Fluidization enhancers for the oxidative dehydrogenation of hydrocarbons
A process for oxidative dehydrogenation of a hydrocarbon to produce an olefin and water may include contacting, in a fluidized bed, the hydrocarbon with a particulate material, which may include at least one oxygen transfer agent (OTA) and at least one fluidization enhancing additive. During at least a portion of contacting the hydrocarbon with the particulate material, the fluidized bed may be at a temperature at or above a melting point of one or more materials of the oxygen transfer agent. Further, during at least a portion of contacting the hydrocarbon with the particulate material, a surface of at least a portion of the OTA may comprise a molten layer. The fluidization enhancing additive may not undergo reduction in the fluidized bed during contacting the hydrocarbon with the particulate material and may be present in an amount that maintains sufficient fluidization of the particulate material.
1. A process for dehydrogenation of a hydrocarbon to produce an olefin and water, the process comprising:
contacting, in a fluidized bed, the hydrocarbon with a particulate material consisting of:
an oxygen transfer agent; and
a fluidization enhancing additive consisting of inorganic materials;
wherein:
during at least a portion of the time of the contacting of the hydrocarbon with the particulate material, the fluidized bed is at a temperature at or above a melting point of one or more materials of the oxygen transfer agent;
during at least a portion of the time of the contacting of the hydrocarbon with the particulate material, a surface of at least a portion of the oxygen transfer agent is exposed to a temperature near or greater than the melting point of the material of the oxygen transfer agent such that at least a portion of the oxygen transfer agent comprises a molten layer;
the fluidization enhancing additive does not undergo reduction in the fluidized bed during the contacting of the hydrocarbon with the particulate material at the temperature;
the fluidization enhancing additive is present in an amount that maintains sufficient fluidization of the particulate material; and
the oxygen transfer agent and the fluidization enhancing additive are separate particles in the particulate material.
2. The process of claim 1 , wherein the oxygen transfer agent comprises a compound that undergoes reduction during the dehydrogenation thereby providing oxygen for formation of the water.
3. The process of claim 1 , wherein the oxygen transfer agent is a mixed oxide comprising Mg 6 MnO 8 .
4. The process of claim 3 , wherein the oxygen transfer agent further comprises at least two promoters comprising tungsten and an alkali metal, an alkaline earth metal, or a combination of the alkali metal and the alkaline earth metal.
5. The process of claim 1 , wherein the oxygen transfer agent comprises:
at least one reducible metal-containing oxide selected from the group consisting of manganese oxide, tin oxide, indium oxide, germanium oxide, lead oxide, antimony oxide, bismuth oxide, praseodymium oxide, terbium oxide, cerium oxide, iron oxide, ruthenium oxide, and a combination of two or more thereof;
at least one alkali metal species, said alkali metal species comprising elemental alkali metal or a compound comprising the alkali metal;
at least one boron-containing species, said boron-containing species comprising elemental boron or a compound comprising boron; and
at least one alkaline earth metal-containing species, said alkaline earth metal-containing species comprising elemental alkaline earth metal or a compound comprising alkaline earth metal.
6. The process of claim 5 , wherein the oxygen transfer agent comprises a mixed oxide of formula (1):
ML a B b C c O x (1)
where
M is selected from the group consisting of manganese, tin, indium, germanium, lead, antimony, bismuth, praseodymium, terbium, cerium, iron, ruthenium, and a combination of two or more thereof;
L is at least one alkali metal;
B is boron;
C is at least one alkaline earth metal;
O is oxygen;
a is from 0.01 to 10;
b is from 0.1 to 20;
c is from 0.1 to 100; and
x is a number of oxygen atoms required due to valence states of M, L, B, and C.
7. The process of claim 5 , wherein the oxygen transfer agent comprises a mixed oxide of formula (2):
MB b C c O x (2)
where
M is selected from the group consisting of manganese, tin, indium, germanium, lead, antimony, bismuth, praseodymium, terbium, cerium, iron, ruthenium, and a combination of two or more thereof;
B is boron;
C is at least one alkaline earth metal;
O is oxygen;
a is from 0.01 to 10;
b is from 0.1 to 20;
c is from 0.1 to 100; and
x is a number of oxygen atoms required due to valence states of M, L, B, and C.
8. The process of claim 1 , wherein the oxygen transfer agent is perovskite.
9. The process of claim 1 , wherein during at least a portion of the time of the contacting of the hydrocarbon with the particulate material, the fluidized bed is at a temperature from 650° C. to 1500° C.
10. The process of claim 1 , wherein the fluidization enhancing additive is selected from the group consisting of non-reducible oxides, zeolites, clays, fluid catalytic cracking catalysts, and combinations of two or more thereof.
