Device for preparing dimethyl disulfide by sodium methyl mercaptide oxidation method

Abstract

The utility model discloses a device for preparing dimethyl disulfide by a sodium methyl mercaptide oxidation method, which comprises an alkali absorption methyl mercaptide tubular reactor, a sodium methyl mercaptide oxidation tubular reactor, a degassing tower, a flash tank, a liquid separation tank, a double-tower rectification system, a reagent alkali storage tank, a wastewater storage tank and a vacuum pipeline, an outlet of the alkali absorption methyl mercaptan tubular reactor is connected with an inlet of the sodium methyl mercaptide oxidation tubular reactor, an outlet of the sodium methyl mercaptide oxidation tubular reactor is connected with the degassing tower, the degassing tower is connected with the flash tank, and the top of the flash tank is connected with the condenser; the condenser is connected with a vacuum pipeline, and the bottom of the condenser is connected with a liquid separation tank; and the liquid separation tank is connected with the double-tower rectification device. According to the utility model, side reactions can be effectively inhibited, the conversion per pass of sodium methyl mercaptide is improved, and the energy consumption of the system is reduced.

Description

Technical Field

[0001] The utility model relates to a device for preparing dimethyl disulfide by oxidizing methyl mercaptan salt, in particular to an optimized device for preparing dimethyl disulfide by a sodium methyl mercaptan oxidation method. Background Art

[0002] Dimethyl disulfide is both an important chemical end product and an important organic intermediate. It is a fine chemical product and is widely used in pesticides, petroleum, chemicals, rubber and other industries.

[0003] The main methods for producing dimethyl disulfide on the market currently include the dimethyl sulfate method, the methyl mercaptan sulfidation method, and the methyl mercaptan salt oxidation method. The dimethyl sulfate method uses the highly toxic and corrosive raw material dimethyl sulfate, posing high safety and environmental risks. The methyl mercaptan sulfidation method, on the other hand, suffers from significant side reactions in actual production. The sulfidation reaction generates dimethyl polysulfide, making subsequent product purification difficult, and also resulting in high production costs and energy consumption.

[0004] The methyl mercaptan salt oxidation method can co-produce methyl mercaptan salt at the front end, and the methyl mercaptan salt can be oxidized by oxygen in one step at the back end to obtain dimethyl disulfide product. The raw materials are low-toxic or non-toxic. At the same time, the reaction of the aqueous solution system is more controllable and has a high safety factor. Summary of the Invention

[0005] The utility model provides a device for efficiently oxidizing a sodium methyl mercaptan solution to generate dimethyl disulfide, which adopts a short process, low energy consumption, and precise temperature control to reduce side reactions, thereby obtaining a high-quality dimethyl disulfide product.

[0006] To achieve the above effects, this trial model is implemented through the following scheme:

[0007] A device for preparing dimethyl disulfide by sodium methyl mercaptan oxidation method, comprising an alkali absorption methyl mercaptan tubular reactor, a sodium methyl mercaptan oxidation tubular reactor, a degassing tower, a flash tank, a condenser, a separator, a double-tower distillation device, an alkali storage tank, a wastewater storage tank, and a vacuum pipeline.

[0008] The outlet of the alkali absorption methyl mercaptan tubular reactor is connected to the inlet of the sodium methyl mercaptan oxidation tubular reactor, the outlet of the sodium methyl mercaptan oxidation tubular reactor is connected to a degassing tower, the degassing tower is connected to a flash tank, and the top of the flash tank is connected to a condenser;

[0009] The condenser is connected to a vacuum pipeline, and the bottom of the condenser is connected to a separator tank; the separator tank is connected to a double-tower distillation device.

[0010] The alkali absorption methyl mercaptan tubular reactor is connected to a circulating alkali solution feeding pipe and a methyl mercaptan feeding pipe, wherein the methyl mercaptan feeding pipe is connected to a distributor and enters the alkali absorption methyl mercaptan tubular reactor.

