Degassing production device and degassing production method of nitrile rubber

Abstract

The invention discloses a nitrile rubber degassing production device which comprises a first degassing tower, the top of the first degassing tower is communicated with an input assembly, the bottom of the first degassing tower is communicated with a temperature and humidity reducing device, the bottom of the first degassing tower is communicated with a first delivery pump, and the first delivery pump is communicated with a first connecting pipe and a second connecting pipe. The first connecting pipe is communicated with the top of a second degassing tower, the top of the second degassing tower is communicated with the input assembly, the bottom of the second degassing tower is communicated with the temperature and humidity reducing device, and the bottom of the second degassing tower is communicated with a second conveying pump. The first degassing tower and the second degassing tower are used for carrying out series reaction or parallel reaction to produce butadiene-acrylonitrile rubber of different grades; the problems that in the prior art, when different marks are produced, the degassing tower is prone to being blocked, and the production efficiency is low are solved.

Description

Technical Field

[0001] This invention belongs to the field of rubber production technology, and relates to a degassing production apparatus for nitrile rubber. This invention also relates to a degassing production method for nitrile rubber. Background Technology

[0002] The preparation process of nitrile rubber involves polymerizing monomers under the action of a catalyst, commonly diisopropylbenzene hydrogen peroxide, through an emulsion. The polymerization conversion rate is controlled between 68% and 89% depending on the product grade.

[0003] In addition to high-molecular-weight rubber, polymer latex also contains unreacted monomers. To separate the latex from these unreacted monomers, the latex in the production of nitrile butadiene rubber (NBR) typically employs flash evaporation followed by a degassing tower to separate the monomers from the rubber product. The undegassed latex contains unreacted monomers (butadiene and acrylonitrile), which require three stages of flash evaporation, stripping, and condensation to separate and recover them from the latex. The recovered butadiene and acrylonitrile water are recycled. The degassed latex, after acrylonitrile monomer removal, is sent to a latex blending tank to adjust the Mooney viscosity. Through processes such as coagulation, drying, weighing, briquetting, and packaging, the final product manufacturing process is completed, producing different grades of NBR products.

[0004] Degassing is the process most prone to gumming and clogging in nitrile rubber production. The nitrile latex in the input components has poor stability; in the degassing tower, as the amount of bound acrylonitrile increases and the temperature rises, the latex stability decreases. If the acrylonitrile content is high during degassing, it cannot meet the requirements for low-nitrile rubber grades. In industrial production, to avoid affecting the normal operation of other processes, degassing towers are usually operated with one standby or multiple standby towers. The degassing tower has a short operating cycle; existing degassing towers require cleaning every month, resulting in high labor intensity, frequent cleaning, and a harsh working environment. Summary of the Invention

[0005] The purpose of this invention is to provide a degassing production apparatus for nitrile rubber, which solves the problems of low degassing efficiency and short operating cycle caused by easy blockage of the channels inside the degassing tower in the production of nitrile rubber in the prior art.

[0006] Another objective of this invention is to provide a degassing production method involving nitrile rubber, which solves the problems of easy blockage in the degassing tower and low monomer removal efficiency when producing different grades in the prior art.

[0007] The technical solution adopted in this invention is a degassing production device for nitrile rubber, comprising a first degassing tower, an input component connected to the top of the first degassing tower, a de-cooling and humidifying device connected to the bottom of the first degassing tower, a first conveying pump connected to the bottom of the first degassing tower, a first connecting pipe and a second connecting pipe connected to the first connecting pipe, a second degassing tower top connected to the input component, a second degassing tower bottom connected to the de-cooling and humidifying device, and a second conveying pump connected to the bottom of the second degassing tower.

[0008] The invention is further characterized by:

[0009] The input components include a deoxygenated water tank, a defoamer tank, and an undegassed latex tank. The deoxygenated water tank, the defoamer tank, and the undegassed latex tank are all connected to the first degassing tower and the second degassing tower via pipes. A first valve is provided on the pipe connecting the undegassed latex tank to the second degassing tower.

[0010] The top of the first degassing tower is connected to a condenser, and the top of the second degassing tower is connected to the condenser, which is connected to a compressor.

