A method for preparing a carbonyl sulfur hydrolysis catalyst and its application

Abstract

This invention relates to the field of gas purification and chemical catalyst technology, and discloses a method for preparing a carbonyl sulfur hydrolysis catalyst and its application. The method includes the following steps: a carbonyl sulfur hydrolysis catalyst is prepared from sulfolane, monopropanolamine, tripropanolamine, and water through temperature-controlled miscibility and precision filtration; the application method involves spraying the carbonyl sulfur hydrolysis catalyst into an absorption tower, constructing a dual-temperature zone within the absorption tower; maintaining a high temperature in the lower region of the absorption tower, utilizing monopropanolamine to catalyze the hydrolysis of carbon disulfide and carbonyl sulfur; maintaining a low temperature in the upper region of the absorption tower, utilizing tripropanolamine to absorb hydrogen sulfide and carbon dioxide; the carbonyl sulfur hydrolysis catalyst that has absorbed the gases is transported to a desorption tower, where hydrogen sulfide and carbon dioxide are desorbed under high temperature and negative pressure as product gases; the regenerated solution is recycled. This invention resolves the contradiction between carbon disulfide hydrolysis and product absorption, realizing the conversion and resource recovery of organic sulfur.

Description

Technical Field

[0001] This invention relates to the field of gas purification and chemical catalyst technology, specifically to a method for preparing a carbonyl sulfur hydrolysis catalyst and its application. Background Technology

[0002] In the processes of coal chemical industry, petroleum refining, and chemical fiber production, industrial waste gases containing carbon disulfide, carbonyl sulfide, and carbon dioxide are frequently generated. Carbon disulfide and carbonyl sulfide are organic sulfides with relatively stable chemical properties and low solubility in water, making them far more difficult to treat than inorganic sulfur compounds such as hydrogen sulfide. Existing wet desulfurization technologies use alkanolamine solutions as absorbents, but these have limitations when treating complex waste gases containing carbon disulfide. Traditional single-component alkanolamine aqueous solutions have limited physical dissolution capacity for carbon disulfide, resulting in high gas-liquid mass transfer resistance and limiting the reaction rate. At the same time, a single alkanolamine component cannot simultaneously achieve both efficient hydrolysis catalysis of organic sulfur and high-capacity absorption of acidic products, leading to incomplete conversion of organic sulfur or substandard purification levels when treating high-concentration or fluctuating sulfur-containing waste gases.

[0003] Furthermore, in terms of process control, existing absorption tower equipment employs a single temperature control strategy, which cannot resolve the contradiction between the kinetics of carbon disulfide hydrolysis and the thermodynamics of acid gas absorption. The hydrolysis of carbon disulfide and carbonyl sulfide requires higher temperatures to overcome and increase the reaction rate; however, the absorption of hydrogen sulfide and carbon dioxide generated in the reaction is an exothermic reaction, and lower temperatures are beneficial for increasing the equilibrium solubility of the gas in the liquid phase and inhibiting desorption. If the existing isothermal absorption process maintains low-temperature operation, it will inhibit the hydrolysis rate of organic sulfur, leading to the escape of organic sulfur; if it maintains high-temperature operation, the generated acid gas will not be captured and will undergo reverse desorption. This conflict in temperature requirements makes it difficult for existing technologies to simultaneously achieve the hydrolysis of organic sulfur and the recovery of inorganic products within a single absorption device.

[0004] In terms of regeneration and resource utilization, conventional desulfurizing agent regeneration processes suffer from high energy consumption and incomplete desorption. If regeneration conditions are not properly controlled, hydrogen sulfide and carbon dioxide are difficult to completely separate from the rich solution, resulting in the lean solution still containing a high acidic gas load, which reduces absorption efficiency. Furthermore, some existing technologies fail to recover the converted sulfur resources, treating them as waste. This not only increases the cost of subsequent environmental treatment but also wastes industrially valuable hydrogen sulfide and carbon dioxide resources, failing to meet the requirements of modern chemical industry for energy conservation, emission reduction, and resource recycling. Therefore, this invention proposes a method for preparing a carbonyl sulfur hydrolysis catalyst and its application to address the shortcomings of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing a carbonyl sulfur hydrolysis catalyst and its application. This method solves the problems of poor solubility of carbon disulfide in existing single-component absorbents, difficulty in simultaneously achieving hydrolysis catalysis and absorption capabilities, and temperature conflicts between the hydrolysis kinetics of carbon disulfide and the thermodynamics of product absorption in traditional single-temperature absorption processes, which lead to incomplete organic sulfur conversion, low acid gas capture efficiency, and low resource utilization rate.

[0006] To achieve the above objectives, the present invention provides the following technical solution: Firstly, the present invention provides a method for preparing a carbonyl sulfur hydrolysis catalyst, comprising the following steps:

[0007] Under mechanical stirring, water, sulfolane, monopropanolamine, and tripropanolamine are added sequentially to the mixing vessel;

[0008] Control the temperature inside the mixing vessel to 20℃-30℃, and continue stirring until sulfolane, monopropanolamine, tripropanolamine and water are completely miscible to form a homogeneous transparent liquid;

[0009] A homogeneous transparent liquid was filtered through a filter element with a pore size of 3μm-7μm to obtain a carbonyl sulfur hydrolysis catalyst.

[0010] By employing the above technical solution, the specific sequence of mixing and temperature-controlled dissolution processes ensures uniform dispersion of the organic solvent sulfolane, alkanolamines, and water at the molecular level. Maintaining the temperature within the mixing vessel at 20℃-30℃ prevents the monopropanolamine and tripropanolamine from oxidizing and deteriorating due to localized overheating during preparation. Simultaneously, it avoids excessive viscosity of sulfolane due to low temperatures, which could negatively impact mixing. Precision filtration using a 5μm filter removes trace solid particles and mechanical impurities that may be present in the raw materials, preventing the carbonyl sulfide hydrolysis catalyst from clogging the absorber distributor or wearing down the delivery pump in subsequent applications.

