Exploring novel hydrogen production processes by integration of steam methane reforming with chemical-looping combustion (CLC-SMR) and oxygen carrier aided combustion (OCAC-SMR)

This article discusses the concept of combining steam methane reforming (SMR) with fluidized beds of oxygen carrier particles and presents results from process simulations in Aspen Plus of new process outlines with and without carbon capture. Conventionally, heat to steam reforming tubes is provided by gas-fired burners, which transfer heat to the tube's surface mainly by radiation. An alternative approach to provide heat to the endothermic SMR reaction is to use fluidized bed technology, utilizing oxygen carrier particles as bed material. Two novel configurations of the steam reforming process are proposed. The first concept incorporates SMR with a single bubbling fluidized bed reactor of oxygen carrier particles, or Oxygen Carrier Aided Combustion (OCAC). The second combines Chemical Looping Combustion (CLC) with an external fluidized bed heat exchanger (FBHE) used for SMR. Here, biomass is used as supplementary fuel in the furnace. The results for the OCAC-based system show that the cold gas efficiency can be increased compared to a reference case describing a conventional process, and at the same time decrease CO2 emissions by 4%. The biomass-fuelled CLC configuration displays surprisingly large negative CO2 emissions, corresponding to a CO2 emission reduction by 151% compared to the reference case.