[0011] The second delivery pump is connected to a latex collector, and the second connecting pipe is connected to the latex collector.

[0012] The second connecting pipe is equipped with a second valve, and the first connecting pipe is equipped with a third valve.

[0013] Another technical solution adopted in this invention is a degassing production method for nitrile rubber, using a degassing production apparatus for nitrile rubber, comprising: turning on the desuperheating humidifier and compressor to ensure that the pressure at the top of the first and second degassing towers is 8-20 kPa and the temperature at the top of the towers is 40-60°C, and the pressure at the bottom of the towers is 16-60 kPa and the temperature at the bottom of the towers is 60-80°C; adjusting the first valve, the second valve, and the third valve; opening the input component and the condenser to carry out production in the first and second degassing towers; and turning on the first and second transfer pumps to collect the produced nitrile rubber through the degassed latex tank.

[0014] Another feature of the technical solution of the present invention is that:

[0015] Nitrile rubber is either low-nitrile or high-nitrile grade nitrile rubber.

[0016] Before production of low-nitrile grade nitrile rubber, close the first and second valves and open the third valve.

[0017] Before production of high-nitrile grade nitrile rubber, close the third valve and open the second and first valves.

[0018] The beneficial effects of this invention are as follows: The degassing production apparatus for nitrile rubber of this invention includes a deoxygenated water tank connected to the tower. The addition of deoxygenated water at the top of the tower can dilute the viscosity of smaller latexes and reduce clogging of the tower plate sieve holes. The defoamer tank connected to the tower allows the defoamer to be added at the top of the tower, causing bubbles to break and be eliminated, thus improving degassing efficiency. The desuperheating and humidification device uses moist steam and degassing under high vacuum conditions, which can reduce the degassing temperature, reduce the impact of high temperature on latex stability, and extend the operating cycle. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the degassing production device for nitrile rubber of the present invention;

[0020] Figure 2 This is a schematic diagram of the input component in the degassing production device for nitrile rubber of the present invention.

[0021] In the diagram, 1. First degassing tower, 2. Input component, 3. De-icing and humidifying device, 4. First transfer pump, 5. First connecting pipe, 6. Second connecting pipe, 7. Second degassing tower, 8. Second transfer pump, 9. Deoxygenated water tank, 10. Defoamer tank, 11. Undegummed latex tank, 12. First valve, 13. Condenser, 14. Latex collector, 15. Second valve, 16. Third valve, 17. Compressor. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0023] The degassing production apparatus for nitrile rubber of the present invention, such as Figure 1 As shown, it includes a first degassing tower 1, with an input component 2 connected to the top of the first degassing tower 1, a de-cooling and humidifying device 3 connected to the bottom of the first degassing tower 1, a first delivery pump 4 connected to the bottom of the first degassing tower 1, a first connecting pipe 5 and a second connecting pipe 6 connected to the top of the second degassing tower 7, the top of the second degassing tower 7 connected to the input component 2, the bottom of the second degassing tower 7 connected to the de-cooling and humidifying device 3, and a second delivery pump 8 connected to the bottom of the second degassing tower 7.

[0024] like Figure 2 As shown, the input component 2 includes a deoxygenated water tank 9, a defoamer tank 10, and an undegassed latex tank 11. The deoxygenated water tank 9, the defoamer tank 10, and the undegassed latex tank 11 are all connected to the first degassing tower 1 and the second degassing tower 7 through pipes. A first valve 12 is provided on the pipe connecting the undegassed latex tank 11 and the second degassing tower 7.

[0025] The top of the first degassing tower 1 is connected to a condenser 13, and the top of the second degassing tower 7 is connected to the condenser 13. The condenser 13 is connected to a compressor 17.

[0026] The second delivery pump 8 is connected to the latex collector 14, and the second connecting pipe 6 is connected to the latex collector 14.

[0027] The second connecting pipe 6 is equipped with a second valve 15, and the first connecting pipe 5 is equipped with a third valve 16.

