Informatics Publishing Limited

J. S. Rao ¹, N. V. S. Ramani ¹, H. J. Pant ², D. N. Reddy ³

Affiliations
1 Corporate R&D Divn, Bharat Heavy Electrical Limited, Vikasnagar, Hyderabad, IN
2 Isotope Applications Division, Bhabha Atomic Research Centre, Mumbai, IN
3 Ex Vice Chancellor, Jawaharlal Nehru Technological University, Hyderabad, IN

Abstract

A pressurized fluidized bed gasifier (PFBG) system of an integrated coal gasification and combined cycle (ICGCC) plant is designed to behave as a well-mixed flow system for coal; and any deviation from the well-mixed flow condition will deteriorate the performance and efficiency of the gasification system. This paper describes a radiotracer investigation carried out to measure RTDs of coal particles in a pilot-scale PFBG with objectives to determine mean residence time (MRT) of coal/ash particles in the gasifier and estimate degree of mixing at different operating and process conditions. Lanthanum-140 labeled coal (100 gm) was used as a radiotracer. The tracer was instantaneously injected into the coal feed line and monitored at ash and gas outlets of the gasifier using collimated scintillation detectors. The measured RTD was used to determine mean residence time (MRT) of coal particles within the system and simulated using fractional tank-in-series model. The results of simulation indicated that the system behaved as a well-mixed system with undesired bypassing of a small fraction coal particle from the system. The results of the study were used to improve the design of the gasifier and optimize the system.

Keywords

Pressurized Fluidized Bed Gasifier, Residence Time Distribution, Radiotracer, Lanthanum-140, Tanks-in-series Model, Bypassing

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J. S. Rao ¹, G. N. Hegde ¹, B. K. Bhaumik ¹

Affiliations
1 AMD Complex, Khasmahal, Eastern Region, Jamshedpur - 831 002, IN

Abstract

Factor analysis of multi-element data for Dhanjori conglomerates of Singhbhum district, Bihar, in eastern India reveals three factors accounting for about 57% of the total information contained in the data. Factors 1 and 2 are associated with radioactive elements. They also indicate that the provenance is a mixed felsic and mafic terrain, and that the minor and accessory constituents of these rocks are concentrated in the conglomentes. These two factors appear to result from the same sedimentological process. The Factor-3 results from the V-A1 diadochy. Factor-1 which is seen to be associated with both zircon and radioelements does not contain Pb. Pb is relegated to the Factor-2.

Keywords

Factor Analysis, Geochemistry, Uranium, Quartz Pebble Conglomerate, Dhanjori Basin, Bihar, Eastern India.

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A. Chaki ¹, D. Bhattacharya ², J. S. Rao ³, A. K. Chaturvedi ³, A. K. Bagchi ³

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy Bangalore - 560 072, IN
2 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy NewDelhi - 110 066, IN
3 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy Hyderabad 500 016, IN

Abstract

Rb-Sr isotopic data for the Tamparkola granite, northwest of Bonaigarh, and Bamra granite, southeast of Barnra, Sundergarh district, Orissa have yielded similar ages of 2746&#177144 Ma and 2738±28 Ma, respectively. Small granite exposures intruding the Iron Ore Group in the southern part of Tamparkola granite, have also indicated similar Whole Rock Rb-Sr age of 2867&#17786 Ma. These may be correlated with the Bonai granite. Significant crustal component was involved in the generation of these granites, as indicated by high initial Sr ratio, and their emplacement probably marks a major terminal cratonisation event in northwestern part of the Singhbhum-North Orissa Craton.

Ths study does not support the view that the Tamparkola Granite is equivalent to the Itrna/Ekma granites that are intrusive into the Gangpur Group. These age results call for a revision of the stratigraphy of the Bonai-Gangpur tract, in that the Darjing Group unconformably overlies both the Bonai granite and Tamparkola granite, with the Mesoproterozoic Kunjar sedimentary sequence representing the youngest of the regional succession.

Keywords

Rb-Sr isotopics, granites, stratigraphy, Kunjar basin, Darjing Group, Gangpur Group, Sundergarh District, Orissa.

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A. Panneerselvam ¹, J. S. Rao ², A. Chaki ¹, A. K. Bagchi ²

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Bangalore - 560 072, IN
2 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad - 500 016, IN

Abstract

Uranium mineralisation has been discovered recently in quartzites near village Kuladera, 15 km ESE of Bamra, Sambalpur district, Orissa. The radioactive quartzites are occurring at the base of the metasedimentary sequence, which is unconformably resting over the unclassified granitoiddgneisses of late Archaean age. Two mineralized quartzite bands, separated by a basic body of epidioritelamphibolite, have been identified. The samples radiometrically assayed 0.018 to 0.15% U₃O₈ and are free of thorium. The uranium minerals identified are uraninite, gummite, torbernite and U-Ti complex. The other mineral phases contributing to the radioactivity are metamict allanite, zircon, anatase, limonite, epidote and goethite. The samples also analysed higher concentration of Ti, V, Cr, Zr, Cu, Mo, Pb and Ag. As the uranium mineralisation is at the unconformity between the Proterozoic metasediments and basement crystallines, it opens up a new and promising potential target area in this part of Orissa for uranium exploration.

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