Low pour point transformer oil from paraffinic crude - by fractionation, solvent extraction and solvent dewaxing in three-phase system

摘要

Prodn. of transformer oil with a low pour point (below-40 degrees F) from a waxy distillate fraction of a paraffinic crude comprises first subjecting the distillate, which has a 5-95% boiling range of 595-755 degrees C (pref. 600-735 degrees F) at atmospheric pressure, to solvent extraction to produce an extract and a raffinate. The raffinate is then subjected to solvent dewaxing at -10 to -40 degrees F (pref. -20 to -30 degrees F) to form a 3-phase slurry contg. solid wax, an oil-rich liq. phase and a solvent-rich liq. phase. The slurry is filtered at -10 to -40 degrees F (pref. -20 to -30 degrees F) to separate the solvent-rich pha se as filtrate from a wax cake contg. the oil-rich phase. The solvent is then removed from the filtrate to recover the transformer oil. The process avoids the use of special fractionating columns and gives products with a low cloud point (e.g. -23 to -29 degrees F).