Minimum downtime, maximum sulfur recovery Online Replacement of SUPERCLAUS~® Catalyst at the EnCana Sexsmith Gas Plant

摘要

The EnCana Sexsmith Gas Plant is a medium sized sour gas plant. The plant has one single SRU train using a conventional three stage Claus process for sulfur recovery and the SUPERCLAUS~® process for treating the Claus tail gas.rnIn the winter of 2005, the SUPERCLAUS~® catalyst experienced high temperatures as a result of the SUPERCLAUS~® converter bypass valve actuator failing. Up to this point, the plant had used its original catalyst charge from 1995. The catalyst was changed because of the questioned reliability of the catalyst after a temperature excursion causing the SUPERCLAUS~® catalyst to exceed temperatures of 740°C. An expected increase of raw inlet gas emphasized the need for reliable high sulfur recovery efficiencies in the SRU.rnThe catalyst change-out was unconventional in the aspect that the three stage Claus unit was online while the catalyst was being changed out. This minimized downtime and production loss. This paper will outline the root cause of the valve failing, the planning and execution of the change out and the economic and environmental benefits of changing the catalyst without a full shutdown. As a licensor of the SUPERCLAUS~® technology, Jacobs assisted EnCana with the planning and execution of the catalyst change out. Compared to other SUPERCLAUS~® start-ups, this start-up had an extra challenge with EnCana's objective to avoid any SO_2 emission violations during the complete turnaround and start-up period.rnAll together, proper preparation and planning resulted in a very quick turnaround that was executed within the scheduled time frame. Within seven days of the SUPERCLAUS~® start-up sulphur recovery efficiencies higher than 99.1% were obtained and the SRU was fully on-line again. During the complete turnaround and start-up period of two weeks, no SO2 emission violations were recorded. Furthermore, the plant has been running for 8 months with an overall sulfur recovery efficiency of 99.1% - 99.3%. Therefore, replacement of the SUPERCLAUS~® catalyst at the EnCana Sexsmith plant was determined to be a success.