Sumantra Bhattacharya - Academia.edu (original) (raw)

Papers by Sumantra Bhattacharya

Vikalpa, Mar 1, 2015

International Coal Pricing presents preliminary research, review of literature and comments on pu... more International Coal Pricing presents preliminary research, review of literature and comments on published papers or on any relevant subject C oal is a critical input for power, fertilizer, iron and steel (I&S) and the cement sector. At times up to 75 per cent of the power generated in India is coal fired. 1 Besides being used on a large scale as domestic and eateries fuel, coal also plays an important role in paper, brick kiln and chemical industries. Except for I&S, every other consumer uses coal primarily for its inherent thermal properties, that is, heat generated during combustion. That precisely is the reason why in international nomenclature, the terminology non-coking coal has been replaced by thermal coal. Apart from combustible material, coal also contains noncombustible impurities and is represented essentially by its ash content. Ash is the solid incombustible residue obtained after burning the coal. Moisture content is another negative quality parameter of coal. It could be either inherently present in coal or could get added during mining, cleaning, transport, stockpiling , etc. Coal price and pricing and its socioeconomic impact have become a major subject of concern and therefore for debate in recent times. For the first time in the modern history of India, coal has become an important political issue. Coal consumers in India believe that total moisture content in the coal used by them quite often is rather unreasonably high. All other negative quality parameters of coal, physical or chemical in nature, are in some or the other way associated with the ash content and ash composition of coal. INDIAN SCENARIO In India, coal is sold on the basis of grades, first conceived in the wake of World War I in 1917. Since nationalization, coal gradation and coal pricing have been controlled by the Union Ministry of Coal (MOC) and/or Coal India Ltd (CIL). Till 31 December 2011, non-coking coal grades used to be dependent on Useful Heat Value (UHV) expressed in kcal/kg as shown in Table 1. UHV took into account the heat trapped in ash (A) produced by burning the coal and the heat lost in removing the moisture (M) while burning the coal. Equal importance was assigned to the heat loss arising out of ash and moisture contents.

Advanced Powder Technology

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires

Choice of collector in coal flotation worldwide has been limited to kerosene and diesel oil. For ... more Choice of collector in coal flotation worldwide has been limited to kerosene and diesel oil. For various reasons, mostly related to reagent properties, the latter has been traditionally used in coal flotation in India. In a recent development, commercial synthetic collectors are being launched in the market. Objective of the present work is to compare between the performance of two collectors, diesel oil and one such commercial synthetic collector for the size fractions; -0.5+0.1mm &-0.1mm. These are the typical feed sizes in split feed coal flotation. The compa-rison was done on the basis of a flotation performance evaluation parameter called “Separation Efficiency Rate (SER)” and also the reagent cost.

Advanced Physical Chemistry Practical Guide, 2022

Transactions of the Indian Ceramic Society, 1994

The massive expansion of glass industry in India, especially sheet glass industry over the last 1... more The massive expansion of glass industry in India, especially sheet glass industry over the last 15 years has, of necessity, led to a tremendous growth in the demand for silica sand. Reserves of sup...

International Journal of Coal Preparation and Utilization, 2015

ABSTRACT A parameter “Settling Index (SI)” has been proposed mathematically. The index was used t... more ABSTRACT A parameter “Settling Index (SI)” has been proposed mathematically. The index was used to evaluate the performance of the flocculation studies of coal fines in the tailings collected from a coal preparation plant of India. Effect of the process parameters on the settling rate were investigated using anionic polyacrylamide as the flocculant at the following parameter levels: Pulp density: 6–12% solids (w/w); slurry pH: 4–10; and flocculant dosage: 6.5–26 g/t-solid. The optimum conditions for settling were obtained at the flocculant dosage of 19.5 gpt, pH 8, and pulp density of 8% solid (w/w) and showed a settling rate about 168 mm/min. At the optimum condition of settling rate, the density of settled slurry was 40.84% solid (w/w). The Settling Index was found to be a useful tool for analyzing the settling performance. An empirical model was developed using the experimental settling rate data with an R2 value of .929.

