Anis Bakhshi - Department of Chemical Engineering, College of Engineering Isfahan University, Isfahan, Iran
Amir Rahimi - Department of Chemical Engineering, College of Engineering Isfahan University, Isfahan, Iran

In present study a mathematical model is developed in order to examine the effects of heat and mass transfer on removal efficiency of particulate matters in Venturi type scrubbers. The governing equations including the particulate concentration, gas temperature, droplets temperature, droplets diameter, and droplets velocity equations are obtained by using the conservation laws and solved numerically. To validate the mathematical model, necessary data was measured and collected in a commercial cement plant that uses this type of scrubbers for controlling of air pollution. A good agreement between plant data and the model predictions is noticed in general, and results obtained from the model reveal that the existing of temperature difference between gas and liquid droplets decreases the overall removal efficiency of particulate matters. This is due to very rapid reduction of relative velocity between droplets and gas, resulted from heat and mass transfer between them especially in throat section of Venturi. The effects of variation of various operating parameters on the extent of reduction in removal efficiency were examined by using the model. This study confirms that in most industrial applications of Venturi scrubbers it is necessary to use a direct or an indirect cooling tower for decreasing of gas temperature before entering the Venturi.

Venturi scrubber; Evaporation; Condensation, Mathematical model