Method for treating a flue gas stream with a sorbent composition having pneumatic conveyance capabilities
View Patent ↗Sorbent compositions including sorbent particles of a small particle sized sorbent with increased pneumatic conveyance properties. The sorbent compositions have relatively small median particle size and have a controlled particle size distribution (PSD). Specifically, the sorbent compositions include a relatively small percentage of very fine particles, such as a small percentage of particles having a particle size of not greater than about 5 μm. The sorbent compositions are particularly useful for the treatment of a flue gas stream to remove mercury from the flue gas stream.
1. A method for the treatment of a flue gas stream emanating from a boiler, comprising the step of contacting the flue gas stream with a particulate sorbent composition, the particulate sorbent composition comprising porous carbonaceous particles, wherein the particulate sorbent composition has a median particle size of not greater than about 20 μm, and a particle size distribution wherein not greater than about 10 vol. % of particles comprising the particulate sorbent composition have a particle size of not greater than about 5 μm.
2. The method recited in claim 1 , wherein the particulate sorbent composition has a median particle size of not greater than about 15 μm.
3. The method recited in claim 1 , wherein the particulate sorbent composition has a median particle size of not greater than about 12 μm.
4. The method recited in claim 1 , wherein not greater than about 5 vol. % of the particles comprising the particulate sorbent composition have a particle size of not greater than about 5 μm.
5. The method recited in claim 1 , wherein not greater than about 8 vol. % of the particles comprising the particulate sorbent composition have a particle size of not greater than about 3 μm.
6. The method recited in claim 1 , wherein not greater than about 5 vol. % of the particles comprising the particulate sorbent composition have a particle size of not greater than about 2 μm.
7. The method recited in claim 1 , wherein not greater than about 2 vol. % of the particles comprising the particulate sorbent composition have a particle size of not greater than about 1 μm.
8. The method recited in claim 1 , wherein the porous carbonaceous particles comprise powdered activated carbon.
9. The method recited in claim 1 , wherein the particulate sorbent composition has a Basic Flow Energy of at least about 300 mJ.
10. The method recited in claim 1 , wherein the particulate sorbent composition has a Basic Flow Energy of at least about 400 mJ.
11. The method recited in claim 1 , wherein the particulate sorbent composition has a Specific Energy of at least about 6 mJ/g.
12. The method recited in claim 1 , wherein the particulate sorbent composition has an Aeration Energy of not greater than about 54 mJ.
13. The method recited in claim 1 , wherein the particulate sorbent composition has an Aeration Ratio of at least about 9.
14. The method recited in claim 1 , wherein the particulate sorbent composition has an Aeration Ratio of at least about 30.
15. The method recited in claim 1 , wherein the particulate sorbent composition has a Conditioned Bulk Density of at least about 0.4 g/ml.
16. The method recited in claim 1 , wherein the particulate sorbent composition has a pressure drop as measured by the Permeability test of not greater than about 55 mbar at an applied normal stress of 15 kPa and at an air velocity of 0.5 mm/s.
17. The method recited in claim 1 , wherein the particulate sorbent composition has a pressure drop as measured by the Permeability test of not greater than about 25 mbar at an applied normal stress of 15 kPa and at an air velocity of 0.5 mm/s.
18. The method recited in claim 1 , wherein the particulate sorbent composition has a Compressibility of not greater than about 24% at an applied normal stress of 15 kPa.
19. The method recited in claim 1 , wherein the particulate sorbent composition has a Compressibility of not greater than about 14% at an applied normal stress of 15 kPa.
20. The method recited in claim 1 , wherein the contacting step comprises injecting the particulate sorbent composition into the flue gas stream.
21. The method recited in claim 1 , further comprising the step transporting the sorbent composition from a storage facility to the contacting step, wherein the transporting step comprises pneumatically conveying the particulate sorbent composition.
22. The method recited in claim 1 , wherein the flue gas stream comprises mercury and wherein the porous carbonaceous particles capture at least a portion of the mercury from the flue gas stream.
23. The method recited in claim 22 , wherein the flue gas stream comprises from about 1 ppbw to 100 ppbw mercury.
24. The method recited in claim 1 , wherein the sorbent composition further comprises an oxidizing agent.
25. The method recited in claim 24 , wherein the oxidizing agent comprises a halogen salt.