Abstract: The production of pseudo-boehmite by NaAlO₂-Al₂(SO₄)₃ process is a rapid neutralization reaction, the mass transfer effect of reactants directly affects the product properties, and the structure of stirred reactor influences mass transfer effect. When the production capacity of industrial production is expanded, the amplification effect of stirred reactor becomes the key to affect the product properties. The computational fluid dynamics (CFD) software fluent was used to numerically simulate three kinds of scale reactors: laboratory small reactor, industrial one-volume reactor and double-volume reactor. The effects of rheological properties of the reaction material, macro mixing time and height-diameter ratio of the reactor was investigated on the laboratory small reactor. Combined with the experimental results and the reaction mechanism analysis, it was found that in order to obtain products with larger pore volume, the flow pattern in the reactor should ensure rapid mixing and high super-saturation at the feeding site and low super-saturation at the lower part of the reactor. The simulation results showed that there was no strong mixing at the feeding site and local fast circulation at the bottom of the reactor in the industrial one-volume reactor, while there was strong mixing at the feeding site and fast circulation at the bottom of the reactor in the double-volume reactor. The results of industrial production showed that the pore volume of the product from double-volume reactor was better than that from the one-volume reactor. Therefore, when the reactor was scaled up to quadruple-volume reactor, taking the flow pattern in the quadruple-volume reactor to form the same flow pattern of the double-volume reactor as the objective, the parameters of the quadruple-volume reactor such as the height-diameter ratio, the size of the agitator, the structure of the reactor body and the installation mode of the baffle were optimized by numerical simulation method. The dimensions of the quadruple-volume reactor and its internal components were calculated, the quadruple-volume reactor was designed and manufactured, and the industrial test was carried out on the industrial plant of SINOPEC Catalyst Co. Ltd.,Changling Division. The results showed that the pore volume of the product from quadruple-volume reactor was the same as that from the double-volume reactor under the same process conditions, which successfully avoided the scale-up effect of the reactor.

Key words: pseudo-boehmite, stirred reactor, scale-up, pore volume, amplification effect