CN113646062B - Tail gas treatment method - Google Patents

Tail gas treatment method Download PDF

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CN113646062B
CN113646062B CN202180002105.9A CN202180002105A CN113646062B CN 113646062 B CN113646062 B CN 113646062B CN 202180002105 A CN202180002105 A CN 202180002105A CN 113646062 B CN113646062 B CN 113646062B
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tail gas
ionic liquid
tower
regeneration
hcl
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CN113646062A (en
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杨志健
陈永乐
陈宇涵
刘建
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Anhui Jinhe Industrial Co Ltd
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Anhui Jinhe Industrial Co Ltd
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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
    • B01D53/002—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 by condensation
    • 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
    • B01D53/02—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 by adsorption, e.g. preparative gas chromatography
    • 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
    • B01D53/14—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 by absorption
    • B01D53/1418—Recovery of products
    • 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
    • B01D53/14—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 by absorption
    • B01D53/1425—Regeneration of liquid absorbents
    • 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
    • B01D53/14—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 by absorption
    • B01D53/1456—Removing acid components
    • 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
    • B01D53/14—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 by absorption
    • B01D53/18—Absorbing units; Liquid distributors therefor

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  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
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Abstract

The application provides a tail gas treatment method, wherein the tail gas is generated in the process of generating sucralose-6-ester through chlorination reaction of sucrose-6-ester, and the method comprises the following steps: cooling and condensing the tail gas to remove part of organic solvent and water to obtain a first solution and a first tail gas; adsorbing and separating the first tail gas by using hydrophilic ionic liquid to remove most of water and organic solvent in the first tail gas to obtain second tail gas; adsorbing and filtering the second tail gas by using a solid adsorbent to obtain a gaseous mixture, and separating the gaseous mixture to obtain gaseous hydrogen chloride and liquid sulfur dioxide; and introducing gaseous hydrogen chloride into water to obtain hydrochloric acid. The method takes ionic liquid adsorption as a main part, is organically combined with condensation, rectification and other means, can effectively treat chlorinated tail gas in the sucralose production process, and realizes HCl and SO 2 The effective separation of two gases to obtain high-quality hydrochloric acid and liquid SO 2 The product has simple process and low cost.

Description

Tail gas treatment method
Technical Field
The invention belongs to the technical field of chemical tail gas separation and recovery industry, and particularly relates to a tail gas treatment method.
Background
Sucralose-6-ester is one of important intermediates in the preparation of sucralose, sucrose-6-ester can be obtained by esterifying sucrose and then chlorinating with a chlorinating agent, at present, industrial chlorinating agents mainly comprise Vilsmeier (Vilsmeier) chlorinating agents and phosgene products, and due to the high risk and high pollution of phosgene, few enterprises are used. The Vilsmeier chlorinated reagent is mainly prepared from DMF and dimethyl sulfoxide, and is safer to use. However, in the chlorination process, a large amount of tail gas is generated, which contains HCl and SO 2 Water, DMF and trichloroethane.
The traditional treatment of the tail gas generally adopts cooling condensation and sulfurAcid dehydration, activated carbon adsorption and the like, but the operations are not enough to remove all organic matters and water in the tail gas, SO that on one hand, a large amount of organic/inorganic solids are generated in the subsequent pressure rectification process and are attached to the surfaces of flow-through materials such as pipe walls, delivery pumps and the like, serious equipment corrosion and blockage are caused, and HCl and SO are greatly limited 2 Recovering; HCl and SO on the other hand 2 Cannot be separated completely, such as hydrochloric acid obtained by direct water adsorption of HCl and containing large amount of SO 2 Gas, SO 2 The gas will form H in water 2 SO 3 Due to H 2 SO 3 Easily decomposed by heating to generate a large amount of SO 2 Gas, which causes the contact of the recovered hydrochloric acid product with alkali in the use process, can generate gas emulsification, and seriously affects the quality of the hydrochloric acid product.
There are also some differences from the conventional techniques regarding the inclusion of HCl and SO 2 For example, chinese patent CN103113197 reports a method for preparing trimethyl orthoacetate by reacting chlorinated tail gas with alcohol and acetonitrile, which solves the problem of HCl treatment and provides a raw material for sucrose esterification; however, the trimethyl orthoacetate esterification process is rarely adopted at present, and a large amount of waste salt and waste water are easily generated in the process, so that the method has no great practical value.
Chinese patent CN208511908 adopts low-temperature condensation to separate HCl and SO 2 The method of mixing the gases utilizes the difference of boiling points of the gases and the gas in SO 2 Blowing air into the product to carry HCl out, thereby increasing SO 2 And (4) the purity of the product. The method is used for separating two gases by simply using different boiling points, but the energy consumption is much higher than that of other methods, and the purity of the obtained product is not good; furthermore, the chlorinated off-gas generated in the sucralose process is not suitable for use in the case of aqueous, solvent-containing processes.
Chinese patent CN108373139 also adopts a cooling separation method to separate HCl and SO on the basis of removing water and solvent from sucralose chlorination tail gas 2 . The method uses concentrated sulfuric acid to remove water, so that the water removing effect is good, but the subsequent waste acid regeneration or treatment is troublesome;the organic matters cannot be completely removed by only collecting in a condensation way in the organic matter separation process, SO the obtained HCl and SO 2 The product purity is not high.
As another example, chinese patent CN103466550 reports a D-acid esterification tail gas recovery system in amoxicillin production process, and the tail gas system mainly contains HCl and SO 2 A gas. The method adopts a pressurized rectification mode to separate two gases, and adopts a triple pressurized rectification tower to separate the gases and organic matters; however, the system contains no moisture, so the requirements on system equipment are relatively low; however, a lot of moisture is generated in the sucrose chlorination reaction, and the method has great test on a separation method and equipment of a system, and is not suitable for being used in waste gas generated in the sucrose chlorination reaction.
Disclosure of Invention
In view of the current situation of processing tail gas generated in the process of chlorinating sucrose by adopting a Vilsmeier chlorinating agent to generate sucralose-6-ester, the problems of poor separation effect, difficult post-processing, easy severe equipment corrosion, pipeline blockage caused by solid attachments formed by compressed gas and the like exist, and the tail gas processing method is provided and can overcome the problems or at least partially solve the problems.
According to a first aspect of the present application, there is provided a method for treating tail gas generated in a process of chlorination of sucrose-6-ester to produce sucralose-6-ester, the method comprising:
a condensation step: cooling and condensing the tail gas to remove part of the organic solvent and part of water to obtain a first solution and a first tail gas;
a removing step: adsorbing and separating the first tail gas by using hydrophilic ionic liquid to remove most of water and part of organic solvent in the first tail gas to obtain second tail gas;
a separation step: adsorbing and filtering the second tail gas by using a solid adsorbent to obtain a gaseous mixture, and separating the gaseous mixture to obtain gaseous hydrogen chloride and liquid sulfur dioxide; and
phase inversion step: and introducing gaseous hydrogen chloride into water to obtain hydrochloric acid.
Optionally, the method further includes:
a first regeneration step included in the removal step: carrying out regeneration treatment on the hydrophilic ionic liquid used in the removing step to obtain regenerated hydrophilic ionic liquid and first regenerated tail gas; and
and recovering the regenerated hydrophilic ionic liquid for use in the removal step.
Optionally, in the above method, the regeneration temperature of the hydrophilic ionic liquid is 80-120 ℃, and the regeneration vacuum degree is-0.1 to-0.05 MPa.
