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Bottom Ash (bottom + ash)
Selected AbstractsEmission of trace toxic metals during pulverized fuel combustion of Czech coalsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2003P. Danihelka Abstract A study of the trace elements emission (As, Se, Cd, Co, Cr, Cu, Zn, Hg, Tl, Pb, Ni, Sn, Sb, V, Mn and Fe) from pulverized coal combustion has been made at six heating and power stations situated in the Czech Republic. The amount of chlorine in coal has considerable influence on volatilization of some elements such as Zn, Cu, Pb, Hg and Tl, which is explained by the formation of thermodynamically stable compounds of these elements with chlorine. Generally, the affinities for Cl follows the order Tl > Cu > Zn > Pb > Co > Mn > Sn > Hg. The experimental data indicates enrichment of some of the trace toxic elements in the emissions (Cu, Zn, As, Se, Cd, Sn, Sb, Hg and Pb) and good agreement was obtained by thermodynamic equilibrium calculations with a few exceptions. In the case of Fe, Mn, Co, Cr and Sn calculated values are overestimated in the bottom ash and there are zero predicted amounts of these elements in the fly ash. In comparison, the results from experiments show up to 80% of these elements retained in fly ash. This implies that there exist additional steps leading to the enrichment by Fe, Mn, Co, Cr and Sn of small particles. Such mechanisms could include the ejection during devolatilization of small inorganic particles from the coal of bottom ash particles, or disintegration of the char containing these metals to small particles of fly ash. On the other hand, there are slightly overestimated or similar values of relative enrichment factors for As, V, Cu, Cd, Sb, Tl and Pb in the fly ashes and zero predicted values for bottom ashes. Our experimental results show about 5% or less of these elements are retained in bottom ashes, so they probably remain in the bottom ash inside unburned parts of coal. Copyright © 2003 John Wiley & Sons, Ltd. [source] Partitioning behavior of mercury during coal combustion: the influence of low-NOx burners and operation load of boilerASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2009Guang-Qian Luo Abstract Two 200 MW, pulverized bituminous coal-fired electric utility boilers each equipped with a five-field cold-side electrostatic precipitator (ESP) as the only air pollution control device (APCD) were investigated on mercury distribution and speciation under various conditions. With the same fuel consumption, both facilities are the same but with different burners, low-NOx type and conventional type. Sampling points of gaseous mercury and chlorine species were at the inlet and outlet of the ESP. The mercury concentrations in various solids, including parent coal, bottom slag, economizer bottom ash and fly ash in different hoppers of ESP, were sampled and analyzed. The Ontario Hydro Method was employed to detect mercury in flue gas, and HCl and Cl2 were detected by the EPA method 26. A series of tests were conducted on the boiler with low-NOx burners under various loads (70, 85 and 100% of full load) and on the other boiler with conventional burners under full load. Results showed that small amount of mercury remained in the solid combustion products and most of mercury was released into the atmosphere. The majority of the released mercury was in oxidized form. Burner types and load variation had effects on Cl species concentration in flue gas. Furthermore, particle diameter and carbon content and specific surface area of fly ash affected speciation and distribution of mercury and mercury removal efficiency of ESP. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Operation of a municipal solid waste co-combustion pilot plantASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2007V. K. C. Lee Abstract The co-combustion of municipal solid waste (MSW) is a novel and highly integrated design combining cement manufacturing, thermal processing of MSW and energy/electricity production (termed the Co-Co process). This novel design of the Co-Co process was developed in 2003,2004 and a pilot plant with a capacity of 40 tonnes per day was constructed and commissioned in 2005. The pilot plant was operated for a period of 10 weeks during 2005. Various feed protocols, namely, MSW as received and after removal of recyclables, were tested. Stack emissions were monitored either continuously (gas emission) or periodically (dioxins and heavy metal emissions). Solid residues including bottom ash and fly ash were also sampled and analysed for heavy metals and dioxins periodically. It was found that the levels of dioxins in the stack emissions and fly ash were below normal MSW thermal treatment processes, and government environmental and international limits (more than 1000 times less). Other gases, such CO, NOx, SOx and HCl, were also well below government environmental licence limits as defined by a best practical means (BPM). In addition, the materials recovery and recycling facility (MRRF) was tested. It demonstrated that different fractions, including metals, plastics and glass, of the MSW could be separated and recovered. The Co-Co process was successfully demonstrated and its emission levels were well below normal MSW thermal treatment processes. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Adsorption Behavior of Potassium Ion on Planting MaterialsCHINESE JOURNAL OF CHEMISTRY, Issue 9 2007Dechprasitthichokea Paunpassanan Abstract Characterization of planting materials used as adsorbent has been studied in order to compare potassium ion adsorption on two types of planting materials, which are a fired planting material (FPM) made from a mixture of 4 kinds of wastes (bottom ash, flue gas desulfurization (FGD) gypsum, paddy soil and sawdust) formed and fired at 850 °C and the commercial planting material called "hydroball" (HDB) bought from Jatujak market, Bangkok. The physical characteristics of both types of planting materials indicate that the FPM has a larger specific surface area than the HDB. The factors affecting potassium adsorption on both the planting materials such as an equilibration time and some solid/solution ratios were investigated. The suitable equilibration time for the adsorption to reach an equilibrium on the FPM and HDB is one and two hours, respectively. The highest amounts of potassium ion adsorbed on both the planting materials were obtained when the solid/solution ratio was 1:15. The adsorption behavior on both the planting materials tends to correspond with the Freundlich isotherm. [source] Emission of trace toxic metals during pulverized fuel combustion of Czech coalsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2003P. Danihelka Abstract A study of the trace elements emission (As, Se, Cd, Co, Cr, Cu, Zn, Hg, Tl, Pb, Ni, Sn, Sb, V, Mn and Fe) from pulverized coal combustion has been made at six heating and power stations situated in the Czech Republic. The amount of chlorine in coal has considerable influence on volatilization of some elements such as Zn, Cu, Pb, Hg and Tl, which is explained by the formation of thermodynamically stable compounds of these elements with chlorine. Generally, the affinities for Cl follows the order Tl > Cu > Zn > Pb > Co > Mn > Sn > Hg. The experimental data indicates enrichment of some of the trace toxic elements in the emissions (Cu, Zn, As, Se, Cd, Sn, Sb, Hg and Pb) and good agreement was obtained by thermodynamic equilibrium calculations with a few exceptions. In the case of Fe, Mn, Co, Cr and Sn calculated values are overestimated in the bottom ash and there are zero predicted amounts of these elements in the fly ash. In comparison, the results from experiments show up to 80% of these elements retained in fly ash. This implies that there exist additional steps leading to the enrichment by Fe, Mn, Co, Cr and Sn of small particles. Such mechanisms could include the ejection during devolatilization of small inorganic particles from the coal of bottom ash particles, or disintegration of the char containing these metals to small particles of fly ash. On the other hand, there are slightly overestimated or similar values of relative enrichment factors for As, V, Cu, Cd, Sb, Tl and Pb in the fly ashes and zero predicted values for bottom ashes. Our experimental results show about 5% or less of these elements are retained in bottom ashes, so they probably remain in the bottom ash inside unburned parts of coal. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||