A system and method for preparing sodium hydrosulfide based on a hydrogen sulfide-containing sour gas

Abstract

This application relates to the field of sodium hydrosulfide production technology, and more particularly to a system and method for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas. The system includes: a sodium hydrosulfide reaction unit, comprising a sodium hydrosulfide reaction tower, a first isolation element, a second isolation element, a gas-liquid separator, and a sodium-containing alkaline solution inlet pipe. The first and second isolation elements divide the sodium hydrosulfide reaction tower into a first reaction section, a second reaction section, and a third reaction section. Each reaction section includes a gas-liquid contact section, and the gas-liquid separator is located at the top of the sodium hydrosulfide reaction tower; a jet circulation unit, including at least two ejectors, two separation devices, two sprayers, and two circulating cooling devices; and a sodium hydrosulfide discharge pipe connected to the discharge port of the first circulating cooling device. This system, through its three-stage countercurrent absorption, multi-stage jet circulation, secondary spraying within the separation devices, and optimized anti-channeling gas structure design, can significantly reduce the hydrogen sulfide content in the exhaust gas and improve the purity and yield of the sodium hydrosulfide product.

Description

Technical Field

[0001] This application relates to the field of sodium hydrosulfide production equipment technology, and in particular to a system and method for preparing sodium hydrosulfide based on acidic gas containing hydrogen sulfide. Background Technology

[0002] Oil refineries primarily employ processes such as the Claus sulfur recovery method and wet sulfuric acid production to treat sulfuric acid-containing gases generated during production. The Claus sulfur recovery method typically involves Claus sulfur preparation, Claus tail gas treatment (SCOT), solvent regeneration, tail gas incineration, and flue gas treatment. This process is lengthy, complex, and requires significant investment. The wet sulfuric acid production process includes acid gas incineration, SCR denitrification, SO2 catalytic conversion, hydration condensation, and tail gas treatment. However, this process demands stringent operating conditions and struggles to produce high-value fuming sulfuric acid, resulting in poor economic returns. In contrast, the sodium hydrosulfide production process offers advantages such as a simpler process and lower operating costs, effectively treating acidic gases generated during oil refining and chemical production. Furthermore, this sodium hydrosulfide production process generates sodium hydrosulfide, which has a wide range of applications, such as: in the dye industry for the synthesis of organic intermediates; in the leather industry for dehairing and tanning raw hides; in the fertilizer industry for removing monomeric sulfur from activated carbon desulfurizers; and in the production of synthetic fibers for dyeing with sulfurous acid. Additionally, sodium hydrosulfide is also a raw material for the preparation of products such as ammonium sulfide, sodium polysulfide, and sodium thiosulfate.

[0003] However, if hydrogen sulfide acid gas produced from oil refining and chemical processes is to be used as a feedstock in the sodium hydrosulfide production process, complex pretreatment operations are required to remove impurities. For example, a two-stage absorption-two-stage regeneration process can be used to purify hydrogen sulfide (H2S) from the acid gas. However, this process is complex, with expensive equipment and complicated operation, resulting in low purity sodium hydrosulfide. Therefore, to reduce the amount of by-reaction products generated in the sodium hydrosulfide product, it is necessary to reduce the hydrogen sulfide conversion rate. However, this method produces tail gas with a high hydrogen sulfide content, making direct emission difficult. Summary of the Invention

[0004] This application provides a system and method for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas, in order to solve the following technical problem: how to reduce the hydrogen sulfide content in the tail gas during the preparation of sodium hydrosulfide.

[0005] In a first aspect, embodiments of this application provide a system for preparing sodium hydrosulfide based on a hydrogen sulfide-containing acidic gas, the system comprising: A sodium hydrosulfide reaction unit includes a sodium hydrosulfide reaction tower, a first isolation element, a second isolation element, a gas-liquid separator, and a sodium-containing alkaline solution inlet pipe. The first and second isolation elements are disposed within the sodium hydrosulfide reaction tower to divide the tower into a first reaction section, a second reaction section, and a third reaction section. A first contact section is provided in the first reaction section, a second contact section is provided in the second reaction section, and a third contact section is provided in the third reaction section. The gas-liquid separator is fixedly connected to the top of the sodium hydrosulfide reaction tower. The outlet of the sodium-containing alkaline solution inlet pipe is connected to the upper part of the reaction tower and is located between the first contact section and the gas-liquid separator. The injection circulation unit includes a hydrogen sulfide-containing acidic gas inlet pipe, a first injector, a first separation device, a first sprayer, a first circulating cooling device, a third injector, a third separation device, a third sprayer, and a third circulating cooling device. The outlet of the hydrogen sulfide-containing acidic gas inlet pipe is connected to the inlet of the third injector. The outlet of the third injector is connected to the inlet of the third separation device. The bottom liquid outlet of the sodium hydrosulfide reaction tower is connected to the liquid outlet of the third separation device. The outlet of the third separation device is connected to the lower inlet of the third reaction section and the inlet of the third circulating cooling device. The outlet of the third circulating cooling device is connected to the inlet of the third injector and the upper inlet of the third reaction section. The third sprayer is located inside the third separation device, and the inlet of the third sprayer is connected to the bottom liquid outlet of the sodium hydrosulfide reaction tower. The inlet of the first injector is connected to the upper outlet of the second reaction section, the outlet of the first injector is connected to the inlet of the first separation device, the outlet of the first separation device is connected to the lower inlet of the first reaction section and the inlet of the first circulating cooling device, the outlet of the first circulating cooling device is connected to the inlet of the first injector and the upper inlet of the first reaction section, the upper inlet of the first reaction section is symmetrically arranged with the sodium-containing alkaline solution inlet pipe, the first sprayer is arranged in the first separation device, and the inlet of the first sprayer is connected to the outlet of the first reaction section. A sodium hydrosulfide discharge pipe, the inlet of which is connected to the outlet of the first circulating cooling device.

[0006] Optionally, the spray circulation unit further includes a second injector, a second separation device, a second sprayer, and a second circulating cooling device. The inlet of the second injector is connected to the upper outlet of the second reaction section, the outlet of the second injector is connected to the inlet of the second separation device, the outlet of the second separation device is connected to the lower inlet of the second reaction section and the inlet of the second circulating cooling device, and the outlet of the second circulating cooling device is connected to the inlet of the second injector and the upper inlet of the second reaction section. The second sprayer is disposed inside the second separation device, and the inlet of the second sprayer is connected to the bottom liquid outlet of the second reaction section.

[0007] Optionally, the second separation device includes a second separation tank and a second liquid chamber, a second gas chamber, and a second coalescer disposed within the second separation tank. The inlet of the second separation tank is connected to the outlet of the second ejector, and the second coalescer is disposed at one end of the second separation tank. In accordance with the gas diffusion direction, the second liquid chamber is disposed downstream of the second coalescer, and the second gas chamber is symmetrically disposed with respect to the second liquid chamber. The outlet of the second gas chamber is connected to the lower inlet of the second reaction section, and the outlet of the second liquid chamber is connected to the second circulating cooling device.

[0008] Optionally, the second circulating cooling device includes: a second circulating pump and a second cooler, wherein the inlet of the second circulating pump is connected to the outlet of the second liquid tank, the outlet of the second circulating pump is connected to the inlet of the second cooler, and the outlet of the second cooler is connected to the inlet of the second injector and the upper inlet of the second reaction section, respectively.

[0009] Optionally, the first separation device includes a first separation tank and a first liquid chamber, a first gas chamber, and a first coalescer disposed within the first separation tank. The inlet of the first separation tank is connected to the outlet of the first ejector, and the first coalescer is disposed at one end of the first separation tank. According to the gas diffusion direction, the first liquid chamber is disposed downstream of the first coalescer, and the first gas chamber is symmetrically disposed with respect to the first liquid chamber. The outlet of the first gas chamber is connected to the lower inlet of the first reaction section, and the outlet of the first liquid chamber is connected to the second circulating cooling device. The third separation device includes a third separation tank and a third liquid chamber, a third gas chamber, and a third coalescer disposed within the third separation tank. The inlet of the third separation tank is connected to the outlet of the third ejector, and the third coalescer is disposed at one end of the third separation tank. In accordance with the gas diffusion direction, the third liquid chamber is disposed downstream of the third coalescer, and the third gas chamber is symmetrically disposed with respect to the third liquid chamber. The outlet of the third gas chamber is connected to the lower inlet of the third reaction section, and the outlet of the third liquid chamber is connected to the second circulating cooling device.

[0010] Optionally, the first circulating cooling device includes a first circulating pump and a first cooler. The inlet of the first circulating pump is connected to the outlet of the first liquid tank, the outlet of the first circulating pump is connected to the inlet of the first cooler, and the outlet of the first cooler is connected to the inlet of the first injector and the upper inlet of the first reaction section, respectively. The third circulating cooling device includes a third circulating pump and a third cooler. The inlet of the third circulating pump is connected to the outlet of the third liquid tank, and the outlet of the third circulating pump is connected to the inlet of the third cooler. The outlet of the third cooler is connected to the inlet of the third injector and the upper inlet of the third reaction section, respectively.

[0011] Optionally, the sodium hydrosulfide reaction unit further includes: a first downcomer and a second downcomer, wherein the first downcomer penetrates the first isolation element and a gas-blocking sealing plate is provided at the bottom end of the first downcomer to isolate gas exchange between the first reaction section and the second reaction section; the second downcomer penetrates the second isolation chamber and a gas-blocking sealing plate is provided at the bottom end of the second downcomer to isolate gas exchange between the second reaction section and the third reaction section.

[0012] Optionally, the formula for calculating the diameter of the first downcomer or the second downcomer is: Equation 1; A=0.785D 2 Equation 2; In Equation 1, f is the coefficient of friction; when D ≤ 0.015m, f is 0.027; when D ≥ 0.100m, f is 0.017; when 0.015m < D < 0.100m, f satisfies the following: Equation 3; In Equations 1, 2, and 3, Q represents the liquid volumetric flow rate through the first downcomer or the second downcomer, in m³ / s. 3 / s;C dis the flow coefficient, with a value of 0.65; A is the cross-sectional area of ​​the first downcomer or the second downcomer, in meters. 2 h represents the vertical height difference between the first downcomer and the second downcomer, in meters (m); g represents the acceleration due to gravity, with a value of 9.81 m / s². 2 D is the diameter of the first downcomer or the second downcomer, in meters; L is the length of the first downcomer or the second downcomer, in meters.

[0013] Optionally, the sodium hydrosulfide reaction unit further includes: a first distributor, a second distributor, and a third distributor, wherein the first distributor is disposed between the sodium-containing alkali inlet pipe and the first contact section; the second distributor is disposed above the second contact section; and the third distributor is disposed between the upper feed inlet of the third reaction section and the third contact section.

[0014] In a second aspect, embodiments of this application provide a method for preparing sodium hydrosulfide based on a hydrogen sulfide-containing acidic gas, the method being adapted to the system described in the first aspect, the method comprising: The sodium-containing alkaline solution is divided into three stages: a first-stage sodium-containing alkaline solution, a second-stage sodium-containing alkaline solution, and a third-stage sodium-containing alkaline solution. A portion of the three sections containing sodium-containing alkaline solution and hydrogen sulfide-containing acidic gas are mixed by a third injection to obtain a third gas-liquid two-phase mixture; The third gas-liquid two-phase mixture and a portion of the three sodium-containing alkaline solutions are subjected to a third countercurrent contact reaction to obtain a third mixed reaction product. The third mixed reaction product is subjected to a third coalescence separation to obtain a third discharged purified gas and a three-stage circulating alkaline solution. The three-stage circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a three-stage primary circulating alkaline solution, a three-stage secondary circulating alkaline solution, and sodium hydrosulfide product; wherein, the three-stage secondary circulating alkaline solution is returned to the third spray mixing process as a supplementary feed for the three-stage sodium-containing alkaline solution; The third effluent purified gas is subjected to a third gas-liquid contact reaction using the three-stage primary circulating alkaline solution and the remaining three-stage sodium-containing alkaline solution to obtain three-stage effluent alkaline solution and third effluent purified gas; wherein, the three-stage effluent alkaline solution is returned to the third countercurrent contact reaction as a supplement to the three-stage sodium-containing alkaline solution. The third discharge purified gas and part of the second stage sodium-containing alkaline solution are mixed by a second injection to obtain a second gas-liquid two-phase mixture. The second gas-liquid two-phase mixture and a portion of the second sodium-containing alkaline solution are subjected to a second countercurrent contact reaction to obtain a second mixed reaction product. The second mixed reaction product is subjected to a second coalescence separation to obtain a second discharged purified gas and a second-stage circulating alkaline solution. The two-stage circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a two-stage primary circulating alkaline solution and a two-stage secondary circulating alkaline solution; wherein, the two-stage secondary circulating alkaline solution is returned to the second spray mixing as a supplementary material for the two-stage sodium-containing alkaline solution; The second-stage primary circulating alkali solution and the remaining second-stage sodium-containing alkali solution are used in a second gas-liquid contact reaction with the second effluent purified gas to obtain a second-stage effluent alkali solution, a third-stage feed alkali solution, and a second effluent purified gas. The third-stage feed alkali solution is mixed with the third-stage primary circulating alkali solution and returned to the third gas-liquid contact reaction as the third-stage primary circulating alkali solution. A portion of the second-stage effluent alkali solution is returned to the second countercurrent contact reaction as a supplement to the second-stage sodium-containing alkali solution. The remaining second-stage effluent alkali solution is used as a supplement to the third-stage sodium-containing alkali solution. The second discharged purified gas and a portion of the sodium-containing alkaline solution in the first injection are mixed to obtain a first gas-liquid two-phase mixture. The first gas-liquid two-phase mixture and a portion of the sodium-containing alkaline solution are subjected to a first countercurrent contact reaction to obtain a first mixed reaction product. The first mixed reaction product is subjected to a first coalescence separation to obtain a first discharge purified gas and a first-stage circulating alkaline solution. The circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a primary circulating alkaline solution and a secondary circulating alkaline solution; wherein, the secondary circulating alkaline solution is returned to the first spray mixing process as a supplement to the sodium-containing alkaline solution. The first-stage circulating alkali solution and the remaining first-stage sodium-containing alkali solution are used to perform a first gas-liquid contact reaction on the first-stage effluent purified gas to obtain a first-stage effluent alkali solution, a second-stage feed alkali solution, and tail gas. The second-stage feed alkali solution is mixed with the second-stage first-stage circulating alkali solution and returned to the second gas-liquid contact reaction as the second-stage first-stage circulating alkali solution. A portion of the first-stage effluent alkali solution is returned to the first countercurrent contact reaction as a supplement to the first-stage sodium-containing alkali solution. The remaining first-stage effluent alkali solution is used as a supplement to the second-stage sodium-containing alkali solution.

[0015] Optionally, the temperatures of the first, second, and third injection mixtures are 50°C to 80°C, the times of the first, second, and third injection mixtures are 0.005s to 0.400s, and the pressures of the first, second, and third injection mixtures are greater than or equal to 25kPa.

[0016] Optionally, the temperatures of the first gas-liquid contact reaction, the second gas-liquid contact reaction, and the third gas-liquid contact reaction are all between 45°C and 75°C; and the pressures of the first gas-liquid contact reaction, the second gas-liquid contact reaction, and the third gas-liquid contact reaction are all greater than or equal to 5 kPa.

[0017] Optionally, the flow rate of the three-stage primary circulating alkaline solution is 0.5 to 6.0 times the flow rate of the sodium-containing alkaline solution, and the flow rate of the three-stage secondary circulating alkaline solution is 1.5 to 15.0 times the flow rate of the sodium-containing alkaline solution; and / or The flow rate of the primary circulating alkaline solution in the second stage is 0.5 to 6.0 times the flow rate of the sodium-containing alkaline solution, and the flow rate of the secondary circulating alkaline solution in the second stage is 1.5 to 15.0 times the flow rate of the sodium-containing alkaline solution; and / or The flow rate of the first-stage circulating alkaline solution is 0.5 to 6.0 times that of the sodium-containing alkaline solution, and the flow rate of the second-stage circulating alkaline solution is 1.5 to 15.0 times that of the sodium-containing alkaline solution.

