Opportunities to Increase Process Yields through Better Mixing of Reactants – A Case Study on Dichlorobutene Production

In vapor phase reactors two or more vapor/gas streams are mixed together. The gases are generally fed through nozzles. A critical problem with these reactors is the incomplete mixing of the injected gas/vapor streams leading to incomplete conversions. The degree of mixing is governed by the design of the feed nozzle. This presentation focuses on improving the yield of vapor phase chlorination of butadiene to dichlorobutene. Given the large volumes in which dichlorobutene is produced there is a considerable economic incentive in improving the yields of this process or in the alternative, in increasing the capacity without a loss of yield. Mere increase of the feed rates results in poor mixing leading to loss of yield. In this study computational fluid dynamics based models are used to understand the impact of the feed nozzle design on the mixing dynamics, conversion and selectivity. The nozzle design was optimized to maximize yields. A sensitivity study of the nozzle design on reactor dimensions was also conducted.