Process and system for efficient desulfurization of fuel gas

Abstract

The application discloses a fuel gas efficient desulfurization process method and system, and relates to the field of fuel gas desulfurization technology.The process method comprises the following steps: feeding fuel gas raw material into a hydrodesulfurization tower filled with a hydrodesulfurization catalyst, and then feeding the treated fuel gas into an absorption tower containing an absorption liquid, and the obtained absorption liquid is subjected to solid-liquid separation, and then the liquid part is sent into a microbial oxidation tower containing a ferrous iron thiobacillus liquid, so as to complete the desulfurization treatment of the fuel gas.The application fully utilizes the respective advantages of the hydrodesulfurization and microbial desulfurization processes, achieves the purpose of efficiently removing organic sulfur in the fuel gas, and has high desulfurization efficiency and a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of fuel gas purification technology, specifically relating to a high-efficiency desulfurization process and system for fuel gas. Background Technology

[0002] Fuel gas is both a byproduct of refining and chemical production and a valuable energy source. In refineries, fuel gas powers furnaces and boilers in various production units. However, due to its complex origins and varied composition, fuel gas often has a high sulfur content. Direct combustion of fuel gas can lead to pollution and equipment corrosion. While there are currently no mandatory quality standards for fuel gas, with increasingly stringent environmental requirements and improved environmental laws, it is essential to enhance the control of total sulfur content in fuel gas.

[0003] The processing volume of sulfur-containing and high-sulfur crude oil is increasing. Refinery dry gas, a byproduct of petroleum processing, mainly contains impurities such as H2, N2, H2S, CH4, C2H4, C2H6, C3H6, C3H8, CO, CO2, RSH, COS, and small amounts of C4, C5, and H2O. After desulfurization with organic alcohol amines (N-methyldiethanolamine), it is used as fuel gas for heating furnaces. However, this type of gas also contains a significant amount of olefins and organic sulfur. The olefin content is generally 6%–12%, sometimes exceeding 20%, and the organic sulfur content is around 200 μg / g, with complex sulfur forms. The complexity of organic sulfur forms makes the purification of this gas quite difficult, directly affecting its effective utilization. Refinery gas refining is essentially a process of removing inorganic and organic sulfur, primarily aiming to remove sulfur-containing compounds from fuel gas. This not only reduces equipment corrosion during gas processing and is beneficial for environmental protection but also facilitates the chemical utilization of gas products.

[0004] Gas desulfurization methods are generally divided into dry desulfurization and wet desulfurization. Dry desulfurization removes H2S by passing the gas through a bed of solid adsorbents. Commonly used solid adsorbents include sponge iron, activated carbon, alumina, zeolite, and molecular sieves. Its mechanism is mainly gas-solid physical adsorption. It is only suitable for treating gases containing trace amounts of H2S and can completely remove H2S. However, because this method is an intermittent operation, it suffers from bulky equipment, high investment, low throughput, difficulty in adsorbent regeneration, and significant development challenges, which severely restricts the development and application of this technology. Wet desulfurization uses liquid desulfurizing agents to remove hydrogen sulfide and carbon disulfide, among other sulfides, from petroleum gas. Based on the composition of the liquid desulfurizing agent, it can be divided into chemical absorption and physical absorption methods. Alkylamine solvents are widely used chemical absorbents. Another method using polyol ether solutions as desulfurizing agents is the physical absorption method (known internationally as the Selexol method, and domestically as the NHD method after improvement). The mechanism of physical absorption is mainly based on the principle of "like dissolves like," where sulfides are removed by dissolving in a solvent. However, due to the large solvent ratio, low desulfurization efficiency, high investment cost, and large footprint of physical absorption, such devices are gradually decreasing in number.

