1989 Volume 15 Issue 2 Pages 231-237
The continuous stirred-tank reactor (CSTR) has many advantages, such as large heat transfer coefficient and good controllability of temperature, but it has poor efficiency for reaction. To enhance the efficiency of the vertical CSTR, attachment of many partition plates in the reactor is very effective, especially for gas-liquid or solid-liquid flow. In the vertical multistage CSTR, back flow of liquid through each partition plate affects reactor performance.
In this study, the back flow ratio of liquid was measured with varying geometrical and operating conditions, such as impeller, free-area fraction and thickness of a partition plate, tank diameter, superficial liquid velocity and stirring speed. The lowest values were observed when a 4-blade turbine and a partition plate with opening located at the center of the tank were used. The back flow ratio increased with increasing stirring speed or free area fraction, and decreased with increasing superficial liquid velocity. In geometrically similar equipment, the back flow ratios were the same at the same mean residence time and mixing power per unit volume.
Finally, the procedure for design of the multistage CSTR with partition plates is discussed according to results obtained here.
