Investigation of the kinetics of three-stage processing of vegetable oil coapstocks

The aim of the study is to identify the kinetic patterns of a three-stage technology for obtaining fatty acids from soapstocks, including alkaline saponification of hydrated vegetable oil, desalination with sodium chloride, hydrolysis and decomposition of the soap core with sulfuric acid, as well as washing of the obtained fatty acids. The kinetic patterns of each of the three stages of soapstock processing were investigated. The hydrated vegetable oil was subjected to alkaline saponification with a sodium hydroxide solution with a concentration of 30-45% in an amount of 15% by weight of the raw material for 240 minutes at a temperature of 90-95 ° C with stirring until a soap glue was obtained. It was found that the duration has a greater effect on the acid yield than the concentration of the sodium hydroxide solution. Increased saponification time from 60 to 240 minutes. increases the yield of fatty acids by 1.58 times. The resulting saponified mass was salted with sodium chloride at a concentration of 16-20 % for 75-80 minutes at boiling point and constant mixing. The rational salting conditions were determined: duration (80 min.) and concentration of sodium chloride (20%). The resulting soap core was decomposed with a solution of sulfuric acid in two stages: in the first stage, with sulfuric acid with a concentration of 10-12% at a hydrolysis temperature of 110-115 ° C for 40 minutes; in the second stage, with sulfuric acid with a concentration of 80-92% at a decomposition temperature of 90 ° C for 85 minutes, stirring the mass until the soap completely decomposes. The resulting fatty acids had a significantly lower mass fraction of moisture and volatile substances and an increased cleavage depth.