Metal impregnation on steel converter slag as an oxygen carrier

Abstract

Oxygen carriers used in chemical looping processes operated with biofuel are affected by the inorganic matter of the fuel. It is therefore expected that the lifetime of the oxygen carrier is limited, and preferably low-cost oxygen carriers should be used. Oxygen carriers based on iron ore or steel manufacturing waste products are available in significant quantities at low cost. However, it is common for these types of materials that their reactivity is low. This study investigates the effect of adding small amounts of more reactive elements into steel converter slag, also called LD slag.

Slag particles were wet impregnated with 2 or 5 wt.% of Ni, Cu, Mn, or Ce. The new material's morphology was evaluated using X-Ray Diffraction and SEM-EDS. Changes in reactivity towards CO, CH₄ and the model tar molecule benzene were evaluated using a bench-scale laboratory fluidized bed reactor.

It was observed that even small amounts of either Ni, Cu, or Mn could increase reactivity toward CO. Both Cu and Mn formed phases with LD slag that released oxygen via CLOU (chemical looping with oxygen uncoupling) and increased the conversion of methane and benzene. Ni and Ce doping also increased methane conversion but had only a minor effect on the benzene conversion. © 2023 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.