[0011] Preferably, the weight parts of sulfolane are 30.0-60.0; the weight parts of monopropanolamine are 20.0-30.0; the weight parts of tripropanolamine are 10.0-20.0; and the weight parts of water are 10.0-20.0.

[0012] By adopting the above technical solution, a composite system with both physical solubility and chemical reactivity was constructed. In this formulation system, sulfolane serves as a physical solvent, utilizing its high solubility for organic sulfides to reduce gas-liquid mass transfer resistance and rapidly transfer carbon disulfide and carbonyl sulfide from the gas phase to the liquid phase. Monopropanolamine, as a primary alcohol amine, has the characteristics of low steric hindrance and high reactivity. Monopropanolamine mainly undertakes the task of nucleophilic attack on carbon disulfide carbon atoms and is the core catalytic component of the hydrolysis reaction. Tripropanolamine, as a tertiary alcohol amine, has strong basicity and relatively low heat of reaction. Tripropanolamine mainly undertakes the task of absorbing and buffering acidic gases and is easily desorbed during regeneration. Water, as a necessary reactant in the hydrolysis reaction, directly participates in the chemical conversion. The components work synergistically within the above-mentioned proportion range to achieve high conversion rate and high stability under high sulfur load.

[0013] Secondly, this invention provides an application of a carbonyl sulfur hydrolysis catalyst, employing the following technical solution:

[0014] The application of a carbonyl sulfur hydrolysis catalyst, applied to the carbonyl sulfur hydrolysis catalyst prepared in the first aspect, includes the following steps:

[0015] S1. The gas containing carbonyl sulfide, carbon disulfide and carbon dioxide is heated and then introduced into the bottom of the absorption tower;

[0016] S2. The carbonyl sulfide hydrolysis catalyst is sprayed into the absorption tower from the top as the absorbent. Two different temperature control zones are constructed inside the absorption tower. The lower zone of the absorption tower is the hydrolysis reaction zone, and the liquid phase temperature in the lower zone is maintained higher than the gas-liquid contact temperature in the upper zone. In the lower zone, monopropanolamine in the carbonyl sulfide hydrolysis catalyst catalyzes the hydrolysis of carbon disulfide and carbonyl sulfide to produce hydrogen sulfide and carbon dioxide. At the same time, in the upper zone, tripropanolamine in the carbonyl sulfide hydrolysis catalyst absorbs hydrogen sulfide and carbon dioxide.

[0017] S3. The rich liquid that has absorbed hydrogen sulfide and carbon dioxide discharged from the bottom of the absorption tower is transported to the desorption tower, where hydrogen sulfide and carbon dioxide are desorbed as product gas under high temperature and negative pressure conditions.

[0018] S4. The lean liquid flowing from the bottom of the analytical column is cooled and then sent back to the top of the absorption column for recycling.

[0019] By adopting the above technical solution, this invention innovatively constructs a dual-functional temperature zone within a single absorption tower, consisting of high-temperature hydrolysis at the bottom and low-temperature absorption at the top, thus resolving the contradiction between the hydrolysis rate of carbon disulfide and the product absorption balance. The specific mechanism is explained below:

[0020] First, in the lower region of the absorber, the higher liquid-phase temperature provides the activation energy required for the hydrolysis reaction. When the gas containing carbonyl sulfide and carbon disulfide enters the lower region of the absorber, sulfolane rapidly dissolves the carbon disulfide. Subsequently, monopropanolamine, acting as a nucleophile, attacks the carbon atoms in the carbon disulfide molecule, forming a dithiocarbamate intermediate. With the participation of water molecules, the intermediate rapidly decomposes, releasing hydrogen sulfide and generating carbonyl sulfide. The carbonyl sulfide further undergoes similar nucleophilic addition and hydrolysis reactions with monopropanolamine and water, ultimately being completely converted into carbon dioxide and hydrogen sulfide. Monopropanolamine plays a crucial role in this process by transferring protons and catalyzing hydrolysis. The high-temperature environment enhances the kinetic rate of this series of chemical reactions, ensuring that the carbon disulfide is fully converted before escaping the lower region of the absorber in the gas phase.

[0021] Secondly, in the upper region of the absorption tower, the lower gas-liquid contact temperature is conducive to increasing the equilibrium load of the amine solution on the acidic gas. The reaction products hydrogen sulfide and carbon dioxide, as well as trace amounts of unreacted gas, which rise from the lower region of the absorption tower, enter the upper region of the absorption tower. At this time, the tripropanolamine in the carbonyl sulfide hydrolysis catalyst utilizes its own alkalinity to efficiently capture hydrogen sulfide and carbon dioxide through an acid-base neutralization reaction, fixing hydrogen sulfide and carbon dioxide in ionic form in the liquid phase. The low temperature environment inhibits the occurrence of the reverse reaction and reduces the equilibrium partial pressure of hydrogen sulfide and carbon dioxide, thereby ensuring the purification degree of the gas discharged from the top of the tower.

[0022] Preferably, in step S2, the liquid phase temperature in the lower region of the absorption tower is controlled at 60℃-75℃; and the gas-liquid contact temperature in the upper region of the absorption tower is controlled at 40℃-50℃.

[0023] By adopting the above technical solution, the liquid phase temperature in the lower region of the absorption tower is controlled at 60℃-75℃, which maximizes the hydrolysis rate constant of carbon disulfide and avoids the loss of sulfolane volatilization or thermal degradation of monopropanolamine due to excessive temperature. The gas-liquid contact temperature in the upper region of the absorption tower is controlled at 40℃-50℃, which maintains the high absorption capacity of tripropanolamine for hydrogen sulfide and prevents the absorption efficiency from decreasing due to the accumulation of absorption heat, thus achieving a match between reaction kinetics and thermodynamic equilibrium.

