Enriched methane production through a low temperature steam reforming reactor

Abstract

An innovative hybrid plant, composed by a solar section for heating up a molten salt stream through a Concentrating Solar Power (CSP) plant, a chemical section for the production of 1000 Nm3/h of Enriched Methane (EM) with a 20 %vol. content of hydrogen, and an electrical section for the electricity production by means of an Organic Rankine Cycle unit (conversion efficiency = 28 %) is presented and assessed. The core of the process is the low-temperature solar steam reformer, where a feedstock composed by methane and water steam is partially converted to hydrogen. The reactor is modeled in detail, the equations set is described and commented, together with the boundary conditions. Then, the reactors’ behavior is simulated. By applying 15 reformers in parallel and imposing a Gas Hourly Space Velocity (GHSV) of 40,965 h−1, it is possible to produce a stream of EM (20 %vol. H2 ) equal to 1000 Nm3/h and 500 kW approximately of net electrical power output. The molten salt stream is heated up to 550 °C by the CSP plant, then it supplies the reforming process heat duty (reactor heat duty, feedstock preheating, and reactant steam generation) and, finally, it generates the electricity by exploiting its residual sensible heat. By the simulation of the reformers under industrial conditions, the feasibility of the proposed architecture is demonstrated and its potentialities are assessed.