Coal Preparation, 2007

Thermal coal, which is the mainstay of India's power generation, contains as high as 50% ash... more Thermal coal, which is the mainstay of India's power generation, contains as high as 50% ash. To meet the rapidly growing demand for thermal power, the transportation facilities need to be significantly expanded. Major routes of Indian Railways are currently saturated. Creation of transport infrastructure is expensive. Beneficiation of coal is known to improve its quality and consistency. The present work examines the impact of beneficiation on thermal coal transportation by railways and finds that it would considerably improve the loading capacity of wagons, their life and also “release” carrying capacity on the saturated rail network.

Coal Preparation, 2007

ABSTRACT Two high-rank coking coals of drift origin, which exhibited strong natural hydrophobicit... more ABSTRACT Two high-rank coking coals of drift origin, which exhibited strong natural hydrophobicity, were used in this work. As high as 64–74% yield could be achieved through collectorless batch flotation with three different frothers: pine oil, MIBC, and a synthetic frother for three different feed sizes. It appears that a fairly long wetting time minimized the frother consumption. The flotation response of three different sizes, − 0.5 mm, − 0.5 + 0.1 mm, and − 0.1 mm of the same feed, was found to be different for the three frothers. Frother performance was also found to vary with the same size of the two coals. The performance of the synthetic frother and MIBC was found to be superior for the − 0.5 + 0.1 mm and − 0.1 mm feeds, respectively. MIBC performed best for the − 0.5 mm feed of one coal, whereas the synthetic frother did the same for the other coal. Frother performance also seems to be dependent on performance evaluation methodology.

Journal of the Southern African Institute of Mining and Metallurgy, 2019

An ideal procedure to determine the limits of flotation-based separation, as is the case with was... more An ideal procedure to determine the limits of flotation-based separation, as is the case with washability analysis for density separation, does not exist. Therefore, a procedure called release analysis, considered to be the counterpart of the washability process in density separation, was developed to evaluate the flotation characteristics of coal fines. Since flotation is a complex process it is necessary to know the maximum recoverable yield that could be achieved at a target ash level and what could be obtained by release analysis. Due to a number of limitations in the initial procedures, modifications were recommended by various researchers to generate an optimum separation curve. This paper presents a review of, and a discussion on, the chronological evolution of release analysis methodology over the decades. Notwithstanding the availability of a standardized release analysis procedure, such as BS 7530, the paper highlights the critical parameters involved in the procedures, such as coal type, feed characteristics, choice of reagents and dosage, operator bias, and design features of the flotation cell.

ArXiv, 2022

Events in turbulent flows computed by direct numerical simulation (DNS) are often calibrated with... more Events in turbulent flows computed by direct numerical simulation (DNS) are often calibrated with properties based on homogeneous isotropic turbulence, advanced by Kolmogorov, and given in Turbulence, U. Frisch, Cambridge Univ. Press, UK (1995). However, these computational procedures are not calibrated using numerical analyses in order to assess their strengths and weaknesses for DNS. This is with the exception in "A critical assessment of simulations for transitional and turbulence flows- Sengupta, T.K., In Proc. of IUTAM Symp. on Advances in Computation, Modeling and Control of Transitional and Turbulent Flows, 491-532, (eds. Sengupta, Lele, Sreenivasan, Davidson), WSPC, Singapore (2016)", where such a calibration has been advocated for numerical schemes using global spectral analysis (GSA) for the convection equation. In recent times, due to growing computing power, simulations have been reported using pseudo-spectral methods, with spatial discretization performed in F...

Mineral Processing and Extractive Metallurgy Review, 2004

... Glembotskii , VA , Dmitrieva , GM , and Sorokin , MM 1970 , Non Polar Flotation Agents Part I... more ... Glembotskii , VA , Dmitrieva , GM , and Sorokin , MM 1970 , Non Polar Flotation Agents Part II , Jerusalem , Israel Program for Scientific Translations . ... Recovery showed negligible variation with temperature, 6% for Bulli and Greta Seams and 3% for Victoria Tunnel Seam. ...

