Optimization for sustainable hydrogen production path

Abstract

Hydrogen, a clean multipurpose energy carrier with application in various industrial and chemical processes has been identified as a key player in meeting the global clean energy sources target. There are several ways to produce hydrogen, however, 95% commercial hydrogen is produced via steam methane reforming (SMR) which emits CO 2 as byproduct making it environmentally unfriendly. Although carbon capture sequestration (CCS) can be applied, only about 90% CO 2 capture has been reported in the literature, and the burgeoning water electrolysis technology which enables zero GHG emission depending on the source of energy applied is quite expensive and limited. Hence the increasing research attention on Methane pyrolysis (MP). In this study, the different TDM technologies are explored to develop an optimization model that considers energy efficiency, CO 2 emission and water consumption in production of hydrogen at a minimum cost, selecting a sustainable MP path that is comparable to prevalent technologies– SMR with and without CCS as well as water electrolysis- for further research. An MINLP optimization model for selecting a sustainable pathway to produce hydrogen in commercial quantity is formulated using associated data from the literature with respect to the different technologies considered. Sensitivity analysis is also performed to analyze the impact of the by-products produced from each technology on the cost of production. The model is implemented in GAMS. The findings from this work selected TDM with Plasma and TDM with metal catalyst as the optimal hydrogen production pathways that can compete with prevailing technology for sustainable hydrogen production based on the process performance index considered. It also shows that the quality of carbon could greatly influence the commercialization of MP. Moreover, MP is flexible and can attain carbon-neutrality depending on the feedstock and energy source. However, the results show that this transition depends on the cost and availability of renewable energy sources. With the supposition that MP Low to zero CO 2 emission and valuable solid carbon product features makes it sustainable, TDM technology should be explored to compete with the current technology to meet hydrogen demand, and this study provides a pointer to the optimal TDM technology as well as precedes a process simulation that explores the kinetics and thermodynamics for optimization.