Separating sweet gas from a sour gas stream

1. An apparatus comprising:

a first pressure vessel for generating a sweet gas from a sour gas stream via an oxidation-reduction reaction that results in formation of surface foam and a non-gaseous multi-phase mixture comprising an emulsion, the first pressure vessel comprising:

a first inlet for receiving the sour gas stream;

a first outlet for outputting the sweet gas;

a primary stage phase separator comprising a second inlet disposed inside the first pressure vessel and a second outlet for outputting a separated non-gaseous multi-phase mixture, the second inlet located such that the surface foam and the separated non-gaseous multi-phase mixture flow into a partially gas-filled upper section of the primary stage phase separator and freefall to a lower level, thereby facilitating mechanical breaking of the surface foam and the emulsion; and

a secondary stage phase separator comprising a second pressure vessel, a third inlet connected to the first outlet of the first pressure vessel, a third outlet for the sweet gas, and a fourth outlet for non-gaseous multi-phase mixture surge.

2. The apparatus of claim 1 wherein the second inlet is located at a maximum level of the non-gaseous multi-phase mixture within the first pressure vessel.

3. The apparatus of claim 1 wherein a diameter of the first pressure vessel and a diameter of an orifice of the second inlet are in a ratio in a range of 2:1 to 5:1, inclusive.

4. The apparatus of claim 1 wherein the primary stage phase separator comprises a vertically-oriented pipe and the lower level is defined by a section of the vertically-oriented pipe that is filled with the separated non-gaseous multi-phase mixture.

5. The apparatus of claim 4 further comprising a valve that controls flow of the separated non-gaseous multi-phase mixture out of the primary stage phase separator.

6. The apparatus of claim 5 further comprising a controller that adjusts the valve to maintain the separated non-gaseous multi-phase mixture at a target level within the vertically-oriented pipe.

7. The apparatus of claim 1 wherein the primary stage phase separator comprises a vertically-oriented upper section, a vertically-oriented lower section, and a horizontally-oriented section that traverses a wall of the first pressure vessel and connects the upper section with the lower section, and wherein the lower level is defined by a portion of the vertically-oriented lower section that is filled with the separated non-gaseous multi-phase mixture.

8. The apparatus of claim 7 further comprising a valve that controls flow of the separated non-gaseous multi-phase mixture out of the primary stage phase separator.

9. The apparatus of claim 8 further comprising a controller that adjusts the valve to maintain the separated non-gaseous multi-phase mixture at a target level within the vertically-oriented lower section.

10. The apparatus of claim 1 further comprising a valve that controls flow of the non-gaseous multi-phase mixture surge out of the second pressure vessel.

11. The apparatus of claim 10 further comprising a controller that adjusts the valve to maintain the non-gaseous multi-phase mixture surge at a target level within the second pressure vessel.

12. An oxidation-reduction desulfurization system comprising:

a reactor vessel in which oxidation-reduction of a sour gas stream results in formation of surface foam, gas, and a non-gaseous multi-phase mixture comprising an emulsion, the reactor vessel having a diameter and comprising:

a first inlet for receiving the sour gas stream;

a first outlet for the gas;

a primary stage phase separator comprising a second inlet disposed inside the reactor vessel and a second outlet for the non-gaseous multi-phase mixture, the second inlet having a diameter and being located such that the surface foam and the non-gaseous multi-phase mixture flow into a partially gas-filled upper section of the primary stage phase separator and freefall to a lower level, thereby facilitating mechanical breaking of the foam and the emulsion, the diameter of the reactor vessel sized relative to the diameter of the second inlet in a ratio in a range of 2:1 to 5:1, inclusive; and

a secondary stage phase separator comprising a pressure vessel, a third inlet orifice connected to the first outlet, a third outlet for the gas, and a fourth outlet for non-gaseous multi-phase mixture surge.

13. The apparatus of claim 12 further comprising a first valve that controls flow of the non-gaseous multi-phase mixture out of the primary stage phase separator and a controller that adjusts the first valve to maintain the non-gaseous multi-phase mixture at a first target level within the primary stage phase separator.

14. The apparatus of claim 13 comprising a second valve that controls flow of the non-gaseous multi-phase mixture surge out of the secondary stage phase separator, and wherein the controller adjusts the second valve to maintain the non-gaseous multi-phase mixture surge at a second target level within the secondary stage phase separator.

15. The apparatus of claim 12 wherein the primary stage phase separator comprises a vertically-oriented pipe and the lower level is defined by a section of the vertically-oriented pipe that is filled with the non-gaseous multi-phase mixture.

16. The apparatus of claim 12 wherein the primary stage phase separator comprises a vertically-oriented upper section, a vertically-oriented lower section, and a horizontally-oriented section that traverses a wall of the reactor vessel and connects the upper section with the lower section, and wherein the lower level is defined by a portion of the vertically-oriented lower section that is filled with the non-gaseous multi-phase mixture.