A method and apparatus for carbonyl sulfide removal

Abstract

The application provides a carbonyl sulfur removal method and a carbonyl sulfur removal device. A complex promoter is introduced in the carbonyl sulfur removal process, and the complex promoter comprises a main promoter and an auxiliary promoter. The main promoter comprises a quaternary ammonium salt compound and / or a cyclic ether compound, and the auxiliary promoter comprises a sulfonate surfactant and / or a glycoside surfactant. The application can realize efficient and selective removal of carbonyl sulfur under the conditions of near normal temperature (1-21 DEG C) and low pressure (0.1-6.0 MPa), can improve the removal rate, reduce the loss of effective gas, eliminate secondary pollution, and can meet the actual needs of industrial continuous operation.

Description

Technical Field

[0001] This invention belongs to the field of synthesis gas purification and gas carbonyl sulfide removal technology, specifically relating to a carbonyl sulfide removal method and a carbonyl sulfide removal device. Background Technology

[0002] Coal-derived syngas and biomass syngas are important industrial feedstock gases, with hydrogen and carbon monoxide as their main active components. They can be used to synthesize high-value-added products such as methanol, ammonia, and Fischer-Tropsch oils, and are also important sources of hydrogen production. During coal gasification and biomass gasification, sulfur in the feedstock is converted into carbonyl sulfide. Carbonyl sulfide is corrosive and toxic, not only corroding downstream process pipelines and reaction equipment but also causing poisoning and deactivation of the syngas conversion catalyst. Furthermore, its emission causes severe air pollution. Therefore, efficient removal of carbonyl sulfide is an essential purification step before syngas utilization.

[0003] Currently, industrial carbonyl sulfide removal technologies for syngas are mainly divided into two categories: dry carbonyl sulfide removal and wet carbonyl sulfide removal. Dry carbonyl sulfide removal mostly uses solid carbonyl sulfide removal agents such as zinc oxide and iron oxide. It has high carbonyl sulfide removal precision, but the carbonyl sulfide removal agents are non-renewable or difficult to regenerate, and a large amount of solid hazardous waste is generated after use, resulting in high treatment costs. It is only suitable for deep removal of low-concentration carbonyl sulfide. Wet carbonyl sulfide removal, represented by the alkanolamine method, is currently the mainstream carbonyl sulfide removal process. It absorbs carbonyl sulfide through alkanolamine solution. The absorbent is regenerable, but it has problems such as large absorbent degradation losses, high regeneration energy consumption, easy equipment corrosion, solution foaming, and secondary pollution caused by sulfur-containing waste liquid. Moreover, for high-sulfur syngas, energy consumption and operating costs remain high.

[0004] Gas hydrate separation technology is a novel, mild gas separation technique that utilizes the differences in phase equilibrium conditions for hydrate formation among different gas components to achieve selective separation. Carbonyl sulfide, compared to hydrogen and carbon monoxide, readily forms gaseous hydrates under mild conditions, a characteristic that can be leveraged for efficient separation of carbonyl sulfide from syngas components. However, traditional hydrate methods have significant drawbacks: relying solely on spontaneous hydrate formation requires high pressure and low temperature conditions, typically exceeding 5 MPa, resulting in high energy consumption and stringent requirements for equipment pressure resistance and low-temperature compatibility; hydrate nucleation induction time is long, and crystallization rate is slow, making it unsuitable for continuous industrial production; furthermore, the selectivity of hydrate separation is poor, easily leading to the entrainment of some effective syngas with the hydrates, significantly reducing syngas recovery and utilization rates.

[0005] Existing hydrate-based carbonyl sulfide removal technologies generally suffer from problems such as demanding phase equilibrium conditions, low separation efficiency, and difficulties in continuous operation, failing to meet the practical application requirements of industrial-scale carbonyl sulfide removal in coal-to-syngas and biomass syngas. Therefore, developing a hydrate-based carbonyl sulfide removal technology that can operate under near-ambient temperature and medium-low pressure conditions, while possessing high selectivity, low energy consumption, and no secondary pollution, is of significant practical importance for overcoming the bottlenecks in existing syngas carbonyl sulfide removal processes and promoting the green development of the coal chemical and biomass energy industries. Summary of the Invention

[0006] This invention provides a carbonyl sulfide removal method and a carbonyl sulfide removal device. By introducing a compound accelerator, the formation pressure of carbonyl sulfide hydrate can be significantly reduced and the formation rate can be significantly increased, thereby achieving efficient and selective separation of carbonyl sulfide at near room temperature and medium-low pressure. This method can ensure the carbonyl sulfide removal accuracy and effective gas recovery rate, achieve low energy consumption operation, and produce no secondary pollution throughout the process, making it suitable for industrial continuous production needs.

[0007] This invention provides a method for removing carbonyl sulfide, comprising the following steps: S1, passing a carbonyl sulfide-containing raw material gas into an aqueous solution containing a compound accelerator, and carrying out a hydration reaction at 1~21℃ and 0.1MPa~6.0MPa, whereby carbonyl sulfide and water are converted into carbonyl sulfide hydrates, forming a gas-liquid-solid coexistence system; this system includes a slurry containing carbonyl sulfide hydrates and purified gas after carbonyl sulfide removal; S2, performing gas-liquid separation on the gas-liquid-solid coexistence system to obtain purified gas after carbonyl sulfide removal and a slurry containing carbonyl sulfide hydrates; the compound accelerator includes a main accelerator and a co-accelerator, the main accelerator including quaternary ammonium salt compounds and / or cyclic ether compounds, and the co-accelerator including sulfonate surfactants and / or glycoside surfactants.

