Hydrogen sulfide methane reforming: A kinetic modeling and techno-economic analysis study

Abstract

Hydrogen sulfide (H2S) methane (CH4) reforming (H2SMR) is a promising process for sustainable energy production from conventional fuels, offering triple benefits for generating clean hydrogen (H2), consuming toxic H2S, and producing an economically valuable by-product carbon disulfide (CS2). In this work, we studied the optimal operating conditions and assessed the economic feasibility of the non-catalytic H2SMR process, employing a combination of kinetic modeling, process modeling, and techno-economic analysis. Plug flow reactor simulations were performed with our newly developed mechanism to shed light on the optimal operating conditions. It was concluded that a H2S/CH4 molar feed ratio of 2 results in the highest hydrogen production rate, and a feed ratio of 1–2 and a temperature of 1100–1300 °C are needed to maximize the CS2 production rate. However, feed ratios higher than 2 increase the conversion rate of CH4 and therefore benefit the purity of the H2 product. Comparing the cases for a feed ratio of 2 at 1300 °C and a feed ratio of 9 at 1200 °C, the cost is significantly higher for the feed ratio of 9, mainly attributed to the higher electricity cost for higher inlet flow rate and H2S recycling, as well as the cost for the additional steam required during the preheating process. The cost of hydrogen production by H2SMR process could be as low as $1.47/kgH2 for a feed ratio of 2 and solar PV as an energy source, which is more competitive than a cost of $1.97/kgH2 for the steam methane reforming process. Furthermore, since CS2 is a valuable by-product, the higher amount of CS2 formed at a feed ratio of 2 becomes the main source of revenue, which completely covers the cost of hydrogen production. This study demonstrates the huge potential of H2SMR process as a clean and economic-competitive way to produce hydrogen.