分离式低温省煤器与暖风器系统经济性分析

Economic analysis for separated system of low pressure economizer and air heater

针对低温省煤器与暖风器联合系统经常出现的低温省煤器解列后暖风器无法投运等问题,本文提出了一种分离式低温省煤器与暖风器系统,该系统中低温省煤器与暖风器为2个相互独立的系统,利用7段抽汽来加热暖风器,降低了暖风器热源的品位,同时喷淋系统吸收了部分乏汽的热量,增加了节煤量。以内蒙古某600 MW机组的应用方案为例,对分离式系统、联合系统与纯低温省煤器系统的经济性进行了计算分析。结果表明:分离式系统比纯低温省煤器系统节煤量大1.46 g/(k W·h),比联合系统节煤量大0.46 g/(kW·h);分离式系统负荷越低,节能效果越明显;喷淋系统环境温度越高节煤量越大,负荷降低后节煤量呈下降趋势。

In the combined system of low temperature economizer and air heater, the heater usually can not be put into operation after the low temperature economizer stopped running. To solve this problem, a separated system combing the low temperature economizer with the air heater was proposed. In this system, the low temperature economizer and the air heater are two independent systems, the air heater is heated by No.7 extraction steam, which reduces the quality of the air heater＇s heat source. At the same time, the spraying system absorbs the heat of part of the exhaust steam, which increases the coal saving capacity. Taking a 600 MW unit in Inner Mongolia as the example, economic analysis for the separated system, combined system and the conventional low temperature economizer system were carried out. The results show that, the energy conservation potential of the separated system was 1.46 g/（kW·h） and 0.46 g/（kW·h） higher than that of the pure low temperature economizer system and the combined system, respectively. For the separated system, the energy conservation potential was better at lower load. In the spraying system, the energy conservation potential was better at higher environmental temperature, but decreased at lower load.