[0024] Preferably, in step S2, the temperature of the rising gas flow and the flowing liquid is cooled by an interstage cooler located in the middle of the absorption tower to maintain the gas-liquid contact temperature in the upper region of the absorption tower; the liquid phase temperature in the lower region of the absorption tower is maintained by the tower bottom heating and reaction heat.

[0025] By adopting the above technical solution, the interstage cooler forcibly removes the sensible heat brought by the high-temperature gas at the bottom and the heat of dissolution generated by the absorption process at the top, establishing a steep and stable temperature gradient inside the absorption tower, physically isolating the thermal interference between the hydrolysis zone and the absorption zone, and ensuring the stability of the dual-temperature zone process.

[0026] Preferably, in step S2, the liquid-to-gas ratio of the carbonyl sulfide hydrolysis catalyst to the gas containing carbonyl sulfide and carbon disulfide is controlled to be 2.0 L / m³. 3 -5.0L / m 3 The operating pressure of the absorption tower is controlled between 1.2 bar and 4.0 bar.

[0027] By adopting the above technical solution, 2.0L / m 3 -5.0L / m 3 The liquid-to-gas ratio ensures sufficient wetting of the carbonyl sulfur hydrolysis catalyst on the packing surface, providing adequate gas-liquid contact area while avoiding flooding. The operating pressure of 1.2 bar to 4.0 bar increases the partial pressure of carbon disulfide in the carbonyl sulfur hydrolysis catalyst, which, according to Henry's Law, increases the concentration of reactants in the liquid phase, thereby further improving the reaction rate.

[0028] Preferably, in step S2, the temperature of the carbonyl sulfur hydrolysis catalyst sprayed into the absorption tower from the top of the absorption tower is controlled at 40℃-50℃.

[0029] By adopting the above technical solution, the low-temperature lean liquid is directly used as a cold source to help maintain the low-temperature environment in the upper region of the absorption tower, thereby reducing the heat load of the interstage cooler and realizing the rational utilization of energy.

[0030] Preferably, in step S3, the temperature at the bottom of the analytical column is controlled at 125℃-145℃, and the pressure at the top of the analytical column is controlled at 10kPa-25kPa.

[0031] By adopting the above technical solution, the high temperature of 125℃-145℃ can break the salt chemical bonds formed by tripropanolamine with hydrogen sulfide and carbon dioxide; combined with the negative pressure environment of 10kPa-25kPa, the partial pressure of acidic components in the gas phase is reduced.

[0032] Preferably, in step S1, the gas containing carbonyl sulfide and carbon disulfide is heated to 50°C-80°C and then introduced into the bottom of the absorption tower.

[0033] By adopting the above technical solution, the intake air is preheated, which prevents the cold airflow from entering the bottom of the absorption tower and causing a sudden drop in temperature in the hydrolysis reaction zone. This ensures the heat balance during the reaction start-up phase, enabling the system to quickly reach a stable operating state.

[0034] Preferably, in step S4, the lean liquid flowing out from the bottom of the stripping tower is cooled to 40°C-50°C and then sent back to the top of the absorption tower for recycling.

[0035] By adopting the above technical solution, the temperature of the lean liquor to be recycled is precisely matched with the temperature control requirements of the upper region of the absorption tower, thus forming a closed-loop heat and quality management system.

[0036] This invention provides a method for preparing a carbonyl sulfur hydrolysis catalyst and its application. It has the following beneficial effects:

[0037] 1. This invention constructs a synergistic system of physical dissolution and chemical reaction by compounding sulfolane, monopropanolamine, tripropanolamine and water in a specific ratio. Sulfolane, as a physical solvent, improves the gas-liquid mass transfer efficiency of insoluble carbon disulfide. Monopropanolamine utilizes its high nucleophilic activity to achieve rapid hydrolysis and conversion of carbon disulfide and carbonyl sulfide. Tripropanolamine utilizes its high alkalinity to provide a large capacity for absorbing acidic gases. The combined use of these three components enables the carbonyl sulfide hydrolysis catalyst to maintain high sulfur capacity and high conversion rate over a wide operating range, solving the problem of low removal efficiency of organic sulfur by traditional single amine solutions.

[0038] 2. The carbonyl sulfur hydrolysis catalyst provided by this invention adopts a dual-temperature zone control process inside the absorption tower, which solves the contradiction between the hydrolysis kinetics of carbon disulfide and the thermodynamics of product absorption. By maintaining the liquid phase temperature in the lower region of the absorption tower, the activation energy required for the hydrolysis reaction is provided, ensuring the conversion of carbon disulfide. By controlling the gas-liquid contact temperature in the upper region of the absorption tower, the equilibrium solubility of the generated hydrogen sulfide and carbon dioxide by the carbonyl sulfur hydrolysis catalyst is improved, and the back escape of product gas is suppressed. Thus, the deep hydrolysis of organic sulfur and the capture of inorganic products are realized simultaneously in a single tower device.