Separation efficiency of coal cleaning equipment is typically assessed by Probable Error in Separ... more Separation efficiency of coal cleaning equipment is typically assessed by Probable Error in Separation (Ep) and Organic Efficiency (Eorg). The first one is determined on the basis of precise cut point density of separation and implies that for ideal separation the error is zero. The second one is calculated on the basis of yield of clean coal/ middling at the target ash and implies that for ideal separation the efficiency is 100%. Plant operators worldwide being accountable for the tonnage of the clean coal and middling produced regularly monitor Eorg with some application in plant design in India. Ep is universally used as an equipment selection criterion from among the vendors, in commercial contracts and sometimes for performance analysis of coal cleaning equipment carried out at the plants. Since both are performance measures there should possibly be a relationship between the two for specific cleaning equipment or for a particular type of density separators. Such relationships ...

International Journal of Coal Preparation and Utilization

The particle size and reagents are the most important parameter in flotation performance. Flotati... more The particle size and reagents are the most important parameter in flotation performance. Flotation kinetics models are used to define the rate of flotation and ultimate recovery. In this paper, fl...

On 21st May 2020, the Ministry of Environment, Forest & Climate Change (MoEFCC) issued a notifica... more On 21st May 2020, the Ministry of Environment, Forest & Climate Change (MoEFCC) issued a notification negating its own notification of 2nd January 2014 doing away with the use and supply of washed (and blended) coal of ash content not over 34% to power plants located 500 km from the supply sources and also for those located in urban and ecologically sensitive locations, and allowing coal of any ash content to be supplied to the power stations. The new notification of MoEFCC dated 21st May 2020 is based on inaccurate representations and baseless arguments put forward by Ministries of Coal, Power and NITI Aayog. Therefore, on the face of it this notification is a retrograde step as this would lead to irreparable damage not only to coal-red power plants but also to the ecology in and around power stations. This will also have adverse impact on India's ability to meet the commitment made at the Paris Climate Treaty of reducing the GHG emissions to pre-2005 level, by 2030. In view o...

The purpose of this study is to investigate the effect of coal properties on heat release rate an... more The purpose of this study is to investigate the effect of coal properties on heat release rate and combustion characteristics of coal. Coal sample of the same source was separated based on its size and was subjected to proximate analysis, gross calorific value determination and thermogravimetric analysis to study its combustion behavior. Experimental results show that each size fraction of coal, as typically fired in a power station, has substantially different proximate analysis result and burning profile. Ash content of coal varied from 30.3%-37.2% when the coal size varied from +50 mm to -2.54 mm. Combustion studies show that maximum coal burning rate (DTG max) also varied significantly, from 6.28% to 7.19%, size by size. Maximum burning rate data indicates that an increase in ash content from 30% to 37%, leads to burning time increase from 13.91 to 15.96 minute per kg of coal.

International Journal of Coal Preparation and Utilization

International Journal of Coal Science & Technology

This work presents the analysis of combustion characteristics of high ash Indian coal (28%–40%) c... more This work presents the analysis of combustion characteristics of high ash Indian coal (28%–40%) collected from different mines of Singaurali coalfield, India. All the coal samples were characterized by proximate and gross calorific value analysis. Combustion performance of the coals were characterised using thermo-gravimetric analysis to identify the burning profile of individual coals. Various combustion kinetic parameters such as ignition temperature, peak temperature and burnout temperature, ignition index and burnout index, combustion performance index plus rate and intensity index of combustion process, activation energy were determined to analyse the combustion behaviour of coal. Further all these combustion properties were compared with the volatile matter, ash, fixed carbon and fuel ratio of each coal. Theoretical analysis shows that with increase in ash content, combustion performance initially increases and later descends. Further, coal with (25 ± 1.75)% volatile matter, 2...

