锅炉空气预热器并联旁路烟道最佳容量选择
第47卷 第7期 热 力 发 电 V ol.47 No.7
收稿日期：2018-02-09
基金项目：国家自然科学基金项目(61202121212)
Supported by ：National Natural Science Foundation of China (61202121212)
第一作者简介：李伟科(1979-)，男，高级工程师，主要研究方向为热能相关节能新技术，Liweike@https://www.360docs.net/doc/a815718409.html, 。
锅炉空气预热器并联旁路烟道最佳容量选择
李伟科
（中国能源建设集团广东省电力设计研究院有限公司，广东 广州 510663）
[摘 要]锅炉空气预热器（空预器）并联旁路烟道系统是锅炉尾部烟气热量深度利用的重要方式，
机组要获得最优的热效率需选择最佳的旁路烟道容量。本文通过热量守恒法对锅炉空预器
并联旁路烟道容量及热负荷公式进行推导，并结合某超超临界1 000 MW 等级燃煤机组对
旁路烟道容量及热负荷进行计算，从而确定了旁路烟道最佳容量。结果表明：旁路烟道最
佳容量选择与旁路烟道出口烟温、空预器冷端烟气与冷风平均温差和暖风器出口平均风温
密切相关；机组在同等条件下，对比空预器冷端平均温差分别为40 ℃和50 ℃的计算结
果得到，暖风器出口平均风温为50 ℃时，旁路烟道热负荷均为最大值，分别为51.601、
43.261 MW ，此时旁路烟道最佳容量分别为0.174、0.145。此结论可为火电厂锅炉空预器
并联旁路烟道系统设计提供指导。
[关 键 词]空预器；并联旁路烟道；最佳容量；暖风器；热量守恒法；热负荷；热经济性
[中图分类号]TK11+4 [文献标识码]A [DOI 编号]10.19666/j.rlfd.201802013
[引用本文格式]李伟科. 锅炉空气预热器并联旁路烟道最佳容量选择[J]. 热力发电, 2018, 47(7): 69-74. LI Weike. Optimal capacity selection of parallel bypass flue for boiler air preheaters[J]. Thermal Power Generation, 2018, 47(7): 69-74.
Optimal capacity selection of parallel bypass flue for boiler air preheaters
LI Weike
(China Energy Engineering Group Guangzhou Electric Power Design Institute Co., Ltd., Guangzhou 510663, China)
Abstract: The parallel bypass flue system for boiler air preheater is an important method for advanced utilization of boiler tail flue gas heat. The optimal capacity of parallel bypass flue is selected for optimal thermal efficiency of units. The formula of capacity and heat load of parallel bypass flue for boiler air preheater is derived based on the law of heat conservation. Combined with an ultra-supercritical 1 000 MW coal-fired unit, the capacity and heat load of bypass flue are calculated so as to select the optimal capacity of bypass flue. The results show that, the optimal capacity selection of bypass flue is closely related to the flue gas temperature at the outlet of the bypass flue, the average temperature difference between the flue gas and the cold air at the cold end of the air preheater, and the average air temperature at the outlet of the air heater. Under the same conditions, according to the calculation results of the average temperature difference at the cold end of the air preheater (40 ℃ and 50 ℃), when the average air temperature at the outlet of the air heater is 50 ℃, the maximum heat load of the bypass flue is obtained, which is 51.601 MW and 43.261 MW, respectively. At this time, the optimal capacity of the bypass flue is 0.174 and 0.145, respectively. It can provide guidance for the design of parallel bypass flue system for boiler air preheater in thermal power plants.
Key words: air preheater, parallel bypass flue, optimal capacity, air heater, law of heat conservation, heat load, thermal economy
锅炉尾部烟气热量深度利用是电站实现节能
减排的重要手段，近年来行业内提出了多种烟气余
热利用系统[1-3]，其中锅炉空气预热器（空预器）
并联旁路烟道系统技术经济性较好，节能效果
显著[4-6]。 与传统的低温省煤器系统相比，旁路烟道系统的烟气热量利用能级较高。从理论上分析，旁路烟道系统容量越大，用于加热汽轮机侧的热量越大，汽轮机侧效率越高[7]；但用于加热空气的烟气热量随之减少，使得空预器出口的热风温度降低，空预万方数据