[0039] 3. This invention achieves the regeneration and resource recovery of carbonyl sulfur hydrolysis catalyst through a high-temperature negative pressure desorption and solution circulation process. In the desorption tower, the high temperature and negative pressure environment is used to break the binding force between the carbonyl sulfur hydrolysis catalyst and hydrogen sulfide and carbon dioxide, so that the absorbent liquid containing the reaction products can be desorbed, releasing high concentrations of hydrogen sulfide and carbon dioxide. After regeneration, the carbonyl sulfur hydrolysis catalyst restores its absorption activity and is cooled and then transported back to the absorption tower for recycling, avoiding the continuous consumption of the catalyst and realizing the resource transformation of carbonyl sulfur-containing waste gas from pollutants to raw material gas. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the preparation examples, comparative examples, and test examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Preparation Examples 1-3:

[0042] Preparation Example 1:

[0043] In a stainless steel mixing vessel equipped with a mechanical stirrer and a temperature control jacket, 15.0 kg of water was first added. The mechanical stirrer was then turned on and set to 200 rpm. While stirring, 45.0 kg of sulfolane, 25.0 kg of monopropanolamine, and 15.0 kg of tripropanolamine were slowly added to the mixing vessel sequentially. After the addition was complete, the temperature inside the mixing vessel was maintained at 25°C, and stirring was continued for 40 minutes until all components were completely miscible, forming a homogeneous and transparent liquid. The mixed liquid was then filtered through a 5 μm polypropylene filter to remove any mechanical impurities, yielding the absorbent.

[0044] Preparation Example 2:

[0045] In a stainless steel mixing vessel equipped with a mechanical stirrer and a temperature control jacket, 10.0 kg of water was first added. The mechanical stirrer was turned on and the speed was set to 200 rpm. While stirring, 60.0 kg of sulfolane, 20.0 kg of monopropanolamine, and 10.0 kg of tripropanolamine were slowly added to the mixing vessel in sequence. After the addition was completed, the temperature inside the mixing vessel was controlled at 25°C, and stirring was continued for 40 minutes until all components were completely miscible and a homogeneous transparent liquid was formed. The mixed liquid was then filtered through a polypropylene filter with a pore size of 5 μm to remove any mechanical impurities and obtain the absorbent liquid.

[0046] Preparation Example 3:

[0047] In a stainless steel mixing vessel equipped with a mechanical stirrer and a temperature control jacket, 20.0 kg of water was first added. The mechanical stirrer was turned on and the speed was set to 200 rpm. While stirring, 30.0 kg of sulfolane, 30.0 kg of monopropanolamine, and 20.0 kg of tripropanolamine were slowly added to the mixing vessel in sequence. After the addition was completed, the temperature inside the mixing vessel was controlled at 25°C, and stirring was continued for 40 minutes until all components were completely miscible and a homogeneous transparent liquid was formed. The mixed liquid was then filtered through a polypropylene filter with a pore size of 5 μm to remove any mechanical impurities and obtain the absorbent liquid.

[0048] Examples 1-3:

[0049] Example 1: This example provides the application of a carbonyl sulfur hydrolysis catalyst, including the following steps:

[0050] Preparation of simulated carbonyl sulfur-containing waste gas: Carbon disulfide, carbonyl sulfur, carbon dioxide, and nitrogen are mixed, and the flow rates of each component are precisely adjusted using a mass flow controller to ensure that the volume concentration of carbon disulfide in the simulated carbonyl sulfur-containing waste gas is 2000 ppm, the volume concentration of carbonyl sulfur is 1000 ppm, the volume concentration of carbon dioxide is 5.0%, and the balance is nitrogen; the simulated carbonyl sulfur-containing waste gas is heated to 60°C and then introduced into the bottom of the absorption tower;

[0051] Dual-temperature zone hydrolysis and absorption: The absorbent obtained in Preparation Example 1 was used as the working medium. The absorbent was sprayed into the absorption tower from the top at a temperature of 45°C, and the liquid-to-gas ratio of the absorbent to the simulated carbonyl sulfur-containing waste gas was controlled at 3.0 L / m³. 3 The operating pressure of the absorption tower is controlled at 2.0 bar. Two different temperature control zones are constructed inside the absorption tower. The lower zone is the hydrolysis reaction zone, where the liquid phase temperature is maintained at 70°C through reboiler heating and reaction heat. At this temperature, monopropanolamine in the absorbent catalyzes the hydrolysis of carbon disulfide and carbonyl sulfide to produce hydrogen sulfide and carbon dioxide. The upper zone is the absorption and capture zone, where an interstage cooler located in the middle of the tower cools the rising gas flow and the flowing liquid, maintaining the gas-liquid contact temperature at 45°C. At this temperature, tripropanolamine in the absorbent absorbs hydrogen sulfide and carbon dioxide. The purified gas is discharged from the top of the absorption tower, and the rich liquid containing absorbed hydrogen sulfide and carbon dioxide is discharged from the bottom.

[0052] Rich liquor desorption and regeneration: The rich liquor discharged from the bottom of the absorption tower is heated by heat exchange and then transported to the desorption tower. The reboiling temperature at the bottom of the desorption tower is controlled at 135℃, and the operating pressure at the top of the desorption tower is controlled at 15kPa. Under high temperature and negative pressure conditions, the dissolved and chemically combined hydrogen sulfide and carbon dioxide in the rich liquor are desorbed, discharged from the top of the desorption tower and collected as product gas.

[0053] Solution circulation: The lean solution flowing out from the bottom of the stripping tower is cooled to 45°C through heat exchange and then pumped back to the top of the absorption tower for reuse.

