Revamping distillation processes via dividing wall column technology
Consider the operational stability, thermodynamic efficiency, improved product quality, and operational stability from high-performance DWC separation technology
Gaurav Agrawal Sulzer Chemtech
I n today’s competitive and performance-driven industrial landscape, there is a growing need to revamp existing distillation processes. Operators are increasingly seeking ways to optimise performance without significant capital investment, achieve more precise separations to enhance downstream unit efficiency, and meet decarbonisation targets. These drivers are pushing the industry to explore inno- vative yet cost-effective solutions that can be integrated into existing infrastructure. Revamps offer a strategic path- way to modernise operations, enhance energy efficiency, increase throughput, and boost separation efficiency while leveraging existing assets. Among the various technologies available for process intensification, dividing wall column (DWC) technology stands out as a particularly promising solution. DWCs represent a significant advancement in the distillation approach by offering improved thermodynamic efficiency. The improvement in efficiency is achieved by physically separating the feed and product zones using an internal vertical wall and incorporating thermal coupling within a single column shell. This improved efficiency translates into tangible benefits such as reduced capital expenditure (Capex), lower util - ity consumption (Opex), increased throughput, improved product yield and quality, reduced plot space, and a smaller carbon footprint. These advantages make DWCs especially
attractive for revamp projects, where space constraints, budget limitations, and the need for minimal downtime are critical considerations. Design flexibility and configurations One of the most compelling features of DWC technology is its design versatility, which allows engineers to tailor configurations to meet specific process requirements. The placement of the dividing wall, which can be located at the top, middle, or bottom of the column, plays a crucial role in determining the separation efficiency and operational flex - ibility (see Figure 1 ). • Middle-wall configuration is the most commonly used configuration and typically offers the greatest savings in both Capex and Opex. It is particularly effective when the feed contains a significant amount of intermediate-boiling components, and the desired separation involves recover- ing high-purity side-products, making it especially suitable for applications where the intermediate product holds high commercial value. • Top-wall configuration is particularly beneficial when separating light and intermediate components is more straightforward than separating intermediate and heavy ones. It features two independent condensers, allowing precise adjustment for both the heavy-to-intermediate and intermediate-to-light separations. As a result, this setup offers enhanced control over product purities and provides
Top DWC
Middle DWC
Bottom DWC
Dual DWC
A
B
A
A
A
Feed (A+B+C+D)
B
Feed (A+B+C)
Feed (A+B+C)
Feed (A+B+C)
B
C
C
C
C
B
D
Figure 1 Top, middle, bottom, and dual DWC designs
15
Revamps 2025
www.digitalrefining.com
Powered by FlippingBook