Study On Thermal And Catalytic Cracking Of Ethylcyclohexane

With the development of hypersonic vehicle technology, more and more attention has been paid on the study of the heat transfer performance of hydrocarbon fuels. This present work focuses on the study about basic physical properties, thermal cracking and the catalytic cracking reaction of model fuel ethylcyclohexane with lipophilic nano-particles. Detailed research could provide some experimental and theoretical basis on the heat transfer performance enhancement of hydrocarbon fuel. Important works and results are as followed:Comparing with the key properties such as density and net calorific value of the actual fuel, the model compound of ethylcyclohexane was screened out, and their basic properties were investigated. Densities, viscosities, surface tensions, and refractive indices for the ethylcyclohexane in the temperature range 293.15?343.15 K were measured, which can offer data information for the study on the compatibility of endothermic hydrocarbon fuel. Static thermal cracking reaction of ethylcyclohexane was investigated, which was analyzed by the First-order Kinetics, and the Arrhenius parameters were determined with the pre-exponential factor A=1.56×1014 h-1 and the activation energy Ea=209.40 kJ·mol-1.The mechanism of the thermal cracking reaction of ethylcyclohexane was discussed based on the analysis of pyrolysis conversion, gas yield and gas-liquid products.Lipophilic nanoparticles which the nano-metallic particles are wrapped with lipophilic surface modification agents, can be uniformly dispersed in the hydrocarbon fuels and other non polarity system. Those catalysts can interact with the fuel to form a nanofluid, which can catalyze the cracking of endothermic fuels under the "pseudo-homogeneous phase". Tetra-undecylcalix[4]resorcinarene, which is referred as C11-C[4]R, was prepared with resorcinol and dodecanal. Based on the referred calixarene, a sulfur-contained derivative was synthesized as C11-SC3. Four kind of lipophilic metal nanoparticles, Ni@ C11-SC3, Ni&Pd@ C11-SC3, Pd@ C11-SC3 and Pt@ C11-SC3 were obtained with the C11-SC3 as the coating agent. Dispersity, morphology, size distribution, metal content, elemental composition of the nanoparticles was characterized. In this study, the sizes of the obtained nanoparticles are all lower than 10 nm and exhibit excellent dispersion in model fuel ethylcyclohexane. The palladium and platinum nanoparticles are the smallest of all, whose average-size ranges from 2 to 4 nm.Static thermal cracking (constant volume pyrolysis) method was applied to study several catalytics'effect of lipophilic nanoparticles on the chemical reaction process of ethylcyclohexane, wherein the catalytic effect of Pt@ C11-SC3 best. Conversion rate, gas yield, gas-liquid product distribution of pyrolysis reaction was analyzed. The results show that lipophilic nanoparticles Pt@C11-SC3 can effectively improve the conversion rate of ethylcyclohexane, decrease the initial temperature of the reaction and promote the dehydrogenation reaction. Therefore, Pt@C11-SC3 is a suitable catalyst for the chemical reaction process of ethylcyclohexane. On these basises we explored the catalytic cracking mechanism of ethylcyclohexane. What's more, C11-SC3 was found to have a weak inhibition on the cracking reaction of ethylcyclohexane, but its use as the surface modification agent of nanoparticles was not affected.