Optionally, the method further includes:
a recovery step after the first regeneration step: absorbing the first regenerated tail gas by using lipophilic ionic liquid to remove organic components to obtain third tail gas;
absorbing the third tail gas by adopting a saturated sodium chloride aqueous solution to absorb hydrogen chloride to obtain a fourth tail gas;
recovering the fourth tail gas into the first tail gas to be subjected to the removal step;
carrying out hydrogen chloride regeneration treatment on the obtained saturated sodium chloride aqueous solution adsorbed with the hydrogen chloride to obtain regenerated hydrogen chloride, and recovering the regenerated hydrogen chloride into the hydrogen chloride to be subjected to the phase conversion step; the saturated aqueous sodium chloride solution from which hydrogen chloride was released was recovered to a saturated aqueous sodium chloride solution.
Optionally, the method further includes:
a second regeneration step after the recovery step: carrying out regeneration treatment on the oleophylic ionic liquid used in the recovery step to obtain regenerated oleophylic ionic liquid and fifth tail gas;
recovering the regenerated oleophilic ionic liquid for use in the recovering step;
and carrying out solvent recovery treatment on the fifth tail gas.
Optionally, in the above method, the regeneration temperature of the oleophilic ionic liquid is 80-120 ℃, and the regeneration vacuum degree is-0.1 to-0.05 MPa.
Optionally, in the above method, in the recovering step, the lipophilic ionic liquid is dibutyl 1-ethyl-3-methylimidazolium phosphate and/or dibutyl 1-butyl-3-methylimidazolium phosphate;
the method for adsorbing the first regenerated tail gas by adopting the oleophylic ionic liquid comprises the following steps:
and absorbing the first regenerated tail gas by using oleophylic ionic liquid at the temperature of 20-40 ℃.
Optionally, in the above method, in the condensing step, the temperature of the reduced-temperature condensation is set to 0 to 30 ℃.
Optionally, in the above method, the hydrophilic ionic liquid is one or more of pyridine hydrogen sulfate, methyl imidazole hydrogen sulfate and ethyl imidazole hydrogen sulfate.
Optionally, in the above method, the adsorbing the first exhaust gas with the hydrophilic ionic liquid includes:
and adsorbing the first tail gas by using hydrophilic ionic liquid at the temperature of 20-50 ℃.
The beneficial effects of this application lie in, utilize the impurity in the ionic liquid absorption chlorination tail gas, before the pressurization rectification, effectively solved water and organic matter to HCl and SO 2 The influence of the separation of the two gases solves the problems of serious corrosion and blockage caused by the adhesion of organic/inorganic solids on the pipe wall and a delivery pump generated in the process of pressure separation, and can obtain high-purity liquid SO 2 A product; the ionic liquid has extremely low corrosivity, and the ionic liquid is adopted to replace concentrated sulfuric acid, so that the problems of equipment corrosion and subsequent treatment caused by concentrated sulfuric acid dehydration in the traditional technology can be effectively solved; in addition, the ionic liquid has high reproducibility and simple regeneration process, and the cost of tail gas treatment is greatly reduced. The method takes the ionic liquid adsorption as the main part, is organically combined with condensation, rectification and other means, can effectively treat the chlorinated tail gas in the sucralose production process, and realizes HCl and SO 2 The effective separation of two gases to obtain high-quality hydrochloric acid and liquid SO 2 The product has simple integral treatment process and low cost and has great economic and application values.
The foregoing description is only an overview of the technical solutions of the present application, and the present application can be implemented according to the content of the description in order to make the technical means of the present application more clearly understood, and the following detailed description of the present application is given in order to make the above and other objects, features, and advantages of the present application more clearly understandable.
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The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
FIG. 1 shows a schematic flow diagram of a method for treating exhaust gas according to an embodiment of the present application;
fig. 2 shows a schematic structural diagram of an exhaust gas treatment device according to an embodiment of the present application.
Detailed Description
Exemplary embodiments of the present application will be described in more detail below. While exemplary embodiments of the present application have been illustrated, it should be understood that the present application may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The Ionic liquid is also called Room Temperature Ionic Liquids (RTILs for short), and is a green solvent and catalyst which are in great concern. The organic molten salt is a liquid organic molten salt with the melting point lower than 100 ℃, and because the organic molten salt is completely composed of anions and cations, the organic molten salt has many properties different from the conventional organic solvent, such as zero vapor pressure, high thermal stability, strong dissolving capacity, designable structure and function, and the like, and has great application potential in the fields of organic reaction, liquid phase separation, gas absorption, electrochemistry, and the like.
In the prior art, the treatment of tail gas generated in the process of chlorinating sucrose by adopting a Vilsmeier chlorinated reagent to generate sucralose-6-ester, referred to as chlorinated tail gas for short, has the problems of poor separation effect, easy severe equipment corrosion, pipeline blockage caused by the formation of solid attachments by compressed gas and the like.
This application introduces ionic liquid into the processing of chlorination tail gas, through moisture and organic impurity in the ionic liquid absorption tail gas to combine techniques such as condensation and pressurization rectification, effectively overcome prior art's not enough.
Fig. 1 shows a schematic flow chart of a tail gas treatment method according to an embodiment of the present application, and as can be seen from fig. 1, the present application at least includes steps S110 to S140:
a condensation step S110: and cooling and condensing the tail gas to remove part of the organic solvent and water to obtain a first solution and a first tail gas.
The tail gas of the application refers to the chlorination reaction of sucrose-6-ester and a chlorinating agent, such as Vilsmeier reagent and the like, which is generated in the chlorination process for generating the sucralose-6-ester and mainly contains gaseous water, HCl and SO 2 And organic solvents such as DMF and trichloroethane. At present, the mainstream technology for treating the tail gas generally adopts the traditional process of cooling condensation, concentrated sulfuric acid dehydration, activated carbon desolvation, pressurized rectification and separation, and the process has the following technical defects: the adoption of the dehydration mode of concentrated sulfuric acid can easily cause serious equipment corrosion, the solvent is easy to carbonize, and the concentrated sulfuric acid is not easy to regenerate after absorbing water; traditional condensation and activated carbon adsorption cannot completely remove high-concentration organic matters contained in gas, which can lead to the enrichment of organic matters in HCl and SO in the subsequent compression process 2 In the presence of the solid particles, the solid particles adhere to the pipe wall or the valve, block the pipeline and the like.
In this application, first, the above-mentioned tail gas is cooled and condensed, and in this process, most of the gaseous water will be converted into liquid water, gaseous DMF and gaseous organic solvents such as gaseous trichloromethane, and will be converted into liquid, and will be noted as the first solution, and the first tail gas is noted as the gaseous mixture by-pass with the gaseous mixture.
After cooling and condensation, the first solution mainly contains liquid water, DMF and trichloroethane, and the first solution can be used for solvent recovery treatment. The first tail gas comprises gaseous hydrogen chloride and SO 2 And partially gaseous water, small amounts of gaseous DMF and gaseous trichloromethane.
In some embodiments of the present application, in the condensation step, the temperature to which the reduced-temperature condensation is reduced is not limited, and is lower than the temperature of the chlorination reaction of sucrose-6 ester with the chlorinating agent; in other embodiments, the reduced temperature condensing temperature may be set to 0-30 ℃ for economic and effective reasons.
A removal step S120: adsorbing the first tail gas by using hydrophilic ionic liquid to remove most of water and organic solvent in the first tail gas to obtain second tail gas;
in the condensation step, the content of the organic solvent is reduced to be very low, the content is very little, the moisture content is relatively much, the hydrophilic ionic liquid is selected to adsorb the first tail gas in the step, because the hydrophilic ionic liquid has very strong adsorption to the moisture, and has certain adsorption effect to the organic solvent, after the hydrophilic ionic liquid is adopted to adsorb the first tail gas, the moisture is basically eliminated completely, and the content of the organic solvent is also very low.
