As a precursor of the practical catalyst to utilize solid base catalysis of calcium oxide for biodiesel production, crushed lime stone whose size ranged from 1.0 to 1.7 mm was used in this study. The precursor was turned into the practical catalyst by only calcination at 1173 K. At 333 K under atmospheric pressure, rapeseed oil was transesterified with methanol in the presence of the practical catalyst, on a laboratory scale pilot plant characterized by batch unit consisting of a circulating stream passing through the column reactor. In the early trial, the yield of fatty acid methyl esters (FAME) produced after 2 h was around 60%. Moreover, the column reactor was blocked up due to serious agglomeration of the practical catalyst when the reaction time was extended by an extra hour. These drawbacks were hurdled by improving the reacting condition. As a result, the yield of FAME reached 96.5% at 2 h of the reaction time, and the good reaction efficiency went on for the successive 10 operations, without exchanging the catalyst. However, on and after the 11th operation, the reaction efficiency was gradually deteriorated. After the transesterifying operation was successively repeated 17 times, the practical catalyst was withdrawn from the column reactor in order to investigate its deactivation. Additionally, the transesterification of waste cooking oil was performed on the laboratory scale pilot plant in the same manner. (c) 2009 Elsevier Ltd. All rights reserved.