Molybdenum-vanadium bimetallic oxide catalyst and its application in chemical looping oxidative dehydrogenation of alkane

Patent metadata

Field	Value
Publication number	US-2020122121-A1
Application number	US-201816605504-A
Country	US
Kind code	A1
Filing date	Jul 25, 2018
Priority date	Aug 8, 2017
Publication date	Apr 23, 2020
Grant date	—

Abstract

A molybdenum-vanadium bimetallic oxide catalyst and its application in the chemical looping oxidative dehydrogenation of alkane. The molecular formula of molybdenum-vanadium bimetallic oxide catalyst is MoVy and y represents the atomic molar ratio of vanadium and molybdenum. The supported MoVy catalyst is prepared by impregnation method, following the drying, calcination and tablet pressing. The reaction temperature was 450-550° C., and propane could be oxidized and dehydrogenated to propylene with high activity and selectivity, with propane conversion rate remaining at 30-40% and propylene selectivity at 80-90%. The fresh catalysts were reduced to the lower valence states with the lattice oxygen diffusion to propane. After the dehydrogenation, the reduced samples were regenerated to recover to the initial state and regain the lattice oxygen. During the redox cycles, the reaction performance remains stable, which can be used in the fixed bed reactor, moving bed reactor or circulating fluidized bed.

First claim

1 . A molybdenum-vanadium bimetallic oxide catalyst comprising a molar ratio of a metal Mo and a metal V is 1:(4-30) for a solid solution composed of a plurality of molybdenum oxides and a plurality of vanadium oxides, and the metal Mo enters a lattice of V 2 O 5 , resulting in a lattice distortion of V 2 O 5 and forming a molybdenum-vanadium solid solution.

2 . The molybdenum-vanadium bimetallic oxide catalyst according to claim 1 , wherein the preferred molar ratio of the metal Mo and the metal V is 1:(6-18).

3 . The molybdenum-vanadium bimetallic oxide catalyst according to claim 1 , wherein the catalyst is a supported catalyst, and a support is Al 2 O 3 , TiO 2 , SiO 2 or zeolites, a mass percentage of the molybdenum oxide is 1-30%, and a mass percentage of the vanadium oxide is 4-60%.

4 . The molybdenum-vanadium bimetallic oxide catalyst according to claim 3 , wherein the mass percentage of the molybdenum oxide is 10-20% and the mass percentage of the vanadium oxide is 40-60%.

5 . A preparation method of a molybdenum-vanadium bimetallic oxide catalyst, the method comprising:
step 1: evenly dispersing an ammonium metavadate and an oxalic acid in deionized water, and then adding an ammonium molybdate according to atom ratios of a vanadium and a molybdate to form a dipping solution; step 2, impregnating a support in the dipping solution prepared in the step 1 for an equal volume impregnation; step 3 , after the step 2, drying the support at 20-25° C. for 8 to 12 h, then at 60-80° C. for 10-12 h and, finally, calcinating samples at 500-600° C. for 2-4 h under air atmosphere; wherein, a molecular formula of the molybdenum-vanadium bimetallic oxide catalyst is MoVy, where y represents a ratio of metal V and Mo.

6 . The preparation method of molybdenum-vanadium bimetallic oxide catalyst according to claim 5 , wherein in the step 1 , a mass ratio of the oxalic acid and the ammonium metavanadate is (2.8-3):(1.5-2).

7 . The preparation method of molybdenum-vanadium bimetallic oxide catalyst according to claim 5 , wherein in the step 2 , the support is Al 2 O 3 , TiO 2 , SiO 2 or zeolites.

8 . The preparation method of molybdenum-vanadium bimetallic oxide catalyst according to claim 5 , wherein in the step 3 , the drying at 20-25° C. is performed for 10-12 h, and further comprises drying for 10-12 h at 80-90° C. before calcinating, at 500-600° C. for 2-4 h under air atmosphere.

9 . A method of chemical looping oxidative dehydrogenation of alkane, comprising: using the molybdenum-vanadium bimetallic oxide catalyst according to claim 1 .

10 . The method of chemical looping oxidative dehydrogenation according to claim 9 , wherein a reaction is under a plurality of anaerobic conditions and the molybdenum-vanadium bimetallic oxide catalyst serves as an oxygen carrier; wherein, the oxygen carrier reacts with a propane to produce a propylene and water to reduce the molybdenum-vanadium bimetallic oxide catalyst to a lower valence state.

11 . The method of chemical looping oxidative dehydrogenation according to claim 9 , wherein the alkane is an ethane, a propane, an n-butane and/or an isobutene.

12 . The method of chemical looping oxidative dehydrogenation according to claim 9 , wherein a gas-solid two-phase contact comprises countercurrent and concurrent contacts and a plurality of reactors comprises a fixed bed reactor, a moving bed reactor or a circulating fluidized bed reactor.

13 . The method of chemical looping oxidative dehydrogenation according to claim 10 , wherein a lattice oxygen of the molybdenum-vanadium bimetallic oxide catalyst is involved in the reaction; and as the reaction progresses, the lattice oxygen is consumed gradually, reducing the catalyst activity; and a regeneration by air or oxygen to regain the lattice oxygen is provided.

14 . The method of chemical looping oxidative dehydrogenation according to claim 9 , wherein the reaction is carried out under the atmospheric pressure at a reaction temperature of 450-550° C. using the molybdenum-vanadium bimetallic oxide catalyst and quartz sand mixture; a weight hourly space velocity (WHSV) of propane is 0.5-2 h −1 , and a propane volume percentage is 10-30%.

15 . The molybdenum-vanadium bimetallic oxide catalyst according to claim 2 , wherein the catalyst is a supported catalyst, and a support is Al 2 O 3 , TiO 2 , SiO 2 or zeolites, a mass percentage of the molybdenum oxide is 1-30%, and a mass percentage of the vanadium oxide is 4-60%.

16 . The method of chemical looping oxidative dehydrogenation according to claim 10 , wherein the alkane is an ethane, a propane, an n-butane and/or an isobutene.

17 . The method of chemical looping oxidative dehydrogenation according to claim 10 , wherein a gas-solid two-phase contact comprises countercurrent and concurrent contacts and a plurality of reactors comprises a fixed bed reactor, a moving bed reactor or a circulating fluidized bed reactor.

18 . The method of chemical looping oxidative dehydrogenation according to claim 10 , wherein the reaction is carried out under the atmospheric pressure at a reaction temperature of 450-550° C. using the molybdenum-vanadium bimetallic oxide catalyst and quartz sand mixture; a weight hourly space velocity (WHSV) of propane is 0.5-2 h −1 , and a propane volume percentage is 10-30%.

Assignees

• Univ Tianjin

Inventors

• Gong Jinlong
• Chen Sai
• Zeng Liang
• Mu Rentao

Classifications

• C07C2523/28

  Molybdenum · CPC title

• C07C2523/89

  combined with noble metals · CPC title

• B01J21/063

  Titanium; Oxides or hydroxides thereof · CPC title

• B01J21/04

  Alumina · CPC title

• B01J38/12

  Treating with free oxygen-containing gas · CPC title