A production system for improving propylene glycol methyl ether conversion rate

Abstract

The utility model relates to propylene glycol methyl ether production technical field, concretely relates to a kind of production system of promoting propylene glycol methyl ether conversion rate, including propylene oxide feed pump, methanol feed pump, first steam jacketed reactor, secondary thermostatic reactor, tertiary thermostatic reactor and rectifying column, propylene oxide feed pump, first steam jacketed reactor, secondary thermostatic reactor and tertiary thermostatic reactor are sequentially connected by pipeline, methanol feed pump is connected with first steam jacketed reactor, secondary thermostatic reactor and tertiary thermostatic reactor respectively by pipeline, tertiary thermostatic reactor is connected with the middle part of dealcoholization tower by pipeline, the bottom of dealcoholization tower is connected with the middle part of rectifying column, rectifying column top is connected with condenser by pipeline, condenser is connected with propylene glycol methyl ether finished product tank by pipeline.The utility model process is simple, can effectively reduce the production amount of by-product, reduce the production amount of heavy tar, is favorable for reducing production cost, improves clean production level.

Description

Technical Field

[0001] This utility model relates to the field of propylene glycol methyl ether production technology, specifically to a production system for improving the conversion rate of propylene glycol methyl ether. Background Technology

[0002] Propylene glycol methyl ether is an important intermediate compound. Because it contains both hydrophobic functional groups (ether bonds) and hydrophilic groups (hydroxyl groups), it can dissolve lipophilic compounds and water-soluble substances. It is widely used in coating materials, paints, antifreeze, printing, leather dyeing, electronic chemicals and other fields.

[0003] Currently, the production of propylene glycol methyl ether mainly adopts the method of etherification of propylene oxide and methanol. This method is difficult to control in terms of reaction temperature and pressure, has many side reactions and byproducts, and is prone to forming heavy tar during distillation, resulting in a large amount of hazardous waste. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a production system for improving the conversion rate of propylene glycol methyl ether, thereby solving the issues of numerous byproducts and large amounts of hazardous waste generated in existing technologies.

[0005] To achieve the above objectives, this utility model provides a production system for improving the conversion rate of propylene glycol methyl ether, comprising a propylene oxide feed pump, a methanol feed pump, a primary steam jacket reactor, a secondary isothermal reactor, a tertiary isothermal reactor, a dealcoholization tower, and a distillation tower. The propylene oxide feed pump, the primary steam jacket reactor, the secondary isothermal reactor, and the tertiary isothermal reactor are connected sequentially via pipelines. The methanol feed pump is connected to the primary steam jacket reactor, the secondary isothermal reactor, and the tertiary isothermal reactor via pipelines. The reactor is connected to the middle of the dealcoholization column via a pipeline, and the bottom of the dealcoholization column is connected to the middle of the distillation column via a pipeline. Feed pump 1, feed pump 2, feed pump 3, and feed pump 4 are respectively installed on the pipelines between the primary steam jacket reactor and the secondary isothermal reactor, the secondary isothermal reactor and the tertiary isothermal reactor, the tertiary isothermal reactor and the dealcoholization column, and the dealcoholization column and the distillation column. The top of the distillation column is connected to a condenser via a pipeline, and the condenser is connected to a propylene glycol methyl ether finished product tank via a pipeline.

[0006] Furthermore, a circulating heating pipeline is connected between the bottom and lower part of the dealcoholization column and the distillation column. A reboiler is installed on the circulating heating pipeline, and the reboiler is connected to a steam inlet pipe and a steam outlet pipe.

[0007] Furthermore, the top of the dealcoholization tower is connected to a dealcoholization gas discharge pipe.

[0008] Furthermore, a heavy tar extraction pipe is connected to the bottom of the distillation column.

[0009] Furthermore, the primary steam jacket reactor, the secondary isothermal reactor, and the tertiary isothermal reactor are all filled with X-type molecular sieves.

[0010] Furthermore, the condenser is connected to a cooling water inlet pipe and a cooling water outlet pipe, respectively.

[0011] Furthermore, a pneumatic regulating valve is installed on the pipeline between the three-stage constant temperature reactor and the dealcoholization tower, and a pneumatic regulating valve is installed on the pipeline between the dealcoholization tower and the distillation tower.

[0012] Furthermore, flow regulating valves are installed on the pipeline between the propylene oxide feed pump and the primary steam jacket reactor, as well as on the pipelines between the methanol feed pump and the primary steam jacket reactor, the secondary isothermal reactor, and the tertiary isothermal reactor, respectively.