[0011] The sodium methyl mercaptan oxidation tubular reactor is provided with an oxygen feed pipe; the oxygen feed pipe is connected to a distributor and enters the sodium methyl mercaptan oxidation tubular reactor, and a certain number of bubbles are respectively installed on the main pipe and branch pipe of the calandria distributor.

[0012] The bottom of the flash tank is connected to the alkali storage tank;

[0013] The separator tank is also connected to the wastewater storage tank.

[0014] The alkali absorption methyl mercaptan tubular reactor and the sodium methyl mercaptan oxidation tubular reactor are provided with multi-stage outer jacket temperature control.

[0015] The degassing tower is equipped with an online oxygen content detection instrument, which is linked with the nitrogen purge flow to control the oxygen content.

[0016] The utility model prepares dimethyl disulfide using a tubular reactor and is provided with a multi-stage outer jacket temperature control to meet the heating and cooling requirements of different reaction sections. The sodium methyl mercaptan oxidation reaction can utilize the front-end alkali to absorb the waste heat of methyl mercaptan, and precise temperature control can effectively reduce side reactions. Methyl mercaptan and oxygen are fed through a distributor, and a certain number of evenly distributed bubbles are installed on the main and branch pipes of the calandria distributor, allowing gas to enter in the form of microbubbles, increasing the gas-liquid reaction contact area and improving reaction efficiency. The degassing tower accurately analyzes the oxygen content in the gas phase through an oxygen content analyzer, and a nitrogen flow rate is introduced in a chain to avoid reaching the explosion limit of the explosive mixed gas and ensure safety. The post-reaction feed liquid is flash evaporated, and dimethyl disulfide and part of the water are extracted together using the reaction waste heat. While completing the extraction of dimethyl disulfide, the alkali solution containing the catalyst is concentrated, reducing energy consumption and improving the quality of the crude dimethyl disulfide. Combined with double-tower distillation, the quality of the dimethyl disulfide finished product will be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further described below through the accompanying drawings and specific implementation cases.

[0018] Figure 1 Schematic diagram of the optimized setup for preparing dimethyl disulfide using the sodium methyl mercaptan oxidation process. The diagram includes: 1. circulating alkali feed pipe, 2. methyl mercaptan feed pipe, 3. tubular reactor for alkali absorption of methyl mercaptan, 4. oxygen feed pipe, 5. tubular reactor for sodium methyl mercaptan oxidation, 6. degassing tower, 7. flash tank, 8. condenser, 9. vacuum line, 10. separator tank, 11. caustic soda storage tank, 12. wastewater storage tank, and 13. double-tower distillation unit. DETAILED DESCRIPTION

[0019] Example 1

[0020] An optimized device for preparing dimethyl disulfide by a sodium methyl mercaptan oxidation method, wherein the outlet of an alkali absorption methyl mercaptan tubular reactor 3 is connected to the inlet of a sodium methyl mercaptan oxidation tubular reactor 5, the outlet of the sodium methyl mercaptan oxidation tubular reactor 5 is connected to a degassing tower 6, the degassing tower 6 is connected to a flash tank 7, and the top of the flash tank 7 is connected to a condenser 8;

[0021] The condenser 8 is connected to a vacuum pipeline 9 , and the bottom of the condenser 8 is connected to a separator 10 ; the separator 10 is connected to a double-tower distillation device 13 .

[0022] The alkali absorption methyl mercaptan tubular reactor 3 is connected to a circulating alkali solution feed pipe 1 and a methyl mercaptan feed pipe 2, wherein the methyl mercaptan feed pipe 2 is connected to a distributor and enters the alkali absorption methyl mercaptan tubular reactor 3.

[0023] The sodium methyl mercaptan oxidation tubular reactor 5 is provided with an oxygen feed pipe 4; the oxygen feed pipe 4 is connected to the distributor and enters the sodium methyl mercaptan oxidation tubular reactor 5, and a certain number of bubbles are respectively installed on the main pipe and branch pipe of the calandria distributor.