[0054] Example 2: This example provides the application of a carbonyl sulfur hydrolysis catalyst, including the following steps:

[0055] Preparation of simulated carbonyl sulfur-containing waste gas: Carbon disulfide, carbonyl sulfur, carbon dioxide, and nitrogen are mixed, and the flow rates of each component are precisely adjusted using a mass flow controller to ensure that the volume concentration of carbon disulfide in the simulated carbonyl sulfur-containing waste gas is 3000 ppm, the volume concentration of carbonyl sulfur is 1500 ppm, the volume concentration of carbon dioxide is 8.0%, and the balance is nitrogen; the simulated carbonyl sulfur-containing waste gas is heated to 50°C and then introduced into the bottom of the absorption tower;

[0056] Dual-temperature zone hydrolysis and absorption: The absorbent obtained in Preparation Example 2 was used as the working medium. The absorbent was sprayed into the absorption tower from the top at a temperature of 40°C, and the liquid-to-gas ratio of the absorbent to the simulated carbonyl sulfur-containing waste gas was controlled at 2.0 L / m³. 3 The operating pressure of the absorption tower is controlled at 4.0 bar. Two different temperature control zones are constructed inside the absorption tower. The lower zone is the hydrolysis reaction zone, where the liquid phase temperature is maintained at 60°C through tower bottom heating and reaction heat. At this temperature, monopropanolamine in the absorbent catalyzes the hydrolysis of carbon disulfide and carbonyl sulfide to produce hydrogen sulfide and carbon dioxide. The upper zone is the absorption and capture zone, where an interstage cooler located in the middle of the absorption tower cools the rising gas flow and the flowing liquid, maintaining the gas-liquid contact temperature at 40°C. At this temperature, tripropanolamine in the absorbent absorbs hydrogen sulfide and carbon dioxide. The purified gas is discharged from the top of the absorption tower, and the rich liquid containing absorbed hydrogen sulfide and carbon dioxide is discharged from the bottom of the absorption tower.

[0057] Rich liquor desorption and regeneration: The rich liquor discharged from the bottom of the absorption tower is heated by heat exchange and then transported to the desorption tower. The reboiling temperature at the bottom of the desorption tower is controlled at 145℃, and the operating pressure at the top of the desorption tower is controlled at 10kPa. Under high temperature and negative pressure conditions, the dissolved and chemically combined hydrogen sulfide and carbon dioxide in the rich liquor are desorbed, discharged from the top of the desorption tower and collected as product gas.

[0058] Solution circulation: The lean solution flowing out from the bottom of the stripping tower is cooled to 40°C through heat exchange and then pumped back to the top of the absorption tower for reuse.

[0059] Example 3: This example provides the application of a carbonyl sulfur hydrolysis catalyst, including the following steps:

[0060] Preparation of simulated carbonyl sulfur-containing waste gas: Carbon disulfide, carbonyl sulfur, carbon dioxide, and nitrogen are mixed, and the flow rates of each component are precisely adjusted using a mass flow controller to ensure that the volume concentration of carbon disulfide in the simulated carbonyl sulfur-containing waste gas is 1500 ppm, the volume concentration of carbonyl sulfur is 800 ppm, the volume concentration of carbon dioxide is 3.0%, and the balance is nitrogen; the simulated carbonyl sulfur-containing waste gas is heated to 80°C and then introduced into the bottom of the absorption tower;

[0061] Dual-temperature zone hydrolysis and absorption: The absorbent obtained in Preparation Example 3 was used as the working medium. The absorbent was sprayed into the absorption tower from the top at a temperature of 50°C, and the liquid-to-gas ratio of the absorbent to the simulated carbonyl sulfur-containing waste gas was controlled at 5.0 L / m³. 3The operating pressure of the absorption tower is controlled at 1.2 bar. Two different temperature control zones are constructed inside the absorption tower. The lower zone is the hydrolysis reaction zone, where the liquid phase temperature is maintained at 75°C through reboiler heating and reaction heat. At this temperature, monopropanolamine in the absorbent catalyzes the hydrolysis of carbon disulfide and carbonyl sulfide to produce hydrogen sulfide and carbon dioxide. The upper zone is the absorption and capture zone, where an interstage cooler located in the middle of the absorption tower cools the rising gas flow and the flowing liquid, maintaining the gas-liquid contact temperature at 50°C. At this temperature, tripropanolamine in the absorbent absorbs hydrogen sulfide and carbon dioxide. The purified gas is discharged from the top of the absorption tower, and the rich liquid containing absorbed hydrogen sulfide and carbon dioxide is discharged from the bottom of the absorption tower.

[0062] Rich liquor desorption and regeneration: The rich liquor discharged from the bottom of the absorption tower is heated by heat exchange and then transported to the desorption tower. The reboiling temperature at the bottom of the desorption tower is controlled at 125℃, and the operating pressure at the top of the desorption tower is controlled at 25kPa. Under high temperature and negative pressure conditions, the dissolved and chemically combined hydrogen sulfide and carbon dioxide in the rich liquor are desorbed, discharged from the top of the desorption tower and collected as product gas.

[0063] Solution circulation: The lean solution flowing out from the bottom of the stripping tower is cooled to 50°C through heat exchange and then pumped back to the top of the absorption tower for reuse.

[0064] Comparative Examples 1-5:

[0065] Comparative Example 1:

[0066] Compared with Example 1, the difference lies in the formulation of the absorbent used in the dual-temperature zone hydrolysis and absorption steps. In Comparative Example 1, 40.0 kg of N-methyldiethanolamine was used to replace 25.0 kg of monopropanolamine and 15.0 kg of tripropanolamine in Preparation Example 1. The remaining components and amounts remained unchanged. That is, Comparative Example 1 used a mixed solution of sulfolane, N-methyldiethanolamine and water as the working medium. The remaining steps and parameters were the same as in Example 1.

[0067] Comparative Example 2:

[0068] Compared with Example 1, the difference lies in the formulation of the absorbent used in the dual-temperature zone hydrolysis and absorption steps. In Comparative Example 2, 15.0 kg of monopropanolamine was used instead of 15.0 kg of tripropanolamine in Preparation Example 1. That is, the absorbent in Comparative Example 2 was prepared from 45.0 kg of sulfolane, 40.0 kg of monopropanolamine and 15.0 kg of water, and did not contain tripropanolamine. The remaining steps and parameters were the same as in Example 1.

