Methods for producing multifunctional catalysts for upgrading pyrolysis oil
A method of making a multifunctional catalyst for upgrading pyrolysis oil includes contacting a zeolite support with a solution including at least a first metal catalyst precursor and a second metal catalyst precursor, the first metal catalyst precursor, the second metal catalyst precursor, or both, including a heteropolyacid. Contacting the zeolite support with the solution deposits or adsorbs the first metal catalyst precursor and the second catalyst precursor onto outer surfaces and pore surfaces of the zeolite support to produce a multifunctional catalyst precursor. The method further includes removing excess solution from the multifunctional catalyst precursor and calcining the multifunctional catalyst precursor to produce the multifunctional catalyst comprising at least a first metal catalyst and a second metal catalyst deposited on the outer surfaces and pore surfaces of the zeolite support.
1. A method for upgrading pyrolysis oil, the method comprising:
contacting the pyrolysis oil with a multifunctional catalyst at mild reaction conditions comprising reaction temperatures of less than 500 degrees Celsius (° C.) and pressures less than 6 megapascals (MPa) where:
the pyrolysis oil is a bottom stream from a steam cracking process and comprises multi-ring aromatic compounds;
the multifunctional catalyst is produced by a process comprising:
contacting a zeolite support with a solution comprising at least a first metal catalyst precursor and a second metal catalyst precursor, the first metal catalyst precursor, the second metal catalyst precursor, or both, comprising a heteropolyacid that includes a heteroatom selected from the group consisting of phosphorous, silicon, germanium, arsenic, and combinations of these, where the contacting causes the first metal catalyst precursor and the second metal catalyst precursor to deposit onto outer surfaces and pore surfaces of the zeolite support to produce a multifunctional catalyst precursor;
removing excess solution from the multifunctional catalyst precursor; and
calcining the multifunctional catalyst precursor to produce the multifunctional catalyst;
where the multifunctional catalyst comprises at least a first metal catalyst and a second metal catalyst supported on the zeolite support
where contact of the pyrolysis oil with the multifunctional catalyst at the reaction conditions converts at least a portion of the multi-ring aromatic compounds in the pyrolysis oil to one or more C6-C8 aromatic compounds.
2. The method of claim 1 , in which the C6-C8 aromatic compounds include one or more of benzene, toluene, ethylbenzene, xylene, or combinations of these.
3. The method of claim 1 , in which contacting the pyrolysis oil with the multifunctional catalyst at the reaction conditions converts the portion of the multi-ring aromatic compounds in the pyrolysis oil to C6-C8 aromatic compounds in a single step, without conducting a subsequent chemical reaction step.
4. The method of claim 1 , in which the pyrolysis oil is contacted with the multifunctional catalyst at a temperature of from 300° C. to 450° C.
5. The method of claim 1 , in which the pyrolysis oil is contacted with the multifunctional catalyst at a pressure of from 0.1 MPa to 5 MPa.
6. The method of claim 1 , where the pyrolysis oil comprises greater than or equal to 50 weight percent multi-aromatic compounds.
7. The method of claim 1 , where the first metal catalyst precursor, the second metal catalyst precursor, or both have a Keggin structure having general formula XM 12 O 40 n− or a Dawson structure having the general formula XM 18 O 82 n− , in which X is the heteroatom; M is the molybdenum and optionally one or more of colbalt, vanadium, or a combination of these; and n− is an integer indicative of the charge of the anion of the heteropolyacid.
8. The method of claim 1 , where the solution includes from 1 wt. % to 20 wt. % of the first metal catalyst precursor and from 1 wt. % to 20 wt. % of the second metal catalyst precursor.
9. The method of claim 1 , where the first metal of the first metal precursor is a metal selected from the group consisting of molybdenum, vanadium, and cobalt and the first metal is different from the second metal of the second metal precursor.
10. The method of claim 1 , where the second metal of the second metal precursor is a metal selected from the group consisting of molybdenum, vanadium, and cobalt and wherein the second metal is different from the first metal of the first metal precursor.