Continuous flow production system and method for producing salt-free amino acid surfactants

Abstract

The present application discloses a production system and a method for producing salt-free amino acid surfactants by continuous flow, comprising: an amidation reaction module arranged to carry out an amidation reaction, the module including at least one reactor unit with an input port arranged to input amino acid salt, acid chloride, liquid alkali and mother liquor processing liquid, and an output port arranged to output an amidation product; a post-treatment module connected to the output port of the reactor unit, the post-treatment module conveying the amidation product into the post-treatment module for separation and concentration treatment, the output line A of the post-treatment module being connected to a finished product tank, and the output line B of the post-treatment module discharging the mother liquor; and a mother liquor separation module including at least one separation unit, the output port of the separation unit discharging the separated salt, and the reflux port of the separation unit being connected to the input port of the reactor unit to reflux the mother liquor processing liquid. The present application can produce salt-free amino acid surfactants by full continuous flow, with low energy consumption, green and no wastewater discharge.

Description

[Technical field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to a Chinese patent application bearing application number 202210348694.2, filed with the State Intellectual Property Office of the People's Republic of China on April 1, 2022, and entitled "Production system and method for producing salt-free amino acid surfactant by continuous flow," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of chemical engineering, and more particularly to a production system and method for producing salt-free amino acid surfactants by continuous flow. [Background technology]

[0003] Amino acid surfactants are surfactants with mild anions, and have amide groups and amino acid structures as their structural features, so in addition to the basic performance of surfactants such as emulsification, cleaning, dispersion, foaming, penetration, and solubilization, they also have the advantages of being less irritating, less toxic, good biodegradable, and good biocompatibility, and are widely used in the fields of detergents, cosmetics, medicines, food, biology, materials, environmental protection, etc. As people's interest in the safety and mildness of surfactant products and the demand for environmental protection increase, such surfactants are increasingly valued and their application fields become wider and wider.

[0004] The synthesis methods of amino acid surfactants mainly include the Schotten-Baumann reaction, acid chloride method, fatty acid anhydride method, aliphatic nitrile hydrolysis method, enzyme method, etc., but the one currently used industrially is the acid chloride method, and its general process is to adopt the Schotten-Baumann reaction, and after amidation, add a large amount of inorganic acid to acidify and separate into multiple layers, obtain the oil layer-fatty acyl amino acid, and then add a base to neutralize and form a salt. In this process, production is generally carried out using a single batch reactor. In the traditional batch production, there are many production steps, the process is complicated, the product quality is unstable, and a large amount of waste acid water is generated, which are obvious disadvantages. In the Chinese patent application CN106748871A, an amino acid recycling technology to solve the acid water discharge was proposed to solve the wastewater discharge, but the technology is still batch production. Although continuous production is used in Chinese patent applications CN201310366274 and CN108003050A, fully continuous production of low-salt products has not been achieved, whereas low-salt amino acid surfactants are typically used in the high-end cleaning ingredients market. Summary of the Invention [Problem to be solved by the invention]

[0005] In response to the shortcomings of the prior art, the present application provides a production system and method for producing salt-free amino acid surfactants by continuous flow, in which the production system can realize full continuous flow production of salt-free amino acid surfactants, the process is simple and efficient to operate, does not discharge waste acid, the produced amino acid surfactant products have low free acid index, are salt-free and have stable quality, are easy to produce on a large scale, greatly reduce production costs, and realize a green and environmentally friendly production process without discharge of waste acid water. [Means for solving the problem]

[0006] In order to achieve the above objectives, the present application adopts the following technical solutions: In a first aspect, the present application provides a production system for producing salt-free amino acid surfactants by continuous flow, comprising: an amidation reaction module configured to perform an amidation reaction, the amidation reaction module including at least one reactor unit having an input port configured to input an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment liquid, and an output port configured to output an amidation product; a post-treatment module, the input port of which is connected to the discharge port of the reactor unit, the amidation product is transported into the post-treatment module for separation and concentration treatment, the discharge line A of the post-treatment module is connected to the finished product tank, and the discharge line B of the post-treatment module discharges the mother liquor; a mother liquor separation module including at least one separation unit, the inlet port of the separation unit is connected to the outlet B of the post-treatment module, the outlet port of the separation unit discharges the separated salt, and the reflux port of the separation unit is connected to the inlet port of the reactor unit, and the mother liquor separation module discharges the mother liquor treatment liquid and the separated salt after the mother liquor is treated in the separation unit; The present invention provides a production system including:

