In the production process of diketene, the use of vacuum pump is obviously superior to other vacuum pumps. The use of vacuum pump has better economic benefits and technical value, and should be promoted. If it can be popularized and applied in the diketene industry nationwide, it will be better for the cracking tail gas pump.
Diketene, also known as acetyl vinyl ketone and diphenyl ketone, is a colorless or yellowish liquid with strong pungent smell. Because there are two double bonds in the structure of diketene, it is highly unsaturated and has high chemical activity and excellent reaction performance in organic synthesis. It can react with alcohol, amine, halogen, aldehyde, acid, etc. it is an important intermediate in organic synthesis and widely used in medicine, pesticide, dye, food and other industries.
Working principle of rotary vane vacuum pump: the rotary vane pump is mainly composed of stator, rotor, rotary vane, fixed cover, spring and other parts. Its structure is to use the rotor installed eccentrically in the stator cavity (the gap between the outer circle of the rotor and the inner surface of the stator is very small) and the two pieces of rotating pieces which slide in the rotor groove and cling to the inner wall of the stator with the help of spring tension and centrifugal force. When the rotor rotates, it always slides along the inner wall of the stator.
When the rotor rotates in the direction shown in the figure, the volume of space a connected with the suction port increases continuously, and the pressure in space a decreases continuously. When the pressure in space a is lower than the pressure in the pumped container, according to the principle of gas pressure balance, the pumped gas is continuously Suction chamber a is in the process of suction. The volume of cavity B is decreasing and the pressure is increasing, which is in the process of compression. The volume of space C connected with the exhaust port is further reduced, and the pressure of space C is further increased. When the pressure of the gas is greater than the exhaust pressure, the compressed gas pushes the exhaust valve, and the extracted gas continuously passes through the oil layer in the oil tank and discharges to the atmosphere. During the continuous operation of the pump, the process of suction, compression and exhaust is continuously carried out, so as to achieve continuous operation Purpose of air extraction.
The exhaust valve is immersed in the oil to prevent the air from flowing into the pump. The oil enters the pump cavity through the clearance, oil hole and exhaust valve on the pump body, so that all moving surfaces in the pump cavity are covered by oil, forming a seal between the suction cavity and the exhaust cavity. At the same time, the oil is full of all harmful spaces, so as to eliminate their impact on the ultimate vacuum.
Application effect of rotary vane vacuum pump in the production process of diketene
1. The yield of diethylene ketone was improved obviously. Due to the use of imported rotary vane vacuum pump, the vacuum degree of the system is increased, the boiling point of the diketene is reduced, the refining temperature is reduced, the polymerization and carbon loss of the diketene are reduced; the evaporation speed of the diketene is accelerated, the residence time of the diketene in the high temperature area is reduced, and the carbon loss of the polymerization of the diketene is also reduced And the yield of diketene was increased.
2. The service cycle of the pump is extended, and the number of pump washing is significantly reduced. In the refining process of diketene, the low boiling matter in the crude diketene is evaporated and pumped into the atmosphere through the rotary vane vacuum pump; the purpose of washing the pump is to reduce the friction heat, thus reducing the phenomenon of polymerization and carbon deposition, prolonging the service cycle of the rotary vane vacuum pump and reducing the number of washing the pump.
3. The amount of residue is reduced and easy to discharge. Due to the high vacuum limit of the rotary vane vacuum pump, the boiling point of the diketene is reduced, and the operating temperature is reduced, which not only reduces the polymerization loss, but also reduces the polymerization depth of the polymer, so that the amount of residue is small, the quality is thin, and the emission is always easy.
4. Low consumption of lubricating oil.
5. Easy operation and stable operation. Because the structure of the rotary vane vacuum pump is simple and reasonable, the operation is easy and the operation is stable.