Coal Ash Deposition in Boilers

Borio, R.W.; Levasseur, A.A.

doi:10.1021/bk-1986-0301.ch021

Cited by 11 publications

(10 citation statements)

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“…During the combustion or gasification of coal, most of these alkali compounds are released into the gas phase and are usually present in the form of chlorides and sulfates. The vaporized alkali later condenses on various parts of the reactor and are a major cause o f fouling (Borio and Levasseur, 1986). One example is the alkali-induced corrosion in combined cycle processes where the hot flue gases come in contact with ceramic turbine materials.…”

Section: Introductionmentioning

confidence: 99%

High‐temperature adsorption of alkali vapors on solid sorbents

1989

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Vapors of alkali metal compounds can be removed from coal combustion and gasification flue gases using high-temperature aluminosilicate sorbents. The fundamentals of alkali adsorption on kaolinite, bauxite, and emathlite are compared and analyzed both experimentally and through theoretical modeling. The results show that the process is not a simple physical condensation, but a complex combination of diffusion and reaction. The kinetics of adsorption on these sorbents have similarities: the process is diffusion-influenced, the rate decreases with time, and there is a final saturation limit. There are, however, differences in reaction mechanisms leading to potentially different applications for each sorbent. In adsorbing alkali chloride vapors, kaolinite and emathlite release all the chlorine back to the gas phase while bauxite retains some of the chlorine. Moreover, the products of reaction with emathlite have a melting point significantly lower than those for kaolinite and bauxite. Therefore, emathlite is more suitable for lower-temperature sorption systems downstream of the combustors / gasifiers, while kaolinite and bauxite are suitable as in-sito additives.

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Section: Introductionmentioning

confidence: 99%

High‐temperature adsorption of alkali vapors on solid sorbents

1989

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“…The initial deformation temperature (IDT) for all the four ash samples were higher than 1500°C. The high AFT values are due to presence of high concentration of silica and alumina and appreciable amount of TiO 2 whose melting temperatures range between 1685 and 1775°C (Borio and Levasseur 1984). Therefore, coal of the four seams of Tentulai Block, Talcher coalfield is good for combustion with very little possibility of ash fusibility at fuel bed of the boiler.…”

Section: Ash Fusion Temperaturesmentioning

confidence: 99%

Distribution of mineral species in different coal seams of Talcher coalfield and its transformation behavior at varying temperatures

Banerjee

Mishra

Mohanty

et al. 2016

Int J Coal Sci Technol

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Mineral phase characterization and thorough understanding of its transformation behavior during combustion are imperative to know the potential utilization of coal in the thermal industries. The primary objective of this work is to analyze the quality of Indian Coals and obtain their mineral species-specific information at different depths. The samples were obtained from Talcher Coalfield, Odisha, India. Coal from four seam sections in the Talcher coalfield, India are mainly high ash coal ([50 %) and volatile matter deceases along with the seam depth. XRD results show that the major mineral phases present in the coal are quartz and kaolinite. Siderite, illite, and anatase were found in minor quantities. It has been observed that the clay minerals (kaolinite, silimanite, illite) decompose at higher temperature and traces of dolomite, mullite, hematite etc. are formed during the process of combustion. Among the four seams (M2, M12, M24 and M43) studied, ash of M43 has high Al 2 O 3 %, TiO 2 % and K 2 O% content and low SiO 2 %, CaO% and MgO% content. High acidto-base ratios contributed to high ash fusion temperatures (IDT [ 1500°C) and low slagging potential of the coals studied. Relatively low fouling index (\0.3) was estimated for all the coal seams studied. Furthermore, thermodynamic modeling software, FactSage, have been used to envision the mineral phase transformations that take place between 800 and 1500°C during coal combustion.

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“…The common manifestation of a deposition problem is the reduced heat transfer [1], so the fault would be simulated by changing the heat transfer coefficient. Here, Fig.…”

Section: Fault Simulationmentioning

confidence: 99%

“…In general, the ash deposition effects are interrelated. For example, ash deposition on convection tubes can reduce the cross-sectional flow area, increasing fan requirements and creating higher local gas velocities, which accelerates fly ash erosion [1,2]. These problems can result in unscheduled outages, reduced availability, costly modifications, and reduced generating capacity.…”

Section: Introductionmentioning

confidence: 99%

Fault simulation of boiler heating surface ash deposition in a power plant system

Zhang

Ming

2011

Front. Energy

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The simulation model of a power generation system was developed based on EASY5 simulation platform. The performances of the power plant under the conditions of the furnace slagging and ash deposition of the heating surfaces in the boiler were simulated. The results show that the simulation model can reasonably reflect the characteristics of the power plant when each component is under fault conditions. Through fault simulation, the change of the performance parameters can be obtained, which can be used in fault diagnosis system as the diagnosis criterion for expert system.

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Coal Ash Deposition in Boilers

Cited by 11 publications

References 0 publications

High‐temperature adsorption of alkali vapors on solid sorbents

High‐temperature adsorption of alkali vapors on solid sorbents

Distribution of mineral species in different coal seams of Talcher coalfield and its transformation behavior at varying temperatures

Fault simulation of boiler heating surface ash deposition in a power plant system

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