[0069] Comparative Example 3:

[0070] Compared with Example 1, the difference lies in the formulation of the absorbent used in the dual-temperature zone hydrolysis and absorption steps. In Comparative Example 3, 45.0 kg of water was used to replace 45.0 kg of sulfolane in Preparation Example 1. That is, Comparative Example 3 uses an aqueous solution composed of water, monopropanolamine and tripropanolamine as the working medium and does not contain the physical solvent sulfolane. The remaining steps and parameters are the same as in Example 1.

[0071] Comparative Example 4:

[0072] Compared with Example 1, the difference lies in the temperature control method in the dual-temperature zone hydrolysis and absorption steps. In Comparative Example 4, the absorption tower does not have two different temperature control zones. Instead, the liquid phase temperature of the entire absorption tower is uniformly controlled at 45°C. That is, in the dual-temperature zone hydrolysis and absorption steps, the bottom of the absorption tower is not heated, and the temperature of the upper and lower regions of the absorption tower is 45°C. The remaining steps and parameters are the same as in Example 1.

[0073] Comparative Example 5:

[0074] Compared with Example 1, the difference lies in the temperature control method in the dual-temperature zone hydrolysis and absorption steps. In Comparative Example 5, the absorption tower does not have two different temperature control zones. Instead, the liquid phase temperature of the entire absorption tower is uniformly controlled at 70°C. That is, in the dual-temperature zone hydrolysis and absorption steps, the absorbent is sprayed into the absorption tower at a temperature of 70°C. There is no interstage cooler in the middle of the absorption tower. The temperature of the upper and lower regions of the absorption tower is 70°C. The remaining steps and parameters are the same as in Example 1.

[0075] Test Example 1-2:

[0076] Test Example 1: Feasibility of the Invention and Product Verification

[0077] To verify the stability, conversion efficiency, and product recovery capability of the method for converting and recovering carbonyl sulfur-containing waste gas using a dual-temperature zone coupling process proposed in this invention during long-term operation, an experimental device was built based on the process conditions and equipment described in Example 1, and continuous dynamic testing was conducted.

[0078] Experimental steps and methods:

[0079] Start-up and stabilization of the device: The dual-temperature zone coupled process device was started according to the parameters and conditions described in Example 1, including setting the temperature of the lower region of the absorption tower to 70°C, the temperature of the upper region of the absorption tower to 45°C, and the reboiling temperature of the desorption tower to 135°C. Simulated carbonyl sulfur-containing waste gas was continuously introduced and the device was run continuously for 12 hours to eliminate the influence of the dead volume of the system and ensure that the fluid dynamics and thermodynamic distribution in the device reached a steady state of gas-liquid equilibrium.

[0080] Sampling Points: Three key online monitoring points are set up in the process flow. Monitoring point A is set at the inlet of the absorption tower to analyze the composition of the raw gas; monitoring point B is set at the top exhaust port of the absorption tower to analyze the composition of the purified gas; monitoring point C is set at the top exhaust port of the desorption tower (after condensation and water removal) to analyze the composition of the recovered product.

[0081] Analysis and detection: The gas components at the above monitoring points were analyzed using an online gas chromatograph equipped with a flame photometric detector (FPD) and a thermal conductivity detector (TCD). The FPD was used to detect trace amounts of hydrogen sulfide, carbonyl sulfide, and carbon disulfide; the TCD was used to detect high concentrations of carbon dioxide and hydrogen sulfide.

[0082] Data recording: The device was kept running continuously for 72 hours, and the component concentration data of each monitoring point was recorded every 12 hours to examine the process's resistance to fluctuations and long-term operational stability.

[0083] Experimental data: The experimental data are recorded in Table 1.

[0084] Table 1. Data Recording Table for Continuous Operation Monitoring of Dual-Temperature Zone Coupling Process

[0085] Running time (h) Monitoring point A: Intake air carbon disulfide concentration (ppm) Monitoring point A: Inlet air carbonyl sulfide concentration (ppm) Monitoring Point B: Exhaust hydrogen sulfide concentration (ppm) Monitoring point B: Exhaust carbon disulfide concentration (ppm) Monitoring Point B: Exhaust carbonyl sulfide concentration (ppm) Monitoring point C: Hydrogen sulfide content in the product gas (vol%) Monitoring point C: Carbon dioxide content in the product gas (vol%) 12 1985.4 1002.3 4.21 Not detected Not detected 64.23 35.41 24 2013.1 995.8 5.08 0.85 Not detected 63.89 35.82 36 1991.7 1008.4 3.65 Not detected Not detected 64.55 35.12 48 2005.6 998.2 4.92 Not detected 0.42 64.12 35.58 60 2021.0 1005.1 5.34 1.12 Not detected 63.78 35.94 72 1989.5 1001.7 4.56 Not detected Not detected 64.36 35.29

[0086] Note: "Not detected" means the concentration is below the detection limit of the gas chromatograph (0.1 ppm); vol% means volume percentage.

[0087] Conclusion and Analysis: Based on the test data in Table 1 and the process parameters of Example 1, the effectiveness of the technical solution of the present invention is analyzed as follows:

[0088] First, data from monitoring point B (the exhaust port of the absorption tower) showed that under continuous impact from high concentrations of organic sulfur (approximately 2000 ppm carbon disulfide and 1000 ppm carbonyl sulfur), the residual carbon disulfide and carbonyl sulfur in the purified gas remained at "undetectable" or extremely low concentrations (<2 ppm) for a long period, indicating that the hydrolysis conversion rate of organic sulfur was close to 100%. This confirms that the highly active primary amine structure of monopropanolamine in the high-temperature zone (70°C) at the bottom of the absorption tower overcomes the defects of the hydrolysis reaction of carbon disulfide and carbonyl sulfur, enabling organic sulfur to be rapidly converted into inorganic sulfur upon contact.

