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Posted by Rick on September 29, 2004 at 17:01:56:
In Reply to: Boiler Feed System Design Pressure posted by A.K.Sinha on September 27, 2004 at 22:25:42:
: We in India, normally design the boiler feed system (from Boier Feed Pump discharge up to boiler economizer inlet) of our thermal power plants for the maximum pressure developed by the boiler feed pumps as per Indian boiler code. The maximum pressure developed by the boiler feed pump is taken corresponding to maximum running speed of the feed pump at its shut off (or minimum recirculation flow) point. This results in excessively high desin pressure for the boiler feed discharge piping and the high pressure feed heaters. We have recently adopted supercritical steam parameters for our plants where the design pressure of feed discharge system works out to around 450 - 500 Kg/Cm2 based on our prevailing practice.
: Please suggest possible measures to bring down the design pressure to lower values.
: Shall be grateful if someone can suggest the prevailing practice in selection of feed design pressure in various countries.
All you need is feedwater pressure about 20 - 25% above drum pressure plus the pressure drop across the economizer.