METHOD OF PRODUCING FATTY ACIDS FROM VEGETABLE OIL SOAP STOCKS Russian patent published in 2025 - IPC C11B11/00 

FIELD: oil and fat industry.

SUBSTANCE: method of producing fatty acids from vegetable oil soap stocks, characterized by that, first, alkaline saponification of hydrated vegetable oil is carried out with sodium hydroxide solution with concentration of 30-45% for 240 minutes at temperature of 90-95 °C to pH 10-11 while stirring with steam under pressure of up to 0.2 MPa to obtain a soap glue with excess alkali content of 0.2-0.3%, then the obtained mass is subjected to salting-out with sodium chloride with concentration of 16-20% for 75-80 minutes, after which the obtained mass is settled for 2 hours and divided into three layers – lower – soap alkali, middle – adhesive soap, upper – soap core; soap core is decomposed with sulphuric acid in two steps: at the first stage – sulphuric acid with concentration of 10-12% at hydrolysis temperature of 110-115 °C for 40 minutes and on the second – sulphuric acid with concentration of 80-92% at decomposition temperature of 90 °C for 85 minutes to pH 2.0-2.5, wherein sulphuric acid is fed in portions while stirring with live steam under pressure of 0.3 MPa until complete decomposition of soap. After separation of second sulphate water, obtained fatty acids are washed with water condensate until complete absence of sulphuric acid and sodium sulphate.

EFFECT: invention increases output of fatty acids, improves environmental situation by reducing waste water discharge, reduces energy consumption for obtaining fatty acids from vegetable oil soap stocks and reduces consumption of sodium hydroxide and sulphuric acid.

1 cl, 2 tbl