Gaseous HCl and gaseous SO 2 The solubility in the ionic liquid is very low, SO that the ionic liquid is adopted to adsorb the tail gas, and water, an organic solvent, HCl and SO can be effectively separated 2 。
Separation step S130: and (3) adsorbing and filtering the second tail gas by adopting a solid adsorbent to obtain a first gaseous mixture, and separating the first gaseous mixture to obtain gaseous hydrogen chloride and liquid sulfur dioxide.
In order to further remove the organic solvent in the tail gas, a solid adsorbent, such as activated carbon, can be used to adsorb the residual solvent in the second tail gas, and then the solid adsorbent is filtered to obtain a gaseous mixture, wherein the gaseous mixture mainly comprises gaseous HCl and gaseous SO 2 And also includes extremely small amounts of water vapor and gaseous organic solvents.
Then separating the first gaseous mixture to obtain separated gaseous HCl and liquid SO 2 The specific separation process can refer to the prior art, and can also adopt the methods of pressurization, adsorption, filtration and pressurized rectification, wherein the first gaseous mixture is pressurized, and then the solid adsorbent is adopted again to carry out the secondary pressurization on the residual organic mattersAdsorbing with solvent, and finally, using gaseous HCl and gaseous SO 2 In the difference of volatility, the pressurized rectification technology is adopted to separate gaseous mixture, and in the pressurizing process, gaseous SO 2 Conversion to liquid SO 2 Thereby causing gaseous HCl and gaseous SO 2 Separated from each other, to obtain, after separation, gaseous HCl and liquid SO 2 。
And a phase inversion step S140: and introducing gaseous hydrogen chloride into water to obtain hydrochloric acid.
Gaseous hydrogen chloride is not easy to store, and hydrochloric acid is a relatively common chemical reagent in practical application, so that from economic consideration, the gaseous hydrogen chloride is converted into a liquid product, namely hydrochloric acid, and specifically, the gaseous hydrogen chloride is introduced into water to obtain hydrochloric acid.
In the method shown in fig. 1, it can be seen that the method effectively solves the problem of HCl and SO in water and organic matters before pressurized rectification by adsorbing impurities in chlorinated tail gas by using ionic liquid 2 The influence of the separation of the two gases solves the problems of serious corrosion and blockage caused by the adhesion of organic/inorganic solids on the pipe wall and a delivery pump generated in the process of pressure separation, and can obtain high-purity liquid SO 2 Producing a product; the ionic liquid has extremely low corrosivity, and the ionic liquid is adopted to replace concentrated sulfuric acid, so that the problems of equipment corrosion and subsequent treatment caused by concentrated sulfuric acid dehydration in the traditional technology can be effectively solved; in addition, the ionic liquid has high regenerability and simple regeneration process, and the cost of tail gas treatment is greatly reduced. The method takes the ionic liquid as the main material, is organically combined with condensation, rectification and other means, can effectively treat the chlorinated tail gas in the sucralose production process, and realizes HCl and SO 2 The effective separation of two gases to obtain high-quality hydrochloric acid and liquid SO 2 The product has simple integral treatment process and low cost and has great economic and application values.
In some embodiments of the present application, the method further comprises: a first regeneration step included in the removal step: carrying out regeneration treatment on the hydrophilic ionic liquid used in the removing step to obtain regenerated hydrophilic ionic liquid and first regenerated tail gas; and recovering the regenerated hydrophilic ionic liquid to the removal step.
In the desorption step, after the hydrophilic ionic liquid is adopted to adsorb the first tail gas and separate, the second tail gas and the hydrophilic ionic liquid with the impurities adsorbed are obtained, namely the used hydrophilic ionic liquid.
The following method can be used for the regeneration of the hydrophilic ionic liquid: sending the hydrophilic ionic liquid into an ionic liquid regeneration kettle for regeneration, collecting the regenerated hydrophilic ionic liquid from the kettle bottom of the regeneration kettle, condensing the regenerated hydrophilic ionic liquid by a condenser, filtering the regenerated hydrophilic ionic liquid by a filter, and then refluxing the regenerated hydrophilic ionic liquid for repeated use.
For the regeneration of the ionic liquid, the ionic liquid is caused to release the gaseous substances that have been adsorbed. The regeneration condition of the hydrophilic ionic liquid is not limited, and all gaseous substances adsorbed by the ionic liquid can be removed, such as stirring, heating and the like; in other embodiments of the present application, the regeneration temperature of the hydrophilic ionic liquid is 80-120 ℃ and the regeneration vacuum degree is-0.1 to-0.05 MPa for economic reasons, and the hydrophilic ionic liquid can rapidly remove adsorbed gaseous substances under the conditions.
It should be noted that, in the process of adsorbing the first tail gas, the hydrophilic ionic liquid not only adsorbs moisture and organic solvents in the tail gas, but also adsorbs a part of target products, namely HCl and SO 2 The two gases are carried out of the first tail gas along with the hydrophilic ionic liquid, SO that when the hydrophilic ionic liquid is regenerated, the generated first regenerated tail gas contains some target products of HCl and SO in addition to impurity moisture, organic solvents such as DMF and trichloroethane and the like 2 . To further increase HCl and SO 2 The first regeneration tail gas can be recycled and reprocessed SO as to separate HCl and SO in the first regeneration tail gas 2 。
In some embodiments of the present application, the method further comprises: a recovery step after the first regeneration step: absorbing the first regenerated tail gas by using oleophylic ionic liquid to remove organic components to obtain third tail gas; absorbing the third tail gas by adopting a saturated sodium chloride aqueous solution to absorb hydrogen chloride to obtain a fourth tail gas; the fourth off-gas is recycled to the first off-gas to be subjected to the removal step. Carrying out hydrogen chloride regeneration treatment on the obtained saturated sodium chloride aqueous solution adsorbed with the hydrogen chloride to obtain regenerated hydrogen chloride, and recovering the regenerated hydrogen chloride into the hydrogen chloride to be subjected to the phase conversion step; the saturated aqueous sodium chloride solution from which hydrogen chloride was released was recovered to a saturated aqueous sodium chloride solution.
In the first regenerated tail gas, the moisture content is very little, almost no, and the content of the organic component is relatively much, so when the first regenerated tail gas is recovered, lipophilic ionic liquid is selected, the adsorption effect of the lipophilic ionic liquid on the organic component is stronger than that of the hydrophilic ionic liquid, the lipophilic ionic liquid is selected to purify the first regenerated tail gas better, and after the lipophilic ionic liquid is adopted to adsorb and separate the first regenerated tail gas, the lipophilic ionic liquid with adsorbed impurities and a third tail gas are obtained.
The third tail gas mainly contains HCl and SO 2 The third tail gas can be directly separated according to the same treatment method of the second tail gas, for example, the third tail gas is adsorbed and filtered by a solid adsorbent to obtain a gaseous mixture, and the gaseous mixture is separated, including but not limited to pressurization, adsorption, filtration and pressurized rectification, to obtain gaseous hydrogen chloride and liquid sulfur dioxide; further, gaseous hydrogen chloride is introduced into water to obtain hydrochloric acid.
The separation treatment can also be carried out by a recommended method, in which the third tail gas is first adsorbed by a saturated sodium chloride aqueous solution to absorb the hydrogen chloride in the third tail gas due to SO 2 Insoluble in saturated aqueous sodium chloride solution, whereby HCl and SO 2 SO as to separate and obtain saturated sodium chloride aqueous solution adsorbing hydrogen chloride and fourth tail gas, wherein the fourth tail gas mainly contains SO 2 Due to SO 2 From a saturated sodium chloride aqueous solutionThe fourth tail gas can be recycled to the first tail gas to be subjected to the removal step, and the fourth tail gas can be recycled to remove the moisture. The obtained saturated aqueous sodium chloride solution adsorbed with hydrogen chloride is subjected to hydrogen chloride regeneration treatment, i.e. the saturated aqueous sodium chloride solution adsorbed with hydrogen chloride is made to release hydrogen chloride gas, for example, the hydrogen chloride gas can be released by heating, the purity of the regenerated hydrogen chloride is very high, and the hydrogen chloride can be directly recycled into the hydrogen chloride to be subjected to the phase conversion step. The saturated aqueous sodium chloride solution from which hydrogen chloride is released can be recycled, that is, recovered in the saturated aqueous sodium chloride solution.
