Environmental regulations show more and more focus on reducing the effects of using fossil fuels. The aviation sector's commitment to society has led to the development of the process to replace these fuels with fuels from renewable sources. The design of these processes must be aimed at being efficient, profitable, and environmentally friendly. Bio-jet fuel is a fuel that can be obtained by different technological routes. The process of converting alcohol to bio-jet fuel known as ATJ (alcohol to jet) shows a particular interest because obtaining the raw material is in a promising development showing good results for its industrial scale implementation. In order to evaluate this technology, its study is proposed through the modeling and simulation of the process. The ATJ process consists of four main stages, dehydration, oligomerization, hydrogenation, and separation. These processes are modeled in the Aspen plus software, in order to obtain the necessary mass and energy balances to evaluate the process performance and calculate the proposed objective functions. In order to design the process, a DETL optimization algorithm is used, which is programmed in Visual Basic and linked to the simulation software. To guarantee an optimal design of the process, an economic function measured through the total annual cost (TAC) and an environmental function, calculated through the eco-indicator 99 (EI99) methodologies based on the life cycle analysis, is used. For the optimization of the process, the ethanol feed varied, the degrees of freedom of the process and the variation of the distribution of components in the reactor was considered to guarantee the properties that the bio-jet fuel produced should normally carry.
After the optimization process, the results show a trade-off between the proposed objectives, considering a utopian point in which it is considered that there is a balance between the objectives, the following information is generated: the optimum capacity of the plant is 445.12 kg/h of bio-jet fuel, with an optimal ethanol feed of 1239.67 kg/h, for these conditions the optimal TAC is 1.150x106 $/year with an environmental impact of 2.793x108 points/year, with a sale price of 1.876 $/kg of bio-jet fuel, the energy consumption of the process is 10.69 MJ/kg of jet fuel. This cost of sale would be reduced if the sale of the other generated components such as diesel is considered. Multi-objective optimization considering economic and environmental aspects of the transformation of alcohol and its subsequent upgrading to jet fuel proved to be an efficient tool for process evaluation.
