Octamethylcyclotetrasiloxane production device

Abstract

The utility model discloses an octamethylcyclotetrasiloxane production device, which belongs to the field of distillation and comprises a distillation tower, a heating device positioned below the distillation tower, a condensation pipe positioned at the output end of the distillation tower and a storage bottle for receiving condensed liquid. Compared with the prior art, the condensation device has the advantages that the condensation pipes for receiving different evaporation temperatures are uniformly connected through the shunting pipelines, and the opening and closing of the condensation pipes are controlled through the electromagnetic on-off valves; the gas concentration monitor for detecting the dimethyldichlorosilane is mounted at the top end of the shunting pipeline, and when the concentration is reduced to a certain range, the distillation tower is preheated and heated to enable the temperature of the distillation tower to be close to 173 DEG C, so that the effect that the distillation tower can be recovered without influencing the volatilization of the dimethyldichlorosilane is achieved. The octamethylcyclotetrasiloxane in the next stage can be ensured to quickly enter the distillation stage.

Description

Technical Field

[0001] This utility model relates to the field of distillation, specifically to an octamethylcyclotetrasiloxane production apparatus. Background Technology

[0002] Octamethylcyclotetrasiloxane is a compound obtained through separation and distillation of a product synthesized from dimethyldichlorosilane via hydrolysis. It is an important intermediate in the organosilicon industry and is widely used as a lubricant and rust inhibitor in various instruments. The existing method for producing octamethylcyclotetrasiloxane involves adding dimethyldichlorosilane dropwise to water, maintaining the temperature at 30-40°C, allowing the layers to separate, discarding the acidic water, and hydrolyzing the oily substance with sodium hydroxide solution. The hydrolysate and 0.5%-2% potassium hydroxide are then added to a pyrolysis reactor and pyrolyzed at 120-140°C and a vacuum of 99.8 kPa. The pyrolysis product is fractionated, and the fraction collected at 173-176°C yields octamethylcyclotetrasiloxane. Byproducts generated during fractionation include oligomers and unreacted raw materials, such as dimethyldichlorosilane, whose vaporization temperature is 70°C.

[0003] The commonly used fractionation method at present is to heat the cracked product in a distillation column, and use the vaporization temperature difference to separate different substances in the distillation column. Then, the gas is cooled by a condenser and condensed into a liquid. The liquid product then flows into the corresponding storage bottle for preservation.

[0004] However, during the gas evaporation process, whether the distillation step is completed depends entirely on experience, or on observing whether the condenser stops dripping in the previous temperature difference. Although this method can solve the accuracy of fractionation, it is difficult to detect the amount of gas evaporated in the distillation column in time, which makes it difficult to quickly preheat and increase the temperature in the next stage. Utility Model Content

[0005] The technical problem this invention aims to solve is that in existing octamethylcyclotetrasiloxane production equipment, it is difficult to determine the concentration of the finished product at this stage during fractionation, thus making it difficult to preheat the condensation of the next stage.

[0006] To solve the above-mentioned technical problems, the technical solution provided by this utility model is as follows: an octamethylcyclotetrasiloxane production device, including a distillation column, a heating device located below the distillation column, a condenser located at the output end of the distillation column, and a storage bottle for receiving condensed liquid. A diversion pipe is provided at the output port of the top of the distillation column. The output port of the diversion pipe is respectively connected to a gas condenser and a straight condenser of the condenser. A gas concentration monitor for monitoring the content of by-products is provided at the top output port of the diversion pipe, and electromagnetic check valves are provided at the inlets of the gas condenser and the straight condenser.

[0007] As an improvement, a temperature sensor for monitoring the temperature of the distillation column is provided at the top of the distillation column.

[0008] As an improvement, the heating device is a temperature-adjustable electromagnetic heater, and a temperature monitoring device for receiving monitoring data from a temperature sensor is provided on one side of the electromagnetic heater.

[0009] As an improvement, the gas condenser and the straight condenser are cooled by a blower and a vertical condensate pump, respectively.

[0010] As an improvement, both the gas condenser and the straight condenser are supported by inclined supports.

[0011] As an improvement, a leak-proof solenoid valve is provided between the inlet of the diversion pipe and the outlet of the distillation column to prevent gas leakage.

[0012] The advantages of this invention compared to existing technologies are as follows: This device connects condenser tubes receiving different evaporation temperatures through a distribution pipe and controls their opening and closing through an electromagnetic stop valve. In order to detect the gas volatilization concentration at this stage in a timely manner, a gas concentration monitor for dimethyldichlorosilane is installed at the top of the distribution pipe. When the concentration drops to a certain range, the distillation column is preheated to a temperature close to 173 degrees Celsius. This ensures that octamethylcyclotetrasiloxane can quickly enter the distillation stage without affecting the volatilization of dimethyldichlorosilane. Attached Figure Description

[0013] Figure 1 This is a front view of the overall structure of an octamethylcyclotetrasiloxane production apparatus according to this utility model.

[0014] Figure 2 This is a rear view of the overall structure of an octamethylcyclotetrasiloxane production apparatus according to this utility model.

[0015] Figure 3 This is a cross-sectional view of the gas condenser tube of an octamethylcyclotetrasiloxane production apparatus according to this utility model.

[0016] Figure 4 This is a cross-sectional view of a straight condenser tube in an octamethylcyclotetrasiloxane production apparatus according to this utility model.