In the embodiment, two types of hydrophilic and hydrophobic ionic liquids are used for treating water and organic matters in the chlorinated tail gas in a matching manner, SO that a more remarkable separation effect can be achieved, and the obtained HCl and SO 2 The purity of the product is better than that of the product which only uses hydrophilic ionic liquid.
Like hydrophilic ionic liquid, in some embodiments of this application, also can be to the recovery step in, oleophylic ionic liquid after the use carries out regeneration treatment to recycle, specific, with hydrophilic ionic liquid, send oleophylic ionic liquid into ionic liquid regeneration cauldron and regenerate, the oleophylic ionic liquid after the regeneration is taken out from the cauldron bottom of regeneration cauldron, after the condenser condensation, filtering through the filter, then just can the backward flow use repeatedly.
The regeneration of the oleophilic ionic liquid is to make the oleophilic ionic liquid release the adsorbed gaseous substances. The application does not limit the regeneration condition of the oleophylic ionic liquid, and all that is needed is to remove the adsorbed gaseous substances from the oleophylic ionic liquid, for example, the above purpose is realized by means of stirring, heating and the like; in other embodiments of the present application, the regeneration temperature of the hydrophilic ionic liquid is 80-120 ℃ and the regeneration vacuum degree is-0.1 to-0.05 MPa for economic reasons, and the ionic liquid can rapidly remove adsorbed gaseous substances under the conditions.
And a small amount of tail gas generated in the oleophylic ionic liquid regeneration process is marked as fifth tail gas, the content is low, the recovery value is not available, and the solvent can be directly recovered.
Species of hydrophilic liquid ion
In some embodiments of the present application, the kind of the hydrophilic ionic liquid is not limited, and the ionic liquid having a better affinity for water may be used; in other embodiments, the hydrophilic ionic liquid is one or more of pyridine bisulfate, methyl imidazole bisulfate, and ethyl imidazole bisulfate.
Ionic action condition of hydrophilic liquid
In some embodiments of the present application, the condition for the hydrophilic ionic liquid to adsorb the first exhaust gas, that is, the action condition of the hydrophilic ionic liquid is not limited, but the hydrophilic ionic liquid needs to be kept in an ionic liquid state, and is not converted into a solution state; because the force between the anions and the cations of the ionic liquid is coulomb acting force, the acting force between the anions and the cations can be weakened by raising the temperature, and the ionic liquid is easily converted into solution by overhigh temperature, so that in other embodiments of the application, when the hydrophilic ionic liquid is adopted to adsorb the first tail gas, the temperature can be set to be 20-50 ℃.
The kind of oleophilic liquid ion
In some embodiments of the present application, the kind of the lipophilic ionic liquid is not limited, and the ionic liquid having a better affinity for organic substances may be used; in other embodiments, the lipophilic ionic liquid is dibutyl 1-ethyl-3-methylimidazolium phosphate and/or dibutyl 1-butyl-3-methylimidazolium phosphate.
Ionic action condition of lipophilic liquid
In some embodiments of the present application, the condition for adsorbing the first regenerated exhaust gas by the lipophilic ionic liquid, that is, the action condition of the lipophilic ionic liquid is not limited, but the lipophilic ionic liquid needs to be maintained in an ionic liquid state; in other embodiments of the present application, the temperature may be set to 20-40 ℃ when the lipophilic ionic liquid is used for adsorbing the first regenerated exhaust gas.
In order to address the above method, the present application designs an exhaust gas treatment device, as shown in fig. 2, fig. 2 shows a schematic structural diagram of an exhaust gas treatment device according to an embodiment of the present application, and as can be seen from fig. 2, the exhaust gas treatment device 200 mainly includes:
a cooling tower R-1, an adsorption tower R-2, a dehydration desolventizing tower R-3, a pressurized rectification tower R-4, an adsorption tower R-5, a filter (E-1, E-2, E-3, E-4), an ionic liquid regeneration kettle V-1, an ionic liquid regeneration kettle V-2, an HCl absorption kettle V-3, an HCl regeneration kettle V-4, a filter tank T-1, a compressor T-2 and a condenser (C-1, C-2, C-3).
Wherein, the outlet of the cooling tower R-1 is connected with the inlet of the adsorption tower R-2, the gaseous substance outlet of the adsorption tower R-2 is connected with the filter tank T-1, and the filter tank T-1 is sequentially connected with the filter E-3, the compressor T-2, the filter E-4 and the pressurized rectifying tower R-4. A liquid substance outlet of the adsorption tower R-2 is connected with an inlet of the ionic liquid regeneration kettle V-1, and a liquid substance outlet of the ionic liquid regeneration kettle V-1 is connected with an ionic liquid inlet of the condenser C-1, the filter E-1 and the adsorption tower R-2. The outlet of the gaseous substance of the ionic liquid regeneration kettle V-1 is connected with the inlet of the dehydration and desolventizing tower R-3. The liquid substance outlet of the dehydration desolventizing tower R-3 is connected with the inlet of the ionic liquid regeneration kettle V-2, and the liquid substance outlet of the ionic liquid regeneration kettle V-2 is sequentially connected with the condenser C-2, the filter E-2 and the ionic liquid inlet of the adsorption tower R-2. The gaseous substance outlet of the dehydration desolventizing tower R-3 is connected with the HCl absorption kettle V-3, the HCl regeneration kettle V-4 and the adsorption tower R-5. The gaseous substance outlet of the pressurized rectifying tower R-4 is connected with the inlet of the adsorption tower R-5.
It should be noted that, the above description is only the main connection relationship of the tail gas treatment device 200, the connection relationship of each kettle or filter and the like can be adaptively adjusted according to the need, and the type of each kettle can be selected according to the respective function need, which is not limited in the present application, for example, the desolventizing kettle can be an evaporation type reaction kettle, and a vacuum pump can be provided if necessary; further, the tanks, filters, and the like in the above-described apparatus may be added or deleted as necessary.
The process of implementing the exhaust gas treatment method using the exhaust gas treatment device 200 can be briefly described as follows:
and (3) cooling and condensing the chlorinated tail gas by a cooling tower R-1 to remove most of DMF, trichloroethane and water, sending the water solution at the bottom of the cooling tower R-1 to a solvent for recovery, obtaining a first tail gas at the top of the cooling tower R-1, and continuously treating the first tail gas in a dehydration and desolventizing tower R-2.
The dehydration desolventizing tower R-2 is pre-provided with hydrophilic ionic liquid, so that residual moisture and most of solvent in the tail gas can be basically and completely removed, a second tail gas is obtained after dehydration desolventizing, and the second tail gas enters the next solid adsorbent for adsorption treatment. The hydrophilic ionic liquid absorbing water and organic solvent enters an ionic liquid regeneration kettle V-1 for dehydration, desolvation and regeneration, the regenerated hydrophilic ionic liquid is cooled by a condenser E-1 and then returns to a dehydration and desolvation tower R-2 for continuous use, and the dehydrated water, HCl and SO 2 And the mixed steam formed by the organic solvent enters a dehydration and desolventizing tower R-3 for continuous treatment.
