CN114748884B - Lactic acid ester reaction rectification apparatus for producing - Google Patents
Lactic acid ester reaction rectification apparatus for producing Download PDFInfo
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- CN114748884B CN114748884B CN202210490884.8A CN202210490884A CN114748884B CN 114748884 B CN114748884 B CN 114748884B CN 202210490884 A CN202210490884 A CN 202210490884A CN 114748884 B CN114748884 B CN 114748884B
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 98
- 150000003903 lactic acid esters Chemical class 0.000 title claims description 13
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims abstract description 302
- JVTAAEKCZFNVCJ-UHFFFAOYSA-M Lactate Chemical compound CC(O)C([O-])=O JVTAAEKCZFNVCJ-UHFFFAOYSA-M 0.000 claims abstract description 168
- 239000004310 lactic acid Substances 0.000 claims abstract description 151
- 235000014655 lactic acid Nutrition 0.000 claims abstract description 151
- 238000005886 esterification reaction Methods 0.000 claims abstract description 124
- 230000032050 esterification Effects 0.000 claims abstract description 120
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 107
- 230000018044 dehydration Effects 0.000 claims abstract description 106
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 44
- 229920000747 poly(lactic acid) Polymers 0.000 claims abstract description 37
- 239000004626 polylactic acid Substances 0.000 claims abstract description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 17
- 238000004519 manufacturing process Methods 0.000 claims abstract description 17
- 239000003054 catalyst Substances 0.000 claims description 32
- 239000000047 product Substances 0.000 claims description 31
- 238000012856 packing Methods 0.000 claims description 18
- 238000010992 reflux Methods 0.000 claims description 18
- 230000003197 catalytic effect Effects 0.000 claims description 16
- 239000000945 filler Substances 0.000 claims description 12
- 239000002253 acid Substances 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 7
- 239000002994 raw material Substances 0.000 claims description 7
- 239000011949 solid catalyst Substances 0.000 claims description 7
- 239000011347 resin Substances 0.000 claims description 5
- 229920005989 resin Polymers 0.000 claims description 5
- 238000000605 extraction Methods 0.000 claims description 4
- 238000011049 filling Methods 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 239000000376 reactant Substances 0.000 claims description 4
- 238000004821 distillation Methods 0.000 claims description 3
- 238000000066 reactive distillation Methods 0.000 claims 8
- 238000006116 polymerization reaction Methods 0.000 claims 2
- 239000007795 chemical reaction product Substances 0.000 claims 1
- 238000003809 water extraction Methods 0.000 claims 1
- 238000005265 energy consumption Methods 0.000 abstract description 3
- 208000005156 Dehydration Diseases 0.000 description 87
- 238000000034 method Methods 0.000 description 24
- LZCLXQDLBQLTDK-UHFFFAOYSA-N ethyl 2-hydroxypropanoate Chemical compound CCOC(=O)C(C)O LZCLXQDLBQLTDK-UHFFFAOYSA-N 0.000 description 20
- 239000012043 crude product Substances 0.000 description 11
- 229940116333 ethyl lactate Drugs 0.000 description 10
- 238000011068 loading method Methods 0.000 description 10
- 239000007791 liquid phase Substances 0.000 description 9
- 239000012071 phase Substances 0.000 description 8
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 7
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 238000006136 alcoholysis reaction Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000006555 catalytic reaction Methods 0.000 description 3
- JJTUDXZGHPGLLC-UHFFFAOYSA-N lactide Chemical compound CC1OC(=O)C(C)OC1=O JJTUDXZGHPGLLC-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 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 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- -1 carbon alcohols Chemical class 0.000 description 2
- 239000003729 cation exchange resin Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 238000005373 pervaporation Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 description 2
- UUFQTNFCRMXOAE-UHFFFAOYSA-N 1-methylmethylene Chemical group C[CH] UUFQTNFCRMXOAE-UHFFFAOYSA-N 0.000 description 1
- LPEKGGXMPWTOCB-UHFFFAOYSA-N 8beta-(2,3-epoxy-2-methylbutyryloxy)-14-acetoxytithifolin Natural products COC(=O)C(C)O LPEKGGXMPWTOCB-UHFFFAOYSA-N 0.000 description 1
- 206010007269 Carcinogenicity Diseases 0.000 description 1
- 239000003377 acid catalyst Substances 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000007670 carcinogenicity Effects 0.000 description 1
- 231100000260 carcinogenicity Toxicity 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 239000012295 chemical reaction liquid Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- ODQWQRRAPPTVAG-GZTJUZNOSA-N doxepin Chemical compound C1OC2=CC=CC=C2C(=C/CCN(C)C)/C2=CC=CC=C21 ODQWQRRAPPTVAG-GZTJUZNOSA-N 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910001507 metal halide Inorganic materials 0.000 description 1
