关于循环流化床锅炉的给煤问题

Coal Feed in Large Capacity Circulating Fluidized Bed Boiler

循环流化床燃烧技术已被运行实践证明是可靠的洁净煤燃烧技术。目前影响循环流化床锅炉运行可靠性的一个问题是给煤的堵煤问题。分析了循环流化床锅炉中燃烧过程及煤颗粒进入炉膛后与气体、床料的混合过程,探讨了系统简化、性能可靠的前墙给煤的可行性,研究了这一给煤方式对燃料在床料中的混合效果及燃烧效率的影响。提出焦炭失活和气固混合欠佳是燃烧效率的主要影响因素,认为前墙给煤不会导致燃烧效率的下降,可靠性提高,便于操作。

Circulating fluidized bed combustion is improved an available clean coal combustion technology by the operation practices. However, its reliability is influenced by the the fuel feeding system. The combustion processes of coal particle and its mixture in bed material and gas is analyzed in this paper. The feasibility of coal feeding in the front wall in stead of return pipe of loopseal is discussed. And the effects of this coal feeding method on the mixing of fuel in the bed material as well as the combustion efficiency are investigated. It is suggested that the char deactivity and worse mixing of fuel in the gas are the key aspects that result in lower combustion efficiency, while the coal feeding in front wall does not cause lower combustion efficiency. However, the coal feeding system is more reliable and simple to operation.