The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 20, 1999
Filed:
Sep. 30, 1997
Rashmikant Maganlal Contractor, Ardentown, DE (US);
Harold Saul Horowitz, Wilmington, DE (US);
Gregory Scott Patience, Wilmington, DE (US);
John Donal Sullivan, Wilmington, DE (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
An improved process for calcination and activation of a catalyst containing mixed oxides of vanadium and phosphorus (V/P/O) involving the addition of spray dried catalyst precursor to a fluidizing oxygen containing gas at a controlled rate such that the temperature is maintained at a range of 370 to 410.degree. C. (preferably 390.+-.5.degree. C.). The catalyst precursor experiences, in addition to rapid temperature rise, dehydration/calcination at this elevated temperature in the fluidized state for an average range of residence time of less than about 4 hours at 3.5 atm of air or above, and up to 20 hours at 1 atm of air while simultaneously and continuously maintaining an average V.sub.ox of 4.55 or less. Such a process is useful in preparing a V/P/O catalyst that exhibits enhanced activity for the oxidation of n-butane to maleic anhydride. The novel process also provides an improved method for start-up of a commercial scale recirculating solids reactor.