Innovative concepts for hydrogen production processes based on coal gasification with CO2CO2 capture

This paper investigates the technical aspects of innovative hydrogen production concepts based on coal gasification with CO2CO2 capture. More specifically, it focuses on the technical evaluation and the assessment of performance of a number of plant configurations based on standard entrained-flow gasification processes (dry feed and slurry feed types) producing hydrogen at pipeline pressure, which incorporate improvements for increasing hydrogen purity and pressure. The dry feed type of entrained-flow gasifier is currently considered to be the most efficient means of producing hydrogen from coal. The main shortcomings are relatively low hydrogen purity due to the need of using nitrogen as a transport gas for the coal and a pressure limitation of this type of design. The purity issue can be solved by using captured CO2CO2 to transport the coal in the gasifier. The pressure limitation can be overcome by using in-plant compression of the raw syngas. Simulations, made using commercial process flow modelling packages (ChemCAD), show that these changes can be made without compromising plant efficiency; on the contrary, the efficiency slightly increases because of the better thermal integration of the plant.