[0018] Optionally, the flow rates of the gas-liquid two-phase mixture in the first countercurrent contact reaction, the second countercurrent contact reaction, and the third countercurrent contact reaction are 1.0 m / s to 8.0 m / s, respectively, and the times of the first countercurrent contact reaction, the second countercurrent contact reaction, and the third countercurrent contact reaction are 0.5 s to 15 s, respectively.

[0019] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas. The system first divides a sodium hydrosulfide reaction tower into a first reaction section, a second reaction section, and a third reaction section using a first and second separator. A sodium-containing alkaline solution inlet pipe is placed at the top of the sodium hydrosulfide reaction tower. Simultaneously, the hydrogen sulfide-containing acidic gas enters the sodium hydrosulfide reaction tower through a third injector and a third separation device. In the first contact section of the first reaction section, the second contact section of the second reaction section, and the third contact section of the third reaction section, the hydrogen sulfide-containing acidic gas and the sodium-containing alkaline solution undergo a counter-current gas-liquid contact reaction. This achieves a gradient absorption system that prioritizes the treatment of high-concentration hydrogen sulfide gas while deeply purifying low-concentration gas, promoting a full reaction between the hydrogen sulfide-containing acidic gas and the sodium-containing alkaline solution to effectively reduce the hydrogen sulfide content of the hydrogen sulfide-containing acidic gas. Furthermore, for the gas-liquid contact… The unreacted hydrogen sulfide gas and the multi-stage effluent alkaline solution formed during the reaction are recycled through the first and third injectors of the spray circulation unit, as well as the corresponding first and third circulating cooling devices. This further reduces the hydrogen sulfide content in the hydrogen sulfide gas and forms a circulating alkaline solution. This circulating alkaline solution is recycled back to the first and second separation devices through the first and third sprayers, respectively, and reacts countercurrently with the gas-liquid two-phase mixture formed by the pressurization of the first and third injectors, forming a multi-stage local circulation of "separation-spraying-reabsorption", which further reduces the hydrogen sulfide content in the hydrogen sulfide gas. In addition, the gas at the top of the sodium hydrosulfide reaction tower can be separated into liquid phase through a gas-liquid separator, thereby obtaining pure tail gas with low hydrogen sulfide content. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the actual structure of a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas, provided in Embodiment 1 of this application. Figure 2 A schematic flowchart illustrating a method for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas, provided for an embodiment of this application; Figure 3 for Figure 2 The continuation; Among them, 1-sodium hydrosulfide reaction tower, 11-first reaction section, 111-first distributor, 112-first contact section, 113-first isolation element, 114-first downcomer, 115-gas-liquid separator, 12-second reaction section, 121-second distributor, 122-second contact section, 123-second isolation element, 124-second downcomer, 13-third reaction section, 131-third distributor, 132-third contact section, 14-sodium-containing alkaline solution inlet pipe, 2-jet circulation unit, 21-first injector, 22-second injector, 23-third injector, 24-hydrogen sulfide-containing acidic solution 25 - Gas inlet pipe, 26 - First sprayer, 27 - Second sprayer, 31 - Third sprayer, 311 - First separator, 312 - First liquid tank, 313 - First gas tank, 32 - Second separator, 321 - Second coalescer, 322 - Second liquid tank, 323 - Second gas tank, 33 - Third separator, 331 - Third coalescer, 332 - Third liquid tank, 333 - Third gas tank, 41 - First circulating pump, 42 - Second circulating pump, 43 - Third circulating pump, 51 - First cooler, 52 - Second cooler, 53 - Third cooler, 6 - Sodium hydrosulfide discharge pipe. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] The range descriptions used in this application, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "comprising" and others used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships involved in this document, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained by purchasing from the market or by existing methods.

[0025] It should be noted that the production of sodium hydrosulfide using existing technology requires a two-stage absorption-two-stage regeneration pretreatment of the hydrogen sulfide-containing acidic gas. The process flow includes: the hydrogen sulfide acidic gas first comes into countercurrent contact with a first-stage lean amine solution in a first-stage absorption tower, where the hydrogen sulfide in the acidic gas is selectively absorbed by the first-stage lean amine solution to obtain a first-stage rich solution; then the first-stage rich solution enters a first-stage regeneration tower for regeneration, and the first-stage regeneration gas at the top of the first-stage regeneration tower enters a second-stage absorption tower and comes into countercurrent contact with a second-stage lean amine solution, where the hydrogen sulfide in the first-stage regeneration gas is absorbed by the second-stage lean amine solution to obtain a second-stage rich solution; then the second-stage rich solution enters a second-stage regeneration tower for further regeneration, and the gas at the top of the second-stage regeneration tower is the purified hydrogen sulfide gas. Finally, the purified hydrogen sulfide gas is neutralized with a sodium-containing alkaline solution to form sodium hydrosulfide. This process flow is relatively complex, with high equipment and operating costs. In addition, to improve the purity of sodium hydrosulfide, the recovery rate of hydrogen sulfide needs to be reduced, which results in a low yield of sodium hydrosulfide.

[0026] Figure 1 An exemplary schematic diagram of the actual structure of a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas is shown in an embodiment of this application. like Figure 1 As shown in the embodiment of this application, a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas is provided. The system includes: The sodium hydrosulfide reaction unit includes a sodium hydrosulfide reaction tower 1, a first isolation element 113, a second isolation element 123, a gas-liquid separator 115, and a sodium-containing alkaline solution inlet pipe 14. The first isolation element 113 and the second isolation element 123 are disposed inside the sodium hydrosulfide reaction tower 1 to divide the sodium hydrosulfide reaction tower 1 into a first reaction section 11, a second reaction section 12, and a third reaction section 13. A first contact section 112 is disposed in the first reaction section 11, a second contact section 122 is disposed in the second reaction section 12, and a third contact section 132 is disposed in the third reaction section 13. The gas-liquid separator 115 is fixedly connected to the top of the sodium hydrosulfide reaction tower 1. The outlet of the sodium-containing alkaline solution inlet pipe 14 is connected to the upper part of the sodium hydrosulfide reaction tower 1, and the outlet of the sodium-containing alkaline solution inlet pipe 14 is disposed between the first contact section 112 and the gas-liquid separator 115. The injection circulation unit 2 includes a hydrogen sulfide acid gas inlet pipe 24, a first injector 21, a first separation device, a first sprayer 25, a first circulating cooling device, a third injector 23, a third separation device, a third sprayer 27, and a third circulating cooling device. The outlet of the hydrogen sulfide acid gas inlet pipe 24 is connected to the inlet of the third injector 23. The outlet of the third injector 23 is connected to the inlet of the third separation device. The bottom liquid outlet of the sodium hydrosulfide reaction tower 1 is connected to the liquid outlet of the third separation device. The outlet of the third separation device is connected to the lower inlet of the third reaction section 13 and the inlet of the third circulating cooling device. The outlet of the third circulating cooling device is connected to the inlet of the third injector 23 and the upper inlet of the third reaction section 13. The third sprayer 27 is located inside the third separation device. The inlet of the third sprayer 27 is connected to the bottom liquid outlet of the sodium hydrosulfide reaction tower 1. The inlet of the first injector 21 is connected to the upper outlet of the second reaction section 12, the outlet of the first injector 21 is connected to the inlet of the first separation device, the outlet of the first separation device is connected to the lower inlet of the first reaction section 11 and the inlet of the first circulating cooling device, the outlet of the first circulating cooling device is connected to the inlet of the first injector 21 and the upper inlet of the first reaction section 11, the upper inlet of the first reaction section 11 is symmetrically arranged with the sodium-containing alkaline solution inlet pipe 14, the first sprayer 25 is arranged in the first separation device, and the inlet of the first sprayer 25 is connected to the liquid outlet of the first reaction section 11. Sodium hydrosulfide discharge pipe 6, the inlet of which is connected to the outlet of the first circulating cooling device.

[0027] It should be noted that the first isolation member 113 and the second isolation member 123 can both be elliptical heads, flat cap heads, or other types of isolation inner members. Depending on the actual isolation situation, the first isolation member 113 and the second isolation member 123 can be elliptical heads.

[0028] It should be noted that in the first reaction section 11, the sodium-containing alkaline solution enters the first distributor 111 and the gas-liquid separator 115 of the first contact section 11 through the sodium-containing alkaline solution inlet pipe 14. The molar flow rate S1 of sodium hydroxide in the sodium-containing alkaline solution and the molar flow rate S2 of hydrogen sulfide in the hydrogen sulfide acid gas can satisfy: S1:S2=1:1.

[0029] It should be noted that the sodium-containing alkaline solution in the sodium-containing alkaline solution inlet tube 14 can be an aqueous solution of sodium hydroxide with a temperature of 10℃ to 40℃ and a pressure of 0.3MPa to 3.5MPa. The mass of sodium hydroxide in the aqueous solution can be 25% to 50% of the total mass of the aqueous solution.

[0030] It should be noted that the hydrogen sulfide-containing acidic gas introduced through the hydrogen sulfide-containing acidic gas inlet pipe 24 can be an acidic gas with a temperature of 10℃ to 90℃ and a pressure of 0.01MPa to 3.5MPa. Besides the main component hydrogen sulfide, this hydrogen sulfide-containing acidic gas may also contain impurities such as water vapor, carbon dioxide, ammonia, nitrogen, and hydrocarbons. This hydrogen sulfide-containing acidic gas can be acidic gas from acidic water stripping, solvent regeneration acidic gas, or hydrogen sulfide-containing natural gas, etc.

[0031] It should be noted that the sodium-containing alkaline solution in the sodium-containing alkaline solution inlet pipe 14 can come into countercurrent contact with the first effluent purified gas from the first gas chamber 313 in the first separation device within the first contact section 112. During the countercurrent contact process, mass transfer, heat transfer, and reaction occur, including the reaction to generate sodium hydrosulfide (NaHS) as shown in reaction formula (1): Na2S(aq) + H2S(aq)→2NaHS(aq) , (1); The reaction process shown in reaction formula (1) also includes a side reaction that produces sodium sulfide (Na2S), namely reaction formula (2): H2S(aq)+2NaOH(aq)→Na2S(aq)+2H2O, (2); Both reactions shown in equation (1) and equation (2) are exothermic reactions. When the molar ratio of sodium hydroxide in the sodium-containing alkaline solution to hydrogen sulfide in the hydrogen sulfide-containing acidic gas is greater than 1.5:1, the reaction shown in equation (2) is dominant. When the molar ratio of sodium hydroxide in the sodium-containing alkaline solution to hydrogen sulfide in the hydrogen sulfide-containing acidic gas is less than 1.05:1, the reaction shown in equation (1) is dominant. When the molar ratio of sodium hydroxide in the sodium-containing alkaline solution to hydrogen sulfide in the hydrogen sulfide-containing acidic gas is in the range of 1.05:1 to 1.5:1, both reactions (1) and (2) are the main reactions.

[0032] It should be noted that when the acidic gas containing hydrogen sulfide contains carbon dioxide, sodium hydroxide in the sodium-containing alkaline solution will also undergo side reactions with carbon dioxide, including the side reaction to form sodium bicarbonate as shown in reaction (3): CO2(aq)+NaOH(aq)→NaHCO3(aq), (3), And including side reactions that produce sodium carbonate, as shown in reaction (4): NaHCO3(aq)+NaOH(aq)→Na2CO3(aq)+H2O, (4); The existence of these side reactions not only increases the consumption of sodium-containing alkaline solution, but also forms a large amount of waste alkaline solution containing carbonates. Moreover, these carbonates will also pollute the quality of sodium hydrosulfide products. Therefore, it is crucial to improve the selectivity of hydrogen sulfide absorption and reduce the formation of carbonates. Based on the reaction mechanism that the absorption rate of hydrogen sulfide by sodium-containing alkaline solution is greater than that of carbon dioxide by sodium-containing alkaline solution, this application takes the following measures: (1) Multi-stage reaction, for example, splitting the overall reaction into 6-stage, 9-stage, and 12-stage reactions, reducing the reaction time of each stage reaction, thereby reducing the amount of carbon dioxide gas absorbed by sodium hydroxide solution. For example, the reactants undergo 6-stage and 9-stage reactions in the first contact section 112, the first injector 21, the first separation device, and the subsequent third contact section 132, the third injector 23, and the third separation device. As the number of reaction stages increases, the reaction time of each stage can be appropriately reduced while ensuring the quality of the product. This reduces the probability of carbon dioxide being absorbed by the sodium hydroxide solution, thereby reducing the amount of sodium carbonate and / or sodium bicarbonate generated. Although the conversion rate of hydrogen sulfide in the acidic gas containing hydrogen sulfide decreases slightly during each stage of reaction, the total conversion rate of hydrogen sulfide in the acidic gas containing hydrogen sulfide remains unchanged and still meets the requirements of product quality. (2) Optimize operating conditions, such as increasing the circulation volume of sodium-containing alkaline solution and controlling the pH value and reaction temperature of the circulating alkaline solution under suitable operating conditions to suppress the generation of sodium carbonate and sodium bicarbonate.

[0033] It should be noted that after the sodium-containing alkaline solution absorbs hydrogen sulfide from the first discharged purified gas, it can be buffered at the bottom of the first reaction section 11 to separate the carried gas. Then, the sodium-containing alkaline solution that has absorbed hydrogen sulfide is split into two parts. One part can be used as the first discharged alkaline solution and enter the first separation tank 31 in the first separation device, and the other part can be used as the second fed alkaline solution and enter the first downcomer 114.

[0034] It should be noted that the first effluent alkaline solution entering the first separation device and the first gas-liquid two-phase mixture sprayed upward through the first injector 21 will undergo a series of operations such as contact, collision, mixing, heat transfer and mass transfer in the first separation tank 31 of the first separation device, and promote the further reaction of hydrogen sulfide in the first gas-liquid two-phase mixture with sodium-containing alkaline substances (sodium hydroxide and / or sodium sulfide) in the first effluent alkaline solution to generate sodium hydrosulfide.

[0035] It should be noted that a first distributor 111 can be set in the first reaction section 11, and a first-stage circulating alkali inlet can be set in the first reaction section 11. The first-stage circulating alkali inlet can be located between the gas-liquid separator 115 and the first distributor 111. The first-stage circulating alkali from the first separation device can enter the first reaction section 11 through the first-stage circulating alkali inlet. The first-stage circulating alkali can share the first distributor 111 with the sodium-containing alkali introduced by the sodium-containing alkali inlet pipe 14. The first-stage circulating alkali and the sodium-containing alkali can be fully mixed in the first distributor 111 to form a first mixed liquid. After being buffered and evenly distributed by the first distributor 111, the first mixed liquid enters the first contact section 112 from top to bottom and comes into countercurrent contact with the first discharge purified gas of the first gas chamber 313 that enters the first contact section 112 from bottom to top. During the contact process, the first mixed liquid absorbs part of the hydrogen sulfide in the first discharge purified gas of the first gas chamber 313 and undergoes a reaction including reaction formula (1) and reaction formula (2). After the first mixture absorbs part of the hydrogen sulfide in the first discharge purified gas of the first gas chamber 313, it continues to flow downward to the bottom of the first reaction section 11 and is buffered at the bottom of the first reaction section 11 to separate the carried gas. Then the first mixture that has absorbed hydrogen sulfide is split into two parts: one part is the first discharge alkaline solution that enters the first separation device, and the other part is the second feed alkaline solution that enters the second reaction section 12.

