(77c) Vision and Influence: Doug Leng’s Focus on Computational Fluid Dynamics at the Dow Chemical Company

In today's competitive marketplace, business must utilize every tool to make processes more efficient and productive. Although Computational Fluid Dynamics (CFD) has not yet reached routine application in the chemical industry, this tool has great promise. Knowing where and how to apply it is critical. CFD work at The Dow Chemical Company has included polymer processing, crystallization, static/jet mixing, batch mixing, reactor flow optimization, and incineration. This paper presents several examples how CFD was used to solve “real” challenges at the Dow Chemical Company. This work was first presented at the World User’s Association for Computational Fluid Dynamics (WUACFD) in Basel, Switzerland in 1993 and 1996. My participation in the WUACFD was made possible by Dr. Doug Leng – a senior research scientist at the Dow Chemical Company in the 1990s. The following projects will be reviewed and discussed in this short tribute to Dr. Leng (Doug) to demonstrate his vision and influence inside the Dow Chemical Company.

The first study examines heated air flow through a “Continuous Through-circulation Dryer” used to produce a super-absorbent used to produce diapers. This work focused on the upward directed flow in the dryer where four fans push heated air up through a permeable bed of “wet” material. Results helped explain why the product had a large range in moisture content. Results also yielded insight into possible ways to improve flow uniformity and increase dryer efficiency and plant capacity.

The second study considered flow into the top of a packed catalytic reactor. This work focused on flow distribution inside the tower head space and its impact on separation efficiency. Uniform flow to the bed surface plus is desired to maximize reactor performance. CFD results illustrated limitations in the current design. The model was used to optimize inlet reactant distribution and to investigate design changes for various inlet flow conditions. This work resulted in improved product yield and reactor throughput.

The last study presented results from our analysis of thermal oxidation of chlorinated hydrocarbons. This analysis utilized CFD with turbulent reacting flow submodels to simulate HCl/Cl2 generation inside the thermal oxidizer. Results of this work resulted in improved system operation with less environmental impact.

These three studies were originally conducted in Midland, MI for the Michigan Division of the Dow Chemical Company. This work was possible because of the vision Dr. Leng had for using CFD to solve real problems for the company.