能源化学(英文版)

能源化学(英文) ›› 2005, Vol. 14 ›› Issue (2): 88-94.

• Articles • 上一篇    下一篇

Selective Oxidation of Propane by Lattice Oxygen of Vanadium-Phosphorous Oxide in a Pulse Reactor

Rusong Zhao, Jian Wang, Qun Dong, Jianhong Liu   

  1. 1. College of Chemistry and Chemical Engineering, Beijing Petrochemical Institute, Beijing 102617, China; 2. College of Chemistry and Chemical Engineering, Daqing Petroleum Institute, Daqing 163318, China
  • 出版日期:2005-06-30 发布日期:2005-06-30

Selective Oxidation of Propane by Lattice Oxygen of Vanadium-Phosphorous Oxide in a Pulse Reactor

Rusong Zhao, Jian Wang, Qun Dong, Jianhong Liu   

  • Online:2005-06-30 Published:2005-06-30

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摘要： Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide (VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and the re-oxidation of catalyst were implemented alternately in the presence of water vapor. The principal products are acrylic acid (AA), acetic acid (HAc), and carbon oxides. In addition, small amounts of C1 and C2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4–2.2. The active oxygen species are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. lattice oxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulating fluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reaction temperature in a pulse reactor were found almost the same as in a steady-state flow reactor. That is, as the reaction temperature increases, propane conversion and the amount of C1+C2 hydrocarbons in the product increase steadily, while selectivity to acrylic acid and to acetic acid increase prior to 350oC . then begin to drop at temperatures higher than 350 oC, and yields of acrylic acid and of acetic acid attained maximum at about 400 oC. The maximum yields of acrylic acid and of acetic acid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When the amount of propane pulsed decreases or the amount of catalyst loaded increases, the conversion increases but the selectivity decreases. Increasing the flow rate of carrier gases causes the conversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bed reactor, it is hard to obtain high selectivity at a high reaction conversion due to the further degradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen. The catalytic performance can be improved in the presence of excess propane. Propylene can be oxidized by lattice oxygen of VPO catalyst at 250 oC, nevertheless, selectivity to AA and to HAc are even lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1–0.83:1) though the oxidation products are the same as from propane.

关键词: propane oxidation, acrylic acid, acetic acid, vanadium-phosphorus oxide, lattice oxygen oxidation, pulse reaction

Abstract: Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide (VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and the re-oxidation of catalyst were implemented alternately in the presence of water vapor. The principal products are acrylic acid (AA), acetic acid (HAc), and carbon oxides. In addition, small amounts of C1 and C2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4–2.2. The active oxygen species are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. lattice oxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulating fluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reaction temperature in a pulse reactor were found almost the same as in a steady-state flow reactor. That is, as the reaction temperature increases, propane conversion and the amount of C1+C2 hydrocarbons in the product increase steadily, while selectivity to acrylic acid and to acetic acid increase prior to 350oC . then begin to drop at temperatures higher than 350 oC, and yields of acrylic acid and of acetic acid attained maximum at about 400 oC. The maximum yields of acrylic acid and of acetic acid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When the amount of propane pulsed decreases or the amount of catalyst loaded increases, the conversion increases but the selectivity decreases. Increasing the flow rate of carrier gases causes the conversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bed reactor, it is hard to obtain high selectivity at a high reaction conversion due to the further degradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen. The catalytic performance can be improved in the presence of excess propane. Propylene can be oxidized by lattice oxygen of VPO catalyst at 250 oC, nevertheless, selectivity to AA and to HAc are even lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1–0.83:1) though the oxidation products are the same as from propane.

Key words: propane oxidation, acrylic acid, acetic acid, vanadium-phosphorus oxide, lattice oxygen oxidation, pulse reaction