阅读说明：本技术 牛磺酸的结晶方法 (Method for crystallizing taurine ) 是由 彭俊华 何孝祥 姚祥华 陈志荣 潘映霞 黄永波 季梓军 张丽梅 于 2019-12-03 设计创作，主要内容包括：本发明涉及一种牛磺酸的结晶方法,包括：(1)提供羟乙基磺酸碱金属盐,将所述羟乙基磺酸碱金属盐进行氨解,得到氨解液；(2)将所述氨解液进行酸化,得到pH≤8的酸化液；(3)采用碱性树脂对所述酸化液进行处理,得到精制液；(4)将所述精制液进行结晶,得到牛磺酸。本发明利用酸化液中牛磺酸、二牛磺酸钠、三牛磺酸钠、羟乙基磺酸钠、无机盐等杂质的等电点的规律和在pH≤8时各物质在酸化液中的存在状态,在传统酸化步骤与结晶步骤之间,增加碱性树脂处理的步骤,通过碱性树脂吸附二牛磺酸根、三牛磺酸根、羟乙基磺酸根、硫酸根等阴离子,有效降低了牛磺酸结晶时溶液的粘稠度,从而提高牛磺酸的结晶产率。(The invention relates to a crystallization method of taurine, which comprises the following steps: (1) providing an alkali metal isethionate, and carrying out ammonolysis on the alkali metal isethionate to obtain an ammonolysis solution; (2) acidifying the ammonolysis solution to obtain an acidified solution with the pH value of less than or equal to 8; (3) treating the acidizing fluid by using alkaline resin to obtain refined fluid; (4) crystallizing the refined liquid to obtain taurine. According to the invention, by utilizing the rule of isoelectric points of impurities such as taurine, sodium ditallow, sodium trithionate, sodium isethionate and inorganic salt in the acidizing fluid and the existing states of all substances in the acidizing fluid when the pH value is less than or equal to 8, a step of treating with alkaline resin is added between the traditional acidizing step and the crystallization step, and anions such as di-taurinate, tri-taurinate, isethionate and sulfate radical are adsorbed by the alkaline resin, so that the viscosity of the solution during crystallization of taurine is effectively reduced, and the crystallization yield of taurine is improved.)

1. A method of crystallizing taurine, comprising:

(1) providing an alkali metal isethionate, and carrying out ammonolysis on the alkali metal isethionate to obtain an ammonolysis solution;

(2) acidifying the ammonolysis solution to obtain an acidified solution with the pH value of less than or equal to 8;

(3) treating the acidizing fluid by using alkaline resin to obtain refined fluid; and

(4) crystallizing the refined liquid to obtain taurine.

2. The method for crystallizing taurine according to claim 1, wherein the step (3) comprises the following steps: the acidified solution is passed through a device containing the basic resin at a flow rate of 6-15 mL/min.

3. The method for crystallizing taurine according to claim 1, wherein the basic resin comprises a weakly basic resin in step (3).

4. A crystallization method of taurine according to claim 3, wherein in step (3), the weakly basic resin contains a weakly basic group which is a primary amine group, a secondary amine group, or a tertiary amine group.

5. The method for crystallizing taurine according to claim 1, wherein the step (3) further comprises washing the basic resin with an alkaline solution after the treatment of the acidified solution with the basic resin to obtain an eluate.

6. The method for crystallizing taurine according to claim 5, wherein the eluent is recycled to the step (1) for ammonolysis.

7. The method for crystallizing taurine according to claim 6, further comprising a step of desalting the eluate before the eluate is recycled to step (1).

8. A method for crystallizing taurine according to any one of claims 1 to 7, wherein in step (3), the acidified liquid is treated with the basic resin and then treated with a first acidic resin to obtain the purified liquid.

9. The method for crystallizing taurine according to claim 8, wherein the step (3) further comprises washing the first acidic resin with an acidic solution after the treatment with the first acidic resin.

10. The method for crystallizing taurine according to any one of claims 1 to 6, wherein in the step (2), the ammonolysis solution is acidified with a second acidic resin.

11. The method for crystallizing taurine according to claim 10, wherein the step (2) further comprises washing the second acidic resin with an acidic solution after the second acidic resin acidifies the ammonolysis solution.

