循环流化床锅炉燃烧系统动态特性分析

根据循环流化床锅炉(CFBB)的工作特点以及燃烧系统输入和输出过程变量间的耦合关系,讨论了CFBB的蒸汽压力和床温的动态特性。认为引起蒸汽压力变动的主要原因在于燃料量(内扰)和汽轮机调门的变化(外扰);而影响床温变化的主要因素是给煤量、风量、物料循环量的变动,并从传热和燃烧过程分析了这些因素间的相互耦合关系。这对CFBB燃烧自动控制系统的设计与调试,以及整个控制系统的可靠运行都至关重要。

Dynamic characteristic analysis of the combustion system on the circulating fluidized bed boiler

Based on the operating characteristics of the circulating fluidized bed boiler and the relationship between the input and output parameters of the firing system, the dynamic behaviors of the steam pressure and bed temperature of a CFBB were discussed. It was deemed that the factors resulting in variations of the steam pressure are the fuel rate and the opening of the steam-turbine governor valve. The factors which lead to variations of the bed temperature are the fuel rate, the combustion-air flow, and the amount of circulating solids. The relationship between these factors in the combustion and heat-transfer processes was analyzed, which is of great importance to the design and commissioning of the automatic control system for CFBBs, and to the reliability of operation of the whole control system.