A desulfurization device

Abstract

The utility model discloses a desulfurization device, including PLC controller, raw material gas inlet, air import, monitor natural gas flow device, monitor air flow device, mixer, desulfurization system and filter monitoring device, desulfurization system is composed of first desulfurization tower and second desulfurization tower, and first desulfurization tower is divided into two layers of upper and lower and fills two kinds of desulfurizer respectively, and second desulfurization tower fills a kind of desulfurizer, and the product after the desulfurization of first desulfurization tower is adsorbed, is equipped with safety valve, pressure transmitter and hand valve respectively on two pipelines connected with venting mouth above two desulfurization towers, and filter monitoring device includes filter, oxygen content detection device and cut -off valve, the utility model discloses two desulfurization towers are carried out desulfurization technology, and make PLC controller can adjust the flow of raw material gas inlet or / and air import according to the received numerical value, and control the opening and closure of cut -off valve and safety valve, thereby, in the case where the safety of the product gas output is guaranteed, the desulfurization process reaction is also ensured to be sufficient.

Description

Technical Field

[0001] This utility model relates to the field of gas desulfurization technology, specifically a desulfurization device and method. Background Technology

[0002] The statements in this section are merely background information relating to this disclosure, and these statements may constitute prior art. In the process of developing this utility model, the inventors discovered at least the following problems in the prior art.

[0003] Natural gas, as a high-quality, efficient, and clean energy source, is not only widely used as an important chemical raw material in the production of methanol, ammonia, urea, and other high-value-added downstream products, but also as a significant energy source, widely applied in various sectors of national life and production. In recent years, in accordance with the requirements of the sustainable development strategy and national environmental protection policies, my country has been vigorously developing its natural gas industry, especially with the development and application of some new large-scale high-sulfur gas fields. Currently, the natural gas extracted in most regions exhibits a diverse composition, with most containing high levels of sulfides, such as inorganic sulfur like hydrogen sulfide (H2S) or organic sulfur like carbon disulfide (CS2). These sulfides cause significant atmospheric pollution during combustion. Therefore, appropriate desulfurization and purification treatment is essential during the extraction and application of natural gas.

[0004] Traditional natural gas purification technologies typically employ the amine method to remove CO2 and H2S from acidic natural gas. The commonly used amine solvents are primarily N-methyldiethanolamine (MDEA) and various formulations of MDEA. However, due to the chemical stability of CS2, the conventional amine method has a relatively low removal rate of organic sulfur in natural gas, resulting in low desulfurization precision. With the implementation of the new national standard for natural gas (GB17820-2018), the sulfur content requirements for product natural gas have been further tightened, stipulating that the total sulfur content of natural gas entering long-distance pipelines must be below 20 mg / Nm³. 3 Therefore, the inadequacy of traditional natural gas purification technologies is becoming increasingly apparent. Consequently, developing new and efficient natural gas desulfurization technologies has become a key research direction in this field.

[0005] For example, patent application number 202411910069.8, entitled "A Natural Gas Desulfurization Process," employs a liquid-phase oxidation-reduction method. It includes an absorption tower and a regeneration tower, both of which are bubbling towers. In the absorption tower, lean solution and sulfur-containing natural gas come into contact to generate rich solution and purified natural gas. The rich solution enters the regeneration tower and mixes with air for regeneration. The resulting lean solution overflows into a lean solution tank and is then pumped back into the absorption tower, thus achieving liquid circulation. However, this method may generate byproducts such as thiosulfates during desulfurization. For example, in vanadate / ADA desulfurization solutions, the reaction rate of H2S oxidation to elemental sulfur in the absorption tower is low, and a large number of HS- ions will be converted into polysulfides. These easily generate thiosulfate ions after entering the regenerator. When the solution pH exceeds 8.8, the amount of thiosulfate generated increases with increasing pH. Accumulation to a certain concentration will affect desulfurization efficiency and may require additional treatment. Furthermore, because it employs a mechanical flushing method using solution and airflow, corrosion issues can arise. Corrosion can occur in the ejector section above the liquid surface in the regeneration tank, inside the reaction tank and in dead zones of the liquid phase, in the lean solution pipelines, and in the regeneration and circulation tanks. Additionally, if an inappropriate desulfurization catalyst is selected, clogging problems may occur.

