| 摘要 |
The invention relates to a method for producing maleic anhydride by the heterogeneous catalytic gas phase oxidation of hydrocarbons comprising at least four carbon atoms with gases containing oxygen, in the presence of a volatile phosphorus compound, on a catalyst containing vanadium, phosphor an d oxygen in a multitube flow reactor unit with at least one reaction zone that is cooled by a heat-transfer medium, at a temperature ranging between 350 an d 500 ~C. In the first reaction zone, in relation to the educt supply, the supply temperature and/or the supply quantity is set in such a way that the average temperature of the heat transfer medium in the first reaction zone TSB(1st zone), said temperature being produced by the average value formatio n of the supply temperature and the drainage temperature of the heat-transfer medium, fulfils the formulas (I) and (II): (I) TSB(1st zone) <= TD(1st zo ne) - TSafety(1st zone); (II) TSB,Amax(1st zone) - TA(1st zone) <= TSB(1st zone ) <= TSB,Amax(1st zone) + TB(1st zone), whereby TD(1st zone) represents the throughput temperature of the first reaction zone, TSafety(1st zone) represents the safety temperature of the first reaction zone and is 1 ~C; TSB,Amax(1st zone) represents the average temperature of the heat-transfer medium in the first reaction zone, the maximum yield of maleic anhydride bei ng obtained in the range TSB(1st zone) <= TD(1st zone), TA(1st zone) is 20 ~ C and TB(1st zone) is 10 ~C.
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