This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
One may partially or completely deodorize and decolorize rank fish and other oils by sending a current of hot air or of steam through them, after having heated them from 175° to 200° F. To decolorize palm oil pass through it a current of steam under pressure corresponding to a temperature of 230° F., agitating the oil constantly. The vapor is then passed through leaden tuyeres of about 2 inches diameter, 10 hours being sufficient for deodorizing 4 tons of oil.
Another method that may be applied to almost all kinds of fats and oils with excellent results is the following: Melt say 112 parts, by weight, of palm oil in a boiler. When the mass is entirely liquefied add to it a solution of calcium chloride, made by dissolving 7 parts, by weight, of lime chloride for every 84 parts, by weight, of oil in water, and mix intimately. After cooling, the mass hardens and is cut into small bits and exposed to the air for a few weeks. After this exposure the material is reassembled in a boiler of iron, jacketed on the inside with lead; a quantity of sulphuric acid diluted to 5 per cent, equal in amount to the lime chloride previously used, is added, and heat is applied until the oil melts and separates from the other substances. It is then left to cool off and solidify.