[0007] Further, the reactor unit is selected from any one or a combination of two or more of a microchannel reactor, a series coil pipe reactor, and a tubular reactor.

[0008] Preferably, the reactor units are set up in two, a microchannel reactor and a tubular reactor.

[0009] Further, the amidation reaction module includes a temperature section T1 and a temperature section T2, and the temperature ranges of the temperature sections T1 and T2 are 0 to 90°C.

[0010] Preferably, the temperature range of the temperature section T1 is 0 to 40°C, and the temperature range of the temperature section T2 is 60 to 90°C.

[0011] More preferably, the temperature range of the temperature section T1 is 0 to 15°C, and the temperature range of the temperature section T2 is 70 to 85°C.

[0012] Further, the post-treatment module includes a membrane separation device and a substance concentrator, the membrane separation device being selected from any one or a combination of two or more of a microfiltration membrane, an ultrafiltration membrane, and a nanofiltration membrane, and the substance concentrator being selected from any one or a combination of two or more of a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane, and an RO membrane (reverse osmosis membrane).

[0013] Preferably, the membrane separator and the substance concentrator are selected from an ultrafiltration membrane and a nanofiltration membrane, and the filtration pressure of the ultrafiltration membrane or nanofiltration membrane is 0.1-5 MPa and the filtration temperature is 10-80°C.

[0014] More preferably, the filtration pressure of the ultrafiltration membrane or nanofiltration membrane is 1 to 2 MPa, and the filtration temperature is 40 to 60°C.

[0015] Additionally, the material concentrator is connected to an online solids content / pH monitor.

[0016] Further, the separation unit is selected from an electrodialysis device and an ion exchange resin device.

[0017] Preferably, the separation unit is an electrodialysis device, and the voltage for separation is controlled to be 100 to 500 V and the current to be 2 to 10 A.

[0018] More preferably, the electrodialysis device is controlled so that the voltage for separation is 100 to 200 V and the current is 2 to 2.5 A.

[0019] In a second aspect, the present application provides a method for producing a salt-free amino acid surfactant by continuous flow using the above-mentioned production system, comprising: Step S1 of feeding an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment liquid into an amidation reaction module including at least one reactor unit to carry out an amidation reaction, and discharging an amidation product from the amidation reaction module; Step S2: conveying the amidation product into a post-treatment module, separating and concentrating the product through a discharge path A of the post-treatment module, discharging the finished product into a finished product tank, and discharging the mother liquor through a discharge path B of the post-treatment module; Step S3 of transporting the mother liquor into a mother liquor separation module including at least one separation unit, separating and discharging a mother liquor treatment liquid and a separated salt in the mother liquor separation module, and transporting the mother liquor treatment liquid to the amidation reaction module in step S1 for reuse; The present invention provides a method of manufacturing the same.

[0020] Furthermore, in step S1, the amino acid salt is one or a combination of two or more of sarcosine salt, glutamate salt, alanine salt, glycine salt, aspartate salt, serine salt, taurine salt, and methyl taurine salt.

[0021] Preferably, the amino acid salt is any one or a combination of two or more of sodium sarcosine, potassium glycine, sodium alanine, sodium glutamate, sodium methyl taurate, and sodium taurate.

[0022] Furthermore, in step S1, the acid chloride is an alkyl acid chloride having 8 to 21 carbon atoms or an alkenyl acid chloride having 8 to 21 carbon atoms.

