regular discharge of the sulfate waste solution causes 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 the sulfate waste solution produced by the biological desulfurization process is to evaporate and crystallize the solution in a three-effect evaporator to produce sodium sulfate, which is sold, and basically no wastewater is discharged. However, the evaporation and crystallization process brings problems such as high equipment investment and operating energy consumption costs, which do not meet the current requirements of the energy-saving and environmental protection industry.

[0006] Therefore, the sulfur resource is recovered from the sulfate waste liquid, so as to achieve the maximum recovery of elemental sulfur, realize the closed loop of biological desulfurization, standard emission of waste gas and near zero emission of waste liquid, and become the important task to be solved in line with the current national environmental protection industry development concept and the purpose of national ecological civilization construction. SUMMARY

[0007] The present application aims to overcome the problems of the prior art, such as the accumulation of sulfates during the biological desulfurization treatment of sulfur-containing gas, the serious loss of elemental sulfur caused by the discharge of sulfate waste liquid, the low desulfurization efficiency, and the low yield of elemental sulfur, and provides a device and method for removing hydrogen sulfide from sulfur-containing gas.

[0008] To achieve the above-mentioned purpose, the present application provides a device for removing hydrogen sulfide from sulfur-containing gas, wherein the device comprises a packed tower, a biological aerobic reactor and a lean liquid pump.

[0009] The packed tower is provided with a sprayer at the top, which is used to spray lye to convert hydrogen sulfide in the sulfur-containing gas into sulfide.

[0010] The biological aerobic reactor is provided with a sulfur-oxidizing bacterial population, which is used to oxidize the sulfide into elemental sulfur and obtain a sulfate-containing lean liquid.

[0011] The packed tower is also filled with immobilized sulfur-reducing bacterial population filler, which is used to reduce the sulfates in the sulfate-containing lean liquid returned by the lean liquid pump into sulfide.

[0012] The present application provides a method for removing hydrogen sulfide from sulfur-containing gas, which comprises chemical absorption, biological oxidation treatment and anaerobic reduction treatment of the sulfur-containing gas in the device of 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 0.1vol% to 5vol% by volume.

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

[0016] (1) The present application solves the problem of accumulation of sulfates by adding immobilized sulfur-reducing bacteria carrier as packing in the absorption tower to improve gas-liquid mass transfer and sulfate reduction effect, strictly controlling the dissolved oxygen and oxidation-reduction potential in the biological aerobic reactor, and completely converting the sulfur-containing gas into elemental sulfur, without increasing the complexity of equipment and system, improving the yield of elemental sulfur, maintaining system stability, strengthening desulfurization effect, and reducing the H2S content in the purified gas to less than 10 mg / m 3 , and the generation rate of elemental sulfur is greater than 98%.

[0017] (2) The present application replaces the traditional packing in the absorption tower with immobilized sulfur-reducing bacteria, and when the desulfurization liquid containing sulfates is circulated to the absorption tower, the sulfates are reduced to sulfides under the action of sulfur-reducing bacteria, thereby solving the problems of sulfate accumulation and waste liquid discharge.

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

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

[0020] BRIEF DESCRIPTION OF DRAWINGS

[0021] 1, sulfur-containing gas 2, purified gas after desulfurization 3, air

[0022] 11, packed absorption tower 12, rich liquid pump 13, biological aerobic reactor

[0023] 14, settling tank 15, centrifuge 16, lean liquid pump

[0024] 17, immobilized reducing bacteria group packing DETAILED DESCRIPTION

[0025] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values which are understood to encompass values approximating these ranges and values. For ranges of values, the endpoints of the ranges are combined with the individual points to form new ranges which are also within the scope of the present disclosure.

[0026] To achieve the above-mentioned purpose, the first aspect of the present application 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] The filler absorption tower is provided with a sprayer at the top, which sprays lye to convert hydrogen sulfide in the sulfur-containing gas into sulfide.

[0028] The biological aerobic reactor is provided with a sulfur-oxidizing bacteria group, which is used to oxidize the sulfide into elemental sulfur and obtain a lean liquid containing sulfates.

[0029] The filler absorption tower is also filled with immobilized sulfur-reducing bacteria group filler, which is used to reduce the sulfates in the lean liquid returned by the lean liquid pump into sulfide.

[0030] In the present application, the immobilized sulfur-reducing bacteria group 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 group filler, the content of polyvinyl alcohol 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 application, the sulfur-reducing bacteria liquid is selected from at least one of Pseudomonas, Desulfovibrio and Desulfococcus. The above-mentioned bacteria can be commercially available.

