Case Study: Fuel Gas Recovery From Polyethylene Purge Bin Offgas

Client's Problem:

The client has two PE plants that yield purge bin offgases that are currently being burned in the flare. The offgases contain 30- 40 mol% of nitrogen, giving too low a BTU value for the gas to be used as fuel in the plants. The client is flaring valuable hydrocarbons which could be used elsewhere in the plant. 

MTR's Solution:

The client has ordered two VaporSepÆ systems from MTR. These will be installed at the PE plants and will remove most of the nitrogen from the offgases. With less than 10% nitrogen, the treated offgases will then be used as high quality fuel gas in each plant. Both VaporSepÆ systems are similar in design and include an oil-flooded screw compressor package, an after-cooler, and a membrane unit.

One of the systems is designed to treat 3.5 tons/hr, and the other system is designed to treat 4.6 tons/hr. Each system will recover more than two tons/hr of fuel gas. Both systems will be delivered in early 2010.

Membrane Technology and Research, Inc. 39630 Eureka Drive, Newark, CA 94560 • (650) 328-2228