[0006] How to create a system and process with higher desulfurization efficiency and fewer defects is an urgent problem to be solved in this field. Summary of the Invention

[0007] In view of the above problems, the purpose of this utility model is to solve some of the problems in the prior art, or at least alleviate these problems.

[0008] A desulfurization device, comprising:

[0009] PLC controller;

[0010] The raw gas input system includes a raw gas inlet and a natural gas flow monitoring device; the natural gas flow monitoring device is used to detect the natural gas flow and transmit the numerical signal to the PLC controller.

[0011] An oxygen supplementation system includes an air inlet and an air flow monitoring device; the air flow monitoring device is used to detect the air flow and transmit the numerical signal to the PLC controller.

[0012] A mixer, the input of which is connected to the output of the raw gas input system and the oxygen supplementation system;

[0013] The desulfurization system includes a first desulfurization tower and a second desulfurization tower. The input end of the first desulfurization tower is connected to the output end of the mixer, and its output end is connected to the input end of the second desulfurization tower. The first desulfurization tower is divided into upper and lower layers, each filled with two different types of special desulfurizing agents to allow sulfur-containing natural gas to react with oxygen through the upper and lower layers, thereby achieving desulfurization. The second desulfurization tower is filled with a special desulfurizing agent to adsorb elemental sulfur and polysulfides after the reaction. Both the first and second desulfurization towers are equipped with automatic pressure relief devices connected to vent ports.

[0014] A filtration monitoring device is provided, with its input end connected to the output end of the second desulfurization tower and its output end connected to the product gas outlet. The filtration monitoring device includes a filter, an oxygen content detection device, and a shut-off valve. The oxygen content detection device is connected to the pipeline after the filter to measure the oxygen content of the product gas and transmit the signal to the PLC controller. The shut-off valve is located on the pipeline upstream of the product gas outlet.

[0015] The PLC controller is connected to the inlet valve of the raw gas inlet and / or air inlet, and is used to adjust the flow rate of the raw gas inlet and / or air inlet according to the values ​​of the natural gas flow monitoring device and the air flow monitoring device, as well as the value of the oxygen content detection device; the PLC controller is connected to the shut-off valve, and is used to control the opening and closing of the shut-off valve according to the value of the oxygen content detection device.

[0016] Furthermore, when the oxygen content detection device value is ≥0.8%, the PLC controller closes the shut-off valve; when the oxygen content detection device value is ≤0.2%, the PLC controller opens the shut-off valve.

[0017] Furthermore, the PLC controller calculates the numerical ratio based on the values ​​from the monitoring devices for natural gas flow and air flow, and adjusts the flow rates of the raw gas inlet and / or air inlet to make the numerical ratio conform to a pre-set specific numerical ratio.

[0018] Optionally, the device for monitoring natural gas flow is a gas turbine flow meter; the device for monitoring air flow is a metal rotor flow meter; preferably, the PLC controller is used to adjust the flow rate of the air inlet.

[0019] Furthermore, the upper layer of the first desulfurization tower is filled with a total of 4m³ of DK-102 special desulfurizing agent. 3 The lower layer is filled with a total of 6m³ of DK-104 desulfurizing agent. 3 The second desulfurization tower is filled with 12m³ of DK-104 desulfurizing agent. 3 .

[0020] The automatic pressure relief device includes a safety valve and a pressure transmitter; the pressure transmitter is used to detect the outlet pressure of the desulfurization tower and transmit the numerical signal to the PLC controller; the PLC controller is connected to the upstream regulating valve; the pipeline pressure of the air inlet is higher than the pipeline pressure of the desulfurization system.

[0021] The first and second desulfurization towers also include a manual valve, a drain valve, a desulfurizing agent loading port, and a desulfurizing agent unloading port; the manual valve is located on another pipeline connected to the vent port above the desulfurization tower and is used to release pressure when replacing the adsorbent; the drain valve is located below the desulfurization tower and is used to discharge the generated water from the desulfurization tower.

[0022] Preferably, the filter consists of two filters, one on and one on standby, which can be switched between each other.

