Function and Performance of a Pre-Reactor to a Reactive Distillation Column for Biodiesel Production

This article describes an in-depth follow-up to previous studies showing that an oil-methanol mixer prior to an RD reactor played an important role in enhancing the overall performance of the RD reactor system. An in-line static mixer was used for the purpose of providing initial mixing of the reactants, heating the mixture up to the desired operating temperature, and carrying out a substantial part of the transesterification reaction in the early stage. It performed three functions: a reactant mixer, a heat exchanger, and a pre-reactor. This article reports the systematic investigations of the pre-reactor performance by examining the effects of process variables on the process evaluating parameters, and the operating conditions for optimum operation. A wide range of results was observed under different operating conditions. The product yield was as high as 84.60% and as low as 1.63%. The soap formation was in the range of 2.80% to 10.37%. The feed molar ratio, reaction time, and catalyst concentration all contributed positively to the product yield and soap formation. Although an optimum condition produced a product yield of 80.46% and soap formation of 5.18% with a 1.33 min reaction time, the optimization should be based on the integration of the whole RD reactor system rather than a collection of individually optimized components. This study of the pre-reactor serves as an analysis tool for part of the RD reactor system.