Process to produce sulphur from two acid gases, both containing hydrogen sulphide and one of which contains ammonia

In a process for producing sulfur from two hydrogen sulfide containing gas streams, one of said gas streams containing ammonia, wherein said gas streams are subjected to a heat-reaction step followed by an indirect gas-cooling step and at least one catalytic reaction step, the improvement which comprises a heat reaction which comprises:

• (a) burning the ammonia containing gas stream to form a first combustion mixture in a first heat-reaction chamber with air introduced into the first heat-reaction chamber, wherein the quantity of air is such that the ratio .rho., of the quantity of air injected into the first heat-reaction chamber to the quantity of air theoretically required for the total combustion of the hydrogen sulfide and ammonia to sulfur dioxide and nitrogen respectively, in said first heat-reaction chamber is between 0.7 and 1 and the temperature of the gases in said first heat-reaction chamber is maintained between 1350.degree. and 1550.degree. C.;
• (b) passing said first combustion mixture to a second heat-reaction chamber;
• (c) burning the gas stream free of ammonia in said second heat-reaction chamber in an amount in which the molar flow-rate of hydrogen sulfide in said second gas stream entering the second heat-reaction chamber is at least twice the molar flow-rate of hydrogen sulfide in the ammonia containing gas stream entering the first heat-reaction chamber, with a quantity of air sufficient to provide a molar ratio of H.sub.2 S/SO.sub.2 in the gas mixture leaving said heat-reaction chamber of about 2/1 and maintaining the temperature of the gases in the second heat-reaction chamber between 1000.degree. and 1500.degree. C.

In a process for producing sulfur from two hydrogen sulfide containing gas streams, one of said gas streams containing ammonia, wherein said gas streams are subjected to a heat-reaction step, by combustion with air, followed by an indirect gas-cooling step and at least one catalytic reaction step, the improvement which comprises, a heat reaction which comprises:

• (a) preheating the ammonia containing gas stream and air to a temperature of 150.degree. to 250.degree. C.;
• (b) burning the preheated ammonia containing gas stream to form a first combustion mixture, in a first heat-reaction chamber, with a quantity of said preheated air introduced into the first heat-reaction chamber such that the ratio .rho., of the quantity of air injected into the first heat-reaction chamber to the quantity of air theoretically required for the total combustion of the hydrogen sulfide and ammonia to sulfur dioxide and nitrogen respectively, in said first heat-reaction chamber is between 0.4 and 0.7 and maintaining the temperature of the gases in said first heat-reaction chamber between 1350.degree. and 1550.degree. C.;
• (c) passing said first combustion mixture to a second heat-reaction chamber;
• (d) burning the gas stream free of ammonia in said second heat-reaction chamber in an amount in which the molar flow-rate of hydrogen sulfide in said second gas stream entering the second heat-reaction chamber, is less than twice the molar flow-rate of hydrogen sulfide in the ammonia containing gas stream entering the first heat-reaction chamber, with a quantity of air sufficient to provide a molar ratio of H.sub.2 S/SO.sub.2 in the gas mixture leaving said heat reaction chamber of about 2/1 and maintaining the temperature of the gases in the second heat reaction chamber between 1000.degree. and 1500.degree. C.