IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Comparative study on sorption characteristics of coal seams from Barakar and Raniganj formations of Damodar Valley Basin, India
Get PDFThe methane retention mechanism in coal seams is markedly different from those of conventional gas reservoirs. Methane remains mainly as physically adsorbed molecules on micropore surface. Chemical and petrographic compositions of coal are the measures of maturity and type of organic matter that control the methane sorption characteristics of the coal. 99% of Indian coal occurrences are contributed by lower Gondwana sequences housed in two major geologic formations, younger Raniganj and older Barakar. The Raniganj Formation is best exposed in Raniganj Sub-basin and Barakar Formation is best exposed in Jharia Sub-basin of Damodar Valley. Present work attempts a systematic investigation on comparative account of methane sorption characteristics of coals from Raniganj Formation of Raniganj Sub-basin and Barakar Formations of Jharia Sub-basin in relation to their chemical composition and petrographic makeup. Chemical analyses shows that moisture, ash, volatile matter and fixed carbon varies between 2.5 and 4.6%, 10.0–27.2%, 38.8–40.2% (dmmf) and 59.8–61.2% (dmmf),
respectively for Raniganj coals and, 0.5–1.1%, 16.7–32.9%, 20.7–22.0% (dmmf) and 78.0–79.3% (dmmf), respectively for Barakar coals. Carbon content is distinct for the suites of coal, 79.2–85.4% and 85.6–92.0% for Raniganj and Barakar coals, respectively. The vitrinite reflectance for the Raniganj coals ranges 0.53–0.72% and the Barakar coals ranges 1.09–1.23%. Based on the chemical composition and vitrinite reflectance value Raniganj coals belongs to high volatile bituminous type, whereas Barakar coals belongs to high to medium volatile bituminous type. Such variation in composition and maturity is mainly attributed to the variation in precursor organic matter as well as the basinal and thermal history of the sub-basins under consideration. H/C atomic ratio of the Raniganj and Barakar coals varies between 0.65 and 0.80 and 0.51–0.72 and O/C atomic ratio varies between 0.05 and 0.13 and 0.01–0.07, respectively. Coals of both the Raniganj and Barakar formations are mostly of kerogen Type-III with Raniganj coals falling in wet gas maturity stage approaching early-thermogenic methane generation whereas Barakar coals falling in condensate gas stage approaching peakthermogenic methane generation. The Langmuir volume ranges from 9.3–21.8 cc/g (daf) for Raniganj coals and 21.1–29.1 cc/g (daf) for Barakar coals. Sorption capacity for the set of coals shows a strong rank dependency and increase with corresponding increase in rank down the stratigraphic column. Methane sorption capacity shows positive relationship with carbon content and vitrinite reflectance, and negative relationship with moisture content, ash and volatile matter. Moisture effect is more prominent in low rank Raniganj coals. The adsorption capacity shows a strong positive relation with vitrinite content and a moderate negative relation with inertinite content for both the Raniganj and Barakar coals, which may be attributed to dominancy of micropores in vitrinites with rank enhancement. The multiple regression analysis shows that the moisture is the main predictor of the VL, and the interaction of moisture with ash and reflectance mainly control the sorption capacity. A predictive model equation is developed for determination of sorption for Damodar basin coals from carbon, ash and moisture data
IMPACT OF PLANT NUTRIENTS ON PREDICTION OF WHEAT CROP YIELD FROM POND ASH AMENDED FIELD BY ARTIFICIAL NEURAL NETWORKS
No full textIn India presently, 145 existing Thermal Power Plants (TPPs) contribute about 70% of the total energy requirement and produce approximately 184 million metric tons of fly ash per year, which is projected to exceed 440 million metric tons per annum by 2030. This quantity of fly ash generated poses significant environmental problems, besides occupying large areas of land for its dumping, requiring appropriate measures for its safe disposal and gainful utilization on sustainable basis. Based on the field demonstration work carried out on the bulk utilization of pond ash in agriculture and forestry sectors under different agro-climatic conditions and soil types for the last two decades, it has been well established that pond ash has significant potential for utilization as liming agent, soil conditioner, source of plant nutrients and also for boosting the growth and yield of a variety of crops. Some field scale studies carried out especially in the waste/alkaline lands of State Agriculture Research Farm and farmers’ fields are discussed in the present paper for the development of artificial neural network (ANN) for the correlation of crop yields and plant nutrients.
