夏季工况直接空冷系统最佳真空特性的研究  

Characteristic Study on Optimal Vacuum of a Direct Air-cooling System Under Summer Conditions

作　　者：李晓恩[1] 王宁玲[1] 冯澎湃 杨志平[1] 

机构地区：[1]华北电力大学国家火力发电工程技术研究中心,北京102206

出　　处：《动力工程学报》2016年第11期927-933,共7页Journal of Chinese Society of Power Engineering

基　　金：国家重点基础研究发展计划资助项目(973计划)(2015CB251505);国家科技支撑计划资助项目(2014BAA06B02);国家自然科学基金资助项目(U1261210;51306050);中央高校基本科研业务费专项资金资助项目(2015MS43;2015XS81;2014XS19;2014XS13)

摘　　要：以某660MW超临界直接空冷机组为研究对象,基于机组夏季工况下实际运行数据,建立了汽轮机变工况模型与空冷系统变工况模型,并分别利用电厂空冷系统常干时性能曲线以及电厂原热力特性计算说明书验证了这2个模型的计算准确性.分析了不同边界条件下(包括空气温度、凝汽器的换热环境、负荷、风机转速等)凝汽器最佳真空的选取.结果表明:夏季工况下,当负荷较高时,风机应始终保持在超频运行,以维持空冷系统的背压,保证运行安全性;当负荷较低时,在固定凝汽器蒸汽质量流量下,随着冷却空气量的增加,机组出力增加量与风机耗功增加量的差值有最大值.运行时应首先考虑如何合理设置运行参数以得到较高经济性.Taking a 660 MW supercritical unit as an object of study, two off-design models were set up re- spectively for the steam turbine and air-cooling system based on its operation data obtained under summer conditions, of which their calculation accuracy was subsequently verified with the performance curves for constant dryness and the data in original calculation specifications. Moreover, the way how to determine the optimal vacuum of the condenser was analyzed under different boundary conditions, including the air temperature, the heat exchange of condenser, the load and the fan speed, etc. Results show that under summer conditions, when the load is relatively high, an overclocked operation should be kept for the fan, so as to guarantee a safe backpressure and operation for the cooling system, whereas when the load is rela- tively low, in case of a fixed extraction flow, the pursuit of high operation economy becomes important, since the difference between the rise of unit output and the rise of fan power consumption has a maximum value with the increase of cooling air flow.

关 键 词：空冷凝汽器 最佳真空 变工况模型 夏季工况 

分 类 号：TM621[电气工程—电力系统及自动化]