Modeling the hydrochlorination reaction in a laboratory-scale fluidized bed reactor

Abstract

In the manufacturing process of high purity, electronics-grade silicon, the hydrochlorination reaction step for converting silicon tetrachloride (STC) to trichlorosilane (TCS) is usually carried out in a fluidized bed reactor. However, the design and operation of industrial-scale fluidized bed reactors for the conversion of STC to TCS is currently based on ad hoc rules of thumb and operator experience rather than on reaction engineering principles. In this paper, a fluidized bed model was developed by using the Kunii–Levenspiel fluidization framework. The predictive capabilities of this model were tested on laboratory-scale experimental data from the literature. It is shown that the modified Kunii–Levenspiel model accurately predicts the no catalyst addition and copper catalyst addition experiments of the hydrochlorination fluidized bed with an average percent difference of less than 6%. By making a suitable adjustment to catalytically active iron content, the model prediction is in excellent agreement with experimental data with hydrochloric acid in the feed stream. The modified Kunii–Levenspiel model is well suited for use in scale-up calculations for an industrial reactor as all the parameters are physically reasonable and can be predicted for larger reactors.