Dual functional composite catalyst for olefin metathesis and cracking
Composite catalysts includes zeolite particles at least partially embedded in a catalyst support material and at least one catalytically active compound deposited on the outer surfaces and pore surfaces of the catalyst support material, zeolite particles, or both. A method of making the composite catalysts may include preparing a catalyst precursor mixture that includes the zeolite, catalyst support material, triblock copolymer surfactant, and the catalytically active compound precursor and spray drying the catalyst precursor mixture. The composite catalysts may be used as a single catalyst for conducting olefin metathesis and cracking reactions. A method for producing propene may include contacting a butene-containing feed with the composite catalysts.
1. A method of preparing a composite catalyst for use in isomerization, metathesis, and cracking reactions, the method comprising:
combining a catalyst support material, zeolite particles, a triblock copolymer surfactant, a catalytically active compound precursor, and a diluent to produce a catalyst precursor composition;
mixing the catalyst precursor composition to produce a catalyst precursor mixture in which the catalyst support material and the zeolite particles are suspended in the diluent; and
spray drying the catalyst precursor mixture, where spray drying comprises:
atomizing the catalyst precursor mixture to produce a plurality of droplets; and
drying the plurality of droplets in a drying chamber, where drying removes the diluent from each of the plurality of droplets to form agglomerates comprising the zeolite particles at least partially secured within the catalyst support material and causes the catalytically active compound precursor to react to form a catalytically active compound deposited on outer surfaces and pore surfaces of the catalyst support material, the zeolite particles, or both.
2. The method of claim 1 in which the catalyst support material comprises solid particles comprising at least one of silica, fumed silica, alumina, fumed alumina, titania, fumed titania, or combinations of these.
3. The method of claim 1 in which the zeolite particles comprise a mordenite framework inverted structured zeolite.
4. The method of claim 1 where the zeolite particles comprise ZSM-5 zeolite.
5. The method of claim 1 , in which the zeolite particles have an average particle size of from 5 micrometers to 35 micrometers.
6. The method of claim 1 in which the triblock copolymer surfactant is poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol).
7. The method of claim 1 comprising mixing the catalyst precursor composition for a period of time sufficient to produce a stable catalyst precursor mixture.
8. The method of claim 1 in which the combining comprises preparing a first mixture, a second mixture, and a third mixture, where:
the first mixture comprises:
the catalyst support material;
the zeolite particles; and
a first portion of the diluent;
the second mixture comprises:
the triblock copolymer surfactant; and
a second portion of the diluent; and
the third mixture comprises:
the catalytically active compound precursor; and
a third portion of the diluent.
9. The method of claim 8 in which the combining further comprises:
combining the second mixture and the third mixture to produce a fourth mixture, and
combining the first mixture and the fourth mixture to produce the catalyst precursor composition.
10. The method of claim 1 in which the drying chamber is maintained at a temperature of from 200° C. to 300° C.
11. The method of claim 1 further comprising:
removing a first composite catalyst from the drying chamber at a first outlet disposed at a bottom of the drying chamber; and
removing a second composite catalyst from the drying chamber at a second outlet upstream of the first outlet, where the second composite catalyst has an average particle size or a density less than an average particle size or a density, respectively of the first composite catalyst.
12. The method of claim 1 in which the catalytically active compound precursor comprises a metal selected from molybdenum, rhenium, tungsten, manganese, titanium, cerium, or any combination of these.
13. The method of claim 1 in which the catalytically active compound precursor comprises tungsten.
14. The method of claim 1 in which the catalytically active compound comprises an oxide of a metal selected from molybdenum, rhenium, tungsten, manganese, titanium, cerium, or any combination of these.
15. The method of claim 1 in which the catalyst precursor mixture comprises from 5 weight percent to 50 weight percent zeolite particles based on the dry weight of the catalyst precursor mixture.