The filter tank T-1 can be an activated carbon tank T-1, the activated carbon tank T-1 is adopted to adsorb residual solvent in the second tail gas extracted from the top of the dehydration desolventizing tower R-2, and the residual solvent enters the pressurized rectifying tower R-4 for separation treatment after being treated by a filter E-3, a compressor T-2 and a filter E-4 to obtain tower bottom high-purity liquid SO of the pressurized rectifying tower R-4 2 And (3) adsorbing the product by using an HCl gas obtained from the top of the pressurized rectifying tower R-4 to a dehydration adsorption tower R-5 to generate hydrochloric acid.
The organic matters in the third tail gas evaporated by the regeneration kettle V-1 can be basically and completely removed by the dehydration and desolventizing tower R-3, the oleophylic ionic liquid extracted from the bottom of the dehydration and desolventizing tower R-3 is regenerated by the regeneration kettle V-2 and then condensed by the condenser E-2, and then the oleophylic ionic liquid can be returned to the dehydration and desolventizing tower R-3 for continuous use; the organic matter evaporated from the regeneration kettle V-2 is subjected to solvent recovery.
Water, HCl and SO extracted from the top of R-3 of the dehydration and desolventizing tower 2 The formed mixed vapor enters an HCl absorption kettle V-3 containing saturated salt water to absorb HCl and contains SO 2 And returning the fourth tail gas of the water and the water to the dehydration and desolventizing tower R-2 for circular treatment.
Saturated salt water which is absorbed by HCl in the HCl absorption kettle V-3 enters an HCl regeneration kettle V-4, regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 enter an absorption tower R-5 to be absorbed, a hydrochloric acid product with high quality can be obtained from the bottom of the absorption tower R-5, and trace tail gas at the top of the absorption tower is treated as tail gas. The steps can be added or deleted according to the comprehensive requirements of economy and effect so as to achieve the expected effect.
Sources of chlorinated tail gases
In the following embodiments and comparative examples of the present application, when sucralose is prepared by a single-group protection method, sucrose-6-ester obtained by esterifying sucrose and a chlorinating agent are subjected to a chlorination reaction to generate a tail gas of sucralose-6-ester, which is hereinafter referred to as a chlorination tail gas.
Example 1
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 0 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 40 ℃, and the hydrophilic ionic liquid is a mixture of 50wt% of pyridine bisulfate and 50wt% of methylimidazole bisulfate. Absorbing residual organic gas by using a second tail gas extracted from the top of the dehydration and desolventizing tower R-2 through an active carbon tank T-1, treating the second tail gas through a filter E-3, a compressor T-2 and a filter E-4, and then feeding the second tail gas into a pressurized rectifying tower R-4, wherein the pressure of the pressurized rectifying tower is 2MPa, the temperature of the bottom of the tower is 0 ℃, the temperature of the top of the tower is 10 ℃, and obtaining high-purity liquid SO from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.9%; HCl gas obtained from the top of the pressurized rectifying tower R-4 enters a water adsorption tower R-5 for adsorption.
Water evaporated from the top of the regeneration kettle V-1 of the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 And the formed third tail gas enters a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein the lipophilic ionic liquid is 1-ethyl-3-methylimidazolium dibutyl phosphate, and the adsorption temperature is 25 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration and desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 85 ℃, the vacuum degree is-0.09 MPa, the oleophylic ionic liquid is cooled to 25 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration and desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of dehydration and desolventizing tower 2 And (3) recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride aqueous solution to adsorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 And (3) mixing the gas with water, recording as fifth tail gas, returning the fifth tail gas to the dehydration and desolventizing tower R-2 for continuous treatment, feeding HCl-containing saturated salt water extracted from the bottom of the absorption kettle V-3 into an HCl regeneration kettle V-4, feeding the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 into a water adsorption tower R-5 for adsorption, thus obtaining a hydrochloric acid product with high quality from the bottom of the tower, wherein the purity is 34.5%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 2
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 30 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration and desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 30 ℃, and the hydrophilic ionic liquid is a mixture of 40wt% of pyridine bisulfate and 60wt% of ethylimidazole bisulfate. The hydrophilic ionic liquid used at the bottom of the dehydration desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 100 ℃, the vacuum degree is-0.07 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 30 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the dehydration desolventizing tower R-2 is subjected to adsorption of residual organic gas by an activated carbon tank T-1, then is treated by a filter E-3, a compressor T-2 and a filter E-4, and then enters a pressurized rectifying tower R-4, the pressure of the pressurized rectifying tower is 2.5MPa, the temperature of the bottom of the tower is 5 ℃, the temperature of the top of the tower is 15 ℃, and high-purity liquid SO is obtained from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.8 percent; and the extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 enters a water adsorption tower R-5 for adsorption.
Water evaporated from the top of the regeneration kettle V-1 of the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 Form a firstThe three tail gases enter a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein the lipophilic ionic liquid is 1-butyl-3-methyl imidazole dibutyl phosphate, and the adsorption temperature is 30 ℃. After organic components are removed, lipophilic ionic liquid extracted from the bottom of the dehydration and desolventizing tower R-3 enters a lipophilic ionic liquid regeneration kettle V-2 for regeneration, the regeneration temperature is 95 ℃, the vacuum degree is-0.07 MPa, the lipophilic ionic liquid is cooled to 30 ℃ by a condenser E-2, and the lipophilic ionic liquid returns to the dehydration and desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of the dehydration and desolventizing tower 2 And (3) recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride aqueous solution to adsorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 And (3) mixing gas with water is marked as fifth tail gas, the fifth tail gas is returned to the dehydration and desolventizing tower R-2 for continuous treatment, saturated saline solution containing HCl and extracted from the bottom of the absorption kettle V-3 enters an HCl regeneration kettle V-4, the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 enter a water adsorption tower R-5 together for adsorption, a hydrochloric acid product with high quality can be obtained from the bottom of the tower, the purity is 35.8%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 3
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 10 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration and desolventizing tower R-2 which is preset with hydrophilic ionic liquid, and the adsorption temperature is set to be 40 ℃, wherein the hydrophilic ionic liquid is a mixture of 20wt% of pyridine bisulfate, 30wt% of methyl imidazole bisulfate and 50wt% of ethyl imidazole bisulfate. The hydrophilic ionic liquid used at the bottom of the dehydration and desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 120 ℃, the vacuum degree is-0.05 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 20 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration and desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the R-2 tower of the dehydration and desolventizing tower is absorbed by an activated carbon tank T-1 to remainThe organic gas is treated by a filter E-3, a compressor T-2 and a filter E-4 and then enters a pressurized rectifying tower R-4, the pressure of the pressurized rectifying tower is 1.5MPa, the temperature of the bottom of the tower is-5 ℃, the temperature of the top of the tower is 5 ℃, and high-purity liquid SO is obtained from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.7 percent; and the extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 enters a water adsorption tower R-5 for adsorption.
Water evaporated from the top of the regeneration vessel V-1 for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 And the formed third tail gas enters a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein the lipophilic ionic liquid is 1-ethyl-3-methyl imidazole dibutyl phosphate, and the adsorption temperature is 35 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 80 ℃, the vacuum degree is-0.10 MPa, the oleophylic ionic liquid is cooled to 25 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of dehydration and desolventizing tower 2 And recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride water solution to absorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 And recording the mixed gas of water as fifth tail gas, returning the fifth tail gas to the dehydration and desolventizing tower R-2 for continuous treatment, feeding saturated salt water containing HCl, which is extracted from the bottom of the absorption kettle V-3, into the HCl regeneration kettle V-4, feeding the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 into the water adsorption tower R-5 for adsorption, thus obtaining a hydrochloric acid product with high quality from the bottom of the tower, wherein the purity is 35.6%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 4
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 0 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration and desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 40 ℃, wherein the hydrophilic ionic liquid is 50wt% of pyridineA mixture of bisulfate salt and 50wt% of methyl imidazole bisulfate salt. The hydrophilic ionic liquid used at the bottom of the dehydration and desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 80 ℃, the vacuum degree is-0.10 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 40 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration and desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the dehydration desolventizing tower R-2 is subjected to adsorption of residual organic gas by an activated carbon tank T-1, then is treated by a filter E-3, a compressor T-2 and a filter E-4, and then enters a pressurized rectifying tower R-4, the pressure of the pressurized rectifying tower is 2MPa, the temperature of the bottom of the tower is 0 ℃, the temperature of the top of the tower is 10 ℃, and high-purity liquid SO is obtained from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.9%; and (3) leading extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 to enter a water adsorption tower R-5 for adsorption treatment.
