Energy Integration and Optimization of the Separation Section in a Hydrotreating Process for the Production of Biojet Fuel

Abstract In the transport sector, aviation has a strong growing, expecting an annual increase of 5% with respect to other transport ways. If fuel consumption grows at the same rate, CO 2 emissions due to worldwide aviation in 2050 would be more than six times of the current value. The International Civil Aviation Organization has recognized sustainable alternative fuels, such as biojet fuel, as an important pillar to strategically reduce greenhouse gas emissions from aviation. There are several pathways potentially suitable to produce biojet fuel. Nevertheless, the hydrotreating process is one of the most promissory; its main challenges are the reduction of the investment and operation cost, along with the selling price of biojet fuel. Thereby, in this work the modelling and optimization of the separation zone of the hydrotreating process for the production of biojet fuel are presented, considering Jatropha Curcas oil as renewable raw material. In the separation zone four distillation schemes are considered; two conventional and two intensified options. They were optimized by a multi-objective genetic algorithm accelerated by neuronal networks; generating a Pareto front for each scheme, showing the better trade-off between the two objectives: number of stages and reboiler duty. For each scheme a point from the Pareto front is selected, which is integrated to the reactive zone of the previously modeled process in order to estimate the energy released for the whole process. The results show that it is possible to satisfy some of the energy requirements of the purification zone through energy integration. Also, the process with the direct conventional distillation sequence has the lowest energy consumption; having a direct impact on the cost of biojet fuel, which results competitive with that of the fossil jet fuel.