Long term operation of heterogeneously catalyzed partial gas phase oxidation of propene to acrolein, comprises conducting reaction gas input mixture containing propene, molecular oxygen and inert gas, through solid catalyst bed

摘要

Long term operation of a heterogeneously catalyzed partial gas phase oxidation of propene to acrolein, comprises conducting a reaction gas input mixture containing propene, molecular oxygen and at least one inert gas, through a solid catalyst bed, whose active mass is at least one multi-metal oxide containing molybdenum, iron and bismuth. The reaction gas input mixture comprises the molecular oxygen and the propene in a molar ratio of >= 1. The solid catalyst bed is arranged in two spatial successive temperature zones A and B. Long term operation of a heterogeneously catalyzed partial gas phase oxidation of propene to acrolein, comprises conducting a reaction gas input mixture containing propene, molecular oxygen and at least one inert gas, through a solid catalyst bed, whose active mass is at least one multi-metal oxide containing molybdenum, iron and bismuth. The reaction gas input mixture comprises the molecular oxygen and the propene in a molar ratio of >= 1. The solid catalyst bed is arranged in two spatial successive temperature zones A and B. The temperature of the zone A (TA) and the temperature of the zone B (TB) is 280-420[deg] C. The reaction gas input mixture flows first through the temperature zone A and then through the temperature zone B. The amount of propene contained in the reaction gas input mixture, converted in temperature zone A (UA), is upto 45-85 mole%. The amount of propene converted in temperature zone B (UB) is increased to >= 90 mole%. The selectivity of the formed acrolein based on the reacted propylene, during the single passage of the reaction gas input mixture through the entire solid bed catalyst, amounts to >= 80 mole%. The loading of the solid catalyst bed with the propene, amounts to >= 140 standard liters of propene per liter of solid catalyst bed per hour. The temperatures (TA) and (TB), after carrying out fresh loading of the solid catalyst bed, are provided such that the difference of temperatures (delta TBA) of zones A (TA) and B (TB), is greater than 0[deg] C. At least one of the two temperatures (TA) and (TB) is increased, for counteracting the degradation of the solid catalyst bed with the subsequent increase of operating time. The increase of at least one of the two temperatures (TA) and (TB) is carried out such that the difference of temperatures (delta TBA) increases with the increase of the operating time.