Patent ID: 8540880

Claim:
A method of purifying a biodiesel feedstock, the method comprising the steps in the order recited: (a) filtering a biodiesel feedstock, thereby separating from the feedstock solid particles having a diameter up to 2 microns, to provide a filtrate and a retentate; (b) separating water from the filtrate, to provide a dried filtrate; (c) distilling the dried filtrate, to provide a distillate and a residue; (d) distilling the distillate to provide a subsequent distillate and optionally a subsequent residue; and; (e) passing the subsequent distillate through an ion exchange resin to obtain a purified biodiesel feedstock; wherein the biodiesel feedstock comprises at least one of edible oils, inedible oils, fats, greases, brown grease, trap grease, used cooking oil, used cooking fat, animal fat, animal grease, and fatty acid distillate; and wherein the following are substantially separated from the biodiesel fuelstock in steps (a) through (e), as present; sulfur, phosphorus, gums/lipids, sterols, calcium, magnesium, iron, copper, cobalt, manganese, nickel, sodium, potassium, chlorophyll, carotenoids, xanthophylls, proteins, carbohydrates, aldehydes, ketones, carboxylic acids, perchloroethylene, polyaromatic hydrocarbons, polychlorinated hydrocarbons, polymerized triglycerides, pesticides, soaps, detergents, sulfonates, sulfates, phosphatides, phytosterols, sitosterols, cholesterol, and sterol glucosides.