CN111484408A

CN111484408A - Preparation device and method of lauric acid monoglyceride, control system and method

Info

Publication number: CN111484408A
Application number: CN202010458435.6A
Authority: CN
Inventors: 罗凯文; 周建平; 谢小玲
Original assignee: Guangzhou Kevin Food Co ltd
Current assignee: GUANGDONG KAIWEN BIOLOGICAL TECHNOLOGY Co.,Ltd.
Priority date: 2020-05-26
Filing date: 2020-05-26
Publication date: 2020-08-04

Abstract

The invention discloses a preparation device and method of glycerol monolaurate, a control system and a control method. According to the preparation device of the monoglyceride laurate, the computer adopts 14-point temperature acquisition, 8-point pressure acquisition and 1-point PH acquisition, and the opening degree of 14 valves is controlled. The preparation device of the lauric acid monoglyceride has high automation level, the acquired data are comprehensive and accurate, the multidimensional analysis and control of temperature, pressure and PH are carried out, and the product quality and the production efficiency are improved. The preparation method is a method for preparing the glycerol monolaurate by carrying out esterification reaction on glycerol and lauric acid at high temperature under the condition of nitrogen or carbon dioxide, the method does not use a catalyst, no phosphate is generated in the reaction process, no pollution is caused to the environment, the reaction equipment is totally closed, the environment is friendly, and the generated recovered glycerol is recycled as a reactant for the next reaction, so that the production cost can be reduced.

Description

Preparation device and method of lauric acid monoglyceride, control system and method

Technical Field

The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation device and method, a control system and a control method of monoglycerol laurate.

Background

Lauric monoglyceride, also known as lauric monoglyceride, having the molecular formula C₁₁H₂₃COOCH₂CHOHCH₂OH, a lipophilic nonionic surfactant, is a compound naturally found in some plants. After extraction, the extract is often used as a bactericide and an anti-inflammatory agent to be added into food, daily necessities or cosmetics. The monoglyceride laurate with monoester content of more than 96 percent has very excellent performance in the aspects of food preservation and emulsification, is not limited by PH, still has good antibacterial effect under the neutral to slightly alkaline condition, and researches show that the monoglyceride laurate has good inhibitory effect on bacteria, mould, microzyme, fungi and other microorganisms.

Among the methods for preparing monoglycerides of lauric acid, esterification is one of the more commonly used methods. The catalyst for esterification reaction mainly comprises enzyme, traditional strong acid, ion exchange resin, ionic liquid and the like. The catalyst has the problems of long reaction time, high corrosivity, environmental pollution, more byproducts, high cost and the like in the catalytic esterification reaction, and H is used in the traditional industry₃PO₄And in the process of removing the basic catalyst from the reaction system by using traditional strong acid such as HC L and the like, ionic liquid, heteropoly acid and the like, the generated phosphate has great pollution to the environment, so that the development of a green and environment-friendly method for efficiently preparing the monoglyceride laurate is of great significance.

The conventional preparation method is widely applied in a direct esterification method: the glycerol and the lauric acid are reacted for 2 to 4 hours at the temperature of 160 ℃ and 180 ℃ under the catalysis of alkali (such as NaOH and KOH), so that a mixture with the content of the glycerol monolaurate of about 50 percent is obtained.

Disclosure of Invention

In order to solve the defects and shortcomings of the prior art, the invention aims to provide the preparation device of the monoglycerol laurate, which has the advantages of high reaction speed, short production period, less byproducts, good product quality, light color, high yield and low production cost compared with the traditional reaction kettle, and the reaction time is half of that of the traditional reaction kettle.

The second purpose of the invention is to provide a preparation method of glycerol monolaurate, which is a method for preparing glycerol monolaurate by carrying out esterification reaction on glycerol and lauric acid at high temperature under the condition of nitrogen or carbon dioxide, and the method does not use a catalyst, does not generate phosphate in the reaction process, has no pollution to the environment, solves the problem that the phosphate generated by the traditional process needs to be discharged to cause environmental pollution, and can reduce the production cost because the reaction equipment is totally closed and environment-friendly, and the generated recovered glycerol is recycled as a reactant for the next reaction.

The third purpose of the invention is to provide a control system for preparing the glycerol monolaurate, which can effectively and accurately control the feeding amount of each material in the glycerol monolaurate and the water inflow of cooling water by adopting a mode of controlling the whole control system by taking a computer as a core, and can also accurately control the reaction temperature, the pressure and the pH value.

The fourth purpose of the invention is to provide a control method for preparing the glycerol monolaurate.

The primary purpose of the invention is realized by the following technical scheme:

a preparation device of monoglycerol laurate comprises a production device of monoglycerol laurate, a distillation device of monoglycerol laurate and a powder spraying device of monoglycerol laurate.

The production device of the lauric monoglyceride comprises an external circulation heat exchanger, a reaction tank, a condensation component, a loop circulating pump, a valve and a detection device, wherein a loop reaction mixer is arranged in the reaction tank, the top of the external circulation heat exchanger is connected with the loop reaction mixer, the bottom of the external circulation heat exchanger is connected with the bottom of the reaction tank through the loop circulating pump, and the top of the reaction tank is connected with the condensation component; the top of the reaction tank is connected with the external circulation heat exchanger through a pipeline, the top of the reaction tank is provided with a feed pipeline and a feed valve, and the bottom of the reaction tank is provided with a discharge pipeline and a bottom valve; the top, the middle part and the bottom of the reaction tank are provided with a pressure detection device and a temperature detection device, and the bottom of the reaction tank is provided with a pH value detection device; the top of the reaction tank, an external circulation heat exchanger and a condensing assembly form a gas phase loop (a glycerol monolaurate loop) through a pipeline, the external circulation heat exchanger is provided with a temperature detection device, and the upper part of the condensing assembly is provided with a temperature detection device and a pressure detection device; the pressure detection device, the temperature detection device and the pH value detection device are all electrically connected with the computer.

Preferably, a gas phase discharge valve is arranged on a connecting pipeline between the middle part of the reaction tank and the condensation assembly, a control valve is arranged on the external circulation heat exchanger, and a master control valve is arranged on the condensation assembly.

Preferably, the condensation component comprises a primary condenser, a secondary condenser, a tertiary condenser, a primary condenser receiving tank, a secondary condenser receiving tank and a tertiary condenser receiving tank; the upper part of the first-stage condenser is provided with a cooling water outlet, the top of the first-stage condenser is connected with a condensed water inlet at the upper part of a second-stage condenser receiving tank, the lower part of the first-stage condenser is provided with a cooling water inlet, and cooling water is used for condensing gas from bottom to top; the upper part of the second-stage condenser is provided with a cooling water outlet, the top of the second-stage condenser is connected with an upper condensed water inlet of the third-stage condenser receiving tank, the lower part of the second-stage condenser is provided with a cooling water inlet, and cooling water is used for condensing gas from bottom to top; the upper part of the third-stage condenser is provided with a cooling water outlet, and the lower part of the third-stage condenser is provided with a cooling water inlet and a cooling water outlet; and a condensate water inlet at the upper part of the primary condenser receiving tank is connected with the upper part of the reaction tank.

Preferably, the top of the reaction tank is provided with a vacuum port, a glycerol inlet and a gas phase outlet, the upper part of the reaction tank is provided with a lauric acid inlet, the middle part of the reaction tank is also provided with a material outlet, and the bottom of the reaction tank is provided with a heat preservation coil pipe; and the material outlet of the reaction tank is connected with the bottom of the receiving tank of the secondary condenser.

Preferably, the loop reaction mixer is one of a spray mixer, a jet mixer or a venturi mixer.

The loop reactor of the spray mixer is represented by a gas-liquid contact reactor created by PRESS corporation, italy; the loop reactor of the venturi mixer is represented by a bosh reactor created by the company bus, switzerland.

Preferably, the upper part of the external circulation heat exchanger is provided with a heat conduction oil outlet, the lower part of the external circulation heat exchanger is provided with a heat conduction oil inlet, the top of the external circulation heat exchanger is connected with the top of the reaction tank, and the bottom of the external circulation heat exchanger is connected with the bottom of the reaction tank.