[0032] In the present application, the sulfur-oxidizing bacteria group is selected from at least one of Thiobacillus thiooxidans, Thiobacillus denitrificans and Thiobacillus neapolitanus. The above-mentioned bacteria can be commercially available.

[0033] In the present application, the filler absorption tower is provided with a gas outlet at the top and a gas inlet and a liquid outlet at the bottom. The gas containing hydrogen sulfide enters from the gas inlet at the lower end of the tower body, forms countercurrent contact with the lye flowing downward in the middle of the tower body, the hydrogen sulfide in the gas is absorbed, and the purified gas is discharged from the gas outlet at the upper end of the tower body.

[0034] In the present application, the position where the sulfur-containing gas enters the filler absorption tower is not particularly limited, for example, the gas inlet can be arranged at the upper end of the filler absorption tower, or at the lower end of the filler absorption tower, preferably, the sulfur-containing gas enters from the gas inlet at the lower end of the filler absorption tower.

[0035] In the present application, when the sulfur-containing gas enters from the gas inlet at the lower end of the filler absorption tower, the sulfur-containing gas is more fully countercurrently contacted with the lye sprayed at the top of the filler absorption tower, and the reaction and absorption are more complete.

[0036] According to some embodiments of the present application, the biological aerobic reactor is an air-lift internal circulation biological reactor, which is internally provided with an aeration distributor, so that the dissolved oxygen content in the biological aerobic reactor is 0.3-1.0mg / L.

[0037] In the present application, the biological aerobic reactor is further provided with a dissolved oxygen meter inside, which is used to monitor the dissolved oxygen content in the biological aerobic reactor, and the skilled person adjusts the aeration amount by controlling the fan outside the biological aerobic reactor according to the actual dissolved oxygen content, so that the dissolved oxygen content is within the normal range, ensuring the normal growth of the sulfur-oxidizing bacteria group in the biological aerobic reactor, effectively inhibiting the generation of sulfate, and at the same time improving the conversion efficiency of sulfide.

[0038] According to some embodiments of the present application, the biological aerobic reactor is further provided with a fan and a gas flow meter outside, so that the ratio of the amount of substance of O2 and S 2- in the biological aerobic reactor is 0.7-1, and the oxidation-reduction potential is -400 mV to -250 mV.

[0039] In the present application, the amount of air (oxygen) is controlled by the fan, and the content of hydrogen sulfide is controlled by the raw material gas flow meter, so as to control the ratio of the amount of substance of oxygen and sulfide. The oxidation-reduction potential is jointly reflected by various reducing and oxidizing substances in the solution, such as S 2- which has strong reducing property, and O2 which has oxidizing property. By controlling the amount of air, the oxidation-reduction potential value can be adjusted.

[0040] In the present application, the biological aerobic reactor is further provided with a thermometer, a pH meter and a conductivity meter inside, so that the temperature in the biological aerobic reactor is 25-40℃, the pH value is 8-11, and the conductivity value is 35-60 mS / cm.

[0041] In the present application, by installing online detection instruments in the biological aerobic reactor, the automatic control of key parameters such as temperature, pH value, ORP value, DO value and conductivity value in the biological reactor is realized, so that the dissolved oxygen content, nO2 / nS 2- value and oxidation-reduction potential in the biological aerobic reactor are within the above-mentioned limited range, the sulfur-oxidizing bacteria group has high concentration and high activity, the sulfide is more efficiently converted into elemental sulfur, the generation rate of elemental sulfur is improved, and the generation of sulfate by-products is minimized, so as to realize the efficient and stable operation of the biological desulfurization process.

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

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

[0044] In the present application, the rich liquid absorbing hydrogen sulfide is pressed into the biological aerobic reactor from the water inlet by the rich liquid pump and flows out from the overflow port to the settling tank.

