CN109420417B - Process and device for separating acid gas by hydration method - Google Patents

Process and device for separating acid gas by hydration method Download PDF

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CN109420417B
CN109420417B CN201710715572.1A CN201710715572A CN109420417B CN 109420417 B CN109420417 B CN 109420417B CN 201710715572 A CN201710715572 A CN 201710715572A CN 109420417 B CN109420417 B CN 109420417B
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hydrate
gas
reactor
working solution
hydration
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CN109420417A (en
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孟凡飞
王海波
彭德强
陈新
王璐瑶
廖昌建
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Sinopec Dalian Petrochemical Research Institute Co ltd
China Petroleum and Chemical Corp
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China Petroleum and Chemical Corp
Sinopec Dalian Research Institute of Petroleum and Petrochemicals
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/75—Multi-step processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/52—Hydrogen sulfide
    • B01D53/526—Mixtures of hydrogen sulfide and carbon dioxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/77—Liquid phase processes
    • B01D53/78—Liquid phase processes with gas-liquid contact
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/96—Regeneration, reactivation or recycling of reactants
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/22—Alkali metal sulfides or polysulfides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/22—Alkali metal sulfides or polysulfides
    • C01B17/32—Hydrosulfides of sodium or potassium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/30—Alkali metal compounds
    • B01D2251/304—Alkali metal compounds of sodium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/60—Inorganic bases or salts
    • B01D2251/604—Hydroxides

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Abstract

The invention discloses a process and a device for separating acid gas by a hydration method, wherein the device comprises a hydration reactor, a hydrate decomposer, an absorption reactor and a product tank; the acid gas feeding pipeline is connected with a gas phase inlet of the hydration reactor, a liquid phase outlet of the hydration reactor is connected with a hydrate slurry inlet of the hydrate decomposer, and a cold clear liquid outlet and a regenerated hydrate working liquid outlet of the hydrate decomposer are connected with a liquid phase inlet of the hydrate reactor after passing through a cooler; the gas phase outlet of the hydrate decomposer is connected with the gas phase inlet of the absorption reactor, the gas phase outlet of the absorption reactor is connected with the purified gas outlet pipeline, and the liquid phase inlet of the absorption reactor is connected with the alkali liquor inlet pipeline. The invention fully utilizes the energy in the whole process, reasonably matches the endothermic reaction of the hydrate decomposition and the exothermic reaction of the alkaline absorption, and greatly reduces the energy consumption.

Description

Process and device for separating acid gas by hydration method
Technical Field
The invention relates to a method and a device for treating acid gas, in particular to a technology for purifying acid gas containing carbon dioxide and hydrogen sulfide and recycling pollutants.
Background
The acid gas of the refinery is in stoneA tail gas generated during oil processing contains H as main component2S and CO2. The acid gas of the refinery mainly comes from devices such as acid water stripping, recycle hydrogen desulfurization, dry gas and liquefied gas desulfurization and the like. The acid gas amount of large-scale refinery is larger (annual sulfur production is more than 5000 t/a), and an acid gas treatment device for producing sulfur is generally established for H2And S is recycled. For medium and small refineries (annual sulfur production is less than 5000 t/a), the cost for building a sulfur device is higher due to small amount of acid gas, most small refineries basically treat the acid gas in a combustion emission mode, and the method not only causes resource waste, but also generates SO (sulfur oxide) by combustion2Brings great pressure to environmental protection.
At present, the treatment of acid gas in refinery can be divided into products such as preparation of sulfur, preparation of sulfuric acid, preparation of sulfite, NaHS and the like according to different products prepared by recovery.
The preparation of the sulfur product mainly comprises two mature technologies, one is a two-stage Claus + tail gas hydrogenation reduction + solvent absorption process technology; the other is the LO-CAT process technology developed by Merichem gas technology products, Inc. of America. The two-stage Claus + tail gas hydrogenation reduction + solvent absorption technology is mature, the quality of sulfur products is stable, but the Claus technology only can treat acid gas with high concentration and has no advantage for the treatment of acid gas in small refineries due to long flow, large investment, high energy consumption and high requirement on safety control of devices. LO-CAT Process Using Multichelated iron catalyst for H2S is directly converted into elemental sulfur, and the method can be suitable for the working condition with large fluctuation of acid gas quantity, H2The removal rate of S is high, but the LO-CAT has the problems of high operation cost, slightly inferior sulfur purity and color compared with the Claus process, blockage of sulfur particles generated in the production process, high catalyst and patent use cost and the like, so that the technology is difficult to popularize in the acid gas treatment of small refineries.
The acid gas acid making technology can directly utilize acid gas to make acid, and has the advantages of low investment, low cost, strong adaptability and easy operation of production process. However, the production process of sulfuric acid is complex, the occupied area is large, and the transportation and storage of sulfuric acid have certain difficulty, which becomes a limiting factor. The technological process for producing sulfite by acid gas is simple, product diversification can be realized by adopting different absorbents, but the problems of serious equipment corrosion, higher maintenance cost, unsmooth product sale and the like exist in the production process, and the method has certain limitation.
The comprehensive utilization of acid gas can adopt the novel absorption desulfurization process with less investment to produce chemical product sodium sulfide (Na)2S/NaHS). The sodium sulfide can be widely applied to industries such as mineral separation, pesticides, dyes, leather production, organic synthesis and the like. The refinery acid gas contains H in addition to2The S gas also contains a certain amount of CO2Gas, in the process for producing alkali sulphide, CO2The gas can be mixed with raw material alkali liquor to produce Na2CO3/NaHCO3Impurities cause the blockage of process pipelines in the production process, so that the production device cannot continuously run for a long period, and the problems of high alkali consumption, poor product purity and the like exist. CN103551018A discloses a method for purifying and recycling sulfur-containing tail gas, which utilizes barium sulfide to treat CO in gas2Removing to obtain H2The S gas can produce high-quality NaHS products, but barium sulfite and barium carbonate precipitates are generated, so that the processing is difficult. CN1109020A discloses a method for preparing NaHS by one-step method, which adopts solid-containing slurry of lime and sodium sulfate to react with CO2H of (A) to (B)2S gas is treated, and calcium carbonate and the like are precipitated. The methods for preparing NaHS described in patents CN101186280A and CN101337661A also face the problem of waste residue treatment. Patent CN103754833A discloses a device and a method for producing NaHS by using refinery dry gas, which utilizes a supergravity technology to selectively desulfurize the dry gas to obtain 99% H2The purity of NaHS produced by S gas can reach more than 42 percent, but the technology has long raw material gas pretreatment process, complex production device and higher regeneration energy consumption of rich absorption liquid. The NaHS production technologies described in CN103446849A, CN103466559A and CN103638802A also face the problems of complex flow, high amine liquid regeneration energy consumption in acid gas pretreatment and the like.
In summary, the treatment of acid gas in small refineries needs to comprehensively consider factors such as safety, environmental protection, economy and the like, so that a comprehensive treatment mode with short flow, less investment, simple operation, low energy consumption and operation cost and certain economic benefit is required.
