凝结水泵的最佳调节方案分析

为研究变频调速技术在200MW凝汽机组凝结水泵调节中应用的节能效果，分别按照由机组承担的负荷、除氧器运行方式及调节形式形成的6个方案进行计算分析。首先，由管路性能曲线和泵特性曲线取得各工况点的流量、扬程和效率，椐此并利用电动机和变频器的效率等获得凝结水泵消耗的电功率和全年运行时间段的耗电量，最后可有进行方案比较分析的年费用值。在各方案中采用变频调速方式相对于节流调节方式耗电量要小；调峰负荷下的各种方案要比对应基本负荷的情况耗电量和年费用小；调峰负荷时除氧器滑压运行方式下的变频调速方案是最经济方案。结果表明，虽然凝结水泵的变速调节方式初投资较高，但在各运行工况特别是启停和非设计工况节能潜力巨大，可延长设备寿命，有较强的经济效益，推广应用性强。图4表1参6

Optimized Governing of Condensate Pumps

For the purpose of studying the energy-saving effect of frequency conversion-based speed governing, applied to the condensate pump of a 200MW turbine set, 6 combinations of different turbine loads, deaerators, operation modes and ways of governing are calculated and analyzed. First of all, the flow, the pumping head and efficiency are found with the help of pipeline performance curves and pump characteristics. Then the power consumption rate and the total annual consumption are also obtained with given motor and converter efficiency. At last, annual expenditure of every version can be calculated. Frequency conversion-based speed governing involves less power consumption than by throttling . The power consumption and annual expenditure of every version calculated for cycling duty is smaller than for base load operation. Therefore, the optimal version for cycling duty is speed governing by frequency conversion with variable deaerator pressure. Results show that both efficiency and reliability of frequency conversion-based speed governing are both high. Though primary investment for condensate pumps with frequency conversion control is high,the energy saving potential is remarkable during stop and starting as well as at off-design operation modes, while being beneficial for the equipment's life extension. Because of its practicability and economy this version can readily be popularized. Figs 4, table 1 and refs 6.