[0005] Organic sulfur compounds (carbonyl sulfur, thiols, thioethers, etc.) are difficult to remove by absorption. They are typically converted to inorganic sulfur (H₂S) via hydrocatalysis before removal. Hydrodesulfurization is a widely used desulfurization method worldwide, with mature technology. Few other feasible liquid fuel desulfurization methods have replaced this traditional method. Traditional natural gas hydrodesulfurization catalysts typically use Co-Mo or Fe-Mo based active components; the support is generally a porous inorganic oxide, usually one or more of alumina, silica, zirconium dioxide, or aluminosilicates; and one or more of the elements F, Si, P, Mn, Ca, and Zn are commonly used as co-catalyst components. In heterogeneous catalysis, the form in which the active components exist on the support surface directly affects the catalyst activity. The form in which the active components exist is closely related to the composition ratio of the impregnation solution. To prepare a highly active hydrodesulfurization catalyst, the hydrogenation components should also have a reasonable atomic ratio. This is because there is an optimal value for the metal content of the catalyst, and the reasonable atomic ratio is directly related to the composition ratio of the impregnation solution.

[0006] In addition, microbial desulfurization, which has emerged in recent years, is a new technology to replace chemical desulfurization. It overcomes many shortcomings of chemical methods for removing inorganic sulfur (H2S) and has advantages such as high H2S removal rate (up to 100%), low operating cost, operation at ambient temperature and pressure (approximately one-third the operating cost of conventional wet desulfurization), zero emissions, no secondary pollution, and high purity of by-product sulfur. Thiobacillus ferrooxidans (T. ferrooxidans) has been extensively studied for its biological characteristics and has become one of the main bacterial species for leaching various metals in industry. It has also been widely researched and applied in various fields such as coal desulfurization, domestic sewage purification, and the treatment of industrial and petroleum waste gases. Biological desulfurization technology is a new technology that uses aerobic bacteria to remove sulfur atoms from sulfur-containing compounds at ambient temperature and pressure. This technology is considered a potential alternative to conventional desulfurization technologies in oil refineries.

[0007] How to combine hydrodesulfurization and microbial desulfurization to improve desulfurization efficiency is a topic worthy of in-depth research. Existing technologies, such as patent document CN921017634, provide a method for deep desulfurization of fossil fuels, but it does not involve the specific preparation of the hydrodesulfurization catalyst or the selection of a specific Rhodococcus roseus bacteria.

[0008] Therefore, this invention is proposed. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a high-efficiency desulfurization process and system for fuel gas, which fully utilizes the advantages of both hydrodesulfurization and microbial desulfurization processes to achieve efficient removal of organic sulfur from fuel gas.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a method for efficient desulfurization of fuel gas, comprising the following steps: sending the fuel gas, which has been successively treated by a hydrodesulfurization catalyst and an absorbent, to a solution of *Thiobacillus ferrooxidans* for further treatment.

[0012] As a preferred embodiment of the technical solution of the present invention, the process method specifically includes the following steps:

[0013] The fuel gas feedstock is fed into a hydrodesulfurization tower filled with a hydrodesulfurization catalyst. The treated fuel gas is then fed into an absorption tower containing an absorbent liquid. After solid-liquid separation, the liquid portion of the absorbent liquid is sent to a microbial oxidation tower containing a solution of *Thiobacillus ferrooxidans*, thus completing the desulfurization treatment of the fuel gas.

[0014] As a preferred embodiment of the technical solution of the present invention, the preparation of the hydrodesulfurization catalyst includes the following steps:

[0015] (1) Prepare a mixed solution containing cobalt source and molybdenum source;

[0016] (2) After grinding and sieving the alumina carrier, add it to the mixed solution obtained in step (1), mix evenly, and then perform ultrasonic impregnation treatment to obtain the impregnation solution.

[0017] (3) The impregnation solution obtained in step (2) is dried and calcined to obtain catalyst powder;

[0018] (4) The catalyst powder obtained in step (3) is mixed with binder and deionized water to prepare a slurry. The slurry is then shaped, dried and calcined to obtain the hydrodesulfurization catalyst.

[0019] As a preferred embodiment of the technical solution of the present invention, in step (1), the cobalt source is cobalt nitrate hexahydrate, the molybdenum source is ammonium molybdate tetrahydrate, and the atomic molar ratio of cobalt to molybdenum is 1:1 to 2.

[0020] As a preferred embodiment of the technical solution of the present invention, in step (2), the mass ratio of cobalt source to alumina is 1:1 to 2; and the ultrasonic impregnation treatment time is 0.5 to 4 hours.

