An investigation of reaction furnace temperatures and sulfur recovery

In a modern day sulfur recovery unit(SRU),hydrogen sulfide(H_(2)S)is converted to elemental sulfur using a modified Claus unit.A process simulator called TSWEET has been used to consider the Claus process.The effect of the H_(2)S concentration,the H_(2)S/CO_(2) ratio,the input airflow rate,the acid gasflow of the acid gas(AG)splitter and the temperature of the acid gas feed at three different oxygen concentrations(in the air input)on the main burner temperature have been studied.Also the effects of the tail gas ratio and the catalytic bed type on the sulfur recovery were studied.The bed temperatures were optimized in order to enhance the sulfur recovery for a given acid gas feed and air input.Initially when the fraction of AG splitterflow to the main burner was increased,the temperature of the main burner increased to a maximum but then decreased sharply when theflow fraction was further increased;this was true for all three concentrations of oxygen.However,if three other parameters(the concentration of H_(2)S,the ratio H_(2)S/CO_(2) and theflow rate of air)were increased,the temperature of the main burner increased monotonically.This increase had differ-ent slopes depending on the oxygen concentration in the input air.But,by increasing the temperature of the acid gas feed,the temperature of the main burner decreased.In general,the concentration of oxygen in the input air into the Claus unit had little effect on the temperature of the main burner(This is true for all parameters).The optimal catalytic bed temperature,tail gas ratio and type of catalytic bed were also determined and these conditions are a minimum temperature of 300°C,a ratio of 2.0 and a hydrolysing Claus bed.