ACTIVATED CARBON SORBENT COMPOSITION WITH REDUCED AUTO-IGNITION PROPERTIES
An activated carbon sorbent composition comprising activated carbon and a passivation agent, wherein the activated carbon sorbent composition exhibits reduced self-heating or auto-ignition properties as compared to the activated carbon. The activated carbon sorbent composition may be utilized to sequester contaminants such as mercury from a flue gas stream. The passivation agent includes a sulfur species, and may be a sulfur oxide compound, a sulfide compound, or an organic sulfur compound. Methods for the manufacture of the activated carbon sorbent composition and for the sequestration of contaminants in a flue gas stream using the composition are also disclosed.
1 . An activated carbon sorbent composition, comprising:
activated carbon; and
a passivation agent, the passivation agent comprising a sulfur oxide compound selected from the group consisting of:
(i) a nonionic sulfur oxide compound defined by the formula SO y , where y=2 or 3; and
(ii) an ionic sulfur oxide compound comprising an anion defined by the formula SO x O y 2− , where x=1 or 2 and y=2, 3, 4, 5, or 6.
2 . The sorbent composition recited in claim 1 , wherein the sulfur oxide compound is an ionic sulfur oxide compound.
3 . The sorbent composition recited in claim 2 , wherein the ionic sulfur oxide compound comprises a cation that is selected from the group consisting of hydrogen, a nitrogen-containing compound, and a metal cation.
4 . The sorbent composition recited in claim 3 , wherein the cation is hydrogen.
5 . The sorbent composition recited in claim 4 , wherein the ionic sulfur oxide compound is sulfuric acid.
6 . The sorbent composition recited in claim 3 , wherein the cation is a nitrogen-containing compound.
7 . The sorbent composition recited in claim 6 , wherein the nitrogen-containing compound is ammonium.
8 . The sorbent composition recited in claim 7 , wherein the ionic sulfur oxide compound is ammonium sulfate.
9 . The sorbent composition recited in claim 6 , wherein the nitrogen-containing compound is an alkylammonium compound.
10 . The sorbent composition recited in claim 3 , wherein the cation comprises a metal cation.
11 . The sorbent composition recited in claim 10 , wherein the metal cation is selected from the group consisting of an alkali metal, an alkaline earth metal and a transition metal.
12 . The sorbent composition recited in claim 11 , wherein the metal cation is an alkali metal.
13 . The sorbent composition recited in claim 12 , wherein the alkali metal cation is selected from the group consisting of lithium, sodium, and potassium.
14 . The sorbent composition recited in claim 13 , wherein the alkali metal is sodium.
15 . The sorbent composition recited in claim 11 , wherein the metal cation is an alkaline earth metal.
16 . The sorbent composition recited in claim 15 , wherein the alkaline earth metal is selected from the group consisting of magnesium, calcium, and barium.
17 . The sorbent composition recited in claim 11 , wherein the metal cation is a transition metal.
18 . The sorbent composition recited in claim 17 , wherein the transition metal is selected from the group consisting of zinc, iron, copper, nickel, titanium, manganese, aluminum, and vanadium.
19 . The sorbent composition recited in claim 18 , wherein the transition metal is selected from the group consisting of iron, aluminum, and zinc.
20 . (canceled)
21 . (canceled)
22 . The sorbent composition recited in claim 1 , wherein the sorbent composition comprises at least about 0.1 wt. % of the sulfur oxide compound.
23 . (canceled)
24 . (canceled)
25 . (canceled)
26 . The sorbent composition recited in claim 1 , wherein the sorbent composition comprises not greater than about 10 wt. % of the sulfur oxide compound.
27 . The sorbent composition recited in claim 1 , wherein the sorbent composition comprises not greater than about 5 wt. % of the sulfur oxide compound.
28 . (canceled)
29 . The sorbent composition recited in claim 1 , wherein the specific enthalpy of the sorbent composition is at least about 10% lower than the specific enthalpy of the activated carbon.
30 . (canceled)
31 . The sorbent composition recited in claim 1 , wherein the specific enthalpy of the sorbent composition is at least about 30% lower than the specific enthalpy of the activated carbon.
32 . (canceled)
33 . (canceled)
34 . The sorbent composition recited in claim 1 , wherein the peak oxidation rate of the sorbent composition is at least about 10% lower than the peak oxidation rate of the activated carbon.
35 . (canceled)
36 . The sorbent composition recited in claim 1 , wherein the peak oxidation rate of the sorbent composition is at least about 30% lower than the peak oxidation rate of the activated carbon.
37 . (canceled)
38 . The sorbent composition recited in claim 1 , wherein the peak oxidation rate of the sorbent composition is at least about 50% lower than the peak oxidation rate of the activated carbon.
39 . The sorbent composition recited in claim 1 , further comprising an oxidation agent.
40 . The sorbent composition recited in claim 39 , wherein the oxidation agent comprises a halogen species.
41 . (canceled)
42 . (canceled)
43 . The sorbent composition recited in claim 1 , wherein the activated carbon sorbent composition comprises substantially free-flowing particulates of powdered activated carbon.
44 . The sorbent composition recited in claim 43 , wherein the powdered activated carbon has a median particle size of not greater than about 20 μm.
45 . The sorbent composition recited in claim 43 , wherein the powdered activated carbon has a median particle size of at least about 6 μm.
46 . (canceled)
47 . The sorbent composition recited in claim 43 , wherein the powdered activated carbon has a median particle size of not greater than about 20 μm, a particle density of at least about 0.4 g/cc, and a total pore volume of at least about 0.2 cc/g.
48 . (canceled)
49 . The sorbent composition recited in claim 43 , wherein the powdered activated carbon has a median particle size of not greater than about 12 μm, a particle density of at least about 0.4 g/cc, and a total pore volume of at least about 0.2 cc/g.
50 . The sorbent composition recited in claim 1 , wherein the sulfur oxide compound is in the form of a coating on the activated carbon.
51 . The sorbent composition of claim 1 , wherein the sulfur oxide compound comprises sulfur oxide compound particulates that are admixed with the activated carbon.
52 - 88 . (canceled)