The report gives results of a technical/economic assessment of Exxon's Thermal DeNOx Process, applied to coal-fired utility boilers. The assessment was performed in parallel with a study in which the performance/cost of the process was estimated for eight coal-fired utility boilers representative of the Nation's boiler population. The report concludes that the process is a promising technique for controlling NOx emissions from utility steam generators. However, a number of limitations need to be evaluated when the process is retrofitted to coal-fired boilers. Flue gas temperature fluctuations (caused primarily by load following, furnace slag deposition, and tube fouling) may limit NOx reductions to approximately 50%. In addition, operational and environmental impacts of NH3 emissions and ammonium bisulfate formation could further limit the performance of the process and affect its applicability. These limitations are best evaluated on full scale. Total operating costs are estimated between 0.27 and 1.23 mills/kWhr, exclusive of license fee. Actual costs depend primarily on boiler size, initial NOx concentration, and level of control required. The assessment also considered the impact of widespread process implementation on the ammonia market, feedstock supplies, and their costs. The impacts were found to be small.

Project Officer: David G. Lachapelle. Acurex Corp., Energy and Environmental Division "May 1979." Includes bibliographical references. "EPA-600/7-79-117."