[0021] As a preferred embodiment of the technical solution of the present invention, in step (3), the calcination temperature is 480-520℃ and the calcination time is 2-12h.

[0022] As a preferred embodiment of the technical solution of the present invention, in step (4), the calcination temperature is 420-500℃ and the calcination time is 2-12h.

[0023] As a preferred embodiment of the technical solution of the present invention, the process conditions in the hydrodesulfurization tower are as follows: reaction temperature of 220–300℃, reaction pressure of 0.1–0.5 MPa, and gas hourly space velocity of 200–1000 h⁻¹. -1 .

[0024] As a preferred embodiment of the present invention, the absorbent is Fe2(SO4)3 absorbent with a concentration of 5-20 g / L.

[0025] As a preferred embodiment of the technical solution of the present invention, the process conditions of the absorption tower are as follows: absorption temperature of 35-45℃, gas-liquid ratio of 5-15:1, and gas hourly space velocity of 200-1000 h⁻¹. -1 .

[0026] As a preferred embodiment of the technical solution of the present invention, the oxygen-to-sulfur ratio of the microbial oxidation tower is 1.2 to 1.8, and the reaction temperature is 25 to 35°C.

[0027] Secondly, the present invention also provides a system for implementing the above-mentioned efficient desulfurization process for fuel gas, including a hydrodesulfurization tower, the bottom of which is connected to an absorption tower via a pipeline, the lower part of which is connected to a separator via a pipeline, and the separator being connected to a microbial oxidation tower via a pipeline.

[0028] As a preferred embodiment of the present invention, the upper part of the microbial oxidation tower is also connected to the tower side of the absorption tower via a pipe.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention combines hydrodesulfurization with microbial desulfurization, fully utilizing the advantages of each process. First, a Co-Mo / Al2O3 catalyst is used to convert organic sulfur in fuel gas into inorganic sulfur (H2S) through hydrodesulfurization. Then, microbial desulfurization is used to completely remove the inorganic sulfur (H2S) from the fuel gas. This addresses the practical problems existing in traditional H2S removal technologies by utilizing the indirect oxidation effect of *Thiobacillus ferrooxidans* to organically combine chemical desulfurization and microbial catalytic oxidation regeneration of the desulfurization liquid, thereby achieving low-cost, resource-efficient, and harmless treatment of sulfides in fuel gas. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the process system of the present invention.

[0032] The components include: 1. Hydrodesulfurization tower; 2. Absorption tower; 3. Separator; 4. Microbial oxidation tower; 5. Microdroplet nozzle; and 6. Microbubble generator. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be emphasized that, unless otherwise specified in the examples, the conditions should be performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. The *Thiobacillus ferrooxidans* solution was purchased from BioBioBio.

[0035] This invention provides a high-efficiency desulfurization process for fuel gas, comprising the following steps: sending the fuel gas, which has been sequentially treated by a hydrodesulfurization catalyst and an absorbent, to a solution of *Thiobacillus ferrooxidans* for further treatment.

[0036] In the above technical solution, the fuel gas to be desulfurized is first subjected to hydrodesulfurization, and then to microbial desulfurization. This addresses the current limitations of dry and wet desulfurization technologies in fuel gas desulfurization, which are mostly used for removing inorganic sulfides (H2S). Their effectiveness in removing organic sulfides such as thiols, thioethers, and carbonyl sulfides is generally limited. Furthermore, physicochemical methods for removing inorganic sulfides (H2S) suffer from problems such as high solvent ratios, low desulfurization efficiency, high investment costs, and large land requirements. By organically combining chemical desulfurization (hydrodesulfurization) and microbial catalytic oxidation to regenerate the desulfurization liquid, a green, low-cost, and high-efficiency fuel gas desulfurization and refining can be achieved. Therefore, for difficult-to-remove organic sulfides such as thiols, thioethers, and carbonyl sulfides in fuel gas, hydrodesulfurization technology is needed to convert the organic sulfur in the fuel gas into easily removable inorganic sulfides (H2S). Subsequently, a microbial desulfurization process is used to completely remove the inorganic sulfur (H2S) from the fuel gas, resulting in high removal efficiency.

