Transient Characterizations of Flow Pattern and Pressure Drop in a FixedBed BubbleColumn Reactor

A differential pressure sensor and an A/D converter with high frequency were employed to collect transient pressure drop data in a fixedbed bubblecolumn reactor. Methods were established to identify the flow patterns in the reactor. The ECT（electrical capacitance tomography）system was employed to investigate transient characteristics of gas holdup in different flow regimes. The waveforms，probability density distributions and power spectrum density distributions of pressure drops are significantly different in various flow regimes. So do transient gas holdups. The bed pressure drop gradient increases with the increase of gas and liquid flow rates. Comparison between experimental data and estimation shows that the revised Larachi's relationship and Khan and Varma's relationship can be used to predict frictional pressure drops in fixedbed bubblecolumn reactors of medium diameter（280 mm） with an averaged deviation of 18.0% and 14.5%, respectively.