Continuous energy-saving production system of fatty acid amide propyl tertiary amine

Abstract

The invention discloses a continuous energy-saving production system of fatty acid amide propyl tertiary amine, which adopts a three-kettle linkage process of a dehydration kettle, a reaction kettle and a cooling kettle, and is provided with a special cooling kettle, so that the cooling time of materials after reaction can be greatly shortened, and the utilization rate of the reaction kettle can be improved, thereby effectively shortening the whole production cycle. The production continuity of fatty acid amide propyl tertiary amine (PKO) is ensured, and the overall production efficiency is improved. According to the method, the N, N-dimethyl-1, 3-propane diamine solution which is not completely reacted is collected into the recovery tank and then is introduced into the dehydration kettle again to react with fatty acid, so that the process is beneficial to saving the production cost, the wastewater can be directly discharged in a manner of removing the wastewater under reduced pressure, the problem of ammonia nitrogen discharge is solved, and the environmental pollution is reduced.

Description

Technical Field

[0001] The invention belongs to the field of production technology of surfactants, and specifically relates to a continuous energy-saving production system of fatty amide propyl tertiary amine. Background Art

[0002] Fatty amide propyl tertiary amine (PKO) is a fine chemical intermediate used to synthesize cationic and amphoteric surfactants. As a conditioning agent and antistatic agent, PKO is widely used in personal care products such as shampoo and conditioner to enhance the feel and functionality of the products. In cleaning products such as detergents, it can effectively remove dirt and grease, significantly enhancing the cleaning effect. In addition, in oilfield chemicals, PKO can be used to improve fluid properties and corrosion resistance.

[0003] PKO is prepared by the reaction of fatty acids and N,N-dimethyl-1,3-propylenediamine, of which N,N-dimethyl-1,3-propylenediamine is highly corrosive and may cause irritation when in contact with the skin or eyes. In industrial production, in order to improve the reaction conversion rate and promote the reaction in the positive direction, it is usually necessary to increase the feed ratio of fatty acids and N,N-dimethyl-1,3-propylenediamine and increase the amidation reaction temperature. The production of this type of product currently has the following main problems: (1) The residual N,N-dimethyl-1,3-propylenediamine in the reaction exceeds the standard, and the irritating amine odor it carries affects the use effect of the end product. (2) If the removed N,N-dimethyl-1,3-propylenediamine wastewater is directly discharged without treatment, it will not only pollute the environment, but also lead to waste of raw materials. (3) The high temperature required for the amidation reaction leads to high energy consumption and long product cooling time, which in turn increases the production cost of PKO and reduces production efficiency. Summary of the invention

[0004] In view of the above problems, the present invention provides a continuous energy-saving production system for fatty amide propyl tertiary amine. By adopting a three-kettle linkage process of a dehydration kettle, a reactor and a cooling kettle, and by setting a special cooling kettle, the cooling time of the material after the reaction can be greatly shortened, and the utilization rate of the reactor can be improved, thereby effectively shortening the entire production cycle, ensuring the continuity of PKO production, and improving the overall production efficiency. The incompletely reacted N, N-dimethyl-1, 3-propylenediamine solution is collected in a recovery tank and then reintroduced into the dehydration kettle to react with fatty acids. This process not only helps to save production costs, but also can directly discharge wastewater by removing wastewater under reduced pressure, solves the problem of ammonia nitrogen emissions, and reduces environmental pollution. The hot water obtained by heat exchange of cooling water through a heat exchanger connected to the cooling kettle can be used to heat the fatty acid storage tank, realizing the effective reuse of energy and improving energy utilization. In addition, a small amount of water is added to the reactor to form mixed steam with N, N-dimethyl-1, 3-propylenediamine under high temperature conditions, which helps to remove the amine taste in the product and improve the quality of the product.

[0005] The present invention provides a continuous energy-saving production system of fatty amide propyl tertiary amine, which comprises a fatty acid tank for storing fatty acids, a propylene diamine tank for storing N,N-dimethyl-1,3-propylene diamine, and a reactor for carrying out amidation reaction of fatty acids and N,N-dimethyl-1,3-propylene diamine; and further comprises: an amine recovery tank and a heat exchanger, wherein the mixed steam of N,N-dimethyl-1,3-propylene diamine and water escaping during the reaction of the reactor is liquefied by the heat exchanger to form N,N-dimethyl-1,3-propylene diamine. The recovered propylene diamine liquid enters the amine recovery tank; the dehydration kettle, the N, N-dimethyl-1, 3-propylene diamine recovered liquid and the fatty acid in the fatty acid tank are mixed and dehydrated in the dehydration kettle and then enter the reactor; the fatty acid in the dehydration kettle will lock the propylene diamine in the recovered propylene diamine liquid, and avoid the azeotropic reaction of amine and water during the dehydration process as much as possible. In addition, the establishment of the dehydration kettle can ensure continuous production. While the reactor is reacting, the dehydration kettle can prepare the amount of fatty acid and part of propylene diamine, which will be passed to the reactor for subsequent reaction. The heat recovery device recovers the heat in the reaction product of the reactor, and the recovered heat is used to heat the fatty acid in the fatty acid tank.

