Characterization of Navajo Generating Station emissions measured during the June–July 1979 vistta field program

Abstract

The Salt River Project, joint owner and operating agent for the Navajo Generating Station, participated in the jointly sponsored EPA-SRP June–July 1979 VISTTA Field Study. As part of this broad and intensive study, Salt River Project conducted an emissions measurements program at this power plant. This paper presents a brief description of the measurement techniques used and a summary of results. The program included measurements for paniculate and gaseous, sulfur dioxide and oxides of nitrogen, emissions and the determination of particle size distributions. The particulate and gaseous measurements were conducted in accordance with EPA Reference Methods 1–7. Particle size distributions were determined by a combination of techniques. Cascade impactors were used to collect data in the coarse panicle size range, 0.15 to 10 μm. Data in the fine particle range, 0.4–2.0 μm, and ultrafine particle range, 0.01–0.3 μm, were acquired by optical particle counter and electrical aerosol analyzer techniques, respectively. Size segregated particulate samples, 0.4–5.0 μm, were collected by a five stage series cyclone for subsequent chemical analysis. The elemental compositions of the cyclone samples were determined by neutron activation and wave length dispersive X-ray fluorescence. Station operating status (unit load, coal burn rate, etc.), precipitator performance and equipment problems were monitored and recorded. Coal samples were collected and analyzed for chemical compositions. The particle size distribution results indicated that the Unit 3 stack emissions were bimodal and that each distribution could be considered to be log normal. The stack measurements showed that there were significant variations in paniculate mass emissions between tests and between units. The SO 2 and NO x results were typical of emissions expected for normal operating conditions. Thirty-one elements were found in the cyclone samples by the elemental analyses.