Technical Field

The invention relates to the technical field of taurine preparation, in particular to a crystallization method of taurine.

Background

Taurine (2-aminoethanesulfonic acid), also known as taurocholic acid and taurocholic acid, is white crystal or powder, odorless, nontoxic, and slightly sour. It is a non-protein amino acid, one of the essential amino acids, and has unique pharmacological, nutritive and health-care functions. Taurine can be widely used in the fields of medicine, food additive, fluorescent whitening agent, organic synthesis and the like, and can also be used as biochemical reagent, wetting agent, buffering agent and the like. Taurine is commonly used in medicine and food additives in developed western countries.

The preparation method of taurine mainly comprises a biological extraction method, a fermentation method and a chemical synthesis method, wherein the chemical synthesis method is most rapidly researched. The current general industrial production method of taurine is an ethylene oxide method: ethylene oxide is used as a raw material, firstly, the ethylene oxide and sodium bisulfite are subjected to ring-opening addition, then, the ethylene oxide and sodium bisulfite react with ammonia under the conditions of heating and pressurization to synthesize sodium taurate, and taurine is obtained by acidification.

Patent DD219023 mentions the composition of the ammonolysis product of sodium isethionate, wherein ammonia and sodium isethionate react for 5-45 minutes at 200-290 ℃ in the presence of an alkali metal or alkali metal hydroxide as a catalyst to obtain the ammonolysis product containing 71% sodium taurate, 29% sodium ditallow and sodium trithionate, and the yield is only 64% at most. The process used in WO01/77071 is to heat an aqueous solution of sodium taurate to 210 ℃ in the presence of a reaction medium to give a mixture of sodium taurate and sodium ditallow. It is known that during the process of preparing taurine by an ethylene oxide method, byproducts of di-taurate and tri-taurate are easily generated. In order to improve the ammonolysis yield, some researches are carried out in the prior art, such as documents [ Liu Fu Ming, Shandong chemical industry [ J ], 2015,44:27-28,30], patent CN105732440 and CN108314633, all or most of mother liquor obtained by separating ammonolysis reaction liquid after acid neutralization is recycled to ammonolysis, and the more mother liquor is added, the higher the ammonolysis reaction yield is. The above documents all mention that the mother liquor is circulated to ammonolysis for continuous reaction, the yield is greatly improved, but the mother liquor contains a plurality of complex components such as sodium sulfate, ethylene glycol, polyethylene glycol, trace metal elements and the like besides by-products of ditetranesulfonate and trinetranesulfonate, when the untreated mother liquor is circulated to the system, a large amount of impurities in the system are gathered along with the increase of the circulation times, which is not beneficial to the reaction, and if the untreated mother liquor is directly discharged, the untreated mother liquor is high-concentration pollutants, which has great influence on the environment.

In addition, for the acidification process of sodium taurate, reagents such as sulfuric acid and hydrochloric acid are commonly used in the prior art for treatment, for example, in patents US9061976, CN101486669 and CN101508657, sulfuric acid or sulfurous acid is used for acidification. The acidification by sulfuric acid is easy to generate a large amount of inorganic salts such as sodium sulfate and the like, which causes the problems of difficult separation, equipment blockage, high production cost and the like.

Therefore, when taurine is produced by a conventional ethylene oxide method, byproducts such as alkali ditaurinate and alkali tritaurinate are inevitably produced during the ammonolysis process, and the content of the alkali taurate does not exceed 80%. In addition, only the alkali taurate can be directly converted into taurine in the subsequent acidification process, and the alkali ditaurinate and the alkali tritaurinate can not be directly converted into taurine and become impurities, so that the crystallization yield of the taurine is low.

Disclosure of Invention

In view of the above, it is necessary to provide a crystallization method of taurine; the method can selectively remove impurities, reduce the viscosity of the solution during crystallization of the taurine and improve the crystallization yield of the taurine.

A method of crystallizing taurine comprising:

(1) providing an alkali metal isethionate, and carrying out ammonolysis on the alkali metal isethionate to obtain an ammonolysis solution;

(2) acidifying the ammonolysis solution to obtain an acidified solution with the pH value of less than or equal to 8;

(3) treating the acidizing fluid by using alkaline resin to obtain refined fluid;

(4) crystallizing the refined liquid to obtain taurine.

