Meeta Sharma

Investigations for performance enhancement of dual pressure HRSG in gas/steam combined cycle power plants

ABSTRACT A heat recovery steam generator (HRSG) is the vital equipment in a gas/steam combined cycle power plant (CCPP) which plays an important role in enhancing the overall performance of the plant. An HRSG is designed on the basis of the size of the gas and steam turbines used in the power plant. Therefore, the HRSG directly affects the performance of the CCPP and its optimisation based on physical design can improve the plant performance. In the present study, the plant data of the CCPP of NTPC Ltd. at Auraiya (U.P.), India, has been considered for study. A segmented finned model has been chosen as it is the preferred arrangement [Ganapathy, V. 2003. Industrial Boiler and Heat Recovery Steam Generator Design, Application and Calculation. New York: Marcel Dekker Inc.] and thermodynamic investigations have been carried out upon a dual pressure HRSG in a gas/steam CCPP from the perspective of maximum heat recovery and minimum pressure loss. The performance investigations of varying physical parameters of a dual pressure HRSG with segmented fins are useful for CCPP designers and for all those who are engaged in the area of heat recovery.

Thermodynamic Evaluation of WHRB for it's Optimum performance in Combined Cycle Power Plants

Combined cycle power plants are being extensively used in view of their capability of offering high specific power output and thermal efficiency for same fuel consumption compared to other thermal power plants. Therefore, the studies for optimization of different systems in combined cycle power plant are of great significance. Waste heat recovery boiler (WHRB) being the interface between the topping cycle and bottoming cycle becomes one of the critical components. Present study is undertaken for thermodynamic analysis of waste heat recovery boiler for design change from spiral fin type to segmented fin type in 663 MW capacity gas/steam combined cycle power plant. Results obtained for combined cycle power plant with segmented fin type WHRB have been compared with the actual plant data of combined cycle power plant with spiral fin type WHRB. The conclusions presented in the study are useful for power plant designers.

Improving Assembly Line Efficiency and Output Using Assembly Line Balancing and Reducing Non-Value-Added Activities

Assembly line balancing (line balancing) is a very important tool in today’s competitive environment, as companies need to increase their output without compromising with the quality. Line balancing helps in getting desirable output by equally distributing the work contents at the work stations of an assembly line. Also, removing some non-value-added activities can help in saving time, thus indirectly contributing to efficiency. This paper presents the case study of Wire Harness Company (Delphi Automotive Systems) where the efficiency and output of the assembly line have been improved using assembly line balancing techniques. Here the cycle time at various stations has been balanced so as to get the desired results. Also, some non-value-added activities have been removed to contribute to efficiency.

Parametric analysis of solar energy conversion system using parabolic concentrator and thermopile

The present work aims at improving the design of an energy conversion system operating on solar radiation harvesting and converting it into electricity with the help of thermopiles. Here, the major focus is upon the design parameters and overall performance enhancement of the proposed energy conversion systems. The system consists of a parabolic concentrator to focus all the incident radiations available on the aluminium box containing thermopiles. A mathematical model is proposed for this system and different ways of minimising various possible heat losses are discussed. Furthermore, by maximising the heat flux in a thermoelectric generator, arrangement of the integrated system is analysed. The results obtained for the concentrator, thermoelectric generator and overall system efficiencies at varying energy losses and found that as the losses are decreased, efficiencies increased. At the losses around 40% of the total energy received, an overall efficiency as high as 12% with a considerably less bulky system.

Exergo-economic study of a dual-pressure HRSG in gas/steam combined cycle plants

ABSTRACT Combined power plants are among the most attractive options to optimally utilise conventional fuel energy with respect to energy conversion and the environment. In the present study, a dual-pressure heat recovery steam generator (HRSG) used in a gas/steam combined cycle power plant is investigated. This paper presents exergy and economic analysis of a dual-pressure HRSG. The parameters used for the investigation of the exergo-economic study are pinch point, fuel price, cost of exergy losses, gas turbine inlet temperature and cycle pressure ratio. A parametric study shows that the considered parameters have a huge impact on the total annual cost per unit exergy of steam produced in the HRSG. It is seen that best exergo-economic conditions are obtained at the pinch point value of 10 K to get the total annual cost per unit exergy of steam produced to be the minimum.