A new coal combustion power technology being advanced at Washington University in St. Louis offers the potential to deliver reliable low-carbon power at a reduced cost. The process is based on oxy-combustion technology which removes most of the nitrogen contained in air prior to combustion, burning fuel in a near-pure oxygen stream instead of air.

The researchers received a $6.7 million grant from the U.S. Department of Energy to continue developing the staged pressurized oxy-combustion (SPOC) process. Together with project partners from West Virginia University, University of Utah, the Electric Power Research Institute, Doosan Babcock, Linde, Reaction Engineering International and AECOM, the team will design a system to supply power as needed with minimal emissions.

First-generation atmospheric oxy-combustion technology relies on a flue gas recycle (FGR) diluent to reduce the peak temperatures achieved and the resulting high thermal radiation levels that would otherwise occur in a fuel/oxygen only flame. In contrast, by staging the combustion in several steps, SPOC reduces the peak temperatures of combustion without resorting to a high degree of FGR to control flame temperatures. The SPOC process operates by utilizing two or more pressurized boiler modules connected in series to produce fuel staging; only a portion of the fuel is combusted in any given combustion module. Subsequently the thermal energy released at each stage can be captured and removed from the gases prior to subsequent stages, when more fuel is introduced.

SPOC can increase process efficiency up to 6% over conventional oxy-combustion, and when combined with carbon capture the efficiency of this approach exceeds that of the average U.S. coal fleet.

A $6.7 million grant from the U.S. Department of Energy twill fund continue development of SPOC technology. Source: U.S. Department of Energy