An Experimental Investigation on Solid Acceleration Length in the Riser of a Long Circulating Fluidized Bed

Systematic experimental work was conducted to investigate the solid acceleration length in a 16m long circulating fluidized bed riser with fluid cracking catalyst particles over a wide range of operating conditions. A more feasible method is proposed to determine the acceleration length from the measured axial profiles of pressure gradient (or apparent solid holdup). With this new method and large amount of experimental data, a clear picture on the variation of the acceleration length with both solid circulating rate and superficial gas velocity is obtained.It is found that the acceleration length increases generally with increasing solid flow rate and/or decreasing gas velocity. However, the trend in variation of the acceleration length with operating conditions are quite different in different operation ranges. Reasonable explanations are suggested for the observed variation patterns of acceleration length.

常州金坛区新旧水厂切换方案制定与实施

为解决常州市金坛区的用水问题,近期建成规模为30×10^(4) m^(3)/d的长荡湖水厂,在新水厂投入运行时,容易发生浑黄水、水流方向及流速变化等新旧水厂切换问题。为了降低对供水管网水压和水质的不利影响,通过利用软件模拟,提出可行的水厂切换方案,实施后成功实现了新旧水厂供水方式的切换。