[0008] In the carbonyl sulfide removal method described above, the gas-liquid volume ratio of the carbonyl sulfide-containing feed gas and the aqueous solution containing the compound accelerator at standard conditions of 273.15 K, 101.325 kPa is (5~500):1; and / or, the mass percentage content of the compound accelerator in the aqueous solution containing the compound accelerator is 6%-30%.

[0009] In the carbonyl sulfide removal method described above, the mass ratio of the main promoter to the co-promoter is (200~3000):1.

[0010] In the carbonyl sulfide removal method described above, the quaternary ammonium salt compound includes tetrabutylammonium bromide and / or tetrabutylammonium chloride; and / or, the cyclic ether compound includes tetrahydrofuran and / or tetrahydropyran; and / or, the sulfonate surfactant includes sodium dodecyl sulfate and / or sodium dodecylbenzenesulfonate; and / or, the glycoside surfactant includes glucosinolate surfactant and / or glucosinolate surfactant; and / or, in step S1, the residence time of the carbonyl sulfide-containing feed gas in the aqueous solution containing the compounded accelerator is 10 s to 15 min.

[0011] The carbonyl sulfide removal method described above, wherein the preparation process of the carbonyl sulfide-containing feed gas in step S1 includes: cooling the carbonyl sulfide-containing crude feed gas to 1-21°C to obtain the carbonyl sulfide-containing feed gas.

[0012] The carbonyl sulfide removal method described above further includes, after step S2: decomposing the liquid material containing carbonyl sulfide hydrate to obtain carbonyl sulfide-rich gas and a dissociated compound accelerator; returning the aqueous solution of the dissociated compound accelerator to the aqueous solution containing the compound accelerator for recycling; and enriching and recovering the carbonyl sulfide gas.

[0013] In the carbonyl sulfide removal method described above, the decomposition process is carried out at a temperature of 25-45°C and a pressure of 0.1-6.0 MPa.

[0014] The present invention also provides a carbonyl sulfide removal apparatus for the above-described carbonyl sulfide removal method, comprising a hydration unit and a separation unit connected in sequence.

[0015] The carbonyl sulfide removal device described above, wherein the hydration unit includes a high-pressure reactor or a tubular reactor; preferably, the high-pressure reactor is equipped with a stirring device and a spraying device; and / or, the separation unit includes a sedimentation separator or a centrifugal separator.

[0016] The carbonyl sulfide removal device as described above includes a hydration unit with an inlet for raw material gas and an inlet for an aqueous solution containing a compound accelerator, and an outlet for a gas-liquid mixture; a separation unit with an inlet for a gas-liquid mixture, a purified gas outlet, and an outlet for a liquid phase material containing carbonyl sulfide hydrates, all connected to the outlet for the gas-liquid mixture of the hydration unit; the carbonyl sulfide removal device further includes a pretreatment unit, a decomposition unit, and a circulation unit; the pretreatment unit has a crude raw material gas inlet and a raw material gas outlet; the raw material gas outlet of the pretreatment unit is connected to the raw material gas inlet of the hydration unit; the decomposition unit has an inlet for a liquid phase material containing carbonyl sulfide hydrates, a carbonyl sulfide gas outlet, and a dissociated liquid phase material outlet, all connected to the outlet for the liquid phase material containing carbonyl sulfide hydrates of the separation unit; the circulation unit includes a dissociated liquid phase material inlet and a circulating liquid phase material outlet; the dissociated liquid phase material inlet of the circulation unit is connected to the dissociated liquid phase material outlet of the decomposition unit; and the circulating liquid phase material outlet of the circulation unit is connected to the hydration unit.

[0017] This invention provides a method and apparatus for removing carbonyl sulfide. A compound accelerator is introduced into the carbonyl sulfide removal process, comprising a primary accelerator and a secondary accelerator. The primary accelerator includes quaternary ammonium salts and / or cyclic ethers, while the secondary accelerator includes sulfonate surfactants and / or glycoside surfactants. This invention achieves highly efficient and selective separation of carbonyl sulfide under near-ambient temperature (1~21℃) and medium-low pressure (0.1~6.0MPa) conditions, offering advantages such as fast reaction rate, low effective gas loss, and no secondary pollution, meeting the practical requirements of continuous industrial operation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process flow for removing carbonyl sulfur from the feed gas containing carbonyl sulfur in an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] This invention provides a method for removing carbonyl sulfide, comprising the following steps: S1, passing a carbonyl sulfide-containing feed gas into an aqueous solution containing a compound accelerator, and carrying out a hydration reaction under conditions of 1~21℃ (e.g., 1℃, 5℃, 10℃, 15℃, or 21℃, etc.) and 0.1MPa~6.0MPa (e.g., 0.1MPa, 0.5MPa, 1MPa, 2MPa, 3MPa, 4MPa, 5MPa, or 6.0MPa, etc.), whereby carbonyl sulfide and water are converted into carbonyl. Carbonyl sulfide hydrate forms a gas-liquid-solid coexistence system; the gas-liquid-solid coexistence system includes a slurry containing carbonyl sulfide hydrate and a purified gas after carbonyl sulfide removal; S2, the gas-liquid-solid coexistence system is subjected to gas-liquid separation to obtain a purified gas after carbonyl sulfide removal and a slurry containing carbonyl sulfide hydrate; the compound accelerator includes a main accelerator and a co-accelerator, the main accelerator includes quaternary ammonium salt compounds and / or cyclic ether compounds, and the co-accelerator includes sulfonate surfactants and / or glycoside surfactants.

