Internally circulating fluidized-bed reactor for syngas production using chemical looping reforming

Abstract

Chemical looping reforming (CLR) is a promising method for achieving autothermal methane reforming without the energy penalty of an air separation unit that is required for partial oxidation (POX) or oxygen-blown autothermal reforming (ATR). Scale-up of the conventional dual circulating fluidized bed CLR configuration is challenging, however, especially under the pressurized operating conditions required for high process efficiency. The internally circulating reactor (ICR) concept has previously been proposed as a simplified solution for chemical looping, especially under pressurized operation. It assembles the chemical looping process into a single reactor with two sections connected by specially designed ports for oxygen carrier circulation. This study has successfully demonstrated CLR operation in a dedicated ICR test unit with a NiO oxygen carrier. Up to 3 kW of methane feed was reformed to syngas, achieving conversion efficiencies as high as 98%. The reactor behaved largely as expected over a range of CH4/O2 ratios and in a case with steam addition. Autothermal reactor operation could also be achieved, illustrating the practicality of the ICR concept. Based on this positive first demonstration study, further study of the ICR concept is recommended.