| Four typical biodiesel production processes were listed and compared based on the application practices of the novel technologies developed in a decade continueously in biodiesel industry. The acid catalysis under pressure method had the items of medium investment, long reaction period, 85%-90% of product yield, relatively higher comprehensive energy consumption and production of acidic waste water and waste gas; novel type catalyst and gas phase esterification method had the items of above 90% of product yield, low comprehensive energy consumption, less waste water and production of waste gas; hydrolysis and immobilized bed acidification method had the items of relatively higher investment, wide adaptability of raw materials, stable product quality, less emission of waste water and waste gas, simultaneous production of mixed fatty acids and high value-added products, relatively higher comprehensive energy consumption and above 92% of product yield, and the integrated product costs significantly decreased if considering high value-added products; immobilized enzyme catalysis method had the items of low investment, poor adaptability of raw materials, low reaction temperature, low comprehensive energy consumption, no emission of three wastes and continuous production. Some enterprises generalised the production of biodiesel using immobilized enzyme catalysis method abroad, while the technology transfer was immature in China. |
