PROCESS FOR PRODUCING BIODIESEL FUEL, DEVICE FOR RESIDUAL-ALCOHOL REMOVAL FOR USE THEREIN AND DEVICE FOR PRODUCING BIODIESEL FUEL

摘要

PROBLEM TO BE SOLVED: To provide a process for producing a biodiesel fuel, in which none of much energy cost, a long-time treatment, and a large-scale device is required for removing, to a high level, the alcohol, free glycerin, alkali metal, etc. that remain in a light liquid (crude biodiesel fuel) separated from the liquid reaction mixture resulting from transesterification in biodiesel fuel production steps; and to provide a device for residual-alcohol removal and a device for biodiesel fuel production which are for use in this process.SOLUTION: A process comprises a reaction step in which raw fats or oils are brought into contact with an alcohol in the presence of an alkali metal catalyst to conduct transesterification, a separation step in which the liquid reaction mixture from the reaction step is gravitationally separated into a light liquid and a heavy liquid, and an alcohol removal step in which the light liquid from the separation step is heated to remove the residual alcohol from the light liquid. In the alcohol removal step, the light liquid is brought into gas-liquid contact with a gas for recovery to thereby remove the residual alcohol from the light liquid and recover the residual alcohol in the gas for recovery.