[0023] This utility model has the following beneficial effects:

[0024] The purification process described in this application consists of a two-tower desulfurization process. The raw gas and air are mixed and then fed into the first and second desulfurization towers respectively. Desulfurization is carried out using desulfurizing agents packed within the towers. A safety valve is installed above each desulfurization tower to ensure the pressure inside the tower remains at a safe level. Simultaneously, a PLC controller monitors the flow rates of sulfur-containing natural gas and air, as well as the oxygen content of the product gas, using natural gas flow monitoring devices, air flow monitoring devices, and oxygen content detection devices. These values ​​are compared with preset values ​​to control the flow rates of the raw gas and / or air, and the opening and closing of the shut-off valves. This ensures that the product gas reaches the preset value before output, thus simultaneously achieving both sufficient desulfurization reaction and safety requirements, unaffected by pressure relief. Considering the different types of raw gas, the oxygen content of the raw gas and air can be initially determined using an oxygen content detection device, and this information can be input into the PLC controller for further coordination with the natural gas and air flow monitoring devices. Attached Figure Description

[0025] The above-described structure of this utility model can be further illustrated by the non-limiting embodiments given in the following drawings.

[0026] Figure 1 This is a process flow diagram of the present invention;

[0027] Figure 2 This is a perspective view of the present utility model;

[0028] Figure 3 This is a rear view of the present invention;

[0029] Figure 4 This is a partially enlarged view of the present invention.

[0030] Wherein: 1-Raw gas inlet; 2-Air inlet; 3-Natural gas flow monitoring device; 4-Air flow monitoring device; 5-PLC controller; 6-Mixer; 7-First desulfurization tower; 8-Second desulfurization tower; 9-Filter; 10-Product gas outlet; 11-Vent port; 12-Shut-off valve; 13-First safety valve; 14-Second safety valve; 15-First manual valve; 16-Second manual valve; 17-Oxygen content detection device; 18-Pressure transmitter. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings. The embodiments of the present invention are only used to illustrate the present invention and not to limit the present invention. Various substitutions and modifications made in accordance with ordinary technical knowledge and conventional means in the art without departing from the technical concept of the present invention should be included within the scope of the present invention.

[0032] To improve the efficiency and reduce defects of the desulfurization process, the applicant initially used two desulfurization towers to react sulfur-containing natural gas with oxygen for desulfurization. To ensure sufficient oxygen for reaction with the sulfur-containing natural gas and to reduce the oxygen content of the final product gas to below a specific value, thus preventing danger due to excessive oxygen content during use, a PLC controller 5 was used to control the mixing ratio of the raw gas and air within a reasonable range to achieve the above effects. However, further research revealed that the chemical reaction within the desulfurization towers caused pressure increases, which could be dangerous if the pressure exceeded a threshold. Therefore, installing an automatic pressure relief device at the desulfurization towers became essential. However, the applicant subsequently discovered that depressurizing the desulfurization towers affected the ratio of sulfur-containing natural gas to air, either leading to excess oxygen and excessively high oxygen content in the final product gas, posing a risk to its use, or insufficient oxygen to fully react with the sulfur-containing natural gas, reducing the desulfurization effect and affecting the quality of the product gas.

[0033] How to ensure the safe use of the product gas while guaranteeing the full progress of the desulfurization reaction, and without being affected by pressure relief, has been a key concern for the applicant. To address this, the following solution was designed.

[0034] like Figure 1 As shown in Figure 2, 3, or 4, a desulfurization device includes:

[0035] PLC controller 5;

[0036] The raw gas input system includes a raw gas inlet 1 and a natural gas flow monitoring device 3; the natural gas flow monitoring device 3 is used to detect the natural gas flow and transmit the numerical signal to the PLC controller 5.

[0037] The oxygen supplementation system includes an air inlet 2 and an air flow monitoring device 4; the air flow monitoring device 4 is used to detect the air flow and transmit the numerical signal to the PLC controller 5.

[0038] Mixer 6, the input end of which is connected to the output end of the raw material gas input system and the oxygen supplementation system;

[0039] The desulfurization system includes a first desulfurization tower 7 and a second desulfurization tower 8. The input end of the first desulfurization tower 7 is connected to the output end of the mixer 6, and its output end is connected to the input end of the second desulfurization tower 8. The first desulfurization tower 7 is divided into upper and lower layers, each filled with two different types of special desulfurizing agents to allow sulfur-containing natural gas to react with oxygen through the upper and lower layers, thereby achieving desulfurization. The second desulfurization tower 8 is filled with a special desulfurizing agent to adsorb elemental sulfur and polysulfides after the reaction. Both the first desulfurization tower 7 and the second desulfurization tower 8 are equipped with automatic pressure relief devices connected to vent outlet 11.