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

[0046] In the present invention, Figure 1 As shown, sulfur-containing gas 1 enters a packed absorption tower 11 (which also contains immobilized sulfur-reducing bacteria packing 17) from bottom to top. After counter-contact and absorption with alkaline solution sprayed from the top of the tower (regenerated alkaline solution containing sulfate circulated back from a lean solution pump 16), the alkaline solution converts hydrogen sulfide in the sulfur-containing gas 1 into sulfide, which then flows out of the packing from top to bottom to form a sulfide-absorbing rich liquid. Desulfurized purified gas 2 is discharged from the top outlet of packed absorption tower 11. The sulfide-absorbing rich liquid is pumped into the water inlet of a bioaerobic reactor 13 from the bottom of packed absorption tower 11 via a rich liquid pump 12. Air 3 enters the bioaerobic reactor 13 through a ventilation pipe at the bottom of the bioaerobic reactor 13. Under air aeration and the biocatalytic action of the sulfur-oxidizing bacteria, the soluble sulfide in the sulfide-absorbing rich liquid is converted into elemental sulfur and sulfate as a byproduct, producing a regenerated liquid containing sulfur and sulfate. The regenerated liquid flows through the overflow port of the biological aerobic reactor 13 into the sedimentation tank 14 for sedimentation to obtain a supernatant and a settled sulfur solution. The settled sulfur solution is sent to the centrifuge 15 through the discharge port of the sedimentation tank 14, where solid-liquid separation is achieved to obtain biosulfur. The supernatant (containing sulfate and alkali liquor) is returned to the packed absorption tower 11 via the lean liquid pump 16 for recycling. The sulfate therein is reduced to sulfide by the immobilized sulfur-reducing bacteria filler 17 loaded in the packed absorption tower 11, and then merged into the rich liquid that absorbs the sulfide to recover elemental sulfur, thereby solving the problems of sulfate accumulation and waste liquid discharge.

[0047] A 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 apparatus 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 sulphate-containing lean liquid to anaerobic reduction treatment in a packed tower included in the device to obtain a sulphide absorption rich liquid B;

[0052] (4) subjecting the sulphide absorption rich liquid B to step (2) to obtain elemental sulphur.

[0053] According to some embodiments of the present application, the method of chemical absorption comprises: converting hydrogen sulphide in the sulphur-containing gas into sulphide by using an alkali solution to obtain a sulphide absorption rich liquid A.

[0054] Preferably, the alkali solution is a sodium-containing alkaline solution; 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 application, the method of anaerobic reduction treatment comprises: reducing sulphate in the sulphate-containing lean liquid into sulphide by using an immobilized sulphide-reducing bacterial population filler to obtain the sulphide absorption rich liquid B.

[0056] In the present application, the source of the immobilized sulphide-reducing bacterial population filler is not particularly limited and can be commercially available or self-prepared. The immobilized sulphide-reducing bacterial population filler is prepared by cross-linking embedding method, such as a specific preparation method: weighing a certain amount of polyvinyl alcohol, sodium alginate and activated carbon in a container, adding a certain amount of sterile water, heating and dissolving to a paste, cooling to about 40℃, quickly adding a certain amount of sulphide-reducing bacterial solution, mixing and stirring, using a syringe to draw the mixed solution and drop it into a 2% calcium chloride saturated boric acid solution for cross-linking and molding.

[0057] Preferably, based on the total mass of the immobilized sulphide-reducing bacterial population filler, the content of polyvinyl alcohol in the immobilized sulphide-reducing bacterial population 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 sulphide-reducing bacterial solution is 20wt%-50wt%.

[0058] In the present application, when the content of each substance of the immobilized sulphide-reducing bacterial population filler meets the above range, the performance of the immobilized small balls is excellent, and the sulphate degradation rate is above 85%; when the content of each substance of the immobilized sulphide-reducing bacterial population filler does not meet the above range, the mechanical and mass transfer performance of the immobilized small balls will be poor and the desulphurization rate will be low.

[0059] Preferably, the sulphide-reducing bacterial solution is selected from at least one of Pseudomonas, Desulfovibrio and Desulfoarcus.

[0060] According to some embodiments of the present invention, the biological oxidation treatment method includes using a sulfur-oxidizing bacterial community 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% to 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, the specific operation method comprising:

[0065] The alkali concentration in the packed absorption tower 11 is 15-25 g / L, and the immobilized reducing bacteria filler 17 includes 5 wt%-10 wt% of polyvinyl alcohol, 1 wt%-3 wt% of sodium alginate, 0.3 wt%-0.8 wt% of activated carbon, and 20 wt%-50 wt% of a sulfur-reducing bacteria solution (the sulfur-reducing bacteria solution is selected from a composite bacteria of desulfurizing Vibrio and desulfurizing Campylobacter); in the bioaerobic reactor 13, the sulfur-oxidizing bacteria are selected from at least one of Thiobacillus thiosulfuri, Thiobacillus denitrificans, and Thiobacillus Naples, and the dissolved oxygen content is 0.3 mg / L-1 mg / 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 the total sulfur element 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 hydrogen sulfide content in the sulfur-containing gas is 0.1% (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 solution (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 thiosulfuri and Thiobacillus denitrificans, the dissolved oxygen content is 0.3mg / L, nO2 / nS 2- The value is 0.75, 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 hydrogen sulfide content in the sulfur-containing gas is 0.1% (volume fraction), the alkali solution concentration in the packed absorption tower 11 is 20g / L, the immobilized reducing bacteria filler 17 includes 8.5wt% polyvinyl alcohol, 2wt% sodium alginate, 0.6wt% activated carbon, and 40wt% sulfur-reducing bacteria solution (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the bioaerobic 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 production 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 solution (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the bioaerobic reactor 13, the sulfur-oxidizing bacteria are selected from a composite flora of Thiobacillus thiosulfurans and Thiobacillus napolitans, 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 measured to be 1mg / m 3 , the elemental sulfur production rate is 98.5%.