[0017] As shown in the figure: 1. Distillation column; 2. Heating device; 21. Temperature control monitor; 3. Condenser; 31. Gas condenser; 311. Blower; 32. Straight condenser; 321. Vertical condensate pump; 4. Storage bottle; 5. Diversion pipe; 6. Gas concentration monitor; 7. Electromagnetic stop valve; 8. Temperature sensor; 9. Leak-proof solenoid valve. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings.

[0019] As per the instruction manual Figure 1 , 2 As shown in Figures 3 and 4, a common distiller at present includes a distillation column 1, a heating device 2 located below the distillation column 1, a condenser 3 located at the output end of the distillation column 1, and a storage bottle 4 for receiving condensate. The heating device 2 is a temperature-adjustable electromagnetic heater so that the temperature can be quickly controlled. In order to facilitate the detection of the temperature in the distillation column 1, a temperature sensor 8 is provided at the top of the distillation column 1 to monitor the temperature of the distillation column 1, and a temperature monitoring device 21 is provided on one side of the electromagnetic heater to receive the monitoring data of the temperature sensor 8, so as to facilitate the adjustment of the temperature of the distillation column 1.

[0020] To facilitate the separation of products from different stages, a distillation column 1 is provided with a diversion pipe 5 at the top outlet. The diversion pipe 5 has a cross-shaped structure. The outlet of the diversion pipe 5 is connected to the gas condenser 31 and the straight condenser 32 of the condenser 3, respectively. Octamethylcyclotetrasiloxane is separated by the gas condenser 31, while dimethyldichlorosilane is separated by the straight condenser 32. The gas condenser 31 and the straight condenser 32 are cooled by a blower 311 and a vertical condensate pump 321, respectively.

[0021] A gas concentration monitor 6 is installed at the top outlet of the diversion pipe 5 to monitor the content of by-products. This monitor detects the content of dimethyldichlorosilane and octamethylcyclotetrasiloxane in the gas during distillation of dimethyldichlorosilane. The gas concentration monitor 6 passes through the top outlet of the diversion pipe 5. To facilitate monitoring of the fixed condenser 3, both the gas condenser 31 and the straight condenser 32 are supported by inclined brackets. To prevent cross-contamination during condensation, both the gas condenser 31 and the straight condenser 32 are equipped with electromagnetic check valves 7. When the condenser 3 or the diversion pipe 5 in the equipment malfunctions, a leak-proof electromagnetic valve 9 is installed between the inlet of the diversion pipe 5 and the outlet of the distillation tower 1 to prevent gas leakage and stop the damage in time.

[0022] In specific implementation of this invention, the pyrolysis products are placed in distillation column 1, heating device 2 is started, and temperature sensor 8 monitors the temperature change inside distillation column 1, keeping it between 70 and 100°C. Electromagnetic stop valve 7 on one side of straight condenser 32 is opened, allowing dimethyldichlorosilane gas to pass through straight condenser 32 for cooling, and then flow into storage bottle 4 behind straight condenser 32 for preservation. When gas concentration monitor 6 detects that the concentration of dimethyldichlorosilane gas is below a certain value, it sends a corresponding warning signal to temperature control monitor 21. Upon receiving the signal, temperature control monitor 21 triggers heating device 2 to perform the next stage of preheating. When the gas concentration monitor 6 indicates that the byproduct discharge is complete, heating device 2 raises the temperature to 173-176°C, electromagnetic stop valve 7 on one side of straight condenser 32 is closed, while electromagnetic stop valve 7 in front of gas condenser 31 on the other side is opened for condensation of octamethylcyclotetrasiloxane.

[0023] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. An apparatus for producing octamethylcyclotetrasiloxane, comprising a distillation column (1), a heating device (2) located below the distillation column (1), a condenser (3) located at the output end of the distillation column (1), and a storage bottle (4) for receiving condensate, characterized in that: A diversion pipe (5) is provided at the top outlet of the distillation tower (1). The gas condenser (31) and the straight condenser (32) of the condenser (3) are connected to the outlet of the diversion pipe (5). A gas concentration monitor (6) for monitoring the content of by-products is provided at the top outlet of the diversion pipe (5). Electromagnetic check valves (7) are provided at the inlets of the gas condenser (31) and the straight condenser (32).

2. The octamethylcyclotetrasiloxane production apparatus according to claim 1, characterized in that: A temperature sensor (8) for monitoring the temperature of the distillation column (1) is provided at the top of the distillation column (1).

3. The octamethylcyclotetrasiloxane production apparatus according to claim 2, characterized in that: The heating device (2) is a temperature-adjustable electromagnetic heater, and a temperature monitoring device (21) is provided on one side of the electromagnetic heater to receive monitoring data from the temperature sensor (8).

4. The octamethylcyclotetrasiloxane production apparatus according to claim 1, characterized in that: The gas condenser (31) and the straight condenser (32) are cooled by a blower (311) and a vertical condensate pump (321), respectively.

5. An octamethylcyclotetrasiloxane production apparatus according to claim 1, characterized in that: Both the gas condenser (31) and the straight condenser (32) are supported by inclined supports.

6. The octamethylcyclotetrasiloxane production apparatus according to claim 1, characterized in that: A leak-proof solenoid valve (9) is provided between the inlet of the diversion pipe (5) and the outlet of the distillation column (1) to prevent gas leakage.

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