As such, the influence of major plant nutrients viz. N, P, K, Ca, Mg and S on the yield of wheat crops cultivated in different soil types and agro-climatic conditions is discussed. Furthermore, an attempt has also been made to develop a three-layer feed-forward artificial neural network (ANN) model. Satisfactorily enough, it has been found that the predictions of the developed ANN model are in quite good qualitative and quantitative agreement with the experimental results
Insight into emerging applications of forward osmosis systems
No full textThe advent of Forward Osmosis (FO) has ushered in a new revolution in the field of membrane technology. Besides the oft-studied application of water purification, FO has opened up new frontiers of research in diverse fields. All of them are potentially sustainable technology solutions characterized by a high degree of process intensification. It is interesting to imagine different avenues where the potent combination of membrane technology and osmotic gradient can be used. This brief review evaluates four such emerging applications of FO; viz: Membrane Crystallization, Osmotic Pumps, Energy Production, and Membrane Evaporation which will be considered as the most important in the near future. All four aforesaid applications were critically reviewed with respect to the principle of operation, process design fundamentals, cost distribution, tangible benefits over conventional alternatives and commercial ventures around the world. Comparative assessments of transport flux, yield, configuration, and membrane module was carried out. Several issues relating to performance, hydrodynamics and scale up designs were analyzed with special emphasis on concentration polarization, flux decline, nature of the membrane
Understanding Coal Combustion Residues Leaching Chemistry Under Disposal Environment
No full textThe present study is focused on leaching characteristics of coal combustion residues under the disposal environment. The coal combustion residues collected from a thermal power station of Eastern India were used for the study purpose. Leaching study using open column percolation experiment were carried out for almost three years to understand the long-term effects of disposal of such solid wastes in the disposal environment. Potentiometric parameters, like pH, conductivity and total dissolved solids (TDS) of the samples were studied and was found within the permissible limits for effluent discharge in the inland surface water bodies and on land for irrigation (IS:2490). The leachates pH reflected that coal combustion residues (CCRs) are slighltly acidic to alkaline but overall on the long-term basis, these are alkaline in nature. The leachates were also analyzed for 23 elements. The study revealed the elements, like Ca, Mg, Na and K were at a higher concentration as compared to other elements. These elements were found to be leaching throughout the study period although their concentrations reduced considerably with time. The most volatile elements, like B, Hg, Se and others, such as Cr, Ni, Cd, Al, Ag, As, Ba, V, Sb, Mo were reported at BDL level. Elements, like Fe, Mn, Ci and Zn showed intermittent leaching. These were found to leach at significant concentration levels for some time but found to be absent on a long-term basis. Thus, the leaching study conducted on five samples of Burnpur Thermal station clearly shows that coal combustion residue is safe with respect to trace and/or heavy metals leaching in the disposal environment when used as a fill material in bulk
Slow loading yielding prop for underground mines – an invention
No full textIn general, underground mines/tunnels/roadways are supported especially in India, by using wooden cogs/props as support in addition to the massive use of roof bolting. But as wood is becoming scarce, there is need for suitable alternative supports to replace timbers in mines. Keeping in mind the Indian mining condition the support should be of greater longevity. Light enough for easy portability and requiring less maintenance. Further, it should have facilities for height variation, sufficient yielding, continuous load monitoring and releasing remotely as the coal seam thickness varies widely in Indian mines. Then, the support material must be easily available and should have ease in operation by even an unskilled worker. Finally, the device must be economically viable for Indian mines, which is thriving for its longer life and should provide safety for miners. In this direction several efforts have been made to design such slow loading yielding props to meet all these requirements. After numerous attempts such innovative prop consisting of multiple disc springs has been designed and developed at CSIR-CIMFR of which the details description has been discussed in this paper
Laboratory Investigation to Assess Spontaneous Combustion/Fire During Extraction of Thick Coal Seam
