Thermodynamics of Claus conversion of reduced sulfur dioxide

Abstract

To the sustainable economic development it is necessity to provide the total utilization every kind the waste including sulphurous off-gases of non-ferrous metallurgy. For the distant metallurgical works the most acceptable way for the utilization of the “strong” sulfurous gases of autogenous smelting that contain of over than 20% sulfur dioxide is elemental sulfur production because sulfur in elemental form is commercial product that the most tailored for transportation or long-time storage. To estimate of the potential resources of the sulfur recovery from the sulfurous off-gases autogeneous smelting, in the temperature range 250÷1350 oС, the thermodynamics of the reduction by methan of oxygen-beared sulfurous gases containing ~36 % by volume SO2 is analyzed at a total pressure of 1.0 and 1.3 bar. As it is show the thermodynamics calculation results excess of reducing agent strongly diminishing of the sulfur yield in last stage of the catalytic Claus processing of a real reducted sulfurous gas. According to the results of thermodynamic calculations at 3000 oC and under Claus ratio CR≡[H2S]/[SO2]=0,36÷1,98, it is find that equilibrium concentration of hydrogen sulfide in reducted gas is increase by the Claus ratio increasing. Comparing of the thermodynamic analysis results with the factual data of the reducted sulfurous gases conversion at the temperature 230÷260 oС in the catalytic reactor of the Elemental Sulfur Production Site at Copper Plant of Nornickel’ Polar Division is made. It is determine that in acid gases processing in Claus reactors the real values of the hydrogen sulfide conversion substantially exceed equilibrium conversion values, that may be because limits of the rate of the sulfur hydrolysis reaction inverse of the Claus reaction and make urgent to develop of the kinetic model of the Claus conversion. As it is found by the industrial experimental data analysis, the optimize temperature for the stage of the reducted sulfurous gas Claus conversion is temperature of the Claus reactor 230–250 oC.