An evaluation of the evaporation rate of crude oil on voyage is one of the most important factor in designing the tank venting system of the crude oil tankers. The author gave some theoretical considerations on evaluation of the evaporation rate of crude oil: one is the macroscopic evaluation from the viewpoint of the energy conversion method and the other is the microscopic evaluatioon from the viewpoint of the transfer phenomena method. The results obtained from these theories agree well with the experimental results.
