The report gives results of an evaluation of the effectiveness of combustion-type fuel oil additives to reduce emissions and increase efficiency in a 50-bhp (500 kw) commercial oil-fired packaged boiler. Most additive evaluation runs were made during continuous firing, constant-load operation of the boiler. Additives, both proprietary and pure compounds, containing alkaline-earth and transition metals in concentrations between 20 and 50 ppm were effective in reducing carbon particulate emissions by as much as 100 percent when firing residual oil. They also were effective in reducing emissions of smoke and polycyclic organic matter. No additive was found to be effective in reducing either NOx or SOx. Certain of these additives used in residual oil permitted an increase in overall boiler efficiency by reducing stack gas loss, without increasing particulate emissions. This efficiency gain, about 2%, was achieved by: appropriate readjustment to permit boiler operation at lower excess air levels; and reducing the fouling of boiler heat-transfer surfaces. Both proprietary and pure compounds were found to be equally effective. Thus, if additives are used, cost savings can be maximized by using the less expensive pure compounds.

Prepared by Battelle-Columbus Laboratories, Columbus, Ohio, under contract no. 68-02-0262, ROAP no. 21ADG-020, program element no. 1AB014, for U.S. Environmental Protection Agency, Office of Research and Development, and U.S. Federal Energy Administration, Office of Energy Conservation and Environment. Includes appendixes. Includes bibliographical references (pages 106-113).