Coagulation and Ultrafiltration: a Hybrid Process for Purification of Used Engine Oils

The article presents experimental studies of the hybrid process of regeneration of used oils based on two interrelated processes of coagulation and ultrafiltration. The hypothesis that the process of coagulation due to aggregation of particles and organic substances contributes to the formation of a more porous sediment layer, which reduces pore blockage and increases filtration efficiency, has been checked. The aim of this study is to determine the most effective parameters of the baromembrane process by describing changes in the properties of deposits in a tubular ceramic membrane during ultrafiltration of waste oils. At the first stage, experiments were carried out on a Jar reactor with two different coagulants: an aqueous solution of diaminomethanal and a mixture of ethanolamine and propane-2-ol, and the effect of coagulants on the process of flake formation has been investigated by micrography of droplet samples and paper chromatography. At the second stage, studies of the ultrafiltration process have been carried out. Coagulation and ultrafiltration experiments have shown different permeability of the process. The effect on the permeate flow depends on the nature and composition of the coagulant. As a result of experiments, it has been shown that more stable flakes are formed under the influence of an aqueous solution of diaminomethanal and, as a result, a longer operation of the membrane element without a drop in permeability is observed.