A sulfur recovery pretreatment system

Abstract

The utility model relates to the technical field of coal gasification, specifically relates to a kind of sulfur recovery pretreatment system, the system includes acid gas absorption tower, for the poor liquid into tower and sulfur-rich acid gas countercurrent contact, absorb H2S in sulfur-rich acid gas and get rich liquid;Lean rich liquid heat exchanger before flashing, for the rich liquid from the lower part of acid gas absorption tower is carried out heat exchange;Rich liquid flash tank, for the rich liquid after heat exchange after lean rich liquid heat exchanger before flashing is carried out flashing;Lean rich liquid heat exchanger after flashing, for the rich liquid from rich liquid flash tank is carried out heat exchange;Solvent regeneration tower, for the rich liquid after heat exchange after lean rich liquid heat exchanger after flashing is regenerated into poor liquid, and the poor liquid after regeneration is sequentially transported to poor liquid storage tank by lean rich liquid heat exchanger after flashing and lean rich liquid heat exchanger before flashing, and H2S gas desorbed from rich liquid is transported to sulfur recovery equipment. Using the system, H2S gas in sulfur-rich acid gas can be effectively recovered for sulfur.

Description

Technical Field

[0001] This utility model relates to the field of coal gasification technology, specifically to a sulfur recovery pretreatment system. Background Technology

[0002] In coal gasification processes, in order to recover and utilize sulfur resources, it is usually necessary to recover H2S from sulfur-rich gas from the low-temperature methanol washing section for sulfur production. However, existing sulfur recovery pretreatment equipment for sulfur-rich gas generally suffers from low recovery efficiency, poor recovery effect, and high recovery cost, making it difficult to effectively utilize sulfur resources and hindering the development of sulfur resource application.

[0003] Therefore, there is an urgent need for a sulfur recovery pretreatment system to effectively improve the efficiency and effectiveness of sulfur resource utilization and reduce recovery costs. Utility Model Content

[0004] The purpose of this invention is to address the problems of low recovery efficiency, poor recovery effect, and high recovery cost in existing sulfur recovery pretreatment equipment for sulfur-rich gases. This invention provides a sulfur recovery pretreatment system to effectively improve the efficiency and effectiveness of sulfur resource utilization and reduce recovery costs.

[0005] To achieve the above objectives, this utility model provides a sulfur recovery pretreatment system, the sulfur recovery pretreatment system comprising:

[0006] An acid gas absorption tower has a lean liquid inlet at the top and an acid gas inlet at the bottom, which is used to make the lean liquid entering the tower come into countercurrent contact with the sulfuric acid-rich gas, absorb H2S in the sulfuric acid-rich gas and obtain a rich liquid.

[0007] A lean solution storage tank is used to supply lean solution to the acid gas absorption tower;

[0008] A pre-flash heat exchanger for rich and lean liquor is used to exchange heat with the rich liquor from the lower part of the acid gas absorption tower.

[0009] A rich liquid flash evaporator is used to flash evaporate a rich liquid that has been heat-exchanged by the pre-flash evaporator lean-rich liquid heat exchanger.

[0010] A heat exchanger for rich and lean liquids after flash evaporation is used to exchange heat with the rich liquid from the rich liquid flash tank.

[0011] The solvent regeneration tower is used to regenerate the rich liquid after heat exchange in the flash-exchange-lean-rich-liquid heat exchanger into a lean liquid, and to transport the regenerated lean liquid sequentially through the flash-exchange-lean-rich-liquid heat exchanger and the flash-exchange-lean-rich-liquid heat exchanger to the lean liquid storage tank, and to transport the H2S gas desorbed from the rich liquid to the sulfur recovery equipment.

[0012] Preferably, the solvent regeneration tower includes a kettle reboiler with low-pressure steam as a heat source, the kettle reboiler being used to exchange heat with the liquid phase inside the solvent regeneration tower.

[0013] Preferably, the lean liquid storage tank is maintained at a slightly positive pressure by means of a water seal and protective gas pressure replenishment.

[0014] Preferably, a first cooling device is provided between the pre-flash heat exchanger for lean and rich liquor and the lean liquor storage tank, for cooling the lean liquor to a set temperature before conveying it to the lean liquor storage tank.

[0015] Preferably, the first cooling device includes a lean liquid air cooler and a lean liquid aftercooler connected in sequence along the lean liquid conveying direction.

