PROCEDIMENTO MIGLIORATO PER LA CALCINAZIONE/ATTIVAZIONE DI UN CATALIZZATORE V/P/O

摘要

Selective gas phase oxidation of n-butane to maleic anhydride is carried out in a transfer bed reactor with (1) a reaction zone, in which n-butane is converted to maleic anhydride with a vanadium/phosphorus oxide catalyst (V/P/O catalyst) in the oxidised form and (2) a catalyst regeneration zone, in which the reduced V/P/O catalyst is regenerated by contact with oxygen (O2). The novel features are that (i) the catalyst precursor is introduced into the regeneration zone, which is kept at 380-400 deg C; (ii) the precursor is fluidised with air or gas containing O2 for long enough and at a suitable pressure to remove entrained organic compound and (partly) dehydrate the precursor; (iii) the calcined precursor is transferred to the reaction zone after an average residence time giving an average vanadium oxidation state (Vox) <= 4.55; and (iv) the calcined precursor is kept in the fluidised state in the reaction zone with a non-oxidising gas until the start of catalyst circulation. Also claimed is a method for calcining a V/P/O catalyst.