LU505290A1 - Method for purifying L-lactic acid - Google Patents
Method for purifying L-lactic acid Download PDFInfo
- Publication number
- LU505290A1 LU505290A1 LU505290A LU505290A LU505290A1 LU 505290 A1 LU505290 A1 LU 505290A1 LU 505290 A LU505290 A LU 505290A LU 505290 A LU505290 A LU 505290A LU 505290 A1 LU505290 A1 LU 505290A1
- Authority
- LU
- Luxembourg
- Prior art keywords
- exchange resin
- resin column
- anion
- cation
- lactic acid
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 194
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical compound C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 title claims abstract description 48
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 claims abstract description 166
- 239000003957 anion exchange resin Substances 0.000 claims abstract description 158
- 239000003729 cation exchange resin Substances 0.000 claims abstract description 129
- 239000000463 material Substances 0.000 claims abstract description 120
- 238000004519 manufacturing process Methods 0.000 claims abstract description 64
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 62
- 238000011001 backwashing Methods 0.000 claims abstract description 25
- 230000001172 regenerating effect Effects 0.000 claims abstract description 4
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims description 102
- 239000002253 acid Substances 0.000 claims description 94
- 239000000243 solution Substances 0.000 claims description 77
- 239000003513 alkali Substances 0.000 claims description 59
- 239000011347 resin Substances 0.000 claims description 54
- 229920005989 resin Polymers 0.000 claims description 54
- 239000004310 lactic acid Substances 0.000 claims description 53
- 235000014655 lactic acid Nutrition 0.000 claims description 53
- 230000008929 regeneration Effects 0.000 claims description 31
- 238000011069 regeneration method Methods 0.000 claims description 31
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 24
- 241001550224 Apha Species 0.000 claims description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 12
- 238000000079 presaturation Methods 0.000 claims description 12
- 238000009833 condensation Methods 0.000 claims description 10
- 230000005494 condensation Effects 0.000 claims description 10
- 239000007864 aqueous solution Substances 0.000 claims description 9
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 6
- 238000009738 saturating Methods 0.000 abstract 2
- 238000004064 recycling Methods 0.000 abstract 1
- 238000005342 ion exchange Methods 0.000 description 85
- 239000010410 layer Substances 0.000 description 49
- 239000003456 ion exchange resin Substances 0.000 description 37
- 229920003303 ion-exchange polymer Polymers 0.000 description 37
- 239000002699 waste material Substances 0.000 description 30
- -1 iron ions Chemical class 0.000 description 28
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 20
- 238000002156 mixing Methods 0.000 description 18
- 238000001179 sorption measurement Methods 0.000 description 16
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- 229910052742 iron Inorganic materials 0.000 description 12
- 239000011241 protective layer Substances 0.000 description 12
- 229920006395 saturated elastomer Polymers 0.000 description 12
- 150000002500 ions Chemical class 0.000 description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 9
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Natural products OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 8
- 238000004042 decolorization Methods 0.000 description 6
- 238000000605 extraction Methods 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 238000002791 soaking Methods 0.000 description 5
- RGHNJXZEOKUKBD-UHFFFAOYSA-N D-gluconic acid Natural products OCC(O)C(O)C(O)C(O)C(O)=O RGHNJXZEOKUKBD-UHFFFAOYSA-N 0.000 description 4
- RGHNJXZEOKUKBD-SQOUGZDYSA-N Gluconic acid Natural products OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C(O)=O RGHNJXZEOKUKBD-SQOUGZDYSA-N 0.000 description 4
- 150000001413 amino acids Chemical class 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 238000000855 fermentation Methods 0.000 description 4
- 230000004151 fermentation Effects 0.000 description 4
- 239000000174 gluconic acid Substances 0.000 description 4
- 235000012208 gluconic acid Nutrition 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 230000003204 osmotic effect Effects 0.000 description 4
- 235000006408 oxalic acid Nutrition 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000000049 pigment Substances 0.000 description 4
- 239000011148 porous material Substances 0.000 description 4
- 230000001681 protective effect Effects 0.000 description 4
- 230000000630 rising effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000005341 cation exchange Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000005374 membrane filtration Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000000199 molecular distillation Methods 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- 229920002261 Corn starch Polymers 0.000 description 1
- 241000124008 Mammalia Species 0.000 description 1
- CZMRCDWAGMRECN-UHFFFAOYSA-N Rohrzucker Natural products OCC1OC(CO)(OC2OC(CO)C(O)C(O)C2O)C(O)C1O CZMRCDWAGMRECN-UHFFFAOYSA-N 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- 229930006000 Sucrose Natural products 0.000 description 1
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 description 1
- 238000005903 acid hydrolysis reaction Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000005349 anion exchange Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000008120 corn starch Substances 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000004060 metabolic process Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 235000013379 molasses Nutrition 0.000 description 1
- 231100000957 no side effect Toxicity 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 238000004094 preconcentration Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012797 qualification Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 239000005720 sucrose Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/47—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Abstract
Provided is a method for purifying L-lactic acid, comprising the following steps: (1) a production procedure; (2) a circulating procedure; (3) a material off procedure: using water to conduct the material off process on a cation exchange resin column and an anion exchange resin column which are switched from the production process, and recycling the jacked material; (4) a backwashing procedure; (5) a regenerating procedure; (6) a rinsing procedure; (7) a pre-saturating procedure; and (8) a material on procedure: The cation exchange resin column and the anion exchange resin column are continuously switched during the production procedure, the circulating procedure, the material off procedure, the backwashing procedure, the regenerating procedure, the rinsing procedure, the pre-saturating procedure, and the material on procedure.
Description
Method for purifying L-lactic acid LU505290
The present invention relates to a lactic acid separation and purification technology, in particular to a method for purifying L-lactic acid.
L-lactic acid: molecular formula: C3HsOs3, boiling point: 125 °C. L-lactic acid is a kind of organic acid refined by biological fermentation from corn starch, raw sucrose, beet sugar or molasses as raw materials. It is a colorless, clear, viscous liquid, and its aqueous solution is acidic.
It can be freely mixed with water, ethanol or ether, and is insoluble in chloroform. Because of its levorotatory characteristics, it has good biological compatibility, can be compatible with mammals, can directly participate in human metabolism, and has no side effects. It is widely used in food, medicine and other fields.
The production of L-lactic acid comprises saccharifying a starch-containing raw material, then inoculating with a lactic acid bacteria strain and performing fermentation. After the fermentation, it undergoes acid hydrolysis, filtration, pre-concentration, decolorization, ion- exchange, membrane filtration, concentration, molecular distillation, and so on to obtain a final product. The costs of membrane filtration, concentration, and molecular distillation after ion- exchange are relatively high.
Contents of the present invention
In order to provide a new method for purifying L-lactic acid, the present invention adopts a method with multiple steps of ion-exchange, which results in a higher yield.
