小流量煤粉浓相气力输送特性

Low Flow Rate in Dense Phase Pneumatic Conveying Characteristics for Pulverized Coal

煤粉气力输送的稳定性严重制约着煤粉燃烧的效率及稳定性,研究了以干燥空气为载气的上出料发送罐小流量煤粉浓相气力输送系统的一般规律,即给煤率随特征参数如流化风量、补气器位置、发送罐压力、补充风量和L型提升管直径的变化。实验结果表明:流化风量增加,给煤率和固气比均先增大后减小;补气器位置的间距增加,给煤率先增大后减小;发送罐的压力增加,给煤率增大;补充风增加,给煤率减小,固气比减小;给煤率在一定范围内与L型提升管的面积成正比。在优化的流化风量和补气器位置的情况下,通过调整发送罐压力、补充风量可实现上出料发送罐小流量煤粉浓相气力输送的连续稳定运行,且给煤量连续可调。

The stability of the pulverized coal pneumatic conveying seriously restricts the efficiency and stability of pulverized coal combustion,the general rules of dry air as carrier gas top discharge blow tank of low flow rate in dense phase pulverize coal pneumatic conveying system were researched,namely,the influence of characteristic parameters like fluidizing gas flow rate,the location distance of air supplement unit,the pressure of blow tank,supplemental gas flow rate and diameter of the L-type conveying pipe on coal feeding rate. The results indicated that as the fluidization gas flow rate increased,the coal feeding rate and solid-gas rate increased at first then declined respectively. As the location distance of air supplement unit increased,coal feeding rate increased at first then declined. As the increase of pressure of blow tank,coal feeding rate increased. As the increase of supplemental gas flow rate,coal feeding rate and solid-gas ratio both declined. Coal feeding rate is proportional to the aera of L-type conveying pipe within a certain range. On the condition of optimized fluidizing gas flow rate and the location distance of air supplement unit,continuous and stable operation and adjustable coal feeding rate can be realized in the system of top discharge blow tank of low flow rate in dense phase pulverized coal pneumatic conveying by adjusting the the pressure of blow tank and supplemental gas flow rate.