Title : Hydrodeoxygenation of aliphatic esters over sulfide Mo/Al2O3-zeolite catalysts
Abstract:
In the aviation industry, the use of hydrogen or electricity seems unlikely, therefore, jet fuel, the components of which are industrially obtained from esters or fatty acid triglycerides (FATs), in two stages, becomes the solution to the problem. First, a mixture of alkanes is obtained as a result of hydrodeoxygenation (HDO), then hydroisomerization/hydrocracking of alkanes is performed. The one-stage process of hydroprocessing of FATs into jet fuel components is more efficient; therefore, the development of polyfunctional catalysts that ensure the occurrence of several reactions simultaneously (HDO, hydroisomerization, and hydrocracking) is a promising area of research that has been actively developing in recent years.
For this purpose we carried out experiments to study peculiarities of aliphatic esters or fatty acid triglycerides’ (TG) conversion in the presence of catalytic system containing MoS2 nanoparticles on composite supports which includes zeolite materials that are active in isomerization reactions (silicoaluminophosphate SAPO-11, zeolites-ZSM-12, ZSM-5). Molybdenum sulfide provides high selectivity for the conversion of aliphatic esters and TGs via the direct “HDO” route without the formation of carbon oxides.
The catalysts were synthesized by impregnation of the supports with an aqua solution prepared by dissolving MoO3, H3PO4, and diethylene glycol in distilled water, followed by drying at 110°C for 4 hours. A comparative study of the prepared catalysts in the reactions of methyl palmitate (MP) conversion in a flow reactor at temperatures of 230–350°C (with an interval of 20°C), a hydrogen pressure of 3.0 and 5.0 MPa, a hydrogen/feedstock ratio of 600, and an LHSV of 36 h-1 showed that the introduction of zeolites leads to an increase in MP conversion by 10–15% in all temperature range. 100% conversion of oxygen-containing compounds is achieved at a temperature of 310°?, while the proportion of products of C15 and C16 iso-alkanes increases with increasing reaction temperature. A comparative study of sulfide Mo catalysts was performed, differing in the amount of additives in the composition of the composite support, in hydroisomerization, hydrocracking and hydrodeoxygenation (HDO) of aliphatic esters (differing in the length of the carbon chain and the number of double bonds) and fatty acid triglyceride.
Audience Takeaway:
- Our work may help the audience who work in the same field to design a better bifunctional catalyst in the reactions of hydrodeoxygenation/hydroisomerization simultaneously.
- The preparation and the characterization of sulfide catalysts supported on composite materials as well as the description of catalyst properties related to the result of aliphatic