[0040] A filtration monitoring device is provided, with its input end connected to the output end of the second desulfurization tower 8 and its output end connected to the product gas outlet 10. The filtration monitoring device includes a filter 9, an oxygen content detection device 17, and a shut-off valve 12. The oxygen content detection device 17 is connected to the pipeline after the filter 9 to measure the oxygen content of the product gas and transmit the signal to the PLC controller 5. The shut-off valve 12 is located on the pipeline at the front end of the product gas outlet 10.

[0041] The PLC controller 5 is connected to the air inlet valve of the raw gas inlet 1 and / or air inlet 2, and is used to adjust the flow rate of the raw gas inlet 1 and / or air inlet 2 according to the values ​​of the natural gas flow monitoring device 3 and the air flow monitoring device 4, as well as the value of the oxygen content detection device 17; the PLC controller 5 is connected to the shut-off valve 12, and is used to control the opening and closing of the shut-off valve 12 according to the value of the oxygen content detection device 17.

[0042] The first desulfurization tower 7 in this application primarily allows high-concentration sulfur-containing natural gas to react with oxygen through two layers of desulfurizing agents. The desulfurizing agent in the second desulfurization tower 8 then adsorbs the reacted elemental sulfur and polysulfides, thus achieving desulfurization. To ensure a complete desulfurization reaction and the safety of the product gas, this application includes a natural gas flow monitoring device 3, an air flow monitoring device 4, and an oxygen content detection device 17. By detecting the flow rates of the sulfur-containing natural gas and air, as well as the oxygen content of the product gas, and comparing these values ​​with preset values, the flow rates of the raw material gas inlet 1 and / or air inlet 2 are adjusted. This, in conjunction with the shut-off valve 12, ensures that the product gas reaches the preset value before output, thereby simultaneously achieving the requirements of a complete desulfurization reaction and safety, unaffected by pressure relief.

[0043] In order to maintain the oxygen content of the product gas within a reasonable range before output, when the value of the oxygen content detection device 17 is ≥0.8%, the PLC controller 5 closes the shut-off valve 12 and adjusts the flow rate of the raw material gas inlet 1 and / or the air inlet 2 to reduce the oxygen content of the product gas; when the value of the oxygen content detection device 17 is ≤0.2%, the PLC controller 5 opens the shut-off valve 12, thereby outputting the product gas through the product gas outlet 10.

[0044] Furthermore, the PLC controller 5 calculates the numerical ratio based on the values ​​from the natural gas flow monitoring device 3 and the air flow monitoring device 4, and adjusts the flow rates of the raw gas inlet 1 and / or the air inlet 2 to make the numerical ratio conform to a pre-set specific numerical ratio, thereby ensuring the full progress of the desulfurization reaction.

[0045] The PLC control system has both automatic and manual modules, which can set the duration of sulfur-containing operation and the interval operation duration for each operating cycle, and can also be set according to the actual site conditions. To ensure desulfurization efficiency, this application preferably uses the PLC controller 5 to regulate the flow rate of air inlet 2, thereby eliminating the need to reduce the flow rate of sulfur-containing natural gas.

[0046] Oxygen supplementation system:

[0047] Since the desulfurization process is a catalytic oxidation process, oxygen is an essential reactant in this process, and the desulfurization products are elemental sulfur and high-boiling-point polysulfides. Therefore, the oxygen supplementation system operates by adding air, and thus the pipeline pressure of the air inlet 2 must be higher than the pipeline pressure of the desulfurization system.

[0048] The recommended oxygen supplementation amount is 2.25 Nm³. 3 / h, which translates to an air replenishment volume of 10.8 Nm. 3 / h (instrument air can be used, pressure 0.7MPa). The replenished air flow rate is interlocked with the feed gas flow rate to control the replenished air volume and adjust the oxygen concentration in the feed gas accordingly.