[0006] Furthermore, the heat recovery device includes a heat exchanger and a hot water tank. The reaction product is transferred from the reactor to the cooling kettle via the heat exchanger. The heat exchanger heats the hot water tank for heating the fatty acids in the fatty acid tank.

[0007] Furthermore, the reaction product is discharged after being cooled in a cooling kettle to a temperature not higher than 80°C.

[0008] Furthermore, the molar ratio of fatty acid to N,N-dimethyl-1,3-propylenediamine in the reactor is 1:(1.0-1.5).

[0009] Furthermore, the amidation reaction temperature is 120-200° C., and the reaction time is 3-8 h.

[0010] The method adopts a three-kettle linkage process of a dehydration kettle, a reaction kettle and a cooling kettle, which greatly shortens the cooling time, increases the utilization rate of the reaction kettle, improves production efficiency, and ensures continuous PKO production.

[0011] The unreacted N,N-dimethyl-1,3-propylenediamine solution in the production process can be collected into a recovery tank and passed into a dehydration kettle to react with fatty acids. The wastewater removed under reduced pressure can be directly discharged, which effectively solves the problem of ammonia nitrogen emissions while saving production costs.

[0012] The beneficial effects of the present invention are: (1) The three-reactor linkage method for producing PKO shortens the cooling time by 2-3 hours compared with the original method. At the same time, the spare reactor can be used for the synthesis of the next batch of materials, which greatly shortens the production cycle and improves production efficiency.

[0013] (2) The cooling water is heat exchanged through a heat exchanger connected to the cooling kettle, and the hot water is used to heat the fatty acid storage tank to 60°C, thereby achieving effective energy utilization and saving approximately 334.4 MJ of energy.

[0014] (3) Recycle and utilize N,N-dimethyl-1,3-propylenediamine wastewater to save energy, reduce emissions, and increase economic benefits; (4) The N,N-dimethyl-1,3-propylenediamine content in the wastewater distilled by the method of the present invention is less than 0.3% (amine value <1.65 mg KOH / g), and COD <1000 mg / L, meeting the COD value requirement for biochemical treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the device for continuous energy-saving production of fatty amide propyl tertiary amine. DETAILED DESCRIPTION

[0016] The following examples are used to further illustrate the present invention, and their purpose is to illustrate the present invention and should not be construed as limiting the scope of the present invention. Unless otherwise specified, all parts by weight and weight percentages are used below.

[0017] The raw materials used in the present invention, unless otherwise specified, are conventional commercially available products; the methods used in the present invention, unless otherwise specified, are conventional methods in the art.

[0018] The qualified standard of the PKO amine value of the present invention is determined according to the molecular weight of PKO, amine value = 56100 / PKO molecular weight, and the standard is the calculated amine value ± 5.

[0019] The embodiments of the present invention are further described below with reference to a plurality of embodiments.

[0020] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0021] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0022] Reference Figure 1The present invention provides a continuous energy-saving production system of fatty amide propyl tertiary amine, which comprises a fatty acid tank for storing fatty acids, a propylene diamine tank for storing N, N-dimethyl-1, 3-propylene diamine, and a reactor for performing amidation reaction of fatty acids and N, N-dimethyl-1, 3-propylene diamine; and The amine recovery tank and the heat exchanger are used to realize the recovery of amines, wherein the mixed steam of N,N-dimethyl-1,3-propylenediamine and water escaping from the reaction kettle during the reaction process is liquefied by the heat exchanger to form N,N-dimethyl-1,3-propylenediamine recovery liquid, which enters the amine recovery tank; Dehydration kettle, the N,N-dimethyl-1,3-propylenediamine recovery liquid and the fatty acid in the fatty acid tank are mixed and dehydrated in the dehydration kettle and then enter the reactor; the fatty acid in the dehydration kettle will lock the propylenediamine in the propylenediamine recovery liquid, and avoid the azeotropic reaction of amine and water during the dehydration process as much as possible. In addition, the establishment of the dehydration kettle can ensure continuous production. While the reactor is reacting, the dehydration kettle can prepare the amount of fatty acid and part of propylenediamine, which will be passed to the reactor for subsequent reaction.

[0023] The heat recovery device recovers the heat from the reaction product of the reactor, and the recovered heat is used to heat the fatty acids in the fatty acid tank. In the figure, the heat recovery device includes a heat exchanger and a hot water tank. The reaction product is transferred from the reactor to the cooling kettle through the heat exchanger. The heat exchanger heats the hot water tank for heating the fatty acids in the fatty acid tank.