Water evaporated from the top of the regeneration vessel V-1 for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 And the formed third tail gas enters a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein the lipophilic ionic liquid is 1-ethyl-3-methyl imidazole dibutyl phosphate, and the adsorption temperature is 20 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 90 ℃, the vacuum degree is-0.08 MPa, the oleophylic ionic liquid is cooled to 20 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of dehydration and desolventizing tower 2 And (3) recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride aqueous solution to adsorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 And (3) mixing gas with water is marked as fifth tail gas, the fifth tail gas is returned to the dehydration and desolventizing tower R-2 for continuous treatment, saturated saline solution containing HCl and extracted from the bottom of the absorption kettle V-3 enters an HCl regeneration kettle V-4, the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 enter a water adsorption tower R-5 together for adsorption, a hydrochloric acid product with high quality can be obtained from the bottom of the tower, the purity is 35.1%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is supplemented with part of pure waterReturning to the HCl absorption kettle V-3 for continuous use.
Example 5
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 30 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 30 ℃, and the hydrophilic ionic liquid is a mixture of 40wt% of pyridine bisulfate and 60wt% of ethylimidazole bisulfate. The hydrophilic ionic liquid used at the bottom of the dehydration desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 100 ℃, the vacuum degree is-0.07 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 30 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the dehydration desolventizing tower R-2 is subjected to adsorption of residual organic gas by an activated carbon tank T-1, then is treated by a filter E-3, a compressor T-2 and a filter E-4, and then enters a pressurized rectifying tower R-4, the pressure of the pressurized rectifying tower is 2.5MPa, the temperature of the bottom of the tower is 5 ℃, the temperature of the top of the tower is 15 ℃, and high-purity liquid SO is obtained from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.8 percent; and (3) leading extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 to enter a water adsorption tower R-5 for adsorption treatment.
Water evaporated from the top of the regeneration vessel V-1 for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 And the formed third tail gas enters a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein the lipophilic ionic liquid is 1-butyl-3-methyl imidazole dibutyl phosphate, and the adsorption temperature is 40 ℃. After organic components are removed, lipophilic ionic liquid extracted from the bottom of the dehydration and desolventizing tower R-3 enters a lipophilic ionic liquid regeneration kettle V-2 for regeneration, the regeneration temperature is 80 ℃, the vacuum degree is-0.10 MPa, the lipophilic ionic liquid is cooled to 40 ℃ by a condenser E-2, and the lipophilic ionic liquid returns to the dehydration and desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of the dehydration and desolventizing tower 2 And (3) recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride aqueous solution to adsorb HCl gas at normal temperature. Extracted from the top of the kettle containsWith SO 2 And (3) mixing gas with water is marked as fifth tail gas, the fifth tail gas is returned to the dehydration and desolventizing tower R-2 for continuous treatment, saturated saline solution containing HCl and extracted from the bottom of the absorption kettle V-3 enters an HCl regeneration kettle V-4, the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 enter a water adsorption tower R-5 together for adsorption, a hydrochloric acid product with high quality can be obtained from the bottom of the tower, the purity is 37.0%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 6
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 10 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration and desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 20 ℃, and the hydrophilic ionic liquid is a mixture of 20wt% of pyridine bisulfate, 30wt% of methyl imidazole bisulfate and 50wt% of ethyl imidazole bisulfate. The hydrophilic ionic liquid used at the bottom of the dehydration desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 120 ℃, the vacuum degree is-0.05 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 20 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the dehydration and desolventizing tower R-2 is subjected to adsorption of residual organic gas by an active carbon tank T-1, then is treated by a filter E-3, a compressor T-2 and a filter E-4, and then enters a pressurized rectifying tower R-4, the pressure of the pressurized rectifying tower is 1.5MPa, the temperature of the bottom of the tower is-5 ℃, the temperature of the top of the tower is 5 ℃, and high-purity liquid SO is obtained from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.9%; and (3) leading extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 to enter a water adsorption tower R-5 for adsorption treatment.
Water evaporated from the top of the V-1 regeneration vessel for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 The third tail gas formed enters a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein the lipophilic ionic liquid is 50wt%Dibutyl ester and 50wt% dibutyl 1-butyl-3-methylimidazolium phosphate, adsorption temperature 30 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 110 ℃, the vacuum degree is-0.07 MPa, the oleophylic ionic liquid is cooled to 30 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of dehydration and desolventizing tower 2 And (3) recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride aqueous solution to adsorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 And (3) mixing the gas with water, recording as fifth tail gas, returning the fifth tail gas to the dehydration and desolventizing tower R-2 for continuous treatment, feeding HCl-containing saturated salt water extracted from the bottom of the absorption kettle V-3 into an HCl regeneration kettle V-4, feeding the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 into a water adsorption tower R-5 for adsorption, thus obtaining a hydrochloric acid product with high quality from the bottom of the tower, wherein the purity is 34.9%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 7
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 20 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration and desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 50 ℃, and the hydrophilic ionic liquid is a mixture of 75wt% of methylimidazole bisulfate and 25wt% of ethylimidazole bisulfate. The hydrophilic ionic liquid used at the bottom of the dehydration desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 110 ℃, the vacuum degree is-0.06 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 50 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the dehydration and desolventizing tower R-2 is treated by an activated carbon tank T-1 to adsorb residual organic gas, a filter E-3, a compressor T-2 and a filter E-4 and then addedPressing a rectifying tower R-4, wherein the pressure of the pressing rectifying tower is 1.0MPa, the temperature of the bottom of the tower is-10 ℃, the temperature of the top of the tower is 0 ℃, and high-purity liquid SO is obtained from the bottom of the pressing rectifying tower R-4 2 The purity is 99.8 percent; and (3) leading extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 to enter a water adsorption tower R-5 for adsorption treatment.
Water evaporated from the top of the regeneration vessel V-1 for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 The third tail gas formed enters a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein, the lipophilic ionic liquid is a mixture of 85wt percent of 1-ethyl-3-methyl imidazole dibutyl phosphate and 15wt percent of 1-butyl-3-methyl imidazole dibutyl phosphate, and the adsorption temperature is 35 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 110 ℃, the vacuum degree is-0.07 MPa, the oleophylic ionic liquid is cooled to 30 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of dehydration and desolventizing tower 2 And (3) recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride aqueous solution to adsorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 And (3) mixing the gas with water, recording as fifth tail gas, returning the fifth tail gas to the dehydration and desolventizing tower R-2 for continuous treatment, feeding HCl-containing saturated salt water extracted from the bottom of the absorption kettle V-3 into an HCl regeneration kettle V-4, feeding the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 into a water adsorption tower R-5 for adsorption, thus obtaining a hydrochloric acid product with high quality from the bottom of the tower, wherein the purity is 36.1%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 8
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 15 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 25 ℃, wherein the hydrophilic ionic liquid is 15wt% of methylimidazole sulfuric acidA mixture of hydrogen salt and 85wt% of ethylimidazole hydrogen sulfate. The hydrophilic ionic liquid used at the bottom of the dehydration desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 100 ℃, the vacuum degree is-0.07 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 25 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the dehydration desolventizing tower R-2 is subjected to adsorption of residual organic gas by an activated carbon tank T-1, then is treated by a filter E-3, a compressor T-2 and a filter E-4, and then enters a pressurized rectifying tower R-4, wherein the pressure of the pressurized rectifying tower is 3.0MPa, the temperature of the bottom of the tower is 10 ℃, the temperature of the top of the tower is 20 ℃, and high-purity liquid SO is obtained from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.7%; and the extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 enters a water adsorption tower R-5 for adsorption treatment.