- 150000005309 metal halides Chemical class 0.000 description 1
- 229940057867 methyl lactate Drugs 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- ILVGAIQLOCKNQA-UHFFFAOYSA-N propyl 2-hydroxypropanoate Chemical compound CCCOC(=O)C(C)O ILVGAIQLOCKNQA-UHFFFAOYSA-N 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/26—Fractionating columns in which vapour and liquid flow past each other, or in which the fluid is sprayed into the vapour, or in which a two-phase mixture is passed in one direction
- B01D3/28—Fractionating columns with surface contact and vertical guides, e.g. film action
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
- B01D3/324—Tray constructions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0053—Details of the reactor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/24—Stationary reactors without moving elements inside
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a reaction rectification production device of lactate, which mainly comprises a lactate esterification tower and a lactate dehydration tower; the low-carbon alcohol feeding port is arranged at the bottom of the reaction section of the lactic acid esterification tower, the lactic acid feeding port is arranged at the upper part of the reaction section of the lactic acid dehydration tower, the circulating polylactic acid feeding port is arranged at the top of the reaction section of the lactic acid esterification tower, the top of the lactic acid dehydration tower is provided with a water collecting pipeline, and the bottom of the lactic acid dehydration tower is provided with a circulating polylactic acid collecting pipeline; the high-purity lactate product is obtained at the top of the lactate esterification tower, excessive lactic acid and polylactic acid obtained at the bottom of the lactate esterification tower enter a lactate dehydration tower, product water is extracted at the top of the lactate dehydration tower, and the polylactic acid obtained at the bottom of the lactate dehydration tower returns to the lactate esterification tower. After passing through the two reaction rectifying devices, the polylactic acid and the low-carbon alcohol have the mass fraction of the lactate product reaching more than 98.5 percent, the product yield reaching more than 99 percent, and the energy consumption is greatly reduced.
Description
Technical Field
The invention relates to the technical field of synthesis of chemical lactate in the chemical field, in particular to a high-efficiency energy-saving lactate reaction rectification production device, which is a device for producing lactate by utilizing a reaction rectification technology after dehydration treatment of lactic acid raw materials.
Background
Organic solvents such as benzene, carbon tetrachloride and chloroform commonly used in the traditional process have certain toxicity and carcinogenicity, and due to the increasingly strict environmental protection requirements in recent years, the search for safe, green and efficient alternative solvents becomes an urgent requirement for chemical production. Among them, the lactate products such as ethyl lactate have the advantages of biodegradability, innocuity, economy, safety, etc., and are one of the most promising green solvents.
The product structure of the lactate is CH3CH (OH) COO-R, wherein R comprises but is not limited to low carbon alcohols such as methanol, ethanol, n-propanol, isopropanol and the like. Is miscible with water and is miscible with organic solvents such as alcohols, aromatic hydrocarbons, esters, hydrocarbons, oils, etc., and is usually obtained by esterification of lactic acid and lower alcohols under the catalysis of strong acid.
The main raw materials for synthesizing the lactate are lactic acid and low-carbon alcohols, most of the traditional synthesis processes adopt a kettle-type reactor under the vacuum condition, concentrated sulfuric acid is used as a catalyst, benzene or toluene is also required to be added as a water-carrying agent, and the problems of complex flow, more byproducts, low product purity, serious equipment corrosion and the like exist. In recent years, scientific researchers at home and abroad have developed a series of solid catalysts for esterification reaction, such as metal halides, rare earth compounds, strong acid ion resins and the like, and the novel solid catalysts overcome the defects of the liquid-phase strong acid catalysts to a certain extent, and simultaneously promote the feasibility of the catalytic rectification technology in the lactate synthesis production process. The packing mode of the solid catalyst is a key technical problem affecting the efficiency of the catalyst, and the catalytic distillation structured packing is an efficient packing mode of the catalyst.
