Continuous Process for the Production of Aromatic Hydrocarbons from n-Hexane and C5+ Natural Gas Liquid over Pd-Loaded ZSM-5 Zeolite

A continuous process for the production of aromatic hydrocarbons from n-hexane and C5+ natural gas liquid (C5+ NGL) over Pd-loaded ZSM-5 zeolite in a tubular reactor was developed. The optimal conditions for continuous aromatization of n-hexane and C5+ NGL were found at 400 °C reaction temperature and 0.4 cm3/min reactant feeding rate, employing ZSM-5 (0.5% Pd content) as a catalyst; under these conditions, n-hexane conversion and aromatic contents in reaction product were found to be 99.7% and 92.3%, respectively. GC and GC/MS analysis revealed that this continuous process for n-hexane aromatization yielded both benzene derivatives and naphthalene derivatives, including benzene (5.7%), toluene (23.6%), xylenes (25.0%), 4-ethyltoluene (3.5%), 1,3,5-trimethylbenzene (4.9%), 1-methylnaphthalene (4.3%), and 1,5-dimethylnaphthalene (3.6%). Under the same reaction conditions, C5+ NGL gave 94.3% conversion and 92.6% aromatic contents in reaction product. The composition of product included benzene (8.1%), toluene (23.3%), xylenes (22.8%), 4-ethyltoluene (4.3%), 1,3,5-trimethylbenzene (3.7%), 1-methylnaphthalene (4.1%), and 1,5-dimethylnaphthalene (2.9%).