The hydrate separation technology is a hot point of domestic and foreign research in recent years, and the technology is paid much attention by virtue of the advantages of simple flow, mild conditions, flexible operation, greenness, no pollution and the like. The principle of separating the mixed gas by the hydrate technology is that the pressure difference of hydrates formed by different gases is large, and the separation of the components of the mixed gas can be realized by utilizing the pressure difference of the hydrates formed by the different gases and controlling the generation conditions. H in acid gases2S gas and CO2The difference of phase equilibrium conditions when the gas and water form hydrate is large, so the acid gas can be separated by the technology. However, the energy consumption of the hydrate in the process of generating and decomposing is a main factor for restricting the application of the technology. In addition, the liquid phase for separating gas by the traditional hydrate method adopts aqueous solution, the generated hydrate is generally in a crystalline form, the mobility of the formed hydrate is poor, and the formed hydrate is easy to aggregate and block, so that the continuity and large-scale application of the related technology of the hydrate are directly restricted. Although the related technology adopts granulation and hydrate slurry form for conveying in order to solve the mobility problem of the hydrate, the granulation technology needs a dehydration procedure, and the dehydrated hydrate is processed by a granulator, so that the process is complex; the hydrate slurry is in a form of circularly conveying the hydrate and the solution which does not react to generate the hydrate to solve the mobility problem, but the mixed slurry needs to be integrally heated when the hydrate is decomposed, and is integrally cooled after the gas is decomposed and released, so that the energy consumption is greatly increased, and the operation cost is increased.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a process and a device for separating acid gas by a hydration method, which can treat the acid gas and simultaneously produce Na2S or NaHS chemical products organically combine environmental management and chemical production into an integrated process. Compared with the prior art, the method can economically and efficiently treat CO under the mild condition2Gas and H2The acid gas of the S gas is pretreated to ensure the hydration methodGood fluidity of hydrate in the separation unit, control of Na in the alkaline absorption unit2CO3 / NaHCO3Content, ensuring continuous and long-period stable operation of the device; the energy in the whole process is fully utilized, the heat absorption of the hydrate decomposition and the reaction heat release of the alkali absorption are reasonably matched, and the energy consumption is greatly reduced; the whole treatment process is environment-friendly and reliable, and no three wastes are generated.
The invention provides a device for separating acid gas by a hydration method, which comprises a hydration reactor, a hydrate decomposer, an absorption reactor and a product tank, wherein the hydration reactor is connected with the absorption reactor; the acid gas feeding pipeline is connected with a gas phase inlet of the hydration reactor, a liquid phase outlet of the hydration reactor is connected with a hydrate slurry inlet of a slurry separation unit of the hydrate decomposer, and a cold clear liquid outlet and a regenerated hydrate working liquid outlet of the hydrate decomposer are connected with a liquid phase inlet of the hydrate reactor after passing through a cooler; a gas phase outlet at the top of the hydrate decomposer is connected with a gas phase inlet of the absorption reactor, a gas phase outlet of the absorption reactor is connected with a purified gas outlet pipeline, a liquid phase outlet of the absorption reactor is divided into two paths, the first path is connected with the product tank, the second path is connected with a circulating liquid inlet of the absorption reactor through heat exchange equipment in the hydrate decomposer, and a liquid phase inlet of the absorption reactor is connected with an alkali liquor inlet pipeline; the hydrate decomposer comprises a slurry separation unit and a decomposition unit, and the slurry separation unit is communicated with the decomposition unit through a connecting channel; the slurry separation unit is divided into an upper part and a lower part by a filter screen partition plate assembly, the upper part is sequentially provided with a hydrate slurry inlet, a cleaning liquid inlet and a connecting channel interface from top to bottom, the lower part is a cold clear liquid storage tank, and the bottom of the storage tank is provided with a cold clear liquid outlet; the decomposition unit is sequentially provided with a hydrate decomposition gas outlet, a connecting channel interface and a regeneration liquid storage tank from top to bottom, and the regeneration liquid storage tank is internally provided with a heat exchange unit, a stripping gas inlet and a regenerated hydrate working liquid outlet.
In the above acid gas plant, the acid gas feed line is provided with a compressor for ensuring that the acid gas pressure matches the hydration reactor operating pressure.
In the above acid gas apparatus, the hydration reactor is a device which is beneficial to gas-liquid mass transfer and has good heat transfer effect, and the form is not limited, and may be one of stirring type, spray type, bubbling type, sieve plate type, packing type, supergravity or impinging stream type, and the like, and preferably a reaction device which takes a liquid phase as a continuous phase. The hydration reactor can be arranged into one stage or a plurality of stages according to the mixed gas separation requirement.
In the above acid gas apparatus, the absorption reactor is a gas-liquid mass transfer reaction device, specifically, one of a bubble column reactor, a packed column reactor, an impinging stream reactor, a rotating bed reactor and a venturi reactor, and is preferably a rotating bed reactor. The absorption reactor can be arranged into one stage or a plurality of stages according to the requirements of reaction products.
In the acid gas device, the connecting channel in the hydrate decomposer is horizontally arranged or obliquely arranged at a certain angle, when the connecting channel is obliquely arranged, the connecting channel interface of the slurry separation unit is higher than the connecting channel interface of the decomposition unit, and the oblique angle forms 10-60 degrees, preferably 15-45 degrees with the horizontal plane. The lower plane of the connecting channel is arranged at 1/2-3/4 of the vertical height of the slurry separation unit.
In the acid gas device, the filter screen partition plate assembly in the hydrate decomposer can be horizontally arranged or obliquely arranged at a certain angle, and the upper plane of the filter screen partition plate assembly and the lower plane of the connecting channel are arranged on the same plane. The filter screen clapboard component adopts any one of a filler structure, a wire mesh structure or a screen mesh structure to filter the hydrate slurry, the filtered hydrate-rich phase slurry (or particle crystallized) is conveyed to the decomposition unit, and the filtrate (cold clear liquid) enters a liquid storage tank below. The parameters of the filter screen separator assembly, such as pore size, porosity, filling thickness, etc., need to be determined according to the gas mixture system, the type of additive and what structural hydrate is formed.
In the acid gas device, the hydrate slurry inlet in the hydrate decomposer is connected with a spraying assembly, and the spraying assembly can adopt a liquid distributor known in the field, so that the hydrate slurry can be sprayed and uniformly distributed, and the coverage area is ensured to be the section of the whole slurry separation unit.
In the acid gas device, a cleaning liquid inlet in the hydrate decomposer is connected with a nozzle, the nozzle can adopt any known form in the field, the cleaning liquid can be sprayed to the filter screen partition plate assembly at a high speed, the coverage area accounts for more than 70% of the area of the whole filter screen partition plate assembly, the washing and scouring effect on the filter screen partition plate assembly is realized, the nozzle is arranged at a certain inclination angle, the inclination direction faces to the connecting channel, and the inclination angle and the vertical center line form 5-45 degrees, preferably 10-30 degrees.
In the acid gas device, the liquid holdup of a cold clear liquid storage tank in the hydrate decomposer is 1/3-2/3 of the volume of the liquid storage tank.
In the acid gas device, the liquid holding capacity of a regeneration liquid storage tank in the hydrate decomposer is 1/2-5/6 of the volume of the storage tank.
In the acid gas device, a dividing wall type heat exchange device is arranged in a heat exchange unit in the hydrate decomposer, the hot fluid is heated in a coil pipe mode through a hot fluid pipe running process, and fins can be additionally arranged outside the coil pipe to strengthen heat exchange.
In the acid gas device, a plurality of groups of baffle plates are arranged among the coil pipes of the heat exchange equipment in the decomposition unit in the hydrate decomposer, so that the functions of supporting the coil pipes and strengthening the heat exchange effect are achieved.
In the acid gas device, the hydrate decomposer takes the product liquid produced by the absorption reactor as the heat source of the heat exchange equipment to lead the H to be enriched2And (4) heating the hydrate working solution of the S gas, and returning the hydrate working solution to the absorption reactor.