The technical solution of the present invention is: a method for purifying L-lactic acid, comprising the following steps: (1) Production process: feeding a crude lactic acid solution into a cation-exchange resin column unit and an anion-exchange resin column unit arranged in series to obtain a purified lactic acid solution; in which the crude lactic acid solution is obtained by allowing a L-lactic acid fermentation liquid to undergo plate and frame filtration, evaporation, hydrolysis and decolorization; (2) Circulation process: feeding the crude lactic acid solution into an anion-exchange resin column switched from the production process, and circulating the effluent in the anion-exchange resin column until a sulfate ion is detected in the effluent, and the circulation process ends; 1 51826873-1
(3) Material off process: carrying out material off process in a cation-exchange resin column . . . . . LU505290 switched from the production process and an anion-exchange resin column switched from the circulation process respectively by using water, and recovering the replaced material; (4) Backwashing process: carrying out backwashing of a cation-exchange resin column and an anion-exchange resin column switched from the material off process by using water; (5) Regeneration process: regenerating a cation-exchange resin column and an anion- exchange resin column switched from the backwashing process by using regeneration solutions, in which the regeneration solution for the cation-exchange resin column is a diluted acid aqueous solution, and the regeneration solution for the anion-exchange resin column is a diluted alkali aqueous solution; (6) Rinsing process: rinsing an anion-exchange resin column and a cation-exchange resin column switched from the regeneration process by using water; (7) Pre-saturation process: by using a thin acid solution, replacing the water in an anion- exchange resin column and a cation-exchange resin column that have been rinsed; in the pre- saturation process, by using the thin acid solution, firstly pressing out the water with a unqualified pH value or a unqualified ion content to reduce the amount of material to be loaded; (8) Material on process: by using the crude lactic acid solution, carrying out material on process in a cation-exchange resin column after the pre-saturation process, and by using an effluent of the cation-exchange resin column unit in the production process, carrying out material on process in an anion-exchange resin column;
Wherein, the cation-exchange resin columns and the anion-exchange resin columns in the production process, circulation process, material off process, backwashing process, regeneration process, rinsing process, pre-saturation process and material on process are switched continuously.
The cation-exchange resin column unit comprises three stages of cation-exchange resin column subunits arranged in series, and each stage of cation-exchange resin column subunits comprises at least two cation-exchange resin columns arranged in parallel; the anion-exchange resin column unit comprises three stages of anion-exchange resin column subunits arranged in series, and each stage of anion-exchange resin column subunits comprises at least two anion- exchange resin columns arranged in parallel.
The anion-exchange resin column is OH type D319 macroporous weak basic anion-exchange resin.
In the material on process, firstly discharging the effluents from the cation-exchange resin column and the anion-exchange resin column as wastewater; when the effluents from the cation- 2 518268731 exchange resin column and the anion-exchange resin column have a lactic acid mass concentration
LU505290 of > 0.5%, closing a drain valve for the wastewater, and opening a thin acid valve to introduce the effluents into a thin acid tank; when the effluents from the cation-exchange resin column and the anion-exchange resin column have a lactic acid mass concentration of > 2.5%, closing the thin acid valve and opening a discharge valve.
Feeding the discharged material from the material off process into the thin acid tank.
Connecting a feed pipe of the anion-exchange resin column and the cation-exchange resin column in the pre-saturation process each with the thin acid tank.
The crude lactic acid as feedstock in the production process has a mass concentration of 17% to 22%, and a chroma of <300 APHA.
The feedstock in the production process has a flow rate controlled at 15 to 30 m%h.
The material off process uses a steam condensation water or hot pure water, and the water has a temperature of 45 to 50 °C. The water at this temperature helps to elute the acid from the resin.
The material off process is completed when the discharged material solution of the material off process has a lactic acid mass concentration of <0.5%.
The diluted acid aqueous solution is a diluted hydrochloric acid solution, and the diluted hydrochloric acid solution has a mass percent concentration of 3.5 to 5 %.
The diluted alkali aqueous solution is a sodium hydroxide solution, and the sodium hydroxide solution has a mass percent concentration of 5 to 6 %.
The regeneration solution added in the regeneration process is 1.5 to 2 times the volume of the resin, and is used for soaking for 2 to 4 hours.
Mixing a discharged acid from the rinsing process with a concentrated acid solution in the regeneration solution and then adding the mixture to the cation-exchange resin column in the regeneration process; mixing a discharged alkali from the rinsing process with a concentrated alkali solution in the regeneration solution and then adding the mixture to the anion-exchange resin column; by using a discharged water from rising step 3 directly backwashing the cation-exchange column in the backwashing process; by using the discharged water from rising step 3 backwashing the anion-exchange column.
In the rinsing process, the rising is completed when the effluent from the cation-exchange resin column has a pH value of 3 to 4, and the rising is completed when the anion-exchange resin column has a pH value of 8 to 9. 3 518268731
The thin acid solution is a solution with a lactic acid content of less than 2.5% produced from
LU505290 the anion-exchange resin column and the cation-exchanges resin column during the material off process and the material on process.
Figure 1 shows a schematic flow diagram of the method of the present invention.
Figure 2 shows a process flow diagram of the production process.
Figure 3 shows a schematic diagram of resin layers in the ion-exchange resin column.
Specific Models for Carrying Out the present invention
The embodiments of the present invention will be clearly and completely described below in conjunction with the examples and drawings. Apparently, the described examples are only some of the examples of the present invention, not all of them. The following description of at least one exemplary embodiment is merely illustrative in nature and in no way taken as limiting the present invention, its application or uses. Based on the examples of the present invention, all other examples obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.
An extraction method for purifying L-lactic acid solution, as shown in Figure 1, comprises the following steps, (1) Production process, comprising a. One-stage ion-exchange: A crude lactic acid solution with a concentration of 17 to 22 % and a chroma of <300 APHA pre-treated by a carbon column is pumped into a cation-exchange resin column subunit and an anion-exchange resin column subunit arranged in series by a centrifugal pump to undergo ion-exchange, in which the flow rate is controlled at 15 to 30 m%h.
When the discharged ions reach a chroma < 50 to 100 APHA, it is discharged into a one-stage ion- exchange material tank. One cation-exchange resin column subunit comprises a plurality of cation- exchange resin columns arranged in parallel, and one anion-exchange resin column subunit comprises a plurality of anion-exchange resin columns arranged in parallel. b. Two-stage ion-exchange: It can play a protective role when the discharged material index of the one-stage ion-exchange is unqualified. In the two-stage ion-exchange, two cation-exchange resin column subunits are arranged in series and then arranged in series with two anion-exchange resin column subunits arranged in series. 4 51826873-1 c. Three-stage ion-exchange: It ensures that the discharged material from ion-exchange is qualified in terms of ions and chroma (iron ions < 2ppm, chloride ions < 2ppm, sulfate radicals ©2200
Sppm, chroma < 50 to 100 APHA). In the three-stage ion-exchange, three cation-exchange resin column subunits are arranged in series and then arranged in series with three anion-exchange resin column subunits arranged in series.
