Process for the removal of soot from a sulfurous gas stream
In a process for the removal of soot from a sulfurous gas stream, a process gas containing O 2 and more than 500 ppm SO 2 and/or SO 3 together with soot is brought into contact with a VK type catalyst in a reactor, said catalyst comprising vanadium pentoxide (V 2 O 5 ), sulfur in the form of sulfate, pyrosulfate, tri- or tetrasulfate and one or more alkali metals, such as Na, K, Rb or Cs, on a porous carrier, preferably a silicon dioxide carrier.
1. A process for the removal of soot comprising >90 wt % C from a sulfurous gas stream, wherein a process gas containing O 2 and more than 500 ppm SO 2 and/or SO 3 and a soot concentration of >2 mg/Nm 3 /h is brought into contact with a catalyst in a reactor, said catalyst comprising vanadium pentoxide (V 2 O 5 ), sulfur in the form of sulfate, pyrosulfate, tri- or tetrasulfate and one or more alkali metals on a porous carrier.
2. Process according to claim 1 , wherein the porous carrier of the catalyst is silicon dioxide (SiO 2 ).
3. Process according to claim 2 , wherein the porous carrier of the catalyst is SiO 2 with <10 wt % of alumina.
4. Process according to claim 3 , wherein the porous carrier of the catalyst is SiO 2 with <2 wt % of alumina.
5. Process according to claim 3 , wherein the porous carrier of catalyst is SiO 2 with <1 wt % of alumina.
6. Process according to claim 1 , wherein the alkali metal content of the catalyst is 2-25 wt %.
7. Process according to claim 1 , wherein the catalyst contains 1-15 wt % V 2 O 5 .
8. Process according to claim 7 , wherein the catalyst contains 2-12 wt % V 2 O 5 .
9. Process according to claim 1 , wherein the catalyst contains 1-25 wt % sulfur in the form of sulfate, pyrosulfate, tri- or tetrasulfate.
10. Process according to claim 9 , wherein the catalyst contains 2-20 wt % sulfur in the form of sulfate, pyrosulfate, tri- or tetrasulfate.
11. Process according to claim 10 , wherein the catalyst contains 4-16 wt % sulfur in the form of sulfate, pyrosulfate, tri- or tetrasulfate.
12. Process according to claim 1 , wherein the catalyst temperature is 250-700° C.
13. Process according to claim 12 , wherein the catalyst temperature is 300-650° C.
14. Process according to claim 1 , wherein the process gas has a soot concentration of >5 mg/Nm 3 /h.
15. Process according to claim 14 , wherein the process gas has a soot concentration of >20 mg/Nm 3 /h.
16. Process according to claim 14 , wherein the process gas has a soot concentration of >50 mg/Nm 3 /h.
17. Process according to claim 1 , wherein the process gas contains more than 1000 ppm SO 2 and/or SO 3 .
18. Process according to claim 17 , wherein the process gas contains more than 5000 ppm SO 2 and/or SO 3 .
19. Process according to claim 1 , wherein the soot in the process gas has a composition comprising >95 wt % C.
20. Process according to claim 1 , wherein the soot is carbon black.
21. Process according to claim 1 , wherein the alkali metal content of the catalyst is 8-16 wt %.
22. Process according to claim 1 , wherein the process gas contains more than 2500 ppm SO 2 and/or SO 3 .