[0078] Example 4

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

[0080] The content of hydrogen sulfide in the sulfur-containing gas is 0.5% (volume fraction), the concentration of lye in the filler absorption tower 11 is 20 g / L, the immobilized reducing bacteria group filler 17 includes 8.5 wt% of polyvinyl alcohol, 2 wt% of sodium alginate, 0.6 wt% of activated carbon, and 40 wt% of sulfur-reducing bacteria liquid (a complex bacteria group of Desulfovibrio desulfuricans and Desulfuricoccus desulfuricans); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria group is a complex bacteria group of Thiobacillus thiooxidans and Thiobacillus denitrificans, the dissolved oxygen content is 0.5 mg / L, the nO2 / nS 2- value is 0.85, and the ORP (Oxidation-Reduction Potential) is -300 mV. The content of hydrogen sulfide in the purified gas 2 is measured to be 0 mg / m 3 , and the elemental sulfur production rate is 99.6%.

[0081] Example 5

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

[0083] The content of hydrogen sulfide in the sulfur-containing gas is 1% (volume fraction), the concentration of lye in the filler absorption tower 11 is 20 g / L, the immobilized reducing bacteria group filler 17 includes 7 wt% of polyvinyl alcohol, 2.5 wt% of sodium alginate, 0.4 wt% of activated carbon, and 20 wt% of sulfur-reducing bacteria liquid (a complex bacteria group of Desulfovibrio desulfuricans and Desulfuricoccus desulfuricans); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria group is a complex bacteria group of Thiobacillus thiooxidans and Thiobacillus denitrificans, the dissolved oxygen content is 0.6 mg / L, the nO2 / nS 2- value is 0.83, and the ORP (Oxidation-Reduction Potential) is -350 mV. The content of hydrogen sulfide in the purified gas 2 is measured to be 3 mg / m 3 , and the elemental sulfur production rate is 99.8%.

[0084] Example 6

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

[0086] The content of hydrogen sulfide in the sulfur-containing gas is 1% (volume fraction), the concentration of lye in the filler absorption tower 11 is 25 g / L, the immobilized reducing bacteria group filler 17 includes 8.5 wt% of polyvinyl alcohol, 2 wt% of sodium alginate, 0.6 wt% of activated carbon, and 40 wt% of sulfur-reducing bacteria liquid (a complex bacteria group of Desulfovibrio desulfuricans and Desulfuricoccus desulfuricans); in the biological aerobic reactor 13, the sulfur-oxidizing bacteria group is a complex bacteria group of Thiobacillus thiooxidans and Thiobacillus denitrificans, the dissolved oxygen content is 0.8 mg / L, the 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 production 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 20 g / L, the immobilized reducing bacteria filler 17 includes 7 wt% of polyvinyl alcohol, 2.5 wt% of sodium alginate, 0.4 wt% of activated carbon, and 20 wt% of sulfur-reducing bacteria solution (a composite flora of desulfurizing Vibrio and desulfurizing Campylobacter); in the bioaerobic reactor 13, the sulfur-oxidizing bacteria are a composite flora of denitrifying Thiobacillus and Naples Thiobacillus, the dissolved oxygen content is 0.6 mg / 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 measured to be 8mg / m 3 , the elemental sulfur production 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 Thiobacillus thiosulfuri and Thiobacillus denitrificans, 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 measured to be 5mg / m 3 , the elemental sulfur production 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 production rate is 88.3%.

[0095] Comparative Example 2

[0096] The same method as in Example 5 was used except that the dissolved oxygen content in the bioaerobic reactor 13 was 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 13mg / m 3 , the elemental sulfur production rate is 93.2%.

[0097] Comparative Example 3

[0098] The same method as in Example 5 is used except that the packed absorption tower 11 is filled with ball ring packing, and 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 measured to be 21mg / m 3 , the elemental sulfur production 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 bioaerobic 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 production rate is 87.5%.

