无汽水分离器直流余热锅炉启动过程仿真研究

Simulation of a Once-Through Heat Recovery Steam Generator Without Separator During Start-Up

无汽水分离器直流余热锅炉的冷态启动过程复杂、启动方案多样、启动时间长,优化其启动过程具有重要意义。以某无汽水分离器的立式直流余热锅炉为研究对象,建立了其动态仿真模型,通过仿真试验研究了烟气设计条件下,冷态启动过程中管组预热时长和高压给水流量对锅炉出口工质温度的影响。结果表明:工质温度稳定所需的时间随管组预热时间的增加而增长,随高压给水流量的增加而缩短;给水流量越大,工质稳定后的温度越低;在满足启动参数要求的前提下,锅炉通入烟气的同时,送入给水,工质温度稳定所需的时间最短;在启动初期加大流量给水,在消耗一部分管组蓄热后,再减小给水流量,此运行方式可以有效缩短工质参数达到稳定所需的时间。

The cold start-up process of the once-through heat recovery steam generator(HRSG) without separator is complex, with various start-up schemes and long start-up time, so it is of great significance to optimize the start-up process. In this paper, a vertical HRSG without separator is the research object, and the dynamic simulation model are presented.Under the gas design conditions, the effects of the preheating time of tube package and the high pressure inlet water flow rate on outlet temperature of working medium during cold start-up are simulated. Results illustrate that the stabilization time of working medium increases with the increase of preheating time of tube package, and it decreases with the increase of high pressure flow rate;the larger the water flow rate, the lower the stable temperature of working medium;on the premise of satisfying start-up parameters, the working medium stabilization time is the shortest when the flue gas and the feed water are injected at the same time;the working medium stabilization time can be reduced by selecting a proper large water flow rate at the initial stage of start-up and then reducing it back to normal value when the heat accumulation of the tube metal is consumed.