In the acid gas device, a stripping gas inlet in the hydrate decomposer is connected with a gas distributor, the gas distributor and the cross section of the decomposition unit are uniformly distributed to the maximum extent, so that stripping gas is in countercurrent flowing contact with the hydrate-rich slurry in the decomposition unit, the gas distributor can adopt a gas distributor known in the field, and the stripping gas can be regenerated gas decomposed by the unit and can also be any gas which does not react with the subsequent processing process.
In the acid gas device, a regenerated hydrate working solution outlet at the bottom of a decomposition unit in a hydrate decomposer is divided into two paths, wherein one path is connected with a cleaning solution inlet through a pipeline, a part of regenerated hydrate working solution discharged from the bottom of the decomposition unit is used as an internal circulation cleaning solution, and the volumetric flow of the regenerated hydrate working solution used as the internal circulation cleaning solution accounts for 1/5-1, preferably 1/3-1/2, of the volumetric flow of the total regenerated hydrate working solution.
The invention provides a process for separating acid gas by a hydration method, which comprises the following steps:
(1) the raw material acid gas enters a hydration reactor to react with hydrate working solution, and H in the acid gas2S gas reacts with the hydrate working solution and enters the hydrate phase to form hydrate slurry, CO2Enriching in the gas phase and discharging out of the hydration reactor;
(2) h-enriched fraction obtained in step (1)2The hydrate slurry of the S gas enters a hydrate decomposer, cold clear liquid and hydrate-rich phase slurry are obtained after the treatment of a slurry separation unit of the hydrate decomposer, and the cold clear liquid enters a cold clear liquid storage tank below;
(3) the hydrate-rich phase slurry obtained in the step (2) enters a decomposition unit under the action of a cleaning solution, exchanges heat with product liquid from an absorption reactor in a regenerated liquid storage tank, is in countercurrent contact with stripping gas introduced from the bottom of the decomposition unit, and is decomposed to release H2S, decomposing the gas and the hydrate to obtain regenerated working solution, mixing the regenerated hydrate working solution with the cold clear solution, cooling, and returning to the hydration reactor for recycling;
(4) h obtained in step (3)2And the S gas enters an absorption reactor to react with alkali liquor, the treated tail gas is discharged, the obtained product liquid is divided into two paths, the first path enters a hydrate decomposer to be used as a heat source for heat exchange and then returns to the absorption reactor, and the second path enters a product tank.
In the process, the pressure of the acid gas in the step (1) is matched with the operation pressure of a hydration reactor, the pressure of the acid gas is 0.1-3.0 Mpa, preferably 0.3-1.5 Mpa, and the pressure can be increased by a compressor when the pressure of the acid gas is insufficient.
In the process, the ratio of the amount of the hydrate working solution in the step (1) to the volume of the acid gas is (Standard condition) of 5 to 100L/m3Preferably 10 to 50L/m3。
In the process, the hydration reactor in the step (1) is a device which is beneficial to gas-liquid mass transfer and has a good heat transfer effect, the form is not limited, the hydration reactor can be one of stirring type, spraying type, bubbling type, sieve plate type, packing type, hypergravity or impinging stream type and the like, and a reaction device taking a liquid phase as a continuous phase is preferred. The hydration reactor can be arranged into one stage or a plurality of stages according to the mixed gas separation requirement.
In the process of the invention, H is utilized in the hydration reactor2S and CO2The gas forms the phase equilibrium difference of hydrate, and realizes the separation of mixed gas by controlling the generation condition. The operating conditions of the hydration reactor were: the pressure is 0.1-3.0 Mpa, preferably 0.3-1.5 Mpa, the temperature is 0-15 ℃, preferably 3-10 ℃.
In the process of the invention, in the hydration reactor in the step (1), hydrate slurry refers to a mixed solution of a formed hydrate and an unreacted hydrate working solution, and the volume ratio of the hydrate in the hydrate slurry is controlled to be 30-80%, preferably 50-70% by reaction.
In the process, H in tail gas of the hydration reactor in the step (1)2The volume fraction of S is controlled to be 1-20%, and CO is controlled2The volume fraction is higher than 80%, and the sulfur removal agent can be integrated into a refinery gas desulfurization system upstream of a refinery acid gas for centralized treatment.
In the process, the operating conditions of the hydrate decomposer in the step (2) are as follows: the pressure is 0.02 Mpa-2.0 Mpa, preferably 0.05 Mpa-1.0 Mpa, the temperature of a slurry separation unit is 0-10 ℃, and the temperature of a decomposition unit is 10-40 ℃.
In the process, the slurry separation unit in the step (2) separates the hydrate slurry into cold clear liquid and hydrate-rich phase slurry, wherein the volume content of the hydrate in the cold clear liquid is lower than 10%, and the volume content of the hydrate in the hydrate-rich phase slurry is higher than 80%.
In the process of the invention, the stripping gas in the step (3) can be any gas which does not react with the subsequent processing process, such as nitrogen and inert gas, and can also be part of the cycle of the decomposed gas obtained by the decomposition unit.
In the method, the temperature of the regenerated hydrate working solution and the cold clear solution in the step (3) is controlled to be 0-15 ℃, preferably 3-10 ℃ after being cooled, and the regenerated hydrate working solution and the cold clear solution are returned to the hydration reactor for recycling.
In the process, H in the gas released by the hydrate decomposer in the step (3)2S volume fraction higher than 95%, CO2The volume fraction is less than 5%.
In the process of the invention, the absorption reactor is a gas-liquid mass transfer reaction device, preferably a reaction device taking a gas phase as a continuous phase, specifically one of a bubble column reactor, a packed column reactor, an impinging stream reactor, a rotating bed reactor and a venturi reactor, preferably a rotating bed reactor. The absorption reactor can be arranged into one stage or a plurality of stages according to the requirements of reaction products.
In the process of the invention, the operating conditions of the absorption reactor are as follows: the pressure is 0.02 Mpa-2.0 Mpa, preferably 0.1 Mpa-1.0 Mpa, the temperature is 70-95 ℃, and preferably 80-90 ℃.
In the process, the alkali liquor is NaOH solution, the mass concentration is 20-60%, preferably 32-48%, and the dosage of the alkali liquor is determined according to the H released in the step (4)2And (4) adjusting the content of S.
In the process, the product liquid obtained by the reaction of the absorption reactor in the step (4) is divided into two paths, the first path enters a hydrate decomposer to be used as a heat source, the second path enters a product tank, and the flow rate ratio of the product liquid of the first path to the product liquid of the second path is 20/1-1/1, preferably 10/1-2/1.
In the process, the hydrate decomposer adopts the hydrate decomposer with the following structure, the hydrate decomposer comprises a slurry separation unit and a decomposition unit, and the slurry separation unit is communicated with the decomposition unit through a connecting channel; the slurry separation unit is divided into an upper part and a lower part by a filter screen partition plate assembly, the upper part is sequentially provided with a hydrate slurry inlet, a cleaning liquid inlet and a connecting channel interface from top to bottom, the lower part is a cold clear liquid storage tank, and the bottom of the storage tank is provided with a cold clear liquid outlet; the decomposition unit is sequentially provided with a hydrate decomposition gas outlet, a connecting channel interface and a regeneration liquid storage tank from top to bottom, and the regeneration liquid storage tank is internally provided with a heat exchange unit, a stripping gas inlet and a regenerated hydrate working liquid outlet.
In the hydrate decomposer, the connecting channel is horizontally arranged or obliquely arranged at a certain angle, when the connecting channel is obliquely arranged, the connecting channel interface of the slurry separation unit is higher than the connecting channel interface of the decomposition unit, and the oblique angle forms 10-60 degrees, preferably 15-45 degrees with the horizontal plane. The lower plane of the connecting channel is arranged at 1/2-3/4 of the vertical height of the slurry separation unit.
