循环流化床锅炉旋风分离器中心筒的外压稳定性分析

Stability analysis for external pressure of central cylinder of cyclone separator in CFB boiler

针对循环流化床(CFB)锅炉旋风分离器中心筒出现的塑性变形问题,本文根据中心筒受力形式,建立了其一端简支或固支、另一端自由的承受外压力的圆筒分析模型,对中心筒发生塑性变形的机理进行了分析。结果表明:在外压力作用下,旋风分离器中心筒内部会形成较大的环向弯曲应力,当中心筒的刚度不足时,弯曲应力直接导致中心筒失稳;当刚度满足要求时,由于中心筒在高温环境下长时间运行,弯曲应力会造成中心筒的外压失稳变形或蠕变变形,进而出现椭圆或多波形变形特点。对此,可以通过设置加强圈提高中心筒的刚度,以避免发生失稳变形。

To solve the plastic deformation problem occurred in central cylinder of cyclone separator in circulating fluidized bed(CFB) boiler, according to the force form of the central cylinder, an analytical model of the cylinder with simple support or clamped support on one end, free on the other end is established in this paper. The results show that, under the action of external pressure, large circumferential bending stress is formed in the central cylinder of the cyclone separator. When the stiffness of the exit tube is insufficient, the bending stress will directly lead to the instability of the cylinder. When the stiffness meets the requirements, the bending stress will cause the instability deformation or creep deformation of the central cylinder under external pressure due to long-time operation of the central cylinder at high temperature. This deformation has the characteristics of ellipse ormulti waveform of the instability deformation as the general external pressure cylinder. Measures like setting the stiffening ring to improve the stiffness of the central cylinder can be taken to avoid the instability deformation.