Effect of the Light Alkane Content of Natural Gas on the Production of Hydrogen and Coke During the Dry Reform

Solange Maria de Vasconcelos,

Abstract

Dry reforming of ethane and propane were carried out with a nickel catalyst (3.92% by weight/γ-Al2O3) to characterize the effects of fed light alkanes on the reforming process of natural gas. Conversions of individual alkanes, representing 74.7% for ethane and 96.0% for propane at 1073 K, promoted hydrogen yields of 43.6% and 66.0%, respectively. The conversion (81%) of a natural gas promoted a 95% hydrogen yield, where about 20% had been obtained from the light alkanes. The reaction steps from alkane dry reforming where hydrogen was produced (alkane cracking) provided carbon formation with a yield of 23%. A kinetics evaluation, based on experimental evidence that indicated two different sets of reaction steps for both ethane and propane processes, enabled the identification of the specific reaction rates of the cracking steps for each alkane.  Reaction steps in the reforming process were considered as competitive reactions and the specific cracking reaction rates of both light alkanes were used to quantify the kinetic selectivities of hydrogen, calculated as 95.42% for ethane and 76.99% for propane.