Evaluation of economic feasibility of hydrogen production by steam pyrolysis of natural gas in a thermal plasma reactor

Abstract

This study investigates the optimization of process parameters for hydrogen production via steam pyrolysis of natural gas in a thermal plasma reactor. A key advantage of plasma pyrolysis is its ability to achieve high hydrogen yields without producing carbon monoxide or carbon dioxide, as the main products of the process are solid carbon and hydrogen. Unlike conventional methods, plasma-based decomposition does not require catalysts, which is one of the major challenges in current technologies for hydrogen production from natural gas. The use of water vapor as a working medium in the thermal plasma process is expected to further increase the hydrogen yield. This research employs a thermodynamic equilibrium model based on the minimization of Gibbs free energy to analyze the process within a temperature range of 500–2500 K. The numerical analysis identifies an optimal process temperature of approximately 1200 K, at which methane conversion exceeds 95 mass percent. Additionally, the study evaluates the economics of the process by calculating the cost of hydrogen production, taking into account capital and operating costs, as well as projected profits. Considering capital costs, operating costs, and profit margins, the estimated hydrogen price is 3.93 €/kg. The sensitivity analysis shows that fluctuations in the price of the by-product solid carbon have the most significant impact on the hydrogen price, which ranges from 4.39 to 3.14 €/kg, depending on the price of solid carbon, which varies between 150 and 1100 €/t.