IR@CIMFR - Central Institute of Mining and Fuel Research (CSIR)
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Coal combustion analysis using Rock-Eval: importance of S4-Tpeak
No full textThe Rock-Eval technique has been conventionally used for source-rock analysis. In this work we document the importance of Rock-Eval S4 oxidation graphics and S4-Tpeak as indicators for coal reactivity and thermal maturity. Two non-coking coals (lower maturity), one coking coal (higher maturity), and one jhama (intrusion-induced metamorphosed coal), were collected and studied in terms of their reactivity and combustion properties. Our results indicate that Rock-Eval S4-Tpeak can be convincingly used to decipher the thermal maturity level of a coal sample. The two non-coking coals owing to their higher reactivity and corresponding lower activation energies, combusted at lower temperatures, almost entirely below 650 °C, and showed lower Rock-Eval S4-Tpeak. The coking coal sample on the other hand due to its higher thermal maturity level and lower reactivity, combusted at higher temperature, showing higher S4-Tpeak. While the S2 Tmax showed higher maturity for the coking coal than the jhama, the S4 oxidation graphics and S4-Tpeak clearly revealed higher thermal maturity of the jhama relative to the other samples. With increasing sample weights, the S4CO2 curves were observed to be broader, and consequently the S4-Tpeak was observed to be higher and erroneous, the errors being more for the more-mature coking coal and jhama. With lowering sample weights, the curves became tighter and the S4-Tpeak became lower and more precise. Parameters calculated using TG-DTG-DSC were observed to complement the data from Rock-Eval oxidation-stage, and revealed higher maturity, less reactivity, higher temperatures of ignition and burn out for the jhama, followed by the coking coal. Our results also indicate the suitability of applying Rock-Eval for combustion-profiling of coals, beyond source-rock characterization and CBM reservoir analysis
Assessment of Near Surface by 2D Electrical Resistivity Tomography over Hard Rock Terrain: A Case Study
No full textThe existence of type of subsurface soil at any location primarily depends on origin of the host rock. There are several engineering applications of soil in global scenario and geophysical methods paly a significant role in it such as status investigation of subsurface soil conditions. The present study encompasses mapping of soil horizon over hard rock terrain being conducted in the premises of Central institute of Mining and Fuel Research (CIMFR) campus, Dhanbad, Jharkhand, India. Electrical Resistivity tomography (ERT) Survey has been carried out for investigation adopting Wenner-Schlumberger and Dipole-Dipole arrays.
The combination of these two configurations assists in developing confident interpretation. Smoothness constrained least-square technique has been used in analysis using RES2DINV software. It is observed that the soil horizon has been identified by its relatively low resistivity anomaly. The encouraging inferences reaped the efficacy of ERT tool in application of soil investigation
Evaluation of Groundwater Quality for Suitability of Irrigation Purposes: A Case Study in the Udham Singh Nagar, Uttarakhand
No full textIn the present study, the groundwater quality for suitability in agriculture from Udham Singh Nagar district, Uttarakhand, has been evaluated. A total of 50 groundwater samples have been collected and analysed for pH, EC, TH, HCO3−, CO32−, Cl−, SO42−, NO3–, Ca2+, Mg2+, Na+ and K+. To assess the groundwater quality for irrigation purpose, parameters like sodium adsorption ratio (SAR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), magnesium hazards (MHs), permeability index (PI), and chloroalkaline index (CAI) values have been calculated. In USSL diagram, most of the groundwater samples fall in the C2S1 category and were safe for irrigation purpose. Only seven groundwater samples fall in the C3S1 category, indicating medium to high salinity which is safe for irrigation purpose for all types of soils but with limited care of exchangeable sodium. On the basis of RSC, all groundwater samples were observed to be suitable for irrigation purpose. Piper diagram indicated that 50% of the groundwater samples belonged to the Mg2+-Ca2+-HCO3− type and 48% was classified as the Ca2+-Mg2+-Cl− type. Durov diagram suggested possibilities of ion mixing and simple dissolution of ions from polluted soil
Cleaning Potentialities of High - Ash Non - Coking Coal of SCCL Coalfields through Washability Investigations
No full textThe Indian coals contain high ash content mainly due to its typical origin and formation. The State of Andhra Pradesh is having huge reserves of non coking coal but they are high ash content and needs to be beneficiated before using it for different end uses. This article describes the washability characteristics of a typical high ash non coking coal from Singareni Collieries Company Limited, area aiming at 34% ash level in the clean coal for power generation. Conventional float-and-sink testing was used to determine the yield of clean coal. A suitable flow scheme for beneficiation of the non-coking coal was suggeste
Utilization of Coal and Biomass Ash
No full textSustainable utilization of the ash generated from the combustion of coal or biomass is a big challenge for the power industry. Huge quantities of ash are generated and, in general, they are disposed-off in ash ponds. However, recent regulatory requirements demand 100% utilization of ash. So many new areas of ash utilization are being explored by the researchers and ash managers. Bulk utilization sectors are cement industry, construction, bricks, landfill, mine back filling, and soil amendment for growing plants. Efforts to enhance the use in value-added low-volume sectors like fertilizer, cenosphere, catalyst support, zeolites, aerogels, and so on are continuously evolving. The heterogeneity of the ash properties is one of the main challenges for advocating a generalized utilization pattern of the ash. Biomass has some typical properties that limit its use for some sectors. However, beneficiation of both coal and biomass ash and use of other additives could improve the suitability of the ashes to multifarious uses
Damage threat to sensitive structures of a thermal power plant from hard rock blasting operations in track hopper area: A case study
No full textThe article deals with the development of controlled blast design patterns and methodologies for excavation of hard rock for foundation work of a track hopper in a running thermal power plant in close proximity of many sensitive structures. Test blasts were conducted with different blast geometries and charge loading patterns at selected locations. The results of the test blasts were analysed to evolve safe controlled blast design patterns and methodologies for completing the total excavation work. The threshold value of vibration for the safety of various structures/foundations present has been taken as 25 mm/s based on the dominant frequency content as well as guidelines from the regulatory authority. The dominant frequency content of the ground vibration waves was in the range of 10–40 Hz. Controlled blast design parameters, namely maximum explosive per delay, size of the blasts and blast geometry were formulated based on established ground vibration predictor equation and nearness of structures concerned from the blasting point. Two blasting zones were classified for safe excavation work. For the first zone within 20 m from the structures, controlled blasting using 32-mm diameter blast holes with small blast geometry was suggested, whereas for the second zone beyond 20 m, controlled blasting with 100-mm diameter holes with lesser hole depth and limited number of holes was suggested. The whole excavation work in the track hopper area was completed safely without causing any damage to the nearby sensitive structures of the running thermal power plant
Human Health Risk Assessment Due to Metals in Cow's Milk From Singhbhum Copper and Iron Mining Areas, India
No full textThe concentration of Al, As, Ba, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn were determined in the milk collected from the locally rearing cows from the vicinity of copper mining areas of East Singhbhum and iron mining areas of West Singhbhum using inductively coupled plasma-mass spectrometry for a risk assessment and source apportionment study. Principal component analysis suggested both natural and anthropogenic activities as causative sources of metals in the milk. The hazard indices ranged from 0.26 to 0.89 with a mean of 0.56 in the iron mining areas and 0.29-1.89 with a mean of 1.17 in the copper mining areas due to ingestion of milk, which indicated that the risk is negligible in the iron mining areas while there is an appreciable risk to the health of consumers of milk in the copper mining areas
CFD modeling to study the effect of particle size on dispersion in 20l explosion chamber: An overview
No full textMine 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
