A Suitable Disengagement: Adventures In a Multi-Phase Reaction System

A Suitable Disengagement:  Adventures in a Multi-phase Reaction System

Cheryl Teich
The Dow Chemical Company, Spring House, PA
Core R&D/Process Chemistry and Development

In the early business development of a niche specialty product, a small-scale CSTR provided adequate volumes.  The product is generated as a gas that forms through a complex reaction pathway and must disengage from a mixture containing two distinct solids and multi-component liquid and gas phases.  Extended product holdup can lead to yield loss via byproduct and mer formation, and even to a potentially hazardous condition.  Safe and successful operation of the process relies on balancing the reaction pathway with adequate reactor mixing and gas disengagement.  This had been achieved with the existing process through extensive operating experience.

The potential for step growth in the business led to an examination of reactor options to supply the larger volumes.  A concern was that a larger CSTR might not provide adequate gas disengagement and that the process would suffer as a result.  The first step in generating the next generation reactor design was to capture process understanding in the process scheme shown below.

Development of the process scheme led to an examination of the scale-independent chemistry and its interaction with equipment-specific agitation configurations.  The development program used various laboratory reactors and modeling tools such as DynoChem® and Aspen Plus® to deliver volume-specific recommendations on reactor type and designs to meet the growing business needs.