Abstract: Reactor configurations may include one or more staged inlets and/or one or more staged outlets for gaseous and solid feedstocks. In one embodiment of the present disclosure, a reactor design for gas-solid reaction with one or more additional outlet for gas and/or solid phase is provided. In yet another embodiment, the design for a gas-solid reactor with one side inlet and two outlets for gas phase is described. In one embodiment, a reactor design with pairs of inlet and outlet for both gas and solid phase is provided. In another embodiment, a reactor design with one or more side inlets but only one outlet for gas phase is provided. In yet another embodiment, a reactor design with two inlets at the top/bottom of reactor and two side outlets for gaseous phase is described. In yet another embodiment, a reactor design with one or more side inlets and outlets for both gas and solid phases is provided.