VOCs Recovery Membrane


‌Working Principle

The organic vapor separation membrane is a rubbery polymer membrane. The separation process is based on selective dissolution, exploiting differences in solubility and permeability rates of various organic vapors within the membrane. Gases with larger molecular weights and higher boiling points (e.g., ethylene, propylene, chloromethane, vinyl chloride, butadiene, and other light hydrocarbons) have higher solubility and faster permeability rates within the membrane. This enables their separation from smaller molecular weight, lower boiling point gases (e.g., H2, N2, CH4).

Driven by the pressure differential across the membrane, the incoming stream is divided into two parts: the permeate and the retentate. The permeate is enriched with organic vapors, while the retentate is purified light component gases. The main types of organic vapor separation membranes are spiral-wound and plate-and-frame membranes.

Features

- High recovery rate, typically above 90%
- Low equipment investment with short payback period (usually 3-12 months)
- Good operational flexibility (50-200%)
- No moving parts, ensuring low operational costs
- Primary energy consumption is due to the compressor
- Skid-mounted design for minimal space requirement
- Easy expansion and capacity increase
- Can be coupled with other processes
- Clean and environmentally friendly with zero emissions



Applications

- Recovery of propylene monomer from polypropylene production exhaust air
- Recovery of derivatives of propylene (e.g., acrylonitrile, butanol, propylene oxide)
- Recovery of ethylene, butene, pentane, hexane from polyethylene production exhaust air
- Recovery of ethylene derivatives (e.g., ethylene oxide, ethylene glycol, polyvinyl chloride)
- Recovery of chloromethane monomer in chemical products like organosilicon quaternary ammonium salts
- Recovery of light hydrocarbons from catalytic reforming and vent gases
- Recovery of vapors from tank truck loading and unloading
- Gasoline vapor recovery from gas stations and storage tanks
- Natural gas dew point control