The simplest definition of an oleo chemical is a chemical produced from natural oils and fats. Of the 105 million tons or so of fats and oils produced worldwide, every year, about 80% is utilized for human food. About 5% is consumed as part of animal feeds and about 15% is used to produce chemicals. About 16 million tons finds its way into the chemical industry, usually in the form of coconut oil, palm kernel oil, palm oil and tallow (animal fat). These oils fall into two groups - lauric oils (coconut and palm kernel) that are rich in carbon chains consisting of 12 and 14 linked carbon atoms, and those with carbon chains of 16 and 18 carbon atoms (tallow and palm).figure (1) shows raw materials and basic oleo-chemical from it.
Oleo chemical is considered to be alternative to petrochemical and like it we first produce basic chemicals then derivatives from it.
At first crude oil is washed with water in a plant called “fats depuration” to remove all impurities which is soluble in water , while that is not soluble “like gums and gossypol” is get rid of in a plant called “bleaching” where crude is washed with “phosphoric acid” and pass through a mesh filter.
Looking at the structure of oils and fats we can find that the main constituent is triglyceride.
The first main process in oleo chemical is splitting i.e. the reaction of the triglyceride with water that produces glycerol and fatty acid. As water and oil don’t mix, we were obliged to raise temperature of the reaction to 230 0 c and the pressure to 30 bar.
Obtaining two separated phases i.e. to products so we will have to routes, the first is “sweet water”. As splitting reaction is done with excess of water, we direct “sweet water” to evaporator where we get rid of water and raise glycerol concentration to nearly 90 %. This 90% concentrated glycerin is fed to glycerin unit, using vacuum distillation to get high grade glycerin and also second grade glycerin. This process is done nearly below 100mbar absolute.
Second stream i.e. fatty acid is sent to fractioning unit usually operating p is between 10mb to 50mb and T between2200 C to 2700 C. This fatty acid may go to saponification unit to produce high quality soap noodle.
Latest advanced oleo-chemical plants have hydrogenation unit, this unit can be used for both fatty acid and for crude oil. This is a short introduction on oleo-chemical plant that can be enhanced by further reading.