Fundamental study of NO/sub x/ reduction processes during staged combustion of pulverized coal

Technical Report · Thu Dec 01 04:00:00 EST 1983

OSTI ID:5236389

Yang, R J; Himes, R M; Muzio, L J

Experimental testing of pulverized coal-fired two-stage combustion has been carried out to study the fundamental processes that govern the reduction of nitrogen oxides (NO/sub x/) emissions during staged combustion of pulverized coal. These tests were conducted in a 0.5 million Btu/hr vertically downward-fired furnace designed to simulate the combustion conditions in a large scale pulverized coal-fired furnace. Test results showed that first-stage air/fuel stoichiometry, second-stage flame zone temperature and mixing intensity were the three process variables that have the most significant effects on stack NO/sub x/ emissions from two-stage combustion. The level of stack NO/sub x/ emissions was found to be determined through the fast gas phase reactions occurring in the jet mixing layers between first-stage exhaust and the staging air in the second-stage flame zone. The contribution of char nitrogen was found to be insignificant in the second-stage processes which determine the level of NO/sub x/ emissions. These results also showed that once the operating conditions were optimized with respect to second-stage combustion, stack NO/sub x/ emissions were largely insensitive to the variation in the fuel-rich first-stage combustion conditions. Besides these process related findings, it was also observed that the property of coal, especially its caking tendencies, would play an important role in determining the applicability of two-stage pulverized coal combustion. For coals with high caking tendencies, the reactivity of coal may be severely reduced in the fuel-rich first stage due to coal particle surface deterioration that combustion efficiency may be lower than those resulting from unstaged combustion.

• Research Organization: KVB, Inc., Irvine, CA (USA). Research Applications Div.
• DOE Contract Number: AC22-81PC40271
• OSTI ID: 5236389
• Report Number(s): DOE/PC/40271-2; ON: DE84006480
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000 -- Coal
Lignite
& Peat-- Combustion
42 ENGINEERING
421000* -- Engineering-- Combustion Systems
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
COMBUSTION
COMBUSTION PRODUCTS
COMMINUTION
COMPUTER CODES
ENERGY SOURCES
FOSSIL FUELS
FUEL-AIR RATIO
FUELS
FURNACES
MASS BALANCE
MATERIALS
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
REDUCTION
SUBBITUMINOUS COAL
THERMOCHEMICAL PROCESSES