[0023] Preferably, the acid chloride is any one or a combination of two or more of octanoic acid chloride, isooctanoic acid chloride, nonanoic acid chloride, isononanoic acid chloride, decanoic acid chloride, isodecanoic acid chloride, undecanoic acid chloride, dodecanoic acid chloride, tridecanoic acid chloride, tetradecanoic acid chloride, pentadecanoic acid chloride, hexadecanoic acid chloride, heptadecanoic acid chloride, octadecanoic acid chloride, nonadecanoic acid chloride, and eicosanoic acid chloride.

[0024] More preferably, the acid chloride is any one of dodecanoic acid chloride, coconut oil fatty acid chloride and lauric acid chloride.

[0025] Furthermore, in step S1, the liquid alkali is a sodium hydroxide solution or a potassium hydroxide solution.

[0026] Furthermore, in step S1, the mass content of the amino acid salt is 5% to 50%.

[0027] Preferably, the mass content of the amino acid salt is 25% to 35%.

[0028] Furthermore, in step S1, the flow rates of the amino acid salt and the mother liquor treatment solution are 0.04 to 100 kg / min.

[0029] Furthermore, in step S1, the flow rate of the acid chloride is 0.01 to 25 kg / min.

[0030] Furthermore, in step S1, the flow rate of the liquid alkali is 0.005 to 20 kg / min.

[0031] Furthermore, in step S1, the time for which the amino acid salt, the treated mother liquor, the acid chloride and the liquid alkali react and reside in the amidation reaction module is 180 to 360 s.

[0032] Preferably, the time for which the amino acid salt, the treated mother liquor, the acid chloride and the liquid alkali react and reside in the amidation reaction module is 190 to 230 seconds.

[0033] Compared with the prior art, the present application provides a production system and manufacturing method for producing salt-free amino acid surfactants by continuous flow, which has the following beneficial effects:

[0034] According to the present application, salt-free amino acid surfactants can be produced in a fully continuous flow, and the process is simple and efficient to operate, does not discharge waste acid, and the produced amino acid surfactant products have a low free acid index, are salt-free and have stable quality, are easy to produce on a large scale, greatly reduce production costs, and realize a green, environmentally friendly production process without discharging waste acid water. [Brief description of the drawings]

[0035] In order to more clearly describe the technical means in the embodiments of the present application or the prior art, the following briefly describes the drawings used in the description of the embodiments or the prior art. However, the drawings in the following description are only some of the embodiments of the present application, and those skilled in the art can obtain other drawings from these drawings without any creative effort. [Figure 1] FIG. 1 is a schematic diagram of a production system of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] The technical solutions of the present application will be described below clearly and completely, but it is clear that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments that a person skilled in the art can obtain without creative labor belong to the scope of protection of this application.

[0037] As shown in FIG. 1, the production system for producing salt-free amino acid surfactants by continuous flow according to the present application includes: an amidation reaction module configured to perform an amidation reaction, the amidation reaction module including at least one reactor unit having an input port configured to input an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment liquid, and an output port configured to output an amidation product; a post-treatment module, the input port of which is connected to the discharge port of the reactor unit, the amidation product is conveyed into the post-treatment module for separation and concentration treatment, the discharge line A of the post-treatment module is connected to the finished product tank, and the discharge line B of the post-treatment module discharges the mother liquor; a mother liquor separation module including at least one separation unit, in which an inlet port of the separation unit is connected to an outlet B of the post-treatment module, an outlet port of the separation unit discharges the separated salt, and a reflux port of the separation unit is connected to an inlet port of the reactor unit, and the mother liquor separation module discharges the mother liquor treated liquid and the separated salt after the mother liquor is treated in the separation unit.

[0038] Here, the reactor unit is equipped with two reactors, a microchannel reactor and a tubular reactor. The amidation reaction module includes a temperature section T1 corresponding to the microchannel reactor and a temperature section T2 corresponding to the tubular reactor, and the temperature ranges of the temperature sections T1 and T2 are 0-90°C. During the amidation reaction, the raw material first enters the microchannel reactor and then the tubular reactor.