[0037] More specifically, the above process includes the following steps:

[0038] The fuel gas feedstock is fed into a hydrodesulfurization tower filled with a hydrodesulfurization catalyst. The treated fuel gas is then fed into an absorption tower containing an absorbent liquid. After solid-liquid separation, the liquid portion of the absorbent liquid is sent to a microbial oxidation tower containing a solution of *Thiobacillus ferrooxidans*, thus completing the desulfurization treatment of the fuel gas.

[0039] In the above technical solution, the organic sulfur in the fuel gas is converted into inorganic sulfur in the hydrodesulfurization tower. In the absorption tower, H2S is oxidized into elemental sulfur through absorption and oxidation by the absorbent liquid. The sulfur obtained after solid-liquid separation of the absorbent liquid is recovered to obtain sulfur product. The liquid portion is sent to the microbial oxidation tower, where it is oxidized by the action of *Thiobacillus ferrooxidans* liquid. It can then be reintroduced into the absorption tower to react with H2S, thus achieving the goal of cyclic H2S removal and sulfur recovery. During this cyclic operation, the solution does not deteriorate, no waste is discharged, and no special chemical agents or catalysts are required.

[0040] The hydrodesulfurization catalyst mentioned above can be a commercially available catalyst or a self-made one. As a more preferred technical solution, the hydrodesulfurization catalyst used in this invention is prepared through the following steps:

[0041] (1) Prepare a mixed solution containing cobalt source and molybdenum source;

[0042] (2) After grinding and sieving the alumina carrier, add it to the mixed solution obtained in step (1), mix evenly, and then perform ultrasonic impregnation treatment to obtain the impregnation solution.

[0043] (3) The impregnation solution obtained in step (2) is dried and calcined to obtain catalyst powder;

[0044] (4) The catalyst powder obtained in step (3) is mixed with binder and deionized water to prepare a slurry. The slurry is then shaped, dried and calcined to obtain the hydrodesulfurization catalyst.

[0045] In the above preparation method, the active components of the hydrodesulfurization catalyst are mainly cobalt and molybdenum, and the support is alumina. The loading of the active components can be completed by impregnation treatment.

[0046] In some embodiments, in step (1), the cobalt source is one of cobalt nitrate hexahydrate, cobalt chloride or cobalt acetate, and the molybdenum source is ammonium molybdate tetrahydrate, and the atomic molar ratio of cobalt to molybdenum is 1:1 to 2; more preferably, the atomic molar ratio of cobalt to molybdenum is 1:1.5.

[0047] In some embodiments, in step (2), the mesh size of the grinding sieve can be between 20 and 40 mesh, the mass ratio of cobalt source to alumina is 1:1 to 2, and the ultrasonic impregnation treatment time is 0.5 to 4 hours. It is understood that the ultrasonic impregnation treatment time can be any value from 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, or any value within the above range. More preferably, the ultrasonic impregnation treatment time is 2 hours.

[0048] In some embodiments, in step (3), the calcination temperature is 480–520°C, and the calcination time is 2–12 h. It is understood that the calcination temperature can be any value among 480°C, 485°C, 490°C, 495°C, 500°C, 505°C, 510°C, 515°C, and 520°C, or any value within the range of 480–520°C; the calcination time can be any value among 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h, and 12 h, or any value within the range of 2–12 h. More preferably, the calcination temperature is 500°C, and the calcination time is 5 h.

[0049] In some embodiments, in step (4), the calcination temperature is 420-500°C and the calcination time is 2-12 hours. It is understood that the aforementioned roasting temperature can be any value selected from 420℃, 425℃, 430℃, 435℃, 440℃, 445℃, 450℃, 455℃, 460℃, 465℃, 470℃, 475℃, 480℃, 485℃, 490℃, 495℃, and 500℃, or any value within the range of 420℃ to 500℃; the roasting time can be any value selected from 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h, and 12h, or any value within the range of 2 to 12h. More preferably, the roasting temperature is 450℃, and the roasting time is 4h.