According to the situation, the production process can adopt one-stage ion-exchange, two- stage ion-exchange or three-stage ion-exchange, and three-stage ion-exchange is preferred. The three-stage ion-exchange specifically comprises the following (as shown in Figure 2): the crude lactic acid solution after decolorization is pumped into a first cation-exchange resin column subunit, a second cation-exchange resin column subunit, and a third cation-exchange resin column subunit by a centrifugal pump at a flow rate of 15 to 30 m°/h, and then discharged into a transfer tank, and then pumped into a first anion-exchange resin column subunit, a second anion-exchange resin column subunit, and a third anion-exchange resin column subunit by a centrifugal pump at a flow rate of 15 to 30 m/h (wherein, in one example, the first cation-exchange resin column subunit consists of 5 cation-exchange resin columns arranged in parallel, and is arranged in series with the second cation-exchange resin column subunit consisting of 5 cation-exchange resin columns arranged in parallel, and then arranged in series with the third cation-exchange resin column subunit consisting of 5 cation-exchange resin columns arranged in parallel; after undergoing ion- exchange in the three cation-exchange resin column subunits, the material enters anion-exchange resin column subunits for ion-exchange, in which the first anion-exchange resin column subunit consists of 4 anion-exchange resin columns arranged in parallel, and is arranged in series with the second anion-exchange resin column subunit consisting of 4 anion-exchange resin columns arranged in parallel, and then arranged in series with the third anion-exchange resin column subunit consisting of 4 anion-exchange resin columns arranged in parallel), and the columns are controlled by an intelligent control system. (2) Circulation process: The anion-exchange resin columns selected in the actual production process are OH type D319 macroporous weak basic anion-exchange resin. This type of resin has larger physical pores, faster exchange speed, large exchange capacity, high regeneration rate, good organic pollution resistance, osmotic pressure resistance, impact change resistance and high physical strength. In addition to a large amount of lactic acid radicals, there are also small amounts of organic acid radicals such as oxalic acid radicals and gluconic acid radicals, sulfate radicals, chloride ions, amino acids, and negatively charged pigments, etc. in the crude lactic acid solution.
According to the adsorption selection order of weak basic anion-exchange resin for acid radicals, namely, OH>SO,">lactate radical>NO;>CI>F", a large amount of lactate ions will be adsorbed on the anion-exchange resin during the production process, and then the lactate ions adsorbed on 518268731 the anion-exchange resin will be exchanged by the sulfate ions in the feedstock lactic acid solution, and combined with H” in the material to generate lactic acid. However, in the production process, 995290 we judge the failure of ion-exchange resin column by whether there is a chlorine ion outflowing from the outlet of the ion-exchange resin column. During the process that material passes through the ion-exchange resin column, the resin layer therein can be divided into three layers according to the adsorption capacity of resin (as shown in Figure 3), that is, the first layer is a saturated layer, the second layer is an ion-exchange layer, and the third layer is a protective layer. When the material is continuously introduced, the adsorption capacity of resin is gradually saturated, the saturated layer moves to the ion-exchange layer, the ion-exchange layer moves to the protective layer (the resin itself does not really move, and this is merely to express more vividly the change of the adsorption capacity of resin), the ion-exchange resin column will lose the protection of the protective layer and there will be leakage of chloride ions, and it will be judged that the ion- exchange column is invalid, but there are still lactate ions on the ion-exchange layer resin that have not been exchanged. At this time, the circulation of the anion-exchange resin column is initiated, until sulfate radicals flow out from the outlet of the ion-exchange resin column, it can be judged that the ion-exchange resin column is completely invalid, in such way, the yield of the ion- exchange resin column can be improved. (3) Material off process: Three columns arranged in series are used to push the material in a completely invalid ion-exchange resin column with steam condensation water or hot pure water (having a temperature of 45 to 50 °C) into a before-ion-exchange tank or a next spare column.
During the material off process, the concentration change at the outlet of the invalid column should be observed; when the concentration is < 2.5%, the material should be introduced into the thin acid tank; when the concentration is < 0.5%, the material off process is completed. (4) Backwashing process: The column in which the material off process is completed is backwashed with steam condensation water, and the purpose of which is to loosen the resin layer and remove broken resin particles and some impurities by backwashing. (5) Regeneration process: Waste acid and waste alkali are used for blending concentrated acid and concentrated alkali, respectively, in which the waste acid and waste alkali discharged during the rinsing process are directly introduced into pipelines of concentrated acid and concentrated alkali and undergo blending in mixers, three columns arranged in series are herein adopted as well, which improves the utilization rates of acid and alkali and reduces the production cost of factory.
Hydrochloric acid with a concentration of 3.5 to 5 % is added into cation-exchange resin column, and sodium hydroxide with a concentration of 5 to 6 % is added into anion-exchange resin column.
The acid and alkali added have a volume 1.5 to 2 times that of the resin, and the soaking is 6 518268731 performed for 2 to 4 hours. Since the recovered acid and alkali are used for blending the concentrated acid and concentrated alkali, the consumption of acid and alkali is reduced. 505290 (6) Rinsing process: Three columns arranged in series are adopted as well, the soaked columns are rinsed with hot pure water, and the waste acid and alkali discharged during the rinsing process are reused, in which they are directly introduced into an inlet of a regeneration column and used by blending with the concentrated acid and alkali, respectively. The rinsing process is divided into two steps. In the first step, the waste acid or alkali in the column is rinsed out until the cation- exchange resin column is rinsed to have a pH of 3 to 4, or the anion-exchange resin column is rinsed to have a pH of 8 to 9, then the second step is performed. In the second step, the water discharged during the rinsing process is directly introduced into a column for the backwashing process, and this step is also performed to make full use of water, thereby reducing the amount of water used and production costs. After the rinsing process is completed, the cation-exchange resin column and anion-exchange resin column cannot be used in the production process until the detection shows iron ions < 2ppm and chloride ions < 2ppm. The water consumption is about 4 to 8 times the volume of the resin. (7) Pre-saturation process: The water in the rinsed column is replaced with a thin acid solution (having a concentration of < 2.5%), which reduces the burden of concentration process, thereby reducing production costs. (8) Material on process: When a cation-exchange resin column undergoes material on process, a crude lactic acid solution pre-treated with a carbon column to have a concentration of 17% to 22% and a chroma of < 300 APHA is pumped into the cation-exchange resin column by a centrifugal pump to perform material on process; when an anion-exchange resin column undergoes material on process, a lactic acid solution treated with the third cation-exchange resin column subunit to have a concentration of 20% and iron ions of <Sppm is pumped into the anion-exchange resin column by a centrifugal pump to perform material on process, when the concentration reaches >0.5% at the outlet of the cation-exchange resin column or the anion-exchange resin column during the material on process, a drain valve is switched to a thin acid valve so that the discharged solution is sent to the thin acid tank; when the concentration reaches >2.5% at the outlet of ion-exchange resin column, the thin acid valve is closed and switched to a third discharge valve, and the production process is formally performed.
