管式炉中燃煤一次破碎特性的实验研究

燃煤在循环流化床锅炉中的破碎特性极大地改变了物料的粒度分布,对床内颗粒浓度、物料传热传质及煤颗粒的燃烧过程都有重要影响.由于循环流化床锅炉本身的复杂性及实验现象难于观察,在1台管式炉中研究了各种煤的一次破碎特性.实验发现,烟煤、贫煤、无烟煤和煤矸石的破碎形式并不相同.烟煤颗粒遵循环核分层破碎;贫煤、无烟煤既有表面破碎也有中心破碎,且少数颗粒因热爆性而迅速变为细小颗粒;煤矸石沿着颗粒层面发生破碎,破碎为一些碎片;此外,深入研究了颗粒粒径、炉膛温度和加热气氛对西山贫煤和阳泉无烟煤一次破碎特性的影响.

STUDY ON THE PRIMARY FRAGMENTATION CHARACTERISTICS OF COAL IN TUBE FURNACE

The fragmentation characteristic of coal in the circulating fluidized bed boiler greatly changes the particle size distribution of the bed material,and it has large effects on the granule concentration in the bed,heat and mass transfer of bed material and the combustion process of coal particles.Because of the complexity of the circulating fluidized bed boiler and the difficulty to observe the phenomenon,the primary fragmentation characteristics of different coals are determined in a tube furnace.The research results show that different kinds of coal have different fragmentation forms.Bituminous coal particles follow the ring nuclear-layer fragmentation form;lean coal and anthracite coal both show the center-fragmentation and the surface-fracture,some particles break into fine particles rapidly due to their heat explosion characteristics;the fragmentation of coal gangue happens parallel to its bedding planes,and the particles break into fragments.In addition,the effects of particle size,bed temperature and heating atmosphere on the primary fragmentation of Xishan lean coal and Yangquan anthracite coal are further researched.