Nitrous Oxide Concentrations in Coal,Oil,and Gas Furnace Flames

Abstract

Concentrations of NzO. NO" CO z• and O, were determined along the axis of coal, oil. and gas flames in a 3 MW experimental furnace, for both single-stage and two-stage combustion conditions. Concentrations of NO, and NzO were found to be strongly correlated along the flames and in the flue gas samples, with approximately one mole of N 20 produced for every three moles of NO,. The resulls suggested that most of the NO, and N 20 arose from oxidation of fuel nitrogen , with highest concentrations observed in coal flames and lowest levels in the natural gas flame. Appr oximately 12 percent of fuel nitrogen was converted to N20 in coal and oil flames.Two-stage combustion, which produces a fuel-rich zone near the burner, substantially lowered emissions of both NO, and N 20 in the experimental flames. In most cases the rates of decline were similar for the two gases, suggesting that related processes could account for the reduction of these nitrogen oxides in fuel-rich flames. Staged combustion is seen as an effective method for controlling both N 20 and NO, emissions.

The Trend and Status of Energy Resources and Greenhouse Gas Emissions in the Malaysia Power Generation Mix

“…The majority of the world N 2 O emission is from agricultural soil management (74%) and secondly from stationary combustion (8%), particularly from the power plants [111]. N 2 O emission is a by-product of fuel combustion, arising from oxidation of fuel nitrogen [112]. Since coal contains a higher content of nitrogen, the highest concentrations of N 2 O are observed in coal flames and the lowest levels in the natural gas flame [113].…”

Kinetics of N2O formation/destruction from coal combustion at low temperatures

“…At the current rate of production, it is estimated that N O concentrations will reach roughly 375 ppb by the year 2030. This prospect has led many researchers (Pierotti and Rasmussen, 1976;Weiss and Craig, 1976;Elkine et al, 1978;Weiss, 1981;Keller et al, 1986;Hao et al, 1987;Roby and Bowman, 1987) to study N O emissions from natural and anthropogenic sources.…”

“…Various workers (Pierotti and Rasmussen, 1976;Weiss and Craig, 1976;Elkins et al, 1978;Weiss, 1981;Keller et al, 1986;Hao et al, 1987;Roby and Bowman, 1987;Hayhurst and Lawrence, 1992;Kramlich et al, 1982;Muzio et al, 1990;Smart et al, 1990;Kramlich et al, 1989;Martti et al, 1990;Bartok and Saro"m, 1991;Oude et al, 1992) have suggested the increasing trends of N O level in the atmosphere from the above-mentioned two sources and argued that combustion should represent an important anthropogenic input of N O to the atmosphere. The formation of N O from pulverized coal combustion has been studied by many researchers (Hayhurst and Lawrence, 1992;Kramlich et al, 1982;Muzio et al, 1990;Smart et al, 1990).…”

Role of Vehicular Catalytic Converter Temperature in Emission of Pollutants: An Assessment Based on Isotopic Analysis of CO2 and N2O

“…22,23 Under the high temperature and pressure of internal-combustion engines, N 2 formation is preferred over N 2 O. 24 N 2 O is formed at relatively low catalyst temperatures, and it decomposes at higher temperatures. 5,25,26 In contrast, Toyoda et al (ref 6) concluded from a set of automobile experiments that the emission is largely affected by the running speed, mileage, and the catalytic converter temperature of vehicles.…”

“…The formation and release are complex and depend critically on the types of emission regulators installed . One important process to control the emission is the chemical reduction of NO x through a three-way catalyst. ,− It was found that N 2 O emission from catalyst-equipped gasoline light-duty vehicles is affected significantly by the type and the temperature of the catalyst and is insensitive to the total NO x levels or the fuel nitrogen content. , Under the high temperature and pressure of internal-combustion engines, N 2 formation is preferred over N 2 O . N 2 O is formed at relatively low catalyst temperatures, and it decomposes at higher temperatures. ,, In contrast, Toyoda et al (ref ) concluded from a set of automobile experiments that the emission is largely affected by the running speed, mileage, and the catalytic converter temperature of vehicles.…”