Experimental evaluation of interactions between K, Ca, and P and Mn/Si-based oxygen carriers

Paper i proceeding, 2017

Oxygen carriers are solid metal oxides particles that are able to provide and absorb oxygen via redox reactions. With oxygen carriers it is possible to provide oxygen in solid form for combustion or for fuel conversion. CO 2 -capture, hydrogen production, biogas gasification as well as combustion of waste, biomass or other fuels can be made more efficient and cheaper by the use of oxygen carries. This work experimentally examines the interaction between three elements commonly encountered in ashes from biofuel (K, Ca and P) with three oxygen carriers with different ratios of manganese and silica. In addition silica sand and pure manganese oxide particles were used as reference. The particles were mechanically mixed with salts from either K, Ca or P and placed in a furnace at 850°C with either a reducing or oxidizing atmosphere. This will for example mimic the intended use of these oxygen carriers as replacement of the bed material in FCB combustion (oxygen carrier aided combustion, OCAC) or in the use as oxygen carrier in a biofuel chemical-looping combustion (CLC) unit for CO 2 -capture. After exposure the interaction between particles and ash components where investigated with XRD and SEM. The result show that all oxygen carriers used here have less interaction with the selected ash components than in the equivalent case with silica sand. Out of the oxygen carries the one with a Si/Mn ratio of 10% performed best.