[0028] The present invention discloses a method for degassing nitrile rubber, using a nitrile rubber degassing production apparatus, comprising: turning on the desuperheating and humidifying device 3 and the compressor 17 to ensure that the top pressure of the first degassing tower 1 and the second degassing tower 7 are both 8-20 kPa and the top temperature is both 40-60°C, while the bottom pressure is both 16-60 kPa and the bottom temperature is both 60-80°C; adjusting the first valve 12, the second valve 15, and the third valve 16; turning on the input component 2 and the condenser 13 to carry out production in the first degassing tower 1 and the second degassing tower 7; and turning on the first transfer pump 4 and the second transfer pump 8 to collect the produced nitrile rubber through the degassed latex tank 11.

[0029] Nitrile rubber is either low-nitrile or high-nitrile grade nitrile rubber.

[0030] Before production of low-nitrile grade nitrile rubber, close the first valve 12 and the second valve 15, and open the third valve 16.

[0031] Before production of high-nitrile grade nitrile rubber, close the third valve 16 and open the second valve 15 and the first valve 12.

[0032] The gas phase at the top of the first degassing tower 1 and the second degassing tower 7 is collected after passing through the condenser 13. To improve the stability in latex production, deoxygenated water is added during the degassing process. Because nitrile rubber is an emulsion polymer, potassium rosinate soap is used, which causes the latex to foam in the degassing tower. Due to its high viscosity, the latex easily clogs the sieve holes of the tower plates. The deoxygenated water is added from the top of the first degassing tower 1 and the second degassing tower 7 to dilute the latex and reduce its viscosity. The temperature and pressure inside the first degassing tower 1 and the second degassing tower 7 are controlled by the desuperheating humidifier 3 and the compressor 17. The compressor inlet pressure is 8 kPa to 20 kPa, and the outlet pressure is 28 kPa to 40 kPa.

[0033] The defoamer used is silicone oil. It works by reducing surface tension, causing bubbles to burst and disappear. When added to nitrile rubber latex, the defoamer rapidly diffuses to the bubble surface, reducing the liquid's surface tension, making the bubbles unstable, and ultimately causing them to burst and release gas; thus improving degassing efficiency. The more effective the defoamer, the greater the defoaming rate and the lower the foam settling rate.

[0034] The de-heating and humidification unit 3 uses moist steam and high vacuum to degas, which can reduce the degassing temperature, reduce the impact of high temperature on latex stability, and extend the operation cycle. There are two degassing production methods: series reaction production and parallel reaction production, which can meet the acrylonitrile content requirements of different grades of products. The series reaction of the first degassing tower 1 and the second degassing tower 7 produces low-nitrile grade nitrile rubber, while the parallel reaction of the first degassing tower 1 and the second degassing tower 7 produces high-nitrile grade nitrile rubber.

[0035] Example 1

[0036] The degassing production apparatus for nitrile rubber of the present invention includes a first degassing tower 1, an input component 2 connected to the top of the first degassing tower 1, a de-cooling and humidifying device 3 connected to the bottom of the first degassing tower 1, a first delivery pump 4 connected to the bottom of the first degassing tower 1, a first connecting pipe 5 and a second connecting pipe 6 connected to the first connecting pipe 5, the top of the second degassing tower 7 connected to the input component 2, the bottom of the second degassing tower 7 connected to the de-cooling and humidifying device 3, and a second delivery pump 8 connected to the bottom of the second degassing tower 7.

[0037] Input component 2 includes a deoxygenated water tank 9, a defoamer tank 10, and an undegassed latex tank 11. The deoxygenated water tank 9, the defoamer tank 10, and the undegassed latex tank 11 are all connected to the first degassing tower 1 and the second degassing tower 7 through pipes. A first valve 12 is provided on the pipe connecting the undegassed latex tank 11 and the second degassing tower 7.

[0038] The top of the first degassing tower 1 is connected to a condenser 13, the top of the second degassing tower 7 is connected to the condenser 13, and the condenser 13 is connected to a compressor 17; the second delivery pump 8 is connected to a latex collector 14, and the second connecting pipe 6 is connected to the latex collector 14; the second connecting pipe 6 is equipped with a second valve 15, and the first connecting pipe 5 is equipped with a third valve 16.

