Effect of zeolite 3.7 ̊ A coated monoliths on improvement of aviation fuel thermal oxidative stability

The effect of zeolite 3.7 ̊ A acidity on the reduction of surface deposition propensity of a Jet A-1 fuel, with marginal thermal oxidative stability was studied. This was achieved through treatment of the fuel in a packed bed reactor, using three types of monolithic zeolite with different Si/Al ratios. It was found that the increase of acidity is directly proportional to the surface deposition reduction such that the treatment with the highest ratio (Si/Al = 25) resulted in the most significant surface propensity reduction. However, a combination of zeolite with the lowest acidity (Si/Al = 17) and the activated carbon exhibited the greatest improvement of thermal oxidative stability. As a general trend, for all three Si/Al ratios in the monolithic zeolites used in this work, surface deposition propensity of the Jet A-1 fuel decreased markedly with the increase of monolithic size. Nevertheless, it is anticipated that efficacy will reach an steady state after a certain point. Quantum chemistry calculations demonstrate that polar species can interact with the CHA and 2Al doped chabazite in a number of ways, from dispersion interactions to forming covalent and hydrogen bonds. Furthermore, our calculations suggest that the doping CHA with Al enhanced the adsorption of polar species, which agree with a lab-scale experiment with the model fuel.