N2O emissions from coal fired fluidized-bed combustion are approximately 30–360 mg/Nm, much higher than that from pulverized coal combustion (less than 30 mg/Nm). One approach to reduce the N2O is to reburn the biomass gasification gas in the coal-fired fluidized bed. In this paper, the effects of gasified biomass reburning on the integrated boiler system were investigated by both simulation an...

Environmental concerns over increased coal consumption are fully justified by the past history of coal use. Although improved technology has provided some safeguards, increased utilization will require mining practices, emission control technologies, and waste disposal procedures that are not yet fully integrated into the routine use of the coal energy system. The Committee on Health and Evniro...

The 1990 Clean Air Act Amendment (CAAA) empowered the U.S. Environmental Protection Agency (EPA) to set emission standards for a number of potentially hazardous air pollutants (HAPS) generated by a variety of specific combustion sources. Eleven elements (or compounds of these elements) present in coal are among the 189 pollutants identified as air toxics by the CAAA legislation. Mercury is incl...

Combustion system development in power generation is discussed ranging from the pre-environmental era in which the objectives were complete combustion with a minimum of excess air and the capability of scale up to increased boiler unit performances, through the environmental era (1970–), in which reduction of combustion generated pollution was gaining increasing importance, to the present and n...

This paper presents calculations of a pulverized coal flame and a coal-fired utility boiler with advanced combustion technologies. A combustion model based on an extended Eddy Dissipation Concept (EDC) combined with finite rate chemistry is described and some applications are shown. This model can be regarded as an extension of the previously used Eddy Breakup model (EBU) where infinite fast ch...

A comprehensive fireside corrosion project was undertaken to better understand the corrosion mechanisms operating on the lower furnace walls and superheaters in modern coal-fired utility boilers. Eight U.S. coals commonly burned in boilers have been selected to represent a wide range of coal chemistry. These coals will be burned in a pilot-scale combustion facility to closely simulate the actua...

Daily average PM(10) (particulate matter which passes through a size selective impactor inlet with a 50% efficiency cut-off at 10 microm aerodynamic diameter), TSP (total suspended particulate matter) and their chemical species mass concentrations were measured at residential and industrial sites of an urban region of Kolkata during November 2003-November 2004. Source apportionment using chemic...

The thermal reactivity and kinetics of five coal chars, a biomass char, and two coal/biomass char blends in an oxy-fuel combustion atmosphere (30%O2-70%CO2) were studied using the non-isothermal thermogravimetric method at three heating rates. Fuel chars were obtained by devolatilization in an entrained flow reactor at 1273 K under N2 and CO2 atmospheres.Three nth-order representative gas-solid...

A huge amount of coal is always stored in open spaces in coal-fired power plants before combustion. Mercury released from coal by rain or flowing water is an environmental risk and can cause contamination of the soil around the storage area. To better understand mercury pollution and to control mercury emission before combustion, it is necessary to determine the mobility and leaching characteri...

Coal blending is becoming increasingly common as more and more off-specification coals are received in coal-fired power plants, given the present coal market in China. This situation requires optimization of the operating parameters for matching the varying coal properties. The motivation for such optimization includes confirming good performance of the units regarding the security, the economy...