[0039] The post-treatment module includes a membrane separator and a material concentrator, and an online solid content / PH monitor is connected to the material concentrator to facilitate online monitoring of desalination. The membrane separator is selected from any one or a combination of two or more of a microfiltration membrane, an ultrafiltration membrane, and a nanofiltration membrane. The material concentrator is selected from any one or a combination of two or more of a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane, and a RO membrane (reverse osmosis membrane). In some specific embodiments, the membrane separator and the material concentrator are selected from an ultrafiltration membrane and a nanofiltration membrane, and the filtration pressure of the ultrafiltration membrane or the nanofiltration membrane is 0.1-5 MPa, and the filtration temperature is 10-80°C.

[0040] The separation unit is selected from an electrodialysis device and an ion exchange resin device. In some specific embodiments, the separation unit is preferably an electrodialysis device, and the voltage of the separation is controlled to be 100-500V and the current is controlled to be 2-10A.

[0041] The present application further provides a method for producing a salt-free amino acid surfactant by continuous flow using the above-mentioned production system, and this production method includes the following steps S1 to S3. In step S1, an amino acid salt, an acid chloride, a liquid alkali and a mother liquor treatment liquid are respectively introduced into an amidation reaction module including at least one reactor unit to carry out an amidation reaction, and an amidation product is discharged from the amidation reaction module. In step S2, the amidation product is transported into the post-treatment module, separated and concentrated in the discharge path A of the post-treatment module, the finished product is discharged into the finished product tank, and the mother liquor is separated and discharged in the discharge path B of the post-treatment module. In step S3, the mother liquor is transported into a mother liquor separation module including at least one separation unit, where the mother liquor treatment liquid and the separated salt are separated and discharged, and the mother liquor treatment liquid is transported as a reflux into the amidation reaction module in step S1 for reuse.

[0042] Here, in step S1, the amino acid salt is one or a combination of two or more of sarcosine salt, glutamate salt, alanine salt, glycine salt, aspartate salt, serine salt, taurine salt, and methyl taurine salt. Preferably, the amino acid salt is one or a combination of two or more of sodium sarcosine, potassium glycine, sodium alanine, sodium glutamate, sodium methyl taurine, and sodium taurine.

[0043] In step S1, the acid chloride is an alkyl acid chloride having 8 to 21 carbon atoms or an alkenyl acid chloride having 8 to 21 carbon atoms. Preferably, the acid chloride is any one of octanoic acid chloride, isooctanoic acid chloride, nonanoic acid chloride, isononanoic acid chloride, decanoic acid chloride, isodecanoic acid chloride, undecanoic acid chloride, dodecanoic acid chloride, tridecanoic acid chloride, tetradecanoic acid chloride, pentadecanoic acid chloride, hexadecanoic acid chloride, heptadecanoic acid chloride, octadecanoic acid chloride, nonadecanoic acid chloride and eicosanoic acid chloride, or a combination of two or more thereof. More preferably, the acid chloride is any one of dodecanoic acid chloride, coconut oil fatty acid chloride and lauric acid chloride.

[0044] In step S1, the liquid alkali is a sodium hydroxide solution or a potassium hydroxide solution.

[0045] In step S1, the mass content of the amino acid salt is 5%-50%, the flow rates of the amino acid salt and the mother liquor treatment liquid are 0.04-100 kg / min, the flow rate of the acid chloride is 0.01-25 kg / min, and the flow rate of the liquid alkali is 0.005-20 kg / min. The reaction and residence time of the amino acid salt, the mother liquor treatment liquid, the acid chloride, and the liquid alkali in the amidation reaction module is 180-360 s. The control of the input of these four raw materials can be appropriately adjusted or expanded according to the actual production scale.

[0046] The present application will now be described in more detail with reference to FIG.

[0047] All of the various raw materials used in the following examples are commercially available.