[0036] It should be noted that the first injector 21 consists of four parts: a nozzle, a receiving chamber, a mixing chamber, and a diffusion chamber. After being pressurized by the first circulating pump 41 in the first separation device, the secondary circulating alkaline solution enters the nozzle of the first injector 21 and generates a high flow velocity after being sprayed through the nozzle. The high flow velocity of the secondary circulating alkaline solution can form a low-pressure zone around the nozzle, so the second discharge purified gas from the top of the second reaction section 12 can be drawn into the receiving chamber. In the receiving chamber, the second discharge purified gas and the secondary circulating alkaline solution can be initially mixed and then enter the mixing chamber, where they are fully mixed to form turbulence. During this process, the secondary circulating alkaline solution can absorb some of the hydrogen sulfide in the second discharge purified gas and undergo reactions including reaction formula (1) and reaction formula (2). Then, the gas-liquid two-phase mixture at the outlet of the mixing chamber can enter the diffusion chamber as the first gas-liquid two-phase mixture. Based on the design of the diffusion chamber with gradually increasing diameter, the flow velocity of the first gas-liquid two-phase mixture gradually decreases, and the kinetic energy of the first gas-liquid two-phase mixture is converted into pressure energy, which increases the outlet pressure of the first gas-liquid two-phase mixture in the diffusion chamber. This avoids the use of pressurization equipment, simplifies the process flow, and reduces equipment costs and operating expenses. The first injector 21 can quickly complete the reaction including reaction formula (1) and reaction formula (2) within 0.005s to 0.400s, which is beneficial to reduce the by-reaction products such as sodium carbonate and sodium bicarbonate in sodium hydrosulfide products.

[0037] It should be noted that after the hydrogen sulfide in the first discharge purified gas in the first gas tank 313 is absorbed by the mixture of sodium-containing alkaline solution and a first-stage circulating alkaline solution in the first contact section 112, the volume fraction of hydrogen sulfide in the first discharge purified gas is less than or equal to 0.000100 or meets other specially specified index requirements. It then flows directly upward to the gas-liquid separator 115, where more than 99.9% of the liquid phase components it carries are removed and discharged as tail gas from the entire system.

[0038] It should be noted that the gas-liquid separator 115 is installed at a height higher than the sodium alkali inlet pipe 14 and the first-stage circulating alkali inlet, with a height difference of at least 0.3m. The type of equipment used in the gas-liquid separator 115 may include at least one of wire mesh demisters, baffle plate demisters, cyclone tube demisters, and fiber bed demisters.

[0039] It should be noted that the mass transfer, heat transfer, and reaction components in the first contact section 112, the second contact section 122, and the third contact section 132 are trays and / or packing, respectively. If trays are used in the first contact section 112, the second contact section 122, and the third contact section 132, each contact section is equipped with 3 to 6 trays, and the outer diameter of the trays must be designed to meet the processing load requirements of the hydrogen sulfide-containing acidic gas. Based on the volumetric flow meter under standard conditions (0℃, 101.325kPa), the processing capacity per square meter of tray cross-sectional area is 200 Nm³. 3 / h to 4000Nm 3 The design is for a hydrogen sulfide-containing acidic gas concentration of / h; if the first contact section 112, the second contact section 122, and the third contact section 132 use packing, each contact section can be selected as either random packing or structured packing, with a packing layer height of 1.2m to 3.6m, and the outer diameter of the stockpile bed is calculated based on a cross-sectional area of ​​400 Nm per square meter. 3 / h to 4000Nm 3 The design is based on a capacity of / h for hydrogen sulfide-containing acidic gas. When the volume fraction of carbon dioxide in the hydrogen sulfide-containing acidic gas is greater than 5%, regardless of whether trays or packing are used, a uniform capacity of 4000 Nm² per square meter of cross-sectional area is applied. 3 The system is designed to produce a hydrogen sulfide-containing acidic gas at a rate of / h, thereby shortening the reaction time in the first contact section 112, the second contact section 122, and the third contact section 132. This effectively suppresses the formation of by-products such as sodium carbonate and sodium bicarbonate, ensuring that the mass fraction of by-products such as sodium carbonate and sodium bicarbonate in the sodium hydrosulfide product is less than 0.5%.

[0040] It should be noted that the operating temperature of the first reaction section 11 can be from 45°C to 75°C, and the operating pressure of the first reaction section 11 is greater than or equal to 5 kPaG; the operating temperature of the first ejector 21 can be from 50°C to 80°C, and the difference between the outlet pressure of the first ejector 21 and the operating pressure of the first separation device can be greater than or equal to 15 kPa. The outlet pressure of the first ejector 21 can also be the sum of the operating pressure of the first separation device and the pipeline pressure drop of the first gas-liquid two-phase mixture from the first ejector 21 to the first separation device. In order to ensure the stable operation of the first ejector 21 and the first separation device, the outlet pressure of the first ejector 21 needs to be maintained at a high value, so as to provide sufficient driving force for the material to flow downstream.

[0041] It should be noted that after a section of the alkali solution is discharged from the lower part of the first reaction section 11, it enters the upper part of the first separation tank 31 and is evenly sprayed into the lower part of the first separation tank 31 of the first separation device by the first sprayer 25 under the action of gravity. It is set that there is a liquid level difference or height difference between the discharge port of the lower part of the first reaction section 11 and the feed port of the first separation tank 31. These liquid level differences or height differences can be from 0.2m to 12.0m, which can provide the necessary pressure for atomization of the nozzle of the first sprayer 25.

[0042] It should be noted that the first sprayer 25 can use a gravity-fed atomizing nozzle distributor. This gravity-fed atomizing nozzle distributor is a liquid distribution device that combines gravity drive and atomization technology. Without the need for external driving force, the liquid passes through the nozzle of the gravity-fed atomizing nozzle distributor to form fine droplets, which are atomized and sprayed uniformly downwards. The nozzle of the gravity-fed atomizing nozzle distributor can include at least one of pressure centrifugal atomizing nozzles, impact nozzles, and porous sintered nozzles. The orifice diameter of the nozzle of the gravity-fed atomizing nozzle distributor can be from 0.5 mm to 3 mm, the spray cone angle of the gravity-fed atomizing nozzle distributor can be from 30° to 120°, the particle size of the atomized liquid droplets of the gravity-fed atomizing nozzle distributor can be from 50 μm to 500 μm, and the atomization pressure required by the gravity-fed atomizing nozzle distributor can be from 0.02 MPa to 0.1 MPa.

[0043] It should be noted that the outlet of the first injector 21 can be equipped with a tubular gas-liquid distributor, and the main pipe and branch pipe of the tubular gas-liquid distributor are provided with upward spray nozzles. The diameter of the nozzles can be 2mm to 10mm, and the flow velocity of the first gas-liquid two-phase mixture at the nozzle of the tubular gas-liquid distributor can be 1.0m / s to 8.0m / s.

[0044] It should be noted that a second distributor 121 can be installed in the second reaction section 12, and the second distributor 121 is located above the second contact reaction section. A two-stage primary circulating alkali inlet can also be installed in the second reaction section 12, and the two-stage primary circulating alkali inlet is located between the outlet of the second discharge purified gas and the second distributor 121. The second-stage primary circulating alkaline solution from the second liquid tank 322 enters the second reaction section 12 through the second-stage primary circulating alkaline solution inlet, and shares the second distributor 121 with the second-stage feed alkaline solution from the bottom of the first reaction section 11. The second-stage primary circulating alkaline solution and the second-stage feed alkaline solution are fully mixed in the second distributor 121 to form a second mixture. The second mixture enters the second contact section 122 from top to bottom and has a countercurrent contact with the second discharge purified gas from the second gas tank 323 that enters the second contact section 122 from bottom to top. During the countercurrent contact process, the second mixture can absorb part of the hydrogen sulfide in the second discharge purified gas and undergo a reaction including reaction formula (1) and reaction formula (2). After the second mixture absorbs some of the hydrogen sulfide in the second discharged purified gas, it continues to flow from top to bottom to the bottom of the second reaction section 12, where it is buffered to separate the carried gas. The hydrogen sulfide-absorbed second mixture is then split into two parts: one part becomes the second-stage discharged alkaline solution entering the second separation device, and the other part becomes the third-stage feed alkaline solution entering the third reaction section 13. Meanwhile, the hydrogen sulfide in the second discharged purified gas, after being absorbed by the second mixture in the second contact section 122, can be discharged from the upper part of the second reaction section 12, and the second discharged purified gas is introduced into the receiving chamber of the first injector 21.

[0045] It should be noted that the second contact segment 122 has the same structure, size and type as the first contact segment 112.

[0046] It should be noted that the second-stage alkali solution enters the upper part of the second separation device from the lower outlet of the second reaction section 12 and is evenly sprayed into the second separation device through the second sprayer 26. At this time, the second-stage alkali solution from the second reaction section 12 is sprayed downward, while the second gas-liquid two-phase mixture from the second sprayer 22 is sprayed upward. The second-stage alkali solution and the second gas-liquid two-phase mixture undergo a series of operations of contact, collision, mixing, heat transfer and mass transfer in the second separation tank 32 of the second separation device, and promote the further reaction of hydrogen sulfide in the second gas-liquid two-phase mixture with sodium-containing alkaline substances (sodium hydroxide and / or sodium sulfide) in the second-stage alkali solution to generate sodium hydrosulfide.

[0047] It should be noted that the second injector 22 consists of four parts: a nozzle, a receiving chamber, a mixing chamber, and a diffusion chamber. After being pressurized by the second circulating pump 42 in the second separation device, the second-stage secondary circulating alkaline solution enters the nozzle of the second injector 22 and generates a high flow velocity after being sprayed through the nozzle. The high flow velocity of the second-stage secondary circulating alkaline solution can form a low-pressure zone around the nozzle, so the third discharge purified gas from the top of the third reaction section 13 can be drawn into the receiving chamber. In the receiving chamber, the third discharge purified gas and the second-stage secondary circulating alkaline solution can be initially mixed and then enter the mixing chamber, where they are fully mixed to form turbulence. During this process, the second-stage secondary circulating alkaline solution can absorb part of the hydrogen sulfide in the third discharge purified gas and undergo reactions including reaction formula (1) and reaction formula (2). Then, the gas-liquid two-phase mixture at the outlet of the mixing chamber can enter the diffusion chamber as the second gas-liquid two-phase mixture. Based on the design of the diffusion chamber with a gradually increasing diameter, the flow velocity of the second gas-liquid two-phase mixture gradually decreases, and the kinetic energy of the second gas-liquid two-phase mixture is converted into pressure, increasing the outlet pressure of the second gas-liquid two-phase mixture in the diffusion chamber. This avoids the use of pressurization equipment, simplifies the process flow, and reduces equipment costs and operating expenses. The second injector 22 can quickly complete the reaction including reaction formula (1) and reaction formula (2) within 0.005s to 0.400s, which is beneficial to reduce the by-reaction products such as sodium carbonate and sodium bicarbonate in sodium hydrosulfide products.

[0048] It should be noted that the operating temperature of the second reaction section 12 can be from 45°C to 75°C, and the operating pressure of the second reaction section 12 is greater than or equal to 5 kPaG; the operating temperature of the second ejector 22 is from 50°C to 80°C, and the difference between the outlet pressure of the second ejector 22 and the operating pressure of the second separation device can be greater than or equal to 15 kPa. The outlet pressure of the second ejector 22 can also be the sum of the operating pressure of the second separation device and the pipeline pressure drop of the second gas-liquid two-phase mixture from the second ejector 22 to the second separation device. In order to ensure the stable operation of the second ejector 22 and the second separation device, the outlet pressure of the second ejector 22 needs to be maintained at a high value, so as to provide sufficient driving force for the material to flow downstream.

[0049] It should be noted that after the second-stage alkali solution is discharged from the lower part of the second reaction section 12, it enters the upper part of the second separation tank 32 and is evenly sprayed into the lower part of the second separation tank 32 of the second separation device through the second sprayer 26 under the action of gravity. It is set that there is a liquid level difference or height difference between the second-stage alkali solution from the lower outlet of the second reaction section 12 and the inlet of the second separation tank 32. These liquid level differences or height differences can be from 0.2m to 12.0m, which can provide the necessary pressure for atomization of the nozzle of the second sprayer 26.

[0050] It should be noted that the second sprayer 26 can use a gravity-fed atomizing nozzle distributor. This gravity-fed atomizing nozzle distributor is a liquid distribution device that combines gravity drive and atomization technology. Without the need for external driving force, the liquid passes through the nozzle of the gravity-fed atomizing nozzle distributor to form fine droplets, which are atomized and sprayed downwards uniformly. The nozzle of the gravity-fed atomizing nozzle distributor can include at least one of pressure centrifugal atomizing nozzles, impact nozzles, and porous sintered nozzles. The orifice diameter of the nozzle of the gravity-fed atomizing nozzle distributor can be from 0.5 mm to 3 mm, the spray cone angle of the gravity-fed atomizing nozzle distributor can be from 30° to 120°, the particle size of the atomized liquid droplets of the gravity-fed atomizing nozzle distributor can be from 50 μm to 500 μm, and the atomization pressure required by the gravity-fed atomizing nozzle distributor can be from 0.02 MPa to 0.1 MPa.

[0051] It should be noted that the outlet of the second injector 22 can be equipped with a tubular gas-liquid distributor. The main pipe and branch pipes of the tubular gas-liquid distributor are equipped with upward spray nozzles. The diameter of the nozzles can be 2mm to 10mm. The flow velocity of the second gas-liquid two-phase mixture at the nozzles of the tubular gas-liquid distributor can be 1.0m / s to 8.0m / s.

[0052] It should be noted that a third distributor 131 can be installed in the third reaction section 13, and the third distributor 131 is located above the third contact reaction section. Furthermore, a three-stage primary circulating alkali inlet can be installed in the third reaction section 13, and the three-stage primary circulating alkali inlet is located between the outlet of the third discharge purified gas and the third distributor 131. The three-stage primary circulating alkali solution from the third liquid tank 332 enters the third reaction section 13 through the three-stage primary circulating alkali solution inlet, and shares the third distributor 131 with the three-stage feed alkali solution from the bottom of the second reaction section 12. Within the third distributor 131, the three-stage primary circulating alkali solution and the three-stage feed alkali solution are thoroughly mixed to form a third mixture. The third mixture enters the third contact section 132 from top to bottom and undergoes countercurrent contact with the third discharge purified gas from the third gas tank 333, which enters the third contact section 132 from bottom to top. During this countercurrent contact, the third mixture absorbs some of the hydrogen sulfide in the third discharge purified gas, resulting in reactions including reaction formulas (1) and (2). After absorbing some of the hydrogen sulfide in the third discharge purified gas, the third mixture continues to flow from top to bottom to the bottom of the third reaction section 13, where it is buffered to separate the carried gas, which is then discharged as the third discharge alkali solution. After some of the hydrogen sulfide in the third discharge purified gas is absorbed by the third mixed liquid in the third contact section 132, it can be discharged at the top of the third reaction section 13 and introduced into the receiving chamber of the second injector 22.

[0053] It should be noted that the third contact segment 132 has the same structure, size and type as the first contact segment 112.

[0054] It should be noted that the three-stage alkali solution enters the upper part of the third separation device from the bottom outlet of the third reaction section 13 and is evenly sprayed into the third separation device through the third sprayer 27. The spray velocity can be from 1.0 m / s to 8.0 m / s. At this time, the three-stage alkali solution from the third reaction section 13 is sprayed downward, while the third gas-liquid two-phase mixture from the third sprayer 23 is sprayed upward. The three-stage alkali solution and the third gas-liquid two-phase mixture undergo a series of operations of contact, collision, mixing, heat transfer and mass transfer in the third separation tank 33 of the third separation device, and promote the further reaction of hydrogen sulfide in the third gas-liquid two-phase mixture with sodium-containing alkaline substances (sodium hydroxide and / or sodium sulfide) in the three-stage alkali solution to generate sodium hydrosulfide.

