A research group from Ohio State, led by Liang-Shih Fan, has developed a new type of clean coal technology called Coal Direct Chemical Looping (CDCL) . The coal is reacted exothermically without combusting it with air. This process allows for careful control of pollutants and capture of 99% of CO2 emissions .
CDCL Cycle Overview 
Chemical Reaction 
The pulverized coal is “directly” oxidized using heat and small beads of iron oxide in a sealed chamber where exhaust gases are easily captured . Then, air is introduced to the spent iron beads in a separate chamber, re-oxidizing them and preparing them for reuse (the “looping”) . This pair of reactions generates large amounts of heat which feeds the coal reaction and could also be used to generate steam for a traditional turbine cycle .
An experimental plant, illustrated below, was operated for over 200 consecutive hours in Fan’s lab, ultimately generating 25 kW of useful thermal output . Based on the team’s success, the Department of Energy has issued a million-dollar grant for a large scale trial plant to be built in Ohio . It will produce 250 kW of thermal output using a similar process tuned for syngas instead of pulverized coal .
Experimental CDCL Reactor 
Simulations that the team ran in ASPEN plant modeling software indicated that a full scale plant would be 33% more expensive to operate based on $/MWh than a regular plant, but would capture 97% of the CO2 emissions . For comparison, a plant with similar sequestration abilities using the current technology of monoethanolamine [MEA] stack scrubbing would capture 90% of emitted CO2 but would cost 71% more than a basic plant , .
Model Plant Economics 
Model Plant Performance 
The research performed by Fan’s group has produced a clean coal technology that would allow us to use our nation’s abundant coal resources while producing significantly fewer emissions at the smokestack — and at a price point that is significantly better than competing clean coal technologies.