The patent CN 112552168A utilizes lactide and ethanol to react under the catalysis of strong acid cation exchange resin to generate ethyl lactate, an azeotrope of ethyl lactate and water is obtained at the top of a catalytic rectifying tower, after phase separation, the obtained crude ester is further separated, an ethyl lactate product is extracted at the bottom of the rectifying tower, and the top material is recycled to the catalytic rectifying tower. In the process, water and ethyl lactate are mainly used in the top of the refining tower, and the recycling of the ethyl lactate to the catalytic rectifying tower is unfavorable for the reaction of lactide and ethanol, so that the conversion rate of raw materials lactide and ethanol is reduced.
The patent CN 109438228A utilizes lactic acid and ethanol to carry out esterification reaction under the catalysis of concentrated sulfuric acid by stirring, heating and pressurizing, the mixed steam of ethanol, water and a small amount of ethyl lactate output by the esterification reaction is fractionated by a fractionating tower, the ethanol and the water mixed steam are input into a pervaporation membrane for water separation, the separated ethanol steam is output from the pervaporation membrane, after being pressurized, the ethanol steam is added into an esterification reaction liquid for continuous participation reaction, the obtained esterification liquid after the reaction is cooled, and excessive ethanol is distilled at normal pressure for recycling; ethyl lactate was distilled off under reduced pressure. The method is an intermittent production flow, the flow is complex, the operation is complex, the used catalyst is concentrated sulfuric acid, and more side reactions exist.
In summary, the existing production process of lactate products generally has the problems of low product yield, complex process, low product concentration and the like.
Disclosure of Invention
According to the defects of the prior art, the invention provides a reaction rectification production device for lactate, and the method for producing lactate has the advantages of simple flow, high product yield, high lactate purity and the like.
The invention relates to a high-efficiency energy-saving lactate reaction rectification production device which mainly comprises a lactate esterification tower and a lactate dehydration tower. The lactic acid esterification tower is used for producing lactate products, and the lactic acid dehydration tower is used for preparing polylactic acid through lactic acid dehydration; the low-carbon alcohol feeding port is arranged at the bottom of the reaction section of the lactic acid esterification tower, the lactic acid feeding port is arranged at the upper part of the reaction section of the lactic acid dehydration tower, the circulating polylactic acid feeding port is arranged at the top of the reaction section of the lactic acid esterification tower, the top of the lactic acid dehydration tower is provided with a water collecting pipeline, and the bottom of the lactic acid dehydration tower is provided with a circulating polylactic acid collecting pipeline; the high-purity lactate product is obtained at the top of the lactate esterification tower, excessive lactic acid and polylactic acid obtained at the bottom of the lactate esterification tower enter a lactate dehydration tower, product water is extracted at the top of the lactate dehydration tower, and the polylactic acid obtained at the bottom of the lactate dehydration tower returns to the lactate esterification tower.
The technical scheme of the invention is as follows:
A reaction rectification production device of lactate mainly comprises a lactate esterification tower and a lactate dehydration tower; the low-carbon alcohol feeding port is arranged at the bottom of the reaction section of the lactic acid esterification tower, the lactic acid feeding port is arranged at the upper part of the reaction section of the lactic acid dehydration tower, the circulating polylactic acid feeding port is arranged at the top of the reaction section of the lactic acid esterification tower, the top of the lactic acid dehydration tower is provided with a water collecting pipeline, and the bottom of the lactic acid dehydration tower is provided with a circulating polylactic acid collecting pipeline; the high-purity lactate product is obtained at the top of the lactate esterification tower, excessive lactic acid and polylactic acid obtained at the bottom of the lactate esterification tower enter a lactate dehydration tower, product water is extracted at the top of the lactate dehydration tower, and the polylactic acid obtained at the bottom of the lactate dehydration tower returns to the lactate esterification tower.
In the reaction rectification production device of the lactate, the rectifying section of the lactate esterification tower and the internal parts of the stripping section of the lactate esterification tower are filler or trays; the internal components of the reaction section of the lactic acid esterification tower are strapping packing, modularized catalytic rectification structured packing, lactic acid esterification tower trays and the like; the rectifying section of the lactic acid dehydration tower and the rectifying section of the lactic acid dehydration tower are filled with packing or trays, and the inner parts of the reaction section of the lactic acid dehydration tower are packed with packing, modularized catalytic rectification structured packing or lactic acid dehydration trays.
