Research Of The VPO Catalyst For Selective Oxidation Of Butane

The VPO catalysts were prepared by organic method,the effect of organic solvent and its ratio、solvent removal and its amount、concentration of phosphoric acid and P/V ratio、 catalyst elements and additive amount to prepare VPO catalyst precursors were investigated in order to develop the catalyst for maleic anhydride from butane with good selectivity and stability.SEM、XRD、XPS and BET characterization means were employed to study the phase composition and surface area of VPO catalysts,the results show that the main active phase of the VPO precursor is VOHPO4·0.5H2O,and the main active phase of catalyst after activation is (VO)2P2O7.The doping of Mo can improve the selectivity of the catalyst obviously,and the catalyst prepared by100%phosphoric acid and P/V=0.95-1.00showed better catalytic performance,catalyst elements wouldn’t change the main active phase of catalyst.Studied the effects of temperature and atmosphere in activation to the active phase and performance of catalyst through the characterization means and fixed bed reactor as the above mentioned.Better activation temperature is425℃when the activation atmosphere consisted of A5-7vol%and B25vol%.Optimized the process condition parameter of oxidation of butane to maleic anhydride in the fixed bed reactor.The influence rule of process conditions to reaction through the investigation of reaction temperature、initial concentration of butane and space velocity were examined.The better reaction condition is:reaction temperature is395℃,space velocity is2000-2250h-1and initial concentration of n-butane is1.4-1.5mol%.Tested the stability of prepared VPO catalyst which was tested yet under above reaction condition in the fixed bed reactor,the reaction period of500hours unchanged the main active phase of catalyst and its performance was stable.