Impact of oxy-fuel combustion on ash properties and sintering strength development

For a successful implementation of the oxy-fuel combustion technology, a good understanding of ash-related issues has to be achieved. Knowledge is still lacking on how oxy-fuel combustion can affect ash properties and its sintering behavior. These are the focus of the present work. Combustion experiments of a sub-bituminous coal were carried out in a drop tube furnace at 1573 K and under air and different oxy-fuel conditions (i.e.OXY21: 21 vol%O2/79 vol%CO2, OXY27: 27 vol%O2/73 vol%CO2 and OXY32: 32 vol%O2/68 vol%CO2). The bulk ash samples were collected and subjected to analyses by techniques such as computer-controlled scanning electron microscopy (CCSEM), X-Ray Diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Sintering tests of the bulk ashes were performed at temperatures ranging from 1023 to 1223 K. The compressive strength of sintered ash was characterized. The results show that oxy-fuel combustion has significant impacts on ash speciation rathe...