Correlating the Slagging of a Utility Boiler with Coal Characteristics

Hatt, Rod

doi:10.1007/978-1-4757-9223-2_15

Cited by 12 publications

(8 citation statements)

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“…Higher content of Na and K (as in the case of KFA) lowers the melting point of the ash, and hence, can enhance the deposition of the ash and fouling of the boiler tubes. The successful fuels have B/A < 0.11; intermediate fuels have B/A D 0.11; the unsuccessful fuels have B/A > 0.14 (Hatt, 1996). The lower content of un-burnt C in LFA than JFA and KFA is also indicative of better successfulness of the combustion of lignite than that of coal washery rejects and mustard stalk.…”

Section: Acid-base Reactionmentioning

confidence: 86%

The Mineralogical Characteristics of the Ashes Derived from the Combustion of Lignite, Coal Washery Rejects, and Mustard Stalk

Singh¹,

Ram²,

Sarkar³

2013

Energy Sources, Part A: Recovery, Utilization, and Environmenta

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With coal being the predominant and limited source of energy, extraction of energy from lignite, coalwashery rejects, and agro-wastes through combustion is being attempted globally. During combustion, minerals in the fuels undergo various transformations with corresponding impact on the process. Lignite fly ash, Jamadoba fly ash, and Kalptaru fly ash and corresponding fuels like lignite, coal-washery rejects, and mustard stalk from pulverized fuel, fluidized bed, and grate system of combustion at Neyveli, Jamadoba, Kalpataru, respectively, were characterized. Lignite has better fuel characteristics than washery rejects and mustard stalk. Of the major phases, SiO 2 , Al 2 O 3 , and CaO are common, besides Fe 2 O 3 in lignite fly ash and Jamadoba fly ash, and K 2 O in Kalptaru fly ash. Among minor phases, MgO, Na 2 O, SO 3 , P 2 O 5 , and TiO 2 are common, despite K 2 O in lignite fly ash and Jamadoba fly ash, and Fe 2 O 3 in Kalptaru fly ash. Other minerals are mullite, silicates, sulphates, and carbonates of Ca in lignite fly ash; K-Al-Si species in Jamadoba fly ash; K/Ca-Al-Si species, and sulphates and carbonates of Ca in Kalptaru fly ash. These minerals are the product of mineralogical transformations, where source and composition of the fuels and operating conditions are crucial. Overall the combustion of lignite is more successful than that of washery rejects and mustard.

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Section: Acid-base Reactionmentioning

confidence: 86%

The Mineralogical Characteristics of the Ashes Derived from the Combustion of Lignite, Coal Washery Rejects, and Mustard Stalk

Singh¹,

Ram²,

Sarkar³

2013

Energy Sources, Part A: Recovery, Utilization, and Environmenta

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“…The high amount of mineral matter (ash) leads to ash disposal problems, corrosion of boiler walls, fouling of economizers, high fly ash emissions, and several types of respiratory system diseases . It also creates problems for power stations, including erosion, difficulty in pulverization, poor emissivity as well as flame temperature, and low radioactivity transfer. , The occurrence of mineral matter in coal has been discussed by Ward . Several physical and chemical methods are used to remove mineral matter from coal through techniques such as gravimetrics, floatation, oxidation, and reduction. , Physical and chemical methods for demineralization are not so eco-friendly and produce secondary sludge .…”

Section: Introductionmentioning

confidence: 99%

“…4 It also creates problems for power stations, including erosion, difficulty in pulverization, poor emissivity as well as flame temperature, and low radioactivity transfer. 5,6 The occurrence of mineral matter in coal has been discussed by Ward. 7 Several physical and chemical methods are used to remove mineral matter from coal through techniques such as gravimetrics, floatation, oxidation, and reduction.…”

Section: Introductionmentioning

confidence: 99%

Demineralization Study of High-Ash Permian Coal with Pseudomonas mendocina strain B6-1: A Case Study of the South Karanpura Coalfield, Jharkhand, India

Kumar

Singh

Singh³

et al. 2018

Energy Fuels

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This paper entails the results of demineralization carried out on Karanpura Gondwana coals having high ash (30.57–21.80%) and low sulfur (0.29–0.20%) contents. The coal samples were subjected to demineralization using Pseudomonas mendocina strain B6-1, and the effect of various parameters, such as pH, temperature, incubation time, and pulp density, was observed. Optimum values of demineralization were found at pH 6.0, temperature of 35 °C, 6.0% (w/v) pulp density, and incubation time of 7 days. Reduction in the mineral matter (mean of 13.72–29.10%) content led to a relative increase in vitrinite, inertinite, and liptinite macerals. Further, the treatment has also caused an increase in the useful heat value, gross calorific value, and net calorific value of coal from 4824.86 to 5192.06 cal/g, from 5396.72 to 5647.47 cal/g, and from 5059.30 to 5273.80 cal/g (mean values), respectively. The method is eco-friendly and useful in obtaining clean fuel.

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“…Ash chemistry indices do not count the mineralogical mode of occurrence of the elements of concern and mineral associations, both of which are equally important as the ash chemistry in determination of slagging and fouling. With the above limitations, it can be seen from Table 1 that the values for most of the common ash deposition indices suggest that the lignite samples would have a high propensity to form ash deposits [8,9]. The values in bold and italics indicate high propensity for ash deposition.…”

Section: Correlation With Conventional Ash Deposition Indicesmentioning

confidence: 99%

Influence of Sorbent Characteristics on Fouling and Deposition in Circulating Fluid Bed Boilers Firing High Sulfur Indian Lignite

Palaniswamy¹,

Rajavel²,

Vinodhan³

et al. 2013

Journal of Combustion

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125 MWe circulating fluidized bed combustion (CFBC) boiler experienced severe fouling in backpass of the boiler leading to obstruction of gas flow passage, while using high sulfur lignite with sorbent, calcium carbonate, to capture sulfur dioxide. Optical microscopy of the hard deposits showed mainly anhydrite (CaSO4) and absence of intermediate phases such as calcium oxide or presence of sulfate rims on decarbonated limestone. It is hypothesized that loose unreacted calcium oxides that settle on tubes are subjected to recarbonation and further extended sulfation resulting in hard deposits. Foul probe tests were conducted in selected locations of backpass for five different compositions of lignite, with varied high sulfur and ash contents supplied from the mines along with necessary rates of sorbent limestone to control SO2, and the deposits build-up rate was determined. The deposit build-up was found increasing, with increase in ash content of lignite, sorbent addition, and percentage of fines in limestone. Remedial measures and field modifications to dislodge deposits on heat transfer surfaces, to handle the deposits in ash conveying system, and to control sorbent fines from the milling circuit are explained.

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Correlating the Slagging of a Utility Boiler with Coal Characteristics

Cited by 12 publications

References 0 publications

The Mineralogical Characteristics of the Ashes Derived from the Combustion of Lignite, Coal Washery Rejects, and Mustard Stalk

The Mineralogical Characteristics of the Ashes Derived from the Combustion of Lignite, Coal Washery Rejects, and Mustard Stalk

Demineralization Study of High-Ash Permian Coal with Pseudomonas mendocina strain B6-1: A Case Study of the South Karanpura Coalfield, Jharkhand, India

Influence of Sorbent Characteristics on Fouling and Deposition in Circulating Fluid Bed Boilers Firing High Sulfur Indian Lignite

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