Apparatus and systems for improved alkyl ester production from feedstocks containing organic acids using low pressure alkylation

An apparatus or system for preparing an organic acid alkyl ester from a feedstock comprising an organic acid and one or a plurality of saponifiable compounds, the apparatus or system comprising:

• a first reactor or stage, a second reactor or stage and a third reactor or stage,
• wherein the first reactor or stage is operatively connected to the second reactor or stage, and the second reactor or stage is operatively connected to the third reactor or stage,
• wherein the first reactor or stage is configured for a first reaction process operating under conditions comprising:
• (a) providing or feeding in at least one alkylating reagent,
• (b) a temperature of between about 100° C. to 400° C. and pressure of between about 0.1 barg to 355 barg, for esterifying and/or transesterifying the feedstock containing organic acid with the at least one alkylating reagent,
• wherein the first reactor or stage is configured to substantially remove the at least one alkylating reagent and glycerin, if glycerin is formed from transesterification of the feedstock, and
• (c) up to 5 wt % moisture, or between about 1 wt % and 10 wt % moisture, the moisture originating from the second reactor, with or without catalyst, to reduce the acid value to about 100 or less, thereby generating the organic acid alkyl ester, which is fed into the next, or second reactor or stage;
• and
• wherein the second reactor or stage is configured for operating under conditions comprising at least about 0.1 barg above the first reactor or stage for further reducing the acid value of the organic acid alkyl ester fed in from the first reactor to about 40 or less, or reducing to an acid value of between about 1 and 10, by utilizing or feeding into the reactor excess alkylating reagent, or a molar excess of alkylating reagent as compared to organic acid alkyl ester, containing up to 1 wt % moisture, or between about 0.5 wt % and 5 wt % moisture, originating or fed in from the third reactor or stage, thus generating additional organic acid alkyl ester, which is fed into the next, or the third reactor or stage;
• and
• a third reactor or stage configured for generating and operating under conditions comprising least 0.1 barg in pressure above the second reactor or stage for further reducing the acid value of the organic acid alkyl ester fed in from the second reactor or stage to about 20 or less, or reducing to an acid value of 18, 15, 12, 10, 8, 5 or 2 or less, by utilizing excess alkylating reagent, or a molar excess of alkylating reagent as compared to organic acid alkyl ester, wherein the excess alkylating reagent has been substantially separated from water, or water and glycerin, that originates from the first reactor or stage,
• wherein apparatus is configured such that the feedstock and organic acid alkyl ester flows from the first reactor or stage to the second reactor or stage to the third reactor or stage;
• wherein apparatus is configured such that the at least one alkylating reagent can flow from third reactor or stage to the second reactor or stage to the first reactor or stage, wherein the at least one alkylating reagent is purified or substantially purified to remove water and/or glycerin, then the alkylating reagent is combined with fresh makeup alkylating reagent to flow back to third reactor or stage.