Chemical looping combustion for solid fuels: in situ gasification chemical looping combustion and chemical looping with oxygen uncoupling

In situ gasification chemical looping combustion and chemical looping with oxygen uncoupling are the two main strategies used for the implementation of direct solid fuels chemical looping combustion. Whatever the strategy, the use of solid fuels poses several challenges to be addressed. Among these there is certainly the need to use appropriate oxygen carriers that can work without reporting negative changes to their chemical and mechanical properties, such as possible interaction with ashes. A second challenge is to minimize the bypass of volatiles that leads to losses in terms of conversion performance by adopting innovative plant solutions. Another challenge concerning ash is that of operating an efficient separation from the oxygen carrier to avoid carrier losses in the drainage flow. A final challenge is the possibility of efficiently separating the solid char from the oxygen carrier entering the air reactor to increase the overall performance of the process.