International Journal of Coal Science & Technology

Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields, India. Direc... more Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields, India. Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable volatile matter required for combustion. In the present work, experimental studies have been carried out to investigate the possible utilization of such heat-affected coal in thermal utilities by blending with other coal. Heat-affected coal (31% ash and 5300 kcal/kg GCV) collected from Jharia coalfield were blended with thermal coal (28% ash and 5650 kcal/kg GCV) in different ratios of 90:10, 80:20, 70:30 and 60:40 to identify the desirable blend ratio for burning of blended coal in thermal utilities. Burning characteristics of all the coals were carried out using TGA. Various combustion parameters such as ignition temperature, peak temperature, burnout temperature, ignition index, burnout index, combustion performance index, rate and heat intensity index of the combusti...

International Journal of Coal Preparation and Utilization

Release analysis is used to characterize the cleaning ability of coal fines. It defines the limit... more Release analysis is used to characterize the cleaning ability of coal fines. It defines the limit of separation at any target level of ash. Since flotation depends upon many factors like feed size ...

International Journal of Coal Science & Technology, Mar 27, 2020

This work presents the analysis of combustion characteristics of high ash Indian coal (28%-40%) c... more This work presents the analysis of combustion characteristics of high ash Indian coal (28%-40%) collected from different mines of Singaurali coalfield, India. All the coal samples were characterized by proximate and gross calorific value analysis. Combustion performance of the coals were characterised using thermo-gravimetric analysis to identify the burning profile of individual coals. Various combustion kinetic parameters such as ignition temperature, peak temperature and burnout temperature, ignition index and burnout index, combustion performance index plus rate and intensity index of combustion process, activation energy were determined to analyse the combustion behaviour of coal. Further all these combustion properties were compared with the volatile matter, ash, fixed carbon and fuel ratio of each coal. Theoretical analysis shows that with increase in ash content, combustion performance initially increases and later descends. Further, coal with (25 ± 1.75)% volatile matter, 20%-35% ash and fuel ratio 1.4-1.5 were found to be optimum for coal combustion.

Vikalpa, Mar 1, 2015

International Coal Pricing presents preliminary research, review of literature and comments on pu... more International Coal Pricing presents preliminary research, review of literature and comments on published papers or on any relevant subject C oal is a critical input for power, fertilizer, iron and steel (I&S) and the cement sector. At times up to 75 per cent of the power generated in India is coal fired. 1 Besides being used on a large scale as domestic and eateries fuel, coal also plays an important role in paper, brick kiln and chemical industries. Except for I&S, every other consumer uses coal primarily for its inherent thermal properties, that is, heat generated during combustion. That precisely is the reason why in international nomenclature, the terminology non-coking coal has been replaced by thermal coal. Apart from combustible material, coal also contains noncombustible impurities and is represented essentially by its ash content. Ash is the solid incombustible residue obtained after burning the coal. Moisture content is another negative quality parameter of coal. It could be either inherently present in coal or could get added during mining, cleaning, transport, stockpiling , etc. Coal price and pricing and its socioeconomic impact have become a major subject of concern and therefore for debate in recent times. For the first time in the modern history of India, coal has become an important political issue. Coal consumers in India believe that total moisture content in the coal used by them quite often is rather unreasonably high. All other negative quality parameters of coal, physical or chemical in nature, are in some or the other way associated with the ash content and ash composition of coal. INDIAN SCENARIO In India, coal is sold on the basis of grades, first conceived in the wake of World War I in 1917. Since nationalization, coal gradation and coal pricing have been controlled by the Union Ministry of Coal (MOC) and/or Coal India Ltd (CIL). Till 31 December 2011, non-coking coal grades used to be dependent on Useful Heat Value (UHV) expressed in kcal/kg as shown in Table 1. UHV took into account the heat trapped in ash (A) produced by burning the coal and the heat lost in removing the moisture (M) while burning the coal. Equal importance was assigned to the heat loss arising out of ash and moisture contents.

