(203d) Distillate Hydrotreater Fouling

Fouling in hydrodesulfurization units is common throughout the refining industry. Hydrotreater capacity utilization and asset availability can be reduced because of the sometimes significant impacts of equipment fouling. Equipment fouling can result in inefficient heat transfer, rate restrictions and equipment downtime. Hydrotreaters are prone to fouling at different stages of the process and due to several different fouling mechanisms.

Low sulfur fuel regulations have resulted in higher severity operations of both naphtha and distillate hydrotreaters. In addition, ever greater utilization and a need to run these units for longer periods of time between turnarounds is common throughout the industry. As distillate hydrotreaters are being pushed to greater sulfur removal efficiencies, higher activity catalysts and temperatures are being employed. These changes are resulting in an increased incidence of fouling issues in distillate hydrotreaters. This paper will review the causes of fouling in distillate hydrotreater units along with some of the possible solutions to these problems.