Of the five natural gas liquids (NGLs), isobutane stands apart in its sources and markets. Isobutane comes from gas processing plants and refineries, but it is also the only NGL intentionally made from another NGL – it’s cousin, normal butane. It has a variety of exotic uses, such as aerosol propellant for everything from hair spray, to cooking sprays to shaving cream and since the early 90s as a replacement for Freon in refrigerators. A refinery process called alkylation is the largest market for isobutane, producing a high-octane gasoline blending component called alkylate. Even though it has robust markets, isobutane supply/demand balances are not immune to the growing volumes of high-BTU, “wet” shale gas and the resulting torrent of NGL production. And as gas plant isobutane volumes increase, there are changes coming to isobutane balances and the demand for merchant isomerization. Today we begin our series on isomerization by exploring what it is, why it’s valuable, and how it’s done.
