Body (girth) flanges have
distinct advantages in small columns (Part 2)
As discussed in Part 1
, small-diameter columns are typically smaller than 36” diameter and present unique equipment design and installation challenges compared to larger columns.
Additional design advantages to using body flanges include:
Single-piece equipment construction is often more practical in flanged columns because of their smaller size and open cross-section, which allows complete equipment and structured packing layers to be delivered to the site and put in place with little or no additional assembly.
Internals do not need to be subdivided to pass through a manway with this approach, so they may be designed taller than a typical device in a larger column without using additional joints or seams. Taller designs can be used to increase the operating range or residence time of a device if needed, with no additional leakage.
Without internal tower attachments to restrict flow, more of a column’s cross-sectional area is available to distribute vapor and liquid through the internal equipment. This promotes better column performance by improving liquid distribution quality and preventing vapor dead zones in packed beds. Flange-mounted equipment also forms a liquid seal at the column wall that is equivalent to weld-in designs without actually welding.
Flanged columns do not require separate manways, and no space is needed in the column for installers. Practically, this means that the cost of manways can be eliminated and the overall column height can be shortened.
Read Part I
to learn more about body flanges and how the use of this design can enable unique construction and installation solutions.