The estimation of fugitive gas emissions from hydrogen production by natural gas steam reforming

Abstract

In recent years, a significant amount of interest has been directed towards using hydrogen as an alternative source of energy to fossil fuel. Even though hydrogen is emission free in its end use; the production of hydrogen itself requires energy and may cause process emissions including fugitive emissions from various sources, mainly the piping equipment and fittings. The emissions, even though not as large as stack emissions, they may still pose risks to the environment and health especially to the workers within the plant area. This paper presents the estimation of fugitive emissions from hydrogen production process via natural gas steam reforming. Firstly, the natural gas steam reforming process was simulated before the fugitive emissions of carbon monoxide (CO) and greenhouse gases (GHGs), such as methane (CH4) and carbon dioxide (CO2) in the process were estimated. Then, the consequent global warming potential (GWP) and the associated health risks due to the emissions were evaluated. A comparison of the GHG fugitive emissions with other sources of GHG emissions over the hydrogen production life cycle was also performed. Methane (CH4) recorded the highest rate of fugitive emissions contributing to the greatest GWP. On the other hand, CO2 represented the total stack emissions contributing to 100% of the total GWP. The concentrations of the gases emitted as fugitive emissions (CH4, CO2 and CO) in the process area are below the threshold exposure limit indicating that the plant environment is safe for workers daily exposures to the emitted gases.