[0021] In this embodiment of the invention, in the gas-liquid-solid coexistence system, the purified gas after the removal of carbonyl sulfide and the slurry containing carbonyl sulfide hydrate are in a phase equilibrium state.

[0022] This invention employs a compounded promoter in the carbonyl sulfide removal process, enabling highly efficient and selective separation of carbonyl sulfide under near-ambient temperature (1~21℃) and medium-low pressure (0.1~6.0MPa) conditions. It combines the advantages of fast reaction rate, low effective gas loss, and no secondary pollution, meeting the practical needs of continuous industrial operation. Specifically, water molecules in the aqueous solution construct a cage-like lattice and capture carbonyl sulfide in the feed gas through physical inclusion, generating carbonyl sulfide hydrates. The main promoter, through its molecular structure characteristics, enters the cage-like structure of the hydrate, reducing the pressure required for carbonyl sulfide hydrate formation and increasing the formation temperature, thus adapting the reaction conditions to a near-ambient temperature and medium-low pressure environment. The co-promoter accelerates the diffusion of carbonyl sulfide molecules into the hydrate formation region by reducing the gas-liquid interfacial tension, while simultaneously enhancing the selective adsorption of carbonyl sulfide through intermolecular forces, reducing the entrainment loss of effective gases (hydrogen, carbon monoxide). Furthermore, this compound accelerator exhibits excellent thermal stability and cycling performance, maintaining high-efficiency removal capability after multiple uses without frequent replacement, thus enabling low-carbon and environmentally friendly continuous operation. Therefore, this invention can achieve highly efficient and selective separation of carbonyl sulfide under near-ambient temperature (1-21℃) and medium-low pressure (0.1-6.0MPa) conditions, while simultaneously increasing the reaction rate, reducing effective gas loss, and eliminating secondary pollution, thus meeting the requirements of industrial continuous operation.

[0023] In this embodiment of the invention, the carbonyl sulfide-containing feed gas includes coal-based syngas or biomass syngas containing carbonyl sulfide. After treatment using the carbonyl sulfide removal method of the present invention, excellent removal and effective gas recovery effects can be achieved: the carbonyl sulfide removal rate in the carbonyl sulfide-containing feed gas is ≥99%, the carbonyl sulfide content in the purified gas is ≤2ppm, and the total recovery rate of hydrogen and carbon monoxide is ≥98.0%.

[0024] In this embodiment of the invention, the gas-liquid volume ratio of the carbonyl sulfide-containing feed gas and the aqueous solution containing the compounded accelerator is (5~500):1 under standard conditions of 273.15 K, 101.325 kPa. This is beneficial for balancing the mass transfer rate and the reaction residence time, ensuring sufficient contact between the carbonyl sulfide and the accelerator, thus meeting the needs of continuous industrial production.

[0025] For example, the gas-liquid volume ratio of the carbonyl sulfide-containing feed gas and the aqueous solution containing the compound accelerator can be 5:1, 10:1, 20:1, 30:1, 40:1, 100:1, 150:1, 200:1, 250:1, 300:1, 350:1, 400:1, 450:1 or 500:1, etc.

[0026] In this embodiment of the invention, the gas-liquid volume ratio of the carbonyl sulfide-containing feed gas and the gas-liquid ratio containing the compound accelerator refers to the ratio between the volume of the carbonyl sulfide-containing feed gas per unit volume and the volume of the corresponding aqueous solution containing the compound accelerator participating in the reaction under standard conditions (273.15K, 0.1013MPa).

[0027] In this embodiment of the invention, the mass percentage of the compound accelerator in the aqueous solution containing the compound accelerator is 6% to 30%. This helps to better ensure the stability of carbonyl sulfide removal efficiency, reduce process costs, improve operational stability, adapt to the needs of continuous industrial operation, and avoid equipment wear and secondary pollution.

[0028] For example, the mass percentage of the compound accelerator in the aqueous solution containing the compound accelerator can be 6%, 8%, 10%, 13%, 18%, 22%, 25%, 28%, or 30%, etc.

[0029] In some embodiments, the mass ratio of the main promoter to the co-promoter is (200~300):1. This allows the main promoter to fully exert its core role in regulating hydrate phase equilibrium and optimizing the cage structure, while a small amount of co-promoter can effectively reduce gas-liquid interfacial tension and enhance the selective adsorption and mass transfer diffusion of carbonyl sulfide, thus achieving better synergistic effects.

[0030] For example, the mass ratio of the main accelerator to the co-accelerator can be 200:1, 210:1, 220:1, 230:1, 240:1, 250:1, 260:1, 270:1, 280:1, 290:1 or 300:1, etc.

[0031] In some embodiments, the quaternary ammonium salt compound includes tetrabutylammonium bromide and / or tetrabutylammonium chloride. Tetrabutylammonium bromide and tetrabutylammonium chloride have large cations and stable molecular structures, making them easy to insert into and regularly construct hydrate cage-like crystal lattices. They can significantly reduce the formation pressure of carbonyl sulfide hydrates, increase the nucleation temperature, and are suitable for near-room temperature, low pressure, and moderate operating conditions. Simultaneously, they enhance the thermal and mechanical stability of the hydrate crystal framework, shorten the nucleation induction time, accelerate the crystallization rate, reduce the entrainment loss of effective syngas components such as hydrogen and carbon monoxide, and improve the syngas recovery rate.

