(605d) Operation of Reactive Distillation Columns Disproportionating Trichlorosilane to Silane: Dynamic Impact of the Number of Reactive Sections

The disproportionation of trichlorosilane to silane features a three-stage consecutive reversible reaction with a rather unfavorable reaction kinetics of a near zero thermodynamic conversion. Reactive distillation columns (RDCs) appear to be an extremely favorable option for executing such a complicated reaction. In our previous research, we already showed that augmenting the number of reactive sections in process synthesis and design was beneficial to steady state economics. ^[1]More specifically, while the RDC with triple reactive sections (RDC-TRS) was advantageous over the RDC with double reactive sections (RDC-DRS), the RDC-DRS was over the RDC with a single reactive section (RDC-SRS). In the current research, the dynamics and control of the RDC-SRS, RDC-DRS, and RDC-TRS are to be studied and compared in great detail, with special attention focused on the dynamic impact of the number of reactive sections. It is found that the open-loop process gains, i.e., the one between the top product composition and reflux flow rate and the one between the bottom product composition and reboiler heat duty, increase gradually with the incremental arrangement of reactive sections. The in-depth comparison of closed-loop operation performance further demonstrates that the RDC-TRS and RDC-DRS exhibit improved anti-disturbance and tracking performance as compared with the RDC-SRS. These outcomes highlight definitely the great importance of the number of reactive sections to process design and operation.

LITERATURE CITED

[1] X. Zang, K. Huang, Y. Yuan, H. Chen, L. Zhang, S. Wang, and K. Wang; “Reactive Distillation Columns with Multiple Reactive Sections: A Case Study on the Disproportionation of Trichlorosilane to Silane,” Industrial and Engineering Chemistry Research, 56(3), 717-727 (2017).