[0050] In some implementations, the process conditions in the hydrodesulfurization tower are: reaction temperature of 220–300°C, reaction pressure of 0.1–0.5 MPa, and gas hourly space velocity of 200–1000 h⁻¹. -1 The above reaction parameters can be flexibly adjusted as needed to match the comprehensive requirements of catalysts, etc. More specifically, the reaction temperature can be any value from 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, 295℃, 300℃, 305℃, 310℃, 315℃, 320℃, or any value within the range of 220℃ to 300℃; similarly, the above reaction pressure can be 0.1MPa, 0.11MPa, 0.12MPa, 0.13MPa, 0.14MPa, 0.15MPa, 0.16MPa, 0.17MPa, 0.18MPa, 0.19MPa, 0.2MPa, 0.21MPa, 0.2... The value is one of the following: 2MPa, 0.23MPa, 0.24MPa, 0.25MPa, 0.26MPa, 0.27MPa, 0.28MPa, 0.29MPa, 0.3MPa, 0.31MPa, 0.32MPa, 0.33MPa, 0.34MPa, 0.35MPa, 0.36MPa, 0.37MPa, 0.38MPa, 0.39MPa, 0.4MPa, 0.41MPa, 0.42MPa, 0.43MPa, 0.44MPa, 0.45MPa, 0.46MPa, 0.47MPa, 0.48MPa, 0.49MPa, or 0.5MPa, or any value within the range of 0.1 to 0.5MPa. More preferably, the reaction temperature is 260°C, the reaction pressure is 0.2 MPa, and the gas hourly space velocity is 500 h⁻¹. -1.

[0051] In some embodiments, the absorbent is Fe2(SO4)3 absorbent with a concentration of 5–20 g / L; it is understood that the concentration of the absorbent can be any value selected from 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L, and 20 g / L, or any value within the aforementioned range; more preferably, it is 10 g / L. In the absorption tower, the process conditions are: absorption temperature of 35–45°C, gas-liquid ratio of 5–15:1, and gas hourly space velocity of 200–1000 h⁻¹. -1 More preferably, the absorption temperature is 40°C, the gas-liquid ratio is 10:1, and the gas hourly space velocity is 500 h⁻¹. -1 In practice, the pH of the absorbent solution during circulation can be adjusted to 8.5.

[0052] In some embodiments, the oxygen-sulfur ratio and some related process parameters are controlled in the microbial oxidation tower, such as an oxygen-sulfur ratio of 1.2 to 1.8 and a reaction temperature of 25 to 35°C. More preferably, the oxygen-sulfur ratio is 1.5 and the reaction temperature is 30°C.

[0053] This invention also provides a system for implementing the above-described efficient desulfurization process for fuel gas, see [link to documentation]. Figure 1 The system includes a hydrodesulfurization tower 1, the bottom of which is connected to an absorption tower 2 via a pipe, the lower part of which is connected to a separator 3 via a pipe, and the separator 3 is connected to a microbial oxidation tower 4 via a pipe.

[0054] In some embodiments, the upper part of the microbial oxidation tower 4 is also connected to the tower side of the absorption tower 2 through a pipe to form a recycling of the absorption liquid.

[0055] It should be noted that a micro-droplet nozzle 5, a type of metal microporous nozzle, can be installed at the inner top of the absorption tower to atomize the liquefied gas into micron-sized micro-droplets; a microbubble generator 6 can be installed at the inner bottom of the absorption tower to disperse the gas entering the absorption tower into micron-sized microbubbles, thereby enhancing the mass transfer contact area between the Fe2(SO4)3 absorbent liquid and the H2S-containing fuel gas in the gas absorption tower and improving the gas-liquid absorption efficiency. The above-mentioned structural components can adopt any form existing in the art, and this invention does not limit their specific structure; the specific structure should be such that it can be implemented by those skilled in the art.