The automatic control system is capable of executing start/stop, flow control, real-time display and alarm of current, power, frequency, status and so on of pumps, as well as opening, status and running time of valves, and the like. 7 518268731
The work efficiency is improved, the consumption of water, alkali, acid and steam in production is reduced, and the product yield is elevated. 505290
Example 1
An extraction method for purifying L-lactic acid solution, as shown in Figure 1, comprised the following steps, (1) Production process, comprising a. One-stage ion-exchange: A crude lactic acid solution with a concentration of 22% and a chroma of <300 APHA pre-treated by a carbon column was pumped into a cation-exchange resin column subunit and an anion-exchange resin column subunit arranged in series by a centrifugal pump to undergo ion-exchange, in which the flow rate was controlled at 15 m°/h. When the discharged ions reached a chroma < 50 to 100 APHA, it was discharged into a one-stage ion- exchange material tank. One cation-exchange resin column subunit comprised a plurality of cation-exchange resin columns arranged in parallel, and one anion-exchange resin column subunit comprised a plurality of anion-exchange resin columns arranged in parallel. b. Two-stage ion-exchange: It could play a protective role when the discharged material index of the one-stage ion-exchange was unqualified. In the two-stage ion-exchange, two cation- exchange resin column subunits were arranged in series and then arranged in series with two anion- exchange resin column subunits arranged in series. c. Three-stage ion-exchange: It could ensure that the discharged material from ion-exchange was qualified in terms of ions and chroma. In the three-stage ion-exchange, three cation-exchange resin column subunits were arranged in series and then arranged in series with three anion- exchange resin column subunits arranged in series.
The three-stage ion-exchange used in the production process specifically comprised the following (as shown in Figure 2): the crude lactic acid solution after decolorization was pumped into a first cation-exchange resin column subunit, a second cation-exchange resin column subunit, and a third cation-exchange resin column subunit by a centrifugal pump at a flow rate of 15 m°/h, and then discharged into a transfer tank, and then pumped into a first anion-exchange resin column subunit, a second anion-exchange resin column subunit, and a third anion-exchange resin column subunit by a centrifugal pump at a flow rate of 15 m°/h (wherein, in one example, the first cation- exchange resin column subunit consisted of 5 cation-exchange resin columns arranged in parallel, and was arranged in series with the second cation-exchange resin column subunit consisting of 5 cation-exchange resin columns arranged in parallel, and then arranged in series with the third 8 51826873-1 cation-exchange resin column subunit consisting of 5 cation-exchange resin columns arranged in parallel; after undergoing ion-exchange in the three cation-exchange resin column subunits, the 505290 material entered anion-exchange resin column subunits for ion-exchange, in which the first anion- exchange resin column subunit consisted of 4 anion-exchange resin columns arranged in parallel,
and was arranged in series with the second anion-exchange resin column subunit consisting of 4 anion-exchange resin columns arranged in parallel, and then arranged in series with the third anion- exchange resin column subunit consisting of 4 anion-exchange resin columns arranged in parallel),
and the columns were controlled by an intelligent control system.
(2) Circulation process: The anion-exchange resin columns selected in the actual production process were OH type D319 macroporous weak basic anion-exchange resin.
This type of resin had larger physical pores, faster exchange speed, large exchange capacity, high regeneration rate, good organic pollution resistance, osmotic pressure resistance, impact change resistance and high physical strength.
In addition to a large amount of lactic acid radicals, there were also small amounts of organic acid radicals such as oxalic acid radicals and gluconic acid radicals, sulfate radicals, chloride ions, amino acids, and negatively charged pigments, etc. in the crude lactic acid solution.
According to the adsorption selection order of weak basic anion-exchange resin for acid radicals, namely, OH>SO4,">lactate radical>NO3;>CI1>F", a large amount of lactate ions would be adsorbed on the anion-exchange resin during the production process, and then the lactate ions adsorbed on the anion-exchange resin would be exchanged by the sulfate ions in the feedstock lactic acid solution, and combined with H in the material to generate lactic acid.
However, in the production process, we judged the failure of ion-exchange resin column by whether there was a chlorine ion outflowing from the outlet of the ion-exchange resin column.
During the process that material passed through the ion-exchange resin column, the resin layer therein could be divided into three layers according to the adsorption capacity of resin (as shown in Figure 3), that was, the first layer was a saturated layer, the second layer was an ion-exchange layer, and the third layer was a protective layer.
When the material was continuously introduced, the adsorption capacity of resin was gradually saturated, the saturated layer moved to the ion-exchange layer, the ion- exchange layer moved to the protective layer (the resin itself did not really move, and this was merely to express more vividly the change of the adsorption capacity of resin), the ion-exchange resin column would lose the protection of the protective layer and there would be leakage of chloride ions, and it would be judged that the ion-exchange column was invalid, but there were still lactate ions on the ion-exchange layer resin that had not been exchanged.
At this time, the circulation of the anion-exchange resin column was initiated, until sulfate radicals flowed out from the outlet of the ion-exchange resin column, it could be judged that the ion-exchange resin column was completely invalid, in such way, the yield of the ion-exchange resin column could be improved.
9 518268731
(3) Material off process: Three columns arranged in series were used to push the material in a completely invalid ion-exchange resin column with steam condensation water or hot pure water 205290 (having a temperature of 45 °C) into a before-ion-exchange tank or a next spare column.
During the material off process, the concentration change at the outlet of the invalid column should be observed; when the concentration was < 2.5%, the material should be introduced into the thin acid tank; when the concentration was < 0.5%, the material off process was completed.
(4) Backwashing process: The column in which the material off process was completed was backwashed with steam condensation water, and the purpose of which was to loosen the resin layer and remove broken resin particles and some impurities by backwashing.
(5) Regeneration process: Waste acid and waste alkali were used for blending concentrated acid and concentrated alkali, respectively, in which the waste acid and waste alkali discharged during the rinsing process were directly introduced into pipelines of concentrated acid and concentrated alkali and underwent blending in mixers, three columns arranged in series were herein adopted as well, which improved the utilization rates of acid and alkali and reduced the production cost of factory.
Hydrochloric acid with a concentration of 3.5% was added into cation- exchange resin column, and sodium hydroxide with a concentration of 5% was added into anion- exchange resin column.
The acid and alkali added had a volume 1.5 to 2 times that of the resin, and the soaking was performed for 2 to 4 hours.
Since the recovered acid and alkali were used for blending the concentrated acid and concentrated alkali, the consumption of acid and alkali was reduced.
(6) Rinsing process: Three columns arranged in series were adopted as well, the soaked columns were rinsed with hot pure water, and the waste acid and the waste alkali discharged during the rinsing process were reused, in which they were directly introduced into an inlet of a regeneration column and used by blending with the concentrated acid and the concentrated alkali, respectively.
