The invention relates a kind of preparation method of bio-diesel oil under the condition of
solid ac and alk catalyzing. The character is that under the condition of
solid ac and alk catalyzing,
gain the bio-diesel oil using the craft of exchange reaction of soja oil with carbinol. Afer the reaction, apart catalyser from reaction liquor by centrifugal
machine till delimination in quiet placing, the above is rough output, the below is admixture of
glycerol and carbinol. Distil the of above to
gain bio-diesel oil and to
gain the pure glycerin in the same way. The distilled carbinol can be used again and again. The invention has many advantages, for example, its
raw material can be rebirth, its craft is easy and only need normal equipment. Even treat the used oil, the whole process is easier compared with the method in
solid ac and alk catalyzing, besides, the process will not produce foul water so it is environmental. Every
plant of the bio-diesel accords with standards compared with
foreign similar competitive grade and the main plants are close to its of 0# (GB252-1994, superior product)diesel of China.