流化床内生物质石英砂混合流动压力脉动频谱特性

Frequency spectrum characteristics of pressure fluctuation in fluidized bed with biomass particles and quartz sands

为考察生物质颗粒的添加对流化床流动特性的影响,研究不同静止床高和生物质添加量下矩形流化床的压力脉动频谱特性,床料选用0.8 mm粒径的石英砂,柱形生物质颗粒直径×长为10 mm×10 mm。研究结果表明：当不添加生物质颗粒时,高静止床高下压力脉动信号的功率谱密度图在0-5 Hz区间会出现主频。当处于低静止床高且生物质添加量较少时,功率谱密度图主频完全消失;当生物质添加量较多时则会出现1个明显的主频,该主频随气速的增大而增大。当处于高静止床高时,只有在低气速下,生物质添加才会对压力脉动频谱特性有明显影响。

To research the influences of fluid characters on fluidized bed added biomass particles, the pressure fluctuation spectrum behaviors at different static bed heights and biomass weight were investigated in a rectangular fluidized bed. The quartz sands with the diameter of 0.8 mm and cylinder-shaped biomass particles with both of the diameter and length of 10 mm were adopted as bed materials. The results show that power spectral density has an obviously main frequency between 0-5 Hz when the static bed height is high and without biomass particles. The main frequency of the power spectral density disappears completely, when the static bed height is low and a small amount of biomass is added. But an obvious main frequency occurs when a large amount of biomass is added. When the static bed height is high, the biomass particles influence the flow of gas only at a low superficial gas velocity.