Flow Hydrodynamics in Pyridine Synthesis Coupled Reactor Feed Injection Zones

Abstract

The flow hydrodynamics in the pyridine synthesis coupled reactor feed injection zones was investigated by cold mode experiments. The results showed that the feed injection zones can be subdivided into three regions, which are the dense bed region, feed injection region, and fast fluidized bed region. A dense bed is formed in the bottom of the feed injection zones, which is to be minimized as to avoid over-reaction. To determine the height of the dense bed, the catalyst concentration was used to determine the boundary. The results showed that the height of the dense bed is affected by operating conditions like superficial gas velocity, catalyst circulation rates, and the axial positions of the nozzles. The height of the dense bed increased with the increase in the catalyst circulation rate, the decrease in the feedstock to primary gas ratio, and the increase in the axial position of the nozzles. Based on experimental results and jet trajectory function proposed in previous reports, an empirical model is proposed to model the height of the dense bed. The prediction results agreed well with experimental results with an average deviation of 3.9%. Based on prediction results, the optimal operating conditions are suggested as to minimize the height of the dense bed.