[0056] See further Figure 1 The specific process flow of the present invention is described as follows:

[0057] Fuel gas is passed into hydrodesulfurization tower 1, which is filled with hydrodesulfurization catalyst. Under suitable temperature, pressure, and space velocity, the organic sulfur in the fuel gas is converted into inorganic sulfur (H2S). Subsequently, the fuel gas containing inorganic sulfur (H2S) is sent to absorption tower 2, which contains Fe2(SO4)3 absorbent liquid. 3+ H₂S is oxidized to produce elemental sulfur, Fe 3+ It was also reduced to Fe. 2+ The sulfur-rich absorbent enters separator 3, where solid-liquid separation yields sulfur, which is directly exported. The resulting filtrate is pumped into microbial oxidation tower 4, where *Thiobacillus ferrooxidans* extract removes the Fe from the filtrate. 2+ Catalytic oxidation to Fe 3+ The resulting Fe-containing 3+ The reaction liquid is returned to the absorption tower, where it can react with H2S again, thus achieving the effect of cyclic H2S removal and sulfur recovery.

[0058] The following detailed description of a high-efficiency desulfurization process and system for fuel gas according to the present invention is further illustrated by specific embodiments.

[0059] Example 1

[0060] A method for preparing a hydrodesulfurization catalyst includes the following steps:

[0061] (1) Weigh 10.37g of cobalt nitrate hexahydrate and 66.07g of ammonium molybdate tetrahydrate, and disperse them evenly in 100mL of deionized water to prepare a mixed solution containing the active components;

[0062] (2) Weigh 12g of alumina carrier, then grind it to 20-40 mesh, then add the obtained carrier to the mixed solution obtained in step (1), mix evenly and then ultrasonically impregnate for 2 hours to obtain impregnation solution.

[0063] (3) The impregnation solution obtained in step (3) is dried at 110°C for 24 hours. After drying, it is calcined at 500°C for 5 hours to obtain catalyst powder.

[0064] (4) The catalyst powder obtained in step (3) is mixed with 3.5 wt% adipic acid binder and deionized water to prepare a slurry. The slurry is shaped and dried at 105°C for 12 h, and then calcined at 450°C for 4 h to obtain the hydrodesulfurization catalyst.

[0065] Example 2

[0066] A system for efficient desulfurization of fuel gas includes a hydrodesulfurization tower 1, the bottom of which is connected to an absorption tower 2 via a pipeline, the lower part of which is connected to a separator 3 via a pipeline, and the separator 3 is connected to a microbial oxidation tower 4 via a pipeline.

[0067] The upper part of the microbial oxidation tower 4 is also connected to the tower side of the absorption tower 2 through a pipe to form a cycle of absorption liquid.

[0068] Example 3

[0069] A high-efficiency desulfurization process for fuel gas includes the following steps:

[0070] Preparation of simulated fuel gas: The fuel gas is prepared according to the following content in molar amounts: methane 62%, ethane 20%, propane 2%, isobutane 1%, ethylene 3%, propylene 1.5%, isobutene 0.5%, H2 10%, H2S 5ppm, COS 25ppm, CH3SH 15ppm, CH3CH2SH 5ppm (total sulfur: 50ppm);

[0071] The hydrodesulfurization catalyst prepared in Example 1 was loaded into hydrodesulfurization tower 1, and then... Figure 1 After the equipment was set up, the process conditions for hydrodesulfurization tower 1 were controlled as follows: reaction temperature 260℃, reaction pressure 0.2MPa, and gas hourly space velocity 500h⁻¹. -1 The process conditions for controlling absorption tower 2 are: gas hourly space velocity 500 h⁻¹ -1 The Fe2(SO4)3 absorbent concentration is 10 g / L, the circulating absorbent pH is 8.5, the absorption temperature is 40℃, and the gas-liquid ratio in the absorbent tower is 10:1. The process conditions for the microbial oxidation tower 4 are adjusted as follows: oxygen-sulfur ratio 1.5, reaction temperature 30℃ (at this time, the ORP of the desulfurization liquid is -390 to -300 mV, which is the optimal operating state, forming an emulsion).

[0072] After the aforementioned simulated fuel gas was introduced, the H2S content in the purified fuel gas was measured to be 1 ppm.

