Root Cause Study of Debutanizer Column Operational Upsets

The NOVA Chemicals Debutanizer Column at the Corunna site experienced operational upsets. Gamma scans revealed that the column had flooded, and upon opening the tower it was found that the bottom trays fouled. An investigation was initiated to identify the root causes of fouling as well as optimized conditions under which fouling is minimized. Fouling deposit samples were collected at different times and characterized employing various analytical tests. Laboratory fouling experiments were designed and carried out to test fouling propensity of the tower bottom streams. In addition, experiments were run under different conditions to see how process variables such as temperature and residence time impact the debutanizer bottom fouling rates. A range of temperature and residence time conditions were identified under which fouling might be minimized.