The number of the trays of the lactic acid esterification tower is 20-50, wherein the number of the trays of the rectifying section is 5-15, the number of the trays of the reaction section is 10-40, and the number of the trays of the stripping section is 2-15.
The number of the trays of the lactic acid dehydration tower is 20-50, wherein the number of the trays of the rectifying section is 5-15, the number of the trays of the reaction section is 10-40, and the number of the trays of the stripping section is 2-15.
The operation pressure of the lactic acid esterification tower is 0.02-0.5 atm, and the reflux ratio is 0.1-1.3; the temperature of the tower top is 45-70 ℃, the temperature of the tower bottom is 100-126 ℃, and the temperature of the reaction section is 70-110 ℃.
The residence time of the reaction materials in each theoretical stage of the reaction section of the lactic acid esterification tower is 20-100 seconds, the reaction section is filled with solid catalysts such as macroporous strong acid resin particles and the like, and the catalyst filling amount is 0.2-0.6 m 3 catalyst/m 3 reaction section.
The operation pressure of the lactic acid dehydration tower is 0.02-0.5 atm, and the reflux ratio is 0.5-4; the temperature of the tower top is 45-90 ℃, the temperature of the tower bottom is 125-140 ℃, and the temperature of the reaction section is 70-120 ℃.
The residence time of the reaction materials in each theoretical stage of the lactic acid dehydration tower reaction section is 20-100 seconds, the reaction section is filled with solid catalysts such as macroporous strong acid resin particles and the like, and the catalyst filling amount is 0.2-0.6 m 3 catalyst/m 3 reaction section.
The feeding mole ratio of the raw material low-carbon alcohol to the lactic acid is 1:1.3-1:8. The molar ratio of the reactant lower alcohol to lactic acid in the reaction section of the lactic acid esterification tower is always less than 0.5.
The invention simplifies the process flow and greatly reduces the energy consumption of production, and is characterized in that the invention adopts the combined process of two reaction rectifying towers, optimizes the reaction sequence, realizes the high integration of the process through the design and transformation of equipment, adopts strong acid type cation exchange resin as a catalyst, and adopts the form of catalytic rectifying structured packing to be filled in a reaction section, thereby improving the catalyst efficiency. The invention improves the conversion rate of lactic acid esterification by pre-dehydrating raw material lactic acid, thereby improving the purity of the product extracted from the top of the lactic acid esterification tower; and the subsequent separation process is not needed, and the energy-saving requirement is further met.
The invention provides a lactate reaction rectification production device which mainly comprises a lactate esterification tower and a lactate dehydration tower, wherein the lactate esterification tower is used for producing lactate products, and the lactate dehydration tower is used for preparing polylactic acid through lactate dehydration; circulating polylactic acid and low-carbon alcohol enter a reaction rectifying area from the top and the bottom of a reaction section of a lactic acid esterification tower respectively, and products of lactic acid and lactate are removed from the reaction area of the lactic acid esterification tower while alcoholysis reaction is carried out in the reaction rectifying area of the lactic acid esterification tower, so that reactants of low-carbon alcohol is completely converted; feeding fresh lactic acid raw material, excessive lactic acid and polylactic acid extracted from the kettle of a lactic acid esterification tower into a lactic acid dehydration tower, and carrying out lactic acid dehydration reaction in the lactic acid dehydration tower to obtain polylactic acid from the kettle of the lactic acid dehydration tower; the polylactic acid is circulated to a lactic acid esterification tower, and is fed from the upper part of a reaction section of the lactic acid esterification tower, so that the molar ratio of the polylactic acid to the low-carbon ester in the reaction section of the tower is ensured to be at a higher value; finally, the complete conversion of the low-carbon alcohol is realized, and the high-purity lactate product can be obtained at the top of the lactate esterification tower.
The invention provides a high-efficiency energy-saving reaction rectifying technology device for producing lactate, wherein after polylactic acid and low-carbon alcohol pass through two reaction rectifying devices, high-purity lactate products can be obtained at the top of a lactate esterification tower, and the polylactic acid is extracted from the bottom of a lactate dehydration tower and circulated to a reaction rectifying unit. The invention has the advantages that the mass fraction of the lactate product can reach more than 98.5%, the product yield can reach more than 99%, and the energy consumption is also greatly reduced.