[0049] Note: The oxygen supplementation amount can be calculated at 2500ppm. The residual oxygen content after the reaction is about 1000ppm, which is far lower than the 0.5% oxygen content requirement in natural gas and complies with the natural gas pipeline operation specification SY / T 5922-2003.

[0050] The natural gas flow monitoring device 3 is a gas turbine flow meter with a flow detection range of 0.28-2.8m. 3 / h; the air flow monitoring device 4 is a metal rotor flow meter with a flow detection range of 13-250m³ / h. 3 / h. The signal current is 4-20mA.

[0051] The main function of mixer 6 is to fully mix sulfur-containing natural gas and air and then feed it into the first desulfurization tower 7.

[0052] Desulfurization system:

[0053] The purification process of this unit consists of a two-tower desulfurization process. The sulfur-containing regeneration gas from outside the boundary first enters the first desulfurization tower 7, then enters the second desulfurization tower 8. The gas exiting the desulfurization tower passes through the filter 9 and then enters the next process.

[0054] After air replenishment, the raw gas is processed using a two-tower series desulfurization process at ambient temperature, requiring no heating. The first desulfurization tower consists of two layers: the upper layer contains 4 m³ of DK-102 special desulfurizing agent, and the lower layer contains 6 m³ of DK-104 desulfurizing agent. The second desulfurization tower contains 12 m³ of DK-104 desulfurizing agent. The first desulfurization tower primarily reacts the high-concentration sulfur-containing natural gas with oxygen through both layers. The second desulfurization tower primarily adsorbs the elemental sulfur and polysulfides remaining after the reaction. After passing through both desulfurization towers, the purification requirements are met.

[0055] Reaction principle:

[0056] DK-102 Special Desulfurizer:

[0057] CS2 is deeply removed through adsorption, absorption, and catalytic oxidation reactions; H2S can be removed simultaneously in an integrated manner.

[0058] 2CS2+O2→2CO2+4S, 2H2S+O2→2H2O+2S

[0059] DK-104 mercaptan-specific desulfurizer:

[0060] It is made by adding certain active components and special accelerators to high-quality activated carbon, followed by calcination, impregnation, and drying. It can be used alone for the catalytic oxidation removal of mercaptan, or for the integrated removal of mercaptan and hydrogen sulfide, and features a short process, high sulfur capacity, and low desulfurization cost.

[0061] 2H2S+O2→2H2O+2S, 4R-SH+O2→2R-SS-R+2H2O

[0062] The aforementioned DK-102 special desulfurizer and DK-104 mercaptan-specific desulfurizer are both existing products. They can be used to remove sulfides such as carbon disulfide, hydrogen sulfide, and mercaptan from raw gas, so that the sulfides in the gas are removed at room temperature and meet the purification index requirements.

[0063] Specialized desulfurizing agents have a limited capacity; once saturated, they cannot be regenerated and must be replaced with new ones. Therefore... Figure 1As shown, the first desulfurization tower 7 and the second desulfurization tower 8 also include a manual valve, a drain valve, a desulfurizing agent loading port, and a desulfurizing agent unloading port; the manual valve is located on another pipeline connected to the vent 11 above the desulfurization tower, used for pressure relief when replacing the adsorbent; the drain valve is located below the desulfurization tower, used to discharge the generated water from the desulfurization tower. Figure 1 As shown, a first manual valve 15 is installed on a branch pipe connected to the vent 11 above the first desulfurization tower 7, and a second manual valve 16 is installed on a branch pipe connected to the vent 11 above the second desulfurization tower 8. When it is necessary to replace the desulfurizing agent, the above manual valves can be operated to manually release the pressure before replacing the desulfurizing agent.

[0064] To ensure pressure release, the automatic pressure release device includes a safety valve and a pressure transmitter 18. The pressure transmitter 18 detects the outlet pressure of the desulfurization tower and transmits the numerical signal to the PLC controller 5. Pressure detection range: 0-2.5 MPa, relative humidity: 0-85%. When the pressure exceeds a specific value, the safety valve can automatically open, or the PLC controller 5 can partially close the upstream regulating valve to release the gas. Figure 1 As shown, a first safety valve 13 is installed on the pipe connected to the vent 11 above the first desulfurization tower 7, and a second safety valve 14 is installed on the pipe connected to the vent 11 above the second desulfurization tower 8. Both are connected to the PLC controller 5 to achieve automatic pressure relief.