The rinsing process was divided into two steps.
In the first step, the waste acid or the waste alkali in the column was rinsed out until the cation-exchange resin column was rinsed to have a pH of 3 to 4, or the anion-exchange resin column was rinsed to have a pH of 8 to 9, then the second step was performed.
In the second step, the water discharged during the rinsing process was directly introduced into a column for the backwashing process, and this step was also performed to make full use of water, thereby reducing the amount of water used and production costs.
After the rinsing process was completed, the cation-exchange resin column and anion- exchange resin column could not be used in the production process until the detection showed iron ions < 2ppm and chloride ions < 2ppm.
The water consumption was about 4 to 8 times the volume of the resin.
51826873-1
(7) Pre-saturation process: The water in the rinsed column was replaced with a thin acid solution (having a concentration of < 2.5%), which reduced the burden of concentration process, thereby reducing production costs. (8) Material on process: When a cation-exchange resin column underwent material on process, a crude lactic acid solution pre-treated with a carbon column to have a concentration of 17% and a chroma of < 300 APHA was pumped into the cation-exchange resin column by a centrifugal pump to perform material on process; when an anion-exchange resin column underwent material on process, a lactic acid solution treated with the third cation-exchange resin column subunit to have a concentration of 20% and iron ions of <Sppm was pumped into the anion-exchange resin column by a centrifugal pump to perform material on process, when the concentration reached >0.5% at the outlet of the cation-exchange resin column or the anion-exchange resin column during the material on process, a drain valve was switched to a thin acid valve so that the discharged solution was sent to the thin acid tank; when the concentration reached >2.5% at the outlet of ion- exchange resin column, the thin acid valve was closed and switched to a third discharge valve, and the production process was formally performed.
The automatic control system was capable of executing start/stop, flow control, real-time display and alarm of current, power, frequency, status and so on of pumps, as well as opening, status and running time of valves, and the like.
The work efficiency was improved, the consumption of water, alkali, acid and steam in production was reduced, and the product yield was elevated.
Example 2
An extraction method for purifying L-lactic acid solution, as shown in Figure 1, comprised the following steps, (1) Production process, comprising a. One-stage ion-exchange: A crude lactic acid solution with a concentration of 22% and a chroma of <300APHA pre-treated by a carbon column was pumped into a cation-exchange resin column subunit and an anion-exchange resin column subunit arranged in series by a centrifugal pump to undergo ion-exchange, in which the flow rate was controlled at 30 m°/h. When the discharged ions reached a chroma < 50 to 100 APHA, it was discharged into a one-stage ion- exchange material tank. One cation-exchange resin column subunit comprised a plurality of cation-exchange resin columns arranged in parallel, and one anion-exchange resin column subunit comprised a plurality of anion-exchange resin columns arranged in parallel. 11 51826873-1 b. Two-stage ion-exchange: It could play a protective role when the discharged material index of the one-stage ion-exchange was unqualified. In the two-stage ion-exchange, two cations 505290 exchange resin column subunits were arranged in series and then arranged in series with two anion- exchange resin column subunits arranged in series. c. Three-stage ion-exchange: It could ensure that the discharged material from ion-exchange was qualified in terms of ions and chroma (iron ions < 2ppm, chloride ions < 2ppm, sulfate radicals < 5ppm, chroma < 50 to 100 APHA). In the three-stage ion-exchange, three cation-exchange resin column subunits were arranged in series and then arranged in series with three anion-exchange resin column subunits arranged in series.
The three-stage ion-exchange was adopted in the production process, in which the three-stage ion-exchange specifically comprised the following (as shown in Figure 2): the crude lactic acid solution after decolorization was pumped into a first cation-exchange resin column subunit, a second cation-exchange resin column subunit, and a third cation-exchange resin column subunit by a centrifugal pump at a flow rate of 30 m°/h, and then discharged into a transfer tank, and then pumped into a first anion-exchange resin column subunit, a second anion-exchange resin column subunit, and a third anion-exchange resin column subunit by a centrifugal pump at a flow rate of m°/h (wherein, in one example, the first cation-exchange resin column subunit consisted of 5 cation-exchange resin columns arranged in parallel, and was arranged in series with the second cation-exchange resin column subunit consisting of 5 cation-exchange resin columns arranged in parallel, and then arranged in series with the third cation-exchange resin column subunit consisting of 5 cation-exchange resin columns arranged in parallel; after undergoing ion-exchange in the three cation-exchange resin column subunits, the material entered anion-exchange resin column subunits for ion-exchange, in which the first anion-exchange resin column subunit consisted of 4 anion-exchange resin columns arranged in parallel, and was arranged in series with the second anion-exchange resin column subunit consisting of 4 anion-exchange resin columns arranged in parallel, and then arranged in series with the third anion-exchange resin column subunit consisting of 4 anion-exchange resin columns arranged in parallel), and the columns were controlled by an intelligent control system. (2) Circulation process: The anion-exchange resin columns selected in the actual production process were OH type D319 macroporous weak basic anion-exchange resin. This type of resin had larger physical pores, faster exchange speed, large exchange capacity, high regeneration rate, good organic pollution resistance, osmotic pressure resistance, impact change resistance and high physical strength. In addition to a large amount of lactic acid radicals, there were also small amounts of organic acid radicals such as oxalic acid radicals and gluconic acid radicals, sulfate radicals, chloride ions, amino acids, and negatively charged pigments, etc. in the crude lactic acid 12 518268731 solution.
According to the adsorption selection order of weak basic anion-exchange resin for acid radicals, namely, OH>SO,">lactate radical>NO;>CI>F", a large amount of lactate ions would 205690 be adsorbed on the anion-exchange resin during the production process, and then the lactate ions adsorbed on the anion-exchange resin would be exchanged by the sulfate ions in the feedstock lactic acid solution, and combined with H in the material to generate lactic acid.
However, in the production process, we judged the failure of ion-exchange resin column by whether there was a chlorine ion outflowing from the outlet of the ion-exchange resin column.
During the process that material passed through the ion-exchange resin column, the resin layer therein could be divided into three layers according to the adsorption capacity of resin (as shown in Figure 3), that was, the first layer was a saturated layer, the second layer was an ion-exchange layer, and the third layer was a protective layer.
When the material was continuously introduced, the adsorption capacity of resin was gradually saturated, the saturated layer moved to the ion-exchange layer, the ion- exchange layer moved to the protective layer (the resin itself did not really move, and this was merely to express more vividly the change of the adsorption capacity of resin), the ion-exchange resin column would lose the protection of the protective layer and there would be leakage of chloride ions, and it would be judged that the ion-exchange column was invalid, but there were still lactate ions on the ion-exchange layer resin that had not been exchanged.
