Biodiesel is a good substitute for petroleum and diesel. Because of the superior environmental protection performance, many countries are developing the renewable energy source. The raw material for biodiesel production normally is vegetable oil and animal oil. Vegetable oil including soya and rapeseed, scrap cooking oil in hotel and restaurant. Some living garbage, used plastic, old tyre can also be used to produce biodiesel.
Compared with traditional diesel, biodiesel has many advantages, like better lubricity, easy storage, easy transportation, good antiknock performance, sufficient combustion etc. At present, most countries in the world use 20% biodiesel blended with 80% petroleum diesel oil, which can be used in any diesel engine.
For the production process using oil, acid oil or waste oil as raw material, due to the variability of raw material quality, the most suitable process is batch transesterification or esterification process.
The batch production process has the advantages of low investment, flexible operation, suitable for various raw materials; the disadvantages including small scale, unstable product quality, high operation cost, low rate of defects.
At the same time, the environmental protection processing cost increased due to the purification and treatment of the material.
For the vegetable oil/ animal oil with high quality, the free fatty acids content is very lower (acid value is less than 0.5mgKOH/g), no side reaction occurs during the reaction, so alkaline catalysis is suitable.
The advantage is to simplify the product refinement and reduce the operation cost,
The disadvantage is the quality requirements of raw materials;