Chromatography Column Scale-Up
One chromatography column developer was having challenges scaling up an existing design to a larger version. Our team worked with the manufacturer using Computational Fluid Dynamics (CFD) to understand the reasons for the reduced performance. CFD modeling was used to pinpoint reduced performance when moving from existing, small scale units to upscaled columns.
In the work we peformed, we were able to validate a CFD model and calibrate porous dispersion coefficients for the existing column. Moving to the larger column, however, initial results could not be reproduced with CFD. It was found that for the upscaled column, the synthetic textile mesh that forms the boundary between the distributor and the packed bed had deformed under the packing pressure of the column, such that the distributor was pinched off, and the outer radius of the packed bed was starved of flow. Computing the deformation of this mesh around the radial rib supports—and including this effect in the CFD simulations—showed that the upscale experimental results could be reproduced. The solution was verified in subsequent experiments.
Through a recommended design change, we were able to show that the high level of performance typical of the existing column could be reproduced in the upscaled column. The improved design is also able to be packed more consistently, and operates at a lower pressure loss than the original.
Capability
Civil InfrastructureServices
Process EngineeringRelated Projects
An existing roof vent arrangement was allowing rainwater to enter the Pot Room. Alden supported efforts to develop a roof vent geometry to eliminate the intrusion of rain water. The purpose of the CFD study was to ensure that the roof vent modification did not increase pot room temperature levels beyond specified limits for workers in the plant.
To evaluate the existing and proposed Pot Room arrangements, thermal and fluid flow profiles in the immediate vicinity of the pots were determined based on air flows through the plant floor and wall mounted vents. The detailed CFD model was developed from plant drawings to include all major basement, pot room and roof venting geometries. The surrounding ambient environment was included with quiescent atmospheric conditions and average ambient temperature. Thermal losses form the pots to the pot room air and from the pot room to the environment were included in the analysis. The results of the CFD modeling showed that the proposed modification to the roof venting arrangement was acceptable and would not increase the temperature in the worker-occupied spaces by more than 2 degrees F.
}', 13='{type=image, value=Image{width=2250,height=847,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/Smelter-Pot-Room/Smelter-Pot-Room-Diagram.jpg',altText=''}}', 14='{type=string, value=Thermal and fluid flow profiles were evaluated for both existing and proposed venting arrangements}', 15='{type=image, value=Image{width=2250,height=847,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/Smelter-Pot-Room/Smelter-Pot-Room-Temperature-CFD.jpg',altText=''}}', 16='{type=string, value=Heat transfer from the pots to the air passing through the pot room were evaluated}', 17='{type=image, value=Image{width=2400,height=869,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/Smelter-Pot-Room/Smelter-Pot-Room-Ventilation-CFD.jpg',altText=''}}', 18='{type=string, value=CFD confirmed the efficacy of the modified roof vent system to maintain safe temperatures.}', 25='{type=number, value=0}', 27='{type=number, value=1}', 28='{type=number, value=0}', 29='{type=number, value=50}'}
Civil Infrastructure
Smelter Pot Room Roof Ventilation System
Read how a CFD study ensured that a roof vent modification did not increase pot room temperature levels beyond safe levels
Plant McDonough, owned and operated by Southern Company, has experienced excessive siltation at the makeup water intake. The intake uses cylindrical wedgewire screening within an intake originally designed for much larger, once-through cooling water flows. Flow modeling was performed to provide a viable passive solution to reducing the sediment accumulation at the intake. To model the geometric details of the system accurately, a field survey was performed prior to the flow modeling efforts. The flow study included both CFD modeling and scale physical modeling.
For this investigation, Alden developed a 1:20 scale live bed physical model. This model was extremely well tuned to reproduce the behavior of bed load sediment. Even with the very fine crushed walnut shell particles, however, it was challenging to reproduce the behavior of suspended load. The use of a high fidelity CFD model, therefore, proved extremely useful for this project, in that suspended load is generally very accurately tracked with CFD models, which are not well validated for bed load simulation. By using the two together, the two extremes of sediment transport are captured, and developing a solution that covers this range has a high likelihood of success.
}', 13='{type=image, value=Image{width=3872,height=2592,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/Plant-McDonough/Physical-Model-Plant-McDonough.jpg',altText=''}}', 14='{type=string, value=A 1:20 live bed physical model was constructed to reproduce the behavior of suspended sediment load}', 15='{type=image, value=Image{width=2977,height=2386,url='https://20952198.fs1.hubspotusercontent-na1.net/hubfs/20952198/PROJECTS/ALDEN/Plant-McDonough/Original-Construction-Plant-McDonough.jpg',altText=''}}', 16='{type=string, value=Image of the plant under original construction, provided courtesy of Southern Company}', 25='{type=number, value=0}', 27='{type=number, value=1}', 28='{type=number, value=1633353195000}', 29='{type=number, value=60}'}
Civil Infrastructure | Hydrology Hydraulics and Fluids
Plant McDonough Intake Modification
CFD and physical model study to assist in the evaluation of a solution to reduce the sediment accumulation.