At this time, the circulation of the anion-exchange resin column was initiated, until sulfate radicals flowed out from the outlet of the ion-exchange resin column, it could be judged that the ion-exchange resin column was completely invalid, in such way, the yield of the ion-exchange resin column could be improved.
(3) Material off process: Three columns arranged in series were used to push the material in a completely invalid ion-exchange resin column with steam condensation water or hot pure water (having a temperature of 50 °C) into a before-ion-exchange tank or a next spare column.
During the material off process, the concentration change at the outlet of the invalid column should be observed; when the concentration was < 2.5%, the material should be introduced into the thin acid tank; when the concentration was < 0.5%, the material off process was completed.
(4) Backwashing process: The column in which the material off process was completed was backwashed with steam condensation water, and the purpose of which was to loosen the resin layer and remove broken resin particles and some impurities by backwashing.
(5) Regeneration process: Waste acid and waste alkali were used for blending concentrated acid and concentrated alkali, respectively, in which the waste acid and waste alkali discharged during the rinsing process were directly introduced into pipelines of concentrated acid and concentrated alkali and underwent blending in mixers, three columns arranged in series were herein adopted as well, which improved the utilization rates of acid and alkali and reduced the production cost of factory.
Hydrochloric acid with a concentration of 5% was added into cation-
13 518268731 exchange resin column, and sodium hydroxide with a concentration of 6% was added into anion- exchange resin column.
The acid and alkali added had a volume 1.5 to 2 times that of the resin, 09290 and the soaking was performed for 2 to 4 hours.
Since the recovered acid and alkali were used for blending the concentrated acid and concentrated alkali, the consumption of acid and alkali was reduced.
(6) Rinsing process: Three columns arranged in series were adopted as well, the soaked columns were rinsed with hot pure water, and the waste acid and the waste alkali discharged during the rinsing process were reused, in which they were directly introduced into an inlet of a regeneration column and used by blending with the concentrated acid and the concentrated alkali, respectively.
The rinsing process was divided into two steps.
In the first step, the waste acid or the waste alkali in the column was rinsed out until the cation-exchange resin column was rinsed to have a pH of 3 to 4, or the anion-exchange resin column was rinsed to have a pH of 8 to 9, then the second step was performed.
In the second step, the water discharged during the rinsing process was directly introduced into a column for the backwashing process, and this step was also performed to make full use of water, thereby reducing the amount of water used and production costs.
After the rinsing process was completed, the cation-exchange resin column and anion- exchange resin column could not be used in the production process until the detection showed iron ions < 2ppm and chloride ions < 2ppm.
The water consumption was about 4 to 8 times the volume of the resin.
(7) Pre-saturation process: The water in the rinsed column was replaced with a thin acid solution (having a concentration of < 2.5%), which reduced the burden of concentration process, thereby reducing production costs.
(8) Material on process: When a cation-exchange resin column underwent material on process, a crude lactic acid solution pre-treated with a carbon column to have a concentration of 17-22% and a chroma of <300 APHA was pumped into the cation-exchange resin column by a centrifugal pump to perform material on process; when an anion-exchange resin column underwent material on process, a lactic acid solution treated with the third cation-exchange resin column subunit to have a concentration of 20% and iron ions of <Sppm was pumped into the anion-exchange resin column by a centrifugal pump to perform material on process, when the concentration reached >0.5% at the outlet of the cation-exchange resin column or the anion-exchange resin column during the material on process, a drain valve was switched to a thin acid valve so that the discharged solution was sent to the thin acid tank; when the concentration reached >2.5% at the outlet of ion- exchange resin column, the thin acid valve was closed and switched to a third discharge valve, and the production process was formally performed.
14 51826873-1
The automatic control system was capable of executing start/stop, flow control, real-time
LU505290 display and alarm of current, power, frequency, status and so on of pumps, as well as opening, status and running time of valves, and the like.
The work efficiency was improved, the consumption of water, alkali, acid and steam in production was reduced, and the product yield was elevated.
Example 3
An extraction method for purifying L-lactic acid solution, as shown in Figure 1, comprised the following steps, (1) Production process, comprising a. One-stage ion-exchange: A crude lactic acid solution with a concentration of 20% and a chroma of <300APHA pre-treated by a carbon column was pumped into a cation-exchange resin column subunit and an anion-exchange resin column subunit arranged in series by a centrifugal pump to undergo ion-exchange, in which the flow rate was controlled at 25 m°/h. When the discharged ions reached a chroma < 50 to 100 APHA, it was discharged into a one-stage ion- exchange material tank. One cation-exchange resin column subunit comprised a plurality of cation-exchange resin columns arranged in parallel, and one anion-exchange resin column subunit comprised a plurality of anion-exchange resin columns arranged in parallel. b. Two-stage ion-exchange: It could play a protective role when the discharged material index of the one-stage ion-exchange was unqualified. In the two-stage ion-exchange, two cation- exchange resin column subunits were arranged in series and then arranged in series with two anion- exchange resin column subunits arranged in series. c. Three-stage ion-exchange: It could ensure that the discharged material from ion-exchange was qualified in terms of ions and chroma (iron ions < 2ppm, chloride ions < 2ppm, sulfate radicals < Sppm, chroma < 50 to 100 APHA). In the three-stage ion-exchange, three cation-exchange resin column subunits were arranged in series and then arranged in series with three anion-exchange resin column subunits arranged in series.
The three-stage ion-exchange was adopted in the production process, in which the three-stage ion-exchange specifically comprised the following (as shown in Figure 2): the crude lactic acid solution after decolorization was pumped into a first cation-exchange resin column subunit, a second cation-exchange resin column subunit, and a third cation-exchange resin column subunit by a centrifugal pump at a flow rate of 15 to 30 m°/h, and then discharged into a transfer tank, and then pumped into a first anion-exchange resin column subunit, a second anion-exchange resin 51826873-1 column subunit, and a third anion-exchange resin column subunit by a centrifugal pump at a flow rate of 25 m°/h (wherein, in one example, the first cation-exchange resin column subunit consisted 205290 of 5 cation-exchange resin columns arranged in parallel, and was arranged in series with the second cation-exchange resin column subunit consisting of 5 cation-exchange resin columns arranged in parallel, and then arranged in series with the third cation-exchange resin column subunit consisting of 5 cation-exchange resin columns arranged in parallel; after undergoing ion-exchange in the three cation-exchange resin column subunits, the material entered anion-exchange resin column subunits for ion-exchange, in which the first anion-exchange resin column subunit consisted of 4 anion-exchange resin columns arranged in parallel, and was arranged in series with the second anion-exchange resin column subunit consisting of 4 anion-exchange resin columns arranged in parallel, and then arranged in series with the third anion-exchange resin column subunit consisting of 4 anion-exchange resin columns arranged in parallel), and the columns were controlled by an intelligent control system.
(2) Circulation process: The anion-exchange resin columns selected in the actual production process were OH type D319 macroporous weak basic anion-exchange resin.