[0048] Example 1 This example provides a process for producing a salt-free amino acid surfactant by continuous flow, and the process is specifically as follows. The raw materials, sodium sarcosine (mass content 35%), dodecanoic acid chloride, liquid alkali (sodium hydroxide solution) and mother liquor treatment liquid, were respectively fed into the amidation reaction module via a constant flow pump to carry out the amidation reaction. Here, the temperature section T1 corresponding to the microchannel reactor was set to 2-5°C, and the temperature section T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the raw materials fed were set as follows. The flow rate of sodium sarcosine and mother liquor treatment liquid was 40.2g / min, the flow rate of dodecanoic acid chloride was 12.3g / min, and the flow rate of liquid alkali (sodium hydroxide solution, mass content 30%) was 7.3g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then entered the tubular reactor, and the residence time was controlled to 200s, and reacted completely. After that, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a substance concentrator, and the substance concentrator was connected to an online solid content / PH monitor to facilitate online monitoring of desalination. Here, the membrane separator and the substance concentrator were selected from ultrafiltration membrane and nanofiltration membrane, and the filtration pressure was controlled to 1MPa and the filtration temperature to 60℃, so that the product sodium lauroyl sarcosine was obtained in the discharge path A and transported to the finished product tank, and the mother liquor was separated and discharged in the discharge path B and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis device. The separation voltage was controlled to 100 V and the current to 2 A to perform mother liquor separation, and the mother liquor treatment liquid and separated salt were discharged. The mother liquor treatment liquid was transported by reflux to the amidation reaction module for reuse. For the sodium lauroyl sarcosinate produced in this example, the product indicators were free acid <1%, sodium chloride <0.1%.

[0049] Example 2 This example provides a process for producing a salt-free amino acid surfactant by continuous flow, and the process is specifically as follows. The raw materials, potassium glycine (mass content 25%), dodecanoic acid chloride, liquid alkali (potassium hydroxide solution) and mother liquor treatment liquid, were respectively fed into the amidation reaction module via a constant flow pump to carry out the amidation reaction. Here, the temperature section T1 corresponding to the microchannel reactor was set to 5-15°C, and the temperature section T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the raw materials fed were set as follows. The flow rate of potassium glycine and mother liquor treatment liquid was 49.2g / min, the flow rate of dodecanoic acid chloride was 12.3g / min, and the flow rate of liquid alkali (potassium hydroxide solution, mass content 30%) was 7.3g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then entered the tubular reactor, and the residence time was controlled to 220s, and reacted completely. After that, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrator, and the material concentrator was connected to an online solid content / PH monitor to facilitate online monitoring of desalination. Here, the membrane separator and material concentrator were selected from ultrafiltration membrane and nanofiltration membrane, and the filtration pressure was controlled to 1.5MPa and the filtration temperature to 50℃, so that the product potassium lauroyl glycine was obtained in discharge path A and transported to the finished product tank, and the mother liquor was separated and discharged in discharge path B and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis device. The separation voltage was controlled to 200 V and the current to 2 A to perform mother liquor separation, and the mother liquor treatment liquid and separated salt were discharged. The mother liquor treatment liquid was transported by reflux to the amidation reaction module for reuse. For the potassium lauroyl glycinate produced in this example, the product indicators were free acid <1.8% and sodium chloride <0.2%.

[0050] Example 3 This example provides a process for producing a salt-free amino acid surfactant by continuous flow, and the process is specifically as follows. The raw materials, sodium alanine (mass content 30%), coconut oil fatty acid chloride, liquid alkali (sodium hydroxide solution) and mother liquor treatment liquid, were respectively fed into the amidation reaction module via a constant flow pump to carry out the amidation reaction. Here, the temperature section T1 corresponding to the microchannel reactor was set to 0-5°C, and the temperature section T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the raw materials fed were set as follows. The flow rate of sodium alanine and mother liquor treatment liquid was 46.2g / min, the flow rate of coconut oil fatty acid chloride was 13.3g / min, and the flow rate of liquid alkali (sodium hydroxide solution, mass content 30%) was 7.9g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then entered the tubular reactor, and the residence time was controlled to 190s, and reacted completely. After that, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a substance concentrator, and the substance concentrator was connected to an online solid content / PH monitor to facilitate online monitoring of desalination. Here, the membrane separator and the substance concentrator were selected from ultrafiltration membrane and nanofiltration membrane, and the filtration pressure was controlled to 1MPa and the filtration temperature to 40℃, so that the product, coconut oil fatty acid acylalanine sodium, was obtained in discharge path A and transported to the finished product tank, and the mother liquor was separated and discharged in discharge path B and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis device. The separation voltage was controlled to 100 V and the current to 2 A to perform mother liquor separation, and the mother liquor treatment liquid and separated salt were discharged. The mother liquor treatment liquid was transported by reflux to the amidation reaction module for reuse. For the sodium coconut acylalanine produced in this example, the product indicators were free acid <1% and sodium chloride <0.2%.