[0024] Example 1 (1) After being heated in the storage tank, 4600 kg of lauric acid and 600 kg of N,N-dimethyl-1,3-propylenediamine recovered liquid are passed into the dehydration kettle, and a mixed liquid is obtained after decompression dehydration. The amine value of the removed wastewater is 0.9 mg KOH / g and can be discharged directly; (2) The mixed solution was transferred into a reactor and 2000 kg of pure N,N-dimethyl-1,3-propylenediamine was added dropwise. The total molar ratio of fatty acid to N,N-dimethyl-1,3-propylenediamine was 1:1.0. The temperature was raised to 200 °C under nitrogen protection and the reaction was carried out for 3 h. After the acid value was controlled to ≤6 mg KOH / g (4.6 mg KOH / g), a trace amount of deionized water was slowly introduced and vacuum was drawn to remove the amine. (3) The mixed steam of water and amine is condensed and enters the recovery tank to obtain amine recovery liquid for feeding the next batch; (4) When the PKO amine value reaches 190-199 mg KOH / g, it is cooled by a heat exchanger and enters a cooling kettle. The material is discharged when the temperature is less than 80°C.

[0025] Example 2 (1) After heating in a storage tank, 6135 kg of stearic acid and 600 kg of N,N-dimethyl-1,3-propylenediamine recovery liquid are passed into a dehydration kettle to obtain a mixed liquid after decompression dehydration. The amine value of the removed wastewater is 1.1 mg KOH / g and can be directly discharged. The stearic acid used is industrial stearic acid (1840) with a molecular weight of 267, which is composed of 60% palmitic acid and 40% stearic acid.

[0026] (2) The mixed solution was transferred into a reactor and 3170 kg of pure N,N-dimethyl-1,3-propylenediamine was added dropwise. The total molar ratio of stearic acid to N,N-dimethyl-1,3-propylenediamine was 1:1.5. The temperature was raised to 200 °C under nitrogen protection and the reaction was carried out for 3 h. After the acid value was controlled to ≤6 mg KOH / g (3.1 mg KOH / g), a trace amount of deionized water was slowly introduced and vacuum was drawn to remove the amine. (3) The mixed steam of water and amine is condensed and enters the recovery tank to obtain amine recovery liquid for feeding the next batch; (4) When the PKO amine value reaches 155-166 mg KOH / g, it is cooled through a heat exchanger and enters a cooling kettle. The material is discharged when the temperature is less than 80 °C.

[0027] Example 3 (1) After being heated in the storage tank, 5894 kg of palmitic acid and 600 kg of N,N-dimethyl-1,3-propylenediamine recovered liquid are passed into the dehydration kettle, and a mixed liquid is obtained after decompression dehydration. The amine value of the removed wastewater is 1.2 mg KOH / g, which can be directly discharged; (2) The mixed solution was transferred into a reactor and 3170 kg of pure N,N-dimethyl-1,3-propylenediamine was added dropwise. The total molar ratio of palmitic acid to N,N-dimethyl-1,3-propylenediamine was 1:1.5. The mixture was heated to 120 °C under nitrogen protection and reacted for 8 h. After the acid value was ≤6 mg KOH / g (3.6 mg KOH / g), a trace amount of deionized water was slowly introduced and vacuum was applied to remove the amine. (3) The mixed steam of water and amine is condensed and enters the recovery tank to obtain amine recovery liquid for feeding the next batch; (4) When the PKO amine value reaches 160-170 mg KOH / g, it is cooled by a heat exchanger and enters a cooling kettle. The material is discharged when the temperature is less than 80°C.

[0028] The above embodiments describe in detail the structure, features and effects of the present invention. The above are only preferred embodiments of the present invention. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the scope covered by the specification, should be within the protection scope of the present invention.

Claims

1. A continuous energy-saving production system for fatty amide propyl tertiary amine, comprising a fatty acid tank for storing fatty acids, a propylene diamine tank for storing N, N-dimethyl-1, 3-propylene diamine, and a reactor for amidation reaction of fatty acids and N, N-dimethyl-1, 3-propylene diamine; characterized in that: Also includes: An amine recovery tank and a heat exchanger, wherein the mixed steam of N,N-dimethyl-1,3-propylenediamine and water escaping during the reaction of the reactor is liquefied by the heat exchanger to form N,N-dimethyl-1,3-propylenediamine recovery liquid, which enters the amine recovery tank; a dehydration kettle, wherein the N,N-dimethyl-1,3-propylenediamine recovery liquid and the fatty acid in the fatty acid tank are mixed and dehydrated in the dehydration kettle and then enter the reactor; and a heat recovery device, which recovers the heat in the reaction product of the reactor, and the recovered heat is used for heating the fatty acid in the fatty acid tank.

2. The system according to claim 1, characterized in that The heat recovery device comprises a heat exchanger and a hot water tank. The reaction product is transferred from the reactor to the cooling kettle via the heat exchanger. The heat exchanger heats the hot water tank for heating the fatty acid in the fatty acid tank.

3. The system according to claim 2, characterized in that The reaction product is discharged after the temperature is reduced to no higher than 80° C. in the cooling kettle.

4. The system according to claim 1, characterized in that The molar ratio of fatty acid to N,N-dimethyl-1,3-propylenediamine in the reactor is 1:(1.0-1.5).

5. The system according to claim 1, characterized in that The amidation reaction temperature is 120-200° C., and the reaction time is 3-8 h.

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