[0065] Filter 9 is mainly used to filter impurities in the product gas. There can be two filters, one in operation and one on standby, which can be switched between each other.

[0066] The process flow includes the following steps:

[0067] Simultaneously, raw gas (i.e., sulfur-containing natural gas) and air are introduced from raw gas inlet 1 and air inlet 2, respectively;

[0068] The natural gas flow rate is detected by the natural gas flow monitoring device 3 (i.e., gas turbine flow meter) and the air flow rate monitoring device 4 (i.e., metal rotor flow meter), and the numerical signals are transmitted to the PLC controller 5.

[0069] The PLC controller 5 calculates the numerical ratio based on the values ​​from the natural gas flow monitoring device 3 and the air flow monitoring device 4, and controls the air inlet valves of the raw gas inlet 1 and / or the air inlet 2 to control the flow rate of the raw gas and / or the air, so that the numerical ratio conforms to a pre-set specific numerical ratio.

[0070] The raw gas and air, meeting a pre-set specific ratio, are thoroughly mixed at mixer 6 and then fed into the first desulfurization tower 7. The sulfur-containing natural gas reacts with oxygen through two layers of DK-102 and DK-104 special desulfurizing agents. The chemical reaction formula of the DK-102 special desulfurizing agent is as follows:

[0071] 2CS2+O2→2CO2+4S, 2H2S+O2→2H2O+2S

[0072] The chemical reaction formula for DK-104 desulfurizer is as follows:

[0073] 2H2S+O2→2H2O+2S, 4R-SH+O2→2R-SS-R+2H2O

[0074] The reacted gas is fed into the second desulfurization tower 8, where the elemental sulfur and polysulfides are adsorbed by the DK-104 desulfurizing agent.

[0075] Meanwhile, pressure transmitter 18 detects the pressure of the first desulfurization tower 7 and the second desulfurization tower 8; when the pressure inside the desulfurization tower exceeds a specific value, the regulating valve of the upstream section is closed or the safety valve is opened to automatically discharge the gas.

[0076] The gas, after adsorbing elemental sulfur and polysulfides, is filtered through filter 9 to remove impurities. Then, the oxygen content of the product gas is detected by oxygen content detection device 17, and the numerical signal is transmitted to PLC controller 5. When the oxygen content of the product gas is ≥0.8%, PLC controller 5 closes shut-off valve 12 and adjusts the flow rate of the raw material gas inlet 1 and / or air inlet 2. When the oxygen content of the product gas drops to ≤0.2%, PLC controller 5 opens shut-off valve 12 and outputs the product gas through product gas outlet 10. When the oxygen content of the product gas is <0.2%, PLC controller 5 adjusts the flow rate of the raw material gas inlet 1 and / or air inlet 2 to maintain the oxygen content of the product gas between 0.2% and 0.8%.

[0077] The desulfurization method also includes replacing the desulfurizing agent; when the desulfurizing agent needs to be replaced or the desulfurizing agent fails, the raw material gas inlet 1 and the air inlet 2 are closed, and the manual valve on another pipeline connected to the vent 11 above the first desulfurization tower 7 or the second desulfurization tower is opened to release the gas and relieve pressure. Then the desulfurizing agent is replaced through the desulfurizing agent loading port and desulfurizing agent unloading port set on the desulfurization tower.

[0078] Since the pressure resistance of desulfurization towers and the sulfur content of raw gas vary, the specific pressure value and the specific mixing value need to be determined by testing based on the actual situation. For example, the specific mixing value or range for the safe oxygen content of the product gas can also be determined by using the oxygen content detection device 17 to measure the oxygen content.

[0079] This application ensures the safety of the output product gas while guaranteeing a complete desulfurization process, significantly improving desulfurization efficiency. Furthermore, it eliminates defects such as clogging and corrosion, demonstrating significant market potential. Unless otherwise specified, fixed connections can include riveting, welding, bolting, etc., while movable connections can include hinged connections, etc.

