Natural Gas Sweetening – MEDAL membrane (CO2 removal) Process by Air Liquide

Selectively removing carbon dioxide (CO2) and water (H2O) vapor from raw natural gas or associated gas to meet pipeline specifications for both onshore and off-shore locations. Upgrade low Btu gas (e.g., landfill gas) for fuel. Debottleneck existing solvent based CO2 removal systems. Recover valuable hydrocarbons from enhanced oil recovery floods for CO2 reinjection.

Product: Purified natural gas, predominantly methane, meeting pipeline specifications; high Btu fuel gas; high-purity CO2 for reinjection.

Natural Gas Sweetening - MEDAL membrane (CO2 removal) Process by Air Liquide

MEDAL natural gas membrane modules are made up of millions of hollow-fiber membrane filaments. The hollow fibers are assembled in a patented radial cross-flow permeator. Modules are combined in pressure vessels to provide maximum system performance and to minimize space requirements.

The feed stream (from which CO2 needs to be removed) passes over the membrane module feed chamber at high pressure. Carbon dioxide, H2O vapor and hydrogen sulfide (H2S) pass through the membrane from the high-pressure chamber to the lowpressure chamber (the permeate). Methane, ethane, nitrogen and other hydrocarbons are enriched into high-pressure residual gas.

Typically, a two-stage design is used to limit the hydrocarbon losses to less than 1%. In a single stage, between 2% and 5% losses are typical. Typical feed rates vary from less than 1 million scfd to as high as 1,000 million scfd with CO2 content varying between 3% and 70%. Typical feed pressure varies between 100 to 1,500 psig.

MEDAL natural gas membrane units are simple to operate and have no moving parts, thereby requiring minimum maintenance. Additionally, the membrane units are modular, enabling easy expansion—making them the ideal choice for remote locations.

Economics: Typical processing cost for CO2 removal using MEDAL natural gas membranes varies between $0.05 and $0.15 per 1,000 scf of feed gas depending on feed composition, temperature and pressure.

Licensor: Air Liquide S.A. (MEDAL, L.P.)


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