INTERNATIONAL JOURNAL OF RESEARCH IN AERONAUTICAL AND MECHANICAL ENGINEERING ISSN (ONLINE): 2321-3051 Vol.3 Issue 10, October 2015 Pgs: 9-15 Khub Chand Kushwaha, Bhupendra Koshti 9 PERFORMANCE ANALYSIS AND OFF DESIGN BEHAVIOUR OF FEED WATER HEATER Khub Chand Kushwaha 1 , Bhupendra Koshti 2 1 Khub chand Kushwaha, E-mail kckushwaha08@gmail.com 2 Bhupendra Koshti, E-mail Bhupendrakoshti.bk@gmail.com Department of Mechanical Engineering People`s University, Bhopal, India Abstract A power plant has several utilities and all working in together to meet ever increasing demand of power in efficient way. Off design conditions occur on several occasions in steam power plant. These can occur because of the low load on the power plant and unavailability of some components. Under these conditions the design operating parameters are changed. This paper describes the various conditions which leads feed water heater to work under off design conditions, which changes its performance and effectiveness. This paper also discusses the behavior of feed water heater under these conditions of operation. Keywords: Feed water heater, Steam, off-design conditions, Temperature, Feed water. 1. Introduction 1.1 Feed water heater A Feed-water heater is a power plant component used to pre-heat water delivered to a steam generating boiler. A practical Regeneration process in steam power plants is accomplished by extracting or bleeding, steam from the turbine at various points. This steam, which could have produced more work by expanding further in the turbine, is used to heat the feed water instead. The device where the feed water is heated by regeneration is called Regenerator or a Feed water Heater. A feed water heater is basically a heat exchanger where heat is transferred from the steam to the feed water either by mixing the two streams (open feed water heaters) or without mixing them (closed feed water heaters). 1.2 Open Feed water Heaters An open feed water heater is basically a mixing chamber, where the steam extracted from the turbine mixes with the feed water exiting the pump. Ideally, the mixture leaves the heater as a saturated liquid at the heater pressure. The advantages of open heater are simplicity, lower cost, and high heat transfer capacity. The disadvantage is the necessity of a pump at each heater to handle the large feed water stream. 1.3 Closed Feed water Heaters In closed feed water heater, the heat is transferred from the extracted steam to the feed water without mixing taking place. The feed water flows through the tubes in the heater and extracted steam condenses on the outside of the tubes in the shell. The heat released from the condensation is transferred to the feed water through the walls of the tubes. The condensate (saturated water at the steam extraction pressure), sometimes called the heater-drip, then passes through a trap into the next lower pressure heater. To some extent, this reduces the steam required by that heater. The trap passes only liquid and no vapours. The drip from the lowest pressure