BenzSep is a proprietary membrane pervaporation process that selectively removes only benzene (close to chemical grade) from streams such as reformate or FCC naphtha, while leaving toluene and xylenes in the feed, thereby minimizing octane loss. This process also works for selective removal of benzene from pyrolysis gasoline ("PyGas"), a by-product of steam cracking of naphtha for olefins production.

What sets BenzSep apart from other pervaporation processes is the unique and patented use of a Venturi nozzle and special working fluid with which to pull the vacuum required to recover permeate from the downstream side of the membrane and replace more costly and less efficient steam ejectors or vacuum pumps used by other manufacturers for this purpose. The figure below shows the simplicity of the overall process.

Benzene is recovered from the Venturi liquid at atmospheric pressure thus eliminating expensive refrigeration systems generally required to condense light hydrocarbons at high vacuum. This reduces both capital and operating costs substantially over conventional pervaporation systems that use vacuum pumps (or steam ejectors) and refrigeration units.

Membranes used in BenzSep are well understood polymers that have demonstrated high selectivity for aromatics in previous testing and that can operate easily in the 80 - 100 °C range for maximum flux.