Denickling of fatty acid pitch
Unsaturated fatty acids are usually hydrogenated with a nickel catalyst. As a side reaction, nickel dissolves in the fatty acids and forms nickel soaps. On refining the crude fatty acid feedstock by distillation, these nickel soaps are enriched in the bottom fraction (pitch) to a concentration range of 2,500-5,500 ppm. With a heat value comparable to heavy fuel oil, the pitch has been used as fuel
