The contaminants of acid gas feed to the Claus process plants such as benzene, toluene, ethylbenzene, and xylene (BTEX) increase the operational cost through catalyst deactivation and high fuel gas consumption and impact the sulfur recovery efficiency and the emission of toxic gases (such as CO and SO2). In this study, a detailed and validated reaction mechanism for Claus feed combustion is utilized to simulate the Claus process plant by integrating Chemkin Pro and Aspen HYSYS software. The effect of oxygen enrichment of air on sulfur recovery, BTEX destruction, toxic gas emissions, and fuel gas consumption is studied. Upon increasing the oxygen concentration in air, BTEX concentration decreased substantially due to their enhanced oxidation by SO2 and O-2. An increase in oxygen concentration resulted in (a) increased SO2 emission and decreased CO2 emission from the incinerator, and (b) decreased fuel gas consumption in the incinerator. Interestingly, CO emission increased with increase in oxygen concentration in air as the furnace temperature increased up to 1350 degrees C, but it decreased with the further increase in the furnace temperature at higher oxygen concentrations. The reaction path analysis is presented to understand this decrease in CO emissions at high oxygen concentrations. The results demonstrate that a high oxygen concentration in air can be utilized to decrease fuel gas consumption and CO and CO2 emissions in the Claus process. The oxygen concentration, required to minimize the emission of aromatics, SO2, CO, and CO2, was dependent on the feed composition, and the developed reaction mechanism can assist in optimizing the oxygen enrichment level required for a given feed in a Claus process plant.