[0055] It should be noted that the third injector 23 consists of four parts: a nozzle, a receiving chamber, a mixing chamber, and a diffusion chamber. The three-stage secondary circulating alkaline solution, pressurized by the third circulation pump 43 in the third separation device, enters the nozzle of the second injector 22. After being sprayed through the nozzle, it generates a high flow velocity. This high-velocity three-stage secondary circulating alkaline solution can create a low-pressure zone around the nozzle, thus drawing the hydrogen sulfide-containing acidic gas from the hydrogen sulfide-containing acidic gas inlet pipe 24 into the receiving chamber. In the receiving chamber, the hydrogen sulfide-containing acidic gas and the three-stage secondary circulating alkaline solution undergo preliminary mixing before entering the mixing chamber, where they are fully mixed to form turbulence. During this process, the three-stage secondary circulating alkaline solution... The cyclic alkaline solution can absorb some of the hydrogen sulfide in the acidic gas containing hydrogen sulfide and undergo reactions including reaction formula (1) and reaction formula (2). Then, the gas-liquid two-phase mixture at the outlet of the mixing chamber can enter the diffusion chamber as a third gas-liquid two-phase mixture. Based on the design of the diffusion chamber with gradually increasing diameter, the flow rate of the third gas-liquid two-phase mixture gradually decreases, and the kinetic energy of the third gas-liquid two-phase mixture is converted into pressure energy, which increases the outlet pressure of the third gas-liquid two-phase mixture in the diffusion chamber. This avoids the use of pressure boosting equipment, simplifies the process flow, and reduces equipment costs and operating expenses. The third injector 23 can quickly complete the reactions including reaction formula (1) and reaction formula (2) within 0.005s to 0.400s, which is beneficial to reduce by-reaction products such as sodium carbonate and sodium bicarbonate in the sodium hydrosulfide product.

[0056] It should be noted that the operating temperature of the third reaction section 13 can be from 45℃ to 75℃, and the operating pressure of the third reaction section 13 is greater than or equal to 5 kPaG; the operating temperature of the third ejector 23 is from 50℃ to 80℃, and the difference between the outlet pressure of the third ejector 23 and the operating pressure of the third separation device can be greater than or equal to 15 kPa. The outlet pressure of the third ejector 23 can also be the sum of the operating pressure of the third separation device and the pipeline pressure drop of the third gas-liquid two-phase mixture from the third ejector 23 to the third separation device. In order to ensure the stable operation of the third ejector 23 and the third separation device, the outlet pressure of the third ejector 23 needs to be maintained at a high value, so as to provide sufficient driving force for the material to flow downstream.

[0057] It should be noted that after the three-stage alkali solution is discharged from the bottom of the third reaction section 13, it enters the upper part of the third separation tank 33 and is evenly sprayed into the lower part of the third separation tank 33 of the third separation device through the third sprayer 27 under the action of gravity. It is set that there is a liquid level difference or height difference between the bottom discharge port of the third reaction section 13 and the feed port of the third separation tank 33. These liquid level differences or height differences can be from 0.2m to 12.0m, which can provide the necessary pressure for atomization of the nozzle of the third sprayer 27.

[0058] It should be noted that the third sprayer 27 can use a gravity-fed atomizing nozzle distributor. This gravity-fed atomizing nozzle distributor is a liquid distribution device that combines gravity drive and atomization technology. Without the need for external driving force, the liquid passes through the nozzle of the gravity-fed atomizing nozzle distributor to form fine droplets, which are atomized and sprayed uniformly downwards. The nozzle of the gravity-fed atomizing nozzle distributor can include at least one of pressure centrifugal atomizing nozzles, impact nozzles, and porous sintered nozzles. The orifice diameter of the nozzle of the gravity-fed atomizing nozzle distributor can be from 0.5 mm to 3 mm, the spray cone angle of the gravity-fed atomizing nozzle distributor can be from 30° to 120°, the particle size of the atomized liquid droplets of the gravity-fed atomizing nozzle distributor can be from 50 μm to 500 μm, and the atomization pressure required by the gravity-fed atomizing nozzle distributor can be from 0.02 MPa to 0.1 MPa.

[0059] It should be noted that the outlet of the third injector 23 can be equipped with a tubular gas-liquid distributor. The main pipe and branch pipes of the tubular gas-liquid distributor are equipped with upward spray nozzles. The diameter of the nozzles can be 2mm to 10mm. The flow velocity of the third gas-liquid two-phase mixture at the nozzles of the tubular gas-liquid distributor can be 1.0m / s to 8.0m / s.

[0060] It should be noted that a stripping zone and a direct steam stripping inlet can be installed at the bottom of the sodium hydrosulfide reaction tower 1. When the concentration of sodium hydrosulfide from the third liquid tank 332 is higher than the required discharge standard, steam can be introduced into the stripping zone through the direct steam stripping inlet. Through direct steam stripping, the sodium hydrosulfide in the third liquid tank 332 comes into countercurrent contact with the upward-flowing steam in the stripping zone. During this countercurrent contact, impurities such as ammonia and oil carried in the sodium hydrosulfide are separated from it through stripping. The steam condenses into condensate due to heat release. This condensate can dilute the sodium hydrosulfide, increasing the overall yield of sodium hydrosulfide while ensuring the product meets the standards, thus improving the overall economic efficiency of the system.

[0061] It should be noted that a reboiling zone and a reboiling stripping feed inlet can also be installed at the bottom of the sodium hydrosulfide reaction tower 1. If the concentration of sodium hydrosulfide from the third liquid tank 332 is lower than the required discharge standard, the sodium hydrosulfide from the third liquid tank 332 can be introduced into the reboiling zone. In the reboiling zone, the sodium hydrosulfide from the third liquid tank 332 will be heated by the heat exchange medium, causing some of the water in the sodium hydrosulfide from the third liquid tank 332 to vaporize due to the heat. The vaporized water will form water vapor, thus concentrating the sodium hydrosulfide in the third liquid tank 332. Ultimately, various specifications of sodium hydrosulfide liquid products can be achieved according to the different degrees of water vaporization in the sodium hydrosulfide, meeting the output requirements of different sodium hydrosulfide products.

[0062] It should be noted that when the tail gas contains ammonia, an ammonia absorption tower can be added at the top of the sodium hydrosulfide reaction tower 1. The tail gas containing ammonia comes into countercurrent contact with demineralized water or deoxygenated water in the ammonia absorption tower, so that the demineralized water or deoxygenated water absorbs the ammonia component in the tail gas and converts it into ammonia water. This ammonia water can then be introduced into an ammonia distillation tower through pipelines for further purification treatment, and finally refined ammonia water that meets the requirements of "Industrial Ammonia Water" (HG / T 5353-2018) can be obtained.

[0063] In some optional embodiments, the spray circulation unit 2 further includes a second injector 22, a second separation device, a second sprayer 26, and a second circulating cooling device. The inlet of the second injector 22 is connected to the upper outlet of the second reaction section 12, and the outlet of the second injector 22 is connected to the inlet of the second separation device. The outlet of the second separation device is connected to the lower inlet of the second reaction section 12 and the inlet of the second circulating cooling device, respectively. The outlet of the second circulating cooling device is connected to the inlet of the second injector 22 and the upper inlet of the second reaction section 12, respectively. The second sprayer 26 is disposed inside the second separation device, and the inlet of the second sprayer 26 is connected to the bottom liquid outlet of the second reaction section 12.

[0064] In these embodiments, a jet circulation unit 2, comprising a second injector 22, a second separation device, a second sprayer 26, and a second circulation cooling device, is used. The second injector 22 thoroughly mixes the third discharge purified gas and the second-stage secondary circulating alkaline solution to form a second gas-liquid two-phase mixture. The second sprayer 26 then allows the second-stage discharge alkaline solution and the second gas-liquid two-phase mixture to undergo a series of operations—contact, collision, mixing, heat transfer, and mass transfer—within the second separation device. This further promotes the reaction between hydrogen sulfide in the second gas-liquid two-phase mixture and sodium-containing alkaline substances (sodium hydroxide and / or sodium sulfide) in the second-stage discharge alkaline solution to generate sodium hydrosulfide, thereby increasing the yield of sodium hydrosulfide. Additionally, the second circulation cooling device removes the heat of reaction and divides the alkaline solution in the second liquid tank 332 into a second-stage primary circulating alkaline solution and a second-stage secondary circulating alkaline solution, achieving multi-stage circulation of the alkaline solution.

[0065] In some optional embodiments, the second separation device includes a second separation tank 32 and a second liquid reservoir 322, a second gas reservoir 323, and a second coalescer 321 disposed within the second separation tank 32. The inlet of the second separation tank 32 is connected to the outlet of the second ejector 22, and the second coalescer 321 is disposed at one end of the second separation tank 32. According to the gas diffusion direction, the second liquid reservoir 322 is disposed downstream of the second coalescer 321. The second gas reservoir 323 is symmetrically disposed with respect to the second liquid reservoir 322. The outlet of the second gas reservoir 323 is connected to the lower inlet of the second reaction section 12, and the outlet of the second liquid reservoir 322 is connected to the second circulating cooling device.

[0066] In these embodiments, a second separation device is used, including a second separation tank 32 and a second liquid reservoir 322, a second gas reservoir 323, and a second coalescer 321 disposed within the second separation tank 32. The second mixed reaction product, including the second-stage effluent alkali solution and the second gas-liquid two-phase mixture, can be separated by the second coalescer 321 to obtain gas and liquid. After the liquid carried by the gas is separated in the second gas reservoir 323, it is returned to the second reaction section 12 for recycling as the second effluent purified gas. The liquid is buffered and separated from the gas in the second liquid reservoir 322. Subsequently, the liquid is used as the second-stage circulating alkali solution. After being processed by the second circulating cooling device, the second-stage circulating alkali solution can be divided into a second-stage primary circulating alkali solution and a second-stage secondary circulating alkali solution.

[0067] It should be noted that the second coalescer 321 can be at least one of corrugated plate, filter cartridge, electrostatic, and packing types. The second coalescer 321 can divide the second separation tank 32 into a reaction side and a separation side. In the reaction side, the second-stage effluent alkaline solution and the second gas-liquid two-phase mixture are mixed, heat-transferred, mass-transferred, and reacted to obtain the second mixed reaction product. The second mixed reaction product passes through the second coalescer 321 from the reaction side and enters the separation side. The second coalescer 321 separates the gas and liquid phases of the second mixed reaction product. After separation by the second coalescer 321, the following two effects can be achieved: Firstly, the liquid content in the gas entering the separation side is ≤0.1mg / m3, and the droplet removal rate is ≥99.9%. Subsequently, this gas enters the second gas tank 323 for further separation of the carried liquid, and then returns to the second reaction section 12 as the second discharge purified gas. Specifically, the return position is below the second contact section 122 and above the highest liquid level at the bottom of the second reaction section 12. Secondly, the gas content in the liquid entering the separation side is ≤1.0mg / kg. This liquid enters the second liquid tank 322 for buffering, and after further separation of the carried gas, it becomes the second-stage circulating alkali solution. This second-stage circulating alkali solution is pressurized by the second circulating pump 42 of the second circulating cooling device and cooled by the second cooler 52, and then split into two parts. One part enters the upper part of the second reaction section 12 as the second-stage primary circulating alkali solution, and the other part enters the second ejector 22 as the second-stage secondary circulating alkali solution.

[0068] In some optional embodiments, the second circulating cooling device includes: a second circulating pump 42 and a second cooler 52, the inlet of the second circulating pump 42 being connected to the outlet of the second liquid tank 322, the outlet of the second circulating pump 42 being connected to the inlet of the second cooler 52, and the outlet of the second cooler 52 being connected to the inlet of the second injector 22 and the upper inlet of the second reaction section 12, respectively.

[0069] In these embodiments, the second circulating cooling device using the second circulating pump 42 and the second cooler 52 can fully pressurize, cool and remove the heat of reaction of the two-stage circulating alkaline solution, and split the two-stage circulating alkaline solution into two-stage primary circulating alkaline solution and two-stage secondary circulating alkaline solution.

[0070] It should be noted that the operating temperature of the second cooler 52 can be between 35°C and 45°C.

[0071] In some optional embodiments, the first separation device includes a first separation tank 31 and a first liquid reservoir 312, a first gas reservoir 313, and a first coalescer 311 disposed within the first separation tank 31. The inlet of the first separation tank 31 is connected to the outlet of the first ejector 21, and the first coalescer 311 is disposed at one end of the first separation tank 31. According to the gas diffusion direction, the first liquid reservoir 312 is disposed downstream of the first coalescer 311, the first gas reservoir 313 is symmetrically disposed with respect to the first liquid reservoir 312, the outlet of the first gas reservoir 313 is connected to the lower inlet of the first reaction section 11, and the outlet of the first liquid reservoir 312 is connected to the first circulating cooling device. The third separation device includes a third separation tank 33 and a third liquid reservoir 332, a third gas reservoir 333, and a third coalescer 331 disposed within the third separation tank 33. The inlet of the third separation tank 33 is connected to the outlet of the third ejector 23. The third coalescer 331 is disposed at one end of the third separation tank 33. In accordance with the gas diffusion direction, the third liquid reservoir 332 is disposed downstream of the third coalescer 331. The third gas reservoir 333 is symmetrically arranged with the third liquid reservoir 332. The outlet of the third gas reservoir 333 is connected to the lower inlet of the third reaction section 13. The outlet of the third liquid reservoir 332 is connected to the third circulating cooling device.

[0072] In these embodiments, a first separation device is used, including a first separation tank 31 and a first liquid reservoir 312, a first gas reservoir 313 and a first coalescer 311 disposed within the first separation tank 31. The first coalescer 311 can separate the first mixed reaction product, which includes a first discharge alkaline solution and a first gas-liquid two-phase mixture, to obtain gas and liquid. After the liquid carried by the gas is separated in the first gas reservoir 313, it is returned to the first reaction section 11 for recycling as the first discharge purified gas. The liquid is buffered and separated from the gas in the first liquid reservoir 312. Subsequently, the liquid is used as a first-stage circulating alkaline solution. After being processed by the first circulating cooling device, the first-stage circulating alkaline solution can be divided into a first-stage circulating alkaline solution and a second-stage circulating alkaline solution. In addition, using a third separation device including a third separation tank 33 and a third liquid tank 332, a third gas tank 333 and a third coalescer 331 disposed within the third separation tank 33, the third mixed reaction product including the three-stage effluent alkali solution and the third gas-liquid two-phase mixture can be separated by the third coalescer 331 to obtain gas and liquid. After the liquid carried by these gases is separated in the third gas tank 333, they are returned to the third reaction section 13 for recycling as the third effluent purified gas. The liquids are buffered and separated from the gas in the third liquid tank 332. Subsequently, these liquids are used as the three-stage circulating alkali solution. After being processed by the third circulating cooling device, the three-stage circulating alkali solution can be divided into three-stage primary circulating alkali solution, three-stage secondary circulating alkali solution and sodium hydrosulfide product.

[0073] It should be noted that the first coalescer 311 can be at least one of corrugated plate, filter cartridge, electrostatic, and packing types. The first coalescer 311 divides the first separation tank 31 into a reaction side and a separation side. In the reaction side, the discharged alkaline solution and the first gas-liquid two-phase mixture undergo mixing, heat transfer, mass transfer, and reaction to obtain the first mixed reaction product. The first mixed reaction product passes through the first coalescer 311 from the reaction side and enters the separation side. The first coalescer 311 separates the gas and liquid phases of the first mixed reaction product. Specifically, in the first coalescer 311, which is composed of a corrugated plate separation section and a filter cartridge separation section, the first mixed reaction product first flows through the corrugated plate separation section. Within the narrow, tortuous flow channel of the corrugated plate separation section, the direction and velocity of the fluid formed by the first mixed reaction product continuously change. The liquid phase in the first mixed reaction product is thrown towards the corrugated plate surface under the action of inertial centrifugal force, achieving preliminary gas-liquid separation through coalescence, merging, and sedimentation. Subsequently, the product enters the filter separation section, where the tiny droplets carried in the gas phase are captured on the fiber surface and aggregate to increase in size thanks to multiple mechanisms, including fiber interception, inertial collision, and Brownian motion in the coalescing layer. Finally, after gravity and drag force overcome the adhesion between the droplets and fibers, the droplets are effectively separated from the gas phase.

