(21a) Novel Reverse-Selective Membrane for Refinery Applications

Over the last decade MTR has successfully developed and commercialized an innovative "reverse-selective" membrane. This membrane preferentially permeates the larger, more condensible hydrocarbon components over the smaller, lighter compounds. To date the largest use of these membranes has been for petrochemical applications, most notably in olefin and nitrogen recovery from polyolefin vent streams. However, this innovative membrane is also an attractive solution for treating various refinery streams. Refineries produce a variety of purge streams from hydrotreating and other cracking/conversion processes. These streams, while containing valuable compounds are too dilute for direct reuse, and therefore are typically used as fuel or flared. Traditionally a size-selective membrane has been used to treat these purge streams, primarily to recover hydrogen. However, in some situations the conventional hydrogen membrane is not suitable, particularly when retrofitting an existing hydroprocsssing unit with limited compression capacity. In addition, the size-sieving hydrogen membrane does not perform well when treating low-pressure, low concentration hydrogen streams, such as fuel gas streams. In contrast, MTR's membrane offers an innovative and economic solution capable of providing hydrogen enrichment as well as the potential to recover C3+ hydrocarbons valuable LPG.