11. The process of claim 1 , wherein the fluidization enhancing additive comprises a non-reducible oxide comprising an inorganic material comprising a chemical species selected from the group consisting of alumina, silica, silicon carbide, metal carbide, metal nitride, titanium dioxide, alkaline earth metal oxide, alkali sulfate, alkaline earth sulfate, calcium sulfate, hydrates of calcium sulfate, alkali carbonate, alkaline earth carbonate, boric acid, salts of boric acid, boric oxide, zinc oxide, cerium oxide, gallium oxide, and a combination of two or more thereof.
12. The process of claim 1 , wherein the fluidization enhancing additive comprises at least one zeolite of formula (3):
M 2/n O·Al 2 O 3 ·y SiO 2 ·w H 2 O (3)
where
y is an integer from 2 to 1,000,000,000;
n is a valence of a cationic portion of the at least one zeolite of formula (3);
M is a metal selected from the group consisting of Zr, Mg, Ti, and a combination of two or more thereof; and
w is a number of water molecules per zeolite unit structure, such that at least 5% of n is due to proton charge.
13. The process of claim 1 , wherein the fluidization enhancing additive comprises at least one fluid catalytic cracking catalyst.
14. The process of claim 13 , wherein the at least one fluid catalytic cracking catalyst is stabilized by addition of one or more additives.
15. The process of claim 1 , wherein a weight ratio of the oxygen transfer agent to the fluidization enhancing additive is from 50:50 to 99:1.
16. The process of claim 1 , wherein the oxygen transfer agent comprises:
an alkali metal and at least one of a mixed oxide of at least one metal that, when contacted with a hydrocarbon, is capable of oxidizing the hydrocarbon to a more unsaturated state or that couples carbon-carbon bonds with the formation of water as in reaction scheme (1):
z C n H 2n+2-2β +(z−1+δ)[O]→C z×n H 2(z×n)+2−2β−2δ +( z −1+δ)H 2 O (1)
where z equals the number of reacting paraffin molecules, n equals the number of atomic units in the reacting molecule, β equals the degree of unsaturation where the value is zero for single bonds, one for double bonds and molecular rings, and two for triple bonds, and 8 equals the change in the degree of unsaturation; and
a mixed oxide of at least one metal that, when contacted with hydrogen, is capable of hydrogen oxidation.
17. The process of claim 1 , wherein a weight ratio of the oxygen transfer agent to the fluidization enhancing additive is from 60:40 to 99:1.
18. The process of claim 1 , wherein a weight ratio of the oxygen transfer agent to the fluidization enhancing additive is from 70:30 to 99:1.
19. The process of claim 1 , wherein fluidization in the fluidized bed refers to gas-solid flow regimes chosen from expanded bed, minimum fluidization, smooth fluidization, bubbling fluidization, slugging fluidization, a turbulent fluidization, dense phase fluidization, spouting bed fluidization, channeling, lean phase fluidization, fast fluidization, or dilute transport fluidization.
20. A process for dehydrogenation of a hydrocarbon to produce an olefin and water, the process comprising:
contacting, in a fluidized bed, the hydrocarbon with a particulate material consisting of:
an oxygen transfer agent; and
a fluidization enhancing additive consisting of inorganic materials;
wherein:
the fluidization enhancing additive comprises:
at least one fluid catalytic cracking catalyst;
at least one zeolite of formula (3):
M 2/n O·Al 2 O 3 ·y SiO 2 ·w H 2 O (3)
where:
y is an integer from 2 to 1,000,000,000;
n is a valence of a cationic portion of the at least one zeolite of formula (3);
M is a metal selected from the group consisting of Zr, Mg, Ti, and a combination of two or more thereof; and
w is a number of water molecules per zeolite unit structure, such that at least 5% of n is due to proton charge;
or both;
during at least a portion of the time of the contacting of the hydrocarbon with the particulate material, the fluidized bed is at a temperature at or above a melting point of one or more materials of the oxygen transfer agent;
during at least a portion of the time of the contacting of the hydrocarbon with the particulate material, a surface of at least a portion of the oxygen transfer agent is exposed to a temperature near or greater than the melting point of the material of the oxygen transfer agent such that at a least portion of the oxygen transfer agent comprises a molten layer;
the fluidization enhancing additive does not undergo reduction in the fluidized bed during the contacting of the hydrocarbon with the particulate material at the temperature;
the fluidization enhancing additive is present in an amount that maintains sufficient fluidization of the particulate material; and
a weight ratio of the oxygen transfer agent to the fluidization enhancing additive is from 60:40 to 99:1.