Benzene destruction in Claus process by sulphur dioxide: a reaction kinetics study

S. Sinha, A. Raj, A. Al Shoaibi, S. Alhassan, S.H. Chung
Industrial & Engineering Chemistry Research, 53, pp. 10608-10617, (2014)

Benzene destruction in Claus process by sulphur dioxide: a reaction kinetics study

Keywords

Benzene, Toluene , Xylene,

Abstract

Benzene, toluene and xylene (BTX) are present as contaminants in the H2S gas stream entering a Claus furnace. The exhaust gases from the furnace enter catalytic units, where BTX form soot particles. These particles clog and deactivate the catalysts. A solution to this problem is BTX oxidation before the gases enter catalyst beds. This work presents a theoretical investigation on benzene oxidation by SO2. Density functional theory is used to develop a detailed mechanism for phenyl radical −SO2 interactions. The mechanism begins with SO2 addition to phenyl radical after overcoming an energy barrier of 6.4 kJ/mol. This addition reaction is highly exothermic, where a reaction energy of 182 kJ/mol is released. The most favorable pathway involves O–S bond breakage, leading to the release of SO. A remarkable similarity between the pathways for phenyl radical oxidation by O2 and its oxidation by SO2 is observed. The reaction rate constants are also evaluated to facilitate process simulations.

Code

DOI: 10.1021/ie501732a

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