Novel Membrane Pervaporation Process Removes Sulfur from Gasoline

TranSep™ is a revolutionary pervaporation process that selectively separates the aromatic molecules (containing most of
the sulfur) from gasoline streams without also removing the olefins, thereby allowing the high-sulfur product to be
nonselectively hydrotreated without significant loss in octane. What sets TranSep™ 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. The figure below shows the simplicity of the
overall process.

Permeate 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 the capital and operating costs
substantially over conventional pervaporation systems that use vacuum pumps (or steam ejectors) and refrigeration units.