This type of resin had larger physical pores, faster exchange speed, large exchange capacity, high regeneration rate, good organic pollution resistance, osmotic pressure resistance, impact change resistance and high physical strength.
In addition to a large amount of lactic acid radicals, there were also small amounts of organic acid radicals such as oxalic acid radicals and gluconic acid radicals, sulfate radicals, chloride ions, amino acids, and negatively charged pigments, etc. in the crude lactic acid solution.
According to the adsorption selection order of weak basic anion-exchange resin for acid radicals, namely, OH>SO4,">lactate radical>NO3;>CI1>F", a large amount of lactate ions would be adsorbed on the anion-exchange resin during the production process, and then the lactate ions adsorbed on the anion-exchange resin would be exchanged by the sulfate ions in the feedstock lactic acid solution, and combined with H in the material to generate lactic acid.
However, in the production process, we judged the failure of ion-exchange resin column by whether there was a chlorine ion outflowing from the outlet of the ion-exchange resin column.
During the process that material passed through the ion-exchange resin column, the resin layer therein could be divided into three layers according to the adsorption capacity of resin (as shown in Figure 3), that was, the first layer was a saturated layer, the second layer was an ion-exchange layer, and the third layer was a protective layer.
When the material was continuously introduced, the adsorption capacity of resin was gradually saturated, the saturated layer moved to the ion-exchange layer, the ion- exchange layer moved to the protective layer (the resin itself did not really move, and this was merely to express more vividly the change of the adsorption capacity of resin), the ion-exchange resin column would lose the protection of the protective layer and there would be leakage of
16 518268731 chloride ions, and it would be judged that the ion-exchange column was invalid, but there were still lactate ions on the ion-exchange layer resin that had not been exchanged.
At this time, the 505290 circulation of the anion-exchange resin column was initiated, until sulfate radicals flowed out from the outlet of the ion-exchange resin column, it could be judged that the ion-exchange resin column was completely invalid, in such way, the yield of the ion-exchange resin column could be improved.
(3) Material off process: Three columns arranged in series were used to push the material in a completely invalid ion-exchange resin column with steam condensation water or hot pure water (having a temperature of 47 °C) into a before-ion-exchange tank or a next spare column.
During the material off process, the concentration change at the outlet of the invalid column should be observed; when the concentration was < 2.5%, the material should be introduced into the thin acid tank; when the concentration was < 0.5%, the material off process was completed.
(4) Backwashing process: The column in which the material off process was completed was backwashed with steam condensation water, and the purpose of which was to loosen the resin layer and remove broken resin particles and some impurities by backwashing.
(5) Regeneration process: Waste acid and waste alkali were used for blending concentrated acid and concentrated alkali, respectively, in which the waste acid and waste alkali discharged during the rinsing process were directly introduced into pipelines of concentrated acid and concentrated alkali and underwent blending in mixers, three columns arranged in series were herein adopted as well, which improved the utilization rates of acid and alkali and reduced the production cost of factory.
Hydrochloric acid with a concentration of 4% was added into cation- exchange resin column, and sodium hydroxide with a concentration of 5.5% was added into anion- exchange resin column.
The acid and alkali added had a volume 1.5 to 2 times that of the resin, and the soaking was performed for 2 to 4 hours.
Since the recovered acid and alkali were used for blending the concentrated acid and concentrated alkali, the consumption of acid and alkali was reduced.
(6) Rinsing process: Three columns arranged in series were adopted as well, the soaked columns were rinsed with hot pure water, and the waste acid and the waste alkali discharged during the rinsing process were reused, in which they were directly introduced into an inlet of a regeneration column and used by blending with the concentrated acid and the concentrated alkali, respectively.
The rinsing process was divided into two steps.
In the first step, the waste acid or the waste alkali in the column was rinsed out until the cation-exchange resin column was rinsed to have a pH of 3 to 4, or the anion-exchange resin column was rinsed to have a pH of 8 to 9, then the second step was performed.
In the second step, the water discharged during the rinsing process was directly introduced into a column for the backwashing process, and this step was also performed to make full use of water, thereby reducing the amount of water used and production
17 518268731 costs. After the rinsing process was completed, the cation-exchange resin column and anion-
LU505290 exchange resin column could not be used in the production process until the detection showed iron ions < 2ppm and chloride ions < 2ppm. The water consumption was about 4 to 8 times the volume of the resin. (7) Pre-saturation process: The water in the rinsed column was replaced with a thin acid solution (having a concentration of < 2.5%), which reduced the burden of concentration process, thereby reducing production costs. (8) Material on process: When a cation-exchange resin column underwent material on process, a crude lactic acid solution pre-treated with a carbon column to have a concentration of 17-22% and a chroma of <300 APHA was pumped into the cation-exchange resin column by a centrifugal pump to perform material on process; when an anion-exchange resin column underwent material on process, a lactic acid solution treated with the third cation-exchange resin column subunit to have a concentration of 20% and iron ions of <Sppm was pumped into the anion-exchange resin column by a centrifugal pump to perform material on process, when the concentration reached >0.5% at the outlet of the cation-exchange resin column or the anion-exchange resin column during the material on process, a drain valve was switched to a thin acid valve so that the discharged solution was sent to the thin acid tank; when the concentration reached >2.5% at the outlet of ion- exchange resin column, the thin acid valve was closed and switched to a third discharge valve, and the production process was formally performed.
The automatic control system was capable of executing start/stop, flow control, real-time display and alarm of current, power, frequency, status and so on of pumps, as well as opening, status and running time of valves, and the like.
The work efficiency was improved, the consumption of water, alkali, acid and steam in production was reduced, and the product yield was elevated.
Comparative Example 1
The extraction method of L-lactic acid solution,
M-production process, comprised:
One-stage ion-exchange: À crude lactic acid solution with a concentration of 22 % and a chroma of <300APHA pre-treated by a carbon column was pumped into a cation-exchange resin column subunit and an anion-exchange resin column subunit arranged in series by a centrifugal pump to undergo ion-exchange, in which the flow rate was controlled at 15 m°/h. When the discharged material ions reached a chroma < 50 to 100 APHA, it was discharged to obtain the L- 18 51826873-1 lactic acid solution of Comparative Example 1. One cation-exchange resin column subunit
LU505290 comprised 15 cation-exchange resin columns arranged in parallel, and one anion-exchange resin column subunit comprised 12 anion-exchange resin columns arranged in parallel.
Table 1: Comparison table of product indicators after L-lactic acid purification
Comparative Example 1 | Example 1 Example 2 Example 3
Chloride ion (%) < 0.0003 0.0002 0.0002 0.0002
Sulfate radical (%) < 0.0005 0.0003 0.0003 0.0003
Iron ion (%) < 0.0002 0.0001 0.0001 0.0001
In Comparative Example 1, 15 cation-exchange resin columns arranged in parallel and 12 anion-exchange resin columns arranged in parallel were adopted. Compared with the three-stage ion-exchange, the amount of material passing was small, the discharge was prone to being unqualified, the chroma of the discharged material was high, the columns were switched frequently, the yield of lactic acid was low, the consumption of regenerated acid and alkali was high, and a lot of water was consumed.