In the hydrate decomposer, the filter screen partition plate assembly can be horizontally arranged or obliquely arranged at a certain angle, and the upper plane of the filter screen partition plate assembly and the lower plane of the connecting channel are arranged on the same plane. The filter screen clapboard component adopts any one of a filler structure, a wire mesh structure or a screen mesh structure to filter the hydrate slurry, the filtered hydrate-rich phase slurry (or particle crystallized) is conveyed to the decomposition unit, and the filtrate (cold clear liquid) enters a liquid storage tank below. The parameters of the filter screen separator assembly, such as pore size, porosity, filling thickness, etc., need to be determined according to the gas mixture system, the type of additive and what structural hydrate is formed.
In the hydrate decomposer, the hydrate slurry inlet is connected with a spraying assembly, the spraying assembly can adopt a liquid distributor known in the art, the hydrate slurry can be sprayed and uniformly distributed, and the coverage area is ensured to be the section of the whole slurry separation unit.
In the hydrate decomposer, the cleaning liquid inlet is connected with a nozzle, the nozzle can adopt any known form in the field, the cleaning liquid can be sprayed to the filter screen partition plate assembly at a high speed, the coverage area accounts for more than 70% of the area of the whole filter screen partition plate assembly, the washing and scouring effect on the filter screen partition plate assembly is realized, the nozzle is arranged at a certain inclination angle, the inclination direction faces towards the connecting channel, and the inclination angle and the vertical central line form 5-45 degrees, preferably 10-30 degrees.
In the hydrate decomposer, the liquid holding capacity of the cold clear liquid storage tank is 1/3-2/3 of the volume of the liquid storage tank.
In the hydrate decomposer, the liquid holding capacity of the regeneration liquid storage tank is 1/2-5/6 of the volume of the storage tank.
In the hydrate decomposer, a dividing wall type heat exchange device is arranged in the heat exchange unit, the hot fluid pipe running process heats the hydrate slurry in a coil pipe mode, and fins can be additionally arranged outside the coil pipe for strengthening heat exchange.
In the hydrate decomposer, a plurality of groups of baffle plates are arranged among the coil pipes of the heat exchange equipment in the decomposition unit, so that the functions of supporting the coil pipes and strengthening the heat exchange effect are achieved.
In the hydrate decomposer, the stripping gas inlet is connected with a gas distributor, the gas distributor and the cross section of the decomposition unit are uniformly distributed to the maximum extent, so that the stripping gas is in reverse flow contact with the hydrate-rich slurry in the decomposition unit, the gas distributor can adopt a gas distributor known in the art, and the stripping gas can be regenerated gas decomposed by the unit and can also be any gas which does not react with the subsequent processing process.
In the hydrate decomposer, a regenerated hydrate working solution outlet at the bottom of the decomposition unit is divided into two paths, one path is connected with the cleaning solution inlet through a pipeline, part of regenerated hydrate working solution discharged from the bottom of the decomposition unit is used as an internal circulation cleaning solution, and the volumetric flow rate of the regenerated hydrate working solution used as the internal circulation cleaning solution accounts for 1/5-1, preferably 1/3-1/2, of the volumetric flow rate of the total regenerated hydrate working solution.
In the process, the hydrate working solution is an aqueous solution added with an auxiliary agent, the auxiliary agent comprises an auxiliary agent A, the auxiliary agent A is one or more of Sodium Dodecyl Sulfate (SDS), Sodium Dodecyl Benzene Sulfonate (SDBS), linear alkyl sodium sulfonate (LAB-SA) and Alkyl Polyglycoside (APG), and the mass fraction of the auxiliary agent A is preferably 0.005-1.0%, and more preferably 0.01-0.5%.
In the process, an auxiliary B can be added into the hydrate working solution, the auxiliary B is one or more of kerosene, diesel oil and silicone oil, and the volume ratio of the addition amount of the auxiliary B to water in the hydrate working solution is 1/5-2/1, preferably 1/3-1/1. When the auxiliary agent B is added into the hydrate working solution, an emulsifier is preferably added, the selected emulsifier can be a hydrophilic emulsifier to form a water-in-oil (o/w) type emulsion or a lipophilic emulsifier to form an oil-in-water (w/o) type emulsion, and the addition amount of the emulsifier and the mole fraction of water in the hydrate working solution are 0.5-3%.
In the process, the hydrate working solution can also comprise an auxiliary agent C, wherein the auxiliary agent C is one or more of N-methyl pyrrolidone, propylene carbonate, sulfolane, N-formyl morpholine and polyethylene glycol, and the mass fraction of the auxiliary agent C is 2-30%, preferably 5-20%.
In the process of the present invention, the acid gas may be of various origins, preferably suitable for use as H260-95% of S and CO2The content is 5-40%, and the gas amount is 50-1000 Nm3Acid gas of small and medium-sized refineries.
In the process of the invention, the high concentration H is obtained after treatment by the separation unit2S gas, the stage number of the absorption reactor can be controlled according to the product requirement, and Na is produced by the S gas and the raw material alkali liquor2S or NaHS chemical products.
Compared with the prior art, the process and the device for separating the acid gas by the hydration method have the following advantages:
(1) the process organically combines environmental management and chemical production into an integrated process. Using different conditions of H2S gas and CO2The characteristic of large phase equilibrium difference when gas and water form hydrate is controlled by controlling the hydration condition to make H2The S gas and the hydrate working solution preferentially generate hydrate and enter a hydrate phase, CO2The gas is enriched and discharged in the gas phase without generating or generating little hydrate, thereby realizing the purpose of enriching and discharging H in the acid gas2S gas and CO2And (4) separating the gas. The whole process has mild operation conditions, good separation effect and high operation flexibility, and the treated acid gas can be divided into high-concentration CO2Gas (volume fraction > 80%) and high concentration of H2S gas (volume fraction > 95%); rich in H2The hydrate of S gas molecule is decomposed in the hydrate decomposer and released with high contentPurity H2S gas, alkaline absorption unit with high purity H2S gas is used as raw material and reacts with raw material alkali liquor to produce Na2S or NaHS chemical products. The whole treatment process is environment-friendly and reliable, and no waste residue, salt-containing wastewater and the like are generated.
(2) According to the invention, the adopted hydrate working solution is a multi-component compounded working solution and is conveyed in a hydrate slurry form, and through the compounding interaction among the auxiliary agent A, B, C, the gas-liquid interfacial tension can be reduced, the solubility and diffusion coefficient of gas in a liquid phase are increased, and the H ratio of the working solution to H is increased2The dissolving and absorbing capacity of S greatly promotes the generation of gas-formed hydrate in liquid phase, effectively improves the generation rate of hydrate, increases the gas storage density of hydrate, ensures the fluidity of hydrate phase, and improves H2S and CO2The continuous and stable operation of the device is ensured while the gas is separated.
(3) The process and the device of the invention reasonably optimize and fully utilize the energy of the whole acid gas treatment process. The surplus heat generated by the alkali liquor absorption method is fully used for decomposing the hydrate in the hydrate decomposer, and meanwhile, the product liquid after heat exchange flows back, so that the homogenization and control of the reaction temperature field of the absorption unit are realized, the system energy is reasonably utilized, and the energy consumption of the device is greatly reduced.
