Proceedings of ASME Turbo Expo 2003 Power for Land, Sea, and Air June 16-19, 2003,Atlanta, Georgia USA 2003-GT-38757 INLET FOGGING FOR A 655 MW COMBINED CYCLE POWER PLANT- DESIGN, IMPLEMENTATION AND OPERATING EXPERIENCE Hemant Gajjar Gujarat Paguthan Energy Corporation Pvt. Ltd. Paguthan, India Mustapha Chaker, Ph.D, Ajay Dighe, Cyrus B. Meher-Homji, P.E. Mee Industries Inc, Gas Turbine Division Monrovia, CA, USA. ABSTRACT The design, installation, commissioning and operation of a fogging system for a large 655 MW combined cycle power plant is described. Technical details and practical installation issues are discussed. Special considerations as to how the fogging system could help in the augmentation of power during high temperature and low frequency operation of the gas turbine is discussed. Finally a discussion is made regarding the importance of inlet filtration and the proper selection of blade coatings. NOMENCLATURE DBT Dry bulb temperature, ° C WBT Wet bulb temperature, ° C EOH Equivalent Operating Hours CFD Computational Fluid Dynamics IGV Inlet Guide Vane FOD Foreign Object Damage Lpm Litre per Minute Hz Line Frequency, Hertz INTRODUCTION Gujarat Paguthan Energy Corporation Pvt. Ltd.’s (GPEC) genesis can be traced to the year 1991, when Govt. of India liberalized different sectors of economy and invited the private sector to participate in increasing the power generating capacity of the country. The project took off with laying of the foundation stone on 24 th January1996. The ambitious 655 MW gas based Dual Fuel Combined Cycle Power Plant is located near Bharuch in the State of Gujarat, India. The first gas turbine was commissioned in October 1997, twenty one months after laying the foundation stone. Combined cycle operation commenced in October 1998. GPEC was the first IPP of a power project of this size in India and was the first project in the country to go on stream with Naphtha as a major fuel. GPEC’s plant comprises of : • Three Siemens type V94.2 Gas Turbine Generators each rated at 138 MW. • Three Waste Heat Recovery Steam Generators (HRSG) supplied by Deutsche Babcock producing 275 tonnes/hr • One Siemens Steam Turbine Generator rated at 241 MW. The Gas Turbines are capable of firing Gas and Naphtha independently as well as simultaneously in dual fuel mode. Gas is received by a pipeline from nearby Gandhar Gas fields. Naphtha is received by Rail Wagons at a Railway Siding, stored and then pumped via a 10” diameter 7 km long pipeline to the site storage facilities. Electrical power produced is evacuated through 220 KV and 400 KV switchyards to Gujarat Electricity Board for further distribution. The plant Water supply is derived by drawing water from the Narmada River and pumping it via a 36” diameter 24 km long pipeline to the reservoirs at site. Water is then treated in a pre-treatment plant and Demineralization plant for further use. UNDERLYING NEED FOR GAS TURBINE INLET COOLING The climatic conditions in Gujarat include a very hot summer season where the ambient temperatures can reach temperatures of 45° C. During this period, gas