[0074] After separation by the first coalescer 311, the following two effects can be achieved: Firstly, the liquid content in the gas entering the separation side is ≤0.1mg / m³. 3 The droplet removal rate is ≥99.9%. Subsequently, these gases enter the first gas tank 313 for further separation of the carried liquid, and then return to the second reaction section 12 as the first discharge purified gas. Specifically, the return position is below the first contact section 112 and above the highest liquid level at the bottom of the first reaction section 11. On the other hand, the liquid entering the separation side contains ≤1.0mg / kg of gas. This liquid enters the first liquid tank 312 for buffering, and after further separation of the carried gas, it becomes a first-stage circulating alkali solution. This first-stage circulating alkali solution is pressurized by the first circulating pump 41 of the first circulating cooling device and cooled by the first cooler 51, and then split into two parts. One part enters the upper part of the first reaction section 11 as a first-stage circulating alkali solution, and the other part enters the first ejector 22 as a second-stage circulating alkali solution.

[0075] It should be noted that the third coalescer 331 can use at least one of the following: corrugated plate, filter cartridge, electrostatic, and packed type. The third coalescer 331 divides the third separator 33 into a reaction side and a separation side. On the reaction side, the three-stage effluent alkaline solution and the third gas-liquid two-phase mixture undergo mixing, heat transfer, mass transfer, and reaction to obtain the third mixed reaction product. The third mixed reaction product passes through the third coalescer 331 from the reaction side and enters the separation side. The third coalescer 331 separates the gas and liquid phases of the third mixed reaction product. Similar to the first coalescer 311, after separation by the third coalescer 331, the following two effects can be achieved: Firstly, the liquid content in the gas entering the separation side is ≤0.1 mg / m³. 3 The droplet removal rate is ≥99.9%. Subsequently, these gases enter the third gas tank 333 for further separation of the carried liquid, and then return to the third reaction section 13 as the third discharge purified gas. Specifically, the return position is below the third contact section 132 and above the highest liquid level at the bottom of the third reaction section 13. On the other hand, the liquid entering the separation side has a gas content ≤1.0mg / kg. These liquids enter the third liquid tank 332 for buffering, and after further separation of the carried gas, they become the three-stage circulating alkaline solution. After being pressurized by the third circulating pump 43 of the third circulating cooling device and cooled by the third cooler 53, the three-stage circulating alkaline solution is split into two parts. One part enters the upper part of the third reaction section 13 as the third-stage primary circulating alkaline solution, and the other part enters the third ejector 23 as the third-stage secondary circulating alkaline solution.

[0076] In some optional embodiments, the first circulating cooling device includes a first circulating pump 41 and a first cooler 51. The inlet of the first circulating pump 41 is connected to the outlet of the first liquid tank 312, the outlet of the first circulating pump 41 is connected to the inlet of the first cooler 51, and the outlet of the first cooler 51 is connected to the inlet of the first injector 21 and the upper inlet of the first reaction section 11, respectively. The third circulating cooling device includes a third circulating pump 43 and a third cooler 53. The inlet of the third circulating pump 43 is connected to the outlet of the third liquid package 332, and the outlet of the third circulating pump 43 is connected to the inlet of the third cooler 53. The outlet of the third cooler 53 is connected to the inlet of the third injector 23 and the upper inlet of the third reaction section 13, respectively.

[0077] In these embodiments, the first circulating cooling device, using the first circulating pump 41 and the first cooler 51, can sufficiently pressurize, cool, and remove the heat of reaction from a section of circulating alkali solution, and separate the section of circulating alkali solution into a primary circulating alkali solution and a secondary circulating alkali solution. Furthermore, the third circulating cooling device, using the third circulating pump 43 and the third cooler 53, can sufficiently pressurize, cool, and remove the heat of reaction from three sections of circulating alkali solution, and separate the three sections of circulating alkali solution into three primary circulating alkali solutions, three secondary circulating alkali solutions, and sodium hydrosulfide product.

[0078] It should be noted that the operating temperature of the first cooler 51 can be between 35°C and 45°C. The operating temperature of the third cooler 53 can be between 35°C and 45°C.

[0079] In some optional embodiments, the sodium hydrosulfide reaction unit further includes: a first downcomer 114 and a second downcomer 124, wherein the first downcomer 114 penetrates the first isolation member 113, and a gas-blocking sealing plate is provided at the bottom end of the first downcomer 114 to isolate gas exchange between the first reaction section 11 and the second reaction section 12; the second downcomer 124 penetrates the second isolation chamber, and a gas-blocking sealing plate is provided at the bottom end of the second downcomer 124 to isolate gas exchange between the second reaction section 12 and the third reaction section 13.

[0080] In these embodiments, a first downcomer 114 and a second downcomer 124 are provided within the sodium hydrosulfide reaction unit. The first downcomer 114 connects the first reaction section 11 and the second reaction section 12, and the second downcomer 124 connects the second reaction section 12 and the third reaction section 13. This allows various alkaline solutions to fully contact and react with various hydrogen sulfide-containing gases in different reaction sections, thereby increasing the yield of sodium hydrosulfide. Furthermore, gas-blocking sealing plates are provided at the bottom of the first downcomer 114 and the second downcomer 124 to prevent gas exchange between the first reaction section 11, the second reaction section 12, and the third reaction section 13. This improves the reaction efficiency of each stage and ensures the yield and purity of the sodium hydrosulfide product.

[0081] In some optional embodiments, the formula for calculating the diameter of the first downcomer 114 or the second downcomer 124 is: Equation 1; A=0.785D 2 Equation 2; In Equation 1, f is the coefficient of friction; when D ≤ 0.015m, f is 0.027; when D ≥ 0.100m, f is 0.017; when 0.015m < D < 0.100m, f satisfies the following: Equation 3; In Equations 1, 2, and 3, Q represents the liquid volumetric flow rate through the first downcomer 114 or the second downcomer 124, in m³ / s. 3 / s;C d , where is the flow coefficient, with a value of 0.65; A is the cross-sectional area of ​​the first downcomer 114 or the second downcomer 124, in meters. 2 h represents the vertical height difference between the first downcomer 114 and the second downcomer 124, in meters; g represents the acceleration due to gravity, with a value of 9.81 m / s². 2 D is the diameter of the first downcomer 114 or the second downcomer 124, in meters; L is the length of the first downcomer 114 or the second downcomer 124, in meters.

[0082] In these embodiments, the diameters of the first downcomer 114 and the second downcomer 124 need to be determined by trial and error. This calculation is mainly based on key parameters such as liquid volumetric flow rate, flow coefficient, and vertical height difference, and is performed by combining Equations 1, 2, and 3 to ensure that the second and third stage feed alkaline solutions can flow smoothly downwards by gravity.

[0083] It should be noted that the length of the first downcomer 114 or the second downcomer 124 can be numerically equal to the difference in vertical height between the first downcomer 114 and the second downcomer 124.

[0084] In some optional embodiments, the sodium hydrosulfide reaction unit further includes: a first distributor 111, a second distributor 121, and a third distributor 131, wherein the first distributor 111 is disposed between the sodium-containing alkali inlet pipe 14 and the first contact section 112; the second distributor 121 is disposed above the second contact section 122; and the third distributor 131 is disposed between the upper feed inlet of the third reaction section 13 and the third contact section 132.

[0085] In these embodiments, a first distributor 111, a second distributor 121, and a third distributor 131 are introduced into the sodium hydrosulfide reaction unit. These distributors can uniformly disperse the sodium-containing alkaline solution and the first-stage circulating alkaline solution in the first reaction section 11, the second-stage feed alkaline solution and the second-stage circulating alkaline solution in the second reaction section 12, and the third-stage feed alkaline solution and the third-stage circulating alkaline solution in the third reaction section 13. Then, they react fully with the first discharge purified gas in the first reaction section 11, the second discharge purified gas in the second reaction section 12, and the second discharge purified gas in the third reaction section 13, thereby improving the yield and purity of the final sodium hydrosulfide product.

[0086] It should be noted that the first distributor 111, the second distributor 121 and the third distributor 131 can all be at least one of the following: single-stage trough distributor, multi-stage trough distributor, sieve disc distributor, jet distributor and tubular distributor.

[0087] It should be noted that the first distributor 111, the second distributor 121 and the third distributor 131 can all be provided with a gas phase channel for upward gas flow. The gas phase channel can be a cylindrical riser pipe with a diameter of 50mm to 150mm. A rain cap can be provided at the top of each cylindrical riser pipe, and multiple cylindrical risers are evenly arranged in the corresponding distributor.

[0088] In summary, the embodiments of this application provide a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas. This system achieves efficient absorption and deep purification of exhaust gas through multi-stage countercurrent absorption, multi-stage injection circulation, secondary spraying within the separation device, and optimized anti-gas-crossing structure design. While meeting environmental emission standards, it maximizes the yield and purity of sodium hydrosulfide products. 1. Three-stage countercurrent absorption: gradient reduction of hydrogen sulfide concentration The sodium hydrosulfide reaction tower 1 is divided into three reaction sections in series by the first isolation element 113 and the second isolation element 123: the third reaction section 13, the second reaction section 12, and the first reaction section 11. The hydrogen sulfide-containing acidic gas first enters the system from the third injector 23 and comes into countercurrent contact with the sodium-containing alkaline solution flowing from top to bottom in the sodium hydrosulfide reaction tower 1, forming a gradient absorption system of "preferential treatment of high-concentration gas and deep purification of low-concentration gas". (1) Third reaction section 13 (primary absorption): After the hydrogen sulfide-containing acidic gas is pressurized by the third injector 23, it reacts with the three-stage feed alkaline solution and the three-stage primary circulating alkaline solution evenly distributed by the third distributor 131 in the third contact section 132. Most of the hydrogen sulfide is absorbed and sodium hydrosulfide is generated.

[0089] (2) Second reaction section 12 (intermediate absorption): The incompletely absorbed hydrogen sulfide-containing acidic gas forms the third discharge purified gas. After being pressurized by the second injector 22 and separated by the second separator 32, it reacts again with the alkaline solution sprayed by the second distributor 121 in the second contact section 122 to further reduce the hydrogen sulfide concentration. The system includes the second injector 22. After the third discharge purified gas is mixed and reacted by the second injector 22, it enters the second separator 32 to react again and undergo gas-liquid separation. The separated gas is returned to the second reaction section 12 as the second discharge purified gas, thus extending the reaction path.

[0090] (3) First reaction section 11 (deep purification): The first discharged purified gas from the first separator 31 reacts deeply with the fresh, high-concentration sodium-containing alkaline solution introduced through the sodium-containing alkaline solution inlet pipe 14 in the first contact section 112, ensuring that the hydrogen sulfide content in the tail gas is reduced to an extremely low level. The liquid droplets carried by the first discharged purified gas are intercepted by the gas-liquid separator 115 at the top of the sodium hydrosulfide reaction tower 1 to prevent liquid from escaping and improve reaction efficiency.

[0091] 2. Multi-stage injection cycle: forced circulation and secondary treatment The injection circulation unit 2 achieves multiple circulation treatments of hydrogen sulfide-containing gas through a closed-loop process of injection pressurization, gas-liquid separation, and circulation cooling. (1) The third injector 23 enhances primary absorption: The hydrogen sulfide-containing acidic gas and the bottom three-stage alkali solution of the third reaction section 13 are mixed in the third injector 23 to form a high-speed jet of the third gas-liquid two-phase mixture. At this time, the gas in the third gas-liquid mixture is broken into micron-sized bubbles, which significantly increases the gas-liquid contact area and improves the solubility of hydrogen sulfide in the hydrogen sulfide-containing acidic gas in the three-stage primary circulating alkali solution. The mixed third gas-liquid two-phase mixture enters the third separation device. The separated gas is returned to the bottom of the third reaction section 13 as the third discharge purified gas for continued absorption. The liquid is pressurized and cooled by the third circulating cooling device. Part of it is returned to the third injector 23 for circulation as the third-stage secondary circulating alkali solution, and the other part is sent to the top of the third reaction section 13 for circulation as the third-stage primary circulating alkali solution.

[0092] (2) Second injector 22 optimizes intermediate absorption: The system includes a second injector 22. The third discharge gas from the upper part of the third reaction section 13 is mixed and reacted by the second injector 22, and then enters the second separator 32 to react again and perform gas-liquid separation. The separated gas is returned to the second reaction section 12 as the second discharge purified gas, forming a composite absorption mode of gas-liquid countercurrent and jet circulation, which further reduces the hydrogen sulfide concentration.

[0093] (3) Deep treatment of tail gas by the first injector 21: The unabsorbed second discharge purified gas in the upper part of the second reaction section 12 is mixed and reacted by the first injector 21, and then enters the first separator 31 to react again and perform gas-liquid separation. The separated gas is returned to the second reaction section 11 as the first discharge purified gas for secondary absorption. The first circulating cooling device pressurizes and cools the circulating alkali solution, further improving the efficiency of alkali solution in absorbing hydrogen sulfide.

[0094] 3. Secondary spraying inside the separation unit: intercepting escaped gas. The first and third separation devices are equipped with a first sprayer 25 and a third sprayer 27, respectively, to perform a secondary spraying of the separated hydrogen sulfide-containing gas using circulating alkaline solution, forming a multi-stage local cycle of separation-spraying-reabsorption. (1) Spraying inside the third separation device: The third sprayer 27 can make the three-stage effluent alkaline solution containing high concentration of sodium hydrosulfide come into countercurrent contact with the third gas-liquid two-phase mixture. The unreacted hydrogen sulfide in the third gas-liquid two-phase mixture is absorbed again, and the sodium hydroxide and / or sodium sulfide in the three-stage effluent alkaline solution are further converted into sodium hydrosulfide.

[0095] (2) Spraying inside the first separation device: The first sprayer 25 brings the first batch of alkali solution (containing a high concentration of alkali solution) into countercurrent contact with the first gas-liquid two-phase mixture to further remove residual hydrogen sulfide and ensure that the hydrogen sulfide concentration in the first batch of purified gas entering the first reaction section 11 is lower.

[0096] 4. Optimized anti-gas cross-flow structure: Ensures strict gas classification and treatment. The system completely isolates gas cross-flow between adjacent reaction sections through the design of the gas-blocking sealing plate at the bottom of the downcomer, the first isolation element 113, and the second isolation element 123. (1) Liquid seal of downcomer: Gas blocking sealing plate is provided at the bottom of the first downcomer 114 and the second downcomer 124. These gas blocking sealing plates can form a liquid seal, which is used to prevent gas in the second reaction section 12 from entering the first reaction section 11 and gas in the third reaction section 13 from entering the second reaction section 12, respectively, to ensure that the gas is purified step by step according to the set processing path.

[0097] (2) Enhanced zoning by isolation components: The first isolation component 113 and the second isolation component 123 divide the sodium hydrosulfide reaction tower 1 into three independent reaction sections. Combined with the uniform liquid distribution of the distributors in different reaction sections, the gas-liquid contact in each reaction section is more sufficient, and gas short circuit is avoided.

[0098] 5. Key parameter optimization: improving mass transfer efficiency (1) Calculation of downcomer diameter: Combined with flow parameters such as friction coefficient f and flow coefficient, the dimensions of the first downcomer 114 and the second downcomer 124 are precisely designed to ensure that the liquid flow rate matches the gas processing capacity and avoid flooding or mist entrainment.

[0099] (2) Circulating cooling temperature control: The first, second and third circulating cooling devices control the temperature of various circulating alkaline solutions within the range of 35°C to 45°C, which is used to remove the heat of reaction, control the temperature of each stage of reaction, reduce the vapor pressure of hydrogen sulfide, and increase its solubility in alkaline solutions.

[0100] In summary, the embodiments of this application provide a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas. Through process route reconstruction and equipment structure innovation, this system achieves efficient absorption of hydrogen sulfide-containing acidic gas and deep purification of tail gas, meeting environmental emission standards while maximizing the yield of sodium hydrosulfide products, resulting in significant economic and social benefits.

