Catalyst compositions and use thereof in catalytic biomass pyrolysis
A catalyst is described that is useful for catalytic pyrolysis of biomass to produce a pyrolysis product. The catalyst includes (i) matrix material comprising a support and/or binder, and (ii) at least one metal oxide on the matrix material, wherein the metal oxide comprises metal selected from the group consisting of tungsten, chromium, cobalt, molybdenum, nickel, and combinations thereof. Corresponding catalytic pyrolysis processes and catalytic pyrolysis apparatus are disclosed, in which the catalyst enables the production of low oxygen content, stable liquid intermediates that can be refined to make liquid hydrocarbon fuels.
1. A catalyst useful for catalytic pyrolysis of biomass, said catalyst comprising:
(i) matrix material comprising a support and/or binder, and
(ii) at least one metal oxide on the matrix material, wherein the metal oxide comprises metal selected from the group consisting of tungsten, chromium, molybdenum, nickel, and combinations thereof,
having an acid site loading, as measured by ammonia adsorption, in a range of from 3 to 10 mL of NH 3 per gram of catalyst,
wherein the catalyst does not contain cobalt,
wherein when the catalyst comprises a catalytic promoter, the catalytic promoter is elemental metal selected from the group consisting of platinum, palladium, ruthenium, nickel, molybdenum, hafnium, copper, iron, tin, manganese, magnesium, chromium, lanthanum, and combinations thereof, and
wherein the metal oxide has a loading on the matrix material of from 10 to 20% by weight, based on total weight of the metal oxide and matrix material, with the proviso that when the metal oxide comprises tungsten oxide and the matrix material comprises zirconia, the tungsten oxide has a loading on the zirconia of from 15% to 17% by weight, based on total weight of the tungsten oxide and zirconia.
2. The catalyst of claim 1 , wherein Lewis acid and Brønsted acid sites are present on the catalyst at a Lewis to Brønsted infrared band height ratio (cm −1 /cm −1 ) in a range of from 0.1 to 50.
3. The catalyst of claim 1 , wherein the metal oxide comprises tungsten oxide and the matrix material comprises zirconia.
4. The catalyst of claim 1 , of particulate form, having an average particle size in a range of from 20 to 150 μm.
5. The catalyst of claim 1 , having: a tap bulk density in a range of from 0.5 to 2.2 gm per cc of catalyst; a BET surface area in a range of from 20 to 150 m 2 /gram; porosity providing a pore volume in a range of from 0.2 to 1.0 cc of pore volume per gram of catalyst; and an Attrition Index in a range of from 2 to 25.
6. The catalyst of claim 1 , wherein the metal oxide comprises tungsten oxide.
7. The catalyst of claim 1 , wherein the matrix material comprises a support comprising material selected from the group consisting of titania, alumina, silica, ceria, zirconia, zeolites, and compatible mixtures, alloys, and composites of two or more of the foregoing.
8. The catalyst of claim 1 , comprising a zirconia support comprising tetragonal phase zirconia, wherein the metal oxide comprises tungsten oxide.
9. The catalyst of claim 1 , further comprising a catalytic promoter selected from the group consisting of platinum, palladium, ruthenium, nickel, molybdenum, hafnium, copper, iron, tin, manganese, magnesium, chromium, lanthanum, and combinations thereof.
10. A catalyst useful for catalyzing pyrolysis of biomass, said catalyst comprising a zirconia support and tungsten oxide on the zirconia support at a tungsten oxide loading of from 15% to 17% by weight, based on total weight of zirconia and tungsten oxide, said catalyst being of particulate form with an average particle size in a range of from 20 to 150 μm, with an acid site loading, as measured by ammonia adsorption, in a range of from 3 to 10 mL of NH 3 per gram of catalyst, and wherein Lewis acid and Brønsted acid sites are present on the catalyst at a Lewis to Brønsted infrared band height ratio (cm −1 /cm −1 ) in a range of from 0.1 to 50, wherein the catalyst does not contain cobalt, and wherein when the catalyst comprises a catalytic promoter, the catalytic promoter is elemental metal selected from the group consisting of platinum, palladium, ruthenium, nickel, molybdenum, hafnium, copper, iron, tin, manganese, magnesium, chromium, lanthanum, and combinations thereof.