电站余热利用方案的热力学对比分析  

Thermodynamic comparison of waste-heat utilization schemes in power plants

作　　者：宋晓娜[1] 韩宇[2] 张晨旭[2] 徐钢[2] 刘超[2] 杨勇平[2] 

机构地区：[1]北京信息科技大学机电实习中心,北京100192 [2]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：《热力发电》2014年第8期14-18,共5页Thermal Power Generation

基　　金：北京高等学校青年英才计划项目(NO.71A1411127);国家自然科学基金项目(U1261210);国家重点基础研究发展计划项目(973计划)(2011CB710706)

摘　　要：我国电站普遍存在燃煤耗量高,机组效率低的问题,在锅炉尾部烟道增设余热利用系统是解决此问题的重要手段之一。以国内某超超临界1 000MW机组为例,对电站传统余热利用方案和新型并联余热利用方案进行了热力计算及火用分析对比。结果表明:新型并联余热利用方案可使机组供电煤耗降低值增至传统余热利用方案的2倍,空气加热部分火用损降低5.4MW,使空气预热器火用效率由78.3%提高至85.0%;机组热功转换效率显著提高,节能效果显著。Large coal consumption and low unit efficiency are common issues in China＇s current power plants.Generally,adding waste-heat utilization system in rear gas flue of boilers is an important way to solve this problem.Taking a domestic ultra supercritical 1 000 MW unit as the example,thermodynamic calculation and exergy analysis of the conventional waste heat utilization scheme and the new parallel connection waste heat utilization scheme were conducted.Moreover,comprehensive comparison between the above two schemes was carried out.The results show that,compared with the conventional waste heat utilization scheme,the net coal consumption rate reduction of the new parallel connection waste heat utilization scheme rose from 1.80g/（kW·h）to 3.62g/（kW·h）,reducing exergy loss of 5.4MW during the air preheating,improving the exergy efficiency of the air preheater from 78.3%to 85.0%.To sum up,the new parallel connection waste heat utilization scheme dramatically increased the unit efficiency and had great energy-saving effect.

关 键 词：超超临界 1 000MW机组 烟气余热利用 热力计算 火用分析 高温烟水换热器 低温烟水换热器 

分 类 号：TK219[动力工程及工程热物理—动力机械及工程]