[0089] Secondly, the concentration of hydrogen sulfide at monitoring point B remained below 6 ppm. Even with the large-scale conversion of organic sulfur into hydrogen sulfide leading to a surge in sulfur load within the tower, the hydrogen sulfide escape rate remained extremely low. This is attributed to the design of the low-temperature zone (45°C) at the top of the absorption tower. The low-temperature environment significantly improved the thermodynamic equilibrium solubility of hydrogen sulfide in tripropanolamine, thereby enabling secondary interception of the hydrogen sulfide generated in the lower reaction zone.

[0090] Finally, the data from monitoring point C (the product of the stripping tower) showed that the main components of the recovered gas were high concentrations of hydrogen sulfide (approximately 64 vol%) and carbon dioxide (approximately 35 vol%), confirming that carbon disulfide and carbonyl sulfur did not undergo through emission, but rather underwent chemical structural transformation and were ultimately enriched and recovered through the pressure swing thermal desorption process.

[0091] In summary, this invention, through the combination of monopropanolamine and tripropanolamine and the synergistic effect of sulfolane medium, combined with the construction of a dual-temperature gradient within the absorption tower, successfully achieved the simultaneous deep hydrolysis of organic sulfur and efficient absorption of the products within a single tower device, verifying the feasibility of this technical solution in the resource-based treatment of industrial waste gas.

[0092] Test Example 2: Comparison Test of Conversion Efficiency and Purification Effect

[0093] To investigate the specific effects of different absorbent formulations and different process temperature control strategies on the treatment performance of carbonyl sulfur-containing waste gas, Examples 1 to 3 and Comparative Examples 1 to 5 were selected as test subjects and parallel comparative experiments were conducted under the same inlet load conditions.

[0094] Experimental steps and methods:

[0095] Experimental conditions were uniform: all experiments used the same simulated waste gas source, and the concentration of carbon disulfide at the inlet of the absorption tower was controlled at 2000 ppm, the concentration of carbonyl sulfide at 1000 ppm, and the concentration of carbon dioxide at 5.0%, while the gas flow rate was kept constant.

[0096] Independent operation test: The experimental device was run according to the absorbent formulation and process control parameters (including temperature, pressure, liquid-gas ratio, etc. in each region) as described in Examples 1 to 3 and Comparative Examples 1 to 5.

[0097] Steady-state sampling: Each experimental setup was run continuously for 48 hours. After the system reached a thermodynamically stable state, gas samples were collected from the exhaust port at the top of the absorption tower.

[0098] Index Calculation: The concentrations of carbon disulfide, carbonyl sulfide, and hydrogen sulfide in the exhaust gas are analyzed by gas chromatography. The hydrolysis conversion rates of carbon disulfide and carbonyl sulfide are calculated based on the inlet and outlet concentrations.

[0099] Calculation formula: Carbon disulfide hydrolysis conversion rate = (1 - Carbon disulfide concentration at the absorber outlet / Carbon disulfide concentration at the absorber inlet) × 100%.

[0100] Experimental data: The specific data obtained in the experiment are recorded in Table 2.

[0101] Table 2. Comparison of treatment effects under different formulations and processes

[0102] Test object Carbon disulfide hydrolysis conversion rate (%) Carbonyl sulfide hydrolysis conversion rate (%) Hydrogen sulfide concentration in the exhaust gas from the absorption tower (ppm) Overall assessment notes Example 1 99.92 99.95 4.23 All indicators are balanced Example 2 99.85 99.89 5.67 High pressure is beneficial for absorption Example 3 99.96 99.98 3.81 High water content increases reaction rate Comparative Example 1 42.15 55.32 1.05 Organic sulfur penetrates in large quantities Comparative Example 2 99.88 99.91 86.42 Significant hydrogen sulfide escape Comparative Example 3 68.45 74.21 8.12 Incomplete conversion of organic sulfur Comparative Example 4 58.73 66.09 0.89 Low temperature inhibits hydrolysis reaction Comparative Example 5 99.94 99.96 325.18 High temperature causes desorption escape

[0103] Conclusion Analysis: Based on the test data in Table 2, the impact of different variables on process performance is analyzed as follows:

[0104] First, regarding the selection of amine components, comparing the data of Example 1 and Comparative Example 1, Example 1 used monopropanolamine as the active component, and its carbon disulfide hydrolysis conversion rate reached 99.92%, while Comparative Example 1 used N-methyldiethanolamine, and the carbon disulfide hydrolysis conversion rate was only 42.15%. The data shows that although conventional tertiary amines (N-methyldiethanolamine) have the ability to absorb acidic gases (low concentration of hydrogen sulfide in exhaust gas), their catalytic activity for the hydrolysis reaction of carbonyl sulfide and carbon disulfide is much lower than that of monopropanolamine, which has a primary amine structure.

[0105] Second, regarding the synergistic effect of the compound components, comparing the data of Example 1 and Comparative Example 2, Comparative Example 2 used only monopropanolamine without adding tripropanolamine. Although it maintained a high organic sulfur hydrolysis conversion rate (99.88%), the hydrogen sulfide concentration in the exhaust gas of the absorption tower increased to 86.42 ppm. This confirms that although monopropanolamine has high reactivity, as a primary amine, it has limitations in desorption and regeneration performance and sulfur balance capacity. Introducing tripropanolamine as a tertiary amine component can effectively supplement the absorption capacity of the solution and inhibit the escape of hydrogen sulfide.

[0106] Third, regarding the role of physical solvents, comparing the data from Example 1 and Comparative Example 3, the carbon disulfide hydrolysis conversion rate decreased to 68.45% after removing sulfolane in Comparative Example 3. This indicates that sulfolane, as a physical solvent, can significantly increase the solubility of hydrophobic organic sulfur molecules in the liquid phase, thereby increasing the concentration of reactants in the liquid phase and promoting the hydrolysis reaction.