Drawings
FIG. 1 is a schematic diagram of a reaction distillation production device for lactate
1A lactic acid esterification tower; 2a lactic acid dehydration tower; 3, rectifying section of lactic acid esterification tower; 4, a reaction section of a lactic acid esterification tower; 5 stripping section of lactic acid esterification tower; 6a rectifying section of the lactic acid dehydration tower; 7, a reaction section of a lactic acid dehydration tower; 8 stripping section of lactic acid dehydration tower; 9 lactate condenser at top of the lactate esterification tower; 10a reboiler for a crude product at the bottom of the lactic acid esterification tower; 11 a lactic acid dehydration tower top water condenser; 12 a lactic acid reboiler at the bottom of the lactic acid dehydration tower; 13 lower alcohol feed line; 14 polylactic acid feed line; 15a crude product at the bottom of the lactic acid esterification tower; returning the liquid phase crude product from the lactic acid esterification tower to the tower; 17 a gas phase crude product returned from the lactic acid esterification tower; 18a raw product line; 19 gas phase lactic acid esters; 20 liquid phase lactic acid esters; 21 refluxing lactate esters; 22 lactate products; 23 lactic acid feed line; 24 polylactic acid at the bottom of the lactic acid dehydration tower; returning the 25 lactic acid dehydration tower to the tower liquid phase polylactic acid; 26 lactic acid dehydration column reflux gas phase lactate; 27 gas phase water; 28 liquid phase water; 29 backwater; 30, water was distilled off.
Detailed Description
The invention will be further described with reference to examples of application and the description, but the scope of the invention is not limited thereto.
The device is shown in figure 1, and the lactic acid esterification tower (1) consists of a lactic acid esterification tower rectifying section (3), a lactic acid esterification tower reaction section (4) and a lactic acid esterification tower stripping section (5); the lactic acid dehydration tower (2) consists of a lactic acid dehydration tower rectifying section (6), a lactic acid dehydration tower reaction section (7) and a lactic acid dehydration tower stripping section (8); the two-tower device comprises a lactic acid esterification tower (1), a lactic acid dehydration tower (2), a lactic acid ester condenser (9) at the top of the lactic acid esterification tower, a water condenser (11) at the top of the lactic acid dehydration tower, a crude product reboiler (10) at the bottom of the lactic acid esterification tower, a lactic acid reboiler (12) at the bottom of the lactic acid dehydration tower, related feed pipelines and pipelines connected with the above devices; the feeding pipeline of the polylactic acid (14) is connected to the top of the reaction section (4) of the lactic acid esterification tower, the feeding pipeline of the low-carbon alcohol (13) is connected to the bottom of the reaction section (4) of the lactic acid esterification tower, the gas-phase lactate (19) at the top of the lactic acid esterification tower (1) is connected with the gas-phase inlet of the lactate condenser (9) at the top of the lactic acid esterification tower through a pipeline, the condensed liquid-phase lactate (20) material extraction pipeline is connected with the liquid-phase outlet of the lactate condenser (9) at the top of the lactic acid esterification tower, meanwhile, one part of reflux lactate (21) at the liquid-phase outlet of the lactate condenser (8) at the top of the lactic acid esterification tower is connected with the top of the lactic acid esterification tower (1) through a pipeline, and the other part of distilled lactate (22) is extracted as a product; the tower kettle of the lactic acid esterification tower (1) is connected with the inlet of the lactic acid dehydration tower (2) through a crude product extraction (18) pipeline, a lactic acid feeding pipeline (23) is connected to the upper part of a lactic acid dehydration tower reaction section (7), steam at the top of the lactic acid dehydration tower (2) is connected with the gas phase inlet of a lactic acid dehydration tower top water condenser (11) through a gas phase water (27) pipeline, one part of reflux water (28) after condensation flows back to the top of the lactic acid dehydration tower (2), the other part of water (30) is extracted from the top of the tower as a light component, and one part of circulating polylactic acid (14) material extraction of the liquid phase product of the tower kettle of the lactic acid dehydration tower (2) returns to the top of the lactic acid esterification tower reaction section (4).