[0016] Preferably, a lean liquid filter is provided between the lean liquid storage tank and the acid gas absorption tower to filter out impurities in the lean liquid;

[0017] A rich liquid filter is provided between the acid gas absorption tower and the pre-flash evaporation lean and rich liquid heat exchanger to filter out impurities in the rich liquid.

[0018] Preferably, it further includes:

[0019] The second cooling device is used to cool the H2S gas desorbed from the solvent regeneration tower;

[0020] A cooling reflux tank is used to reflux the liquid phase of the H2S gas cooled by the second cooling equipment back to the solvent regeneration tower, and the gas phase is transported to the sulfur recovery equipment and / or the acid gas absorption tower.

[0021] Preferably, the second cooling device includes a regeneration tower air cooler and a regeneration tower aftercooler connected in sequence along the conveying direction of the desorbed H2S gas.

[0022] Preferably, it also includes an acid gas separator for separating the sulfuric acid-rich gas into a liquid phase and then transporting it to an acid gas absorption tower.

[0023] Preferably, it also includes a fuel gas separator for separating the gas output from the acid gas absorption tower.

[0024] Compared with the prior art, this utility model has the following advantages:

[0025] 1. By setting up an acidic gas absorption tower, a pre-flash heat exchanger for lean and rich liquids, a rich liquid flash tank, a post-flash heat exchanger for lean and rich liquids, and a solvent regeneration tower for synergistic effect, H2S in sulfur-rich gas can be recovered sustainably and efficiently to realize the utilization of sulfur resources and reduce the energy consumption for regeneration of lean liquids.

[0026] 2. By setting the solvent regeneration tower to include a kettle reboiler with low-pressure steam as the heat source, compared with conventional thermosiphon reboilers, the equipment has less corrosion and a longer service life, which can effectively avoid the reduction in the efficiency of sulfur resource recovery and utilization caused by equipment failure.

[0027] 3. By setting the lean liquor storage tank to use a water seal and a protective gas pressure replenishment method to maintain a slight positive pressure, the oxidation and deterioration of the lean liquor solvent in the lean liquor storage tank can be effectively prevented, thus affecting the recovery effect. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the sulfur recovery pretreatment system.

[0029] Explanation of reference numerals in the attached figures

[0030] 1. Acid gas separator; 2. Acid gas absorption tower; 3. Fuel gas separator; 4. Lean liquid storage tank; 5. Lean liquid filter; 6. Lean liquid aftercooler; 7. Lean liquid air cooler; 8. Rich liquid filter; 9. Pre-flash heat exchanger for lean and rich liquids; 10. Rich liquid flash tank; 11. Post-flash heat exchanger for lean and rich liquids; 12. Solvent regeneration tower; 13. Kettle reboiler; 14. Regeneration tower air cooler; 15. Regeneration tower aftercooler; 16. Cooling reflux tank. Detailed Implementation

[0031] The following provides a detailed description of the specific embodiments of this utility model. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this utility model.

[0032] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or implying the number of technical features indicated. Therefore, unless otherwise stated, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. The term "comprising" and any variations thereof mean a non-exclusive inclusion, the possibility of the presence or addition of one or more other features, units, components, and / or combinations thereof.

[0033] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] This utility model provides a sulfur recovery pretreatment system, such as Figure 1As shown, the sulfur recovery pretreatment system includes:

[0035] Acid gas absorption tower 2 has a lean liquid inlet at the upper part of the tower body and an acid gas inlet at the lower part, which is used to make the lean liquid entering the tower come into countercurrent contact with the sulfuric acid-rich gas, absorb H2S in the sulfuric acid-rich gas and obtain rich liquid.

[0036] Lean liquor storage tank 4 is used to supply lean liquor to the acid gas absorption tower 2;

[0037] The pre-flash heat exchanger 9 is used to exchange heat with the rich liquid from the lower part of the acid gas absorption tower 2.

[0038] The rich liquid flash evaporator 10 is used to flash the rich liquid after it has been heated by the pre-flash evaporation lean rich liquid heat exchanger 9; wherein the light hydrocarbon components flashed out are recovered and reused.

