Top Dividing Wall Column Technology – a Novel Approach
Most of the 150 DWCs in operation worldwide are middle dividing wall columns – primarily due to application requirements and industry acceptance.
In a middle DWC, however, it is a challenge to obtain two high-purity products due to size limitations (number of trays) and location of the wall. A novel approach to obtain two products from a single DWC is to move the dividing wall to the top of the column – effectively splitting the column into two separate overhead systems, both of which could be high-purity products. This approach has several advantages. First, the two sides stay completely independent with no remixing or contamination from each other. Second, two parallel areas inside one column tend to reduce the overall height (number of trays) of the column. Third, the two sides of the column can operate in different modes: one side as the rectification section and the other as the absorption section. The two independent sections inside the single column can be independently controlled by using appropriate control schemes, adding an extra degree of flexibility to the design.
Sulzer GTCTechnology recently designed and implemented the world’s first commercial application of a Top Dividing Wall Column in a C5-C6 Isomerization Unit for Bharat Petroleum Corporation Limited (BPCL), India, at their Mumbai refinery. This document provides details about the process and GTC’s process equipment technology (PET) division that fabricated and supplied the custom-designed column internals such as high-capacity trays and liquid/vapor distributors.