Preferably, the preparation device of the monoglycerol laurate further comprises a sedimentation liquid separation tank, and the upper part of the sedimentation liquid separation tank is connected with the bottom of the reaction tank through a pipeline and a loop circulating pump.

Preferably, the distillation device for the monoglycerides of lauric acid comprises a distillation process feed pump, a first molecular distillation device, a second molecular distillation device, a third molecular distillation device, a fourth molecular distillation device, an ester distillation discharge pump and an ester distillation precipitation tank, wherein the first molecular distillation device, the second molecular distillation device, the third molecular distillation device and the fourth molecular distillation device are arranged in sequence.

Preferably, the first molecular distillation device comprises a first molecular distillation column, a first-stage trap, a ditriester precipitation tank, a ditriester discharge pump and a storage tank, the top of the first-stage molecular distillation column is connected with a distillation process feeding pump, the upper part of the first-stage molecular distillation column is connected with the first-stage trap, the bottom of the first-stage trap is connected with the ditriester precipitation tank, and the ditriester precipitation tank is connected with the storage tank through the ditriester discharge pump.

Preferably, the second molecular distillation device comprises a second-stage rectification column, a second-stage trap and a ditriester precipitation tank I, wherein the top of the second-stage molecular distillation column is connected with the bottom of the first-stage molecular distillation column, the lower part of the second-stage molecular distillation column is connected with the second-stage trap, the bottom of the second-stage molecular distillation column is connected with the ditriester precipitation tank, and the lower part of the second-stage molecular distillation column is connected with the ditriester precipitation tank I.

Preferably, the third molecular distillation device comprises a third molecular distillation column, a third trap and a tri-tetra-ester settling tank, the top of the third molecular distillation column is connected with the di-tri-ester settling tank I, the third trap is connected with the lower part of the third molecular distillation column, the tri-tetra-ester settling tank is connected with the lower part of the third molecular distillation column, the bottom of the third molecular distillation column is connected with the di-tri-ester settling tank, the second and third air-separation cylinders are connected with the third trap, and the second and third hot oil pumps are connected with the middle part of the third molecular distillation column.

Preferably, the fourth molecular distillation device comprises a four-stage molecular distillation column, a four-stage trap, a booster pump and an ester evaporation buffer tank, the top of the four-stage molecular distillation column is connected with a three-four-ester precipitation tank, and the lower part of the distillation column is respectively connected with the four-stage trap and the ester evaporation buffer tank.

Preferably, the fourth molecular distillation device further comprises a ditriester precipitation tank II, a ditriester discharge pump and a storage tank, the bottom of the four-stage molecular distillation column is connected with the ditriester precipitation tank II, and the ditriester precipitation tank II is connected with the storage tank through the ditriester discharge pump.

Preferably, the distillation apparatus for monoglycerol laurate comprises three fourth molecular distillation apparatuses.

The lauric monoglyceride powder spraying device comprises a temporary ester steaming tank, a circulating ester steaming pump, a standing ester steaming tank, a storage ester steaming tank, a powder spraying pump, a powder spraying tower and an air cooler, wherein the temporary ester steaming tank is connected with a discharge ester steaming pump, the circulating ester steaming tank is respectively connected with the circulating ester steaming pump and the standing ester steaming tank, the standing ester steaming tank is sequentially connected with the storage ester steaming tank, the powder spraying pump and the powder spraying tower, and the air cooler is positioned at the lower part of the powder spraying tower and faces the powder spraying tower from bottom to top.

Preferably, the powder spraying device for the monoglycerol laurate further comprises a rotary vibration sieve, and the rotary vibration sieve is used for further sieving the produced finished monoglycerol laurate powder.

The second purpose of the invention is realized by the following technical scheme:

a preparation method of monoglyceride laurate comprises the following specific steps:

(1) mixing and preheating lauric acid and glycerol according to the molar ratio of 1: 1-3, adding the mixed solution into a monoglyceride laurate preparation device, and reacting under the protection of nitrogen or carbon dioxide to produce a monoglyceride laurate initial product containing 50-55 percent of monoglyceride laurate;

(2) and (2) performing four-stage molecular distillation on the initial lauric acid monoglyceride in the step (1) to obtain the monolaurin with the purity of 96-99%.

Preferably, the specific process flow of the step (1) is as follows:

the method comprises the steps of configuring lauric acid and glycerol in a molar ratio of 1: 1-3, starting a gas phase loop of a loop reactor, replacing nitrogen or carbon dioxide for at least two times, maintaining the pressure of the nitrogen or carbon dioxide of the whole loop reactor system at-0.09 MPa-0.2 MPa, enabling the glycerol to flow in through a glycerol inlet at the top of a reaction tank, enabling the lauric acid to flow in through a lauric acid inlet at the upper part of the reaction tank, mixing and heating the glycerol and the lauric acid in the reaction tank under the action of a loop reaction mixer for reaction, and controlling the temperature in the reaction tank to be 160-240 ℃; gas generated in the reaction tank and unreacted glycerin enter a first-stage condenser from the upper part of the reaction tank for condensation, the unreacted glycerin returns to the reaction tank to continue to react, the uncondensed gas passes through a second-stage condenser and a third-stage condenser, so that water in reaction byproducts is collected in a second-stage condenser receiving tank and a third-stage condenser receiving tank, and the temperature of the first-stage condenser (1001) in a gas phase loop is controlled to be 100 ℃, the temperature of the second-stage condenser (1002) is controlled to be 60 ℃, and the temperature of the third-stage condenser (1003) is controlled to be 30 ℃; the glycerol and the lauric acid materials at the bottom of the reaction tank are continuously pumped into an external circulation heat exchanger through a loop circulating pump for heat exchange; the gas after heat exchange enters the reaction tank through the top of the reaction tank; the loop reaction time is 2 to 8 hours, and when the pH value of the product detected by a pH value detection device at the lower part of the reaction tank is reduced to be below 5, the reaction is stopped; and (3) pumping the lauric monoglyceride crude product at the bottom of the reaction tank into a settling liquid separation tank by a loop circulating pump, cooling to 160-170 ℃, settling, separating, filtering and taking supernatant to obtain a lauric monoglyceride crude product containing 50-55% of lauric monoglyceride.

Preferably, the heat transfer oil is introduced through a heat transfer oil inlet at the lower part of the external circulation heat exchanger and flows out from a heat transfer oil outlet at the upper part of the external circulation heat exchanger to exchange heat.

Preferably, the glycerol and the lauric acid are mixed and reacted under the action of a loop reaction mixer.

Preferably, in the step (1), the molar ratio of lauric acid to glycerol is 1: 1, the reaction pressure of a reaction tank is 0.08MPa, the reaction temperature is 235 ℃, the reaction time is 5 hours, the temperature is reduced to 160 ℃, and sedimentation separation is carried out.

Preferably, in the step (1), the molar ratio of lauric acid to glycerol is 1: 1.5, the reaction pressure of a reaction tank is 0.05MPa, the reaction temperature is 225 ℃, the reaction time is 6h, the temperature is reduced to 160 ℃, and sedimentation separation is carried out.

Preferably, in the step (1), the molar ratio of lauric acid to glycerol is 1: 2, the reaction pressure of the reaction tank is-0.01 MPa, the reaction temperature is 215 ℃, the reaction time is 4h, the temperature is reduced to 160 ℃, and the sedimentation separation is carried out.

Preferably, in the step (1), the molar ratio of lauric acid to glycerol is 1: 3, the reaction pressure of a reaction tank is-0.08 MPa, the reaction temperature is 205 ℃, the reaction time is 8h, the temperature is reduced to 170 ℃, and settling separation is performed.