[0051] Example 4 This example provides a process for producing a salt-free amino acid surfactant by continuous flow, and the process is specifically as follows. The raw materials, sodium glutamate (mass content 30%), coconut oil fatty acid chloride, liquid alkali (sodium hydroxide solution) and mother liquor treatment liquid, were each fed into the amidation reaction module via a constant flow pump to carry out the amidation reaction. Here, the temperature section T1 corresponding to the microchannel reactor was set to 0-10°C, and the temperature section T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the raw materials fed were set as follows. The flow rate of sodium glutamate and mother liquor treatment liquid was 56g / min, the flow rate of coconut oil fatty acid chloride was 13g / min, and the flow rate of liquid alkali (sodium hydroxide solution, mass content 30%) was 8g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor and then the tubular reactor, the residence time was controlled to 230s, and the reaction was complete. After that, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrator, and the material concentrator was connected to an online solid content / PH monitor to facilitate online monitoring of desalination. Here, the membrane separator and material concentrator were selected from ultrafiltration membrane and nanofiltration membrane, and the filtration pressure was controlled to 1.5MPa and the filtration temperature to 60℃, so that the product, sodium coconut acyl glutamate, was obtained in discharge path A and transported to the finished product tank, and the mother liquor was separated and discharged in discharge path B and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis device. The separation voltage was controlled to 100 V and the current to 2 A to perform mother liquor separation, and the mother liquor treatment liquid and separated salt were discharged. The mother liquor treatment liquid was transported by reflux to the amidation reaction module for reuse. For the sodium cocoyl glutamate produced in this example, the product indicators were free acid <1.8%, sodium chloride <0.2%.

[0052] Example 5 This example provides a process for producing a salt-free amino acid surfactant by continuous flow, and the process is specifically as follows. The raw materials, sodium glutamate (mass content 30%), lauric chloride, liquid alkali (sodium hydroxide solution) and mother liquor treatment liquid, were each fed into the amidation reaction module via a constant flow pump to carry out the amidation reaction. Here, the temperature section T1 corresponding to the microchannel reactor was set to 0-10°C, and the temperature section T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the raw materials fed were set as follows. The flow rate of sodium glutamate and mother liquor treatment liquid was 56g / min, the flow rate of lauric chloride was 1.3g / min, and the flow rate of liquid alkali (sodium hydroxide solution, mass content 30%) was 7.3g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor and then the tubular reactor, the residence time was controlled to 230s, and the reaction was complete. After that, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a substance concentrator, and the substance concentrator was connected to an online solid content / PH monitor to facilitate online monitoring of desalination. Here, the membrane separator and the substance concentrator were selected from ultrafiltration membrane and nanofiltration membrane, and the filtration pressure was controlled to 1.5MPa and the filtration temperature to 60℃, so that the product sodium lauroyl glutamate was obtained in discharge path A and transported to the finished product tank, and the mother liquor was separated and discharged in discharge path B and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis device. The separation voltage was controlled to 100 V and the current to 2 A to perform mother liquor separation, and the mother liquor treatment liquid and separated salt were discharged. The mother liquor treatment liquid was transported by reflux to the amidation reaction module for reuse. For the sodium lauroyl glutamate produced in this example, the product indicators were free acid <1.8%, sodium chloride <0.2%.