Further, the specific process of the step (3) is as follows: the acidified solution is passed through a device containing the basic resin at a flow rate of 6-15 mL/min.

Further, in the step (3), the basic resin includes a weakly basic resin.

Further, in the step (3), the weakly basic resin contains a weakly basic group, and the group is a primary amine group, a secondary amine group or a tertiary amine group.

Further, in the step (3), after the treatment of the acidizing fluid by the alkaline resin, the alkaline resin is washed by an alkaline solution to obtain an eluent.

Further, the eluent is recycled to the step (1) for ammonolysis.

Further, before the eluent is recycled to the step (1), the method also comprises a step of desalting the eluent.

Further, in the step (3), after the acidified liquid is treated with the basic resin, the acidified liquid is further treated with a first acidic resin to obtain the refined liquid.

Further, in the step (3), after the first acidic resin is treated, the method further comprises washing the first acidic resin with an acid solution.

Further, in the step (2), the ammonolysis solution is acidified by using a second acidic resin.

Further, in the step (2), after the second acidic resin acidifies the ammonolysis solution, the method further includes washing the second acidic resin with an acid solution.

The crystallization method mainly comprises the following steps: by utilizing the rule of isoelectric points of impurities such as taurine, sodium ditallow, sodium trithionate, sodium isethionate and inorganic salt in the acidizing fluid and the existing state of each substance in the acidizing fluid when the pH is less than or equal to 8, a step of treating alkaline resin is added between the traditional acidizing step and the crystallization step, and anions such as ditallow, tritallow, isethionate and sulfate radicals are adsorbed by the alkaline resin, so that the viscosity of the solution during crystallization of taurine is effectively reduced, the crystallization yield of taurine is improved, and the problems that the inorganic salt is difficult to separate and the equipment is easy to block are solved.

Drawings

FIG. 1 is a schematic view of a production process according to a first embodiment of the present invention;

FIG. 2 is a dissociation curve of taurine with pH of the solution;

FIG. 3 is a schematic view of a production process according to a second embodiment of the present invention;

fig. 4 is a schematic view of a production method according to a third embodiment of the present invention.

Detailed Description

The method for crystallizing taurine according to the present invention will be further described with reference to the accompanying drawings.

In the preparation process of taurine, after long and intensive research, the applicant finds that one of the reasons for the low crystallization yield of taurine is as follows: substances such as ditaurine alkali metal salt, tritaurine alkali metal salt and the like contained in the acidified solution after acidification can cause the solution to become viscous in the process of crystallizing taurine, thus being not beneficial to the crystallization and separation of taurine.

Therefore, the method for crystallizing taurine provided by the invention can effectively separate substances such as the ditaurine alkali metal salt, the tritaurine alkali metal salt and the like in the acidized fluid so as to reduce the viscosity of the solution in the process of crystallizing the taurine and improve the crystallization yield of the taurine.

The first implementation mode comprises the following steps:

as shown in fig. 1, the method for crystallizing taurine according to the present embodiment includes:

(1) providing an alkali metal isethionate, and carrying out ammonolysis on the alkali metal isethionate to obtain an ammonolysis solution;

(2) acidifying the ammonolysis solution to obtain an acidified solution with the pH value of less than or equal to 8;

(3) treating the acidizing fluid by using alkaline resin to obtain refined fluid;

(4) crystallizing the refined liquid to obtain taurine.

In the step (1), the isethionic acid alkali metal salt includes at least one of sodium isethionate, potassium isethionate and lithium isethionate, preferably sodium isethionate.

The reaction conditions of the ammonolysis are as follows: the temperature range is 200-290 ℃, and the pressure range is 10-20 MPa.

And after ammonolysis, deamination is also included to obtain the ammonolysis solution. It is understood that the ammonolysis solution includes, in addition to alkali taurate, ethylene glycol, alkali isethionate, alkali ditaurinate, and alkali tritaurinate.