Preferably, the specific process flow of the four-stage molecular distillation of the initial lauric acid monoglyceride product in the step (2) is as follows:

the first-stage molecular distillation process comprises the following steps: the initial lauric acid monoglyceride separated in the step (1) enters from the top of a first-stage molecular distillation column through a distillation process feed pump, and is subjected to dehydration, degassing and glycerol process in the first-stage molecular distillation column, wherein the reaction temperature is 130-150 ℃, the vacuum degree is 200-300 Pa, a gas-phase component is condensed through a first-stage trap, then enters a ditriester precipitation tank through the bottom of the first-stage trap, and a liquid-phase component enters a second-stage molecular distillation column through the bottom of the first-stage molecular distillation column;

and (3) a secondary molecular distillation process: the crude ester dehydrated by the first-stage molecular distillation column and gas enters a second-stage molecular distillation column for further separation of glycerol, wherein the reaction temperature is 150-165 ℃, the vacuum degree is 150-190 Pa, the gas-phase component is condensed by a second-stage trap, the heavier liquid-phase component enters a ditriester precipitation tank through the bottom of the second-stage molecular distillation column, and the lighter liquid-phase component enters a ditriester precipitation tank I for precipitation through the lower part of the second-stage molecular distillation column;

and (3) a three-stage molecular distillation process: the crude ester of the glycerol separated by the second-level molecular distillation column enters a third-level molecular distillation column for further fatty acid separation, wherein the reaction temperature is 165-180 ℃, the vacuum degree is 30-50 Pa, gas-phase components are condensed by a third-level trap, a lighter liquid phase enters a tetratriacontyl ester precipitation tank through the lower part of the third-level molecular distillation column, and a heavier liquid-phase component enters a ditriester precipitation tank from the bottom of the distillation column;

four-stage molecular distillation process: the crude ester of the fatty acid separated by the tertiary molecular distillation column enters a quaternary molecular distillation column to further separate triester, wherein the reaction temperature is 170-190 ℃, the vacuum degree is 0-20 Pa, the gas-phase component enters a quaternary trap, the liquid phase with the lighter liquid phase enters a distilled ester buffer tank and then flows into a ditriester precipitation tank II, and most of the monolaurin enters the distilled ester precipitation tank through the bottom of the quaternary molecular distillation column; obtaining the monolaurin with the purity of 96-99 percent after four-stage distillation.

Preferably, the four-stage molecular distillation apparatus comprises three groups.

Preferably, the preparation method of the glycerol monolaurate further comprises the steps of drying glycerol monolaurate; and (3) storing the lauric glyceride in the ester steaming precipitation tank in an ester steaming temporary storage tank through an ester steaming discharge pump for further preparation.

Preferably, the lauric acid glyceride in the ester steaming temporary storage tank enters an ester steaming circulation tank for further dehydration, the dehydrated lauric acid monoglyceride enters an ester steaming standing tank for temporary storage, then the lauric acid monoglyceride in the ester steaming standing tank is further dehydrated under the action of an ester steaming circulation pump until the content of the lauric acid monoglyceride is lower than 1%, then the lauric acid monoglyceride with the water content lower than 1% is stored in an ester steaming storage tank, and is sprayed onto the top of a powder spraying tower through a powder spraying pump, and further drying is carried out under the action of an air cooler, so that the final product lauric acid monoglyceride powder is obtained.

The third purpose of the invention is realized by the following technical scheme:

a control system for preparing monoglyceride laurate comprises a computer, a temperature sensor group, pressure sensors, a pH sensor group, an electromagnetic valve group, an external circulation heat exchanger, a reaction tank, a condensation component, a loop circulation pump, a primary molecular distillation device, a secondary molecular distillation device, a tertiary molecular distillation device, a quaternary molecular distillation device, an ester evaporation temporary storage tank, an ester evaporation circulation tank, an ester evaporation standing tank, an ester evaporation storage tank and a powder spraying tower, wherein the temperature sensor group comprises at least fourteen temperature sensors, the pressure sensor group comprises at least eight pressure sensors, the pH sensor group comprises at least one pH sensor, and the electromagnetic valve group comprises at least fourteen electromagnetic valves;

a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on a connecting pipeline between the top of the reaction tank and the top of the external circulation heat exchanger; a temperature sensor, a pressure sensor, a pH value sensor and an electromagnetic valve are arranged on a connecting pipeline between the bottom of the reaction tank and the loop circulating pump; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged in the middle of the reaction tank and connected with the bottom of the condensing assembly; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on a pipeline connecting the condensation component and the top of the reaction tank; a temperature sensor is arranged on the external circulation heat exchanger; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on the primary molecular distillation device; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on the secondary molecular distillation device; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on the three-stage molecular distillation device; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged in the four-stage molecular distillation device; a temperature sensor and an electromagnetic valve are arranged in the ester steaming temporary storage tank; a temperature sensor and an electromagnetic valve are arranged in the ester evaporation circulating tank; a temperature sensor and an electromagnetic valve are arranged in the ester steaming standing tank; the temperature sensor and the electromagnetic valve are arranged in the ester steaming storage tank; the temperature sensor and the electromagnetic valve are arranged on the powder spraying tower; the computer is respectively connected with the temperature sensor group, the pressure sensor, the pH value sensor group, the electromagnetic valve group, the external circulation heat exchanger, the reaction tank, the condensation component, the loop circulating pump, the primary molecular distillation device, the secondary molecular distillation device, the tertiary molecular distillation device, the quaternary molecular distillation device, the ester steaming temporary storage tank, the ester steaming circulation tank, the ester steaming standing tank, the ester steaming storage tank and the powder spraying tower and is used for controlling the inlet and outlet of materials, and the conveying of cooling water and heat conducting oil.

Preferably, the temperature sensor and the pressure sensor are connected with a computer and arranged in the external circulation heat exchanger, the reaction tank, the condensing assembly, the first-stage molecular distillation device, the second-stage molecular distillation device, the third-stage molecular distillation device, the fourth-stage molecular distillation device, the temporary ester steaming tank, the ester steaming circulation tank, the ester steaming standing tank, the ester steaming storage tank and the powder spraying tower.

Preferably, the pH value sensor is connected with a computer and is arranged in the reaction tank.

Preferably, the control system for preparing the monoglycerol laurate further comprises an alarm, and the alarm is connected with a computer.

The fourth purpose of the invention is realized by the following technical scheme:

a control method for preparing monolaurate comprises setting thirteen loops on a computer, controlling a control valve for controlling the material inlet and outlet of a reaction tank according to the temperature and pressure value at the top of the reaction tank, controlling a control valve of an external circulation heat exchanger and a bottom valve of the reaction tank according to the pH value at the bottom of the reaction tank, controlling a master control valve of a condenser and a gas phase discharge valve of the reaction tank according to the temperature and pressure value at the middle part of the reaction tank, controlling a heating steam valve of the external circulation heat exchanger according to the temperature and pressure value at the bottom of the reaction tank, controlling a control valve for controlling the material inlet and outlet of a primary molecular distillation column according to the temperature and pressure value of a primary molecular distillation device, controlling a control valve for controlling the material inlet and outlet of a secondary molecular distillation column according to the temperature and pressure value of a secondary molecular distillation device, and controlling a control valve for controlling, the control valve controls the material inlet and outlet of the four-stage molecular distillation column according to the temperature and the pressure value of the four-stage molecular distillation device, controls the material inlet and outlet of the ester steaming temporary storage tank according to the temperature of the ester steaming temporary storage tank, controls the material inlet and outlet of the ester steaming circulation tank according to the temperature of the ester steaming circulation tank, controls the material inlet and outlet of the ester steaming standing tank according to the temperature of the ester steaming standing tank, controls the material inlet and outlet of the ester steaming storage tank according to the temperature of the ester steaming storage tank, and controls the material inlet and outlet of the ester steaming storage tank according to the temperature of the powder spray tower.

Preferably, the computer controlled method comprises the steps of: firstly, initializing a computer; setting an interrupt mode and an interrupt program, and receiving an interrupt action according to the program setting; setting a count value of a control point; collecting parameters of control points at regular intervals, and carrying out-of-tolerance programmed comparison and judgment on the collected parameters by a computer; if the judgment shows that the valve is out of tolerance, controlling the opening of the valve; if not, directly executing the next display program; and repeatedly executing the control process, and dynamically adjusting the states of all the acquisition points.

