Effect of coexistence of siloxane on production of hydrogen and nanocarbon by methane decomposition using Fe catalyst

Abstract

Biogas derived from sewage sludge contains CO2, siloxane, and methane. In this study, the effect of coexistence of siloxane on the production of hydrogen and carbon nanofiber by methane decomposition using iron oxide-alumina catalyst was investigated. The catalyst was reduced by heating in a flow of methane. Siloxane addition to methane caused a catalytic activity at lower temperatures, shortened the induction period prior to the activity, and accelerated catalytic deactivation. Thermal decomposition of siloxane can occur at a lower temperature compared to that of methane. Carbon species formed by the siloxane decomposition may have a higher reducibility than methane does. The reactivity may lead to a carbon deposition at a lower temperature. Coexistence of CO2 and siloxane can prolong a catalytic lifetime because CO2 may inhibit the carbon deposition on catalyst to some extent.