Liquid ring vacuum pumps in PVC process
PVC resins are basis of PVC plastics. Because of its heat instability, it has bad processability and can not be used alone, so it must be combined with several additives to bring about its value. Common additives are stabilizer, plasticizer and fillings. According to amount of plasticizer, PVC plastic present different feature in appearance, such as hard, soft, or pasty, this makes it widely used in many fields and multi-produced.
In PVC production, its main process include ionic membrane caustic soda and PVC polymerization.
Applications
Application of liquid ring vacuum pumps in PVC process of ionic membrane caustic soda and PVC polymerization:
• VCM recycling
• Convey Hydrogen
• Dilute brine dechlorination
• Convey Acetylene
• VCM recycle
In process of producing PVC, the VCM residue of reaction process is firstly pumped and transported into storage tank by liquid ring pump, and then pressurized to about 0.55 to 0.65 MPA through compressor; at last stored as liquid in recycling tank for further reaction.
SY / 2 SY series water ring compressors possess high exhaust pressure, compact structure, smooth operation, and isothermal compression, etc. They are especially suitable to pump gases which contain vapor, dust, inflammable, explosive, and reactive in high temperature. Flexible exhaust valve structure in high pressure side guarantees the exhaust pressure within design scope. External flushing double mechanical seal ensures no leakage of the compressed medium.
• Convey Hydrogen
In the process of transporting, hydrogen is surrounded by thick water ring, and the heat produced is taken away promptly. Besides, compressor is low speed, therefore it is low in vibration and temperature rise (generally below 10 ℃), safe and reliable.
Dilute brine flowed from ionic membrane electrolyzer contains certain amount of free chlorine,and it must be dechlorinated before entering brine refining system. Dilute brine flows into dechlorination column and boils as boiling point is lowered in vacuum state,then chlorine gas escapes from dilute brine and is extracted by water ring vacuum pump.
Whole titanium vacuum pump unit by Jinggong can realize anti-corrosion. Corrosion-resistant pump refers to the pump whose liquid-contact components are made of titanium or titanium alloy and seal is double mechanical seal. It is suitable to transport a variety of organic and inorganic corrosive liquid, and especially chlorine saline solution, which is incomparable of common material pump.
• Convey Acetylene
Acetylene produced in the calcium carbide acetylene method need to be transported for recovery. Considering its properties of flammable, explosive, unfavorable in high temperature (over 80 ℃) and high pressure (higher than 0.15 MPa), water ring pumps are recommended, with the advantages as follows:
1. When pumps are used as compressor, the wide clearance between impeller and casing avoids sparking caused by friction; water used as operating liquid make acetylene wet to prevent explosion.
2. Liquid ring pumps’ feature of suction, low pressure, but high capacity is suitable to transport acetylene.
3. Gas is isothermally compressed in the pump, about 30 ℃ ~50 ℃ , this avoids explosion in high temperature.