摘要
传统的机组全工况分析是基于机组稳定运行状态的分析,由于非稳态工况的出现日益频繁,提出了同时包括稳态和非稳态工况的广义全工况的概念,给出了其相应的热力学第一定律评价指标——热利用率和热储率.在此基础上,采用水冷壁分段的计算方法,建立了超临界直流锅炉水冷壁广义全工况热力学第一定律分析模型.以某1 913 t/h锅炉水冷壁为例进行了计算,获得了水冷壁广义全工况的热量组成和分布结果.结果表明：对于本例中的多种升负荷的非稳态过程,水冷壁的热储率约为0.9％～4.1％;亚临界压力下的蒸发段和热水段蓄热约占水冷壁总蓄热的95.8％～98.2％,而超临界压力时不存在蒸发段,其余各段的蓄热所占比例基本相当;当负荷固定时随负荷变化率的增大,热储率增大,热利用率降低,当负荷变化率固定时,热储率随负荷的增大而减小,热利用率升高.
Traditional analysis of full work conditions analyze the study of each running state when thermal power unit is under steady-state operation condition in coal-fired power unit. Due to increasingly frequent emergence of unsteady-state conditions in China, this paper proposes a concept of ＂generalized full work conditions＂ which includes steady-state and unsteady-state, and appropriate evaluation indexes （heat utilization rate and heat storage rate） on perspective of the First Law of Thermodynamics. A segmented method in calculation of water cooled wall is adopted, the first law of thermodynamics analysis model of generalized full work conditions is established on energy balance equation. Water cooled wall of a 1 913 t/h boiler is calculated, heat distribution and composition of water cooled wall in generalized full work conditions are acquired, the results are as follows, for several load rising non-steady processes in this case, the range of heat storage rate of water cooled wall is about O. 9% 4.4%; proportion of heat storage of evaporation section and hot water section to the total heat storage of water cooled wall is 95.8-98.2% under subcritical pressure, and under su- percritical pressure, there is no evaporation section, the heat storage proportion of the other sections are quite close; the heat storage rate increase and the heat utilization rate decrease with rise of load change velocity when load is fixed, and this two indexes change to the con- trary with rise of load when load change velocity is constant.
出处
《锅炉技术》
北大核心
2015年第1期1-7,26,共8页
Boiler Technology
基金
国家自然科学基金资助项目(51006033
51025624)
国家自然科学基金联合基金项目资助项目(U1261210)
中央高校基本科研业务费专项资金(10ZG03
13MS12)
关键词
广义全工况
蓄热
水冷壁
超临界机组
generalized full work conditions
heat storage
water cooled wall
supercritical unit