[0107] Fourth, regarding the necessity of the dual-temperature zone process, comparing the data from Example 1 and Comparative Example 4 (all low temperature 45°C), the carbon disulfide hydrolysis conversion rate in Comparative Example 4 decreased significantly to 58.73%. This indicates that under low temperature conditions, the kinetic rate of the organic sulfur hydrolysis reaction is limited, and the conversion cannot be completed in a short time during gas-liquid contact, verifying the necessity of setting up a high-temperature hydrolysis zone at the bottom of the absorber. Comparing the data from Example 1 and Comparative Example 5 (all high temperature 70°C), although Comparative Example 5 achieved an extremely high carbon disulfide hydrolysis conversion rate (99.94%), the hydrogen sulfide concentration in the absorber exhaust gas surged to 325.18 ppm, indicating that under high temperature conditions, the gas-liquid equilibrium shifts towards the gas phase, resulting in the generated hydrogen sulfide not being effectively retained by the solution.

[0108] In summary, Examples 1 to 3, by employing a specific ratio of sulfolane, monopropanolamine, and tripropanolamine, and combining it with a dual-temperature zone coupling process of high-temperature hydrolysis at the bottom and low-temperature absorption at the top of the absorption tower, resolved the thermodynamic contradiction between the hydrolysis rate of organic sulfur and the absorption equilibrium of the product hydrogen sulfide, thus achieving efficient purification and resource conversion of carbonyl sulfur-containing waste gas.

Claims

1. A method for preparing a carbonyl sulfur hydrolysis catalyst, characterized in that, Includes the following steps: Under mechanical stirring, water, sulfolane, monopropanolamine, and tripropanolamine are added sequentially to the mixing vessel; the weight parts of sulfolane are 30.0-60.0; the weight parts of monopropanolamine are 20.0-30.0; the weight parts of tripropanolamine are 10.0-20.0; and the weight parts of water are 10.0-20.

0. Control the temperature inside the mixing vessel to 20℃-30℃, and continue stirring until sulfolane, monopropanolamine, tripropanolamine and water are completely miscible to form a homogeneous transparent liquid; A homogeneous transparent liquid was filtered through a filter element with a pore size of 3μm-7μm to obtain a carbonyl sulfur hydrolysis catalyst.

2. The application of a carbonyl sulfur hydrolysis catalyst, characterized in that, The carbonyl sulfur hydrolysis catalyst prepared by the method described in claim 1 comprises the following steps: S1. The gas containing carbonyl sulfide, carbon disulfide and carbon dioxide is heated and then introduced into the bottom of the absorption tower; S2. The carbonyl sulfide hydrolysis catalyst is sprayed into the absorption tower from the top as the absorbent. Two different temperature control zones are constructed inside the absorption tower. The lower zone of the absorption tower is the hydrolysis reaction zone, and the liquid phase temperature in the lower zone is maintained higher than the gas-liquid contact temperature in the upper zone. In the lower zone, monopropanolamine in the carbonyl sulfide hydrolysis catalyst catalyzes the hydrolysis of carbon disulfide and carbonyl sulfide to produce hydrogen sulfide and carbon dioxide. At the same time, in the upper zone, tripropanolamine in the carbonyl sulfide hydrolysis catalyst absorbs hydrogen sulfide and carbon dioxide. S3. The rich liquid that has absorbed hydrogen sulfide and carbon dioxide discharged from the bottom of the absorption tower is transported to the desorption tower, where hydrogen sulfide and carbon dioxide are desorbed as product gas under high temperature and negative pressure conditions. S4. The lean liquid flowing from the bottom of the analytical column is cooled and then sent back to the top of the absorption column for recycling.

3. The application of the carbonyl sulfur hydrolysis catalyst according to claim 2, characterized in that, In step S2, the liquid phase temperature in the lower region of the absorption tower is controlled at 60℃-75℃; the gas-liquid contact temperature in the upper region of the absorption tower is controlled at 40℃-50℃.

4. The application of the carbonyl sulfur hydrolysis catalyst according to claim 2, characterized in that, In step S2, the temperature of the rising gas flow and the flowing liquid is cooled by an interstage cooler located in the middle of the absorption tower to maintain the gas-liquid contact temperature in the upper region of the absorption tower; the liquid phase temperature in the lower region of the absorption tower is maintained by the tower bottom heating and reaction heat.

5. The application of the carbonyl sulfur hydrolysis catalyst according to claim 2, characterized in that, In step S2, the liquid-to-gas ratio of the carbonyl sulfide hydrolysis catalyst to the gas containing carbonyl sulfide and carbon disulfide is controlled to be 2.0 L / m³. 3 -5.0L / m 3 The operating pressure of the absorption tower is controlled between 1.2 bar and 4.0 bar.

6. The application of the carbonyl sulfur hydrolysis catalyst according to claim 2, characterized in that, In step S2, the temperature of the carbonyl sulfur hydrolysis catalyst sprayed into the absorption tower from the top is controlled at 40℃-50℃.

7. The application of the carbonyl sulfur hydrolysis catalyst according to claim 2, characterized in that, In step S3, the temperature at the bottom of the analytical column is controlled at 125℃-145℃, and the pressure at the top of the analytical column is controlled at 10kPa-25kPa.

8. The application of the carbonyl sulfur hydrolysis catalyst according to claim 2, characterized in that, In step S1, the gas containing carbonyl sulfide and carbon disulfide is heated to 50°C-80°C and then introduced into the bottom of the absorption tower.

9. The application of the carbonyl sulfur hydrolysis catalyst according to claim 2, characterized in that, In step S4, the lean liquid flowing out from the bottom of the desorption tower is cooled to 40°C-50°C and then transported back to the top of the absorption tower for recycling.