Water evaporated from the top of the regeneration vessel V-1 for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 The third tail gas thus formed enters a dehydration and desolventizing column R-3 which is provided with a lipophilic ionic liquid beforehand, wherein the lipophilic ionic liquid is a mixture of 25wt% of dibutyl 1-ethyl-3-methylimidazolium phosphate and 75wt% of dibutyl 1-butyl-3-methylimidazolium phosphate, and the adsorption temperature is 25 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 95 ℃, the vacuum degree is-0.08 MPa, the oleophylic ionic liquid is cooled to 25 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of dehydration and desolventizing tower 2 And (3) recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride aqueous solution to adsorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 The mixed gas of the HCl and the water is marked as a fifth tail gas, the fifth tail gas returns to the dehydration and desolventizing tower R-2 for continuous treatment, the saturated saline solution containing HCl and extracted from the bottom of the absorption kettle V-3 enters the HCl regeneration kettle V-4, the regenerated HCl vapor and the HCl gas extracted from the top of the pressurized rectifying tower R-4 enter the water absorption tower R-5 together for absorption, the hydrochloric acid product with higher quality can be obtained from the bottom of the tower, the purity is 35.5 percent, and trace tail gas at the top of the tower is taken as the tail gasAnd (6) processing. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 9
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 5 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 35 ℃, and the hydrophilic ionic liquid is a mixture of 15wt% of pyridine bisulfate and 85wt% of ethylimidazole bisulfate. The hydrophilic ionic liquid used at the bottom of the dehydration and desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 105 ℃, the vacuum degree is-0.07 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 35 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration and desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the dehydration desolventizing tower R-2 is subjected to adsorption of residual organic gas by an activated carbon tank T-1, then is treated by a filter E-3, a compressor T-2 and a filter E-4, and then enters a pressurized rectifying tower R-4, the pressure of the pressurized rectifying tower is 2.5MPa, the temperature of the bottom of the tower is 5 ℃, the temperature of the top of the tower is 15 ℃, and high-purity liquid SO is obtained from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.9%; and (3) leading extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 to enter a water adsorption tower R-5 for adsorption treatment.
Water evaporated from the top of the regeneration vessel V-1 for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 And the formed third tail gas enters a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein the lipophilic ionic liquid is 1-ethyl-3-methylimidazolium dibutyl phosphate, and the adsorption temperature is 35 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration and desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 85 ℃, the vacuum degree is-0.09 MPa, the oleophylic ionic liquid is cooled to 35 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration and desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of dehydration and desolventizing tower 2 The mixed gas is marked as fourth tail gas, and the fourth tail gas enters the gas containing saturated sodium chloride aqueous solutionHCl gas is absorbed by the HCl absorption kettle V-3 and is absorbed at normal temperature. SO-containing gas extracted from the top of the kettle 2 And (3) mixing the gas with water, recording as fifth tail gas, returning the fifth tail gas to the dehydration and desolventizing tower R-2 for continuous treatment, feeding HCl-containing saturated salt water extracted from the bottom of the absorption kettle V-3 into an HCl regeneration kettle V-4, feeding the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 into a water adsorption tower R-5 for adsorption, thus obtaining a hydrochloric acid product with high quality from the bottom of the tower, wherein the purity is 36.5%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 10
The chlorinated tail gas is cooled and condensed by a cooling tower R-1 to 25 ℃, after condensation, the bottom water solution of the cooling tower R-1 is sent to a solvent for recovery, and the top tail gas of the cooling tower R-1, namely the first tail gas enters a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 45 ℃, and the hydrophilic ionic liquid is a mixture of 35wt% of pyridine acid hydrogen salt and 65wt% of methyl imidazole hydrogen sulfate. The hydrophilic ionic liquid used at the bottom of the dehydration desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 115 ℃, the vacuum degree is-0.06 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 45 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration desolventizing tower R-2 for continuous use. Absorbing residual organic gas by using a second tail gas extracted from the top of the dehydration and desolventizing tower R-2 through an active carbon tank T-1, treating the second tail gas through a filter E-3, a compressor T-2 and a filter E-4, and then feeding the second tail gas into a pressurized rectifying tower R-4, wherein the pressure of the pressurized rectifying tower is 1.5MPa, the temperature of the bottom of the tower is-5 ℃, the temperature of the top of the tower is 5 ℃, and obtaining high-purity liquid SO from the bottom of the pressurized rectifying tower R-4 2 The purity is 99.7%; and (3) leading extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 to enter a water adsorption tower R-5 for adsorption treatment.
Water evaporated from the top of the regeneration vessel V-1 for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 The third tail gas enters a dehydration and desolventizing tower R-3 which is preset with oleophylic ionic liquid, wherein the oleophylic ionic liquid is 1-butylDibutyl 3-methylimidazolyl phosphate at an adsorption temperature of 20 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 115 ℃, the vacuum degree is-0.06 MPa, the oleophylic ionic liquid is cooled to 20 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of dehydration and desolventizing tower 2 And recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride water solution to absorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 And (3) mixing the gas with water, recording as fifth tail gas, returning the fifth tail gas to the dehydration and desolventizing tower R-2 for continuous treatment, feeding HCl-containing saturated salt water extracted from the bottom of the absorption kettle V-3 into an HCl regeneration kettle V-4, feeding the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 into a water adsorption tower R-5 for adsorption, thus obtaining a hydrochloric acid product with high quality from the bottom of the tower, wherein the purity is 35.5%, and trace tail gas at the top of the tower is treated as the tail gas. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Example 11
And (3) cooling and condensing the chlorinated tail gas to 35 ℃ through a cooling tower R-1, sending the water solution at the bottom of the cooling tower R-1 to a solvent for recycling after condensation, and sending the tail gas at the top of the cooling tower R-1, namely the first tail gas into a dehydration and desolventizing tower R-2 for continuous treatment. The first tail gas enters a dehydration desolventizing tower R-2 which is preset with hydrophilic ionic liquid, the adsorption temperature is set to be 35 ℃, and the hydrophilic ionic liquid is a mixture of 75wt% of pyridine acid hydrogen salt and 25wt% of ethylimidazole hydrogen sulfate. The hydrophilic ionic liquid used at the bottom of the dehydration and desolventizing tower R-2 enters an ionic liquid regeneration kettle V-1 for regeneration treatment, the regeneration temperature is 85 ℃, the vacuum degree is-0.09 MPa, the regenerated hydrophilic ionic liquid is extracted from the kettle bottom of the regeneration kettle V-1, cooled to 35 ℃ by a condenser E-1 and filtered by a filter E-1, and then the hydrophilic ionic liquid returns to the dehydration and desolventizing tower R-2 for continuous use. The second tail gas extracted from the top of the dehydration and desolventizing tower R-2 is treated by an active carbon tank T-1 to adsorb residual organic gas, then treated by a filter E-3, a compressor T-2 and a filter E-4 and enters a pressurized rectifying tower R-4, and the pressure of the pressurized rectifying tower is 1.0MPa, the temperature of the bottom of the tower is-10 ℃, the temperature of the top of the tower is 0 ℃, and high-purity liquid SO is obtained from the bottom of the pressure rectifying tower R-4 2 The purity is 99.9%; and (3) leading extracted HCl gas obtained from the top of the pressurized rectifying tower R-4 to enter a water adsorption tower R-5 for adsorption treatment.