[0073] Obviously, the desulfurization process provided by this invention fully utilizes the advantages of both hydrodesulfurization and microbial desulfurization processes. First, a Co-Mo / Al2O3 catalyst is used to convert organic sulfur in the fuel gas into inorganic sulfur (H2S) through hydrodesulfurization. Then, microbial desulfurization completely removes the inorganic sulfur (H2S) from the fuel gas, thus achieving highly efficient desulfurization of the fuel gas. The above embodiments illustrate the technical concept of this invention, but this invention is not limited to the above embodiments, meaning that this invention does not necessarily depend on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of individual raw materials for the product of this invention, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A high-efficiency desulfurization process for fuel gas, characterized in that, The process includes the following steps: the fuel gas, which has been successively treated by a hydrodesulfurization catalyst and an absorbent, is sent to a solution of *Thiobacillus ferrooxidans* for further treatment.

2. The efficient desulfurization process for fuel gas according to claim 1, characterized in that, The process method specifically includes the following steps: The fuel gas feedstock is fed into a hydrodesulfurization tower filled with a hydrodesulfurization catalyst. The treated fuel gas is then fed into an absorption tower containing an absorbent liquid. After solid-liquid separation, the liquid portion of the absorbent liquid is sent to a microbial oxidation tower containing a solution of *Thiobacillus ferrooxidans*, thus completing the desulfurization treatment of the fuel gas.

3. The efficient desulfurization process for fuel gas according to claim 2, characterized in that, The preparation of the hydrodesulfurization catalyst includes the following steps: (1) Prepare a mixed solution containing cobalt source and molybdenum source; (2) After grinding and sieving the alumina carrier, add it to the mixed solution obtained in step (1), mix evenly, and then perform ultrasonic impregnation treatment to obtain the impregnation solution. (3) The impregnation solution obtained in step (2) is dried and calcined to obtain catalyst powder; (4) The catalyst powder obtained in step (3) is mixed with binder and deionized water to prepare a slurry. The slurry is then shaped, dried and calcined to obtain the hydrodesulfurization catalyst.

4. The efficient desulfurization process for fuel gas according to claim 3, characterized in that, In step (1), the cobalt source is cobalt nitrate hexahydrate, the molybdenum source is ammonium molybdate tetrahydrate, and the atomic molar ratio of cobalt to molybdenum is 1:1 to 2.

5. The efficient desulfurization process for fuel gas according to claim 3, characterized in that, In step (2), the mass ratio of cobalt source to alumina is 1:1 to 2; the ultrasonic impregnation treatment time is 0.5 to 4 hours.

6. The efficient desulfurization process for fuel gas according to claim 3, characterized in that, In step (3), the calcination temperature is 480-520℃ and the calcination time is 2-12h.

7. The efficient desulfurization process for fuel gas according to claim 3, characterized in that, In step (4), the roasting temperature is 420-500℃ and the roasting time is 2-12h.

8. The efficient desulfurization process for fuel gas according to claim 2, characterized in that, The process conditions in the hydrodesulfurization tower are: reaction temperature 220–300℃, reaction pressure 0.1–0.5 MPa, and gas hourly space velocity 200–1000 h⁻¹. -1 .

9. The efficient desulfurization process for fuel gas according to claim 2, characterized in that, The absorbent was Fe2(SO4)3 absorbent with a concentration of 5–20 g / L.

10. The efficient desulfurization process for fuel gas according to claim 2, characterized in that, The process conditions for the absorption tower are: absorption temperature of 35–45℃, gas-liquid ratio of 5–15:1, and gas hourly space velocity of 200–1000 h⁻¹. -1 .

11. The efficient desulfurization process for fuel gas according to claim 2, characterized in that, The oxygen-to-sulfur ratio of the microbial oxidation tower is 1.2–1.8, and the reaction temperature is 25–35℃.

12. A system for implementing the efficient desulfurization process for fuel gas according to any one of claims 1 to 11, characterized in that, It includes a hydrodesulfurization tower, the bottom of which is connected to an absorption tower via a pipeline, the lower part of which is connected to a separator via a pipeline, and the separator is connected to a microbial oxidation tower via a pipeline.

13. The system according to claim 1, characterized in that, The upper part of the microbial oxidation tower is also connected to the tower side of the absorption tower via a pipe.

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