Abstract: This paper introduces the optimum selection on pipe diameter of feed water system for Zhejiang Guohua Ninghai Power Plant PhaseⅡ 2×1000 MW Extension Project. After advised calculation and analysis, comparing deferent schemes of pipe size of feed water system technically and economically, the optimized pipe specifications have been selected for low-pressure pipe, high-pressure pipe and recirculation pipe in the feed water system.

Key words: feed water system, optimum of pipe diameter, investment saving