Ammonia Decomposition Over Cobalt-Based Silica-Supported Fischer-Tropsch Synthesis Catalysts

Abstract

Decomposition of ammonia over silica-supported cobalt catalysts for Fischer–Tropsch synthesis has been studied at a pressure of 0.1 MPa, a gas hourly space velocity range of 1000–6000 h–1 and a temperature range of 400–650°C in a tubular fixed bed reactor in a flow-through mode. It was found that silica-supported cobalt catalysts for hydrocarbons synthesis via the Fischer–Tropsch protocol also exhibit high activity in ammonia decomposition. Both activity and hydrogen productivity decrease in the series: Co–Ru/SiO2  Co–Al2O3/SiO2 Ru/SiO2 Co–Al2O3/SiO2(35%)/ZSM-5(30%)/Al2O3(35%). The relatively low values of effective activation energies estimated for all catalysts indicate that the reaction can proceed with a high conversion at moderate temperatures.