Saudi Aramco eliminates aromatics-induced Claus catalyst deactivation using activated carbon

Saudi Aramco, like other operators with lean feed acid gas containing benzene, toluene and xylene (BTX,) has dealt for years with chronic Claus catalyst deactivation, low sulphur recovery and frequent shut-downs to replace catalyst. After completing an exhaustive process selection study to identify the most cost-effective solution to the problem, the company proceeded with installation of regenerable activated carbon beds upstream of the sulphur recovery units (SRUs) to remove aromatics contaminants before they reach the converter beds. Saudi Aramco completed construction of seven BTX removal units to treat acid feeding downstream sulphur plants in December 2005. Commissioning took place in the spring of 2006. This paper discusses design issues, start-up and commissioning experience for the units, their performance and impact on the downstream Claus catalyst. In brief, catalyst deactivation has been virtually eliminated. This has set the foundation to allow us to revamp the units to achieve higher recovery, which would not have been possible until the catalyst deactivation issue had been resolved.