Patent ID: 7666234

Claim:
A process comprising: (i) Treating a plant material to expel an oil therefrom while obtaining a cake of residual plant material; (ii) Treating the expelled oil with an alkali to neutralize excess free fatty acid in the expelled oil and separating a soap cake so formed; (iii) adding an antioxidant to the treated oil and sparging the treated oil with alkali, and separating out soap cake; (iv) treating the sparged oil with an appropriate quantity of methanolic-KOH solution dried with anhydrous sodium sulphate to obtain a glycerol layer and a fatty acid methyl ester layer; (v) separating the glycerol layer formed during the treatment in step (iv); (vi) treating the fatty acid methyl ester layer with glycerol in two lots to further reduce methanol, catalyst and other impurities in the fatty acid methyl ester layer; (vii) separating the glycerol layers obtained in step (vi); (viii) washing the fatty acid methyl ester layer obtained in step (vi) with water in two lots to reduce impurities; (ix) separating the aqueous washings; (x) adding an additional quantity of antioxidant to the fatty acid methyl ester and sparging with dry air to reduce moisture content, to obtain the fatty acid methyl ester; (xi) collecting the glycerol layers and treating the collected layers with SO x or flue gas to convert spent KOH catalyst therein into K 2 SO 4 or K 2 CO 3 , respectively; (xii) adjusting pH and distilling off methanol contained in the glycerol layers; (xiii) hot centrifuging a remaining mass to separate out potassium salt from the glycerol; (xiv) washing said salt to substantially remove adhering impurities therefrom; and (xv) keeping aside a required amount of crude glycerol for washing a fatty acid methyl ester layer of a subsequent batch, and optionally also keeping aside a further required amount of the crude glycerol, and distilling the remaining crude glycerol having a low water content to produce therefrom refined, neat glycerol.