Water evaporated from the top of the regeneration vessel V-1 for the hydrophilic ionic liquid, organic solvent and a small amount of HCl and SO 2 And the formed third tail gas enters a dehydration and desolventizing tower R-3 which is preset with lipophilic ionic liquid, wherein the lipophilic ionic liquid is 1-ethyl-3-methylimidazolium dibutyl phosphate, and the adsorption temperature is 25 ℃. After organic components are removed, the oleophylic ionic liquid extracted from the bottom of the dehydration desolventizing tower R-3 enters a regeneration kettle V-2 of the oleophylic ionic liquid for regeneration, the regeneration temperature is 105 ℃, the vacuum degree is-0.07 MPa, the oleophylic ionic liquid is cooled to 25 ℃ by a condenser E-2, and then the oleophylic ionic liquid returns to the dehydration desolventizing tower R-3 for continuous use. Water, HCl and SO extracted from the top of R-3 of the dehydration and desolventizing tower 2 And recording the formed mixed gas as fourth tail gas, and allowing the fourth tail gas to enter an HCl absorption kettle V-3 containing a saturated sodium chloride water solution to absorb HCl gas at normal temperature. SO-containing gas extracted from the top of the kettle 2 And (3) recording the mixed gas of the water and the water as fifth tail gas, returning the fifth tail gas to the dehydration and desolventizing tower R-2 for continuous treatment, feeding saturated salt water containing HCl, which is extracted from the bottom of the absorption kettle V-3, into the HCl regeneration kettle V-4, feeding the regenerated HCl vapor and HCl gas extracted from the top of the pressurized rectifying tower R-4 into the water adsorption tower R-5 for adsorption, thus obtaining a hydrochloric acid product with high quality from the bottom of the tower, wherein the purity is 36.5%, and removing trace tail gas from the top of the tower for tail gas treatment. The saturated salt water generated in the regeneration kettle V-4 is added with part of pure water and then returns to the HCl absorption kettle V-3 for continuous use.
Comparative example 1
Condensing the chlorinated tail gas in a condensing tower at the condensing temperature of 20 ℃, removing most of organic solvent, dehydrating the chlorinated tail gas by concentrated sulfuric acid until the water content is lower than 0.01 percent, adsorbing the gas by activated carbon, compressing the gas by a compressor, and separating the gas in a pressurized rectifying tower at the pressure of 1.0MPa, the temperature of the bottom of the tower of-10 ℃ and the temperature of the top of the tower of 0 ℃, and obtaining liquid SO from the bottom of the pressurized rectifying tower R-4 2 The purity is 98.5 percent, wherein the content of organic matters is 1.3 percent; the HCl gas at the tower top enters a water adsorption tower for adsorption, and is obtained at the tower bottomThe purity of the hydrochloric acid product is 35.1 percent, and trace gas at the top of the tower is used for tail gas treatment.
To sum up, the ionic liquid is utilized to adsorb impurities in the chlorinated tail gas, and before pressurization and rectification, the problems of water and organic matters on HCl and SO are effectively solved 2 The influence of the separation of the two gases solves the problems of serious corrosion and blockage caused by the adhesion of organic/inorganic solids on the pipe wall and a delivery pump generated in the process of pressure separation, and can obtain high-purity liquid SO 2 Producing a product; the ionic liquid has extremely low corrosivity, and the ionic liquid is adopted to replace concentrated sulfuric acid, so that the problems of equipment corrosion and subsequent treatment caused by concentrated sulfuric acid dehydration in the traditional technology can be effectively solved; in addition, the ionic liquid has high regenerability and simple regeneration process, and the cost of tail gas treatment is greatly reduced. The method takes the ionic liquid as the main material, is organically combined with condensation, rectification and other means, can effectively treat the chlorinated tail gas in the sucralose production process, and realizes HCl and SO 2 The effective separation of two gases to obtain high-quality hydrochloric acid and liquid SO 2 The product has simple integral treatment process and low cost and has great economic and application values.
In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
While the foregoing is directed to embodiments of the present application, other modifications and variations of the present application may be devised by those skilled in the art in light of the above teachings. It should be understood by those skilled in the art that the foregoing detailed description is for the purpose of better explaining the present application, and the scope of protection of the present application shall be subject to the scope of protection of the claims.
Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.

Claims (6)

1. A tail gas treatment method, wherein the tail gas is generated in the process of producing sucralose-6-ester by chlorination reaction of sucrose-6-ester, the method comprises the following steps:
a condensation step: cooling and condensing the tail gas to remove part of the organic solvent and part of water to obtain a first solution and a first tail gas;
a removing step: absorbing and separating the first tail gas by using hydrophilic ionic liquid to remove most of water and part of organic solvent in the first tail gas to obtain second tail gas, and performing regeneration treatment on the hydrophilic ionic liquid used in the removing step to obtain regenerated hydrophilic ionic liquid and first regenerated tail gas; recovering the regenerated hydrophilic ionic liquid for use in the removal step, and adsorbing the first regenerated tail gas by using lipophilic ionic liquid to remove organic components to obtain a third tail gas; absorbing the third tail gas by adopting a saturated sodium chloride aqueous solution to absorb hydrogen chloride to obtain a fourth tail gas;
recovering the fourth tail gas into the first tail gas to be subjected to the removal step; carrying out hydrogen chloride regeneration treatment on the obtained saturated sodium chloride aqueous solution adsorbed with the hydrogen chloride to obtain regenerated hydrogen chloride, and recovering the regenerated hydrogen chloride into the hydrogen chloride to be subjected to the phase conversion step; recovering a saturated sodium chloride aqueous solution which releases hydrogen chloride into the saturated sodium chloride aqueous solution, wherein the lipophilic ionic liquid is 1-ethyl-3-methylimidazolium dibutyl phosphate and/or 1-butyl-3-methylimidazolium dibutyl phosphate; the adsorption of the first regenerated tail gas by using the oleophilic ionic liquid comprises the following steps: absorbing the first regenerated tail gas by using lipophilic ionic liquid at the temperature of 20-40 ℃; the hydrophilic ionic liquid is one or more of pyridine bisulfate, methyl imidazole bisulfate and ethyl imidazole bisulfate;
a separation step: adsorbing and filtering the second tail gas by using a solid adsorbent to obtain a gaseous mixture, and separating the gaseous mixture to obtain gaseous hydrogen chloride and liquid sulfur dioxide; and
phase inversion step: and (3) introducing the gaseous hydrogen chloride into water to obtain hydrochloric acid.
2. The method according to claim 1, wherein the regeneration temperature of the hydrophilic ionic liquid is 80 to 120 ℃, and the regeneration vacuum degree is-0.1 to-0.05 MPa.
3. The method of claim 1, further comprising:
a second regeneration step after the recovery step: carrying out regeneration treatment on the oleophylic ionic liquid used in the recovery step to obtain regenerated oleophylic ionic liquid and fifth tail gas;
recovering the regenerated oleophilic ionic liquid for use in the recovering step;
and carrying out solvent recovery treatment on the fifth tail gas.
4. The method according to claim 3, wherein the regeneration temperature of the lipophilic ionic liquid is 80 to 120 ℃, and the regeneration vacuum degree is-0.1 to-0.05 MPa.
5. The method according to claim 1, wherein in the condensing step, the temperature of the reduced-temperature condensation is set to be 0 to 30 ℃.
6. The method of claim 1, wherein the adsorbing the first exhaust gas with the hydrophilic ionic liquid comprises:
and adsorbing the first tail gas by using a hydrophilic ionic liquid at the temperature of 20-50 ℃.
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