Gas-Phase Mass Transfer in a Centrifugal Contactor

Abstract

The liquid-side mass transfer rate in a centrifugal gas-liquid contactor has been reported to be several times higher than that in conventional packed beds. However, no direct measurement of the gas-side mass transfer coefficient has been reported. We present experimental studies on gas-side mass transfer in a rotating packed bed with wire-gauze packing. Contrary to expectations, the gas-side mass transfer coefficient was much lower than that in conventional packed columns. An analysis of the gas flow, based on the equations of motion, revealed that the gas undergoes solid-body-like rotation in the rotor because of the drag offered by the packing. Therefore, the mass transfer coefficient should be in the same range as that in conventional packed columns. The lower value of the coefficient found experimentally is attributed to liquid maldistribution. The possibility of enhancing the mass transfer coefficient by enhancing the slip between the gas and the packing was explored by using a stack of closely spaced disks as the packing. Mass transfer studies with a pair of disks were conducted. Higher throughputs and mass transfer rates than those with the wire-gauze packing were obtained. A stack of disks as packing appears to hold promise.

Evaluation of alkanolamine solutions for carbon dioxide removal in cross-flow rotating packed beds

“…Therefore, the gas-liquid mass transfer would frequently be enhanced by a factor of 10-100 and the dramatic reduction in the equipment volume would be achieved, thereby reducing the capital and operating costs [5]. A variety of studies have appeared in which the attention was focused on the applications of the countercurrent-flow RPB in diverse processes such as distillation [6][7][8][9][10][11], absorption [12][13][14][15][16][17][18][19][20][21][22][23][24][25], stripping [26][27][28][29][30], deaeration [31][32][33][34][35], reactive precipitation [36][37][38][39][40][41][42][43][44][45][46][47], and ozone oxidation [48][49][50][51]…”

Feasibility of ozone absorption by H2O2 solution in rotating packed beds

“…Therefore, the size of the RPB would be dramatically reduced and, thus, the capital and operating costs would be reduced simultaneously [5]. The RPB can be used to enhance the O 3 transfer from gas phase to liquid phase based on the studies, which presented that the RPB has a wide applicability in a variety of gas-liquid contacting processes such as distillation [6,7], absorption [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], stripping [24][25][26][27], deaeration [28][29][30][31][32], reactive precipitation [33], and ozone oxidation [34][35][36][37].…”

Process Intensification of Steel Slag Carbonation via a Rotating Packed Bed: Reaction Kinetics and Mass Transfer

“…We know that the KGa in a packed bed from the two-film theory can be described by two-film theory as Eq (2): (2) where H is the Henry's law constant expressed as the ratio of the partial pressure in the gas phase to the mass concentration in the liquid phase. On the other hand, Kelleher and Fair (1996) [10] extracted an overall volumetric mass transfer coefficient from the ATU definition for the gas side and combined with the results obtained in the literature [18]: (3) It was noted that KGa increases with the gas flow rate, the liquid flow rate, and mainly with the rotor speed [19]. It is usually difficult to obtain mass transfer coefficients separated from volumetric mass transfer coefficients kLae and kGae since the effective interfacial area between the liquid and vapour phase is usually not known [10].…”