Preferably, the computer is + 1-level out of tolerance every time the set temperature exceeds 0- + n degrees centigrade or the pressure is 0- + mMPa or PH 0- + f of the allowed temperature; exceeding the allowable lower limit temperature of-n-0 ℃, or the pressure of-m-0 MPa or PH-f-0, and calculating as-1-level out-of-tolerance, wherein n and m are any numerical values; f is 0 to 14; the computer calculates the temperature, pressure and PH out-of-tolerance, and can drive the corresponding original position to generate an upward or downward displacement according to each level of out-of-tolerance, so as to change the size of the controlled valve.

Preferably, when the control point parameters are linkage control of a plurality of valves, a valve with priority control and a matched control valve are set; the valve opening value of the valve which is preferentially controlled is the difference of the product of the valve opening which is calculated by the computer and the relative influence system, subtracted by the total valve opening which is controlled cooperatively.

Preferably, the sampling method of the computer is set as a sampling period taking 1min as a control parameter, performing amplitude limiting filtering processing, then adopting median filtering processing, repeating the processing for 5-10 times, and taking the average value of the processing as the result of each sampling period.

The invention principle is as follows:

the process adopts molecular distillation, the temperature in the distillation process is low, and the separation purpose can be achieved as long as the temperature difference exists; the distillation vacuum degree is high, so that the material is not easy to oxidize and damage; the distilled liquid film is thin, the heat transfer efficiency is high, the energy consumption of the product is low, the heat loss in the whole separation process of molecular distillation is low, the internal pressure is extremely low, and the energy consumption can be greatly saved; the heating time of the material is short, the retention time at the distillation temperature is generally between a few seconds and dozens of seconds, and the chance of thermal decomposition of the material is reduced; the separation degree is higher, and the molecular distillation can separate substances which are not easy to separate conventionally; the molecular distillation has no boiling bubbling phenomenon, the molecular distillation is free evaporation on the surface of a liquid layer and is carried out under low pressure, and no dissolved air exists in the liquid, so that the whole liquid can not be boiled in the distillation process and no bubbling phenomenon exists; the whole production process is non-toxic, harmless, pollution-free and residue-free, and a pure and safe product can be obtained; can selectively evaporate the target product, remove other impurities, and can simultaneously separate more than 2 substances through multi-stage separation; the fractionation process of molecular distillation is a physical process and thus provides good protection against contamination and attack of the separated material.

Molecular distillation of lauric acid monoglyceride is carried out by separating unreacted small molecules such as glycerin and lauric acid from large molecules such as monoglyceride and diglyceride by molecular distillation under high temperature and high vacuum conditions. Then, the separated glyceride is subjected to secondary separation to continuously separate out unreacted micromolecules such as glycerol, lauric acid and the like, monoglyceride and diglyceride are separated out under the conditions of proper temperature and vacuum degree, the monoglyceride and diglyceride of lauric acid are purified through tertiary separation, and four-stage distillation is carried out to separate the monoglyceride and diglyceride of lauric acid to obtain monoglyceride with the purity of more than 96 percent, so that the monoglyceride meets the requirement of food grade, the high-purity monoglyceride also has excellent corrosion resistance, can be applied to special products needing to be added with preservatives and the like, and has wide market prospect.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the process adopts a preparation method of the lauric acid monoglyceride without using a catalyst, has the advantages that phosphate is not generated in the preparation process, the problem of environmental pollution caused by the phosphate in the prior art is solved, and the production cost can be reduced.

(2) The process uses more than 99.5 percent of nitrogen or high-purity carbon dioxide as protective gas in the reaction process, has the characteristics of no toxicity, no harm, no combustion, no pollution, easy recovery and cyclic utilization and the like, is environment-friendly green gas, and can effectively prevent the decomposition of saturated fatty acid and the color deepening at high temperature and reduce the peculiar smell and the odor of the product.

(3) Generally, the reaction of the traditional alkaline catalyst can generate phosphate and ester compounds which account for about 1 percent of the total amount of materials, which affect the quality of products, so the product must be discharged, and the environment can be polluted.

(4) Molecular distillation is a distillation in a non-equilibrium state, with advantages not comparable to conventional distillation. The molecular distillation has the advantages of high vacuum degree, low operation temperature, low steam pressure, removal of impurities and colors in raw materials or products, reduction of thermal damage of heat-sensitive substances, short heating time of separated substances, high product quality and yield, clean and environment-friendly process and the like. Can solve the problem which can not be solved by the traditional distillation and has very wide application prospect.

(5) The preparation process adopts a loop reaction device to replace the traditional stirred tank. The traditional stirring kettle is strengthened by mechanical stirring and gas bubbling, the temperature difference between the material temperature bottom and the liquid level at the top in the reaction kettle is usually 7-15 ℃, so that the molecular weight distribution is uneven, and a large number of byproducts are produced; the problems of gas-liquid-solid three-phase reaction mass transfer and heat transfer in the reaction process are solved; furthermore, the loop reactor has high reaction efficiency which is about 3 times of that of a kettle type reaction, and the production period can be shortened by more than 50 percent; comparison with the reaction kettle: because rotating equipment such as mechanical stirring and the like is not arranged, leakage is avoided, static electricity cannot be generated, and the safety performance is good; the traditional stirring kettle is strengthened by mechanical stirring and gas bubbling; the power consumption of the loop reactor is mainly a circulating pump, the reaction mainly occurs in a mixing nozzle, and the intimate mixing of a reaction zone generates uniform temperature and concentration distribution; the loop reaction mixer can be any one of a spray mixer, a jet mixer or a Venturi mixer; the product obtained by adopting the loop reaction has good quality, uniform molecular weight distribution, small temperature difference, high crude ester content of 55 percent, light color, shortened reaction time by 50 percent and high safety factor. The reaction kettle has the defects of poor mass transfer effect, more reaction byproducts, dark product color, heavy smell and long reaction time.

(6) According to the preparation device of the monoglyceride laurate, the computer adopts 14-point temperature acquisition, 8-point pressure acquisition and 1-point PH acquisition, and the opening degree of 14 valves is controlled. The preparation device of the lauric acid monoglyceride has high automation level, the acquired data are comprehensive and accurate, the multidimensional analysis and control of temperature, pressure and PH are carried out, and the product quality and the production efficiency are improved.

(7) The control system of the invention adopts a multi-point temperature acquisition device, a multi-point pressure acquisition device and a PH inspection device, and adopts a control model with a plurality of groups of control loops. The valves between the control loops are controlled in a priority mode, an influence system of the valves is set, and the opening degree of the priority valves is set according to the coefficient. By adopting the precise control mode, the mutual influence among all control loops is reduced. Compared with a single control loop, the controlled quantity of each control loop achieves high precision, and the influence of single system control on the whole system is eliminated. And further, the purposes of accurate control, yield improvement and product quality optimization can be achieved.

Drawings

FIG. 1 is a process flow diagram for preparing a crude monoglyceride laurate product;

FIG. 2 is a process flow chart for preparing 96% -99% of monoglyceride laurate;

FIG. 3 shows a production apparatus for monoglycerol laurate;

FIG. 4 shows a first molecular distillation apparatus to a third molecular distillation apparatus in a distillation apparatus of monoglycerol laurate;

FIG. 5 shows a fourth molecular distillation unit of a distillation unit of monoglycerol laurate;

FIG. 6 is a powder spraying device for monoglyceride laurate;

FIG. 7 is a process flow diagram of a control method for preparing monoglycerol laurate.

