Recovery of elemental sulfur from sour gas

Process for recovery of sulfur from a gas stream containing hydrogen sulfide comprising:

• (a) combusting the gas stream in the presence of oxygen in a thermal reaction zone to produce hot combustion gases containing hydrogen sulfide, sulfur dioxide, and free sulfur;
• (b) cooling the hot combustion gases and condensing free sulfur therefrom to produce a first cool lean stream containing hydrogen sulfide and sulfur dioxide;
• (c) heating the first cool lean stream to a temperature above the dew point of sulfur in indirect heat exchange relation via a heat transfer medium with the hot combustion gases to produce a first heated lean stream;
• and
• (d) reacting hydrogen sulfide and sulfur dioxide in the first heated lean stream in a catalytic reaction zone to produce additional free sulfur, the catalytic reaction zone comprising at least one catalytic reactor operated above the dew point of sulfur.

Apparatus comprising:

• combustion means for combusting in the presence of oxygen a gas stream containing hydrogen sulfide to produce hot combustion gases containing hydrogen sulfide, sulfur dioxide, and free sulfur;
• first catalytic reactor means in flow communication with the combustion means for receiving and reacting at least a portion of said hydrogen sulfide and sulfur dioxide in the hot combustion gases for producing free sulfur, for adsorbing a preponderance of the thus produced free sulfur on catalyst therein and for producing a lean effluent stream;
• heat exchange means in indirect heat exchange relation via a heat transfer medium with the hot combustion gases for heating a cool gas stream in indirect heat exchange relation with the hot combustion gases to produce a hot regeneration stream having a temperature effective for removing sulfur adsorbed on the catalyst of said first catalytic reactor means;
• and
• regeneration and recovery means in flow communication with the heat exchange means for receiving and passing the hot regeneration stream in contact with the catalyst having free sulfur adsorbed thereon to remove free sulfur therefrom and for recovering the thus-removed free sulfur.

Apparatus for the recovery of sulfur comprising:

• combustion means for combusting a gas stream containing hydrogen sulfide to produce hot combustion gases containing hydrogen sulfide, sulfur dioxide, and free sulfur;
• first cooling means in flow communication with the combustion means for receiving and cooling the hot combustion gases and condensing free sulfur therefrom to produce a first cool stream;
• first heat exchange means in flow communication with the first cooling means for receiving and providing the first cool stream in indirect heat exchange relation via a heat transfer medium with the hot combustion gases for heating the first cool stream to a temperature above the dew point of sulfur;
• and first catalytic reactor means in flow communication with the first heat exchange means for receiving the thus heated stream therefrom and effective for reacting sulfur dioxide and hydrogen sulfide in the stream at a temperature above the dew point of sulfur to produce an effluent stream containing free sulfur.

Apparatus comprising:

• first catalytic reactor means and second catalytic reactor means for reacting hydrogen sulfide and sulfur dioxide in a feed stream and depositing a preponderance of the free sulfur thus produced on a catalyst bed in one of the first catalytic reactor means and the second catalytic reactor means;
• heat exchange means for heating a cool stream in indirect heat exchange relation via a heat transfer medium with hot combustion gases produced by combustion of hydrogen sulfide in the presence of oxygen to produce said hydrogen sulfide and sulfur dioxide in said feed stream to produce a regeneration steam;
• means for providing the feed stream in flow communication with one of the first catalytic reactor and the second catalytic reactor and for providing one of the cool stream and the regeneration stream in flow communication with the other of the first catalytic reactor means and the second catalytic reactor means;
• means in flow communication with the other of the first catalytic reactor means and the second catalytic reactor means for recovering free sulfur from an effluent stream from said other of the first catalytic reactor means and the second catalytic reactor means;
• and
• means in flow communication between the outlets of the first catalytic reactor and the second catalytic reactor for maintaining the outlets of first catalytic reactor means and the second catalytic reactor means at about equal pressures.