Energy, environment, and economic analyses on a novel hydrogen production method by electrified steam methane reforming with renewable energy accommodation

Abstract

More and more attention has been paid to hydrogen due to its cleanity and high energy density. However, hydrogen production from conventional steam methane reforming has high CO2 emission and heat loss in the flue gas. Hydrogen from water electrolysis has the defects of high cost and low efficiency. Electrified steam methane reforming (E-SMR) process is proposed by integrating power to gas technology with steam methane reforming based on the principle of efficient electrothermal conversion and energy cascade utilization. Electrical equipment is used in the process to eliminate the above drawbacks and accommodate renewable electricity. The novel process is simulated by chemical equilibrium and mass-energy conservation methods and analyzed from energy, environment, and economy. The optimal performance of E-SMR processes is investigated by adjusting the steam carbon ratio and reforming temperature under appropriate pressure. The optimal thermal efficiency (97.27 %) is improved by 18 percentage points at least compared to current industrial steam methane reforming processes. The optimal electrical efficiency (88.68 %) is at least 11.48 percentage points higher than that of running commercial water electrolysis systems. The novel process achieves low carbon emission (even zero-emission with CCS) since the required reforming energy is electricity instead of combustion. The cost of the proposed process can be minimized to 2.47 $/kg H2 through economic analysis. This work may provide an efficient, low-carbon, and economical option for hydrogen production.