Wherein the device comprises a vacuum port-1, a glycerol inlet-2, a lauric acid inlet-3, a cooling water inlet-4, a cooling water outlet-5, a heat transfer oil outlet-6, a heat transfer oil inlet-7, an external circulation heat exchanger-8, a loop circulation pump-9, a primary condenser-1001, a secondary condenser-1002, a tertiary condenser-1003, a primary condenser receiving tank-1101, a secondary condenser receiving tank-1102, a tertiary condenser receiving tank-1103, a loop reaction mixer-12, a reaction tank-13, a sedimentation liquid separation tank-14, a heat preservation coil pipe-15, a distillation process feed pump-16, a primary molecular distillation column-17, a primary catcher-18, a ditriester precipitation tank-19, a ditriester discharge pump-20 and a first storage tank-21, a second-stage molecular distillation column-22, a second-stage trap-23, a ditriester precipitation tank I-24, a third-stage molecular distillation column-25, a third-stage trap-26, a tetratriester precipitation tank-27, a fourth-stage molecular distillation column-28, a fourth-stage trap-29, a distilled ester buffer tank-30, a ditriester precipitation tank II-31, a ditriester discharge pump-32, a second storage tank-33, a distilled ester precipitation tank-34, a distilled ester discharge pump-35, a distilled ester temporary storage tank-36, a flow meter-37, a distilled ester circulation tank-38, a distilled ester circulation pump-39, a distilled ester standing tank-40, a distilled ester storage tank-41, a powder injection pump-42, a powder injection tower-43, an air cooler-44 and a rotary vibration sieve-45.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto.

The invention aims to solve the problem of phosphate generated by the prior art (environmental pollution), and provides a method for preparing glycerol monolaurate by carrying out esterification reaction on glycerol and lauric acid at high temperature under the condition of nitrogen or carbon dioxide, wherein no catalyst is used in the method, so that no phosphate is generated in the reaction process, reaction equipment is totally closed, the method is environment-friendly, and the production cost can be reduced, and the monoester content detection method in the embodiments 2 to 5 is determined according to GB 1886.65-2015.

Example 1

In this embodiment, the preparation apparatus of monoglycerides of lauric acid includes a production apparatus of monoglycerides of lauric acid, a distillation apparatus of monoglycerides of lauric acid, and a powder spraying apparatus of monoglycerides of lauric acid.

As shown in fig. 3, the apparatus for producing monoglycerides of lauric acid comprises an external circulation heat exchanger, a reaction tank, a condensing assembly, a loop circulation pump, a valve and a detection device, wherein a loop reaction mixer (a gas-liquid contact reactor-spray type mixer created by PRESS, italy) is arranged in the reaction tank, the top of the external circulation heat exchanger is connected with the loop reaction mixer, the bottom of the external circulation heat exchanger is connected with the bottom of the reaction tank through the loop circulation pump, and the top of the reaction tank is connected with the condensing assembly; the top of the reaction tank is connected with the external circulation heat exchanger through a pipeline, the top of the reaction tank is provided with a feed pipeline and a feed valve, and the bottom of the reaction tank is provided with a discharge pipeline and a bottom valve; the top, the middle part and the bottom of the reaction tank are provided with a pressure detection device and a temperature detection device, and the bottom of the reaction tank is provided with a pH value detection device; the top of the reaction tank, an external circulation heat exchanger and a condensing assembly form a gas phase loop (a glycerol monolaurate loop) through a pipeline, the external circulation heat exchanger is provided with a temperature detection device, and the upper part of the condensing assembly is provided with a temperature detection device and a pressure detection device; the pressure detection device, the temperature detection device and the pH value detection device are all electrically connected with the computer.

In the device, a gas phase discharge valve is arranged on a connecting pipeline between the middle part of the reaction tank and the condensing assembly, a control valve is arranged on the external circulation heat exchanger, and a master control valve is arranged on the condensing assembly; the condensation component comprises a first-stage condenser, a second-stage condenser, a third-stage condenser, a first-stage condenser receiving tank, a second-stage condenser receiving tank and a third-stage condenser receiving tank; the upper part of the first-stage condenser is provided with a cooling water outlet, the top of the first-stage condenser is connected with a condensed water inlet at the upper part of a second-stage condenser receiving tank, the lower part of the first-stage condenser is provided with a cooling water inlet, and cooling water is used for condensing gas from bottom to top; the upper part of the second-stage condenser is provided with a cooling water outlet, the top of the second-stage condenser is connected with an upper condensed water inlet of the third-stage condenser receiving tank, the lower part of the second-stage condenser is provided with a cooling water inlet, and cooling water is used for condensing gas from bottom to top; the upper part of the third-stage condenser is provided with a cooling water outlet, and the lower part of the third-stage condenser is provided with a cooling water inlet and a cooling water outlet; and a condensate water inlet at the upper part of the primary condenser receiving tank is connected with the upper part of the reaction tank.

The top of a reaction tank of the device is provided with a vacuum port, a glycerol inlet and a gas phase outlet, the upper part of the reaction tank is provided with a lauric acid inlet, the middle part of the reaction tank is also provided with a material outlet, and the bottom of the reaction tank is provided with a heat preservation coil pipe; the material outlet of the reaction tank is connected with the bottom of the receiving tank of the secondary condenser; the upper part of the external circulation heat exchanger is provided with a heat conduction oil outlet, the lower part of the external circulation heat exchanger is provided with a heat conduction oil inlet, the top of the external circulation heat exchanger is connected with the top of the reaction tank, and the bottom of the external circulation heat exchanger is connected with the bottom of the reaction tank; the preparation device of the lauric monoglyceride further comprises a sedimentation liquid separation tank, and the upper part of the sedimentation liquid separation tank is connected with the bottom of the reaction tank through a pipeline and a loop circulating pump.

In this embodiment, as shown in fig. 4 to 5, the distillation apparatus for monoglyceryl laurate includes a distillation process feed pump, a first molecular distillation apparatus, a second molecular distillation apparatus, a third molecular distillation apparatus, a fourth molecular distillation apparatus, an ester distillation discharge pump, and an ester distillation settling tank, and the first molecular distillation apparatus, the second molecular distillation apparatus, the third molecular distillation apparatus, and the fourth molecular distillation apparatus are sequentially disposed.

In the device, a first molecular distillation device comprises a first-stage molecular distillation column, a first-stage trap, a ditridecyl precipitation tank, a ditridecyl discharge pump and a storage tank, wherein the top of the first-stage molecular distillation column is connected with a distillation process feeding pump, the upper part of the first-stage molecular distillation column is connected with the first-stage trap, the bottom of the first-stage trap is connected with the ditridecyl precipitation tank, and the ditridecyl precipitation tank is connected with the storage tank through the ditridecyl discharge pump;

the second molecular distillation device comprises a second-stage rectifying column, a second-stage catcher and a ditriester precipitation tank I, wherein the top of the second-stage molecular distillation column is connected with the bottom of the first-stage molecular distillation column, the lower part of the second-stage molecular distillation column is connected with the second-stage catcher, the bottom of the second-stage molecular distillation column is connected with the ditriester precipitation tank, and the lower part of the second-stage molecular distillation column is connected with the ditriester precipitation tank I;

the third molecular distillation device comprises a three-stage molecular distillation column, a three-stage trap and a three-four ester settling tank, the top of the three-stage molecular distillation column is connected with the ditriester settling tank I, the three-stage trap is connected with the lower part of the three-stage molecular distillation column, the three-four ester settling tank is connected with the lower part of the three-stage molecular distillation column, the bottom of the three-stage molecular distillation column is connected with the ditriester settling tank, the two three-stage branch cylinder is connected with the three-stage trap, and the two three-stage hot oil pump is connected with the middle part of the three;

the fourth molecular distillation device comprises a four-stage molecular distillation column, a four-stage catcher, a booster pump and an ester evaporation buffer tank, wherein the top of the four-stage molecular distillation column is connected with a three-four ester precipitation tank, and the lower part of the distillation column is respectively connected with the four-stage catcher and the ester evaporation buffer tank;

Preferably, the distillation device for the monoglycerol laurate comprises three fourth molecular distillation devices.