[0039] A degassing production method for nitrile rubber, using a nitrile rubber degassing production apparatus, includes: turning on the desuperheating and humidifying unit 3 and the compressor 17 until the top pressure of the first degassing tower 1 and the second degassing tower 7 are both 8 kPa and the top temperature of both are 40°C, the pressure of both tower bottoms is 16 kPa and the bottom temperature of both are 60°C; closing the first valve 12 and the second valve 15, and opening the third valve 16; opening the input component 2 and the condenser 13, and carrying out production in the first degassing tower 1 and the second degassing tower 7; turning on the first transfer pump 4 and the second transfer pump 8, and collecting the produced low-nitrile grade nitrile rubber through the degassing latex tank 11.

[0040] This invention has been successfully applied in the 35,000-ton / year special nitrile rubber unit of Lanzhou Petrochemical. From the unit's start-up in March 2022 to July 2023, the degassing tower operated stably without requiring cleaning or rubber buildup on the trays. The acrylonitrile content in the degassed rubber solution was 76 ppm, and the unit's steam consumption was reduced by approximately 120 tons per year compared to similar units. While ensuring stable operation, energy conservation and clean production were achieved.

[0041] Example 2

[0042] The degassing production apparatus for nitrile rubber of the present invention includes a first degassing tower 1, an input component 2 connected to the top of the first degassing tower 1, a de-cooling and humidifying device 3 connected to the bottom of the first degassing tower 1, a first delivery pump 4 connected to the bottom of the first degassing tower 1, a first connecting pipe 5 and a second connecting pipe 6 connected to the first connecting pipe 5, the top of the second degassing tower 7 connected to the input component 2, the bottom of the second degassing tower 7 connected to the de-cooling and humidifying device 3, and a second delivery pump 8 connected to the bottom of the second degassing tower 7.

[0043] Input component 2 includes a deoxygenated water tank 9, a defoamer tank 10, and an undegassed latex tank 11. The deoxygenated water tank 9, the defoamer tank 10, and the undegassed latex tank 11 are all connected to the first degassing tower 1 and the second degassing tower 7 through pipes. A first valve 12 is provided on the pipe connecting the undegassed latex tank 11 and the second degassing tower 7.

[0044] The top of the first degassing tower 1 is connected to a condenser 13, the top of the second degassing tower 7 is connected to the condenser 13, and the condenser 13 is connected to a compressor 17; the second delivery pump 8 is connected to a latex collector 14, and the second connecting pipe 6 is connected to the latex collector 14; the second connecting pipe 6 is equipped with a second valve 15, and the first connecting pipe 5 is equipped with a third valve 16.

[0045] A degassing production method for nitrile rubber, using a nitrile rubber degassing production apparatus, includes: turning on the desuperheating and humidifying unit 3 and the compressor 17 until the top pressure of the first degassing tower 1 and the second degassing tower 7 are both 10 kPa and the top temperature is both 50°C, the bottom pressure is both 40 kPa and the bottom temperature is both 70°C; closing the third valve 16, opening the second valve 15 and opening the first valve 12; turning on the input component 2 and the condenser 13, and carrying out production in the first degassing tower 1 and the second degassing tower 7; turning on the first transfer pump 4 and the second transfer pump 8, and collecting the produced high-nitrile grade nitrile rubber through the degassing latex tank 11.

[0046] Example 3

[0047] The degassing production apparatus for nitrile rubber of the present invention includes a first degassing tower 1, an input component 2 connected to the top of the first degassing tower 1, a de-cooling and humidifying device 3 connected to the bottom of the first degassing tower 1, a first delivery pump 4 connected to the bottom of the first degassing tower 1, a first connecting pipe 5 and a second connecting pipe 6 connected to the first connecting pipe 5, the top of the second degassing tower 7 connected to the input component 2, the bottom of the second degassing tower 7 connected to the de-cooling and humidifying device 3, and a second delivery pump 8 connected to the bottom of the second degassing tower 7.

[0048] Input component 2 includes a deoxygenated water tank 9, a defoamer tank 10, and an undegassed latex tank 11. The deoxygenated water tank 9, the defoamer tank 10, and the undegassed latex tank 11 are all connected to the first degassing tower 1 and the second degassing tower 7 through pipes. A first valve 12 is provided on the pipe connecting the undegassed latex tank 11 and the second degassing tower 7.