Advanced Powder Technology

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires

Choice of collector in coal flotation worldwide has been limited to kerosene and diesel oil. For ... more Choice of collector in coal flotation worldwide has been limited to kerosene and diesel oil. For various reasons, mostly related to reagent properties, the latter has been traditionally used in coal flotation in India. In a recent development, commercial synthetic collectors are being launched in the market. Objective of the present work is to compare between the performance of two collectors, diesel oil and one such commercial synthetic collector for the size fractions; -0.5+0.1mm &-0.1mm. These are the typical feed sizes in split feed coal flotation. The compa-rison was done on the basis of a flotation performance evaluation parameter called “Separation Efficiency Rate (SER)” and also the reagent cost.

Advanced Physical Chemistry Practical Guide, 2022

Transactions of the Indian Ceramic Society, 1994

The massive expansion of glass industry in India, especially sheet glass industry over the last 1... more The massive expansion of glass industry in India, especially sheet glass industry over the last 15 years has, of necessity, led to a tremendous growth in the demand for silica sand. Reserves of sup...

International Journal of Coal Preparation and Utilization, 2015

ABSTRACT A parameter “Settling Index (SI)” has been proposed mathematically. The index was used t... more ABSTRACT A parameter “Settling Index (SI)” has been proposed mathematically. The index was used to evaluate the performance of the flocculation studies of coal fines in the tailings collected from a coal preparation plant of India. Effect of the process parameters on the settling rate were investigated using anionic polyacrylamide as the flocculant at the following parameter levels: Pulp density: 6–12% solids (w/w); slurry pH: 4–10; and flocculant dosage: 6.5–26 g/t-solid. The optimum conditions for settling were obtained at the flocculant dosage of 19.5 gpt, pH 8, and pulp density of 8% solid (w/w) and showed a settling rate about 168 mm/min. At the optimum condition of settling rate, the density of settled slurry was 40.84% solid (w/w). The Settling Index was found to be a useful tool for analyzing the settling performance. An empirical model was developed using the experimental settling rate data with an R2 value of .929.

Coal Preparation, 2007

Thermal coal, which is the mainstay of India's power generation, contains as high as 50% ash... more Thermal coal, which is the mainstay of India's power generation, contains as high as 50% ash. To meet the rapidly growing demand for thermal power, the transportation facilities need to be significantly expanded. Major routes of Indian Railways are currently saturated. Creation of transport infrastructure is expensive. Beneficiation of coal is known to improve its quality and consistency. The present work examines the impact of beneficiation on thermal coal transportation by railways and finds that it would considerably improve the loading capacity of wagons, their life and also “release” carrying capacity on the saturated rail network.

Coal Preparation, 2007

ABSTRACT Two high-rank coking coals of drift origin, which exhibited strong natural hydrophobicit... more ABSTRACT Two high-rank coking coals of drift origin, which exhibited strong natural hydrophobicity, were used in this work. As high as 64–74% yield could be achieved through collectorless batch flotation with three different frothers: pine oil, MIBC, and a synthetic frother for three different feed sizes. It appears that a fairly long wetting time minimized the frother consumption. The flotation response of three different sizes, − 0.5 mm, − 0.5 + 0.1 mm, and − 0.1 mm of the same feed, was found to be different for the three frothers. Frother performance was also found to vary with the same size of the two coals. The performance of the synthetic frother and MIBC was found to be superior for the − 0.5 + 0.1 mm and − 0.1 mm feeds, respectively. MIBC performed best for the − 0.5 mm feed of one coal, whereas the synthetic frother did the same for the other coal. Frother performance also seems to be dependent on performance evaluation methodology.