In this embodiment, the powder spraying device for monoglycerides of lauric acid comprises a temporary ester steaming tank, a circulating ester steaming pump, a standing ester steaming tank, a storage ester steaming tank, a powder spraying pump, a powder spraying tower and an air cooler, wherein the temporary ester steaming tank is connected to a discharging ester steaming pump, the circulating ester steaming tank is respectively connected to the circulating ester steaming pump and the standing ester steaming tank, the standing ester steaming tank is sequentially connected to the storage ester steaming tank, the powder spraying pump and the powder spraying tower, and the air cooler is located at the lower part of the powder spraying tower and faces the powder spraying tower from bottom to top.

Example 2

The preparation method of monoglycerol laurate in the embodiment comprises the following specific steps:

(1) as shown in fig. 1 to 6, lauric acid and glycerol are configured according to a molar ratio of 1: 1, a gas phase loop of a loop reactor is opened, nitrogen or carbon dioxide is replaced for at least two times, the pressure of the nitrogen or carbon dioxide of the whole loop reactor system is maintained to be 0.08MPa, glycerol flows in through a glycerol inlet at the top of a reaction tank, lauric acid flows in through a lauric acid inlet at the upper part of the reaction tank, the glycerol and the lauric acid are mixed and heated to react in the reaction tank under the action of a loop reaction mixer, and the temperature in the reaction tank is controlled to be 160-240 ℃; gas generated in the reaction tank and unreacted glycerin enter a first-stage condenser from the upper part of the reaction tank for condensation, the unreacted glycerin returns to the reaction tank to continue to participate in the reaction, and the uncondensed gas passes through a second-stage condenser and a third-stage condenser, so that water in reaction byproducts is collected in a second-stage condenser receiving tank and a third-stage condenser receiving tank, and the temperature of the first-stage condenser in a gas phase loop is controlled to be 100 ℃, the temperature of the second-stage condenser is controlled to be 60 ℃, and the temperature of the third-stage condenser is controlled to; the glycerol and the lauric acid materials at the bottom of the reaction tank are continuously pumped into an external circulation heat exchanger through a loop circulating pump for heat exchange; the gas after heat exchange enters the reaction tank through the top of the reaction tank; the loop reaction time is 5h, and when the pH value of the product is detected to be reduced to below 5 by a pH value detection device at the lower part of the reaction tank, the reaction is stopped; and (3) pumping a product of the coarse product of the monoglycerol laurate at the bottom of the reaction tank into a settling liquid separation tank by a loop circulating pump, cooling to 160 ℃, settling and separating, and filtering to obtain a supernatant fluid to obtain a initial product of the monoglycerol laurate containing 51.9 percent of the monoglycerol laurate.

(2) And (2) performing four-stage molecular distillation on the initial lauric acid monoglyceride product obtained in the step (1), wherein the specific distillation process is a first-stage molecular distillation process: the initial lauric acid monoglyceride separated in the step (1) enters from the top of a first-stage molecular distillation column through a distillation process feed pump, and is subjected to dehydration, degassing and glycerol process in the first-stage molecular distillation column, wherein the reaction temperature is 150-165 ℃, the vacuum degree is 150-190 Pa, a gas-phase component is condensed through a first-stage trap and then enters a ditriester precipitation tank through the bottom of the first-stage trap, and a liquid-phase component enters a second-stage molecular distillation column through the bottom of the first-stage molecular distillation column;

and (3) a secondary molecular distillation process: the crude ester dehydrated by the first-stage molecular distillation column and gas enters a second-stage molecular distillation column for further separation of glycerol, wherein the reaction temperature is 165-180 ℃, the vacuum degree is 30-50 Pa, the gas-phase component is condensed by a second-stage trap, the heavier liquid-phase component enters a ditriester precipitation tank through the bottom of the second-stage molecular distillation column, and the lighter liquid-phase component enters a ditriester precipitation tank I for precipitation through the lower part of the second-stage molecular distillation column;

and (3) a three-stage molecular distillation process: the crude ester of the glycerol separated by the second-level molecular distillation column enters a third-level molecular distillation column for further fatty acid separation, wherein the reaction temperature is 170-190 ℃, the vacuum degree is 0-20 Pa, the gas-phase components are condensed by a third-level trap, the lighter liquid phase enters a tetratriacid precipitation tank through the lower part of the third-level molecular distillation column, and the heavier liquid-phase components enter a ditrimethylene precipitation tank from the bottom of the distillation column;

four-stage molecular distillation process: the crude ester of the fatty acid separated by the tertiary molecular distillation column enters a quaternary molecular distillation column to further separate triester, wherein the reaction temperature is 170-190 ℃, the vacuum degree is 0-20 Pa, the gas-phase component enters a quaternary trap, the liquid phase with the lighter liquid phase enters a distilled ester buffer tank and then flows into a ditriester precipitation tank II, and most of the monolaurin enters the distilled ester precipitation tank through the bottom of the quaternary molecular distillation column; after four-stage distillation, lauric acid monoglyceride with a purity of 97.2% was obtained (according to GB 1886.65-2015).

Example 3

(1) as shown in fig. 1 to 6, lauric acid and glycerol are configured in a molar ratio of 1: 1.5, a gas phase loop of a loop reactor is opened, nitrogen or carbon dioxide is replaced for a system at least twice, the pressure of the nitrogen or carbon dioxide of the whole loop reactor system is maintained to be 0.05MPa, glycerol flows in through a glycerol inlet at the top of a reaction tank, lauric acid flows in through a lauric acid inlet at the upper part of the reaction tank, the glycerol and the lauric acid are mixed and heated to react in the reaction tank under the action of a loop reaction mixer, and the temperature in the reaction tank is controlled to be 225 ℃; gas generated in the reaction tank and unreacted glycerin enter a first-stage condenser from the upper part of the reaction tank for condensation, the unreacted glycerin returns to the reaction tank to continue to participate in the reaction, and the uncondensed gas passes through a second-stage condenser and a third-stage condenser, so that water in reaction byproducts is collected in a second-stage condenser receiving tank and a third-stage condenser receiving tank, and the temperature of the first-stage condenser in a gas phase loop is controlled to be 100 ℃, the temperature of the second-stage condenser is controlled to be 60 ℃, and the temperature of the third-stage condenser is controlled to; the glycerol and the lauric acid materials at the bottom of the reaction tank are continuously pumped into an external circulation heat exchanger through a loop circulating pump for heat exchange; the gas after heat exchange enters the reaction tank through the top of the reaction tank; the loop reaction time is 6 hours, and when the pH value of the product detected by the pH value detection device at the lower part of the reaction tank is reduced to be below 5, the reaction is stopped; and (3) pumping a product of the coarse product of the monoglycerol laurate at the bottom of the reaction tank into a settling liquid separation tank by a loop circulating pump, cooling to 160 ℃, settling and separating, and filtering to obtain a supernatant fluid to obtain a 53.6 percent initial product of the monoglycerol laurate.

(2) And (2) performing four-stage molecular distillation on the initial lauric acid monoglyceride product obtained in the step (1), wherein the specific distillation process is a first-stage molecular distillation process: the initial lauric acid monoglyceride separated in the step (1) enters from the top of a first-stage molecular distillation column through a distillation process feed pump, and is subjected to dehydration, degassing and glycerol process in the first-stage molecular distillation column, wherein the reaction temperature is 130-150 ℃, the vacuum degree is 200-300 Pa, a gas-phase component is condensed through a first-stage trap, then enters a ditriester precipitation tank through the bottom of the first-stage trap, and a liquid-phase component enters a second-stage molecular distillation column through the bottom of the first-stage molecular distillation column;

four-stage molecular distillation process: the crude ester of the fatty acid separated by the tertiary molecular distillation column enters a quaternary molecular distillation column to further separate triester, wherein the reaction temperature is 170-190 ℃, the vacuum degree is 0-20 Pa, the gas-phase component enters a quaternary trap, the liquid phase with the lighter liquid phase enters a distilled ester buffer tank and then flows into a ditriester precipitation tank II, and most of the monolaurin enters the distilled ester precipitation tank through the bottom of the quaternary molecular distillation column; after four-stage distillation, lauric acid monoglyceride with a purity of 98.6% was obtained (according to GB 1886.65-2015).

