(696b) Oxygen Uncoupling Enhanced Iron Oxides for Solid Fuel Gasification – Oxygen Carrier Development, Reactive Testing, and Process Analyses

Oxygen Uncoupling Enhanced Iron
Oxides for Solid Fuel Gasification ? Oxygen Carrier Development, Reactive
Testing, and Process Analyses

Feng He, Nathan Galinsky, Yan Huang, Fanxing Li*

Department of Chemical and
Bimolecular Engineering

North Carolina State
University

Raleigh, NC 27695

* Email: fli5@ncsu.edu

Carbon
dioxide emitted from fossil energy conversion is estimated to account for ~ 20% of the greenhouse effect. In order to mitigate the
anthropogenic CO₂ emissions, effective carbon capture, utilization
and storage (CCUS) approaches need to be developed and adopted for fossil fuel
conversions. Chemical looping processes, which include chemical
looping combustion (CLC) and chemical looping gasification (CLG), utilize
novel, indirect strategy for fossil fuel conversion and CO₂ capture. The
CLC process is developed to produce heat/electricity. CLG, on the other hand, converts fuels into
separate streams of sequestrable CO₂,
hydrogen, and heat/electricity.

Although
Fe-based metal oxide is considered as the only suitable oxygen carrier for the CLG
process, the reaction between solid fuels such as coal and iron oxide tends to
be slow. In order to improve the reaction rate of the aforementioned reaction,
we propose to incorporate a secondary oxygen carrier such as CuO to the iron oxide based oxygen carrier for chemical
looping gasification of solid fuels.

To
validate the feasibility of this approach, oxygen carriers with varying
combinations of copper and iron oxides are synthesized. Reactions between the
oxygen carriers and coal/coal char are performed in both a Thermal-Gravimetric
Analyzer (TGA) and a bench-top fluidized bed reactor. Equilibrium based ASPEN
Plus® process simulation is also carried out to predict the reactor and process
performances.  The
simulation results indicate that copper oxide addition simplifies the process
heat integration scheme, and hence a high energy conversion efficiency for the
proposed bimetallic CLG concept can be expected. The potential environmental
impacts of the chemical loping process are also evaluated in the present study.