Butene-1 production normally requires two very large fractionation columns and significant amounts of energy to achieve desired separation due to similar boiling points. SK-KBR Technologies provides a novel adsorption/desorption process, Ole-SIV, for the economic recovery of Butene-1 from mixed C4 streams. The Ole-SIV technology can significantly reduce total investment cost (by up to 30%) and energy consumption (by 20-40%) over conventional fractionation systems.
Butanes and various butenes comprise half of a naphtha C4 stream. Although they are valuable, most butenes are blended to mogas due to difficulties in separating them from the C4. Butene-1, for example, has high commercial value as polyethylene (LLDPE) co-monomer and is conventionally extracted from a C4 stream by distillation. However, the industry-leading distillation process still requires two tall columns with as many as 200 theoretical trays. Ole-SIV is an innovative alternative process that effectively separates butenes from paraffins by adsorption. The proprietary Ole-SIV adsorbent traps C4 olefins while C4 paraffins pass through. The adsorbate is periodically purged to produce butene-1 and -2, which are later separated in small distillation columns.
The Ole-SIV process contains two major stages: Adsorption and Desorbent Recovery. C4 mixtures of olefinic and paraffinic hydrocarbons enter the Adsorption stage where olefins are adsorbed on the adsorbent. Adsorption produces two product streams: raffinate and extract. The extract stream includes olefins with desorbents, while the raffinate stream has paraffins with desorbents. These two streams from Adsorption are processed in the Desorbent Recovery stage with two small distillation columns, respectively. Desorbent Recovery produces highly pure paraffin and olefin products at high yield rates, and the recovered desorbent is recycled to the Adsorption stage.