Example 4

(1) as shown in fig. 1 to 6, lauric acid and glycerol are configured in a molar ratio of 1: 2, a gas phase loop of a loop reactor is opened, nitrogen or carbon dioxide is replaced for at least two times, the pressure of nitrogen or carbon dioxide of the whole loop reactor system is maintained to be-0.01 MPa, glycerol flows in through a glycerol inlet at the top of a reaction tank, lauric acid flows in through a lauric acid inlet at the upper part of the reaction tank, glycerol and lauric acid are mixed and heated to react in the reaction tank under the action of a loop reaction mixer, and the temperature in the reaction tank is controlled to be 215 ℃; gas generated in the reaction tank and unreacted glycerin enter a first-stage condenser from the upper part of the reaction tank for condensation, the unreacted glycerin returns to the reaction tank to continue to participate in the reaction, and the uncondensed gas passes through a second-stage condenser and a third-stage condenser, so that water in reaction byproducts is collected in a second-stage condenser receiving tank and a third-stage condenser receiving tank, and the temperature of the first-stage condenser in a gas phase loop is controlled to be 100 ℃, the temperature of the second-stage condenser is controlled to be 60 ℃, and the temperature of the third-stage condenser is controlled to; the glycerol and the lauric acid materials at the bottom of the reaction tank are continuously pumped into an external circulation heat exchanger through a loop circulating pump for heat exchange; the gas after heat exchange enters the reaction tank through the top of the reaction tank; the loop reaction time is 4 hours, and when the pH value of the product detected by the pH value detection device at the lower part of the reaction tank is reduced to be below 5, the reaction is stopped; and (3) pumping a product of the coarse product of the monoglycerol laurate at the bottom of the reaction tank into a settling liquid separation tank by a loop circulating pump, cooling to 160 ℃, settling and separating, and filtering to obtain a supernatant fluid to obtain a primary product of the monoglycerol laurate containing 54.8 percent of the monoglycerol laurate.

four-stage molecular distillation process: the crude ester of the fatty acid separated by the tertiary molecular distillation column enters a quaternary molecular distillation column to further separate triester, wherein the reaction temperature is 170-190 ℃, the vacuum degree is 0-20 Pa, the gas-phase component enters a quaternary trap, the liquid phase with the lighter liquid phase enters a distilled ester buffer tank and then flows into a ditriester precipitation tank II, and most of the monolaurin enters the distilled ester precipitation tank through the bottom of the quaternary molecular distillation column; after four-stage distillation, lauric acid monoglyceride with the purity of 98.9% is obtained (the content detection method is according to GB 1886.65-2015).

Example 5

(1) as shown in fig. 1 to 6, lauric acid and glycerol are configured according to a molar ratio of 1: 3, a gas phase loop of a loop reactor is opened, nitrogen or carbon dioxide is replaced for at least two times, the pressure of the nitrogen or carbon dioxide of the whole loop reactor system is maintained at-0.08 MPa, glycerol flows in through a glycerol inlet at the top of a reaction tank, lauric acid flows in through a lauric acid inlet at the upper part of the reaction tank, the glycerol and the lauric acid are mixed and heated in the reaction tank under the action of a loop reaction mixer for reaction, and the temperature in the reaction tank is controlled to be 205 ℃; gas generated in the reaction tank and unreacted glycerin enter a first-stage condenser from the upper part of the reaction tank for condensation, the unreacted glycerin returns to the reaction tank to continue to participate in the reaction, and the uncondensed gas passes through a second-stage condenser and a third-stage condenser, so that water in reaction byproducts is collected in a second-stage condenser receiving tank and a third-stage condenser receiving tank, and the temperature of the first-stage condenser in a gas phase loop is controlled to be 100 ℃, the temperature of the second-stage condenser is controlled to be 60 ℃, and the temperature of the third-stage condenser is controlled to; the glycerol and the lauric acid materials at the bottom of the reaction tank are continuously pumped into an external circulation heat exchanger through a loop circulating pump for heat exchange; the gas after heat exchange enters the reaction tank through the top of the reaction tank; the loop reaction time is 8h, and when the pH value of the product detected by the pH value detection device at the lower part of the reaction tank is reduced to be below 5, the reaction is stopped; and (3) pumping a product of the coarse product of the monoglycerol laurate at the bottom of the reaction tank into a settling liquid separation tank by a loop circulating pump, cooling to 170 ℃, settling and separating, and filtering to obtain a supernatant fluid to obtain a 53.5 percent initial product of the monoglycerol laurate.

four-stage molecular distillation process: the crude ester of the fatty acid separated by the tertiary molecular distillation column enters a quaternary molecular distillation column to further separate triester, wherein the reaction temperature is 170-190 ℃, the vacuum degree is 0-20 Pa, the gas-phase component enters a quaternary trap, the liquid phase with the lighter liquid phase enters a distilled ester buffer tank and then flows into a ditriester precipitation tank II, and most of the monolaurin enters the distilled ester precipitation tank through the bottom of the quaternary molecular distillation column; after four-stage distillation, the lauric acid monoglyceride with the purity of 97.5 percent is obtained (the content detection method is according to GB 1886.65-2015).

Example 6

As shown in fig. 3 to fig. 6, the control system for preparing monoglycerides of lauric acid according to this embodiment includes a computer, a temperature sensor group, a pressure sensor, a ph sensor group, an electromagnetic valve group, an external circulation heat exchanger, a reaction tank, a condensing assembly, a loop circulation pump, a first-order molecular distillation apparatus, a second-order molecular distillation apparatus, a third-order molecular distillation apparatus, a fourth-order molecular distillation apparatus, a temporary ester distillation tank, a temporary ester distillation circulation tank, a standing ester distillation tank, a storage ester distillation tank, and a powder spray tower, where the temperature sensor group includes at least fourteen temperature sensors, the pressure sensor group includes at least eight pressure sensors, the ph sensor group includes at least one ph sensor, and the electromagnetic valve group includes at least fourteen electromagnetic valves.

A temperature sensor, a pressure sensor and an electromagnetic valve are arranged on a connecting pipeline between the top of the reaction tank and the top of the external circulation heat exchanger; a temperature sensor, a pressure sensor, a pH value sensor and an electromagnetic valve are arranged on a connecting pipeline between the bottom of the reaction tank and the loop circulating pump; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged in the middle of the reaction tank and connected with the bottom of the condensing assembly; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on a pipeline connecting the condensation component and the top of the reaction tank; a temperature sensor is arranged on the external circulation heat exchanger; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on the primary molecular distillation device; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on the secondary molecular distillation device; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged on the three-stage molecular distillation device; a temperature sensor, a pressure sensor and an electromagnetic valve are arranged in the four-stage molecular distillation device; a temperature sensor and an electromagnetic valve are arranged in the ester steaming temporary storage tank; a temperature sensor and an electromagnetic valve are arranged in the ester evaporation circulating tank; a temperature sensor and an electromagnetic valve are arranged in the ester steaming standing tank; the temperature sensor and the electromagnetic valve are arranged in the ester steaming storage tank; the temperature sensor and the electromagnetic valve are arranged on the powder spraying tower.

The computer is respectively connected with the temperature sensor group, the pressure sensor, the pH value sensor group, the electromagnetic valve group, the external circulation heat exchanger, the reaction tank, the condensation component, the loop circulating pump primary molecular distillation device, the secondary molecular distillation device, the tertiary molecular distillation device, the quaternary molecular distillation device, the ester steaming temporary storage tank, the ester steaming circulation tank, the ester steaming standing tank, the ester steaming storage tank and the powder spraying tower and is used for controlling the inlet and outlet of materials, and the conveying of cooling water and heat conducting oil.

Example 7

In the control method for preparing monoglyceryl laurate in the embodiment, as shown in fig. 7, a computer is provided with 4 loops, a control valve for controlling the material inlet and outlet of a reaction tank according to the temperature and pressure values at the top of the reaction tank, a control valve for controlling an external circulation heat exchanger and a bottom valve of the reaction tank according to the ph value at the bottom of the reaction tank in a linkage manner, a master control valve for controlling a condenser and a gas phase discharge valve of the reaction tank at the middle in a linkage manner according to the temperature and pressure values at the middle of the reaction tank, and a heating steam valve of the external circulation heat exchanger according to the temperature and pressure devices at the bottom of.