[0013] The beneficial effects of this utility model are: This invention has a simple process, which can effectively reduce the amount of by-products and heavy tar produced, thereby reducing production costs and improving the level of clean production. In this invention, methanol is introduced into a three-stage reactor in a specific ratio for a stepwise reaction, which effectively suppresses the generation of byproducts. This reduces the amount of propylene glycol isomethyl ether produced from 1.5% to 0.1% and the amount of propylene glycol dimethyl ether produced to 0.01%, thereby increasing the conversion rate of propylene glycol methyl ether from 95% to 97.5%. This invention uses a solid catalyst, namely cesium sodium X-type molecular sieve, which helps maintain the stability of the reaction pressure in the reactor and reduces the large amount of waste liquid generated by the use of liquid catalyst II. Attached Figure Description

[0014] To more clearly illustrate the technical solution of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of a propylene glycol methyl ether production system. Among them, 1-Propylene oxide feed pump, 2-Methanol feed pump, 3-First-stage steam jacket reactor, 4-Second-stage isothermal reactor, 5-Third-stage isothermal reactor, 6-Dehydroethanolating tower, 7-Distillation tower, 8-Feed pump one, 9-Feed pump two, 10-Feed pump three, 11-Feed pump four, 12-Condenser, 13-Propylene glycol methyl ether finished product tank, 14-Circulating heating pipeline, 15-Reboiler, 16-Steam inlet pipe, 17-Steam outlet pipe, 18-Dehydroethanolating gas outlet pipe, 19-Heavy tar extraction pipe, 20-Cooling water inlet pipe, 21-Cooling water outlet pipe, 22-Pneumatic regulating valve one, 23-Pneumatic regulating valve two, 24-Flow regulating valve. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] In one specific embodiment of this utility model, a production system for improving the conversion rate of propylene glycol methyl ether is as follows: Figure 1 As shown, the system includes a propylene oxide feed pump 1, a methanol feed pump 2, a primary steam jacket reactor 3, a secondary isothermal reactor 4, a tertiary isothermal reactor 5, a dealcoholization tower 6, and a distillation tower 7. The propylene oxide feed pump 1, the primary steam jacket reactor 3, the secondary isothermal reactor 4, and the tertiary isothermal reactor 5 are connected sequentially via pipelines. The methanol feed pump 2 is connected to the primary steam jacket reactor 3, the secondary isothermal reactor 4, and the tertiary isothermal reactor 5 via pipelines. The tertiary isothermal reactor 5 is connected to the middle section of the dealcoholization tower 6 via a pipeline. The bottom of the dealcoholization tower 6 is open to... The distillation column 7 is connected to the middle of the pipeline. The pipelines between the first-stage steam jacket reactor 3 and the second-stage isothermal reactor 4, the second-stage isothermal reactor 4 and the third-stage isothermal reactor 5, the third-stage isothermal reactor 5 and the dealcoholization column 6, and the dealcoholization column 6 and the distillation column 7 are respectively equipped with feed pump 1 8, feed pump 2 9, feed pump 3 10 and feed pump 4 11. The top of the distillation column 7 is connected to the condenser 12 through the pipeline. The condenser 12 is connected to the cooling water inlet pipe 20 and the cooling water outlet pipe 21. The condenser 12 is connected to the propylene glycol methyl ether finished product tank 13 through the pipeline.

[0018] A circulating heating pipe 14 is connected between the bottom and lower part of the dealcoholization column 6 and the distillation column 7. A reboiler 15 is installed on the circulating heating pipe 14. The reboiler 15 is connected to a steam inlet pipe 16 and a steam outlet pipe 17. A dealcoholization gas outlet pipe 18 is connected to the top of the dealcoholization column 6. A heavy tar outlet pipe 19 is connected to the bottom of the distillation column 7. A pneumatic regulating valve 22 is installed on the pipe between the three-stage constant temperature reactor 5 and the dealcoholization column 6. A pneumatic regulating valve 23 is installed on the pipe between the dealcoholization column 6 and the distillation column 7.

[0019] Flow regulating valves 24 are installed on the pipeline between the propylene oxide feed pump 1 and the first-stage steam jacket reactor 3, as well as on the pipelines between the methanol feed pump 2 and the first-stage steam jacket reactor 3, the second-stage isothermal reactor 4, and the third-stage isothermal reactor 5.

[0020] The primary steam jacket reactor 3, the secondary isothermal reactor 4, and the tertiary isothermal reactor 5 are all filled with X-type molecular sieves.

