A novel solar reactive distillation based production of algal biodiesel: Retrofitting, carbon cost and process economics

Abstract

In this contribution, solar power driven reactive distillation based process is developed for the production of algal biodiesel. For industrial scale operation, the conventional reactive distillation (cRD) is designed to retrofit with a parabolic trough collector (PTC) that yields cRD-PTC based scheme. To serve the same purpose, we have subsequently proposed a solar reactive distillation based configuration. The optimal design and operating conditions of both processes are determined with two conflicting objectives: minimising the total annual cost (TAC) and maximising the purity of biodiesel. For this, the optimisation is performed by the technique for order of preference by similarity to ideal solution embedded non-dominated sorting genetic algorithm-II. Further, we evaluate those process units in terms of the emission trading system based carbon pricing (ETS-CP) and social cost of carbon (SCC) considering the availability of solar energy during day time only. The attractiveness of the proposed solar reactive distillation based process lies in its total annual cost savings of 9.92% (ETS-CP) and 19.06% (SCC), whereas they are 6.67% (ETS-CP) and 16.14% (SCC), respectively for the conventional reactive distillation coupled with parabolic trough collector (cRD-PTC) process. It is further investigated that the total annual cost savings comes down when the proposed configurations are operated with solar (2000 working hours/year) and thermal energy (6000 working hours/year) throughout the year. Finally, the economic feasibility of the biodiesel production processes is studied with the usage of solar heat for the entire operating time.