October 15, 2008

Bringing down the cost of SO2 and NOx removal

Stephen M. Kohan, PhD, Terry W. Rettig, and T. Steven Torbov, APTECH CST, LLC and Thomas K. Gale, PhD, Southern Research Institute

The future is bright

APTECH CST has received a contract for a preliminary engineering study leading to a full installation of its technology for SO₂, NO_x, and mercury control at a utility power plant. This installation should be operational by the summer of 2009. After APTECH CST’s technology is installed at the plant, the existing wet scrubber will be eliminated, storage ponds will be removed from service, and there will be no further discharge of treated wastewater to a nearby river.

APTECH CST is also developing a testing and engineering protocol for new projects. This involves a combination of computational fluid dynamics and cold-flow testing to optimize the location and characteristics of the slurry injectors.

APTECH CST also plans to optimize the various ratios (such as Ca/S for SO_x and NSR for NO_x) by fully employing pilot-scale testing at Southern Research Institute. Because every coal has different combustion properties, Southern Research Institute can effectively simulate the burning temperature/time profiles for commercial boilers in its pilot plant. A number of state-of-the-art instrumentation technologies will be used, including the Infra-View Wireless Boiler Thermometer (www.jnt-tech-serv.com), a passive infrared detector based on the CO₂ absorption spectrum suitable for external installation on boilers, to measure flue gas temperatures inside operating boilers and pilot plants.

Once optimized ratios have been established, the company will proceed with engineering of the complete installation. APTECH CST has received a contract for the engineering phase and a portion of the simulation phase for another power plant to control SO₂ and NO_x emissions to meet both current and future federal and state requirements.

—Stephen M. Kohan, PhD (skohan@aptecheng.com) is manager of corporate technology; Terry W. Rettig, PE (trettig@aptecheng.com) is CEO; and T. Steven Torbov (storbov@aptecheng.com) is principal combustion specialist for APTECH CST, LLC. Thomas K. Gale, PhD (gale@southernresearch.org) is director of power system research at Southern Research Institute.