Plastic pall ring for filtering waste gas: 1.material:PE,PP,RPP,PVC,CPVC,PVDF 2.diameter: ... drop, low mass-transfer unit height, high flooding point, uniform gas-liquid contact, small specific gravity, high mass transfer efficiency and ... is widely used in the packing towers in petroleum industry, chemical industry, alkali-Chloride industry, coal gas industry and environmental protection, etc ...