A novel integrated Ca-Cu cycle with coal/biomass gasification unit for clean hydrogen production

Abstract

Energy is a vital and inseparable driver of the present industrial world. Nevertheless, the main concern, unlike in the past, is not only energy supply but also environmental issues must be considered. Hydrogen, an alternative energy carrier, is currently produced mainly from mature reforming technology, which leads to CO2 emission. Therefore, in this paper, a steam methane reforming unit is integrated with i) a Ca-Cu cycle, which is the combination of a CO2 capture cycle with CaO sorbent and a copper chemical combustion looping to meet the heat requirement, ii) a hydration step as well as iii) a gasification section for syngases generation. The novel proposed process is simulated in Aspen Plus software. Based on the results, the mass flow rate of produced H2 and captured CO2 are 4.68 kg/s and 51.85 kg/s, respectively. In terms of thermal load, the process requires 111 MW of external heat to bring the methane and steam mixture to 600 °C, and rest of the demand is often supplied by the cycle solely. The CO2 capture efficiency and thermal efficiency were obtained as 91.11% and 66.55%, respectively. Eventually, a sensitivity analysis was performed by selecting the decisive parameters, which include steam to carbon molar ratio, Ca(OH)2 to carbon molar ratio, temperature, pressure and steam to biomass and coal mass ratio.