Column Revamps: From Outside to Inside

Some of the many things to consider for the complex task of performing a column revamp are presented in this cover story Petroleum refineries, chemical-processing plants, natural-gas purification plants and other facilities in the chemical process industries (CPI) all contain columns. These columns perform distillations [1], regenerations, strippings and absorptions. Column diameters range from 12 in. to 50 ft, and column heights range from 10 to 350 ft. FIGURE 1. Revamping a column is a major undertaking[/caption] Prior to about 1970, the majority of the column work performed in the U.S. was the building and installation of new, grass roots, columns. Subsequent to that, the workload shifted, with many existing columns being revamped to achieve performance improvements or maintenance targets. When columns are revamped, some columns are revamped on the outside; some, on the inside (Figure 1); and some, both. Associated with columns are heat exchangers, reboilers, condensers, receivers, pumps, valves, tanks and instrumentation. Most column revamps necessarily include evaluations and modifications of this ancillary equipment. Unfortunately for us, no two real column revamps are identical. They are never easy. And column revamps…