[0053] Example 6 This example provides a process for producing a salt-free amino acid surfactant by continuous flow, and the process is specifically as follows. The raw materials, sodium methyl taurate (mass content 30%), lauric acid chloride, liquid alkali (sodium hydroxide solution) and mother liquor treatment liquid, were each fed into the amidation reaction module via a constant flow pump to carry out the amidation reaction. Here, the temperature section T1 corresponding to the microchannel reactor was set to 0-10°C, and the temperature section T2 corresponding to the tubular reactor was set to 70-85°C. The flow rates of the raw materials fed were set as follows. The flow rate of sodium methyl taurate and mother liquor treatment liquid was 60g / min, the flow rate of lauric acid chloride was 12.5g / min, and the flow rate of liquid alkali (sodium hydroxide solution, mass content 30%) was 7.8g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then entered the tubular reactor, and the residence time was controlled to 210s, and reacted completely. After that, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a substance concentrator, and the substance concentrator was connected to an online solid content / PH monitor to facilitate online monitoring of desalination. Here, the membrane separator and the substance concentrator were selected from ultrafiltration membrane and nanofiltration membrane, and the filtration pressure was controlled to 2MPa and the filtration temperature to 60℃, so that the product sodium lauroyl methyl taurate was obtained in discharge path A and transported to the finished product tank, and the mother liquor was separated and discharged in discharge path B and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis device. The separation voltage was controlled to 200 V and the current to 2 A to perform mother liquor separation, and the mother liquor treatment liquid and separated salt were discharged. The mother liquor treatment liquid was transported by reflux to the amidation reaction module for reuse. For the sodium lauroyl methyl taurate produced in this example, the product indicators were free acid <1.8%, sodium chloride <0.2%.

[0054] Example 7 This example provides a process for producing a salt-free amino acid surfactant by continuous flow, and the process is specifically as follows. The raw materials, a mixture of sodium methyl taurate and sodium taurate (mass content 30%), coconut oil fatty acid chloride, liquid alkali (sodium hydroxide solution) and mother liquor treatment liquid, were respectively fed into the amidation reaction module via a constant flow pump to carry out the amidation reaction. Here, the temperature section T1 corresponding to the microchannel reactor was set to 0-10 ° C, and the temperature section T2 corresponding to the tubular reactor was set to 70-85 ° C. The flow rates of the raw materials fed were set as follows. The flow rate of the mixture of sodium methyl taurate and sodium taurate and the mother liquor treatment liquid was 60 g / min, the flow rate of the coconut oil fatty acid chloride was 13.5 g / min, and the flow rate of the liquid alkali (sodium hydroxide solution, mass content 30%) was 7.5 g / min. In the amidation reaction module, the raw materials first entered the microchannel reactor, then entered the tubular reactor, and the residence time was controlled to 200 s, and reacted completely. After that, the amidation product was discharged from the amidation reaction module and entered the post-treatment module for post-treatment. The post-treatment module was equipped with a membrane separator and a material concentrator, and the material concentrator was connected to an online solid content / PH monitor to facilitate online monitoring of desalination. Here, the membrane separator and material concentrator were selected from ultrafiltration membrane and nanofiltration membrane, and the filtration pressure was controlled to 2MPa and the filtration temperature to 60℃, so that the product, sodium coconut oil fatty acid acyl methyl taurate / sodium coconut oil fatty acid acyltaurate, was obtained in discharge path A and transported to the finished product tank, and the mother liquor was separated and discharged in discharge path B and entered the mother liquor separation module. The mother liquor separation module included at least one separation unit, which was specifically an electrodialysis device. The separation voltage was controlled to 200 V and the current to 2.5 A to perform mother liquor separation, and the mother liquor treatment liquid and separated salt were discharged. The mother liquor treatment liquid was transported by reflux to the amidation reaction module for reuse. For the sodium coconut oil fatty acid acyl methyl taurate / sodium coconut oil fatty acid acyltaurate produced in this example, the product indicators were free acid <1% and sodium chloride <0.2%.