Journal of the Southern African Institute of Mining and Metallurgy, 2019

An ideal procedure to determine the limits of flotation-based separation, as is the case with was... more An ideal procedure to determine the limits of flotation-based separation, as is the case with washability analysis for density separation, does not exist. Therefore, a procedure called release analysis, considered to be the counterpart of the washability process in density separation, was developed to evaluate the flotation characteristics of coal fines. Since flotation is a complex process it is necessary to know the maximum recoverable yield that could be achieved at a target ash level and what could be obtained by release analysis. Due to a number of limitations in the initial procedures, modifications were recommended by various researchers to generate an optimum separation curve. This paper presents a review of, and a discussion on, the chronological evolution of release analysis methodology over the decades. Notwithstanding the availability of a standardized release analysis procedure, such as BS 7530, the paper highlights the critical parameters involved in the procedures, such as coal type, feed characteristics, choice of reagents and dosage, operator bias, and design features of the flotation cell.

ArXiv, 2022

Events in turbulent flows computed by direct numerical simulation (DNS) are often calibrated with... more Events in turbulent flows computed by direct numerical simulation (DNS) are often calibrated with properties based on homogeneous isotropic turbulence, advanced by Kolmogorov, and given in Turbulence, U. Frisch, Cambridge Univ. Press, UK (1995). However, these computational procedures are not calibrated using numerical analyses in order to assess their strengths and weaknesses for DNS. This is with the exception in "A critical assessment of simulations for transitional and turbulence flows- Sengupta, T.K., In Proc. of IUTAM Symp. on Advances in Computation, Modeling and Control of Transitional and Turbulent Flows, 491-532, (eds. Sengupta, Lele, Sreenivasan, Davidson), WSPC, Singapore (2016)", where such a calibration has been advocated for numerical schemes using global spectral analysis (GSA) for the convection equation. In recent times, due to growing computing power, simulations have been reported using pseudo-spectral methods, with spatial discretization performed in F...

Mineral Processing and Extractive Metallurgy Review, 2004

... Glembotskii , VA , Dmitrieva , GM , and Sorokin , MM 1970 , Non Polar Flotation Agents Part I... more ... Glembotskii , VA , Dmitrieva , GM , and Sorokin , MM 1970 , Non Polar Flotation Agents Part II , Jerusalem , Israel Program for Scientific Translations . ... Recovery showed negligible variation with temperature, 6% for Bulli and Greta Seams and 3% for Victoria Tunnel Seam. ...

Separation efficiency of coal cleaning equipment is typically assessed by Probable Error in Separ... more Separation efficiency of coal cleaning equipment is typically assessed by Probable Error in Separation (Ep) and Organic Efficiency (Eorg). The first one is determined on the basis of precise cut point density of separation and implies that for ideal separation the error is zero. The second one is calculated on the basis of yield of clean coal/ middling at the target ash and implies that for ideal separation the efficiency is 100%. Plant operators worldwide being accountable for the tonnage of the clean coal and middling produced regularly monitor Eorg with some application in plant design in India. Ep is universally used as an equipment selection criterion from among the vendors, in commercial contracts and sometimes for performance analysis of coal cleaning equipment carried out at the plants. Since both are performance measures there should possibly be a relationship between the two for specific cleaning equipment or for a particular type of density separators. Such relationships ...

International Journal of Coal Preparation and Utilization

The particle size and reagents are the most important parameter in flotation performance. Flotati... more The particle size and reagents are the most important parameter in flotation performance. Flotation kinetics models are used to define the rate of flotation and ultimate recovery. In this paper, fl...

On 21st May 2020, the Ministry of Environment, Forest & Climate Change (MoEFCC) issued a notifica... more On 21st May 2020, the Ministry of Environment, Forest & Climate Change (MoEFCC) issued a notification negating its own notification of 2nd January 2014 doing away with the use and supply of washed (and blended) coal of ash content not over 34% to power plants located 500 km from the supply sources and also for those located in urban and ecologically sensitive locations, and allowing coal of any ash content to be supplied to the power stations. The new notification of MoEFCC dated 21st May 2020 is based on inaccurate representations and baseless arguments put forward by Ministries of Coal, Power and NITI Aayog. Therefore, on the face of it this notification is a retrograde step as this would lead to irreparable damage not only to coal-red power plants but also to the ecology in and around power stations. This will also have adverse impact on India's ability to meet the commitment made at the Paris Climate Treaty of reducing the GHG emissions to pre-2005 level, by 2030. In view o...