[0032] In some embodiments, the cyclic ether compounds include tetrahydrofuran and / or tetrahydropyran. Tetrahydrofuran and tetrahydropyran are miscible with water molecules and can serve as excellent thermodynamic promoters for hydrates, inducing rapid nucleation and growth of hydrates; they can effectively broaden the temperature and pressure range for the stable existence of carbonyl sulfur hydrates, weaken the harsh high-pressure and low-temperature requirements, and reduce process energy consumption and equipment pressure resistance and low-temperature configuration requirements; moreover, they are chemically mild, do not produce by-products, are non-corrosive, and are suitable for long-term cyclic use in the system.

[0033] In some embodiments, the sulfonate surfactants include sodium dodecyl sulfate and / or sodium dodecylbenzene sulfonate. Sodium dodecyl sulfate and sodium dodecylbenzene sulfonate can significantly reduce the gas-liquid interfacial tension, decrease mass transfer resistance, and accelerate the diffusion and migration of carbonyl sulfide molecules to the hydrate formation interface; at the same time, they have excellent interfacial adsorption selectivity, which can preferentially enrich the carbonyl sulfide component, further improving the efficient and selective separation of carbonyl sulfide; and, sodium dodecyl sulfate and sodium dodecylbenzene sulfonate require small amounts, have good compatibility, and are suitable for stable operation in continuous chemical industries.

[0034] In some embodiments, glycoside surface promoters include glucosinolate surfactants and / or glucosinolate surfactants. Glucoside surfactants and glucosinolate surfactants can significantly reduce gas-liquid interfacial tension, decrease mass transfer resistance, and accelerate the diffusion and migration of carbonyl sulfide molecules to the hydrate formation interface; thus, they are suitable for stable operation in continuous chemical industries.

[0035] In some embodiments, in step S1, the residence time of the carbonyl sulfide-containing feed gas in the aqueous solution containing the compounded accelerator is 10s to 15min. This facilitates sufficient gas-liquid contact between the carbonyl sulfide and the accelerator aqueous solution, completing the hydrate formation reaction and achieving a high removal rate.

[0036] For example, the residence time of the carbonyl sulfide-containing feed gas in an aqueous solution containing a compound accelerator can be 10 s, 1 min, 3 min, 5 min, 7 min, 9 min, 11 min, 13 min, or 15 min, etc.

[0037] In this embodiment of the invention, step S1, the preparation process of the carbonyl sulfide-containing feed gas, includes: cooling the crude carbonyl sulfide-containing feed gas to 1-21°C to obtain the carbonyl sulfide-containing feed gas. Cooling to 1-21°C means adjusting the gas temperature to a suitable temperature range for hydrate formation using a heat exchanger, cooler, or condenser, so that the feed gas has more stable thermodynamic conditions before entering the aqueous solution containing the compounded promoter, and reduces the additional refrigeration load in subsequent reactions.

[0038] In some embodiments, step S2 is followed by: decomposing the liquid phase material containing carbonyl sulfide hydrate to obtain carbonyl sulfide gas and a dissociated compound accelerator; returning the dissociated compound accelerator to the aqueous solution containing the compound accelerator for recycling; and enriching and recovering the carbonyl sulfide gas. Specifically, the liquid phase material containing carbonyl sulfide hydrate after gas-liquid separation is continuously or intermittently fed into the decomposition unit. Under heating or reduced pressure, the liquid phase material gradually destroys the hydrate crystal structure, and carbonyl sulfide changes from an inclusion state to a free gaseous state and precipitates from the liquid phase, forming carbonyl sulfide gas with a significantly increased concentration. At the same time, the compound accelerator that originally participated in hydrate formation dissociates from the crystal and re-enters the recyclable state with the liquid phase. The dissociated compound accelerator is cooled, filtered, and returned to the aqueous solution system containing the compound accelerator, so that it can continue to participate in the formation of carbonyl sulfide hydrate when the next round of feed gas is introduced, thereby reducing accelerator consumption and waste liquid discharge. The carbonyl sulfur gas is then introduced into a subsequent enrichment and recovery unit for centralized collection, compression storage, or further purification and recovery, thereby realizing the resource utilization of sulfur-containing components.

[0039] In some implementations, the decomposition process is carried out at a temperature of 25-45°C and a pressure of 0.1-6.0 MPa. This facilitates the transformation of the generated carbonyl sulfide hydrate from a stable formation state to a thermodynamically unstable state, providing sufficient driving force for the dissociation of the hydrate lattice. Simultaneously, it avoids problems such as the loss of thermodynamic promoters caused by excessively high temperatures or sudden pressure drops, effectively improving the continuity of carbonyl sulfide desorption and release, as well as the stability and controllability of the entire recovery process.

[0040] The present invention also provides a carbonyl sulfide removal apparatus for performing the above-described carbonyl sulfide removal method, comprising a hydration unit and a separation unit connected in sequence.

[0041] In some implementations, the hydration unit includes a high-pressure reactor or a tubular reactor.

[0042] In some embodiments, the high-pressure reactor is equipped with a stirring device and a spraying device.