The three-stage ion-exchange is 5 or more cation-exchange resin columns with parallel, in series with 5 or more cation-exchange resin columns with parallel, then in series with 5 or more cation-exchange resin columns with parallel, and 4 or more anion-exchange resin columns with parallel, in series with 4 or more anion-exchange resin columns with parallel, and then in series with 4 or more anion-exchange resin columns with parallel.so that the columns are switched less frequently, the yield of lactic acid is high, the consumption of regenerated acid and alkali is low, the water consumption is small, the amount of material passing is great, the qualification rate of the discharged material could be effectively guaranteed, and the chroma of the discharged material is low.
The above description of the disclosed examples is provided to enable any person skilled in the art to implement or use the present invention. Various modifications to these examples will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other examples without departing from the spirit or scope of the present invention. 19 51826873-1
Therefore, the present invention will not be limited to the examples shown herein, but is to be in
LU505290 according to the widest scope consistent with the principles and novel features disclosed herein. 51826873-1
Claims (8)
1. A method for purifying L-lactic acid, comprising the following steps: (1) Production process: feeding a crude lactic acid solution into a cation-exchange resin column unit and an anion-exchange resin column unit arranged in series to obtain a purified lactic acid solution; the cation-exchange resin column unit comprises three stages of cation-exchange resin column subunits arranged in series, and each stage of cation-exchange resin column subunit comprises at least two cation-exchange resin columns arranged in parallel; the anion-exchange resin column unit comprises three stages of anion-exchange resin column subunits arranged in series, and each stage of anion-exchange resin column subunit comprises at least two anion- exchange resin columns arranged in parallel; the anion-exchange resin column is OH’ type D319 macroporous weak basic anion-exchange resin; (2) Circulation process: feeding the crude lactic acid solution into an anion-exchange resin column switched from the production process, and circulating the effluent in the anion-exchange resin column until a sulfate ion is detected in the effluent, and the circulation process ends; (3) Material off process: carrying out material off process in a cation-exchange resin column switched from the production process and an anion-exchange resin column switched from the circulation process respectively by using water, and recovering the replaced material, (4) Backwashing process: carrying out backwashing of a cation-exchange resin column and an anion-exchange resin column switched from the material off process by using water; (5) Regeneration process: regenerating a cation-exchange resin column and an anion- exchange resin column switched from the backwashing process by using regeneration solutions, in which the regeneration solution for the cation-exchange resin column is a diluted acid aqueous solution, and the regeneration solution for the anion-exchange resin column is a diluted alkali aqueous solution; (6) Rinsing process: rinsing an anion-exchange resin column and a cation-exchange resin column switched from the regeneration process by using water; (7) Pre-saturation process: by using a thin acid solution, replacing the water in an anion- exchange resin column and a cation-exchange resin column that have been rinsed; (8) Material on process: by using the crude lactic acid solution, carrying out material on process in a cation-exchange resin column after the pre-saturation process, and by using an effluent of the cation-exchange resin column unit in the production process, carrying out material on process in an anion-exchange resin column; 21 518268731
Wherein, the cation-exchange resin columns and the anion-exchange resin columns in the
. . . . . . LU505290 production process, circulation process, material off process, backwashing process, regeneration process, rinsing process, pre-saturation process and material on process are switched continuously.
2. The method for purifying L-lactic acid according to claim 1, wherein the production process has a crude lactic acid solution with a mass concentration of 17% to 22% and a chroma of <300 APHA as feedstock.
3. The method for purifying L-lactic acid according to claim 1, wherein the production process has a feed flow that is controlled at 15 to 30 m°/h.
4. The method for purifying L-lactic acid according to claim 1, wherein the material off process uses steam condensation water or hot pure water, and the water has a temperature of 45 to
°C.
5. The method for purifying L-lactic acid according to claim 1, wherein the material off process is completed when the material off process has a discharged material solution with a lactic acid mass concentration of <0.5%.
6. The method for purifying L-lactic acid according to claim 1, wherein the diluted acid aqueous solution is a diluted hydrochloric acid solution, and the diluted hydrochloric acid solution has a mass percent concentration of 3.5 to 5%; the diluted alkaline aqueous solution is a sodium hydroxide solution, and the sodium hydroxide solution has a mass percent concentration of 5 to
6%.
7. The method for purifying L-lactic acid according to claim 1, wherein the regeneration solution added in the regeneration process is 1.5 to 2 times the volume of resin, and the resin is soaked for 2 to 4 hours.
8. The method for purifying L-lactic acid according to claim 1, wherein during the rinsing process, the rinsing process for the cation-exchange resin column is completed when having an 22 518268731 effluent with a pH value of 3 to 4, and the rinsing process for the anion-exchange resin column is LU505290 completed when having a pH value of 8 to 9. 23 51826873-1
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| CN202210140354.0A CN114409530A (en) | 2022-02-16 | 2022-02-16 | Purification method of L-lactic acid |
| CN202210525607.6A CN114605257B (en) | 2022-02-16 | 2022-05-16 | Purification method of L-lactic acid |
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| CN114409530A (en) * | 2022-02-16 | 2022-04-29 | 欧尚元(天津)有限公司 | Purification method of L-lactic acid |
| CN115354152B (en) * | 2022-08-25 | 2023-12-29 | 上海锦源晟新能源材料有限公司 | Continuous operation system and method for separating and enriching cobalt from high-impurity cobalt-containing solution |
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| CN100401916C (en) * | 2006-03-15 | 2008-07-16 | 浙江大学 | Decoloring method for heliangine lixiviation liquid |
| CN104817449B (en) * | 2014-12-31 | 2016-09-07 | 三达膜科技（厦门）有限公司 | A kind of process for separation and purification of succinic acid |
| CN110483276A (en) * | 2019-07-26 | 2019-11-22 | 山东寿光巨能金玉米开发有限公司 | A kind of D-ALPHA-Hydroxypropionic acid extracting method |
| CN111269107B (en) * | 2020-04-09 | 2021-08-03 | 安徽固德生物工程有限公司 | L-lactic acid purification and refining method |
| CN111592458B (en) * | 2020-05-25 | 2022-12-23 | 中粮营养健康研究院有限公司 | Method for separating lactic acid |
| CN113527085A (en) * | 2021-07-23 | 2021-10-22 | 厦门世达膜工程有限公司 | Production method for purifying lactic acid from lactic acid fermentation liquor |
| CN114409530A (en) * | 2022-02-16 | 2022-04-29 | 欧尚元(天津)有限公司 | Purification method of L-lactic acid |
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| LU505290B1 (en) | 2024-02-19 |
| WO2023155797A1 (en) | 2023-08-24 |
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