In this sulfur recovery unit(SRU),hydrogensulfide(H2S)is converted to elemental sulfurusing modified sulfur recovery unit.In the present study,first the simulation of Claus process has been considered using a process simulator called TSWEET, then the effect of H2S concentration,H2S/CO2 ratio and acid gas flow of AG splitter in three different concent rations of oxygen(in inputair into the unit)on the main burner temperature and sulfur recovery have been studied and compared.It is shown that temperature of the main burner increases up to maximum temperature increasing fraction of AG splitter flow to main burner then it is redced by asharpslope;this is true for all three concent rations of oxygen.However,if two other parameters(concentration of H2S and H2S/CO2 ratio)increase,temperature of main burner increases monotonically;this increase has different slopes depending on oxygen concentration in inputair.Also in this paper it is shown that recovery rate of sulfur increases up to a maximum value then decreases as H2S concent ration and H2S/CO2 ratio(in all three concentrations of oxygen) increase.If 70-85% acid gas feed are entered the main burner,more optimal sulfur recovery rate than other flows would be achieved.

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