[0043] In some implementations, the high-pressure reactor and tubular reactor are equipped with external temperature control jackets. These jackets enable precise temperature control within a range of 1-21°C, strictly matching the near-ambient temperature conditions required for the hydration reaction, ensuring the efficient and stable formation of carbonyl sulfide hydrates. The overall pressure rating of the device matches the operating pressure of the upstream process, or can be appropriately reduced according to actual operating conditions, meeting the operational requirements of medium and low pressure (0.1~6.0MPa) while reducing equipment manufacturing costs. Simultaneously, an online carbonyl sulfide monitoring probe is installed at the purified gas outlet, enabling real-time detection of the carbonyl sulfide content in the purified gas. This allows for real-time monitoring of the carbonyl sulfide removal effect, facilitating timely adjustment of process parameters and ensuring that the purified gas indicators meet standards.

[0044] In some embodiments, the separation unit includes a sedimentation separator or a centrifugal separator, which facilitates the efficient separation of purified gas and liquid phase material containing carbonyl sulfide hydrate.

[0045] In this embodiment of the invention, the hydration unit is provided with a raw material gas inlet and a gas-liquid mixture outlet; the separation unit is provided with a gas-liquid mixture inlet, a purified gas outlet, and a liquid phase material outlet containing carbonyl sulfur hydrate, all connected to the gas-liquid mixture outlet of the hydration unit; the carbonyl sulfur removal device further includes a pretreatment unit, a decomposition unit, and a circulation unit; the pretreatment unit is provided with a crude raw material gas inlet and a raw material gas outlet; the raw material gas outlet of the pretreatment unit is connected to the raw material gas inlet of the hydration unit; the decomposition unit is provided with a carbonyl sulfur hydrate liquid phase material inlet, a carbonyl sulfur gas outlet, and a dissociated liquid phase material outlet, all connected to the liquid phase material outlet containing carbonyl sulfur hydrate of the separation unit; the circulation unit includes a dissociated liquid phase material inlet and a circulating liquid phase material outlet; the dissociated liquid phase material inlet of the circulation unit is connected to the dissociated liquid phase material outlet of the decomposition unit; the circulating liquid phase material outlet of the circulation unit is connected to the hydration unit.

[0046] In some embodiments, the hydrate decomposition unit (i.e., the decomposition unit) can flexibly select either a high-pressure heating decomposition vessel or a low-pressure heating decomposition vessel according to the pressure requirements of subsequent carbonyl sulfide gas enrichment and recovery. Simultaneously, the hydrate decomposition unit is equipped with a gas output control device to precisely regulate the output flow rate and pressure of the decomposed carbonyl sulfide gas, ensuring a stable entry of the carbonyl sulfide gas into the subsequent enrichment and recovery unit, and guaranteeing the controllability of the entire desorption and recovery process. The hydrate working fluid circulation unit (i.e., the circulation unit) is equipped with a cooler and a delivery pump: the cooler cools the high-temperature accelerator aqueous solution discharged after dissociation in the decomposition unit to the temperature required for the hydration reaction (suitable for near-ambient temperature conditions of 1~21℃), preventing the high-temperature solution from entering the hydration unit and affecting the hydration reaction efficiency; the delivery pump provides power for the circulation of the accelerator aqueous solution, stably delivering the cooled dissociated accelerator aqueous solution to the hydration unit, realizing closed-loop recycling of the compound accelerator solution, reducing accelerator loss, and lowering process operating costs.

[0047] In this embodiment of the invention, the carbonyl sulfide removal device can achieve continuous operation throughout the entire process, with no solid waste generated and no secondary pollution during operation. The process does not consume chemical carbonyl sulfide removal agents, but only requires a small amount of energy for heating hydrate decomposition and cooling the circulation promoter solution. The overall operating cost is significantly lower than that of traditional alkanolamine and dry carbonyl sulfide removal processes, making it more suitable for the needs of large-scale continuous and stable industrial operation.

[0048] like Figure 1 As shown, the carbonyl sulfide removal process adopts a continuous process, specifically including the following steps: the raw gas containing carbonyl sulfide enters the hydrator through the first pressure and flow regulating valve and the first cooler, and fully contacts the compound accelerator solution. Under controlled temperature and pressure conditions, carbonyl sulfide-rich hydrates are rapidly generated and enter the aqueous phase to form a slurry containing carbonyl sulfide hydrates; the gas that does not form hydrates (mainly hydrogen and carbon monoxide) is retained in the gas phase. The slurry containing carbonyl sulfide hydrates and the gas phase are separated. The purified gas (mainly hydrogen and carbon monoxide) after carbonyl sulfide removal is directly transported to the subsequent process; the slurry containing carbonyl sulfide hydrates enters the hydrate decomposition tower through the second pressure and flow regulating valve and the heater, and is decomposed under low pressure and temperature heating to release high-concentration carbonyl sulfide gas. The decomposed compound accelerator is cooled and recycled, realizing a closed-loop material flow throughout the process with no waste liquid or residue discharge. The supporting equipment adopts a modular design, integrating five major functions: pretreatment, hydration, solid-gas separation, decomposition and regeneration, and circulation. It has a compact structure, is easy to operate, and can achieve continuous automated operation, adapting to carbonyl sulfur removal conditions of coal-to-syngas and biomass syngas of different scales.

[0049] Example 1

[0050] The carbonyl sulfide removal method in this embodiment includes the following steps:

[0051] The crude feedstock gas containing carbonyl sulfide is coal-derived syngas, and its components, by volume fraction, are as follows: 45.0%, CO3 5.0%, 18.5%, COS 1.0%, and the remainder being small amounts of inert gases.

[0052] 1. Preparation of compound accelerators:

[0053] The main accelerator is tetrabutylammonium bromide, and the co-accelerator is sodium dodecyl sulfate. The mass ratio of the main accelerator to the co-accelerator is 200:1, and an aqueous solution of the compound accelerator with a mass concentration of 25% is prepared.

