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Sulfuric Acid and Nitrate Emissions from Oxidation Catalysts
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1975 by SAE International in United States
Annotation ability available
The authors have investigated the emission of sulfuric acid and nitrates from a 1973 Ford 351C V-8 engine equipped with prototype 1975 emission controls and mounted on a dynamometer test stand. Tests were performed on unleaded fuel at 60 mph road-load conditions, using monolithic noble-metal catalysts and no catalyst, and at 60 and 30 mph road-load conditions using a pellet-bed noble-metal catalyst.
Sampling for SO2 and H2SO4/SO3 measurement was effected at several points within the exhaust system as well as from a dilution tunnel where the exhaust was diluted ten-fold with filtered air. Samples collected in the dilution tunnel were analyzed for total particulate mass, sulfate, condensed water, and pH. Ammonia injection into the dilution tunnel on selected runs permitted collection of nitrate and HNO3 on the filters as NH4NO3.
Nearly all of the fuel sulfur was emitted as SO2, and less than 1% as sulfate, in the absence of a catalyst. With the catalyst, about 43% of the emitted sulfur was in the form of sulfate at 60 mph (monolith or pellet), and 86% at 30 mph (pellet catalyst). Sulfate storage in the monolithic catalyst at 60 mph road load was negligible. Some sulfate storage was noted in the pellet-bed catalyst at 60 mph road load. Afterwards, substantial storage occurred in the pellets at 30 mph; the storage rate was >50% of the sulfur consumed during the first 2 h of 30 mph operation; with further cumulative storage the storage rate declined to ∼15% of the consumption rate after 1000 miles at 30 mph, at which time the pellets contained 3% sulfate. Catalyst-produced particulate emissions were composed almost entirely of sulfuric acid and associated water. About 95% of the H2SO4 mass (with catalyst) was composed of droplets of less than 0.3 μm aerodynamic diameter. The amount of nitrate present in the engine exhaust was very low (≲300 μg/mi), and was not perceptibly enhanced by the presence of a catalyst.
CitationTrayser, D., Blosser, E., Creswick, F., and Pierson, W., "Sulfuric Acid and Nitrate Emissions from Oxidation Catalysts," SAE Technical Paper 750091, 1975, https://doi.org/10.4271/750091.
- Pierson W. R., Hammerle R. H., and Kummer J. T., “Sulfuric Acid Aerosol Emissions from Catalyst-Equipped Engines.” Paper 740287 presented at SAE Automotive Engineering Congress, Detroit, February 1974.
- Moran J. B., Manary O. J., Fay R. H., and Baldwin M. J., “Development of Particulate Emission Control Techniques for Spark-Ignition Engines.” EPA-OAP Publication APTD-0949 (NTIS PB 207312) (July, 1971).
- Gentel J. E., Manary O. J., and Valenta J. C., “Characterization of Particulates and Other Nonregulated Emissions From Mobile Sources and the Effect of Exhaust Emissions Control Devices on These Emissions.” EPA OAWP Publication APTD-1567 (March, 1973).
- Beltzer M., Campion R. J., and Petersen W. L., “Measurements of Automotive Exhaust Particulate Emissions.” Paper 740286 presented at SAE Automotive Engineering Congress, Detroit, February 1974.
- Begeman C. R., Jackson M. W., and Nebel G. J., “Sulfate Emissions From Catalyst-Equipped Automobiles.” Paper 741060 presented at SAE International Automobile Engineering Meeting, Toronto, October 1974.
- Bradow R. L., Carpenter D. A., Klosterman D., Black F. M., and Tejada S., “Sulfate Emissions From Catalyst and Non-CatalystNon-Catalyst Equipped Automobiles.” Paper 740528 presented at SAE Fleet Week, Chicago, June 1974.
- Hunter J. E., “Studies of Catalyst Degradation in Automotive Emission Control Systems.” Paper 720122 presented at SAE Automotive Engineering Congress, Detroit, February 1972.