In the step (2), the ammonolysis solution is acidified by using acidic solutions such as sulfuric acid, sulfurous acid, hydrochloric acid and the like, and the obtained acidified solution also comprises byproducts of aminolysis of ethylene oxide such as ethylene glycol, unreacted alkali metal isethionate, alkali metal ditaurinate and alkali metal tritaurinate, and inorganic salts such as sulfate, sulfite and hydrochloride generated in the acidification process, besides taurine.

As shown in fig. 2, taurine has a pH of about 5 and an isoelectric point of 5.12, and in these components, anions of sulfate, sulfite, hydrochloride, di-taurinate, tri-taurinate and isethionate are all more acidic than taurinate, so the isoelectric points of these substances are all less than 5.12, e.g., the isoelectric point of di-taurinate is about 2.

Meanwhile, when the pH of the acidified liquid is 8 or less, taurine exists mainly in a cationic and zwitterionic state, and ditaurine alkali metal salt, tritaurine alkali metal salt, isethionic acid alkali metal salt and inorganic salt all exist in a cationic and anionic state.

Therefore, in the step (3), the acidified solution having a pH of 8 or less is treated with an alkaline resin by utilizing the isoelectric point rule of these substances and the existence state of the substances. Specifically, in the treatment process, the basic resin only adsorbs anions, i.e., taurine can exist in molecular form and directly pass through the basic resin, while anions of other substances such as di-taurinate, tri-taurinate, isethionate, inorganic salts such as sulfate, hydrochloride, etc. are selectively adsorbed on the basic resin.

In the selective adsorption process of the basic resin, if the basic resin is too basic, taurine may be adsorbed, and to avoid this phenomenon, the basic resin is preferably a weakly basic resin, and more preferably, the weakly basic resin contains a weakly basic group, which is a primary amine group, a secondary amine group, or a tertiary amine group.

Accordingly, the weak base resin generally needs to be effective under neutral or slightly acidic conditions, and the corresponding anion with stronger acidity in the substance is easier to be adsorbed, so in some embodiments, the pH of the acidified solution is preferably 2 to 7, and more preferably 2 to 5.

Specifically, the specific process of step (3) is as follows: the acidified solution is passed through a device containing the basic resin at a flow rate of 6-15 mL/min.

The adsorption rate of the alkaline resin on substances such as isethionate, di-taurate, tri-taurate, sulfate, hydrochloride and the like in the acidizing fluid can reach more than 90%, so that the content of substances such as alkali metal isethionate, alkali metal ditaurinate, alkali metal tritaurinate, inorganic salts and the like in the refined fluid obtained in the step (3) is very low, and therefore, the viscosity degree of the solution in the crystallization process in the step (4) is greatly reduced, the operation procedure of taurine crystallization is simplified, the yield of the taurine crystallization is improved, meanwhile, the content of the inorganic salts in the taurine is greatly reduced, and the purity of the taurine is improved.

Specifically, the crystallization method comprises intermittent crystallization, continuous crystallization and the like, wherein the mass concentration of taurine in the solution during the intermittent crystallization is 30-70%, the temperature is 25-30 ℃, the mass concentration of taurine in the solution during the continuous crystallization is 40-60%, and the temperature is 50-70 ℃.

It is worth further elucidating that: and (3) when the acidification liquid with the pH value less than or equal to 8 is treated by adopting the alkaline resin, the hydroxide ions in the alkaline resin are exchanged into other acidic anions, so that the alkaline resin forms strong acid and weak alkaline resin and shows acidity. Therefore, after the alkaline resin is used for treating the acidizing fluid with the pH value less than or equal to 8, the alkaline resin is washed by alkaline solution, after the alkaline resin is washed, the hydroxide ions exchange acid anions, the acid anions are recovered to be the weak alkaline resin for repeated use, and eluent is obtained.

Wherein the alkaline solution comprises one of ammonia water and alkaline solution. When the basic solution is aqueous ammonia, the eluent includes ammonium ditetrasulfonate, ammonium trinitrate, ammonium sulfate, etc., and when the basic solution is an alkaline solution, the eluent includes alkali metal ditaurinate, alkali metal tritaurinate, inorganic salts, etc.

In order to increase the yield of the ammonolysis, the eluate may be directly recycled to step (1) for ammonolysis. In this case, since the substance components in the eluent are the same as those in the ammonolysis reaction when washing with an alkali solution, washing with an alkali solution is preferable, and a sodium hydroxide solution, an aqueous solution of sodium carbonate, or the like is more preferable.