The internal components of the rectifying section (3) and the stripping section (5) of the lactic acid esterification tower can be filler or tray, and the internal components of the reaction section (4) of the lactic acid esterification tower are strapping filler, modularized catalytic rectification structured filler or lactic acid esterification tray and the like; the internal parts of the rectifying section (6) and the stripping section (8) of the lactic acid dehydrating tower are filler or trays, and the internal parts of the reaction section (7) of the lactic acid dehydrating tower are strapping filler, modularized catalytic rectification structured filler or lactic acid dehydrating trays and the like.
Example 1
The process for preparing the lactate by the alcoholysis of the polylactic acid is the same as the process, and comprises a lactate esterification tower, a lactate dehydration tower, a lactate condenser at the top of the lactate esterification tower, a water condenser at the top of the lactate dehydration tower, a crude product reboiler at the bottom of the lactate esterification tower and a lactate reboiler at the bottom of the lactate dehydration tower, wherein the operation pressure of the lactate esterification tower is 0.02atm, the reflux ratio is 0.3, the ethanol feeding amount is 1kmol/h, the rectifying section of the lactate esterification tower and the stripping section of the lactate esterification tower are filled, the inner parts of the rectifying section of the lactate esterification tower are packed, the catalyst loading amount is 0.3m 3 catalyst/m 3, the operation pressure of the lactate dehydration tower is 0.08atm, the reflux ratio is 0.8, the lactic acid feeding amount is 2.0kmol/h, the inner parts of the rectifying section of the lactate dehydration tower and the stripping section of the lactate dehydration tower are filled, the inner parts of the rectifying section of the lactate dehydration tower are packed, and the catalyst loading amount is 0.3m 3/m 3.
After the above process, the purity of the main product ethyl lactate can reach 99.5%, and the yield can reach 99.2%.
Example 2
The method is used for the process of preparing the lactate by the alcoholysis of the polylactic acid, and has the same flow as the flow, and comprises a lactate esterification tower, a lactate dehydration tower, a lactate condenser at the top of the lactate esterification tower, a water condenser at the top of the lactate dehydration tower, a crude product reboiler at the bottom of the lactate esterification tower and a lactate reboiler at the bottom of the lactate dehydration tower, wherein the operation pressure of the lactate esterification tower is 0.04atm, the reflux ratio is 0.5, the methanol feeding amount is 1kmol/h, the rectifying section of the lactate esterification tower and the stripping section of the lactate esterification tower are both filled, the internal part of the rectifying section of the lactate esterification tower is modularized catalytic rectifying structured filler, the catalyst loading amount is 0.2m 3 catalyst/m 3 reaction section, the operation pressure of the lactate dehydration tower is 0.04atm, the reflux ratio is 2, the lactic acid feeding amount is 1.3kmol/h, the internal parts of the rectifying section of the lactate dehydration tower and the stripping section of the lactate dehydration tower are filled, the internal part of the rectifying section of the lactate dehydration tower is modularized rectifying structured filler, and the catalyst loading amount is 0.3m 3 catalyst/m 3 reaction section.
After the above process, the purity of the main product methyl lactate can reach 99.0%, and the yield can reach 99.0%.
Example 3
The method is used for the process of preparing the lactate by the alcoholysis of the polylactic acid, and has the same flow as the flow, and comprises a lactate esterification tower, a lactate dehydration tower, a lactate condenser at the top of the lactate esterification tower, a water condenser at the top of the lactate dehydration tower, a crude product reboiler at the bottom of the lactate esterification tower and a lactate reboiler at the bottom of the lactate dehydration tower, wherein the operation pressure of the lactate esterification tower is 0.02atm, the reflux ratio is 1.1, the feeding amount of isopropanol is 1kmol/h, the internal parts of the rectification section and the stripping section of the lactate esterification tower are trays, the internal parts of the reaction section of the lactate esterification tower are modularized catalytic rectification packing, the catalyst loading amount of the lactate esterification tray and the like is 0.6m 3 catalyst/m 3 reaction section, the operation pressure of the lactate dehydration tower is 0.1atm, the reflux ratio is 3, the feeding amount of the lactic acid is 4.0kmol/h, the internal parts of the rectification section and the stripping section of the lactate dehydration tower are trays, the internal parts of the reaction section of the lactate dehydration tower are bundling trays, the reaction section and the catalyst loading amount of the modularized catalytic packing is 35.3779 m 35.
After the above process, the purity of the main product lactic acid isopropyl alcohol can reach 99.6%, and the yield can reach 99.4%.
