Removal of contaminants from gas streams
View Patent ↗A process for the removal of contaminants from a gas stream is disclosed. A gas stream is contacted with a chlorine-containing compound to form a mixed gas stream. The mixed gas stream is then contacted with a sorbent in a sorption zone to produce a product gas stream and a sulfur laden sorbent, wherein the sorbent comprises zinc and a promoter metal.
1. A process comprising;
a) contacting a gas stream comprising H 2 S with a chlorine-containing compound to form a mixed gas stream;
b) contacting said mixed gas stream with a sorbent in a sorption zone to produce a first product gas stream and a sulfur laden sorbent, wherein said sorbent comprises a zinc-containing compound, silica, and a promoter metal;
c) drying at least a portion of said sulfur-laden sorbent to thereby provide a dried sulfur-laden sorbent;
d) contacting at least a portion of said dried sulfur laden sorbent with a regeneration gas stream in a regeneration zone to produce a regenerated sorbent comprising a zinc-containing compound, a silicate, and a promoter metal, and an off-gas stream;
e) returning said regenerated sorbent to said sorption zone to provide a renewed sorbent comprising zinc, silica, and a promoter metal; and
f) contacting said renewed sorbent with said mixed gas stream in said sorption zone to form a second product gas stream and a sulfur laden sorbent.
2. A process in accordance with claim 1 wherein said promoter metal is nickel.
3. A process in accordance with claim 1 , wherein said sorbent comprises a substitutional solid metal solution characterized by the formula M A Zn B , wherein M is said promoter metal, wherein A and B are in the range of from about 0.01 to about 0.99.
4. A process in accordance with claim 1 , wherein said regenerated sorbent returned to said sorption zone in step (e) comprises a substitutional solid metal oxide solution characterized by the formula M X Zn Y O, wherein M is said promoter metal, wherein X and Y are in the range of from about 0.01 to about 0.99.
5. A process in accordance with claim 1 , wherein said gas stream comprises in the range of from about 0.001 to about 5 volume percent H 2 S.
6. A process in accordance with claim 1 , wherein said product gas stream comprises less than 50 ppmv H 2 S.
7. A process in accordance with claim 1 wherein said chlorine-containing compound is present in said mixed gas stream in an amount in the range of from about 1 ppmv to about 3 volume percent.
8. A process in accordance with claim 1 wherein said chlorine-containing compound is present in said mixed gas stream in an amount in the range of from about 50 ppmv to about 1 volume percent.
9. A process in accordance with claim 1 wherein said chlorine-containing compound is present in said mixed gas stream in an amount in the range of from 100 ppmv to 1000 ppmv.
10. A process in accordance with claim 1 wherein said gas stream further comprises compounds selected from the group consisting of carbon monoxide, hydrogen and combinations thereof.
11. A process in accordance with claim 1 wherein said sorbent is reduced with a reducing agent in a reduction zone prior to said contacting of said gas stream in step (a).
12. A process in accordance with claim 11 wherein said reducing agent comprises an agent selected from the group consisting of hydrogen and carbon monoxide.
13. A process in accordance with claim 1 wherein said gas stream further comprises a reducing agent.
14. A process in accordance with claim 13 wherein said reducing agent comprises an agent selected from the group consisting of hydrogen and carbon monoxide.
15. A process in accordance with claim 1 wherein conditions in said sorption zone include a temperature in the range of from about 150° C. to about 1000° C.
16. A process in accordance with claim 1 wherein conditions in said sorption zone include a temperature in the range of from about 250° C. to about 700° C.
17. A process in accordance with claim 1 wherein conditions in said sorption zone include a temperature in the range of from about 350° C. to about 550° C.
18. A process in accordance with claim 1 wherein conditions in said sorption zone include a pressure in the range of from about atmospheric pressure to about 5000 psig.
19. A process in accordance with claim 1 wherein conditions in said sorption zone include a pressure in the range of from about atmospheric pressure to about 1000 psig.
20. A process in accordance with claim 1 wherein conditions in said regeneration zone includes a regeneration gas stream.
21. A process in accordance with claim 20 wherein said regeneration gas stream comprises oxygen.
22. A process in accordance with claim 20 wherein said regeneration gas stream comprises air.
23. A process in accordance with claim 1 wherein said off-gas stream comprises H 2 S.
24. A process in accordance with claim 23 wherein said offgas stream is recycled to a SO 2 treatment zone.
25. A process in accordance with claim 24 wherein said SO 2 treatment zone comprises a Claus unit.