Novel Sulfur Recovery Techniques for Oil and Gas Industries

In January 2007, Iran with 974 TCF natural gas reserves (around 16% of the global reserves) has occupied the second place after Russia. Most of these gases are referred to as "sour gas" because they are contaminated with hydrogen sulfide. Because of that, the production of elemental sulfur from hydrogen sulfide has a great role in Iranian natural gas industry. Unfortunately, all existing sulfur recovery units (SRUs) or even the new ones constructed in Assalouye industrial zone are using the old "Claus" process. Such processes, although using relatively expensive catalysts, they have low recovery efficiency (97%) and will eventually contaminate the environment. in this article, some novel technologies based on biotechnology (via microorganisms) and thermal decomposition of hydrogen sulfide (known as thermolysis) have been considered for sulfur recovery units. The techno-economical aspects of the latter process have been investigated in more details. In this process, the hydrogen sulfide is directly dissociated to hydrogen and elemental sulfur at elevated temperature and in the presence of appropriate catalyst. Hydrogen is then separated from other gases (hydrogen sulfide, sulfur and feed impurities), using a special membrane reactor. Only small amount of sulfure is then exhausted to atmosphere as sulfur dioxide due to superb efficiency (99.4%) of the thermolysis process. Furthermore, the produced hydrogen can also be used as a valuable raw material in petrochemical industry (such as methanol or ammonia productions) or as a clean and environment friendly fuel for automobiles.