[0039] The rich and lean liquid heat exchanger 11 after flash evaporation is used to exchange heat with the rich liquid from the rich liquid flash tank 10;

[0040] Solvent regeneration tower 12 is used to regenerate the rich liquid after heat exchange in the flash-exchange-lean-rich-liquid heat exchanger 11 into lean liquid, and to transport the regenerated lean liquid sequentially through the flash-exchange-lean-rich-liquid heat exchanger 11 and the flash-exchange-lean-rich-liquid heat exchanger 9 to the lean liquid storage tank 4, and to transport the H2S gas desorbed from the rich liquid to the sulfur recovery equipment.

[0041] According to the above technical solution, based on this sulfur recovery pretreatment system, in practical applications, H2S in sulfur-rich gas can be recovered sustainably and efficiently to realize the utilization of sulfur resources and reduce the regeneration energy consumption of lean liquid.

[0042] In the sulfur recovery pretreatment system of this utility model, preferably, the solvent regeneration tower 12 includes a kettle reboiler 13 with low-pressure steam as a heat source. The kettle reboiler 13 is used for heat exchange of the liquid phase inside the solvent regeneration tower 12. Specifically, compared with conventional thermosiphon reboilers, the kettle reboiler 13 has less equipment corrosion, a longer service life, and can effectively avoid the reduction in the efficiency of sulfur resource recovery and utilization caused by equipment failure.

[0043] In the sulfur recovery pretreatment system described in this utility model, preferably, the lean liquor storage tank 4 is maintained at a slightly positive pressure using a water seal and a protective gas pressurization method, which can effectively prevent the lean liquor solvent in the storage tank from oxidizing and deteriorating, thus affecting the recovery effect. Specifically, the protective gas is nitrogen.

[0044] In the sulfur recovery pretreatment system of this utility model, preferably, a lean liquid filter 5 is provided between the lean liquid storage tank 4 and the acid gas absorption tower 2 to filter out impurities in the lean liquid, thereby preventing impurities in the lean liquid from clogging the acid gas absorption tower 2 and affecting the absorption efficiency.

[0045] In another preferred embodiment, a rich liquid filter 8 is provided between the acid gas absorption tower 2 and the pre-flash evaporation lean and rich liquid heat exchanger 9 to filter out impurities in the rich liquid, thereby avoiding clogging of downstream equipment and affecting the overall absorption efficiency.

[0046] In the sulfur recovery pretreatment system of this utility model, preferably, a first cooling device is provided between the pre-flash evaporation lean and rich liquor heat exchanger 9 and the lean liquor storage tank 4, which is used to cool the lean liquor to a set temperature and then transport it to the lean liquor storage tank 4, thereby effectively avoiding the effect of excessively high temperature of the regenerated lean liquor on the absorption of H2S.

[0047] Specifically, the first cooling device includes a lean liquid air cooler 7 and a lean liquid aftercooler 6 connected sequentially along the lean liquid conveying direction, thereby better cooling the lean liquid. More specifically, the temperature of the lean liquid after being cooled by the lean liquid air cooler 7 is 50-55℃, and the temperature of the lean liquid after being cooled by the lean liquid aftercooler 6 is 35-45℃.

[0048] Preferably, the sulfur recovery pretreatment system of this utility model further includes:

[0049] The second cooling device is used to cool the H2S gas desorbed from the solvent regeneration tower 12;

[0050] Cooling reflux tank 16 is used to reflux the liquid phase of H2S gas cooled by the second cooling equipment to the solvent regeneration tower 12, and the gas phase is transported to the sulfur recovery equipment and / or the acid gas absorption tower 2.

[0051] In this embodiment of the invention, by using the cooling reflux tank 16 to further recycle a portion of the desorbed H2S gas back to the acid gas absorption tower 2 as needed, the concentration of H2S in the sulfur-rich gas at the inlet of the acid gas absorption tower 2 can be effectively increased, thereby improving the recovery effect of H2S in the sulfur-rich gas. Furthermore, by using the cooling reflux tank 16 to recycle the liquid phase of the H2S gas cooled by the second cooling device back to the solvent regeneration tower 12, the loss of lean solution can be reduced, thus lowering the cost of using lean solution.

[0052] In one specific embodiment, the second cooling device includes a regeneration tower air cooler 14 and a regeneration tower aftercooler 15 connected sequentially along the conveying direction of the desorbed H2S gas, thereby effectively improving the cooling effect. Specifically, the temperature of the H2S gas cooled by the regeneration tower air cooler 14 is 50-55°C, and the temperature of the H2S gas cooled by the regeneration tower aftercooler 15 is 35-45°C.

