Pressure drop in horizontal multi-tube liquid–solid circulating fluidized bed

Abstract

A horizontal liquid–solid circulating fluidized bed with transparent tube bundle is designed and built to investigate pressure drop. The effects of the operating parameters, such as the amount of added particles, circulation flow rate, and particle types on pressure drop in the horizontal circulating fluidized bed, are systematically investigated by using pressure sensors.Results show that the pressure drop is greater in liquid–solid two-phase flow than in single-liquid phase flow, except the system with POM1 particles. Pressure drop increases with the increase in the amount of added particles and circulation flow rate. The pressure drop fluctuates with the increase in the sediment velocity of the particle, and the amplitude of fluctuation decreases with the increase in circulation flow rate.The pressure drop ratio generally increases with the increase in the amount of added particles. In most cases, the pressure drop ratio rapidly decreases initially and then fluctuates or slightly increases with the increase in circulation flow rate. The pressure drop ratio also fluctuates with the increase in the sediment velocity of the particle, and the amplitude and laws of fluctuation depend on circulation flow rate.The difference in the pressure drop ratio at low circulation flow rate increases initially and then decreases with the increase in the amount of added particles. The difference in the pressure drop ratio decreases with the increase in the amount of added particles when the circulation flow rate is high. The difference in the pressure drop ratio decreases initially and then increases with the increase in the circulation flow rate when the amount of added particles is small. However, the difference in the pressure drop ratio decreases with the increase in the circulation flow rate when the amount of added particles is high.Phase diagrams are established to display the variation ranges of the operating parameters for pressure drop. The results combined with visualization investigation on particle distribution can be used to select relative conditions for uniform particle distribution in the horizontal circulating fluidized bed.