The purpose of this study is to investigate the effect of coal properties on heat release rate an... more The purpose of this study is to investigate the effect of coal properties on heat release rate and combustion characteristics of coal. Coal sample of the same source was separated based on its size and was subjected to proximate analysis, gross calorific value determination and thermogravimetric analysis to study its combustion behavior. Experimental results show that each size fraction of coal, as typically fired in a power station, has substantially different proximate analysis result and burning profile. Ash content of coal varied from 30.3%-37.2% when the coal size varied from +50 mm to -2.54 mm. Combustion studies show that maximum coal burning rate (DTG max) also varied significantly, from 6.28% to 7.19%, size by size. Maximum burning rate data indicates that an increase in ash content from 30% to 37%, leads to burning time increase from 13.91 to 15.96 minute per kg of coal.

International Journal of Coal Preparation and Utilization

International Journal of Coal Science & Technology

This work presents the analysis of combustion characteristics of high ash Indian coal (28%–40%) c... more This work presents the analysis of combustion characteristics of high ash Indian coal (28%–40%) collected from different mines of Singaurali coalfield, India. All the coal samples were characterized by proximate and gross calorific value analysis. Combustion performance of the coals were characterised using thermo-gravimetric analysis to identify the burning profile of individual coals. Various combustion kinetic parameters such as ignition temperature, peak temperature and burnout temperature, ignition index and burnout index, combustion performance index plus rate and intensity index of combustion process, activation energy were determined to analyse the combustion behaviour of coal. Further all these combustion properties were compared with the volatile matter, ash, fixed carbon and fuel ratio of each coal. Theoretical analysis shows that with increase in ash content, combustion performance initially increases and later descends. Further, coal with (25 ± 1.75)% volatile matter, 2...

International Journal of Coal Science & Technology

Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields, India. Direc... more Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields, India. Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable volatile matter required for combustion. In the present work, experimental studies have been carried out to investigate the possible utilization of such heat-affected coal in thermal utilities by blending with other coal. Heat-affected coal (31% ash and 5300 kcal/kg GCV) collected from Jharia coalfield were blended with thermal coal (28% ash and 5650 kcal/kg GCV) in different ratios of 90:10, 80:20, 70:30 and 60:40 to identify the desirable blend ratio for burning of blended coal in thermal utilities. Burning characteristics of all the coals were carried out using TGA. Various combustion parameters such as ignition temperature, peak temperature, burnout temperature, ignition index, burnout index, combustion performance index, rate and heat intensity index of the combusti...

International Journal of Coal Preparation and Utilization

Release analysis is used to characterize the cleaning ability of coal fines. It defines the limit... more Release analysis is used to characterize the cleaning ability of coal fines. It defines the limit of separation at any target level of ash. Since flotation depends upon many factors like feed size ...

International Journal of Coal Science & Technology, Mar 27, 2020

This work presents the analysis of combustion characteristics of high ash Indian coal (28%-40%) c... more This work presents the analysis of combustion characteristics of high ash Indian coal (28%-40%) collected from different mines of Singaurali coalfield, India. All the coal samples were characterized by proximate and gross calorific value analysis. Combustion performance of the coals were characterised using thermo-gravimetric analysis to identify the burning profile of individual coals. Various combustion kinetic parameters such as ignition temperature, peak temperature and burnout temperature, ignition index and burnout index, combustion performance index plus rate and intensity index of combustion process, activation energy were determined to analyse the combustion behaviour of coal. Further all these combustion properties were compared with the volatile matter, ash, fixed carbon and fuel ratio of each coal. Theoretical analysis shows that with increase in ash content, combustion performance initially increases and later descends. Further, coal with (25 ± 1.75)% volatile matter, 20%-35% ash and fuel ratio 1.4-1.5 were found to be optimum for coal combustion.