Tailgas Clean-up

An overview over the numerous processes by which Claus tailgases can be genuinely treated to reduce sulfur emissions is given in Fig. 5.12. It shows the products resulting from the various processes and the achievable residual contents (H2S + SO2). As a detailed description of all the processes would go far beyond the scope of this chapter, only two processes which are typical for their respective groups will be dealt with here in greater detail while the others will only be mentioned briefly. 

The LURGI Sulfreen Process is very similar to the Claus process and can be conveniently combined with it. Its major difference lies in the lower operating temperature which ensures that the sulfur recovered over the catalyst is simultaneously adsorbed by it. 

The Scot Process (SHELL Claus Off-gas Treating) developed by SHELL Internationale Maatschappij already in 1971 uses two steps  

The process arrangement is illustrated by Fig. 5.14. The tailgases leaving the Claus unit at temperatures around 140°C are heated to stnne 300 C by fuel gas combustion. As hydrogenation requires reducing gases, the fuel gas may 

Claus sulphur recovery with SCOT tailgas clean up 

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Desulfurization of fossil fuels was the subject of an authoritative review by J. B. Hyne (Alberta Sulphur Research Institute). This is a topic of increasing importance as Canada relies more and more on sulfur-containing fuels such as tar sands and heavy oils. Hyne reviewed the present state of the chemistry and technology for both precombustion desulfurization of natural gas and crude oils and postcombustion tailgas clean up of coals and cokes. He clearly identified areas of possible future research such as the high temperature-high pressure chemistry pertaining to in-situ desulfurization processes. 

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