News | June 2, 1999

Gas Reburn Systems Reduce NOx Emissions From Coal-Fired Electricity Generation Boilers

Even as they meet the heavy seasonal cooling demand, four mid-Atlantic electric utilities anticipate a drastic reduction in emissions from their power plants this summer. Baltimore Gas and Electric (Baltimore), Duquesne Light Co. (Pittsburgh), Public Service Electric and Gas (Newark, NJ), and Conectiv (Wilmington, DE) will all use newly installed natural gas reburn systems to reduce emissions of nitrogen oxides (NOx) from their coal-fired electric generation boilers.

The technologies, developed and licensed by Gas Research Institute (GRI; Chicago), inject 5–25% of the total energy input as natural gas above the furnace's main combustion zone to reduce NOx by about 30–65%. Before reburn technologies were commercialized, they underwent extensive field testing by GRI contractors to confirm NOx-reduction benefits and application requirements for various boiler types.

"We now have a portfolio of gas reburn technologies to provide utilities with a range of economical choices for complying with regulations that require different NOx reductions for the more than 1,000 existing coal-fired boilers," said John Pratapas, GRI principal product manager. "The three versions of reburn coming on line this ozone season can provide a 30–65% NOx reduction, at costs of about $700 to $2,000 per ton of NOx removed."

The three natural gas reburn systems available are:

  • Conventional Gas Reburn (GR). Baltimore Gas and Electric installed two GR systems at its Crane Station near Baltimore. The units were supplied by EER Inc. (Orrville, OH). A GR unit is also being installed by EER at Conectiv's Edge Moor #4, a 160-MW tangentially fired boiler in Wilmington, DE.
  • Fuel Lean Gas Reburn (FLGR). Duquesne Light installed FLGR units on three 100-MW roof-fired coal boilers at its Elrama Station near Pittsburgh. The units, supplied by ESA Environmental Solutions LLC (Pittsburgh), are designed to provide 30–35% NOx reduction at a gas usage of about 5% of total heat input.
  • Amine-Enhanced Fuel Lean Gas Reburn (AE-FLGR). The first commercial installation of an AE-FLGR unit began on May 1 at Public Service Electric and Gas's Mercer station near Trenton, NJ. The technology, supplied by Fuel Tech Inc. (Naperville, IL) on two 320-MW wet-bottom, wall-fired units, has a NOx-reduction guarantee of 60%.

GRI, established in 1976, manages cooperative R&D programs for its 329 members and the natural gas industry.

For more information, call John Pratapas of GRI at 773-399-8301, or e-mailjpratapa@gri.org.