[0021] The process of using this utility model: The molar ratio of propylene oxide to methanol feedstock is 1:3. Propylene oxide is directly fed into the primary steam jacket reactor 3 via propylene oxide feed pump 1 through the propylene oxide feed pipe. Methanol is fed into the primary steam jacket reactor 3 (50% of the total methanol feedstock), the secondary isothermal reactor 4 (30% of the total methanol feedstock), and the tertiary isothermal reactor 5 (20% of the total methanol feedstock) via methanol feed pump 2 through the methanol feed pipe according to a set ratio. The primary steam jacket reactor 3, the secondary isothermal reactor 4, and the tertiary isothermal reactor 5 are all filled with X-type molecular sieves, specifically CsNa-X type molecular sieves produced by Shanghai Caiyou Industrial Co., Ltd. After the propylene oxide and methanol react in the primary steam jacket reactor 3, they are sequentially transported to the secondary isothermal reactor 4 and the tertiary isothermal reactor 5 via feed pump 8 and feed pump 9 for further reaction. The reaction temperature of the three reactors is controlled at 125℃ and the reaction pressure is 1.2MPa to ensure complete reaction in the reactors. After the reaction is completed, feed pump 310 sends the reactants to dealcoholization tower 6 for dealcoholization to remove excess methanol and a small amount of unreacted propylene oxide. The temperature of the bottom of the dealcoholization tower 6 is controlled at about 120°C and the temperature of the top of the tower is about 110°C. The reactants after dealcoholization are sent to distillation tower 7 by feed pump 41. The temperature of the bottom of distillation tower 7 is controlled at about 150°C and the temperature of the top of the tower is about 130°C. The propylene glycol methyl ether product is collected from the top of distillation tower 7, cooled by condenser 12, and then enters the propylene glycol methyl ether product tank 13. The by-product heavy tar is collected from the heavy tar collection pipe 19 at the bottom of distillation tower 7.

[0022] Unless otherwise specified or further limited to one preferred or alternative technical means being another, the preferred and alternative technical means disclosed in this utility model can be arbitrarily combined to form several different technical solutions. Therefore, equivalent changes made according to the claims are still within the scope of this utility model.

Claims

1. A production system for improving the conversion rate of propylene glycol methyl ether, characterized in that, The system includes a propylene oxide feed pump (1), a methanol feed pump (2), a primary steam jacket reactor (3), a secondary isothermal reactor (4), a tertiary isothermal reactor (5), a dealcoholization tower (6), and a distillation tower (7). The propylene oxide feed pump (1), the primary steam jacket reactor (3), the secondary isothermal reactor (4), and the tertiary isothermal reactor (5) are connected sequentially by pipelines. The methanol feed pump (2) is connected to the primary steam jacket reactor (3), the secondary isothermal reactor (4), and the tertiary isothermal reactor (5) by pipelines. The tertiary isothermal reactor (5) is connected to the middle of the dealcoholization tower (6) by pipelines. The bottom of the alcohol tower (6) is connected to the middle of the distillation tower (7) through a pipeline. The pipelines between the first-stage steam jacket reactor (3) and the second-stage isothermal reactor (4), the second-stage isothermal reactor (4) and the third-stage isothermal reactor (5), the third-stage isothermal reactor (5) and the alcohol removal tower (6), and the alcohol removal tower (6) and the distillation tower (7) are respectively equipped with a feed pump 1 (8), a feed pump 2 (9), a feed pump 3 (10) and a feed pump 4 (11). The top of the distillation tower (7) is connected to a condenser (12) through a pipeline. The condenser (12) is connected to a propylene glycol methyl ether finished product tank (13) through a pipeline.

2. The production system for improving the conversion rate of propylene glycol methyl ether according to claim 1, characterized in that, A circulating heating pipeline (14) is connected between the bottom and the lower part of the dealcohol column (6) and the distillation column (7). A reboiler (15) is provided on the circulating heating pipeline (14). The reboiler (15) is connected to a steam inlet pipe (16) and a steam outlet pipe (17).

3. The production system for improving the conversion rate of propylene glycol methyl ether according to claim 1, characterized in that, The top of the dealcoholization tower (6) is connected to a dealcoholization gas discharge pipe (18).

4. The production system for improving the conversion rate of propylene glycol methyl ether according to claim 1, characterized in that, The bottom of the distillation column (7) is connected to a heavy tar extraction pipe (19).

5. The production system for improving the conversion rate of propylene glycol methyl ether according to claim 1, characterized in that, The primary steam jacket reactor (3), the secondary isothermal reactor (4), and the tertiary isothermal reactor (5) are all filled with X-type molecular sieves.

6. The production system for improving the conversion rate of propylene glycol methyl ether according to claim 1, characterized in that, The condenser (12) is connected to a cooling water inlet pipe (20) and a cooling water outlet pipe (21).

7. The production system for improving the conversion rate of propylene glycol methyl ether according to claim 1, characterized in that, A pneumatic regulating valve 1 (22) is installed on the pipeline between the three-stage constant temperature reactor (5) and the deethanolating tower (6), and a pneumatic regulating valve 2 (23) is installed on the pipeline between the deethanolating tower (6) and the distillation tower (7).

8. The production system for improving the conversion rate of propylene glycol methyl ether according to claim 1, characterized in that, Flow regulating valves (24) are provided on the pipeline between the propylene oxide feed pump (1) and the first-stage steam jacket reactor (3), as well as on the pipeline between the methanol feed pump (2) and the first-stage steam jacket reactor (3), the second-stage isothermal reactor (4), and the third-stage isothermal reactor (5).

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