[0053] In the sulfur recovery pretreatment system described in this utility model, preferably, it also includes an acid gas separator 1, which is used to separate the sulfur-rich gas into a liquid phase and transport it to the acid gas absorption tower 2, so as to better absorb H2S in the sulfur-rich gas and discharge the separated liquid phase water.

[0054] In the sulfur recovery pretreatment system described in this utility model, preferably, a fuel gas separator 3 is also included, used to separate the gas output from the acidic gas absorption tower 2, thereby better utilizing the fuel components in the sulfuric acid-rich gas after H2S removal. Specifically, after separation, the gas phase is sent to the power station, and the liquid phase is directly discharged.

[0055] In this invention, the reaction between H2S in sulfuric acid-rich gas and amine-poor solution is completed almost instantaneously, and its main chemical reaction formula is as follows:

[0056] In this invention, the acid gas absorption tower 2 is one of the key pieces of equipment in the system. Sulfuric acid-rich gas enters the lower part of the absorption tower and comes into countercurrent contact with the lean liquid entering from the upper part. The lean liquid absorbs the H2S from the acid gas to obtain a rich liquid. Specifically, the acid gas absorption tower is a plate tower with a diameter of DN2200mm, a design pressure of 0.4MPa, and a design temperature of 80℃. The main material (plate) is corrosion-resistant steel S32168. Preferably, it is connected to the fuel gas separator 3 via a skirt support, and the total height of the two pieces of equipment is approximately 31.5m.

[0057] Solvent regeneration tower 12 is another key piece of equipment in this system. Specifically, this tower has 25 trays, with trays 1-2 being single overflow trays and trays 3-25 being double overflow trays. More specifically, the solvent regeneration tower has a diameter of DN2600mm, a total height of approximately 35.5m, a design pressure of 0.42MPa, a design temperature of 145℃, and its main material (plate) is corrosion-resistant steel S32168.

[0058] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto.

[0059] Example 1

[0060] Adopting such Figure 1 The sulfur recovery pretreatment system shown recovers H2S from sulfur-rich gas for sulfur production. Specifically, the sulfur recovery pretreatment system includes:

[0061] Acid gas absorption tower 2 has a lean liquid inlet at the upper part of the tower body and an acid gas inlet at the lower part, which is used to make the lean liquid entering the tower come into countercurrent contact with the sulfuric acid-rich gas, absorb H2S in the sulfuric acid-rich gas and obtain rich liquid.

[0062] Lean liquor storage tank 4 is used to supply lean liquor to the acid gas absorption tower 2;

[0063] The pre-flash heat exchanger 9 is used to exchange heat with the rich liquid from the lower part of the acid gas absorption tower 2.

[0064] The rich liquid flash evaporator 10 is used to flash the rich liquid after it has been heated by the pre-flash rich liquid heat exchanger 9.

[0065] The rich and lean liquid heat exchanger 11 after flash evaporation is used to exchange heat with the rich liquid from the rich liquid flash tank 10;

[0066] Solvent regeneration tower 12 is used to regenerate the rich liquid after heat exchange in the flash-exchange-lean-rich liquid heat exchanger 11 into lean liquid, and to transport the regenerated lean liquid sequentially through the flash-exchange-lean-rich liquid heat exchanger 11 and the flash-exchange-lean-rich liquid heat exchanger 9 to the lean liquid storage tank 4, and to transport the H2S gas desorbed from the rich liquid to the sulfur recovery equipment.

[0067] Specifically, it also includes a fuel gas separator 3 for separating the gas output from the acid gas absorption tower 2; it also includes an acid gas separator 1 for separating the sulfuric acid-rich gas into a liquid phase and then conveying it to the acid gas absorption tower 2; a first cooling device is provided between the pre-flash evaporation lean-rich liquid heat exchanger 9 and the lean liquid storage tank 4 for cooling the lean liquid to a set temperature before conveying it to the lean liquid storage tank 4; the first cooling device includes a lean liquid air cooler 7 and a lean liquid aftercooler 6 connected sequentially along the lean liquid conveying direction; a lean liquid filter 5 is provided between the lean liquid storage tank 4 and the acid gas absorption tower 2 for filtering out impurities in the lean liquid; a rich liquid filter 8 is provided between the acid gas absorption tower 2 and the pre-flash evaporation lean-rich liquid heat exchanger 9 for filtering out impurities in the rich liquid.

