NO{sub x} and SO{sub 2} emissions from pulverized coal and waste tire: The role of devolatilization and char combustion phases

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:435645

Atal, A; Steciak, J; Levendis, Y A ^[1]

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1. Northeastern Univ., Boston, MA (United States). Dept. of Mechanical Engineering

In this basic experimental study the NO{sub x} and SO{sub 2} emissions of waste tires and coal are contrasted. Experiments were conducted in a laboratory-scale drop-tube furnace by fluidizing powders of coal and tire crumb ({approx}200{micro}m) at different gas temperatures (1,400K--1,600K). Emissions of SO{sub 2}, H{sub 2}S, CO{sub 2}, CO, NO and NO{sub 2} were monitored at the exit of the furnace. Pyrometric and cinematographic observations revealed that the coal particles exhibited distinct volatile and char combustion phases, while tire particles exhibited a primary volatile phase followed by a char combustion phase, which was accompanied by simultaneous burning of heavier pyrolyzates. The total recorded combustion times were considerably shorter for tire particles primarily because of their lower density and lower char yield. At a gas temperature of 1450 K, primary volatile flame temperatures for both coal and tire were in the neighborhood of 2,200--2,400 K, while char temperatures were 2,000--2,100 K for the tire and 1,850--2,000 K for the coal particles. Mass burning experiments, under oxidizing conditions, showed that the SO{sub 2} and CO{sub 2} emissions of the pulverized bituminous coal used were comparable to those of the tire crumb. However, the amount of NO{sub x} released by coal was four times that released by the tire and in either case it did not vary with gas temperatures in the range of 1,400 to 1,600K. Co-firing of pulverized coal and tires resulted in NO{sub x} emissions proportional to the weight average of the blends. The nitrogen released during the volatile and char combustion phases of coal and tire crumb was proportional to the mass burned during each phase. Sulfur, however, was preferentially released during the devolatilization phase. The CO{sub 2} released during the devolatilization and combustion stages was, as expected, directly proportional to the amount of carbon in the volatiles and the char, respectively.

• Sponsoring Organization: Environmental Protection Agency, Washington, DC (United States)
• OSTI ID: 435645
• Report Number(s): CONF-951135--; ISBN 0-7918-1751-2
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
09 BIOMASS FUELS
AIR POLLUTION CONTROL
BITUMINOUS COAL
CHEMICAL REACTION YIELD
COCOMBUSTION
COMBUSTION KINETICS
DEVOLATILIZATION
EXPERIMENTAL DATA
NITROGEN OXIDES
SULFUR DIOXIDE
TIRES