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11 results on '"Asfar Mobin Khan"'

1. TGA/DSC study to characterise and classify coal seams conforming to susceptibility towards spontaneous combustion

Author

Niroj Kumar Mohalik, Somu Mandal, Santosh Kumar Ray, Asfar Mobin Khan, Debashish Mishra, and Jai Krishna Pandey

Subjects
Coal, TGA/DSC, Spontaneous combustion, TG ignition, Mining engineering. Metallurgy, TN1-997
Abstract

Thermogravimetric analysis/differential scanning calorimeter (TGA/DSC) technique along with basic coal characteristics study is carried out for eighty coal samples of Indian coalfields, to determine spontaneous combustion propensity behaviour of coal. TGA study of coal samples indicates that there is an increase in the mass of coal samples in the temperature range 150–350 ℃, which may be due to oxygen adsorption and absorption. The correlation and principal component analysis states that the component of proximate analysis (Mad, VMd, FR, and VR) have an acceptable correlation with the TGA experiments results i.e., Tgsh and Tgign. Multiple fixed nonlinear regression analysis shows that thermogravimetry (TG) experiment results Tgign may be the best index to categorise/classify the coal as per their susceptibility towards spontaneous combustion. The authors proposed four groups of classification as per their propensity towards spontaneous combustion depending upon the moisture (Mad), volatile matter (VMd), and TG ignition temperature from differential thermogravimetric (DTG) curve (Tgign) using hierarchal clustering analysis. The coal samples of different seams from Indian coalfield may be classified into four different clusters, viz. very highly/extremely susceptible (Tgign 320 ℃). The field observations and TGA/DSC experiment results with the following statistical analysis substantiate a similar assessment.

Published
2022
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2. CFD modeling to study the effect of particle size on dispersion in 20l explosion chamber: An overview

Author

Santosh Kumar Ray, Niroj Kumar Mohalik, Asfar Mobin Khan, Debashish Mishra, Nikhil Kumar Varma, Jai Krishna Pandey, and Pradeep Kumar Singh

Subjects
Coal dust explosibility, CFD, 20l explosion chamber, Dispersion, Turbulent kinetic energy, Mining engineering. Metallurgy, TN1-997
Abstract

Mine disasters occur predominantly due to methane or coal dust explosion or a combination of both. Among the top ten worst coal mine disasters in India, nine are due to coal dust explosion. The current paper describes a general overview of the parameters causing dispersion leading to coal dust explosion, and computational fluid dynamics (CFD) simulation study to observe the effects of particle size on dispersion in Indian coal mines. Turbulent kinetic energy (TKE) and velocity vector path of dust-air mixture and dust-free air were simulated to understand their effects on coal dust dispersion. The TKE contours and velocity vector paths for dust-free air were uniform and symmetrical due to resistance-free path available. The TKE contours and velocity vector paths for dust-air mixture shows the asymmetrical distribution of contours, due to entrainment of air with dust particles. Vortices were observed in velocity vector paths which gradually diminish on increment of time sequence. These vortices are dead centres where velocity and coal dust particles concentration are both zero.

Published
2020
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6. Prevention and control of spontaneous combustion/fire in coal stockpiles of power plants using firefighting chemicals

Author

Asfar Mobin Khan, Somu Mondal, N.K. Mohalik, Jai Krishna Pandey, S. K. Ray, Debashish Mishra, and R.V.K. Singh

Subjects
Coal stockpile, Waste management, business.industry, Mechanical Engineering, General Chemical Engineering, technology, industry, and agriculture, Energy Engineering and Power Technology, Firefighting, Environmental pollution, respiratory system, Geotechnical Engineering and Engineering Geology, complex mixtures, respiratory tract diseases, Fuel Technology, otorhinolaryngologic diseases, Environmental science, Coal, business, Spontaneous combustion
Abstract

Spontaneous combustion of coal in stockpiles of power plants has a significant problem worldwide which leads to several health hazards, environmental pollution and coal loss. Spontaneous combustion...

Published
2021

7. Methodology in early detection of conveyor belt fire in coal transportation

Author

Debashish Mishra, S. K. Ray, N. K. Varma, N.K. Mohalik, Asfar Mobin Khan, Pradeep K. Singh, and Jai Krishna Pandey

Subjects
Renewable Energy, Sustainability and the Environment, business.industry, 020209 energy, Energy Engineering and Power Technology, Early detection, Thermal power station, Conveyor belt, 02 engineering and technology, Fuel Technology, Electricity generation, 020401 chemical engineering, Nuclear Energy and Engineering, Mining engineering, 0202 electrical engineering, electronic engineering, information engineering, Environmental science, Coal, 0204 chemical engineering, business, Belt conveyor
Abstract

Thermal power units are a major source of power generation in India. Belt conveyor is the leading transportation system in a thermal power plant. Belt conveyor fire in a thermal power plant breaks ...

