Destruction of BTX present in Natural Gas Feedstock by Oxidation via Sulfur dioxide in Claus Process

Abstract

Claus process is one of the major catalytic processes used in the industry to recover
sulfur from H2S found in raw natural gas and from various gases from refinery. It has
two major sections: a). Claus Furnace, where non-catalytic partial oxidation of H2S
takes place, and b). Catalytic unit, where unburnt H2S and SO2 from the furnace
produce elemental sulfur. The H2S gas is followed by various contaminants, the
major one being Benzene, Toluene, and Xylene, collectively known as BTX, along with
compounds like NH3. These compounds are harmful and have a pernicious effect on
the catalytic reactors, with BTX being of the order of highest concern. BTX
collectively inhibit the catalyst activity by poisoning the catalyst, also forming sulfurhydrocarbons,
which are dangerous to the environment as a whole. BTX-radicals and
SO2 react to form intermediate species and then the reaction proceeds to
completion. Interaction between species and stability of the intermediate formed is
studied using the Density functional theory. Rates of elementary reactions involved
are studied using the transition state theory. Formation of important, and less malign
by-products such as CO, CO2, -CHO were studied and the reaction pathways leading
to the formation of these by-products were procured
In this article, emphasis is given to obliteration of BTX, by oxidation with SO2 as a
possible solution by placing a BTX obliteration unit between the Claus furnace and
Claus-catalytic unit so that it does not reach the catalytic unit and clog the catalyst.