Potassium ash interactions with oxygen carriers steel converter slag and iron mill scale in Chemical-Looping Combustion of biomass – experimental evaluation using model compounds

Chemical-Looping Combustion (CLC) is a combustion technology in which a solid oxygen carrier is used to convert fuel. The oxygen carrier is oxidized in air and subsequently transferred to a separate reactor in which it reacts with the fuel. The produced CO2 is inherently separate from the air components, making CLC an promising technology for Carbon Capture and Storage (CCS). CLC of biomass combined with CCS (Bio-Energy CCS; BECCS) is a way to generate negative CO2-emissions and thus interesting for climate change mitigation. Undesirable chemical reactions between ash and oxygen carriers is a challenge in BECCS due to the reactive nature of biomass ash. This article examines two low-cost steel industry by-products that have shown desirable fuel conversion properties in CLC; iron mill scale (Glodskal B) and steel converter slag (LD-slag). Their interactions with potassium ash model compounds (KCl, K2CO3, K2SO4, and KH2PO4) in reducing atmosphere have been investigated. Mixtures of oxygen carrier and potass...