Column Modification and Hardware

Another approach is to cut the existing column shell into two pieces (top and bottom sections), and then weld the prefabricated new middle section in, which increases the total number of trays. By carrying out this approach, energy can be reduced not only from the effect of the DWC but also the effect of an increase in the number of trays. Note that the heat losses from the shell and heat transfer across the dividing wall can be ignored in most cases. 

In the case that the middle section is still used and the optimized feed and side streams are different from the existing SSC s, consideration should be given to keeping their 

These different types of internal reflux splitters have to be chosen depending on the specific retrofit case, based on their features listed in Table 9.1. 

Splitter type Operating window/Control Reliability/Maintenance Cost/Structure 

Moving-bucket type Manual type In-the-column type Wide/Continuous Narrow/Discrete Narrow/Discrete Fair/Overhaul needed Excellent/Regular inspection Excellent/Regular inspection High/Complex Moderate/Simple Low/Simple 

---