- Stork E. O., “Oxidation Catalysts, the Clean Air Act, and the Energy Crisis.” Paper presented at the 167th National Meeting, American Chemical Society, Los Angeles, March 1974.
- Hammerle R. H. and Mikkor M., “Some Phenomena Which Control Sulfuric Acid Emissions From Automotive Catalysts.” Paper 750097 presented at SAE Automotive Engineering Congress, Detroit, February 1975.
- Melton C. W., Mitchell R. I., Trayser D. A., and Foster J. F., “Chemical and Physical Characterization of Automotive Exhaust Particulate Matter in the Atmosphere Second Year.” Battelle-Columbus Laboratories report to Coordinating Research Council, APRAC Project No. CAPE-19-70 (NTIS PB 221603), June 1973.
- Goksϕyr H., and Ross K., “The Determination of Sulfur Trioxide in Flue Gases.” J. Inst. Fuel, 35, (1962) 177-179.
- Fritz W. A., Jr., et al., ASME Performance Test Code PTC 19.10 (1968).
- Lisle E. S. and Sensenbaugh J. D., “The Determination of Sulfur Trioxide and Acid Dew Point in Flue Gases.” Combustion, 36, (1965) 12-16.
- “Method 8-Determination of Sulfuric Acid Mist and Sulfur Dioxide Emissions from Stationary Sources.” Federal Register, Vol. 36, No. 247, (December 23, 1971) pp. 24893-24895.
- Leithe W., “The Analysis of Air Pollutants.” Arbor Ann: Humphrey Science Publishers, 1970. Cited as references for this method: Kundig S.: Chem. Rundschau, 18, (1965) 123; Fielder R. S. and Morgan C. H.: Anal. Chim. Acta, 23 (1960) 538; cited in Z. Anal. Chem., 183, (1961) 455.
- Fritz J. S., and Yamamura S. S., “Rapid Microtitration of Sulfate.” Anal. Chem., 27, (1955) 1461-1464.
- “Standard Methods for the Examination of Water and Wastewater” (Distillation without digestion followed by titration: modified Kjeldahl), American Public Health Association, Washington, D.C., (1971) pp 224-225, 244-248.
- 1967 Annual Book of Standards, Part 23: Industrial Water; Atmospheric Analysis: American Society for Testing and Materials, Philadelphia (1972), ASTM Standard D992-71, “Standard Method of Test for Nitrate Ion in Water,”pp 124-126.
- 1972 Annual Book of Standards, Part 23: Water; Atmospheric Analysis: American Society for Testing and Materials, Philadelphia (1972), ASTM Standard D992-71, “Standard Method of Test for Nitrate Ion in Water,” pp 124-126.
- 1972 Annual Book of Standards, Part 30: General Test Methods: American Society for Testing and Materials, Philadelphia (1972), ASTM Standard E203-64, “Standard Method of Test for Water Using Karl Fischer Reagent,” pp 513-522.
- van der Zijden M. J., van Hinte J. E., and van den Ende J. C., J. Inst. Petroleum, 36, (1950) 561-574.
- “General Motors Response to the March 8, 1974, Federal Register Regarding Automotive Sulfate Emissions: A Status Report.” Prepared for the Environmental Protection Agency, May 7, 1974.
- Pierson W. R., Butler J. W., and Trayser D. A., “Nitrate and Nitric Acid Emissions From Catalyst-Equipped Automotive Systems.” Environmental Letters, 7, No. 3, (1974) 267-272.
- Conference on Impact of Mobile Emissions Controls, Cosponsored by National Institute of Environmental Health Sciences and National Environmental Research Center, EPA, Research Triangle Park, N. C., April 1974.
- Latimer W. M., and Hildebrand J. H., “Reference Book of Inorganic Chemistry,” 3rd Edition, New York: MacMillan, 1951, p 255.