[0068] In practical applications, 22°C sulfuric acid-rich gas from the upstream low-temperature methanol washing section is separated into liquid water by the acidic gas separator 1 and then enters from the bottom of the acidic gas absorption tower 2. Simultaneously, 40°C amine lean liquid stored in the lean liquid storage tank 4, after impurity removal, enters from the top of the acidic gas absorption tower 2 and comes into countercurrent contact with the sulfuric acid-rich gas entering from the bottom. The rich liquid, having absorbed H2S from the sulfuric acid-rich gas, is heated to 55°C and discharged from the bottom of the acidic gas absorption tower 2. After impurity removal, it is then transported to the pre-flash heat exchanger 9 for heat exchange. The rich liquid, heated to 65°C, is then transported to the rich liquid flash tank 10 for flash evaporation. Finally, the flash-evaporated rich liquid is transported to the post-flash heat exchanger 11 for further heat exchange. The rich liquid, heated to 95°C, is then transported to solvent regeneration tower 12 for regeneration. Finally, the regenerated lean liquid at 123°C is sequentially transported to lean liquid storage tank 4 for recycling via flash-evaporated lean-rich liquid heat exchanger 11, pre-flash-evaporated lean-rich liquid heat exchanger 9, lean liquid air cooler 7, and lean liquid aftercooler 6. The H2S gas desorbed from the rich liquid is transported to sulfur recovery equipment for sulfur production. Specifically, after the regenerated 123°C lean liquid exchanges heat with the rich liquid in flash-evaporated lean-rich liquid heat exchanger 11, the temperature drops to 114°C. After exchanging heat with the rich liquid in pre-flash-evaporated lean-rich liquid heat exchanger 9, the temperature drops to 85°C. After being cooled by lean liquid air cooler 7, the temperature drops to 55°C. After being cooled by lean liquid aftercooler 6, the temperature drops to 40°C.

[0069] Testing has shown that the sulfur recovery pretreatment system described in this invention, compared with existing technical solutions, can sustainably and efficiently recover H2S from sulfur-rich gas to achieve sulfur resource utilization and reduce the regeneration energy consumption of lean liquid.

[0070] Example 2

[0071] The solvent regeneration tower 12 is implemented in accordance with Example 1, except that the solvent regeneration tower 12 includes a kettle reboiler 13 with low-pressure steam as a heat source, which is used to exchange heat with the liquid phase inside the solvent regeneration tower 12.

[0072] Testing revealed that the sulfur recovery pretreatment system described in this invention, compared to the scheme in Example 1 and the conventional thermosiphon reboiler, exhibits less equipment corrosion, a longer service life, and effectively avoids reduced efficiency in sulfur resource recovery and utilization due to equipment failure.

[0073] Example 3

[0074] The implementation follows the same procedure as Example 2, except that the lean liquid storage tank 4 is maintained at a slightly positive pressure by using a water seal and nitrogen pressurization.

[0075] Testing revealed that the sulfur recovery pretreatment system described in this invention, compared to the scheme in Example 2, can effectively prevent the lean liquor solvent in the lean liquor storage tank from oxidizing and deteriorating, thus affecting the recovery effect.

[0076] Example 4

[0077] The implementation refers to Example 3, but differs from it in that it also includes:

[0078] The second cooling device is used to cool the H2S gas desorbed from the solvent regeneration tower 12;

[0079] Cooling reflux tank 16 is used to reflux the liquid phase of H2S gas cooled by the second cooling device back to the solvent regeneration tower 12, and the gas phase is transported to the sulfur recovery device and / or the acid gas absorption tower 2; the second cooling device includes a regeneration tower air cooler 14 and a regeneration tower aftercooler 15 connected in sequence along the transport direction of the desorbed H2S gas.

[0080] Testing revealed that, compared to the scheme in Example 3, the sulfur recovery pretreatment system described in this utility model can further reduce the loss of lean liquid, lower the cost of using lean liquid, and improve the recovery effect of H2S in sulfur-rich gas by increasing the H2S concentration in the sulfur-rich gas at the inlet of the acid gas absorption tower.

