EXTRACTIVE SEPARATIONS FOR POLAR COMPOUNDS FROM HYDROCARBONS
Hydrocarbon Streams are contaminated by soluble polar (or ionic) contamination in a variety of ways (viz., caustic treatment, amine treatment, acid catalysts etc). The contaminant typically exists within the hydrocarbon phase in a soluble form, and in some cases it may not even be ionized within the non-polar hydrocarbon. Nevertheless, it is generally necessary to remove these contaminants. In some cases, the contaminants may poison downstream process equipment; or example, diesel fired turbines are sensitive to alkali metal contaminants; selective hydrogenation units (SHU) are sensitive to sodium). In other cases, these soluble contaminants represent an ongoing operating cost (i.e., amine dissolved in a C3/C4 stream needs to be made up with fresh (expensive) amine).
Conventional Approaches to removing the dissolved polar components, utilize washing the hydrocarbon with water. Typical approaches involve:
- Water-Wash Towers
- Water Injection followed by Coalescer or Knock-Out
Polarex, US Patent 8425663, an extractive separations technology provides gas processors, chemical manufacturers, and refiners dramatically improved separation of entrained and dissolved contaminants. It is designed to replace conventional water wash and solvent scrubbing towers.
The patented Polarex technology may be applied to the extraction of soluble components from either liquid or gas process streams. It has application to both contaminant removal (e.g. - caustic, dissolved acids, salts, acid gases or reaction by-products) as well as recovery of valuable products or solvents (e.g. – recover soluble amines from treated LPG or recovery of LPG from high BTU natural gas streams) for as little as 20% of the capital associated with a conventional system. It has already been successfully installed in several NGL treating applications (displacing conventional amine contactors) with staggering results of 86% of operational time above nameplate capacity and 19% above design while maintaining treating efficiency.