(4) The hydrate decomposer provided by the invention is provided with a slurry separation unit and a decomposition unit, and is used for filtering and separating hydrate slurry and deeply decomposing the hydrate slurry respectively. The slurry separation unit separates the hydrate slurry into a hydrate-rich phase and a cold clear liquid phase: the hydrate content in the cold clear liquid phase is extremely low, the temperature does not need to be raised, and the lower temperature can be maintained for recycling; the hydrate in the hydrate-rich phase accounts for more than 80 percent, the decomposition unit is heated and decomposed, the high-efficiency heat exchange and stripping means are matched to enhance the decomposition of the hydrate, and the leading-out part of the regenerated working solution is used for washing and scouring the filter screen partition plate assembly of the slurry separation unit. The decomposer with the mode can efficiently decompose hydrate slurry with fluidity, has high hydrate decomposition efficiency, self-cleaning function and easy maintenance, and greatly reduces the energy consumption of heating decomposition of the hydrate slurry and cooling and recycling of working solution after decomposition.
Drawings
FIG. 1 is a schematic diagram of the acid gas separation process and apparatus by the hydration method of the present invention.
FIG. 2 is a schematic structural diagram of a hydrate decomposer in the process and the device for separating acid gas by a hydration method.
Detailed Description
The method and apparatus for treating acid gas according to the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto.
As shown in fig. 2, the hydrate decomposer of the present invention comprises a slurry separation unit and a decomposition unit, which are communicated through a connecting passage 12; the slurry separation unit is divided into an upper part and a lower part by a filter screen partition plate assembly 5, the upper part is sequentially provided with a hydrate slurry inlet 1, a cleaning liquid inlet 3 and a connecting channel interface 19 from top to bottom, the lower part is a cold clear liquid storage tank 6, and the bottom of the storage tank is provided with a cold clear liquid outlet 13; the decomposition unit is sequentially provided with a hydrate decomposition gas outlet 11, a connecting channel interface 20 and a regenerated liquid storage tank 7 from top to bottom, and the regenerated liquid storage tank 7 is sequentially provided with a heat exchange unit 10, a stripping gas inlet 8 and a regenerated hydrate working liquid outlet 14 from top to bottom. Wherein the hydrate slurry inlet 1 of the separation unit is connected with a spraying assembly 2; the inner circulation cleaning liquid inlet 3 is connected with a cleaning nozzle 4; the stripping gas inlet 8 of the deep decomposition unit is connected with a stripping gas distributor 9; one end of the heat exchange device 10 is provided with a heat medium inlet 15, and the other end is provided with a heat medium outlet 16; and a plurality of groups of baffle plates 17 are arranged among the coil pipes of the heat exchange unit in the regeneration liquid storage tank 7.
The working process of the hydrate decomposer is as follows: the hydrate slurry is introduced into the decomposer through a hydrate slurry inlet 1 of the hydrate decomposer, the hydrate slurry is sprayed downwards through a spraying assembly 2, the sprayed hydrate slurry is filtered by a filter screen partition plate assembly 5 and is divided into a hydrate-rich phase and a cold clear liquid phase, a washing nozzle 4 above the filter screen partition plate assembly 5 realizes washing and scouring of the filter screen partition plate assembly 5 through continuous spraying of an internal circulation cleaning liquid, the filtered cold clear liquid falls to a cold clear liquid reservoir 6, the cold clear liquid circulates at a cold clear liquid outlet 13 at the bottom of the reservoir to be recycled to a hydrate reactor, the hydrate-rich phase enters a regeneration liquid reservoir 7 through a connecting channel 12, the hydrate-rich phase exchanges heat with a heat exchange device 10 in the regeneration liquid reservoir 7 and sequentially passes through a channel formed by a baffling baffle 17, the hydrate-rich phase is continuously heated and decomposed and releases gas in the falling process, and simultaneously, stripping gas is introduced into the bottom of the regeneration liquid reservoir 7 through a stripping gas inlet 8, the stripping gas is uniformly distributed by a stripping gas distributor 9 and then is in countercurrent contact with the hydrate slurry, the hydrate is decomposed to release high-concentration absorbed gas, the gas is finally discharged through a hydrate decomposition gas outlet 11, the decomposed regenerated hydrate working solution is discharged through a regenerated hydrate working solution outlet 14 at the bottom of a regenerated solution reservoir 7, part of the regenerated hydrate working solution 18 is used as an internal circulation washing solution and enters a slurry separation unit to wash the filter screen partition plate assembly 5, and the rest regenerated working solution is subjected to cooling treatment and then is conveyed to a hydrate reactor.
As shown in fig. 1, the present invention provides a device for separating acid gas by a hydration method, which comprises a hydration reactor 24, a hydrate decomposer 27, a cooler 29, an absorption reactor 33 and a product tank 40; an acid gas feed line 21 is connected with a gas phase inlet of a hydrate reactor 24 through a compressor 22; the liquid phase outlet of the hydration reactor 24 is connected with the hydrate slurry inlet of the hydrate decomposer 27 through a pipeline 26, and the gas phase outlet of the hydration reactor 24 is connected with a separation tail gas pipeline 25; a cold clear liquid outlet pipeline 28 and a regeneration working liquid outlet pipeline 31 of the hydrate decomposer 27 are connected with inlets of a heat exchange device 29, and an outlet of the heat exchange device 29 is connected with a liquid phase inlet of the hydration reactor 24 through a pipeline 30; the gas phase outlet at the top of the hydrate decomposer 27 is connected with the gas phase inlet of the absorption reactor 33 through a pipeline 32, and the stripping gas inlet at the bottom of the hydrate decomposer 27 is connected with a stripping gas pipeline 34; the gas phase outlet of the absorption reactor 33 is connected with a purified gas pipeline 35, the absorption reactor 33 is further connected with an alkali liquor supply pipeline 36, the liquid phase outlet pipeline 38 of the absorption reactor 33 is divided into two paths, the first path is connected with a product tank 40 through a pipeline 37, the second path is connected with the inlet of the heat exchange unit of the hydrate decomposer 27 through a pipeline 39, and the outlet of the heat exchange unit of the hydrate decomposer 27 is connected with the product liquid reflux inlet of the absorption reactor 33 through a pipeline 41.
The technological process for separating the acid gas by the hydration method comprises the following steps: the acid gas from the feed line 21 is pressurized by the compressor 22 and then fed into the hydration reactor 24 where H, which is susceptible to hydrate formation, is introduced into the hydration reactor 242S gas enters a hydrate phase (solid-liquid phase) to form slurry, and CO which is not easy to generate hydrate is not easy to generate2The gas is enriched in gas phase and discharged through a tail gas pipeline 25 to realize CO in the acid gas2Separation of (4). Enriching the hydration reactor 24 with H2The hydrate slurry of the S gas is introduced into a slurry separation unit of a hydrate decomposer 27 through a pipeline 26, the hydrate slurry enters through a hydrate slurry inlet 1 and is sprayed downwards through a spraying assembly 2, the sprayed hydrate slurry is filtered by a filter screen partition plate assembly 5 and is divided into a hydrate-rich phase and a cold clear liquid phase, a washing nozzle 4 above the filter screen partition plate assembly 5 realizes washing and scouring of the filter screen partition plate assembly 5 through continuously spraying an internal circulation cleaning liquid, the filtered cold clear liquid falls to a cold clear liquid reservoir 6, the hydrate-rich phase enters a regeneration liquid reservoir 7 through a connecting channel 12, the hydrate-rich phase exchanges heat with high-temperature product liquid of an absorption unit through a heat exchange device 10 in the regeneration liquid reservoir 7 and sequentially passes through a channel formed by a baffling baffle 17, the hydrate-rich phase is continuously heated and decomposed and releases gas in the falling process, simultaneously, stripping gas is introduced into the bottom of a regenerated liquid reservoir 7 through a stripping gas inlet 8, the stripping gas is uniformly distributed by a stripping gas distributor 9 and then is in countercurrent contact with hydrate slurry, and the hydrate is decomposed to release high-concentration H2S gas is discharged from bottom to top through a hydrate decomposition gas outlet 11, decomposed regeneration working liquid is discharged through a regeneration working liquid outlet 14 at the bottom of a regeneration liquid storage tank 7, part of regeneration working liquid 18 serving as internal circulation washing liquid enters a slurry separation unit to wash the filter screen partition plate assembly 5, the rest regeneration working liquid and cold clear liquid enter a heat exchange device 29 together to be cooled and then return to a hydration reactor 24 for recycling, and released H is discharged through a hydrate decomposition gas outlet 142S gas enters absorption reactor 33 through line 32 and comes fromThe alkali liquor in the alkali liquor pipeline 36 reacts, the residual exhaust gas obtained after the reaction treatment is discharged through the purified gas outlet pipeline 35, the product liquid obtained by the reaction is divided into two paths, the first path enters the product tank 40 for storage through the pipeline 37, the second path enters the hydrate decomposer 27 through the pipeline 39 to be used as a heat source for heating the hydrate, and the product liquid after heat exchange returns to the absorption reactor 33 through the pipeline 41.