[0101] Comparative Example 5

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

[0103] The data of Examples 1-8 show 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 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 3The generation rate of elemental sulfur is greater than 98%. Comparative Example 1 changes the filler in the filler 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 filler in the filler 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; and Comparative Example 5 changes the material content of the immobilized sulfur-reducing bacteria in the filler 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 application integrates the sulfur oxidation and sulfur reduction processes into the same system by using the chemical absorption-biological oxidation-anaerobic reduction coupling technology, completely converts the sulfur-containing gas into elemental sulfur, solves the problem of sulfate accumulation, increases the yield of elemental sulfur without increasing the complexity of the equipment and system, and realizes the closed-loop cycle of biological desulfurization without waste liquid discharge.

[0105] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. An apparatus for removing hydrogen sulfide from a sulfur-containing gas, comprising: The device comprises a filler absorption tower, a biological aerobic reactor and a lean liquid pump; The filler absorption tower is provided with a sprayer at the top, which sprays lye to convert hydrogen sulfide in the sulfur-containing gas into sulfide; The biological aerobic reactor is provided with a sulfur-oxidizing bacteria group, which oxidizes the sulfide into elemental sulfur and obtains lean liquid containing sulfates; The filler absorption tower is also filled with immobilized sulfur-reducing bacteria group filler, which reduces sulfates in the lean liquid returned by the lean liquid pump into sulfide.

2. The apparatus of claim 1, wherein, The biological aerobic reactor is a gas-lift internal circulation biological reactor, which is provided with an aeration distributor at the bottom, so that the dissolved oxygen content in the biological aerobic reactor is 0.3-1 mg / L.

3. The apparatus of claim 2, wherein, The biological aerobic reactor is externally provided with a fan and a gas flow meter, so that the ratio of the amounts of substance of O2 and S 2- in the biological aerobic reactor is 0.7-1, and the oxidation-reduction potential is -400 mV to -250 mV.

4. The apparatus of any of claims 1-3, wherein, The device further comprises a rich liquid pump, a sedimentation tank and a centrifuge.

5. The apparatus of claim 4, wherein, The rich liquid pump is connected to the liquid outlet of the filler 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 liquid outlet of the sedimentation tank is connected to the centrifuge.

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

7. The method of claim 6, wherein, The method comprises the following steps: (1) The sulfur-containing gas is subjected to chemical absorption in the filler absorption tower included in the device to obtain sulfide absorption rich liquid A; (2) The sulfide absorption rich liquid A is subjected to biological oxidation treatment in the biological aerobic reactor included in the device to obtain elemental sulfur and lean liquid containing sulfates; (3) The lean liquid containing sulfates is subjected to anaerobic reduction treatment in the filler absorption tower included in the device to obtain sulfide absorption rich liquid B; (4) The sulfide absorption rich liquid B is subjected to step (2) to obtain elemental sulfur.

8. The method of claim 7, wherein, The method of chemical absorption comprises converting hydrogen sulfide in the sulfur-containing gas into sulfide by using lye to obtain sulfide absorption rich liquid A.

9. The method of claim 8, wherein, The lye is a sodium-containing alkaline solution.

10. The method of claim 9, wherein, The lye is selected from at least one of Na2CO3, NaOH and NaHCO3.

11. The method of claim 10, wherein, The concentration of the lye is 5-30 g / L, and the pH value is 8-11.

12. The method of claim 7, wherein, The method of anaerobic reduction treatment comprises reducing sulfates in the lean liquid containing sulfates into sulfide by using immobilized sulfur-reducing bacteria group filler to obtain the sulfide absorption rich liquid B.

13. The method of claim 12, wherein, Based on the total mass of the immobilized sulfur-reducing bacteria group filler, the content of polyvinyl alcohol in the immobilized sulfur-reducing bacteria group 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%.

14. The method of claim 13, wherein, The sulfur-reducing bacteria liquid is selected from at least one of Pseudomonas, Desulfovibrio and Desulfococcus.

15. The method of claim 7, wherein, The method of biological oxidation treatment comprises oxidizing sulfide in the sulfide absorption rich liquid A and / or B into elemental sulfur by using a sulfur-oxidizing bacteria group.

16. The method of claim 15, wherein, The sulfur-oxidizing bacteria group is selected from at least one of Thiobacillus thiooxidans, Thiobacillus denitrificans and Thiobacillus neapolitanus.

17. The method of any of claims 7-16, wherein, The sulphur-containing gas is selected from at least one of natural gas, oilfield associated gas, synthesis gas and biogas.

18. The method of claim 17, wherein, The concentration of hydrogen sulphide in the sulphur-containing gas is 0.1 vol% to 5 vol% by volume.

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