Novel carbon-neutral hydrogen production process of steam methane reforming integrated with desalination wastewater-based CO2 utilization

Abstract

Steam methane reforming (SMR) process is facing serious greenhouse effect problems because of the significant CO2 emissions. To reduce pollution caused by gaseous emissions, desalination wastewater can be used because it contains highly concentrated useful mineral ions such as Ca2+, Mg2+, and Na+, which react with carbonate ions. This study proposes a novel SMR process for carbon-neutral hydrogen production integrated with desalination wastewater-based CO2 utilization. A process model for the design of a novel SMR process is proposed; it comprises the following steps: (1) SMR process for hydrogen production; and (2) desalination wastewater recovery for CO2 utilization. In the process model, the CO2 from the SMR process was captured using the Na+ ion, and the captured ionic CO2 was carbonated using the Ca2+ and Mg2+ ions in desalination wastewater. The levelized cost of hydrogen (LCOH) was assessed to demonstrate the economic feasibility of the proposed process. Therefore, 94.5 % of the CO2 from the SMR process was captured, and the conversion of MgCO3 and CaCO3 was determined to be 60 % and 99 %, respectively. In addition, the CO2 emission via the proposed process was determined to be 0.016 kgCO2/kgH2, and the LCOH was calculated to be 2.6 USD/kgH2.