Example 1
The amount of acid gas in a certain refinery is Q =400Nm3H, pressure 0.7MPa, where H2S volume fraction of 84%, CO2The volume fraction is 16%, and the rest is hydrocarbons and the like. The acid gas is treated by the treatment method and the treatment device shown in FIG. 1. Wherein, the hydrate decomposer adopts the decomposer structure shown in FIG. 2.
The operating conditions and treatment effects during the treatment were as follows: the acid gas 21 is pressurized to 1.2Mpa by a compressor 22 and then is introduced into a hydration reactor 24, and reacts with the hydrate working solution in the hydration reactor 24 under the following reaction conditions: the pressure is 1.2Mpa, the temperature is 5 ℃, the hydrate working solution is composed of water, SDS accounting for 0.03 percent of the mass fraction of the water solution, polyethylene glycol accounting for 10 percent of the mass fraction of the water solution, diesel oil accounting for 1/4 of the volume ratio of the diesel oil to the water, and span (dehydrated sorbitol fatty acid ester) emulsifier accounting for 0.8 percent of the molar ratio of the span to the water, the generation amount of the hydrate is controlled to be about 60 percent of the total volume amount of the hydrate slurry through reaction, and H in a hydration reactor 242S gas preferentially forms hydrate with the working fluid to be enriched into hydrate phase, CO2And the inert gas is enriched in gas phase and discharged as tail gas, and CO in the tail gas2The concentration is about 85 percent, and the concentrated treatment is carried out by the refinery gas desulfurization system which is incorporated into the upstream of the refinery acid gas; conveying the hydrate slurry 26 to a hydrate decomposer 27, wherein the condition of the hydrate decomposer 27 is that the pressure is 0.5Mpa, the hydrate slurry 6 is separated into a hydrate-rich phase accounting for 70 percent of the total slurry amount and a cold clear liquid phase accounting for 30 percent of the total slurry amount in a slurry separation unit, wherein the hydrate content in the cold clear liquid is about 10 percent and enters a cold clear liquid storage tank, the hydrate content in the hydrate-rich phase is higher than 80 percent and enters a regeneration liquid storage tank 7 of the decomposition unit, the regeneration liquid storage tank 7 maintains the temperature at about 22 ℃ by adjusting the liquid flow rate of a high-temperature product, and the hydrate-rich slurry is released after being heatedTo produce high concentration H2S gas and regenerated working liquid are obtained at the same time, the regenerated working liquid and cold clear liquid enter a heat exchange device 29 together to be cooled and then return to the hydration reactor 24 for recycling, nitrogen is adopted as stripping gas at the bottom of a regenerated liquid storage tank 7, and CO in gas released from a hydrate decomposer2The content is less than 3 percent; the obtained high concentration H2The S gas enters an absorption reactor 33 to react with 48 percent NaOH solution to generate Na2S product, the operation conditions of the absorption reactor are as follows: absorbing the purified tail gas discharged after being treated by the reactor 33 at the pressure of 0.4Mpa and the temperature of 95 ℃ to obtain Na2And a part of the S product liquid is led out to enter the hydrate decomposer 7 for heating, the S product liquid is used as internal circulation liquid to return to the absorption reactor 33 after heat exchange, and the rest product liquid enters the product tank 40 for storage. The process for treating the refinery acid gas not only realizes the purification treatment of the acid gas, but also produces Na2And the S product changes the acidic gas into valuable, improves the added value of the product, and converts environmental management into a production process of chemical products. The process is economical and efficient for containing CO2And H2The acid gas of S is pretreated to ensure the good fluidity of hydrate in the separation unit of the hydration method and control Na of the absorption unit of the alkaline method2CO3 / NaHCO3Content, ensuring continuous and long-period stable operation of the device. In addition, the energy in the whole process is fully utilized through flow optimization and the hydrate decomposer, and the energy consumption is greatly reduced.
Comparative example 1
The method is the same as that in the embodiment 1, except that the hydrate decomposer adopts a conventional single-tower form, when the same treatment effect is achieved, because the double-tower hierarchical decomposer adopted in the embodiment 1 decomposes the hydrate slurry into a 70% hydrate-rich phase and a 30% cold clear liquid phase through the separation unit, and then only the hydrate-rich phase accounting for 70% of the total slurry is subjected to deep decomposition treatment, while the conventional decomposer adopted in the comparative example needs to integrally heat the hydrate and the solution which does not react to generate the hydrate, and integrally cool the regenerated liquid obtained after decomposing the released gas, so that the energy consumption is greatly increased, and the operation cost is increased. Compared with the embodiment 1, the total energy consumption of the working solution for cooling after the hydrate slurry is heated and decomposed and the working solution is decomposed in the comparative example is increased by more than 40%.
Comparative example 2
The method is the same as the example 1, except that the acid gas is pretreated by adopting the traditional absorption-regeneration process of an alcohol amine method, the absorption liquid adopts MDEA solution with the mass fraction of 30%, the absorption temperature is 30 ℃, and the regeneration temperature is 118 ℃. When the same treatment effect is achieved, the energy consumption is larger due to the higher regeneration temperature of the amine liquid, the heat for decomposing the hydrate in the example 1 can be completely provided by the reaction heat generated by the alkali method, and compared with the example 1, the energy consumption for the pretreatment of the acid gas in the comparative example is increased by more than 20%.

Claims (53)

1. A hydration process acid gas separation plant comprising a hydration reactor, a hydrate decomposer, an absorption reactor and a product tank; the acid gas feeding pipeline is connected with a gas phase inlet of the hydration reactor, a liquid phase outlet of the hydration reactor is connected with a hydrate slurry inlet of a slurry separation unit of the hydrate decomposer, and a cold clear liquid outlet and a regenerated hydrate working liquid outlet of the hydrate decomposer are connected with a liquid phase inlet of the hydrate reactor after passing through a cooler; a gas phase outlet at the top of the hydrate decomposer is connected with a gas phase inlet of the absorption reactor, a gas phase outlet of the absorption reactor is connected with a purified gas outlet pipeline, a liquid phase outlet of the absorption reactor is divided into two paths, the first path is connected with the product tank, the second path is connected with a circulating liquid inlet of the absorption reactor through heat exchange equipment in the hydrate decomposer, and a liquid phase inlet of the absorption reactor is connected with an alkali liquor inlet pipeline; the hydrate decomposer comprises a slurry separation unit and a decomposition unit, and the slurry separation unit is communicated with the decomposition unit through a connecting channel; the slurry separation unit is divided into an upper part and a lower part by a filter screen partition plate assembly, the upper part is sequentially provided with a hydrate slurry inlet, a cleaning liquid inlet and a connecting channel interface from top to bottom, the lower part is a cold clear liquid storage tank, and the bottom of the storage tank is provided with a cold clear liquid outlet; the decomposition unit is sequentially provided with a hydrate decomposition gas outlet, a connecting channel interface and a regeneration liquid storage tank from top to bottom, and the regeneration liquid storage tank is internally provided with a heat exchange unit, a stripping gas inlet and a regenerated hydrate working liquid outlet.