[0049] The top of the first degassing tower 1 is connected to a condenser 13, the top of the second degassing tower 7 is connected to the condenser 13, and the condenser 13 is connected to a compressor 17; the second delivery pump 8 is connected to a latex collector 14, and the second connecting pipe 6 is connected to the latex collector 14; the second connecting pipe 6 is equipped with a second valve 15, and the first connecting pipe 5 is equipped with a third valve 16.

[0050] A degassing production method for nitrile rubber, using a nitrile rubber degassing production apparatus, includes: turning on the desuperheating and humidifying unit 3 and the compressor 17 until the pressure at the top of the first degassing tower 1 and the second degassing tower 7 are both 20 kPa and the temperature at the top of the towers are both 60°C, the pressure at the bottom of the towers is both 60 kPa and the temperature at the bottom of the towers is both 80°C; adjusting the first valve 12, the second valve 15 and the third valve 16; turning on the input component 2 and the condenser 13 to carry out production in the first degassing tower 1 and the second degassing tower 7; and turning on the first transfer pump 4 and the second transfer pump 8 to collect the produced nitrile rubber through the degassed latex tank 11.

Claims

1. A degassing production apparatus for nitrile rubber, characterized in that, The first degassing tower (1) is connected to an input component (2) at its top, a de-heating and humidifying device (3) at its bottom, a first delivery pump (4) at its bottom, a first connecting pipe (5) and a second connecting pipe (6) at its top, a second degassing tower (7) at its top, the input component (2) at its bottom, the de-heating and humidifying device (3) at its bottom, and a second delivery pump (8) at its bottom.

2. The degassing production apparatus for nitrile rubber according to claim 1, characterized in that, The input component (2) includes a deoxygenated water tank (9), a defoamer tank (10), and an undegassed latex tank (11). The deoxygenated water tank (9), the defoamer tank (10), and the undegassed latex tank (11) are all connected to the first degassing tower (1) and the second degassing tower (7) through pipes. A first valve (12) is provided on the pipe connecting the undegassed latex tank (11) and the second degassing tower (7).

3. The degassing production apparatus for nitrile rubber according to claim 1, characterized in that, The top of the first degassing tower (1) is connected to a condenser (13), and the top of the second degassing tower (7) is connected to the condenser (13), and the condenser (13) is connected to a compressor (17).

4. The degassing production apparatus for nitrile rubber according to claim 1, characterized in that, The second delivery pump (8) is connected to a latex collector (14), and the second connecting pipe (6) is connected to the latex collector (14).

5. The degassing production apparatus for nitrile rubber according to claim 1, characterized in that, The second connecting pipe (6) is provided with a second valve (15), and the first connecting pipe (5) is provided with a third valve (16).

6. A method for producing nitrile rubber by degassing, using the nitrile rubber degassing production apparatus according to claim 5, characterized in that, include: Turn on the de-cooling humidifier (3) and compressor (17) to ensure that the pressure at the top of the first degassing tower (1) and the temperature at the top of the second degassing tower (7) are both 8-20 kPa and 40-60°C, respectively, and that the pressure at the bottom of the tower is both 16-60 kPa and the temperature at the bottom of the tower is both 60-80°C. Adjust the first valve (12), the second valve (15) and the third valve (16). Turn on the input component (2) and the condenser (13) to carry out production in the first degassing tower (1) and the second degassing tower (7). Turn on the first transfer pump (4) and the second transfer pump (8) to collect the produced nitrile rubber through the degassing latex tank (11).

7. The method for degassing nitrile rubber according to claim 6, characterized in that, The nitrile rubber is either a low-nitrile grade or a high-nitrile grade.

8. The method for producing nitrile rubber by degassing according to claim 7, characterized in that, Before production of the low-nitrile grade nitrile rubber, the first valve (12) and the second valve (15) are closed, and the third valve (16) is opened.

9. The method for producing nitrile rubber by degassing according to claim 7, characterized in that, Before production of the high-nitrile grade nitrile rubber, the third valve (16) is closed, the second valve (15) is opened, and the first valve (12) is opened.

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