In this embodiment, the computer control method includes the steps of:

firstly, initializing a computer; setting an interrupt mode and an interrupt program, and receiving an interrupt action according to the program setting; setting a count value of a control point; collecting parameters of control points at regular intervals, and carrying out-of-tolerance programmed comparison and judgment on the collected parameters by a computer; if the judgment shows that the valve is out of tolerance, controlling the opening of the valve; if not, directly executing the next display program; and repeatedly executing the control process, and dynamically adjusting the states of all the acquisition points.

Setting the plus 1-level out-of-tolerance for the computer when the temperature exceeds 0 to plus n ℃ of the allowable temperature or the pressure is 0 to plus mMPa or PH is 0 to plus f; exceeding the allowable lower limit temperature of-n-0 ℃, or the pressure of-m-0 MPa or PH-f-0, and calculating as-1-level out-of-tolerance, wherein n and m are any numerical values; f is 0 to 14; the computer calculates the temperature, pressure and PH out-of-tolerance, and can drive the corresponding original position to generate an upward or downward displacement according to each level of out-of-tolerance, so as to change the size of the controlled valve.

When the control point parameters are linkage control of a plurality of valves, setting a valve with priority control and a matched control valve; the valve opening value of the valve which is preferentially controlled is the difference of the product of the valve opening which is calculated by the computer and the relative influence system, subtracted by the total valve opening which is controlled cooperatively.

The computer sampling method is set as a sampling period taking 1min as a control parameter, amplitude limiting filtering processing is carried out, median filtering processing is adopted, the operation is repeated for 5-10 times, and the average value of the operation is taken as the result of each sampling period.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A preparation device of monoglycerol laurate is characterized by comprising a production device of monoglycerol laurate, a distillation device of monoglycerol laurate and a powder spraying device of monoglycerol laurate.

2. The preparation device of the monoglycerol laurate according to claim 1, which comprises an external circulation heat exchanger, a reaction tank, a condensing assembly, a loop circulating pump, a valve and a detection device, wherein a loop reaction mixer is arranged in the reaction tank, the top of the external circulation heat exchanger is connected with the loop reaction mixer, the bottom of the external circulation heat exchanger is connected with the bottom of the reaction tank through the loop circulating pump, and the top of the reaction tank is connected with the condensing assembly; the top of the reaction tank is connected with the external circulation heat exchanger through a pipeline, the top of the reaction tank is provided with a feed pipeline and a feed valve, and the bottom of the reaction tank is provided with a discharge pipeline and a bottom valve; the top, the middle part and the bottom of the reaction tank are provided with a pressure detection device and a temperature detection device, and the bottom of the reaction tank is provided with a pH value detection device; the top of the reaction tank, an external circulation heat exchanger and a condensing assembly form a gas phase loop (a glycerol monolaurate loop) through a pipeline, the external circulation heat exchanger is provided with a temperature detection device, and the upper part of the condensing assembly is provided with a temperature detection device and a pressure detection device; the pressure detection device, the temperature detection device and the pH value detection device are all electrically connected with the computer.

3. The apparatus for preparing monoglycerides of lauric acid according to claim 2, wherein the condensing module includes a primary condenser, a secondary condenser, a tertiary condenser, a primary condenser receiving tank, a secondary condenser receiving tank and a tertiary condenser receiving tank; the upper part of the first-stage condenser is provided with a cooling water outlet, the top of the first-stage condenser is connected with a condensed water inlet at the upper part of a second-stage condenser receiving tank, the lower part of the first-stage condenser is provided with a cooling water inlet, and cooling water is used for condensing gas from bottom to top; the upper part of the second-stage condenser is provided with a cooling water outlet, the top of the second-stage condenser is connected with an upper condensed water inlet of the third-stage condenser receiving tank, the lower part of the second-stage condenser is provided with a cooling water inlet, and cooling water is used for condensing gas from bottom to top; the upper part of the third-stage condenser is provided with a cooling water outlet, and the lower part of the third-stage condenser is provided with a cooling water inlet and a cooling water outlet; and a condensate water inlet at the upper part of the primary condenser receiving tank is connected with the upper part of the reaction tank.

4. The apparatus according to claim 1, wherein the distillation apparatus for monoglycerol laurate comprises a distillation process feed pump, a first molecular distillation apparatus, a second molecular distillation apparatus, a third molecular distillation apparatus, a fourth molecular distillation apparatus, a distilled ester discharge pump, and a distilled ester precipitation tank, and the first molecular distillation apparatus, the second molecular distillation apparatus, the third molecular distillation apparatus, and the fourth molecular distillation apparatus are arranged in this order.

5. A method for preparing monoglycerol laurate, which is characterized by using the device for preparing monoglycerol laurate according to claims 1 to 4, and comprises the following steps:

6. The preparation method of monoglycerol laurate according to claim 5, wherein the specific process flow of the step (1) is as follows:

7. The preparation method of monoglycerol laurate according to claim 5, wherein the specific process flow of the four-stage molecular distillation of the initial monoglycerol laurate product in the step (2) is as follows:

8. A control system for preparing monoglyceride laurate is characterized by comprising a computer, a temperature sensor group, a pressure sensor, a pH value sensor group, an electromagnetic valve group, an external circulation heat exchanger, a reaction tank, a condensation component, a loop circulation pump, a primary molecular distillation device, a secondary molecular distillation device, a tertiary molecular distillation device, a quaternary molecular distillation device, an ester distillation temporary storage tank, an ester distillation circulation tank, an ester distillation standing tank, an ester distillation storage tank and a powder spraying tower, wherein the temperature sensor group comprises at least fourteen temperature sensors, the pressure sensor group comprises at least eight pressure sensors, the pH value sensor group comprises at least one pH value sensor, and the electromagnetic valve group comprises at least fourteen electromagnetic valves;

9. The control system for preparing monoglycerol laurate according to claim 8, wherein the temperature sensor and the pressure sensor are connected with a computer and are arranged in an external circulation heat exchanger, a reaction tank, a condensing component, a primary molecular distillation device, a secondary molecular distillation device, a tertiary molecular distillation device, a quaternary molecular distillation device, a temporary ester distillation tank, a circulating ester distillation tank, a standing ester distillation tank, a storage ester distillation tank and a powder spraying tower.

10. A control method for preparing monoglyceryl laurate according to any one of claims 8 or 9, wherein the computer is provided with thirteen circuits, a control valve for controlling the entrance and exit of materials in the reaction tank based on the temperature and pressure values at the top of the reaction tank, a control valve for controlling the entrance and exit of materials in the external circulation heat exchanger and a bottom valve of the reaction tank in a linked manner based on the pH value at the bottom of the reaction tank, a master control valve for controlling the condenser and a gas phase discharge valve in the reaction tank in a linked manner based on the temperature and pressure values at the middle of the reaction tank, a heating steam valve for controlling the external circulation heat exchanger based on the temperature and pressure values at the bottom of the reaction tank, a control valve for controlling the entrance and exit of materials in the primary molecular distillation column based on the temperature and pressure values of the primary molecular distillation apparatus, a control valve for controlling the entrance and exit of materials in the secondary molecular distillation column based on the temperature and pressure values of the, the control valve controls the material inlet and outlet of the four-stage molecular distillation column according to the temperature and the pressure value of the four-stage molecular distillation device, controls the material inlet and outlet of the ester steaming temporary storage tank according to the temperature of the ester steaming temporary storage tank, controls the material inlet and outlet of the ester steaming circulation tank according to the temperature of the ester steaming circulation tank, controls the material inlet and outlet of the ester steaming standing tank according to the temperature of the ester steaming standing tank, controls the material inlet and outlet of the ester steaming storage tank according to the temperature of the ester steaming storage tank, and controls the material inlet and outlet of the ester steaming storage tank according to the temperature of the powder spray tower.