2. The apparatus for the separation of acid gases by hydration of claim 1 where the acid gas feed line is provided with a compressor to ensure that the acid gas pressure matches the hydration reactor operating pressure.
3. The apparatus for the separation of acid gases by the hydration process of claim 1 wherein the absorption reactor is a gas-liquid mass transfer reaction device.
4. The apparatus for the hydration of claim 1 or 3, wherein the absorption reactor is one of a bubble column reactor, a packed column reactor, an impinging stream reactor, a rotating bed reactor, and a venturi reactor.
5. The apparatus for the separation of acid gases by the hydration process of claim 1 or 3 wherein the absorption reactor is a rotating bed reactor.
6. The apparatus for separating acid gas according to the hydration method of claim 1, wherein the connecting channel of the hydrate decomposer is horizontally arranged or is obliquely arranged at an angle, when the connecting channel is obliquely arranged, the connecting channel interface of the slurry separation unit is higher than the connecting channel interface of the decomposition unit, and the angle of inclination is 10-60 degrees with the horizontal plane.
7. The apparatus for separating acid gas by hydration method according to claim 1 or 6, wherein the connecting channel in the hydrate decomposer is horizontally arranged or obliquely arranged at an angle, when the connecting channel is obliquely arranged, the connecting channel interface of the slurry separation unit is higher than the connecting channel interface of the decomposition unit, and the angle of inclination is 15-45 degrees with the horizontal plane.
8. The apparatus for the separation of acid gases by the hydration process of claim 1 wherein the lower plane of the connecting passage in the hydrate decomposer is positioned between 1/2 and 3/4 of the vertical height of the slurry separation unit.
9. The apparatus for separating acid gas according to the hydration method of claim 1, wherein the screen separator plate assembly in the hydrate decomposer is horizontally arranged or is obliquely arranged at a certain angle, and the upper plane of the screen separator plate assembly and the lower plane of the connecting channel are arranged in the same plane.
10. The device for separating acid gas by the hydration method according to claim 1, wherein the liquid holding capacity of a cold clear liquid storage tank in the hydrate decomposer is 1/3-2/3 of the volume of the storage tank.
11. The device for separating acid gas by the hydration method according to claim 1 or 10, wherein the liquid holding capacity of a regeneration liquid storage tank in the hydrate decomposer is 1/2-5/6 of the volume of the storage tank.
12. The apparatus for separating acid gas by hydration method according to claim 1, wherein a dividing wall type heat exchange device is arranged in the heat exchange unit in the hydrate decomposer, and the hot fluid pipe-moving process heats the hydrate slurry in a coil form.
13. The apparatus for separating acid gas by hydration method according to claim 1, wherein, a plurality of groups of baffle plates are arranged between the coil pipes of the heat exchange device in the decomposition unit in the hydrate decomposer.
14. The acid gas separation device by the hydration method according to claim 1, wherein a regenerated hydrate working solution outlet at the bottom of the decomposition unit in the hydrate decomposer is divided into two paths, one path is connected with the cleaning solution inlet through a pipeline, the regenerated hydrate working solution discharged from the bottom of a part of the decomposition unit is used as an internal circulation cleaning solution, and the volumetric flow of the regenerated hydrate working solution used as the internal circulation cleaning solution accounts for 1/5-1 of the volumetric flow of the total regenerated hydrate working solution.
15. The acid gas separation device by the hydration method according to claim 1 or 14, wherein a regenerated hydrate working solution outlet at the bottom of the decomposition unit in the hydrate decomposer is divided into two paths, one path is connected with the cleaning solution inlet through a pipeline, the regenerated hydrate working solution discharged from the bottom of the partial decomposition unit is used as an internal circulation cleaning solution, and the volumetric flow of the regenerated hydrate working solution used as the internal circulation cleaning solution accounts for 1/3-1/2 of the volumetric flow of the total regenerated hydrate working solution.
16. A process for separating acid gas by a hydration method, which comprises the following steps:
(1) the raw material acid gas enters a hydration reactor to react with hydrate working solution, and H in the acid gas2S gas reacts with the hydrate working solution and enters the hydrate phase to form hydrate slurry, CO2Enriching in the gas phase and discharging out of the hydration reactor;
(2) h-enriched fraction obtained in step (1)2The hydrate slurry of the S gas enters a hydrate decomposer, cold clear liquid and hydrate-rich phase slurry are obtained after the treatment of a slurry separation unit of the hydrate decomposer, and the cold clear liquid enters a cold clear liquid storage tank below;
(3) the hydrate-rich phase slurry obtained in the step (2) enters a decomposition unit under the action of a cleaning solution, exchanges heat with product liquid from an absorption reactor in a regenerated liquid storage tank, and is in countercurrent contact with stripping gas introduced from the bottom of the decomposition unit to decompose and release H2S, decomposing the gas and the hydrate to obtain regenerated working solution, mixing the regenerated hydrate working solution with the cold clear solution, cooling, and returning to the hydration reactor for recycling;
(4) h obtained in step (3)2The S gas enters an absorption reactor to react with alkali liquor, the treated tail gas is discharged, the obtained product liquid is divided into two paths, the first path enters a hydrate decomposer to be used as a heat source for heat exchange and then returns to the absorption reactor, and the second path enters a product tank;
the hydrate decomposer adopts a hydrate decomposer with the following structure, the hydrate decomposer comprises a slurry separation unit and a decomposition unit, and the slurry separation unit is communicated with the decomposition unit through a connecting channel; the slurry separation unit is divided into an upper part and a lower part by a filter screen partition plate assembly, the upper part is sequentially provided with a hydrate slurry inlet, a cleaning liquid inlet and a connecting channel interface from top to bottom, the lower part is a cold clear liquid storage tank, and the bottom of the storage tank is provided with a cold clear liquid outlet; the decomposition unit is sequentially provided with a hydrate decomposition gas outlet, a connecting channel interface and a regeneration liquid storage tank from top to bottom, and the regeneration liquid storage tank is sequentially provided with a heat exchange unit, a stripping gas inlet and a regenerated hydrate working liquid outlet from top to bottom.
17. The process as claimed in claim 16, wherein the pressure of the acid gas in the step (1) is matched with the operation pressure of the hydration reactor, the pressure of the acid gas is 0.1Mpa to 3.0Mpa, and when the pressure of the acid gas is insufficient, pressurization is performed by a compressor.
18. The process according to claim 16 or 17, wherein the pressure of the acid gas in the step (1) is matched with the operation pressure of the hydration reactor, the pressure of the acid gas is 0.3Mpa to 1.5Mpa, and when the pressure of the acid gas is insufficient, pressurization is performed by a compressor.
19. The process according to claim 16, wherein the volume ratio of the hydrate working solution used in the step (1) to the acid gas is 5-100L/m3。
20. The process according to claim 16 or 19, wherein the volume ratio of the hydrate working solution used in the step (1) to the acid gas is 10-50L/m3。
21. The process of claim 16 wherein the hydration reactor is operated at conditions of: the pressure is 0.1-3.0 Mpa, and the temperature is 0-15 ℃.
