Catalytic purification of fatty acid alkyl esters used in fuels

A process comprising:

• (a) introducing triglyceride-containing feedstock and an alcohol as reactants into a reactor selected from the group consisting of continuous fixed bed reactor, a continuous tank reactor, and a batch reactor,
• (b) contacting the reactants in the reactor with a catalyst in liquid, granulated or powder form;
• (c) subjecting the feedstock and catalyst to transesterification conditions sufficient to convert triglycerides to products comprising alkyl ester derivatives of the triglycerides, and glycerin, wherein the alkyl ester derivatives of the triglycerides and impurities are present in an oil phase, and glycerin is present in a water soluble phase;
• (d) performing product separation to remove glycerin product from the oil phase;
• (e) contacting the oil phase separated by (d) and, optionally, any residual unreacted alcohol, with a catalyst and, optionally, additional alcohol, under catalytic conditions to convert the impurities in the feedstream to a product or by product, and
• (f) recovering a fatty acid alkyl ester stream having reduced amounts of impurities.

A process comprising:

• (a) introducing triglyceride-containing feedstock and an alcohol as reactants into a reactor selected from the group consisting of continuous fixed bed reactor, a continuous tank reactor, and a batch reactor,
• (b) contacting the reactants in the reactor with a catalyst in liquid, granulated or powder form;
• (c) subjecting the feedstock and catalyst to transesterification conditions sufficient to convert triglycerides to products comprising alkyl ester derivatives of the triglycerides, and glycerin, wherein the alkyl ester derivatives of the triglycerides and impurities are present in an oil phase, and glycerin is present in a water soluble phase;
• (d) performing product separation to remove glycerin product from the oil phase;
• (e) removing residual alcohol from the oil phase recovered in (d),
• (f) contacting the oil phase with adsorbent or filter, and
• (g) further contacting the alkyl ester-containing oil phase recovered from (f) and any impurities therein with a catalyst and, optionally alcohol, under catalytic conditions to convert impurities in the alkyl ester-containing oil phase to a product or by product, and
• (h) recovering a fatty acid alkyl ester stream having reduced amounts of impurities.

A process comprising:

• (a) introducing triglyceride-containing feedstock and an alcohol as reactants into a reactor selected from the group consisting of continuous fixed bed reactor, a continuous tank reactor, and a batch reactor,
• (b) contacting the reactants in the reactor with a catalyst in liquid, granulated or powder form;
• (c) subjecting the feedstock and catalyst to transesterification conditions sufficient to convert triglycerides to products comprising alkyl ester derivatives of the triglycerides, and glycerin, wherein the alkyl ester derivatives of the triglycerides, and impurities are present in an oil phase, and glycerin is present in a water soluble phase;
• (d) performing product separation to remove glycerin product from the oil phase;
• (e) subjecting the oil phase to further transesterification in one or more reactors with additional alcohol under conditions sufficient to convert triglycerides, diglycerides and monoglycerides to products comprising alkyl ester derivatives of and optionally glycerin;
• (f) recovering the alkyl ester derivatives in an oil phase with one or more product separation steps;
• and
• (g) contacting the recovered oil phase comprising alkyl ester derivatives, and any impurities therein and unreacted alcohol, with a catalyst and, optionally, additional alcohol, under catalytic conditions to convert the impurities in the feed stream to a product or by product, and
• (h) recovering a fatty acid alkyl ester stream having reduced amounts of impurities.