ABSTRACT

The absence of efficient and reliable processes for natural gas deep desulphurization has aimed the search of new catalysts-adsorbents able to convert all the sulfur containing compounds and adsorb the H2S generated during desulphurization reactions. New applications of natural gas require the elimination of sulfur below the 0.1 threshold (as total sulfur).
The main purpose of the present doctoral thesis is to approach the problem of natural gas deep desulphurization to levels unsatisfied by conventional processes. The use of high throughput methodologies for catalytic tests, allowed to develop and optimize a new formulation of catalyst-adsorbent very active in desulphurization of thiophene, DMS and COS as well as with a high H2S adsorption capacity. The practical application has been evaluated by the study of side reactions which represent potential risks in plant operation because of their high exothermicity.
The use of catalysts based on Ni as active metal plus suitable promoters supported on a ZnAl mixed oxide derived from the thermal treatment of a hydrotalcite type material, allows to converting sulfur containing compounds present in natural gas to very high levels. The stability of this material has been checked by long term experiments (15 days TOS). The ease in preparation and processing, low raw material cost and high performance have allowed the raising of a new commercial product.