High efficiency process for producing alkyl fatty acid ester by acid catalysis and treatment procedure

Procedure high efficiency for producing alkyl esters of fatty acids by acid catalysis, which occurs in a reactor (5) tubular isothermal preferably arranged vertically with liquid methanol and fat from 50% to 100% free fatty acid and less than 1% moisture, residence time between 15 and 120 minutes and a molar excess fat methanol / material over the stoichiometric reactions in a stage of 12 to 18: 1 or in the reactions in two stages first 4-6: 1 (up to 5% FFA), and the second stage 30-80: 1. # is also directed to the treatment method of the reaction products by acid catalysis homogeneous comprising a phase separate light and a heavy phase, and reduce the methanol content of the light phase to a concentration between 33-50% by weight, preferably 33-45% prior to the neutralization of remaining catalyst.