L阀控制飞灰循环特性的研究

Investigation into Control Characteristics of Fly Ash Flow in an L Valve

飞灰循环回燃是提高鼓泡床锅炉燃烧效率的一项投资少、效果显著的技术,而控制合理的循环量是实现飞灰循环回燃技术的关键。飞灰循环系统通常由旋风分离器、立管和控制阀组成。由于工作条件恶劣,控制阀多采用非机械阀。非机械阀是70年代发展起来的固体循环调节阀。由于没有移动部件,适合在高温高压及有磨损、腐蚀等环境中运行,已被广泛应用。非机械阀通过调节松动风量来改变气-固在立管及阀内的流动,从而控制固体循环量。L阀和J阀是其中较典型的形式。对于其原理及易于控制的Geldart B类物料在其中的流动特性,Knowlton和Hirsan等曾作过深入研究。

Fly ash belongs to the Geldart A class. Its flow can not be controlled smoothly and widely with ordinary L valve. In this research, it was improved by means of appropriate arrangement of the airation air, so that its control characteristics became as good as those of the Geldart B materials. The experiment results are shown in this paper.