[0081] The sulfur recovery pretreatment system provided by this utility model achieves sustainable and efficient recovery of H2S from sulfur-rich gas by synergistically setting up an acidic gas absorption tower, a pre-flash heat exchanger for lean and rich liquids, a rich liquid flash tank, a post-flash heat exchanger for lean and rich liquids, and a solvent regeneration tower, thereby realizing the utilization of sulfur resources and reducing the energy consumption for the regeneration of lean liquids.

[0082] The preferred embodiments of this utility model have been described in detail above; however, this utility model is not limited thereto. Within the scope of the technical concept of this utility model, various simple modifications can be made to the technical solution of this utility model. To avoid unnecessary repetition, this utility model will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed by this utility model and all fall within the protection scope of this utility model.

Claims

1. A sulfur recovery pretreatment system, characterized in that, The sulfur recovery pretreatment system includes: Acid gas absorption tower (2) has a lean liquid inlet at the upper part and an acid gas inlet at the lower part of the tower body, which is used to make the lean liquid entering the tower come into countercurrent contact with the sulfuric acid gas, absorb H2S in the sulfuric acid gas and obtain a rich liquid. A lean liquid storage tank (4) is used to supply lean liquid to the acid gas absorption tower (2); A pre-flash heat exchanger (9) is used to exchange heat with the rich liquid from the lower part of the acid gas absorption tower (2); A rich liquid flash tank (10) is used to flash the rich liquid after it has been heated by the pre-flash rich liquid heat exchanger (9); A rich-lean liquid heat exchanger (11) is used to exchange heat with the rich liquid from the rich liquid flash tank (10); The solvent regeneration tower (12) is used to regenerate the rich liquid after heat exchange in the flash-exchange-lean-rich liquid heat exchanger (11) into a lean liquid, and to transport the regenerated lean liquid sequentially through the flash-exchange-lean-rich liquid heat exchanger (11) and the flash-exchange-lean-rich liquid heat exchanger (9) to the lean liquid storage tank (4), and to transport the H2S gas desorbed from the rich liquid to the sulfur recovery equipment.

2. The sulfur recovery pretreatment system according to claim 1, characterized in that, The solvent regeneration tower (12) includes a kettle reboiler (13) with low-pressure steam as a heat source, which is used to exchange heat with the liquid phase inside the solvent regeneration tower (12).

3. The sulfur recovery pretreatment system according to claim 1, characterized in that, The lean liquid storage tank (4) is maintained at a slightly positive pressure by means of water seal and protective gas pressure replenishment.

4. The sulfur recovery pretreatment system according to any one of claims 1-3, characterized in that, A first cooling device is provided between the pre-flash heat exchanger (9) and the lean liquid storage tank (4) to cool the lean liquid to a set temperature before transporting it to the lean liquid storage tank (4).

5. The sulfur recovery pretreatment system according to claim 4, characterized in that, The first cooling device includes a lean liquid air cooler (7) and a lean liquid aftercooler (6) connected in sequence along the lean liquid conveying direction.

6. The sulfur recovery pretreatment system according to claim 1, characterized in that, A lean liquid filter (5) is provided between the lean liquid storage tank (4) and the acid gas absorption tower (2) to filter out impurities in the lean liquid; A rich liquid filter (8) is provided between the acidic gas absorption tower (2) and the pre-flash evaporation lean and rich liquid heat exchanger (9) to filter out impurities in the rich liquid.

7. The sulfur recovery pretreatment system according to claim 1, characterized in that, Also includes: The second cooling device is used to cool the H2S gas desorbed from the solvent regeneration tower (12); A cooling reflux tank (16) is used to reflux the liquid phase of the H2S gas cooled by the second cooling device back to the solvent regeneration tower (12), and the gas phase is transported to the sulfur recovery equipment and / or the acid gas absorption tower (2).

8. The sulfur recovery pretreatment system according to claim 7, characterized in that, The second cooling device includes a regeneration tower air cooler (14) and a regeneration tower aftercooler (15) connected in sequence along the conveying direction of the desorbed H2S gas.

9. The sulfur recovery pretreatment system according to claim 1, characterized in that, It also includes an acid gas separator (1), which is used to separate the sulfuric acid-rich gas into a liquid phase and then transport it to the acid gas absorption tower (2).

10. The sulfur recovery pretreatment system according to claim 1, characterized in that, It also includes a fuel gas separator (3) for separating the gas output from the acid gas absorption tower (2).

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