Experimental Studies on Suspension of Solid Particles in a Low-Shear Stirred Vessel

摘要

A low-shear stirred vessel was explored. Experimental studies on the suspension of solid particles in solid-liquid and gas-solid-liquid systems were conducted to examine the performance of this new reactor. The method based on the power number curve was modified to determine the critical impeller speeds required for just complete off-bottom suspension of solids under non-gassed (N_(js)) and gassed conditions (N_(jsg)) in this reactor, and a PC-6A fiber-optic probe for the measurement of solid distribution was used to complementarily validate this method. A more homogeneous flow field was gained with a draft tube installed, so that the standard deviations of average shear rate and maximal shear rate are reduced. The modified power consumption method can determine N_(js) and N_(jsg), and the values of N_(js) with a draft tube are much lower than those without it. N_(jsg) increases slightly with increasing gas flow rate, and N_(jsg) with a higher solid weight fraction is larger in this lower-shear reactor.