Further, before the eluent is recycled to the step (1), the method also comprises a step of desalting the eluent to remove most inorganic salts and prevent inorganic salts from forming and accumulating to block equipment.

Further, the mother liquor remaining after the crystallization in the step (4) can be further recycled.

In this embodiment, after the acidified solution is subjected to the basic resin adsorption treatment in step (3), anions of the alkali metal isethionate, alkali metal ditaurinate, alkali metal tritaurinate, inorganic salts, and the like are adsorbed on the basic resin, and metal cations (such as sodium ions) are still present in the purified solution through the basic resin and form alkali metal taurate with taurate ions, thereby reducing the crystal yield of taurine.

Therefore, in order to avoid the formation of sodium taurate from the metal cations and tauride ions, thereby reducing the crystallization yield of taurine, embodiments two and three are also provided to remove the metal cations.

The second embodiment:

in this embodiment, in addition to the first embodiment, the step (3) further includes treating the acidified liquid with the basic resin and then treating the acidified liquid with the first acidic resin. Accordingly, the hydrogen ions on the first acidic resin are further exchanged with the metal cations, so that the metal cations are adsorbed on the first acidic resin, and the hydrogen ions are exchanged, so that the alkali metal isethionate, alkali metal ditaurinate, alkali metal tritaurinate, and inorganic salts in the acidified solution are adsorbed on the basic resin and the first acidic resin in step (3), respectively, to obtain a purified solution with a very low impurity content. Further, the crystallization yield of taurine in the step (4) is improved.

Specifically, the specific process of treating with the first acidic resin is as follows: the pre-purified solution after the treatment with the basic resin is passed through an apparatus containing the first acidic resin at a flow rate of 6 to 15 mL/min.

Further, in the step (3), after the first acidic resin is treated, the first acidic resin is washed with an acidic solution, so that hydrogen ions in the acidic solution exchange metal ions on the first acidic resin, the acidity of the first acidic resin is recovered, and meanwhile, an inorganic salt is obtained, and the inorganic salt can be converted into a usable raw material, so that the recycling of the material is realized, and the cost is saved.

The third embodiment is as follows:

in the present embodiment, in addition to the first embodiment, in the step (2), the ammonolysis solution is acidified by the second acidic resin, that is, hydrogen ions on the second acidic resin are exchanged with metal cations in the ammonolysis solution, so that the metal cations are adsorbed on the first acidic resin, and the obtained acidified solution contains taurine, ditaurine, tritaurine, isethionic acid and the like, while the generation of inorganic salts such as sulfate, sulfite, hydrochloride and the like is avoided.

Further, after the second acidic resin acidifies the ammonolysis solution, the method also comprises the step of using an acidic solution, preferably SO₂The second acidic resin is washed by the aqueous solution so that hydrogen ions in the acid solution exchange metal cations on the second acidic resin to restore the acidity of the second acidic resin, and the washing solution can be applied to the addition reaction.

Hereinafter, the method for crystallizing taurine provided by the present invention will be further described with reference to the following specific examples.

Example 1

42.45g of hydroxyethyl sodium sulfonate is weighed, dissolved by 350g of saturated ammonia water, enters an ammonification reactor, the temperature is raised to 200 ℃, the pressure is raised to 20MPa, and after reaction for 1 hour, ammonia is removed by flash evaporation to obtain ammonification solution. And acidifying the ammonolysis solution by using concentrated sulfuric acid until the pH value is 5.0 to obtain acidified solution. The acidified solution was passed through a weakly basic resin column and discharged at a flow rate of 7mL/min to obtain 308.45g of a purified solution. Heating the refined liquid to 60 ℃, concentrating under reduced pressure under the vacuum degree of-0.06 to-0.08 MPa until the concentration of taurine is 60%, slowly cooling to 25 ℃, preserving heat for 1 hour, filtering, and drying a filter cake to obtain 25.94g of a crude product of taurine.

The weakly basic resin is eluted by 300g of saturated ammonia water, and the eluent is mechanically applied to the next batch of ammonolysis reaction. The content of the obtained crude taurine is 98.0%, the crystallization yield is 92.1%, and the total adsorption rate of ditaurine, tritaurine and isethionic acid reaches 97.2%.

