Journal of Chemical Engineering & Process Technology
Open Access

Abstract

Effect of Surface Roughness on the Rate of Mass Transfer at a Vertical Cylinder Under Swirl Flow in Relation to Electrochemical and Catalytic Reactor Design

Mustafa SA, El-Gayar DA and Sedahmed GH

In order to enhance the rate of production of catalytic and electrochemical annular reactors used to conduct diffusion controlled reactions the effect of surface roughness on the rate of mass transfer at the inner cylinder of the annulus was studied under swirl flow. The effect of the following parameters on the rate of mass transfer was studied by the electrochemical technique: solution velocity, degree of roughness, physical properties of the solution, height of the inner cylinder and effect of drag reducing polymers. Roughness was made by cutting longitudinal V grooves in the inner cylinder transverse to swirl flow. The mass transfer data at the rough cylinder were correlated by the dimensionless equation: Sh=0.435 Sc0.328 Re0.86 (L/de)-0.53 (e/de)0.45 Drag reducing polymers were found to decrease the rate of mass transfer by an amount ranging from 5 to 23%. Importance of the present results for the design and operation of high space-time yield electrochemical reactors and biochemical reactors employing immobilized enzymes was pointed out. Also, the importance of the present results in the design and operation of membrane processes employing annular apparatus with a corrugated membrane was highlighted. By virtue of the analogy between heat and mass transfer the present results can be used to design more efficient double tube heat exchangers.