Evaluate a batch process for a new type of polymer-based encapsulation product and provide engineering support to scale up the pilot scale process to large scale product reactors.
BATCH PROCESS EVALUATION AND SCALEUP PROCESS DESIGN
The client manufactures specialty chemicals. The client contacted Process Engineering Associates, LLC (PROCESS) to evaluate a batch process for a new type of polymer-based encapsulated product and to provide engineering support to scale up the pilot scale process to large scale product reactors. Anomalies had been found between the results from pilot batch data and a few large scale trial batch runs from the production facility. PROCESS was assigned the task of reviewing the available data and providing assistance with process and equipment design and sizing for the full scale production. Project tasks included:
- Review existing pilot data to define the critical process parameters
- Recommend additional testing to clarify the critical process parameters
- Evaluate the use of an external heat exchanger rather than the existing reactor jacket
- Size equipment to optimize product quality, consistency, and capacity.
PROCESS first evaluated existing data to determine which process operating parameters were critical to achieving acceptable product quality. The parameters evaluated included reaction temperature, reaction time, viscosity, emulsion time, shear mixer speed, and shear mixer flow rate. Data review and observation of trial batches revealed that only a few of the operating parameters were truly important to product quality and consistency. Additionally, differences in product quality that had been observed between pilot and large trial batches were in large part explained by differences in operating parameters used for the different batch sizes. Additional testing was recommended and carried out to clarify the critical operating parameters.
The next step in the evaluation was to determine the effects of proposed changes to the equipment configuration. These changes were contemplated to allow better control of the captive active chemical addition and emulsion steps, as well as to meet desired capacity requirements by reducing batch heating and cooling times. An external recirculation loop with a pump, shear mixer, and heat exchanger was proposed for these purposes. An external shear mixer had been used by itself in the pilot process for the captive active chemical addition and emulsion steps, but its performance was constrained by viscosity effects as the batch progressed. Heat transfer in the pilot testing and the large trial batches had been limited by the reactor jacket and by fouling of the reactor wall. Pilot testing was performed with an external pump in combination with a shear mixer and heat exchanger. Data from these runs were also analyzed to verify the performance of this arrangement. When operated in a way that observed critical process parameters, the external heat exchanger loop was demonstrated to maintain product quality while decreasing batch time and fouling.
The final part of the evaluation was to size the equipment to be used in the full scale production facility. In-house spreadsheet calculations were developed to predict heating and cooling times for the production scale reactors, concentrations in the reactor and the recirculation loop as a function of time, and the desired recirculation flow rate. This information, along with the previous data analyses, was used to size the batch equipment for the full scale production facility. The equipment size and the process design maintain those process parameters that are critical to product quality. The equipment sized as part of this effort included the shear mixer, recirculation pump, heat exchanger, reactor, and agitator.
- Specialty Polymers
- Process troubleshooting and optimization
- Batch processing analysis
- Polymers process engineering
- Equipment evaluation and sizing
- Pilot to production process scaleup