[0101] Figure 2 An exemplary schematic diagram of a method for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas is shown in an embodiment of this application. Figure 3 for Figure 2 The continuation; Based on a general inventive concept, such as Figure 2 and Figure 3 As shown, this application provides a method for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas. The method is adapted to the system and includes: S1. Divide the sodium-containing alkaline solution into three parts: a first-stage sodium-containing alkaline solution, a second-stage sodium-containing alkaline solution, and a third-stage sodium-containing alkaline solution. S2. A portion of the three sections containing sodium-containing alkaline solution and hydrogen sulfide-containing acidic gas are mixed by a third injection to obtain a third gas-liquid two-phase mixture; S3. The third gas-liquid two-phase mixture and a portion of the three-stage sodium-containing alkaline solution are subjected to a third countercurrent contact reaction to obtain a third mixed reaction product; S4. The third mixed reaction product is subjected to a third coalescence separation to obtain a third discharged purified gas and a three-stage circulating alkaline solution; S5. The three-stage circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a three-stage primary circulating alkaline solution, a three-stage secondary circulating alkaline solution, and sodium hydrosulfide product; wherein, the three-stage secondary circulating alkaline solution is returned to the third spray mixing process as a supplementary material for the three-stage sodium-containing alkaline solution; S6. The three-stage primary circulating alkaline solution and the remaining three-stage sodium-containing alkaline solution are used to perform a third gas-liquid contact reaction with the third effluent purified gas to obtain three-stage effluent alkaline solution and third effluent purified gas; wherein, the three-stage effluent alkaline solution is returned to the third countercurrent contact reaction as a supplement to the three-stage sodium-containing alkaline solution. S7. The third discharged purified gas and part of the second-stage sodium-containing alkaline solution are mixed by a second injection to obtain a second gas-liquid two-phase mixture; S8. The second gas-liquid two-phase mixture and a portion of the second-stage sodium-containing alkaline solution are subjected to a second countercurrent contact reaction to obtain a second mixed reaction product; S9. The second mixed reaction product is subjected to a second coalescence separation to obtain a second discharge purified gas and a second-stage circulating alkaline solution; S10. The two-stage circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a two-stage primary circulating alkaline solution and a two-stage secondary circulating alkaline solution; wherein, the two-stage secondary circulating alkaline solution is returned to the second spray mixing as a supplementary material for the two-stage sodium-containing alkaline solution; S11. Using the second-stage primary circulating alkaline solution and the remaining second-stage sodium-containing alkaline solution, the second effluent purified gas undergoes a second gas-liquid contact reaction to obtain a second-stage effluent alkaline solution, a third-stage feed alkaline solution, and a second effluent purified gas; wherein, the third-stage feed alkaline solution is mixed with the third-stage primary circulating alkaline solution and returned to the third gas-liquid contact reaction as the third-stage primary circulating alkaline solution; a portion of the second-stage effluent alkaline solution is returned to the second countercurrent contact reaction as a supplement to the second-stage sodium-containing alkaline solution; and the remaining second-stage effluent alkaline solution is used as a supplement to the third-stage sodium-containing alkaline solution. S12. The second discharged purified gas and a portion of the sodium-containing alkaline solution are mixed by a first injection to obtain a first gas-liquid two-phase mixture; S13. The first gas-liquid two-phase mixture and a portion of the sodium-containing alkaline solution are subjected to a first countercurrent contact reaction to obtain a first mixed reaction product; S14. The first mixed reaction product is subjected to a first coalescence separation to obtain a first discharge purified gas and a first-stage circulating alkaline solution; S15. The first-stage circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a first-stage circulating alkaline solution and a second-stage circulating alkaline solution; wherein, the second-stage circulating alkaline solution is returned to the first spray mixing process as a supplementary material for the first-stage sodium-containing alkaline solution; S16. Using the first-stage circulating alkali solution and the remaining first-stage sodium-containing alkali solution, the first-discharge purified gas undergoes a first gas-liquid contact reaction to obtain a first-stage discharge alkali solution, a second-stage feed alkali solution, and tail gas; wherein, the second-stage feed alkali solution is mixed with the second-stage first-stage circulating alkali solution and returned to the second gas-liquid contact reaction as the second-stage first-stage circulating alkali solution; a portion of the first-stage discharge alkali solution is returned to the first countercurrent contact reaction as a supplement to the first-stage sodium-containing alkali solution; and the remaining first-stage discharge alkali solution is used as a supplement to the second-stage sodium-containing alkali solution.

[0102] This method is based on the system described above. The specific structure of the system can be referred to in the above embodiments. Since this method adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0103] It should be noted that the third injection mixing, the second injection mixing, and the first injection mixing do not refer to the order of injection mixing, but rather correspond to the working processes of different injectors in the system provided in the embodiments of this application. Similarly, the third countercurrent contact reaction, the second countercurrent contact reaction, and the first countercurrent contact reaction do not refer to the order of countercurrent contact reactions, but rather correspond to the working processes of the separation tanks in different separation devices in the system provided in the embodiments of this application. Similarly, the third coalescing separation, the second coalescing separation, and the first coalescing separation do not refer to the operational order of coalescing separation, but rather correspond to the working processes of the coalescers in different separation devices in the system provided in the embodiments of this application. Similarly, the third gas-liquid contact reaction, the second gas-liquid contact reaction, and the first gas-liquid contact reaction do not refer to the operational order of gas-liquid contact reactions, but rather correspond to the working processes of the coalescers in different gas-liquid contact sections in the system provided in the embodiments of this application.

[0104] In some optional embodiments, the temperatures of the first, second, and third injection mixtures are 50°C to 80°C, the times of the first, second, and third injection mixtures are 0.005s to 0.400s, and the pressures of the first, second, and third injection mixtures are greater than or equal to 25kPa.

[0105] In these embodiments, the first, second, and third injection mixing processes, with temperatures ranging from 50°C to 80°C, times ranging from 0.005s to 0.400s, and pressures greater than or equal to 25kPa, can ensure thorough mixing between the first-stage secondary circulating alkaline solution and the second-discharge purified gas, the second-stage secondary circulating alkaline solution and the third-discharge purified gas, and the third-stage secondary circulating alkaline solution and the hydrogen sulfide-containing acidic gas, respectively, to form the first, second, and third gas-liquid two-phase mixtures, which is beneficial for the subsequent first, second, and third countercurrent contact reactions.

[0106] The temperatures of the first, second, and third spray mixtures can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C.

[0107] The mixing times for the first, second, and third injections can be 0.005s, 0.010s, 0.015s, 0.020s, 0.030s, 0.040s, 0.050s, 0.100s, 0.150s, 0.200s, 0.250s, 0.300s, 0.350s, or 0.400s.

[0108] In some optional embodiments, the temperatures of the first gas-liquid contact reaction, the second gas-liquid contact reaction, and the third gas-liquid contact reaction are 45°C to 75°C, respectively; and the pressures of the first gas-liquid contact reaction, the second gas-liquid contact reaction, and the third gas-liquid contact reaction are each greater than or equal to 5 kPa.

[0109] In these embodiments, the first gas-liquid contact reaction, the second gas-liquid contact reaction, and the third gas-liquid contact reaction at temperatures of 45°C to 75°C and pressures of 5 kPa and above, respectively, allow for sufficient reaction between various alkaline solutions and various hydrogen sulfide-containing gases in the gas-liquid contact reaction, thereby effectively reducing the hydrogen sulfide content in the exhaust gas and increasing the yield of sodium hydrosulfide products.

[0110] The temperatures for the first gas-liquid contact reaction, the second gas-liquid contact reaction, and the third gas-liquid contact reaction can be 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, or 75℃, respectively.

[0111] In some optional embodiments, the flow rate of the three-stage primary circulating alkaline solution is 0.5 to 6.0 times the flow rate of the sodium-containing alkaline solution, and the flow rate of the three-stage secondary circulating alkaline solution is 1.5 to 15.0 times the flow rate of the sodium-containing alkaline solution; and / or The flow rate of the primary circulating alkaline solution in the second stage is 0.5 to 6.0 times the flow rate of the sodium-containing alkaline solution, and the flow rate of the secondary circulating alkaline solution in the second stage is 1.5 to 15.0 times the flow rate of the sodium-containing alkaline solution; and / or The flow rate of the first-stage circulating alkaline solution is 0.5 to 6.0 times that of the sodium-containing alkaline solution, and the flow rate of the second-stage circulating alkaline solution is 1.5 to 15.0 times that of the sodium-containing alkaline solution.

[0112] In these embodiments, a three-stage primary circulating alkaline solution with a flow rate of 0.5 to 6.0 times that of the sodium-containing alkaline solution and a three-stage secondary circulating alkaline solution with a flow rate of 1.5 to 15.0 times that of the sodium-containing alkaline solution can facilitate the rapid reaction of various alkaline solutions and hydrogen sulfide-containing gases in the third reaction stage 13 and the third separation unit, thereby reducing the generation of side reactions and increasing the yield of sodium hydrosulfide product. Furthermore, a two-stage primary circulating alkaline solution with a flow rate of 0.5 to 6.0 times that of the sodium-containing alkaline solution and a two-stage secondary circulating alkaline solution with a flow rate of 1.5 to 15.0 times that of the sodium-containing alkaline solution can facilitate the rapid reaction of various alkaline solutions and hydrogen sulfide-containing gases in the second reaction stage 12 and the second separation unit, thereby reducing the generation of side reactions and increasing the yield of sodium hydrosulfide product. In addition, a primary circulating alkaline solution with a flow rate of 0.5 to 6.0 times that of the sodium-containing alkaline solution and a secondary circulating alkaline solution with a flow rate of 1.5 to 15.0 times that of the sodium-containing alkaline solution can facilitate the rapid reaction of various alkaline solutions and hydrogen sulfide-containing gases in the first reaction section 11 and the first separation device, thereby reducing the generation of side reactions and increasing the yield of sodium hydrosulfide products.

[0113] The flow rate of the three-stage primary circulating alkaline solution can be 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, or 6.0 times that of the sodium-containing alkaline solution.

[0114] The flow rate of the three-stage secondary circulating alkaline solution can be 1.5 times, 2.0 times, 2.5 times, 3.0 times, 3.5 times, 4.0 times, 4.5 times, 5.0 times, 10 times, or 15 times the flow rate of the sodium-containing alkaline solution.

[0115] The flow rate of the primary circulating alkaline solution in the second stage can be 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, or 6.0 times that of the sodium-containing alkaline solution.

[0116] The flow rate of the secondary circulating alkaline solution in the two stages can be 1.5 times, 2.0 times, 2.5 times, 3.0 times, 3.5 times, 4.0 times, 4.5 times, 5.0 times, 10 times, or 15 times that of the sodium-containing alkaline solution.

[0117] The flow rate of the primary circulating alkaline solution in this stage can be 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, or 6.0 times that of the sodium-containing alkaline solution.

[0118] The flow rate of the secondary circulating alkaline solution in this stage can be 1.5 times, 2.0 times, 2.5 times, 3.0 times, 3.5 times, 4.0 times, 4.5 times, 5.0 times, 10 times, or 15 times the flow rate of the sodium-containing alkaline solution.

[0119] In some optional embodiments, the flow rates of the gas-liquid two-phase mixture in the first countercurrent contact reaction, the second countercurrent contact reaction, and the third countercurrent contact reaction are 1.0 m / s to 8.0 m / s, respectively, and the durations of the first countercurrent contact reaction, the second countercurrent contact reaction, and the third countercurrent contact reaction are 0.5 s to 15 s, respectively.

[0120] In these embodiments, the first, second, and third countercurrent contact reactions with flow velocities of 1.0 m / s to 8.0 m / s and durations of 0.5 s to 15 s can promote sufficient contact reaction between the gas-liquid two-phase mixtures in different separation devices and the effluent alkaline solution from different reaction sections, effectively reducing the hydrogen sulfide content of different gas-liquid two-phase mixtures and increasing the yield of the final sodium hydrosulfide product.

[0121] The flow velocities of the gas-liquid two-phase mixture in the first countercurrent contact reaction, the second countercurrent contact reaction, and the third countercurrent contact reaction can be 1.0 m / s, 2.0 m / s, 3.0 m / s, 4.0 m / s, 5.0 m / s, 6.0 m / s, 7.0 m / s, or 8.0 m / s, respectively.

[0122] The times for the first countercurrent contact reaction, the second countercurrent contact reaction, and the third countercurrent contact reaction can be 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1.0s, or 1.5s, respectively.

[0123] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0124] Example 1 like Figure 1 As shown, a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas is provided. The system includes: The sodium hydrosulfide reaction unit includes a sodium hydrosulfide reaction tower 1, a first isolation element 113, a second isolation element 123, a gas-liquid separator 115, and a sodium-containing alkali solution inlet pipe 14. The first isolation element 113 and the second isolation element 123 are disposed inside the sodium hydrosulfide reaction tower 1, dividing the sodium hydrosulfide reaction tower 1 into a first reaction section 11, a second reaction section 12, and a third reaction section 13. A first contact section 112 is disposed in the first reaction section 11, a second contact section 122 is disposed in the second reaction section 12, and a third contact section 132 is disposed in the third reaction section 13. The gas-liquid separator 115 is fixedly connected to the top of the sodium hydrosulfide reaction tower 1. The outlet of the sodium-containing alkali solution inlet pipe 14 is connected to the upper part of the sodium hydrosulfide reaction tower 1, and the outlet of the sodium-containing alkali solution inlet pipe 14 is disposed between the first distributor 111 and the gas-liquid separator 115. The injection circulation unit 2 includes a hydrogen sulfide acid gas inlet pipe 24, a first injector 21, a first separation device, a first sprayer 25, a first circulating cooling device, a third injector 23, a third separation device, a third sprayer 27, and a third circulating cooling device. The outlet of the hydrogen sulfide acid gas inlet pipe 24 is connected to the inlet of the third injector 23. The outlet of the third injector 23 is connected to the inlet of the third separation device. The bottom liquid outlet of the sodium hydrosulfide reaction tower 1 is connected to the liquid outlet of the third separation device. The outlet of the third separation device is connected to the lower inlet of the third reaction section 13 and the inlet of the third circulating cooling device. The outlet of the third circulating cooling device is connected to the inlet of the third injector 23 and the upper inlet of the third reaction section 13. The third sprayer 27 is located inside the third separation device. The inlet of the third sprayer 27 is connected to the bottom liquid outlet of the sodium hydrosulfide reaction tower 1. The inlet of the first injector 21 is connected to the upper outlet of the second reaction section 12, the outlet of the first injector 21 is connected to the inlet of the first separation device, the outlet of the first separation device is connected to the lower inlet of the first reaction section 11 and the inlet of the first circulating cooling device, the outlet of the first circulating cooling device is connected to the inlet of the first injector 21 and the upper inlet of the first reaction section 11, the upper inlet of the first reaction section 11 is symmetrically arranged with the sodium-containing alkaline solution inlet pipe 14, the first sprayer 25 is arranged in the first separation device, and the inlet of the first sprayer 25 is connected to the liquid outlet of the first reaction section 11. Sodium hydrosulfide discharge pipe 6, the inlet of sodium hydrosulfide discharge pipe 6 is connected to the outlet of the first circulating cooling device.

[0125] The spray circulation unit 2 also includes a second injector 22, a second separation device, a second sprayer 26, and a second circulation cooling device. The inlet of the second injector 22 is connected to the upper outlet of the third reaction section 13, and the outlet of the second injector 22 is connected to the inlet of the second separation device. The outlet of the second separation device is connected to the lower inlet of the second reaction section 12 and the inlet of the second circulation cooling device. The outlet of the second circulation cooling device is connected to the inlet of the second injector 22 and the upper inlet of the second reaction section 12. The second sprayer 26 is disposed in the second separation device, and the inlet of the second sprayer 26 is connected to the bottom liquid outlet of the second reaction section 12.

