A NOVEL HEAT EXCHANGER DESIGN FOR SLURRY BUBBLE COLUMNS
S. C. Saxena
Department of Chemical Engineering University of Illinois at Chicago, Box 4348, Chicago, IL 60680, USA
The characteristics of a thirty-seven 19mm diameter tube bundle heat exchanger immersed in a 0.305m diameter slurry bubble column are investigated in conjunction with air-water, air-water-glass bead, nitrogen-Therminol, nitrogen-Therminol-magnetite systems. The operating parameters range for superficial gas velocities up to about 0.12 m/s, temperatures up to about 523K, and slurry concentrations up to about 40 weight percent. It is shown that a reliable estimation of heat-transfer surface area is possible by determining the heat-transfer coefficient on the basis of a proposed correlation.
Heat-transfer coefficient data for the air-water system as a function of gas velocity and temperature are examined referring to a single tube, five- seven-and thirtyseven-tube bundles, and it is concluded that a tube bundle heat-exchanger configuration which occupies the entire column cross-section is preferable based on mass transfer and residence time considerations. This conclusion is upheld by measurements on two independent bubble columns of diameters 0.108 and 0.305 m. It is shown that reliable scale-up of heat-exchanger size is possible with the increase in bubble column diameter as long as its geometrical configuration and pitch value are retained.