[0054] 2. Pretreatment:

[0055] The crude feed gas is cooled to 10°C and the pressure is controlled at 2.0 MPa to obtain a feed gas containing carbonyl sulfur.

[0056] 3. Hydration:

[0057] The raw gas containing carbonyl sulfide flows through the first pressure and flow regulating valve and the first cooler to the hydrate generator for hydration. The raw gas and the aqueous solution containing the compound accelerator are mixed at a gas-liquid volume ratio of 100:1. The hydration temperature is controlled at 10℃, the hydration pressure at 1.8MPa, the stirring speed at 200r / min, and the residence time of the raw gas in the aqueous solution is controlled at 10min. This allows carbonyl sulfide and water molecules to combine to form carbonyl sulfide hydrate. After the process, a gas-liquid-solid coexistence system is obtained. The gas-liquid-solid coexistence system includes a slurry containing carbonyl sulfide hydrate and a purified gas that has been balanced with the slurry and has had carbonyl sulfide removed.

[0058] 4. Separation and Regeneration:

[0059] The gas-liquid-solid coexistence system was separated by sedimentation to obtain purified gas with carbonyl sulfide removed and a slurry containing carbonyl sulfide hydrate. The COS content in the purified gas was reduced to 1 ppm, and the carbonyl sulfide removal rate reached 99.9%. The total recovery rate of CO was 98.0%. The slurry containing carbonyl sulfur hydrate was decomposed at 40℃ and 0.2MPa to obtain the dissociated compound accelerator and release the enriched carbonyl sulfur gas. The dissociated compound accelerator was cooled by a pump and a second cooler and then returned to the hydration reactor for recycling.

[0060] Example 2

[0061] The carbonyl sulfide removal method in this embodiment includes the following steps:

[0062] The crude feedstock gas containing carbonyl sulfide is coal-derived syngas, and its components, by volume fraction, are as follows: 40.0%, CO3 0.0%, 29.0%, COS 0.3%, and the remainder being small amounts of inert gases.

[0063] 1. Preparation of compound accelerators:

[0064] The main accelerator is tetrahydrofuran, and the co-accelerator is sodium dodecylbenzenesulfonate. The mass ratio of the main accelerator to the co-accelerator is 300:1, and an aqueous solution of the compound accelerator with a mass concentration of 19% is prepared.

[0065] 2. Pretreatment:

[0066] The crude feed gas is cooled to 10°C and the pressure is controlled at 1.6 MPa to obtain a feed gas containing carbonyl sulfur.

[0067] 3. Hydration:

[0068] The carbonyl sulfide-containing feed gas flows through the first pressure and flow regulating valve and the first cooler to the hydrate generator for hydration. The feed gas and the aqueous solution containing the compound accelerator are mixed at a gas-liquid volume ratio of 200:1. The hydration temperature is controlled at 8°C, the hydration pressure at 1.5 MPa, the stirring speed at 150 r / min, and the residence time of the feed gas in the aqueous solution is controlled at 15 min. This allows carbonyl sulfide and water molecules to combine to form carbonyl sulfide hydrate. After the process, a gas-liquid-solid coexistence system is obtained. The gas-liquid-solid coexistence system includes a slurry containing carbonyl sulfide hydrate and purified gas that has been balanced with the slurry and has had carbonyl sulfide removed.

[0069] 4. Separation and Regeneration:

[0070] The gas-liquid-solid coexistence system was separated by sedimentation to obtain purified gas with carbonyl sulfide removed and a slurry containing carbonyl sulfide hydrate. The COS content in the purified gas was reduced to 1 ppm, and the carbonyl sulfide removal rate reached 99.93%. The total recovery rate of CO was 98.20%. The slurry containing carbonyl sulfur hydrate was decomposed at 40℃ and 0.2MPa to obtain the dissociated compound accelerator and release the enriched carbonyl sulfur gas. The dissociated compound accelerator was cooled by a pump and a second cooler and then returned to the hydration reactor for recycling.

[0071] Example 3

[0072] This embodiment is basically the same as Embodiment 1, except that in the hydration reaction process, the raw material gas and the aqueous solution containing the compound accelerator are mixed at a gas-liquid volume ratio of 5:1. The remaining methods and steps are basically the same as in Embodiment 1.

[0073] Example 4

[0074] This embodiment is basically the same as Embodiment 1, except that in the hydration reaction process, the raw material gas and the aqueous solution containing the compound accelerator are mixed at a gas-liquid volume ratio of 500:1. The remaining methods and steps are basically the same as in Embodiment 1.

[0075] Example 5

[0076] This embodiment is basically the same as Embodiment 1, except that the mass ratio of the main accelerator to the co-accelerator is 100:1. The remaining methods and steps are basically the same as in Embodiment 1.

[0077] Example 6

[0078] This embodiment is basically the same as Embodiment 1, except that the mass ratio of the main accelerator to the co-accelerator is 350:1, and in step 3), the residence time of the raw material gas in the aqueous solution is controlled to be 15 minutes. The remaining methods and steps are basically the same as in Embodiment 1.

[0079] Example 7

[0080] The carbonyl sulfide removal method in this embodiment includes the following steps:

[0081] The crude feedstock gas containing carbonyl sulfide is coal-derived syngas, and its components, by volume fraction, are as follows: 45.0%, CO3 5.0%, 18.5%, COS 1.0%, and the remainder being small amounts of inert gases.

