超超临界锅炉的汽温偏差探析  

Research on the Steam Temperature Deviation in the Ultra-supercritical Boilers

作　　者：樊泉桂[1] 樊晋元[1] 

机构地区：[1]华北电力大学能源与动力工程学院,河北保定071003

出　　处：《锅炉技术》2010年第2期1-4,17,共5页Boiler Technology

摘　　要：根据实际运行数据研究了超超临界锅炉的汽温偏差变化规律和影响汽温偏差的特殊因素。指出特殊因素为:在湿态向干态转变和跨越临界点时工质热物理特性变化大;过热器系统的蒸汽流程延长、汽温偏差的累积效应增大;水煤比变化等;必须注意单侧减温水量过大,将加剧流量偏差,甚至引发临界流,进而扩大汽温偏差。实例反映的汽温偏差变化趋势为:超临界锅炉在低负荷运行阶段汽温偏差最大;在临界压力附近,汽温偏差被放大;在90%负荷以上过热器出口汽温偏差可以控制在低于5℃的设计值。对于制造、安装和焊接等工艺质量引起的超温爆管或流量偏差更要高度重视。The variation law of steam temperature deviation and the special factors affecting steam temperature deviation have been analyzed based on the practical operation data in the ultra-supercritical boilers. It is pointed out that special factors included the large variation range of working medium＇s thermophysical property when transferring from hygrometric state to dry state and spanning critical temperature, the extension of steam flow in superheater systems, the augmentation of cumulative effect on steam temperature deviation and the change of water to coal ratio, etc. The one-sided spray water flux must be controlled, if it is too much, the flow deviation will be aggravated, even the critical flow will be caused, and thus the steam temperature deviation will be enlarged. The variable trend of steam temperature deviation reflected by practical examples can be concluded as follows. The steam temperature deviation is biggest in low-load operation stage, and is amplified near critical pressure, and the outlet steam temperature deviation of superheater can be controlled below design point about 5℃. And the exceed temperature, tube explosion or flow deviation caused by technical quality such as product, assemble and welding should be highly attended.

关 键 词：超超临界锅炉 过热器系统 汽温偏差 工质热物理特性 偏差累积 

分 类 号：TK229.2[动力工程及工程热物理—动力机械及工程]