| Titre : | Conductive monolithic catalysts : Development and industrial pilot tests for the oxidation of o - xylene to phthalic anhydride (2012) |
| Auteurs : | Gianpiero Groppi, Auteur ; Enrico Tronconi, Auteur ; Carlotta Cortelli, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Industrial & engineering chemistry research (Vol. 51 N° 22, Juin 2012) |
| Article en page(s) : | pp. 7590-7596 |
| Note générale : | Industrial chemistry |
| Langues : | Anglais |
| Tags : | Oxidation Catalyst Monolithic construction |
| Résumé : | We present herein results from a campaign (>1500 h) of o-xylene oxidation runs in a 1 in. single-tube technical fixed- bed pilot reactor (i.d = 24.6 mm) loaded with 16 washcoated (V2O5/TiO2) monolithic catalysts with Al honeycomb supports (each 10 cm long) and operated at typical industrial conditions for PA (phthalic anhydride) production. The highly conductive monolithic supports afforded substantially reduced axial T-gradients in comparison with reference runs in the same pilot reactor loaded with conventional egg-shell ring catalyst pellets, the maximum T-difference with the salt bath being halved at the same hot spot temperature (∼440 °C) and the mean bed temperature being about 20 °C higher. Temperature gradients were still moderate at an o-xylene feed concentration of 80 g/Nm3 (at Qair = 4 N m3/h), which represents an upper limit for industrial PA packed-bed reactors loaded with the same V2O5/TiO2 catalyst coated onto ring pellets. Operation at higher o-xylene feed contents (up to 95 g/Nm3) was found feasible. The Al honeycomb catalysts were successfully unloaded at the end ofthe runs. The strong (∼2-fold) enhancement of radial heat transfer rates associated with the adoption of highly conductive monolith catalyst supports is thus herein demonstrated at a fully representative industrial scale for the first time. It can be exploited, for instance, either to increase the o-aylene feed concentration, possibly above 100 g/Nm3 (and the PA productivity accordingly), within a retrofitting strategy, or to design new reactors with larger tube diameters, resulting in reduced investment costs. |
| ISSN : | 0888-5885 |
| En ligne : | http://cat.inist.fr/?aModele=afficheN&cpsidt=25968312 |