Example 2

42.45g of hydroxyethyl sodium sulfonate is weighed, dissolved by 348g of saturated ammonia water, enters an ammonification reactor, the temperature is increased to 280 ℃, the pressure is increased to 18MPa, and after reaction for 1 hour, ammonia is removed by flash evaporation to obtain ammonification solution. And acidifying the ammonolysis solution by using concentrated sulfuric acid until the pH value is 8.0 to obtain acidified solution. The acidified solution was passed through a strong basic resin column and discharged at a flow rate of 7mL/min to obtain 305.86g of a purified solution. Heating the refined liquid to 60 ℃, concentrating under reduced pressure under the vacuum degree of-0.06 to-0.08 MPa until the concentration of taurine is 50%, slowly cooling to 30 ℃, preserving heat for 1 hour, filtering, and drying a filter cake to obtain 25.07g of crude taurine.

The strongly basic resin was washed with 290g of 1% NaOH aqueous solution, and the eluate was desalted and concentrated and then used in the next ammonolysis reaction. The content of the obtained crude taurine is 99.1%, the crystallization yield is 90%, and the total adsorption rate of the ditaurine, the tritaurine and the isethionic acid reaches 94.6%.

Example 3

42.45g of hydroxyethyl sodium sulfonate is weighed, dissolved by 350g of saturated ammonia water, enters an ammonification reactor, the temperature is increased to 250 ℃, the pressure is increased to 14MPa, and after reaction for 1 hour, ammonia is removed by flash evaporation to obtain ammonification solution. And acidifying the ammonolysis solution by using concentrated sulfuric acid until the pH value is 7.0 to obtain acidified solution. The acidified solution was passed through a column of weakly basic resin and was discharged at a flow rate of 7mL/min to obtain 311.23g of a pre-refined solution. The pre-refined liquid enters a strong acid resin column and flows out at the flow rate of 7mL/min to obtain the refined liquid. And heating the refined liquid to 70 ℃, concentrating under reduced pressure under the vacuum degree of-0.06 to-0.08 MPa until the concentration of taurine is 65%, slowly cooling to 30 ℃, preserving heat for 1 hour, filtering, and drying a filter cake to obtain 27.38g of a crude product of taurine.

The weakly basic resin is washed by 300g of saturated ammonia water, and the eluent is mechanically applied to the next batch of ammonolysis reaction. The strong acid resin was washed with 200mL of 1% sulfuric acid, yielding a small amount of sodium sulfate. The content of the obtained crude taurine is 98.2%, the crystallization yield is 97.4%, and the total adsorption rate of ditaurine, tritaurine and isethionic acid reaches 95.3%.

Example 4

42.45g of hydroxyethyl sodium sulfonate is weighed, dissolved by 355g of saturated ammonia water, enters an ammonification reactor, the temperature is raised to 230 ℃, the pressure is raised to 17MPa, and after reaction for 1 hour, ammonia is removed by flash evaporation to obtain ammonification solution. And acidifying the ammonolysis solution by using concentrated sulfuric acid until the pH value is 7.0 to obtain acidified solution. The acidified solution was passed through a column of weakly basic resin and was discharged at a flow rate of 7mL/min to obtain 313.65g of a pre-refined solution. The pre-refined solution enters a weak acid resin column and flows out at the flow rate of 7mL/min to obtain the refined solution. And heating the refined liquid to 65 ℃, concentrating under reduced pressure under the vacuum degree of-0.06 to-0.08 MPa until the concentration of taurine is 60%, slowly cooling to 25 ℃, preserving heat for 1 hour, filtering, and drying a filter cake to obtain 26.40g of a crude taurine product.

The weakly basic resin was washed with 290g of 1% NaOH, and the eluate was desalted and concentrated before being used in the next ammonolysis reaction. The weakly acidic resin was regenerated with 200mL 1% sulfuric acid, yielding a small amount of sodium sulfate. The content of the obtained crude taurine is 99.0 percent, the crystallization yield is 94.7 percent, and the total adsorption rate of the ditaurine, the tritaurine and the isethionic acid reaches 94.8 percent.

