(1) Physical degumming: first of all, using oil hydration or phosphoric acid-etching method, remove the phospholipids and colloid and other substances, and then preheating, dehydration the oil.
(2) Methanol esterification: adding excess methanol into the raw oil material, with the acid catalyst, conduct pre-esterification, changing free acid into methyl ester.
(3) Continuous ester exchange: the pre-esterification oil together with methyl alcohol, adding little NaOH as catalyst, under a certain temperature and atmospheric pressure, conduct ester exchange, then get methyl ester.
Using two-step reaction, through a specially designed separator continuously eliminate the glycerin engendered in the reaction, make the ester exchange continuously.
(4) Gravity precipitation, water washing and stratification.
(5) Glycerol separated from crude methyl ester.
(6) Biodiesel refined.
The whole process is closed-circuit circulation, all raw material comprehensive utilization, cleaner production. Roughly described as follows:
Raw material pretreatment (dehydration, deodorization, purification )-----the reaction kettle (methyl ester+ alcohol catalyst + 70°C) -----stirring reaction N hours----precipitation separation line of mixed alcohol----methyl distillation----recovery of alcohol----methyl ester distillation----finished product.
What is the advantages of biodiesel?
Engine is starting at low temperature(-10C).
It not belongs to dangerous cargo, so it's easy to transport.
There is less sulfur and aromatic alkyl in biodiesel, so it's less harmful to human and environment.
As a kind of renewable energy sources, the biodiesel will not finised.
The supply of biodiesel is not controlled by OPEC, it's benefit to the stability of international petroleum market.