Chemical homogeneity and catalytic performance of mixed-metal oxide catalysts
AssigneeUop LLC
InventorsJames M. Hodges, Joel T. Walenga, Scott Lyle Nauert
Life of this patent
Estimating the term…
Abstract
A method for preparing a mixed-metal oxide catalyst comprising molybdenum, vanadium, at least one of niobium or tantalum, and at least one of tellurium or antimony and useful for the oxidative dehydrogenation of ethane to ethylene, the method comprising preparing a catalyst precursor, pressing the precursor into a dense pellet using a pressure of greater than about 5,000 psi, and annealing the pellet to form the mixed-metal oxide catalyst.
Claims13
A mixed-metal oxide catalyst for the oxidative dehydrogenation of ethane to ethylene, the catalyst prepared by the method comprising:
- (a) preparing a catalyst precursor comprising molybdenum, vanadium, at least one of niobium or tantalum, and at least one of tellurium or antimony;
- (b) pressing the catalyst precursor into a dense pellet using a pressure of greater than about 5,000 psi;
- (c) annealing the dense pellet at a temperature of from about 525° C. to about 700° C. in a non-oxidative environment for a period of from about 0.5 hours to about 24 hours to form the mixed-metal oxide catalyst;
- and
- (d) optionally grinding the mixed-metal oxide catalyst into a fine powder and repeating steps (b) and (c),
- wherein after annealing of the dense pellet in step (c), the mixed-metal oxide catalyst is characterized by a local distribution of elements comprising of a standard deviation in molybdenum decreasing in a range of σMo=9.5 wt % to σMo<3.2 wt %, and a standard deviation in vanadium decreasing in a range of σv=3.3 wt % to a σv<0.9 wt %.
A method of oxidative dehydrogenating ethane to ethylene in the presence of a mixed-metal oxide catalyst comprising contacting a gas composition containing ethane with the mixed metal oxide catalyst in the temperature range of 300-450° C., a pressure of 15 psig, a gas hourly space velocity of 2000 cm3/h per gram of the mixed metal oxide catalyst, wherein the gas composition having a ratio of ethane:O2:N2 in a range from 1.6:1:5 to 2:1:5;
- wherein the mixed metal oxide catalyst prepared by the method comprising:
- a. preparing a catalyst precursor comprising molybdenum, vanadium, at least one of niobium or tantalum, and at least one of tellurium or antimony;
- b. pressing the catalyst precursor into a dense pellet using a pressure of greater than about 5,000 psi;
- c. annealing the dense pellet at a temperature of from about 525° C. to about 700° C. in a non-oxidative environment for a period of from about 0.5 hours to about 24 hours to form the mixed-metal oxide catalyst;
- and
- d. optionally grinding the mixed-metal oxide catalyst into a fine powder and repeating steps (b) and (c),
- wherein after annealing of the dense pellet in step (c), the mixed-metal oxide catalyst is characterized by a local distribution of elements comprising of a standard deviation in molybdenum decreasing in a range of σMo=9.5 wt % to σ<3.2 wt %, and a standard deviation in vanadium decreasing in a range of σv=3.3 wt % to σv<0.9 wt %.
Dependencies are inferred from the claim text.