[0055] The above description is merely a preferred embodiment of the present application, and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0056] It should be noted that, although the present specification has been described based on the embodiments, each embodiment does not include only one independent technical solution. Such description in the present specification is merely for the purpose of clarification, and those skilled in the art should take the description as a whole, and should understand that the technical solutions in each embodiment may be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. 1. A production system for producing salt-free amino acid surfactants by continuous flow, comprising: an amidation reaction module configured to perform an amidation reaction, the amidation reaction module including at least one reactor unit having an input port configured to input an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment liquid, and an output port configured to output an amidation product; a post-treatment module, the input port of the post-treatment module is connected to the discharge port of the reactor unit, the amidation product is conveyed into the post-treatment module for separation and concentration treatment, the discharge line A of the post-treatment module is connected to the finished product tank, and the discharge line B of the post-treatment module discharges the mother liquor; a mother liquor separation module including at least one separation unit, the inlet port of the separation unit being connected to the outlet B of the post-treatment module, the outlet port of the separation unit being for discharging the separated salt, and the reflux port of the separation unit being connected to the inlet port of the reactor unit, the mother liquor being treated in the separation unit and then discharging the mother liquor treated liquid and the separated salt; A production system comprising:

2. 2. The production system according to claim 1, wherein the reactor unit is selected from any one or a combination of two or more of a microchannel reactor, a series coil pipe reactor, and a tubular reactor.

3. 2. The production system according to claim 1, wherein the amidation reaction module includes temperature zones T1 and T2, and the temperature ranges of the temperature zones T1 and T2 are 0 to 90°C.

4. The production system according to claim 1, characterized in that the post-treatment module comprises a membrane separation device and a substance concentration device, the membrane separation device being selected from any one or a combination of two or more of a microfiltration membrane, an ultrafiltration membrane and a nanofiltration membrane, and the substance concentration device being selected from any one or a combination of two or more of a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane and an RO membrane (reverse osmosis membrane).

5. 5. The production system of claim 4, further comprising an online solids content / pH monitor connected to the material concentrator.

6. 2. The production system according to claim 1, wherein the separation unit is selected from an electrodialysis device and an ion exchange resin device.

7. A method for producing a salt-free amino acid surfactant by continuous flow using the production system according to any one of claims 1 to 6, comprising the steps of: Step S1 of feeding an amino acid salt, an acid chloride, a liquid alkali, and a mother liquor treatment liquid into an amidation reaction module including at least one reactor unit to carry out an amidation reaction, and discharging an amidation product from the amidation reaction module; Step S2: conveying the amidation product into a post-treatment module, separating and concentrating the product through a discharge path A of the post-treatment module, discharging the finished product into a finished product tank, and separating and discharging the mother liquor through a discharge path B of the post-treatment module; Step S3 of transporting the mother liquor into a mother liquor separation module including at least one separation unit, separating and discharging a mother liquor treatment liquid and a separated salt in the mother liquor separation module, and transporting the mother liquor treatment liquid to the amidation reaction module in step S1 as a reflux for reuse; A manufacturing method comprising the steps of:

8. 8. The method according to claim 7, wherein in step S1, the amino acid salt is one or a combination of two or more of a sarcosine salt, a glutamate salt, an alanine salt, a glycine salt, an aspartate salt, a serine salt, a taurine salt, and a methyl taurine salt, the acid chloride is an alkyl acid chloride having 8 to 21 carbon atoms or an alkenyl acid chloride having 8 to 21 carbon atoms, and the liquid alkali is a sodium hydroxide solution or a potassium hydroxide solution.

9. The method according to claim 7, wherein in step S1, the mass content of the amino acid salt is 5% to 50%.

10. 8. The production method according to claim 7, wherein in step S1, the flow rates of the amino acid salt and the mother liquor processing solution are 0.04 to 100 kg / min, the flow rate of the acid chloride is 0.01 to 25 kg / min, the flow rate of the liquid alkali is 0.005 to 20 kg / min, and the time for which the amino acid salt, the mother liquor processing solution, the acid chloride and the liquid alkali react and reside in the amidation reaction module is 180 to 360 s.

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