Example 5

42.45g of hydroxyethyl sodium sulfonate is weighed, dissolved by 350g of saturated ammonia water, enters an ammonification reactor, the temperature is raised to 230 ℃, the pressure is raised to 19MPa, and after reaction for 1 hour, ammonia is removed by flash evaporation to obtain ammonification solution. And introducing the ammonolysis solution into a weak acid resin column, and acidifying until the pH value is 6.0 to obtain an acidified solution. The acidified solution was then passed through a weakly basic resin column at a flow rate of 7mL/min to obtain 310.26g of a purified solution. Heating the refined liquid to 60 ℃, concentrating under reduced pressure under the vacuum degree of-0.06 to-0.08 MPa until the concentration of taurine is 50%, slowly cooling to 20 ℃, preserving heat for 1 hour, filtering, and drying a filter cake to obtain 25.26g of crude taurine.

The weakly basic resin is washed by 280g of 2% sodium carbonate aqueous solution, and the eluent is desalted and concentrated and then is applied to next ammonolysis reaction. The weakly acidic resin is cleaned by sulfurous acid, and the cleaning solution is applied to the addition reaction. The content of the obtained crude taurine is 99.2%, the crystallization yield is 90.8%, and the total adsorption rate of ditaurine, tritaurine and isethionic acid reaches 96.2%.

Example 6

42.45g of hydroxyethyl sodium sulfonate is weighed, dissolved by 350g of saturated ammonia water, enters an ammonification reactor, the temperature is increased to 240 ℃, the pressure is increased to 18MPa, and after reaction for 1 hour, ammonia is removed by flash evaporation to obtain ammonification solution. And introducing the ammonolysis solution into a weak acid resin column, and acidifying until the pH value is 5.0 to obtain an acidified solution. And enabling the acidified solution to enter a weakly alkaline resin column, passing through the column, flowing out at the flow rate of 7mL/min to obtain 309.58g of refined solution, heating the refined solution to 70 ℃, concentrating under reduced pressure at the vacuum degree of-0.06 to-0.08 MPa until the concentration of taurine is 40%, slowly cooling to 20 ℃, preserving heat for 1 hour, filtering, and drying a filter cake to obtain 25.02g of crude taurine.

The weakly basic resin is washed by 300g of saturated ammonia water, and the eluent is mechanically applied to the next batch of ammonolysis reaction. The weakly acidic resin is cleaned by sulfurous acid, and the cleaning solution is applied to the addition reaction. The content of the obtained crude taurine is 99.3 percent, the crystallization yield is 90 percent, and the total adsorption rate of ditaurine, tritaurine and isethionic acid reaches 97.0 percent.

Comparative example 1

42.45g of hydroxyethyl sodium sulfonate is weighed, dissolved by 350g of saturated ammonia water, enters an ammonification reactor, the temperature is raised to 200 ℃, the pressure is raised to 20MPa, and after reaction for 1 hour, ammonia is removed by flash evaporation to obtain ammonification solution. And acidifying the ammonolysis solution by using concentrated sulfuric acid until the pH value is 5.0 to obtain acidified solution. Heating the acidizing fluid to 60 ℃, concentrating under reduced pressure under the vacuum degree of-0.06 to-0.08 MPa until the concentration of taurine is 60%, and slowly cooling to 25 ℃, wherein the system is basically solidified and can not be filtered.

Comparative example 2

42.45g of hydroxyethyl sodium sulfonate is weighed, dissolved by 350g of saturated ammonia water, enters an ammonification reactor, the temperature is raised to 200 ℃, the pressure is raised to 20MPa, and after reaction for 1 hour, ammonia is removed by flash evaporation to obtain ammonification solution. And acidifying the ammonolysis solution by using concentrated sulfuric acid until the pH value is 7.0 to obtain acidified solution. Heating the acidified solution to 60 ℃, concentrating under reduced pressure under the vacuum degree of-0.06 to-0.08 MPa until the concentration of taurine is 30%, slowly cooling to 25 ℃, preserving heat for 1 hour, filtering, and drying a filter cake to obtain 21.05g of a crude product of taurine. The content of the crude taurine obtained is 90.1%, and the yield is 52.9%.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.