[0082] 1. Preparation of compound accelerators:

[0083] The main accelerator is tetrahydrofuran, and the co-accelerator is sodium dodecyl sulfate. The mass ratio of the main accelerator to the co-accelerator is 300:1, and an aqueous solution of the compound accelerator with a mass concentration of 19% is prepared.

[0084] 2. Pretreatment:

[0085] The crude feed gas is cooled to 10°C and the pressure is controlled at 2.0 MPa to obtain a feed gas containing carbonyl sulfur.

[0086] 3. Hydration:

[0087] The carbonyl sulfide-containing feed gas flows through the first pressure and flow regulating valve and the first cooler to the hydrate generator for hydration. The feed gas and the aqueous solution containing the compound accelerator are mixed at a gas-liquid volume ratio of 5:1. The hydration temperature is controlled at 10℃, the hydration pressure at 1.8MPa, the stirring speed at 200r / min, and the residence time of the feed gas in the aqueous solution is controlled at 15min. This allows carbonyl sulfide and water molecules to combine to form carbonyl sulfide hydrate. After the reaction, a gas-liquid-solid coexistence system is obtained. The gas-liquid-solid coexistence system includes a slurry containing carbonyl sulfide hydrate and a purified gas that has been phase-equilibrated with the slurry and has had carbonyl sulfide removed.

[0088] Example 8

[0089] The carbonyl sulfide removal method in this embodiment includes the following steps:

[0090] The crude feedstock gas containing carbonyl sulfide is coal-derived syngas, and its components, by volume fraction, are as follows: 45.0%, CO3 5.0%, 18.5%, COS 1.0%, and the remainder being small amounts of inert gases.

[0091] 1. Preparation of compound accelerators:

[0092] The main accelerator is tetrabutylammonium bromide, and the co-accelerator is sodium dodecyl sulfate. The mass ratio of the main accelerator to the co-accelerator is 300:1, and an aqueous solution of the compound accelerator with a mass concentration of 19% is prepared.

[0093] 2. Pretreatment:

[0094] The crude feed gas is cooled to 10°C and the pressure is controlled at 2.0 MPa to obtain a feed gas containing carbonyl sulfur.

[0095] 3. Hydration:

[0096] The carbonyl sulfide-containing feed gas flows through a first pressure and flow regulating valve and a first cooler to a hydrate generator for hydration. The feed gas and an aqueous solution containing a compound accelerator are mixed at a gas-liquid volume ratio of 500:1. The hydration temperature is controlled at 10°C, the hydration pressure at 1.8 MPa, the stirring speed at 200 r / min, and the residence time of the feed gas in the aqueous solution is controlled at 10 min, allowing carbonyl sulfide and water molecules to combine to form carbonyl sulfide hydrate. After the reaction, a gas-liquid-solid coexistence system is obtained, which includes a slurry containing carbonyl sulfide hydrate and purified gas after phase equilibrium with the slurry and removal of carbonyl sulfide. The remaining methods and steps are basically the same as in Example 1.

[0097] Comparative Example 1

[0098] This comparative example is basically the same as Example 1, except that the main accelerator tetrabutylammonium bromide was not added, and only sodium dodecyl sulfate was added. For details of the differences, please refer to Table 1.

[0099] Comparative Example 2

[0100] This comparative example is basically the same as Example 1, except that sodium dodecyl sulfate, a co-accelerator, was not added, and only tetrabutylammonium bromide was added. For details of the differences, please refer to Table 1.

[0101] Table 1. Working solution for removing carbonyl sulfur hydrates using the hydrate method.

[0102] For the purified gas COS content, carbonyl sulfide removal rate, and total CO recovery rate in each of the above embodiments and comparative examples, the test results are shown in Table 2.

[0103] 1) The carbonyl sulfide removal rate is calculated by detecting the initial content of carbonyl sulfide in the raw gas and the residual content of carbonyl sulfide in the purified gas. The specific calculation formula is as follows:

[0104] η = ((C in - C out ) / C in ) × 100%, where: η - carbonyl sulfide removal rate (%); C in - initial volume concentration (or mass concentration) of carbonyl sulfide in the raw gas, unit ppm (or mg / m³), measured by the detection device at the raw gas inlet; C out - residual volume concentration (or mass concentration) of carbonyl sulfide in the purified gas, unit ppm (or mg / m³), measured in real time by the on-line monitoring probe for carbonyl sulfide equipped at the purified gas outlet.

[0105] 2) Total CO recovery rate: The volume fractions and gas flow rates of hydrogen and carbon monoxide in the inlet raw gas and outlet purified gas are detected respectively, and the total CO recovery rate is calculated by material balance. The specific steps are as follows: Set on-line chromatographic sampling ports at the raw gas inlet and purified gas outlet of the device; Use a gas chromatograph to measure the volume concentration C H2,进 , CO volume concentration C CO,进 in the raw gas respectively; Synchronously measure the volume concentration C H2,出 , CO volume concentration C CO,出 in the purified gas; Use a flow meter to measure the raw gas inlet volume flow rate Q 进 , purified gas outlet volume flow rate Q 出 respectively; All concentrations are in volume fraction, and the flow rates are uniformly converted to volume flow rates under the same temperature and pressure standard state. Total CO recovery rate η 总 The calculation formula is as follows: η 总 = (Q 进 × (C H2,进 + C CO,进 ) - Q 出 × (C H2,出 + C CO,出 )) / (Q 进 × (C H2,进 + C CO,进 )) × 100%. η 总 : Compared with the total recovery rate of CO, %; Q 进 : Standard volumetric flow rate of raw gas; Q 出 Standard volumetric flow rate of purified gas; C H2,进 C CO,进 : in raw gas CO volume fraction, C H2,出 C CO,出 Purified gas CO volume fraction.

