Gas switching technology: Economic attractiveness for chemical looping applications and scale up experience to 50 kWth

Abstract

Gas switching technology (GST) was introduced to facilitate operation and scale-up of pressurized chemical looping-based technologies thus bringing the expected benefits of reducing costs and energy penalty of CO2 capture. GST has so far been applied to generate heat/power, hydrogen, syngas, and oxygen using fossil fuel gas (but also from biomass for negative CO2 emissions) with integrated CO2 capture at minimal energy penalty generating over 50 publication studies demonstrating the technical feasibility of the technology and quantifying the potential energy and cost savings. In contrast to conventional chemical looping, GST inherently avoids solids circulation by alternating oxidizing and reducing conditions into a single fluidized bed reactor with an oxygen carrier, thus removing many of the technical challenges that hinder the scale-up of the technology. GST has successfully been applied and demonstrated for combustion, steam/dry methane reforming, and water splitting, using different oxygen carriers, showing the ease of operation under both atmospheric and pressurized conditions and achieving high products separation efficiency.This paper summarises the different studies completed on the Gas Switching Technology covering experimental demonstration (including the experience from a 50 kWth cluster), process modelling and techno-economics, highlighting the advantages and disadvantages of the technology and discussing the way forward.