[0126] The second separation device includes a second separation tank 32 and a second liquid reservoir 322, a second gas reservoir 323, and a second coalescer 321 disposed within the second separation tank 32. The inlet of the second separation tank 32 is connected to the outlet of the second ejector 22, and the second coalescer 321 is disposed at one end of the second separation tank 32. The second liquid reservoir 322 is disposed downstream of the second coalescer 321 in accordance with the gas diffusion direction. The second gas reservoir 323 is disposed symmetrically with respect to the second liquid reservoir 322. The outlet of the second gas reservoir 323 is connected to the lower inlet of the second reaction section 12, and the outlet of the second liquid reservoir 322 is connected to the second circulating cooling device.

[0127] The second circulating cooling device includes: a second circulating pump 42 and a second cooler 52. The inlet of the second circulating pump 42 is connected to the outlet of the second liquid tank 322, and the outlet of the second circulating pump 42 is connected to the inlet of the second cooler 52. The outlet of the second cooler 52 is connected to the inlet of the second injector 22 and the upper inlet of the second reaction section 12.

[0128] The first separation device includes a first separation tank 31 and a first liquid reservoir 312, a first gas reservoir 313, and a first coalescer 311 disposed within the first separation tank 31. The inlet of the first separation tank 31 is connected to the outlet of the first ejector 21, and the first coalescer 311 is disposed at one end of the first separation tank 31. According to the gas diffusion direction, the first liquid reservoir 312 is disposed downstream of the first coalescer 311, and the first gas reservoir 313 is symmetrically disposed with respect to the first liquid reservoir 312. The outlet of the first gas reservoir 313 is connected to the lower inlet of the first reaction section 11, and the outlet of the first liquid reservoir 312 is connected to the second circulating cooling device. The third separation device includes a third separation tank 33 and a third liquid reservoir 332, a third gas reservoir 333, and a third coalescer 331 disposed within the third separation tank 33. The inlet of the third separation tank 33 is connected to the outlet of the third ejector 23, and the third coalescer 331 is disposed at one end of the third separation tank 33. The third liquid reservoir 332 is disposed downstream of the third coalescer 331 in accordance with the gas diffusion direction. The third gas reservoir 333 is symmetrically disposed with respect to the third liquid reservoir 332. The outlet of the third gas reservoir 333 is connected to the lower inlet of the third reaction section 13, and the outlet of the third liquid reservoir 332 is connected to the second circulating cooling device.

[0129] The first circulating cooling device includes a first circulating pump 41 and a first cooler 51. The inlet of the first circulating pump 41 is connected to the outlet of the first liquid tank 312, and the outlet of the first circulating pump 41 is connected to the inlet of the first cooler 51. The outlet of the first cooler 51 is connected to the inlet of the first injector 21 and the upper inlet of the first reaction section 11, respectively. The third circulating cooling device includes a third circulating pump 43 and a third cooler 53. The inlet of the third circulating pump 43 is connected to the outlet of the third liquid tank 332, and the outlet of the third circulating pump 43 is connected to the inlet of the third cooler 53. The outlet of the third cooler 53 is connected to the inlet of the third injector 23 and the upper inlet of the third reaction section 13, respectively.

[0130] The sodium hydrosulfide reaction unit further includes: a first downcomer 114 and a second downcomer 124. The first downcomer 114 penetrates the first isolation member 113, and a gas-blocking sealing plate is provided at the bottom end of the first downcomer 114 to isolate the gas exchange between the first reaction section 11 and the second reaction section 12. The second downcomer 124 penetrates the second isolation chamber, and a gas-blocking sealing plate is provided at the bottom end of the second downcomer 124 to isolate the gas exchange between the second reaction section 12 and the third reaction section 13.

[0131] The formula for calculating the diameter of the first downcomer 114 or the second downcomer 124 is: Equation 1; A=0.785D 2 Equation 2; In Equation 1, f is the coefficient of friction; when D ≤ 0.015m, f is 0.027; when D ≥ 0.100m, f is 0.017; when 0.015m < D < 0.100m, f satisfies the following: Equation 3; Q is the liquid volume flow rate through the first downcomer 114 or the second downcomer 124, which is 0.0009 m³ / s. 3 / s, C dThe value is 0.65, and h and L are both 0.25m. The diameter (inner diameter) of the first downcomer 114 or the second downcomer calculated and rounded according to Equations 1, 2 and 3 is 0.03m.

[0132] The sodium hydrosulfide reaction unit also includes: a first distributor 111, a second distributor 121 and a third distributor 131. The first distributor 111 is disposed between the sodium-containing alkali inlet pipe 14 and the first contact section 112; the second distributor 121 is disposed above the second contact section 122; and the third distributor 131 is disposed between the upper feed inlet of the third reaction section 13 and the third contact section 132.

[0133] The sodium-containing alkaline solution introduced through the sodium-containing alkaline solution inlet pipe 14 is a 40% sodium hydroxide aqueous solution with a temperature of 40℃ and a pressure of 0.60 MPa. The mass flow rate of the sodium-containing alkaline solution is 3252 kg / h. The sodium-containing alkaline solution first enters the first reaction section 11 of the sodium hydrosulfide reaction tower 1, and then flows into the second reaction section 12 and the third reaction section 13 through the first downcomer 114 and the second downcomer 124, respectively.

[0134] Sodium hydrosulfide is produced using a hydrogen sulfide-containing acidic gas at a temperature of 85℃, a pressure of 50 kPa, and a flow rate of 100 kmol / h as the feed gas. The composition of this hydrogen sulfide-containing acidic gas, by volume fraction (under standard atmospheric pressure and room temperature conditions), includes: hydrogen: 0.06%, water: 15.46%, hydrogen sulfide: 32.52%, ammonia: 48.82%, carbon dioxide: 2.70%, methane: 0.27%, ethane: 0.05%, propane: 0.02%, and butane: 0.10%. After the sodium-containing alkaline solution enters the third reaction section 13, the hydrogen sulfide-containing acidic gas is then introduced into the receiving chamber of the third injector 23.

[0135] like Figure 2 and Figure 3 As shown, a method for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas, and a system adapted to the method, includes: S1. Divide the sodium-containing alkaline solution into three parts: a first-stage sodium-containing alkaline solution, a second-stage sodium-containing alkaline solution, and a third-stage sodium-containing alkaline solution. S2. A portion of the sodium-containing alkaline solution and the hydrogen sulfide-containing acidic gas from the third stage are mixed by a third injection to obtain a third gas-liquid two-phase mixture; S3. The third gas-liquid two-phase mixture and part of the three-stage sodium-containing alkaline solution are subjected to a third countercurrent contact reaction to obtain the third mixed reaction product; S4. The third mixed reaction product is subjected to a third coalescence separation to obtain the third discharged purified gas and a three-stage circulating alkaline solution; S5. The three-stage circulating alkaline solution is pressurized, cooled, and diverted sequentially to obtain a three-stage primary circulating alkaline solution, a three-stage secondary circulating alkaline solution, and sodium hydrosulfide product; wherein, the three-stage secondary circulating alkaline solution is returned to the third spray mixing as a supplementary material for the three-stage sodium-containing alkaline solution; S6. The third-stage purified gas is subjected to a third gas-liquid contact reaction using the three-stage primary circulating alkaline solution and the remaining three-stage sodium-containing alkaline solution to obtain the three-stage effluent alkaline solution and the third-stage purified gas; wherein, the three-stage effluent alkaline solution is returned to the third countercurrent contact reaction as a supplementary material for the three-stage sodium-containing alkaline solution. S7. The third discharge purified gas and part of the second stage sodium-containing alkaline solution are mixed by a second injection to obtain a second gas-liquid two-phase mixture; S8. The second gas-liquid two-phase mixture and part of the second-stage sodium-containing alkaline solution are subjected to a second countercurrent contact reaction to obtain the second mixed reaction product; S9. The second mixed reaction product is subjected to a second coalescence separation to obtain a second discharge purified gas and a second-stage circulating alkaline solution; S10. The two-stage circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a two-stage primary circulating alkaline solution and a two-stage secondary circulating alkaline solution; wherein, the two-stage secondary circulating alkaline solution is returned to the second spray mixing as a supplementary material for the two-stage sodium-containing alkaline solution; S11. The second-stage purified gas is subjected to a second gas-liquid contact reaction using the second-stage primary circulating alkaline solution and the remaining second-stage sodium-containing alkaline solution to obtain a second-stage effluent alkaline solution, a third-stage feed alkaline solution, and a second-effluent purified gas. The third-stage feed alkaline solution is mixed with the third-stage primary circulating alkaline solution and returned to the third gas-liquid contact reaction as the third-stage primary circulating alkaline solution. A portion of the second-stage effluent alkaline solution is returned to the second countercurrent contact reaction as a supplement to the second-stage sodium-containing alkaline solution. The remaining second-stage effluent alkaline solution is used as a supplement to the third-stage sodium-containing alkaline solution. S12. The second discharge purified gas and part of the first stage sodium-containing alkaline solution are mixed by first injection to obtain a first gas-liquid two-phase mixture; S13. The first gas-liquid two-phase mixture and the remaining sodium-containing alkaline solution are subjected to a first countercurrent contact reaction to obtain the first mixed reaction product; S14. The first mixed reaction product is subjected to first coalescence separation to obtain first discharged purified gas and a first-stage circulating alkaline solution; S15. The circulating alkaline solution is pressurized, cooled and split sequentially to obtain a primary circulating alkaline solution and a secondary circulating alkaline solution; wherein, the secondary circulating alkaline solution is returned to the first spray mixing as a supplementary material for the sodium-containing alkaline solution. S16. The first-stage circulating alkali solution and the remaining sodium-containing alkali solution are used to perform a first gas-liquid contact reaction on the first-stage effluent purified gas to obtain a first-stage effluent alkali solution, a second-stage feed alkali solution, and tail gas; wherein, the second-stage feed alkali solution is mixed with the second-stage first-stage circulating alkali solution and returned to the second gas-liquid contact reaction as the second-stage first-stage circulating alkali solution; a portion of the first-stage effluent alkali solution is returned to the first countercurrent contact reaction as a supplement to the first-stage sodium-containing alkali solution; and the remaining first-stage effluent alkali solution is used as a supplement to the second-stage sodium-containing alkali solution.

[0136] The temperature of the first injection mixture is 56°C, and the pressure of the first injection mixture is 50 kPa.

[0137] The temperature of the second injection mixture is 58°C, and the pressure of the second injection mixture is 55 kPa.

[0138] The temperature of the third injection mixture is 62℃, and the pressure of the third injection mixture is 60kPa.

[0139] The mixing times for the first, second, and third injections range from 0.005 s to 0.400 s, respectively.

[0140] The temperature of the first gas-liquid contact reaction is 62℃, and the pressure of the first gas-liquid contact reaction is 30kPa.

[0141] The temperature of the second gas-liquid contact reaction is 66℃, and the pressure of the second gas-liquid contact reaction is 35kPa.

[0142] The temperature of the third gas-liquid contact reaction is 70℃, and the pressure of the third gas-liquid contact reaction is 40kPa.

[0143] The operating temperature of the first cooler 51 is 40℃; the operating temperature of the second cooler 52 is 40℃; and the operating temperature of the third cooler 53 is 40℃.

[0144] The flow rate of the three-stage primary circulating alkaline solution is 2.0 times that of the sodium-containing alkaline solution, and the flow rate of the three-stage secondary circulating alkaline solution is 4.0 times that of the sodium-containing alkaline solution. The flow rate of the primary circulating alkaline solution in the second stage is 2.0 times that of the sodium-containing alkaline solution, and the flow rate of the secondary circulating alkaline solution in the second stage is 4.0 times that of the sodium-containing alkaline solution. The flow rate of the primary circulating alkaline solution is 2.0 times that of the sodium-containing alkaline solution, and the flow rate of the secondary circulating alkaline solution is 4.0 times that of the sodium-containing alkaline solution.

[0145] The gas-liquid two-phase mixture flow velocities for the first, second, and third countercurrent contact reactions were 7.6 m / s, 6.8 m / s, and 5.2 m / s, respectively; and the reaction times for the first, second, and third countercurrent contact reactions were 6.1 s, 6.9 s, and 8.9 s, respectively.

[0146] Example 2 Compared to Example 1, Example 2 differs as follows; all other aspects are the same: The flow rate of the three-stage primary circulating alkaline solution is 3.0 times that of the sodium-containing alkaline solution; The flow rate of the second-stage primary circulating alkaline solution is 3.0 times that of the sodium-containing alkaline solution; The flow rate of the primary circulating alkaline solution is 4.0 times that of the sodium-containing alkaline solution.

[0147] Example 3 Compared to Example 1, Example 3 differs as follows; all other aspects are the same: The mass flow rate of the sodium-containing alkaline solution is 6550 kg / h.

[0148] The flow rate of the three-stage primary circulating alkaline solution is 1.0 times that of the sodium-containing alkaline solution, and the flow rate of the three-stage secondary circulating alkaline solution is 2.0 times that of the sodium-containing alkaline solution. The flow rate of the primary circulating alkaline solution in the second stage is 1.0 times that of the sodium-containing alkaline solution, and the flow rate of the secondary circulating alkaline solution in the second stage is 2.0 times that of the sodium-containing alkaline solution. The flow rate of the primary circulating alkaline solution is 1.0 times that of the sodium-containing alkaline solution, and the flow rate of the secondary circulating alkaline solution is 2.0 times that of the sodium-containing alkaline solution.

[0149] Comparative Example 1 Compared to Example 1, Comparative Example 1 differs as follows, while all other aspects remain the same: The apparatus for producing sodium hydrosulfide disclosed in CN104645811A mainly consists of a water washing tower, parallel sodium hydrosulfide reactors A and B, a circulating alkali tank, and a fresh alkali tank. Hydrogen sulfide-containing acidic gas first enters the water washing tower from the bottom or middle section, while fresh water enters from the top. The hydrogen sulfide-containing acidic gas and fresh water undergo gas-liquid contact at the radial side-guided injection tray at the top of the water washing tower. Simultaneously, the gas phase load of the water washing tower is increased through an inert gas replenishment pipeline, ensuring that the ammonia content in the top gas of the water washing tower reaches 150 ppm. The top gas then subsequently enters either sodium hydrosulfide reactor 2 or sodium hydrosulfide reactor 3 for reaction.

[0150] Relevant experimental and effect data: 1. Material distribution: The material inflow and outflow of the system in Example 1 are statistically analyzed, and the results are shown in Table 1.

[0151] Table 1. Material inflow and outflow of the system in Example 1

[0152] As shown in Table 1, after treating the hydrogen sulfide-containing acidic gas using the system provided in this application embodiment, a sodium hydrosulfide liquid product with a mass flow rate of 4454.843 kg / h and a mass fraction of 40.9146% can be obtained. Subsequent drying yields a sodium hydrosulfide solid product. The concentration and impurity content of this sodium hydrosulfide liquid product meet the requirements of the "Industrial Sodium Hydrosulfide" standard (GB / T 23937-2020). Simultaneously, the system can also obtain a low-hydrogen sulfide tail gas with a hydrogen sulfide mole fraction of 0.000094. After incineration, this tail gas meets the emission standard of "Emission Standard of Pollutants for Petroleum Refining Industry" (GB31570-2015) for SO2 concentration ≤400 mg / Nm³. 3 Require.

[0153] 2. The impact of the designs of each embodiment and comparative example on the product or exhaust gas: Example 2, by adjusting the flow rates of different circulating alkaline solutions, yielded a sodium hydrosulfide liquid product similar to that of Example 1. This sodium hydrosulfide liquid product had a mass flow rate of 4456.2177 kg / h and a mass fraction of 40.9151%, with a hydrogen sulfide mole fraction in the tail gas of 0.000047. This demonstrates that adjusting the flow rates of different circulating alkaline solutions significantly reduced the hydrogen sulfide mole fraction in the tail gas of Example 2 compared to 0.000094 in Example 1. Therefore, adjusting operating conditions, such as adjusting the flow rates of each circulating alkaline solution, can effectively reduce the hydrogen sulfide mole fraction in the tail gas.

