METHOD FOR REDUCING THE CLOUD POINT OF MATERIALS USING AN ULTRAFILTRATION SEPARATION PROCESS

摘要

ABSTRACT OF THE DISCLOSUREA method is disclosed for reducing the cloudpoint of materials comprising the steps of chilling thewaxy oil so as to achieve submicron crystallizationfollowed by ultrafiltration thereby effecting separa-tion of a permeate of reduced cloud point from aretentate. Chilling to produce submicron crystalliza-tion is to a temperature about 3°C or less above thecloud point of the material, preferably from 0.5 to 2°Cabove the cloud point of the material, most preferablybetween 1 to 2°C above the cloud point of the material.In general, any mixture, solution or meltcontaining components which crystallize at differenttemperature can be separated by this procedure. Themethod is especially useful for reducing the cloudpoint of waxy hydrocarbon oils.The ultrafiltration membrane used will be onewhich is inert in and non-reactive with the componentsof the solution, mixture or melt, will not melt at thetemperatures employed, which possesses an effectivepore size smaller than the submicron crystals formedupon chilling and which does not have a strong chemicalaffinity for the crystallized component of the feedmixture, solution or melt.