[0106] Table 2 Separation conditions and effects of carbonyl sulfide removal by hydrate method

[0107]

[0108] Analysis of Table 2 shows that, compared with Comparative Examples 1-2, Examples 1-8 introduced a compound accelerator in the carbonyl sulfide removal process, which can achieve efficient and selective removal of carbonyl sulfide under near-room temperature (1-21℃) and medium-low pressure (0.1-6.0MPa) conditions.

[0109] It should be noted that: for experimental steps or conditions not specified in the examples, the procedures and conditions described in conventional experimental procedures in the literature of this art can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for removing carbonyl sulfide, characterized in that, Includes the following steps: S1. The raw material gas containing carbonyl sulfide is passed into an aqueous solution containing a compound accelerator, and a hydration reaction is carried out at 1~21℃ and 0.1MPa~6.0MPa. The carbonyl sulfide and water are converted into carbonyl sulfide hydrate, forming a gas-liquid-solid coexistence system. The gas-liquid-solid coexistence system includes a slurry containing carbonyl sulfide hydrate and purified gas after carbonyl sulfide removal. S2. Perform gas-liquid separation on the gas-liquid-solid coexistence system to obtain purified gas with carbonyl sulfide removed and slurry containing carbonyl sulfide hydrate; The compound accelerator includes a primary accelerator and a secondary accelerator. The primary accelerator includes quaternary ammonium salt compounds and / or cyclic ether compounds, and the secondary accelerator includes sulfonate surfactants and / or glycoside surfactants.

2. The carbonyl sulfide removal method according to claim 1, characterized in that, The gas-liquid volume ratio of the carbonyl sulfur-containing feed gas and the aqueous solution containing the compound accelerator at standard conditions of 273.15 K, 101.325 kPa is (5~500):1; And / or, the mass percentage of the compound accelerator in the aqueous solution containing the compound accelerator is 6%-30%.

3. The carbonyl sulfide removal method according to claim 1 or 2, characterized in that, The mass ratio of the main accelerator to the auxiliary accelerator is (200~3000):

1.

4. The carbonyl sulfide removal method according to any one of claims 1-3, characterized in that, The quaternary ammonium salt compounds include tetrabutylammonium bromide and / or tetrabutylammonium chloride; And / or, the cyclic ether compounds include tetrahydrofuran and / or tetrahydropyran; And / or, the sulfonate surfactants include sodium dodecyl sulfate and / or sodium dodecylbenzene sulfonate; And / or, the glycoside surfactants include glucosinolate surfactants and / or glucosinolate surfactants; And / or, in step S1, the residence time of the carbonyl sulfur-containing feed gas in the aqueous solution containing the compound accelerator is 10s~15min.

5. The carbonyl sulfide removal method according to any one of claims 1-4, characterized in that, The preparation process of the carbonyl sulfur-containing feed gas in step S1 includes: cooling the carbonyl sulfur-containing crude feed gas to 1-21°C to obtain the carbonyl sulfur-containing feed gas.

6. The method for removing carbonyl sulfide according to any one of claims 1-5, characterized in that, Step S2 is followed by: decomposing the liquid material containing carbonyl sulfur hydrate to obtain carbonyl sulfur-rich gas and the dissociated compound accelerator, returning the aqueous solution of the dissociated compound accelerator to the aqueous solution containing the compound accelerator in step S1 for recycling, and enriching and recovering the carbonyl sulfur gas.

7. The carbonyl sulfide removal method according to claim 6, characterized in that, During the decomposition process, the temperature is 25-45℃ and the pressure is 0.1-6.0MPa.

8. A carbonyl sulfide removal apparatus for performing the carbonyl sulfide removal method according to any one of claims 1-7, characterized in that, It includes a hydration unit and a separation unit connected in sequence.

9. The carbonyl sulfide removal apparatus according to claim 8, characterized in that, The hydration unit includes a high-pressure reactor or a tubular reactor; preferably, the high-pressure reactor is equipped with a stirring device and a spraying device. And / or, the separation unit includes a sedimentation separator or a centrifugal separator.

10. The carbonyl sulfide removal apparatus according to claim 8 or 9, characterized in that, The hydration unit is equipped with an inlet for raw material gas and an aqueous solution containing a compound accelerator, and an outlet for a gas-liquid mixture. The separation unit is provided with a gas-liquid mixture inlet, a purified gas outlet, and a slurry outlet containing carbonyl sulfur hydrate, which are connected to the gas-liquid mixture outlet of the hydration unit. The carbonyl sulfide removal device also includes a pretreatment unit, a decomposition unit, and a circulation unit; The pretreatment unit is provided with a crude raw material gas inlet and a raw material gas outlet; the raw material gas outlet of the pretreatment unit is connected to the raw material gas inlet of the hydration unit. The decomposition unit is provided with a carbonyl sulfur hydrate-containing liquid phase material inlet, a carbonyl sulfur-rich gas outlet, and a dissociated liquid phase material outlet connected to the liquid phase material outlet of the separation unit. The circulation unit includes a dissociated liquid phase material inlet and a circulating liquid phase material outlet; the dissociated liquid phase material inlet of the circulation unit is connected to the dissociated liquid phase material outlet of the decomposition unit; the circulating liquid phase material outlet of the circulation unit is connected to the hydration unit.

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