Example 4
The method is used for the process of preparing the lactate by the alcoholysis of the polylactic acid, and has the same flow as the flow, and comprises a lactate esterification tower, a lactate dehydration tower, a lactate condenser at the top of the lactate esterification tower, a water condenser at the top of the lactate dehydration tower, a crude product reboiler at the bottom of the lactate esterification tower and a lactate reboiler at the bottom of the lactate dehydration tower, wherein the operation pressure of the lactate esterification tower is 0.1atm, the reflux ratio is 1.3, the ethanol feeding amount is 1kmol/h, the rectifying section of the lactate esterification tower and the stripping section of the lactate esterification tower are trays, the internal components of the reaction section of the lactate esterification tower are modularized catalytic rectification structured packing, the catalyst loading amount is 0.3m 3 catalyst/m 3 reaction section, the operation pressure of the lactate dehydration tower is 0.05atm, the reflux ratio is 4, the lactic acid feeding amount is 5.0kmol/h, the internal components of the rectifying section of the lactate dehydration tower and the stripping section of the lactate dehydration tower are packing, the internal components of the reaction section of the lactate dehydration tower are trays, and the catalyst loading amount is 0.3m 3 catalyst/m 3 reaction section.
After the above process, the purity of the main product ethyl lactate can reach 99.1%, and the yield can reach 99.2%.
Example 5
The method is used for the process of preparing the lactate by the alcoholysis of the polylactic acid, and has the same flow as the flow, and comprises a lactate esterification tower, a lactate dehydration tower, a lactate condenser at the top of the lactate esterification tower, a water condenser at the top of the lactate dehydration tower, a crude product reboiler at the bottom of the lactate esterification tower and a lactate reboiler at the bottom of the lactate dehydration tower, wherein the operation pressure of the lactate esterification tower is 0.01atm, the reflux ratio is 0.7, the feeding amount of n-propanol is 1kmol/h, the rectifying section of the lactate esterification tower and the stripping section of the lactate esterification tower are both filled, the inner part of the rectifying section of the lactate esterification tower is a strapping filler, the loading amount of the catalyst is 0.5m 3 catalyst/m 3 reaction section, the operation pressure of the lactate dehydration tower is 0.08atm, the reflux ratio is 1.5, the feeding amount of the lactic acid is 6.0kmol/h, the inner parts of the rectifying section of the lactate dehydration tower and the stripping section of the lactate dehydration tower are trays, the inner part of the rectifying section of the lactate dehydration tower is strapping filler, and the loading amount of the catalyst is 0.6.6 m 3 catalyst/m 3 reaction section.
After the above process, the purity of the main product propyl lactate can reach 99.6%, and the yield can reach 99.3%.
The technical scheme disclosed and proposed by the invention can be realized by a person skilled in the art by appropriately changing the condition route and other links in consideration of the content of the present invention, although the method and the preparation technology of the invention have been described by the preferred embodiment examples, the related person can obviously modify or recombine the method and the technical route described herein to realize the final preparation technology without departing from the content, spirit and scope of the invention. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be included within the spirit, scope and content of the invention. The invention belongs to the known technology.
Claims (9)
1. The utility model provides a reaction rectification apparatus for producing of lactate, characterized by, mainly by two reaction rectification towers of lactate esterification tower and lactate dehydration tower constitute; wherein the lactic acid esterification tower mainly generates the reaction of polylactic acid and low-carbon alcohol to generate lactic acid ester, and the lactic acid dehydration tower mainly generates the reaction of lactic acid polymerization to generate polylactic acid; the low-carbon alcohol feed inlet is arranged at the bottom of the reaction section of the lactic acid esterification tower, the circulating polylactic acid feed inlet is arranged at the top of the reaction section of the lactic acid esterification tower and reacts with the low-carbon alcohol, the top of the lactic acid esterification tower obtains a high-purity lactate product, and excessive lactic acid and polylactic acid are extracted from the kettle of the lactic acid esterification tower and enter the lactic acid dehydration tower; the lactic acid feeding port is arranged at the upper part of the reaction section of the lactic acid dehydration tower, the top of the lactic acid dehydration tower is provided with a water extraction pipeline for extracting product water, and the bottom of the lactic acid dehydration tower is provided with a circulating polylactic acid extraction pipeline for returning to the lactic acid esterification tower; wherein the reactant ethanol of the lactate exists only in the lactate esterification tower, and the reaction product water of lactic acid polymerization exists only in the lactic acid dehydration tower; the rectifying section of the lactic acid esterification tower and the internal parts of the stripping section of the lactic acid esterification tower are filler or tray; the internal components of the reaction section of the lactic acid esterification tower are strapping packing, modularized catalytic rectification structured packing or a lactic acid esterification tower tray; the rectifying section of the lactic acid dehydration tower and the rectifying section of the lactic acid dehydration tower are filled with packing or trays, and the inner parts of the reaction section of the lactic acid dehydration tower are packed with packing, modularized catalytic rectification structured packing or lactic acid dehydration trays.
