180 MW demonstration of advanced tangentially-fired combustion techniques for the reduction of nitrogen oxide (NO{sub x}) emissions from coal-fired boilers. Technical progress report second quarter, 1991, report, December 31, 1991; (https://digital.library.unt.edu/ark:/67531/metadc1275170/m1/1/: accessed July 16, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .