Power Research

K. H. Arun Kumar ¹, V. Saravanan ², M. Shekhar Kumar ³

Affiliations
1 SRF, Materials Technology Division, Central Power Research Institute, Bengaluru-560080, IN
2 Joint Director, Materials Technology Division, Central Power Research Institute, Bengaluru-560080, IN
3 Additional Director (Retd.), Materials Technology Division, Central Power Research Institute, Bengaluru-560080, IN

Abstract

Two Indonesian coals from different mines were blended with a high ash representative Indian coal obtained from South Eastern Coalfield Limited (SECL) mines at different proportions like 10/90, 20/80, 30/70 and 50/50. These blends were characterized for the qualitative and quantitative parameters based on additive rule. The additive/non-additive behavior of these blend proportions were studied comparing the experimentally obtained value with the calculated values based on additive rule. The results obtained indicate that the quantitative parameters like proximate and ultimate parameters were found to be additive and the qualitative parameters like ash fusion temperature and Hardgrove Grindability Index (HGI) were found to have deviation from the calculated values. Among the two different blends one blend showed additive characteristics on the HGI values while the other one showed non-additive characteristics. The Ash Fusion Temperature (AFT) was found to be non-additive in both the blends.

Keywords

Two Indonesian coals from different mines were blended with a high ash representative Indian coal obtained from South Eastern Coalfield Limited (SECL) mines at different proportions like 10/90, 20/80, 30/70 and 50/50. These blends were characterized for the qualitative and quantitative parameters based on additive rule. The additive/non-additive behavior of these blend proportions were studied comparing the experimentally obtained value with the calculated values based on additive rule. The results obtained indicate that the quantitative parameters like proximate and ultimate parameters were found to be additive and the qualitative parameters like ash fusion temperature and Hardgrove Grindability Index (HGI) were found to have deviation from the calculated values. Among the two different blends one blend showed additive characteristics on the

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R. K. Kumar ¹, M. Janardhana ¹, T. R. Venkatesh ¹, M. Shekhar Kumar ¹, K. H. Arun Kumar ²

Affiliations
1 Central Power Research Institute, Bangalore-560080, India
2 Senior Research Fellow, Central Power Research Institute, Bangalore, IN

Abstract

The Condition Assessment of Generator rotor shaft of typical 108MW plant has been carried out involving the application of advanced Phased Array Ultrasonic Technique (PAUT)to quantify the volumetric nature of the defects in the rotor. This technique involves mapping of the entire rotor volume in different segments and layers using multiple ultrasonic sensors. The imaging of defects in the rotor shaft was carried out in four different diameter sections 558 mm, 610mm, 737 mm and 914 mm. The scanning of entire shaft geometry regions was done following different patches from top to bottom portion of the shaft by PAUT and analysis of individual scanning results for evaluation of crack size, position inside the rotor geometry and orientation. The critical defects identified by this technique with their locations and orientation inside the rotor has been presented. The stress and fatigue life of the shaft under defect free conditions have been carried out by finite element analysis using the commercial code Fe-Safe^TM. The calculation of remaining life of the rotor shaft was carried out based on the principle of fracture mechanics using the code ZENCRACK^TM. The results of the crack growth rate data of critical cracks close to the surface were presented.

Keywords

Hydro Turbine Generator, Phased Array Ultrasonic Inspection, Stress Analysis

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K. H. Arun Kumar ¹, V. Saravanan ², R. K. Kumar ², M. Shekhar Kumar ³

Affiliations
1 SRF, Materials Technology Division, Central Power Research Institute, Bengaluru-560080, IN
2 Joint Director, Materials Technology Division, Central Power Research Institute, Bengaluru-560080, IN
3 Additional Director (Retd.), Materials Technology Division, Central Power Research Institute, Bengaluru-560080, IN

Abstract

The computational fluid dynamics (CFD) assessment was carried out for the combustion of pure Indian coal and the blends of Indian/imported coals at various proportions in a typical 210 M We Indian boiler. The input fuel mass flow rate was calculated in various cases to give the same thermal input to the boiler. The various sub models used for the CFD assessment has been described in the paper. The velocity and temperature profiles of the gas phase, combustion profile of the particles, heat flux distribution to the walls of the boiler and also the thermal efficiency of the boiler were assessed in the present work. It was found that the particle and fluid dynamics play a major role in the heat flux distribution in the boiler. The Indian and imported coal blend proportion of 80/20 showed good thermal efficiency compared to the pure Indian coal and other blend proportions.

Keywords

Blended Coal, CFD, Indian Boiler, Heat Flux Distribution, Pre-mixed Blending

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