2. The apparatus for producing lactic acid esters by reactive distillation according to claim 1, wherein the number of plates of the esterification column is 20 to 50, wherein the number of plates of the distillation section is 5 to 15, the number of plates of the reaction section is 10 to 40, and the number of plates of the stripping section is 2 to 15.
3. The apparatus for producing lactic acid esters by reactive distillation according to claim 1, wherein the number of trays in the lactic acid dehydrating column is 20 to 50, wherein the number of trays in the rectifying section is 5 to 15, the number of trays in the reaction section is 10 to 40, and the number of trays in the stripping section is 2 to 15.
4. The reactive distillation apparatus for producing lactic acid esters according to claim 1, wherein the operation pressure of the lactic acid esterification column is 0.02 to 0.5atm, and the reflux ratio is 0.1 to 1.3; the temperature of the tower top is 45-70 ℃, the temperature of the tower bottom is 100-126 ℃, and the temperature of the reaction section is 70-110 ℃.
5. The reactive distillation production device of lactate according to claim 1, wherein the residence time of the reaction material in each theoretical stage of the reaction section of the lactate esterification tower is 20-100 seconds, the reaction section is filled with macroporous strong acid resin particle solid catalyst, and the catalyst filling amount is 0.2-0.6 m 3 catalyst/m 3 reaction section.
6. The reactive distillation apparatus for producing lactic acid esters according to claim 1, wherein the operation pressure of the lactic acid dehydrating tower is 0.02 to 0.5atm, and the reflux ratio is 0.5 to 4; the temperature of the tower top is 45-90 ℃, the temperature of the tower bottom is 125-140 ℃, and the temperature of the reaction section is 70-120 ℃.
7. The reactive distillation production device of lactate according to claim 1, wherein the residence time of the reaction material in each theoretical stage of the reaction section of the lactic acid dehydration tower is 20-100 seconds, the reaction section is filled with macroporous strong acid resin particle solid catalyst, and the catalyst filling amount is 0.2-0.6m 3 catalyst/m 3 reaction section.
8. The reactive distillation production device of lactate esters according to claim 1, wherein the molar ratio of raw material low-carbon alcohol to lactic acid is 1:1.3-1:8.
9. The apparatus for producing lactic acid esters by reactive distillation according to claim 1, wherein the molar ratio of the lower alcohol of the reactant to lactic acid in the reaction section of the esterification column is always less than 0.5.
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| US20070203358A1 (en) * | 2006-02-28 | 2007-08-30 | Hendrik Dirkzwager | Process for reactive distillation of a carboxylic acid |
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| CN213050530U (en) * | 2020-08-15 | 2021-04-27 | 天津大学 | High-efficiency energy-saving ethyl lactate reaction rectification production device |
| CN112934148A (en) * | 2019-11-26 | 2021-06-11 | 南京华基塔业有限公司 | Reaction system and method for oligomerization of lactic acid |
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| US20070203358A1 (en) * | 2006-02-28 | 2007-08-30 | Hendrik Dirkzwager | Process for reactive distillation of a carboxylic acid |
| US20110144378A1 (en) * | 2007-12-05 | 2011-06-16 | Nanjing University | Catalytic reaction-rectification integrated process and specialized device thereof |
| US20130240346A1 (en) * | 2010-10-14 | 2013-09-19 | Nanjing University | Anti-thermosensitization rectification tower and the rectification process thereof for separating thermosensitive natural substances |
| CN110935186A (en) * | 2019-11-12 | 2020-03-31 | 临沂市金沂蒙生物科技有限公司 | Novel heat coupling rectification process in acetate production process |
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