Claims

1. A desulfurization device, characterized in that, include: PLC controller (5); The raw gas input system includes a raw gas inlet (1) and a natural gas flow monitoring device (3); the natural gas flow monitoring device (3) is used to detect the natural gas flow and transmit the numerical signal to the PLC controller (5); The oxygen supplementation system includes an air inlet (2) and an air flow monitoring device (4); the air flow monitoring device (4) is used to detect the air flow and transmit the numerical signal to the PLC controller (5); The mixer (6) has its input end connected to the output end of the raw material gas input system and the oxygen supplementation system; The desulfurization system includes a first desulfurization tower (7) and a second desulfurization tower (8); the input end of the first desulfurization tower (7) is connected to the output end of the mixer (6), and its output end is connected to the input end of the second desulfurization tower (8); the first desulfurization tower (7) is divided into upper and lower layers, which are respectively filled with two different types of special desulfurizing agents, so that the sulfur-containing natural gas can react with oxygen through the upper and lower layers to achieve desulfurization; the second desulfurization tower (8) is filled with a special desulfurizing agent, which is used to adsorb elemental sulfur and polysulfides after the reaction; both the first desulfurization tower (7) and the second desulfurization tower (8) are equipped with automatic pressure discharge devices, which are connected to the vent (11); A filter monitoring device is provided, with its input end connected to the output end of the second desulfurization tower (8) and its output end connected to the product gas outlet (10). The filter monitoring device includes a filter (9), an oxygen content detection device (17), and a shut-off valve (12). The oxygen content detection device (17) is connected to the pipeline after the filter (9) to measure the oxygen content of the product gas and transmit the signal to the PLC controller (5). The shut-off valve (12) is located on the pipeline at the front end of the product gas outlet (10). The PLC controller (5) is connected to the air inlet valve of the raw gas inlet (1) and / or air inlet (2) to adjust the flow rate of the raw gas inlet (1) and / or air inlet (2) according to the values ​​of the natural gas flow monitoring device (3) and the air flow monitoring device (4) and the oxygen content detection device (17); the PLC controller (5) is connected to the shut-off valve (12) to control the opening and closing of the shut-off valve (12) according to the value of the oxygen content detection device (17).

2. The desulfurization device according to claim 1, characterized in that, When the value of the oxygen content detection device (17) is ≥0.8%, the PLC controller (5) closes the shut-off valve (12); when the value of the oxygen content detection device (17) is ≤0.2%, the PLC controller (5) opens the shut-off valve (12).

3. The desulfurization device according to claim 1 or 2, characterized in that, The PLC controller (5) calculates the numerical ratio based on the values ​​of the natural gas flow monitoring device (3) and the air flow monitoring device (4), and adjusts the flow rate of the raw gas inlet (1) and / or the air inlet (2) so that the numerical ratio conforms to a pre-set specific numerical ratio.

4. The desulfurization device according to claim 3, characterized in that, The natural gas flow monitoring device (3) is a gas turbine flow meter; the air flow monitoring device (4) is a metal rotor flow meter; and the PLC controller (5) is used to adjust the flow rate of the air inlet (2).

5. The desulfurization device according to claim 1, characterized in that, The upper layer of the first desulfurization tower (7) is filled with a total of 4m³ of DK-102 special desulfurizing agent. 3 The lower layer is filled with a total of 6m³ of DK-104 desulfurizing agent. 3 The second desulfurization tower (8) is filled with 12m³ of DK-104 desulfurizing agent. 3 .

6. The desulfurization device according to claim 1, characterized in that, The automatic pressure relief device includes a safety valve and a pressure transmitter (18); the pressure transmitter (18) is used to detect the outlet pressure of the desulfurization tower and transmit the numerical signal to the PLC controller (5); the PLC controller is connected to the regulating valve of the upstream section; the pipeline pressure of the air inlet (2) is higher than the pipeline pressure of the desulfurization system.

7. The desulfurization device according to claim 1, characterized in that, The first desulfurization tower (7) and the second desulfurization tower (8) also include a manual valve, a drain valve, a desulfurizing agent loading port and a desulfurizing agent unloading port; the manual valve is located on another pipeline connected to the vent (11) above the desulfurization tower and is used to release pressure when replacing the adsorbent; the drain valve is located below the desulfurization tower and is used to discharge the generated water from the desulfurization tower.

8. The desulfurization device according to claim 1, characterized in that, The filter (9) consists of two filters, one on and one on standby, which can be switched between each other.

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