No full textSpontaneous 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
Roof sagging limit in an early warning system for safe coal pillar extraction
No full textField studies have found that, generally, a roof fall takes place after certain amount of roof strata sagging. Recent applications of auto warning tell-tale (AWTT) instrument as an early warning system at different depillaring panels found it to be simple, economical and efficient during the coal pillar extraction (called depillaring). AWTT is able to watch the set value of roof sagging continuously in time. However, the application of AWTT experienced two practical issues: (i) fixing roof sagging warning value before the fall of overlying strata and (ii) deciding horizon above which its anchorage point of AWTT needs to be installed. Different field experiences noticed that an anchorage horizon at 10 m depth from the ceiling of a gallery works satisfactorily for goaf edge. But fixation of the roof sagging warning value, before the fall of overlying strata, is found to be complex. Generally, the warning value for a given site conditions is determined by extensive field monitoring and correlation of the roof sagging value at the goaf edge with corresponding roof falls. Field studies found that modulus of elasticity and thicknesses of immediate roof are important parameters in deciding the warning value of the roof sagging. These studies also indicated that the variation in size of the left-out ribs and goaf span influence the warning value. These observed facts about the warning value for an AWTT are studied in laboratory using a numerical modelling approach in FLAC3D. The results obtained through developed simulated models are found to be in close agreement with those of the field studies. Attempts are also made to quantify the influence of above-mentioned parameters over the warning value through collated results of different studied models. The obtained results of field and laboratory investigations are presented and discussed in this paper for strata control in a depillaring panel
Detection and Analysis of Coal Fire in Jharia Coalfield (JCF) Using Landsat Remote Sensing Data
No full textCoal fires are common and serious problem in most of the coal producing countries of the world. In India, Jharia Coalfield (JCF) has one of the dense surface–subsurface coal fires in the world. The paper presents a case study of fire mapping and its propagation dynamics of JCF during 2001 to 2016 using Landsat data at consecutive 5 year interval. The study reveals that there are three distinct zones of fire in JCF viz., Eastern zone (Rajapur, Lodna, Kustore, Eastern Jharia, Bastacola, Chasnala (IISCO) and Bhowrah), Western Zone (Barora area of Shatabdi, Muraidih open cast mines) and Central zone (Kustor, Tisra, Bhulanbarari, Gonudih Khas Kusunda Colliery (GKKC), Sijua and Modidih colliery). The maximum temperature observed from Landsat data in JCF for years 2001, 2006, 2011 and 2016 is 50 °C, 53 °C, 57.5 °C and 56.5 °C, respectively. In the year 2016, the eastern part of JCF was relatively more affected by coal fire than the western part, showing prevalence of major surface and subsurface coal fire. The same trend was maintained from 2001 to 2016. The total fire area is 8.85 km2, 9.34 km2, 9.78 km2, 8.42 km2 in the years 2001, 2006, 2011 and 2016, respectively. The total fire area is reduced by 0.43 km2 (from 8.85 to 8.42 km2) from 2001 to 2016
Hydrocarbon-generation potential and thermal-maturity of few Indian coals: inferences from organo-petrography and Rock-Eval
No full textIn this work, hydrocarbon-generation potential and thermal-maturity of few Indian coals from two Indian basins have been studied. Samples from Jharia basin were observed to be more mature showing higher vitrinite reflectance, Rock-Eval Tmax, and lower volatile matter (VM) yield, hydrogen index (HI). The baked-coal (Jhama) showed least HI, VM, and highest Tmax, indicating the thermal-influence of igneous intrusions. Liptinite concentration was observed to be directly controlled by the maturity indices. The most-mature coal, beyond ‘third coalification jump’ was marked by absence of liptinites, while the least-mature sample, placed near ‘first coalification jump’ was marked by highest liptinite content, S1 and S2. All these indicate the influence of maturity on hydrocarbon-generation and organic-composition of coals. Strangely, the petrographically determined original HI (HIO) was observed to be lower than present-day HI values. Negative fraction-of-conversion (f) was observed in the coal samples, erroneously implying that no kerogen-conversion or hydrocarbon-generation has taken place from the samples. This could possibly be caused due to presence of sub-microscopic hydrogen-rich organic-materials, not identifiable under microscope