[0154] After implementing Example 3, 7795.76 kg / h of liquid sodium sulfide with a mass fraction of 32.5534% can be produced. This liquid sodium sulfide, after crystallization and drying, becomes solid sodium sulfide that meets the requirements of the standard "Industrial Sodium Sulfide" (GB / T 10500-2009), and the molar fraction of hydrogen sulfide in the exhaust gas is 0.000089. It is evident that the system provided in this application has a wide range of applications; by adjusting the operating conditions, it can produce not only sodium hydrosulfide but also sodium sulfide products that meet relevant standards.

[0155] Compared to the conventional sodium hydrosulfide production unit used in Comparative Example 1, the water washing tower used in this unit generates a large amount of wastewater containing sulfur and ammonia, and the molar fraction of hydrogen sulfide in the final tail gas is difficult to reach below 0.00010, which is detrimental to environmental protection. In addition, the overall production time of this unit is relatively long. In contrast, the reaction equipment in the system provided in this application embodiment is highly coupled, forming a multi-stage series reaction only through gas-liquid contact reactions in different gas-liquid contact sections and countercurrent contact reactions in different separation devices. The time consumed by each gas-liquid contact reaction and countercurrent contact reaction is short, which can reduce the amount of by-reaction products (such as sodium carbonate and sodium bicarbonate) generated in the sodium hydrosulfide product and increase the yield of sodium hydrosulfide product.

[0156] In summary, the embodiments of this application provide a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas. Through the core structural design of three-stage countercurrent absorption, multi-stage injection circulation, secondary spraying in the separation device, and optimized anti-channeling structure, this system can significantly reduce the hydrogen sulfide content in the exhaust gas and increase the yield of sodium hydrosulfide products.

[0157] In summary, the embodiments of this application provide a system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas. This system, through sodium hydrosulfide reaction units in a first reaction section 11, a second reaction section 12, and a third reaction section 13, couples a first injector 21, a first separation device, a first sprayer 25, a first circulating cooling device, a second injector 22, a second separation device, a second sprayer 26, a second circulating cooling device, a third injector 23, a third separation device, a third sprayer 27, and a third circulating cooling device. This promotes a multi-stage series reaction between sodium-containing alkaline solution and hydrogen sulfide-containing acidic gas. Each stage of the reaction has a short reaction time, which can reduce the amount of by-products generated in the sodium hydrosulfide product. Simultaneously, it can improve the purity and yield of the sodium hydrosulfide product. It features high resource utilization, high selectivity for sodium hydrosulfide, a simple process, and flexible operation.

[0158] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A system for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas, characterized in that, The system includes: A sodium hydrosulfide reaction unit includes a sodium hydrosulfide reaction tower, a first isolation element, a second isolation element, a gas-liquid separator, and a sodium-containing alkaline solution inlet pipe. The first and second isolation elements are disposed within the sodium hydrosulfide reaction tower to divide the tower into a first reaction section, a second reaction section, and a third reaction section. A first contact section is provided in the first reaction section, a second contact section is provided in the second reaction section, and a third contact section is provided in the third reaction section. The gas-liquid separator is fixedly connected to the top of the sodium hydrosulfide reaction tower. The outlet of the sodium-containing alkaline solution inlet pipe is connected to the upper part of the reaction tower and is located between the first contact section and the gas-liquid separator. The injection circulation unit includes a hydrogen sulfide-containing acidic gas inlet pipe, a first injector, a first separation device, a first sprayer, a first circulating cooling device, a third injector, a third separation device, a third sprayer, and a third circulating cooling device. The outlet of the hydrogen sulfide-containing acidic gas inlet pipe is connected to the inlet of the third injector. The outlet of the third injector is connected to the inlet of the third separation device. The bottom liquid outlet of the sodium hydrosulfide reaction tower is connected to the liquid outlet of the third separation device. The outlet of the third separation device is connected to the lower inlet of the third reaction section and the inlet of the third circulating cooling device. The outlet of the third circulating cooling device is connected to the inlet of the third injector and the upper inlet of the third reaction section. The third sprayer is located inside the third separation device, and the inlet of the third sprayer is connected to the bottom liquid outlet of the sodium hydrosulfide reaction tower. The inlet of the first injector is connected to the upper outlet of the second reaction section, the outlet of the first injector is connected to the inlet of the first separation device, the outlet of the first separation device is connected to the lower inlet of the first reaction section and the inlet of the first circulating cooling device, the outlet of the first circulating cooling device is connected to the inlet of the first injector and the upper inlet of the first reaction section, the upper inlet of the first reaction section is symmetrically arranged with the sodium-containing alkaline solution inlet pipe, the first sprayer is arranged in the first separation device, and the inlet of the first sprayer is connected to the outlet of the first reaction section. A sodium hydrosulfide discharge pipe, the inlet of which is connected to the outlet of the first circulating cooling device.

2. The system according to claim 1, characterized in that, The spray circulation unit further includes a second injector, a second separation device, a second sprayer, and a second circulating cooling device. The inlet of the second injector is connected to the upper outlet of the second reaction section, and the outlet of the second injector is connected to the inlet of the second separation device. The outlet of the second separation device is connected to the lower inlet of the second reaction section and the inlet of the second circulating cooling device, respectively. The outlet of the second circulating cooling device is connected to the inlet of the second injector and the upper inlet of the second reaction section, respectively. The second sprayer is disposed inside the second separation device, and the inlet of the second sprayer is connected to the bottom liquid outlet of the second reaction section.

3. The system according to claim 2, characterized in that, The second separation device includes a second separation tank and a second liquid chamber, a second gas chamber, and a second coalescer disposed within the second separation tank. The inlet of the second separation tank is connected to the outlet of the second ejector, and the second coalescer is disposed at one end of the second separation tank. In accordance with the gas diffusion direction, the second liquid chamber is disposed downstream of the second coalescer, and the second gas chamber is symmetrically disposed with respect to the second liquid chamber. The outlet of the second gas chamber is connected to the lower inlet of the second reaction section, and the outlet of the second liquid chamber is connected to the second circulating cooling device.

4. The system according to claim 3, characterized in that, The second circulating cooling device includes: a second circulating pump and a second cooler. The inlet of the second circulating pump is connected to the outlet of the second liquid tank, and the outlet of the second circulating pump is connected to the inlet of the second cooler. The outlet of the second cooler is connected to the inlet of the second injector and the upper inlet of the second reaction section, respectively.

5. The system according to claim 1, characterized in that, The first separation device includes a first separation tank and a first liquid chamber, a first gas chamber, and a first coalescer disposed within the first separation tank. The inlet of the first separation tank is connected to the outlet of the first ejector, and the first coalescer is disposed at one end of the first separation tank. According to the gas diffusion direction, the first liquid chamber is disposed downstream of the first coalescer, and the first gas chamber is symmetrically disposed with respect to the first liquid chamber. The outlet of the first gas chamber is connected to the lower inlet of the first reaction section, and the outlet of the first liquid chamber is connected to the second circulating cooling device. The third separation device includes a third separation tank and a third liquid chamber, a third gas chamber, and a third coalescer disposed within the third separation tank. The inlet of the third separation tank is connected to the outlet of the third ejector, and the third coalescer is disposed at one end of the third separation tank. In accordance with the gas diffusion direction, the third liquid chamber is disposed downstream of the third coalescer, and the third gas chamber is symmetrically disposed with respect to the third liquid chamber. The outlet of the third gas chamber is connected to the lower inlet of the third reaction section, and the outlet of the third liquid chamber is connected to the second circulating cooling device.

6. The system according to claim 1 or 5, characterized in that, The first circulating cooling device includes a first circulating pump and a first cooler. The inlet of the first circulating pump is connected to the outlet of the first liquid tank, the outlet of the first circulating pump is connected to the inlet of the first cooler, and the outlet of the first cooler is connected to the inlet of the first injector and the upper inlet of the first reaction section, respectively. The third circulating cooling device includes a third circulating pump and a third cooler. The inlet of the third circulating pump is connected to the outlet of the third liquid tank, and the outlet of the third circulating pump is connected to the inlet of the third cooler. The outlet of the third cooler is connected to the inlet of the third injector and the upper inlet of the third reaction section, respectively.

7. The system according to claim 1, characterized in that, The sodium hydrosulfide reaction unit further includes: a first downcomer and a second downcomer. The first downcomer penetrates the first isolation element, and a gas-blocking sealing plate is provided at the bottom end of the first downcomer to isolate gas exchange between the first reaction section and the second reaction section. The second downcomer penetrates the second isolation chamber, and a gas-blocking sealing plate is provided at the bottom end of the second downcomer to isolate gas exchange between the second reaction section and the third reaction section.

8. The system according to claim 1, characterized in that, The formula for calculating the diameter of the first downcomer or the second downcomer is: Equation 1; A = 0.785D 2 , Equation 2; In Equation 1, f is the coefficient of friction; when D ≤ 0.015m, f is 0.027; when D ≥ 0.100m, f is 0.017; when 0.015m < D < 0.100m, f satisfies the following: Equation 3; In Equations 1, 2, and 3, Q represents the liquid volumetric flow rate through the first downcomer or the second downcomer, in m³ / s. 3 / s;C d is the flow coefficient, with a value of 0.65; A is the cross-sectional area of ​​the first downcomer or the second downcomer, in meters. 2 h represents the vertical height difference between the first downcomer and the second downcomer, in meters (m); g represents the acceleration due to gravity, with a value of 9.81 m / s². 2 D is the diameter of the first downcomer or the second downcomer, in meters; L is the length of the first downcomer or the second downcomer, in meters.

9. The system according to claim 1, characterized in that, The sodium hydrosulfide reaction unit further includes: a first distributor, a second distributor, and a third distributor. The first distributor is disposed between the sodium-containing alkali inlet pipe and the first contact section; the second distributor is disposed above the second contact section; and the third distributor is disposed between the upper feed inlet of the third reaction section and the third contact section.

10. A method for preparing sodium hydrosulfide based on hydrogen sulfide-containing acidic gas, characterized in that, The method is adapted to the system according to any one of claims 1 to 9, and the method includes: The sodium-containing alkaline solution is divided into three stages: a first-stage sodium-containing alkaline solution, a second-stage sodium-containing alkaline solution, and a third-stage sodium-containing alkaline solution. A portion of the three sections containing sodium-containing alkaline solution and hydrogen sulfide-containing acidic gas are mixed by a third injection to obtain a third gas-liquid two-phase mixture; The third gas-liquid two-phase mixture and a portion of the three sodium-containing alkaline solutions are subjected to a third countercurrent contact reaction to obtain a third mixed reaction product. The third mixed reaction product is subjected to a third coalescence separation to obtain a third discharged purified gas and a three-stage circulating alkaline solution. The three-stage circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a three-stage primary circulating alkaline solution, a three-stage secondary circulating alkaline solution, and sodium hydrosulfide product; wherein, the three-stage secondary circulating alkaline solution is returned to the third spray mixing process as a supplementary feed for the three-stage sodium-containing alkaline solution; The third effluent purified gas is subjected to a third gas-liquid contact reaction using a portion of the three-stage primary circulating alkaline solution and the remaining three-stage sodium-containing alkaline solution to obtain three-stage effluent alkaline solution and third effluent purified gas; wherein, the three-stage effluent alkaline solution is returned to the third countercurrent contact reaction as a supplement to the three-stage sodium-containing alkaline solution. The third discharge purified gas and part of the second stage sodium-containing alkaline solution are mixed by a second injection to obtain a second gas-liquid two-phase mixture. The second gas-liquid two-phase mixture and a portion of the second sodium-containing alkaline solution are subjected to a second countercurrent contact reaction to obtain a second mixed reaction product. The second mixed reaction product is subjected to a second coalescence separation to obtain a second discharged purified gas and a second-stage circulating alkaline solution. The two-stage circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a two-stage primary circulating alkaline solution and a two-stage secondary circulating alkaline solution; wherein, the two-stage secondary circulating alkaline solution is returned to the second spray mixing as a supplementary material for the two-stage sodium-containing alkaline solution; The second-stage purified effluent is subjected to a second gas-liquid contact reaction using the second-stage primary circulating alkali solution and the remaining second-stage sodium-containing alkali solution to obtain a second-stage effluent alkali solution, a third-stage feed alkali solution, and a second-effluent purified gas. The third-stage feed alkali solution is mixed with the remaining third-stage primary circulating alkali solution and returned to the third gas-liquid contact reaction as the third-stage primary circulating alkali solution. A portion of the second-stage effluent alkali solution is returned to the second countercurrent contact reaction as a supplement to the second-stage sodium-containing alkali solution. The remaining second-stage effluent alkali solution is used as a supplement to the third-stage sodium-containing alkali solution. The second discharged purified gas and a portion of the sodium-containing alkaline solution in the first injection are mixed to obtain a first gas-liquid two-phase mixture. The first gas-liquid two-phase mixture and a portion of the sodium-containing alkaline solution are subjected to a first countercurrent contact reaction to obtain a first mixed reaction product. The first mixed reaction product is subjected to a first coalescence separation to obtain a first discharge purified gas and a first-stage circulating alkaline solution. The circulating alkaline solution is sequentially pressurized, cooled, and diverted to obtain a primary circulating alkaline solution and a secondary circulating alkaline solution; wherein, the secondary circulating alkaline solution is returned to the first spray mixing process as a supplement to the sodium-containing alkaline solution. The first-stage circulating alkali solution and the remaining first-stage sodium-containing alkali solution are used to perform a first gas-liquid contact reaction on the first-stage effluent purified gas to obtain a first-stage effluent alkali solution, a second-stage feed alkali solution, and tail gas. The second-stage feed alkali solution is mixed with the second-stage first-stage circulating alkali solution and returned to the second gas-liquid contact reaction as the second-stage first-stage circulating alkali solution. A portion of the first-stage effluent alkali solution is returned to the first countercurrent contact reaction as a supplement to the first-stage sodium-containing alkali solution. The remaining first-stage effluent alkali solution is used as a supplement to the second-stage sodium-containing alkali solution.

11. The method according to claim 10, characterized in that, The temperatures of the first, second, and third injection mixtures are 50°C to 80°C, the times of the first, second, and third injection mixtures are 0.005s to 0.400s, and the pressures of the first, second, and third injection mixtures are greater than or equal to 25kPa.

12. The method according to claim 10, characterized in that, The temperatures of the first gas-liquid contact reaction, the second gas-liquid contact reaction, and the third gas-liquid contact reaction are 45°C to 75°C, respectively; the pressures of the first gas-liquid contact reaction, the second gas-liquid contact reaction, and the third gas-liquid contact reaction are each greater than or equal to 5 kPa.

13. The method according to claim 10, characterized in that, The flow rate of the three-stage primary circulating alkaline solution is 0.5 to 6.0 times the flow rate of the sodium-containing alkaline solution, and the flow rate of the three-stage secondary circulating alkaline solution is 1.5 to 15.0 times the flow rate of the sodium-containing alkaline solution; and / or The flow rate of the primary circulating alkaline solution in the second stage is 0.5 to 6.0 times the flow rate of the sodium-containing alkaline solution, and the flow rate of the secondary circulating alkaline solution in the second stage is 1.5 to 15.0 times the flow rate of the sodium-containing alkaline solution; and / or The flow rate of the first-stage circulating alkaline solution is 0.5 to 6.0 times that of the sodium-containing alkaline solution, and the flow rate of the second-stage circulating alkaline solution is 1.5 to 15.0 times that of the sodium-containing alkaline solution.

14. The method according to claim 10, characterized in that, The gas-liquid two-phase mixture flow rates of the first countercurrent contact reaction, the second countercurrent contact reaction, and the third countercurrent contact reaction are 1.0 m / s to 8.0 m / s, respectively, and the times of the first countercurrent contact reaction, the second countercurrent contact reaction, and the third countercurrent contact reaction are 0.5 s to 15 s, respectively.

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