The whole idea of PI can be generally classified as process-intensifying equipment and process-intensifying methods as shown in Fig. 1. The biodiesel production technologies developed based on the PI concept focus on shorter reaction time but high conversion, low molar ratio of alcohol to oil, low catalyst concentration and most importantly, lower operating cost and energy consumption for biodiesel purification, and recovery of glycerol, catalyst and excess alcohol. Furthermore, these technologies also allow feedstock flexibility and rapid reaction permitting continuous production and separation of the reaction products. Eventually, this gives efficient recovery of catalyst, high product yield and quality as well as a reduction in environmental impact.