Published
2020

8. CFD modeling to study the effect of particle size on dispersion in 20l explosion chamber: An overview

Author

S. K. Ray, Asfar Mobin Khan, Debashish Mishra, N.K. Mohalik, Pradeep K. Singh, Jai Krishna Pandey, and N. K. Varma

Subjects
lcsh:TN1-997, Entrainment (hydrodynamics), 0211 other engineering and technologies, Energy Engineering and Power Technology, Astrophysics::Cosmology and Extragalactic Astrophysics, 02 engineering and technology, Computational fluid dynamics, Coal dust, complex mixtures, 020401 chemical engineering, Geochemistry and Petrology, Coal dust explosibility, 0204 chemical engineering, Dispersion (water waves), lcsh:Mining engineering. Metallurgy, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, 021101 geological & geomatics engineering, business.industry, Coal mining, Mechanics, Dispersion, Geotechnical Engineering and Engineering Geology, respiratory tract diseases, Vortex, 20l explosion chamber, Turbulent kinetic energy, Turbulence kinetic energy, Environmental science, Astrophysics::Earth and Planetary Astrophysics, Current (fluid), CFD, business
Abstract

Mine disasters occur predominantly due to methane or coal dust explosion or a combination of both. Among the top ten worst coal mine disasters in India, nine are due to coal dust explosion. The current paper describes a general overview of the parameters causing dispersion leading to coal dust explosion, and computational fluid dynamics (CFD) simulation study to observe the effects of particle size on dispersion in Indian coal mines. Turbulent kinetic energy (TKE) and velocity vector path of dust-air mixture and dust-free air were simulated to understand their effects on coal dust dispersion. The TKE contours and velocity vector paths for dust-free air were uniform and symmetrical due to resistance-free path available. The TKE contours and velocity vector paths for dust-air mixture shows the asymmetrical distribution of contours, due to entrainment of air with dust particles. Vortices were observed in velocity vector paths which gradually diminish on increment of time sequence. These vortices are dead centres where velocity and coal dust particles concentration are both zero.

Published
2020

9. Laboratory Investigation to Assess Spontaneous Combustion/Fire During Extraction of Thick Coal Seam

Author

Debashish Mishra, Asfar Mobin Khan, N.K. Mohalik, N. K. Varma, S. K. Ray, and Nageshwar Sahay

Subjects
0209 industrial biotechnology, animal structures, business.industry, Mechanical Engineering, Metals and Alloys, Coal mining, Mist, Autoignition temperature, 02 engineering and technology, Geotechnical Engineering and Engineering Geology, Mining industry, 020303 mechanical engineering & transports, 020901 industrial engineering & automation, 0203 mechanical engineering, Mining engineering, Proximate analysis, Materials Chemistry, Environmental science, Extraction (military), business, Spontaneous combustion
Abstract

Spontaneous combustion/fire and explosions occurring in the goaf area due to depillaring of thick coal seam (5–8 m) experiences significant loss to the mining industry. This ultimately causes destruction of natural resources and fatal accidents in India. Thus, it is threatening the safety of underground coal mines. This paper includes various laboratory studies to determine the cause of spontaneous combustion/fire during depillaring of panels in thick coal seams. The laboratory investigation comprises of proximate analysis, critical oxidation temperature study, differential scanning calorimetric analysis, fire ladder study, and goaf ignition temperature. The field investigation comprises of hygrometric survey to determine moisture loss and ventilation survey of the working seam to reveal that the goaf of the working panel is highly prone to spontaneous combustion/fire. The results of the above studies will help to develop suitable technique, i.e., partial stowing in goaf areas with the application of water mist spraying to prevent spontaneous combustion/fire during depillaring of thick coal seam. The above studies were carried out during depillaring panels (B2A and B2B) of a thick seam (5.4 m) at Khottadih Colliery, M/s Eastern Coalfields Limited of Raniganj coalfield of India.

Published
2019

10. Application of CFD Techniques to Assess Spontaneous Heating/Fire during Extraction of Thick Coal Seam Using Blasting Gallery (BG) Method

Author

N. K. Varma, N.K. Mohalik, Asfar Mobin Khan, S. K. Ray, Pradeep K. Singh, Ran Vijay Kumar Singh, and Debashish Mishra

Subjects
business.industry, 020209 energy, General Chemical Engineering, Coal mining, General Physics and Astronomy, Energy Engineering and Power Technology, 02 engineering and technology, General Chemistry, Computational fluid dynamics, Key issues, 01 natural sciences, 010305 fluids & plasmas, Spontaneous heating, Fuel Technology, Mining engineering, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Environmental science, Extraction (military), business, Spontaneous combustion, Rock blasting
Abstract

Spontaneous combustion is one of the key issues in the blasting gallery (BG) method of coal mining. Earlier most of the BG panels have been sealed due to the occurrences of spontaneous heating duri...

Published
2019

11. Using CFD to Study Spontaneous Combustion of Coal in Power Plant Stockpile

Author

S. K. Ray, N.K. Mohalik, Asfar Mobin Khan, Debashish Mishra, and Nageshwar Sahay

Subjects
Power station, business.industry, Nuclear engineering, Thermal, Stockpile, Fluent, Environmental science, Coal, Wind direction, business, Spontaneous combustion, Wind speed
Abstract

Spontaneous combustion of coal in stockpiles depends on coal characteristics, stock geometry, ambient atmospheric condition, viz. wind speed, wind direction, and temperature. The study investigates the coal characteristics, using CFD simulation and field investigation to understand the spontaneous combustion phenomena of coal stockpiles; Fluent Ansys 16.2 was used in the study. 3D transient simulation with a time step of 86,400 s was carried out for thirty days. Three different cases, viz. one stockpile, two stockpiles side by side and four stockpiles were studied with ambient temperature at 27 °C, activation energy 4.8 * 107 J/kg mole, wind speed at 4.5 m/s and wind direction along the length of the stockpile. The rise in temperature is noticed at the base of the coal stockpile and the intensity of the temperature was found to be reduced with the increase in stockpile height. Thermal survey of coal stockpiles using infrared gun reveals that the temperature at the base (120–300 °C) is high as compared to the ones at the top (45–60 °C). This high temperature may be due to the stock of coal for a period more than a month. CFD simulation study thus corroborates the field and laboratory investigation data.

Published
2018

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