Process Intensification Applied to Biojet Production Through ATJ Process

With the increase in global energy consumption, concern for the environment and material resources, it is imperative that the industry seeks continuous improvement of processes. The aviation sector influences this issue by the growing need for its use impacting the global economy. During 2017, more than 4.1 billion passengers and 539 million metric tons were transported, which represents about 35% of global trade by value. Besides, the number of passengers is expected to double by 2036, increasing jet fuel consumption, hence the need to implement a viable alternative to replace them in a sustainable way and with a sustainable process. There are some routes for the production of bio jet fuel, for example, hydro processing of fatty acids and esters (HEFA), (Wang et al., 2020) however its application on an industrial scale is not entirely feasible due to the direct competition with arable land. On the other hand, it is possible to start from alcohols for the production of biojet fuel through the ATJ process (Alcohol-to-jet, ATJ) which was recently certified in April 2016 by ASTM. The ATJ process consists of 4 stages starting from ethanol, (i) dehydration, (ii) oligomerization, (iii) hydrogenation, and (iv) purification. The ATJ route has bioethanol as a raw material, which has lignocellulosic agroindustrial waste as a precursor raw material that does not require additional water or long times to obtain it. However, one of the disadvantages is that it is a relatively expensive process and is still not sufficiently competitive in the market, compared to the conventional jetfuel production process. The process of obtaining biojet has been previously studied by several authors; however, it is a process with a wide field for improvement. Process intensification is a philosophy that attempts to generate better results, reducing the use of equipment, energy, resources, etc. In this sense, the use of PI strategies seems to be a promising alternative to generate a more competitive biojet production processes compared to the conventional biojet production process. The goal of this work was to design an intensified process to produce biojet fuel from Mexican lignocellulosic biomass having alcohols as intermediates. The process was modeled considering an intensified process for pretreatment/hydrolysis/fermentation/purification for the biomass-ethanol process. Also, a reactive distillation-based process for dehydration/oligomerization/hydrogenation/distillation was considered. Once designed, the entire process was optimized by employing the stochastic method of Differential Evolution with Tabu List to minimize the total annual cost and the ecoindicator-99 as objective functions to evaluate the sustainability of the process. The results show that savings of 20% in the total annual cost and a reduction of 18% in ecoindicator-99 in comparison with conventional production of biojet.