[0024] The bottom of the flash tank 7 is connected to the alkali storage tank 11;

[0025] The liquid separation tank 10 is also connected to the wastewater storage tank 12 .

[0026] The alkali absorption methyl mercaptan tubular reactor 3 and the sodium methyl mercaptan oxidation tubular reactor 5 are provided with multi-stage outer jacket temperature control.

[0027] The degassing tower 6 is equipped with an online oxygen content detection instrument, which is linked with the nitrogen purge flow to control the oxygen content.

[0028] Example 2

[0029] Using the apparatus of Example 1, the circulating alkali solution of the dissolved catalyst and methyl mercaptan enter the alkali absorption methyl mercaptan tubular reactor 3 to generate sodium methyl mercaptide. The feed liquid then enters the sodium methyl mercaptide oxidation tubular reactor 5 to generate dimethyl disulfide. After degassing, flash distillation, and separation, crude disulfide is obtained, and then the finished product dimethyl disulfide is obtained by distillation. The sodium methyl mercaptide single-pass oxidation efficiency is 85%, the main gas phase content is 99.95%, and the moisture is 50ppm.

Claims

1. A device for preparing dimethyl disulfide by sodium methyl mercaptan oxidation method, characterized in that: The invention comprises an alkali absorption methyl mercaptan tubular reactor (3), a sodium methyl mercaptan oxidation tubular reactor (5), a degassing tower (6), a flash tank (7), a condenser (8), a liquid separator (10), a double-tower distillation device (13), an alkali storage tank (11), a wastewater storage tank (12), and a vacuum pipeline (9), and is characterized by: The outlet of the alkali absorption methyl mercaptan tubular reactor (3) is connected to the inlet of the sodium methyl mercaptan oxidation tubular reactor (5), the outlet of the sodium methyl mercaptan oxidation tubular reactor (5) is connected to the degassing tower (6), the degassing tower (6) is connected to the flash tank (7), and the top of the flash tank (7) is connected to the condenser (8); The condenser (8) is connected to a vacuum pipeline (9), and the bottom of the condenser (8) is connected to a liquid separator (10); the liquid separator (10) is connected to a double-tower distillation device (13).

2. The sodium methyl mercaptan oxidation method for preparing dimethyl disulfide according to claim 1, wherein The alkali absorption methyl mercaptan tubular reactor (3) is connected to a circulating alkali solution feed pipe (1) and a methyl mercaptan feed pipe (2), wherein the methyl mercaptan feed pipe (2) is connected to a distributor and enters the alkali absorption methyl mercaptan tubular reactor (3).

3. The sodium methyl mercaptan oxidation method for preparing dimethyl disulfide according to claim 1, wherein The sodium methyl mercaptan oxidation tubular reactor (5) is provided with an oxygen feed pipe (4); the oxygen feed pipe (4) is connected to a distributor and enters the sodium methyl mercaptan oxidation tubular reactor (5), and a certain number of bubbles are respectively installed on the main pipe and branch pipe of the calandria distributor.

4. The sodium methyl mercaptan oxidation method for preparing dimethyl disulfide according to claim 1, characterized in that: The bottom of the flash tank (7) is connected to the alkali storage tank (11); The liquid separation tank (10) is also connected to the wastewater storage tank (12).

5. The device for preparing dimethyl disulfide by sodium methyl mercaptan oxidation method according to claim 1, characterized in that, The alkali absorption methyl mercaptan tubular reactor (3) and the sodium methyl mercaptan oxidation tubular reactor (5) are provided with multi-stage outer jacket temperature control.

6. The device for preparing dimethyl disulfide by sodium methyl mercaptan oxidation method according to claim 1, characterized in that, The degassing tower (6) is provided with an online oxygen content detection instrument, which is linked with the nitrogen purge flow rate to control the oxygen content.

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