22. A process according to claim 16 or 21, wherein the hydration reactor is operated at conditions such that: the pressure is 0.3 Mpa-1.5 Mpa, and the temperature is 3-10 ℃.
23. The process according to claim 16, wherein in the hydration reactor in the step (1), hydrate slurry refers to a mixed solution of formed hydrate and unreacted hydrate working solution, and the volume ratio of the hydrate in the hydrate slurry is controlled by the reaction to be 30-80%.
24. The process according to claim 16 or 23, wherein in the hydration reactor in the step (1), hydrate slurry refers to a mixed solution of formed hydrate and unreacted generated hydration working solution, and the volume ratio of the hydrate in the hydrate slurry is controlled by the reaction to be 50-70%.
25. The process according to claim 16, wherein the operating conditions of the hydrate decomposer in the step (2) are as follows: the pressure is 0.02 Mpa-2.0 Mpa, and the temperature of the slurry separation unit is 0-10 ℃.
26. The process according to claim 16 or 25, wherein the operating conditions of the hydrate decomposer in the step (2) are as follows: the pressure is 0.05 Mpa-1.0 Mpa, and the temperature of the slurry separation unit is 10-40 ℃.
27. The process according to claim 16, wherein said stripping gas of step (3) is any gas that does not react with subsequent processing.
28. The process according to claim 16 or 27, wherein the stripping gas in step (3) is nitrogen or an inert gas.
29. The process according to claim 16, wherein said stripping gas of step (3) is a decomposition gas obtained from a decomposition unit.
30. The process according to claim 16, wherein the regenerated hydrate working solution and the cold clear solution in the step (3) are cooled, the temperature of the cooled regenerated hydrate working solution and the cooled clear solution is controlled to be 0-15 ℃, and the cooled regenerated hydrate working solution and the cooled clear solution are returned to the hydration reactor for recycling.
31. The process according to claim 16 or 30, wherein the regenerated hydrate working solution and the cold clear solution in the step (3) are cooled, the temperature of the cooled regenerated hydrate working solution and the cooled clear solution is controlled to be 3-10 ℃, and the cooled regenerated hydrate working solution and the cold clear solution are returned to the hydration reactor for recycling.
32. The process according to claim 16, wherein the absorption reactor operating conditions are: the pressure is 0.02 Mpa-2.0 Mpa, and the temperature is 70-95 ℃.
33. The process according to claim 16 or 32, wherein the absorption reactor operating conditions are: the pressure is 0.1-1.0 Mpa, and the temperature is 80-90 ℃.
34. The process of claim 16, wherein the alkali solution is NaOH solution, and the mass concentration of the alkali solution is 20-60%.
35. The process as claimed in claim 16 or 34, wherein the alkali solution is NaOH solution with mass concentration of 32-48%.
36. The process according to claim 16, wherein the product liquid obtained by the reaction in the absorption reactor in the step (4) is divided into two paths, the first path enters the hydrate decomposer to be used as a heat source, the second path enters the product tank, and the flow rate ratio of the product liquid of the first path to the product liquid of the second path is 20/1-1/1.
37. The process according to claim 16 or 36, wherein the product liquid obtained by the reaction in the absorption reactor in the step (4) is divided into two paths, the first path enters the hydrate decomposer to be used as a heat source, the second path enters the product tank, and the flow rate ratio of the product liquid of the first path to the product liquid of the second path is 10/1-2/1.
38. The process according to claim 16, wherein the connecting channel is horizontally arranged or is obliquely arranged at an angle, when obliquely arranged, the slurry separation unit connecting channel interface is higher than the decomposition unit connecting channel interface, and the angle of inclination is 10-60 ° to the horizontal plane.
39. A process according to claim 16 or 38, wherein the connecting channel is arranged horizontally or inclined at an angle such that the slurry separation unit connecting channel interface is higher than the decomposition unit connecting channel interface and the angle of inclination is between 15 ° and 45 ° to the horizontal.
40. The process of claim 16 wherein said screen spacer assembly is disposed horizontally or at an angle inclined such that the upper plane of the screen spacer assembly remains coplanar with the lower plane of the connecting channel.
41. The process according to claim 16, wherein the liquid hold-up of the chilled clear liquid reservoir is 1/3-2/3 of the reservoir volume.
42. The process according to claim 16 wherein the regeneration fluid reservoir liquid hold up is 1/2 to 5/6 of the reservoir volume.
43. The process according to claim 16, wherein a dividing wall type heat exchange device is arranged in the heat exchange unit, and the hot fluid pipe-moving process heats the hydrate slurry in a coil form.
44. The process according to claim 16, wherein a plurality of sets of baffle plates are arranged between the coils of the heat exchange device in the decomposition unit.
45. The process according to claim 16, wherein a regenerated hydrate working solution outlet at the bottom of the decomposition unit is divided into two paths, one path is connected with the cleaning solution inlet through a pipeline, the regenerated hydrate working solution discharged from the bottom of part of the decomposition unit is used as an internal circulation cleaning solution, and the volumetric flow of the regenerated hydrate working solution used as the internal circulation cleaning solution accounts for 1/5-1 of the volumetric flow of the total regenerated hydrate working solution.
46. The process as claimed in claim 16 or 45, wherein the regenerated hydrate working solution outlet at the bottom of the decomposition unit is divided into two paths, one path is connected with the cleaning solution inlet through a pipeline, the regenerated hydrate working solution discharged from the bottom of the partial decomposition unit is used as an internal circulation cleaning solution, and the volumetric flow rate of the regenerated hydrate working solution used as the internal circulation cleaning solution accounts for 1/3-1/2 of the volumetric flow rate of the total regenerated hydrate working solution.
47. The process of claim 16, wherein the hydrate working solution is an aqueous solution added with an auxiliary agent, the auxiliary agent comprises an auxiliary agent A, and the auxiliary agent A is one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, linear alkyl sodium sulfonate and alkyl polyglycoside, and the mass fraction of the auxiliary agent A is 0.005-1.0%.
48. The process of claim 16 or 47, wherein the hydrate working solution is an aqueous solution added with an auxiliary agent, the auxiliary agent comprises an auxiliary agent A, and the auxiliary agent A is one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, linear alkyl sodium sulfonate and alkyl polyglycoside, and the mass fraction of the auxiliary agent A is 0.01-0.5%.
49. The process of claim 47, wherein an auxiliary B is added into the hydrate working solution, the auxiliary B is one or more of kerosene, diesel oil and silicone oil, and the volume ratio of the addition amount of the auxiliary B to water in the hydrate working solution is 1/5-2/1.
50. The process of claim 47 or 49, wherein an auxiliary B is added into the hydrate working solution, the auxiliary B is one or more of kerosene, diesel oil and silicone oil, and the volume ratio of the addition amount of the auxiliary B to water in the hydrate working solution is 1/3-1/1.
51. The process of claim 49, wherein an emulsifier is added when adjuvant B is added to the hydrate working fluid, the emulsifier is selected from a hydrophilic emulsifier to form a water-in-oil (o/w) type emulsion, or a lipophilic emulsifier to form an oil-in-water (w/o) type emulsion, and the emulsifier is added in a molar ratio of 0.5% to 3% based on the water in the hydrate working fluid.
52. The process of claim 51, wherein the hydrate working solution comprises an additive C, the additive C is one or more of N-methylpyrrolidone, propylene carbonate, sulfolane, N-formylmorpholine and polyethylene glycol, and the mass fraction of the additive C is 2-30%.
53. The process of claim 51, wherein the hydrate working solution comprises an additive C, the additive C is one or more of N-methylpyrrolidone, propylene carbonate, sulfolane, N-formylmorpholine and polyethylene glycol, and the mass fraction of the additive C is 5-20%.
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