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Catalytic Destruction of a Surrogate Organic Hazardous Air Pollutant as a Potential Co-benefit for Coal-fired Selective Catalyst Reduction Systems
Citation:
Lee, C., Y. Zhao, S. Lu, AND W. Stevens. Catalytic Destruction of a Surrogate Organic Hazardous Air Pollutant as a Potential Co-benefit for Coal-fired Selective Catalyst Reduction Systems. ENERGY AND FUELS. American Chemical Society, Washington, DC, 30(3):2240-2247, (2016).
Impact/Purpose:
Selective catalytic reduction (SCR) is the most widely used post-combustion NOx control technology in coal-fired power plants for meeting stringent NOx emission limits. Vanadium is the primary active component of commercial SCR catalysts. Vanadium was also found a reactive component in V2O5-WO3/TiO2 based catalysts for destruction of a wide variety of organic hazardous air pollutants(HAPs). We conducted bench-scale tests to evaluate the effects of operating parameters of coal-fired SCR units, i.e., temperature and space velocity and concentration of NH3, and the flue gas constituents from the combustion of bituminous and subbituminous coal, including SO2, NOx, and HCl, on the destruction of benzene as a surrogate organic HAPs. Test results showed significant desruction of benzene occurred under a broad range of SCR operating conditions, suggesting that a large number of coal-fired utility boilers which are equipped with SCR for NOx control have potential to achieve reduction of organic HAP emissions as a co-benefit.
Description:
Catalytic destruction of benzene (C6H6), a surrogate for organic hazardous air pollutants (HAPs) produced from coal combustion, was investigated using a commercial selective catalytic reduction (SCR) catalyst for evaluating the potential co-benefit of the SCR technology for reducing organic HAP emissions. Bench-scale experiments were performed using simulated coal combustion flue gases under a broad range of SCR reaction conditions. C6H6 was added at 1 or 17 ppm into the flue gas mixtures with different concentrations of sulfur dioxide (SO2), nitrogen oxide (NO), hydrogen chloride (HCl), and ammonia (NH3) to simulate the combustion of bituminous coal and subbituminous coal. The destruction of the C6H6 across the catalyst was measured by a total hydrocarbon analyzer and by a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-TOFMS) for the experiments with high (17 ppm) and low (1ppm) concentrations of C6H6, respectively. The operating parameters of the SCR process including space velocity, temperature, and the concentration of C6H6, were found to have a significant impact on the destruction of C6H6. The constituents of the flue gas had very little impact on the destruction, suggesting that the co-benefit of organic HAP destruction by the SCR process may be applicable to a wide variety of coals.
