Abstract |
The study discussed in the report was divided into two major phases; (a) a field program in which real plumes from coal and oil-fired power stations can be tracked by aircraft to determine plume composition as a function of downwind distance, environmental factors and source parameters; and (b) a laboratory program in which flue gas effluents generated by a pilot plant furnace (oil and coal fired) can be studied under simulated field conditions. Plume sampling was conducted insofar as possible under pre-selected meteorological conditions. Plume location beyond the visible range was determined by an automatic conductivity analyzer. This technique enabled mapping of plume boundaries for distances up to 12 miles while simultaneously furnishing SO2 concentration values as a function of downwind distance. A pilot plant combustion system was designed, installed and calibrated. This equipment, operating at the 50,000 BTU per hour level, produces real flue gas effluents from the combination of either No. 6 oil or pulverized coal. A 42 cu-ft reaction chamber was constructed to investigate atmospheric behavior of SO2 from stack plumes under controlled temperature, humidity, and simulated solar irradiation. Bench scale experiments were performed in which quantum yields were determined for pure SO2 and mixtures of SO2 and O2 for various uv excitation levels, 2537 and 31000A, at ambient pressure. Test results were in general agreement with previous quantum yields cited in the literature. Extrapolation of data to the low concentration ranges to be examined later in this program suggests that the uncatalyzed homogeneous photochemical formation of SO3 may attain the significant level of 2.4 percent per hour. (Author) |