Middle and low temperature preparation method for biological diesel oil by using plants fruits and seeds oil and special-purpose distillation tower for the same

The invention discloses a process for preparing biological diesel oil through utilizing plant fruit seed oil in medium-low temperature and specific distilling tower. The process for preparation comprises following steps: adding raw oil, benzene sulfonic acid and auxiliary agent into an esterification reaction still, heating, then, continuously adding carbinol to generate esterification reaction, the raw oil which is after the esterification reaction is cooled and preserved heat, then adding carbinol, simultaneously, slowly dropping sodium methoxide, generating the esterification reaction, inputting the compound which is after the esterification reaction into a separating tank, separating out coarse biological diesel oil and coarse glycerin, inputting the coarse biological diesel oil into the specific distilling tower to distill and separate, and inputting the biological diesel oil and plant asphalt into respective storing tank. The specific distilling tower comprises a heating chamber, a gas chamber and a res