Design of an integrated process for biodiesel production using supercritical methanolysis: Simultaneous work and energy integration

Biofuels have attracted a considerable attention as alternative replacement for fossil fuels in the last decades due to the depletion of crude oil resources and environmental concerns for greenhouse gases emission. Biodiesel has been recognised as a potential replacement for petroleum diesel fuel as it is a non-toxic, renewable and sustainable fuel. Recently, the use of supercritical methanolysis for biodiesel synthesis has been extensively reported due to its advantages over the conventional catalysed transesterification techniques. However, supercritical production process has some disadvantages including harsh reaction conditions, large excess of methanol and high energy consumption. Process energy integration has achieved notable success reducing the energy consumption for supercritical biodiesel processes. Work is considered as an equally effective thermodynamic parameter where transfer of heat and/or work affects the enthalpy of the process streams. Organic Rankine cycle (ORC) has been integrated to a supercritical biodiesel process to utilise the process excess heating energy to produce electricity. The integrated process has been compared with the conventional basic process for supercritical biodiesel production. It has been reported that the integrated process has provided lower net energy consumption in comparison with the basic process.