Patents by Inventor William Joseph Letts

William Joseph Letts has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6107238
    Abstract: A method for manufacturing of an improved attrition resistant catalyst having an oxide-rich surface layer involving forming a slurry comprising; catalyst, catalyst precursor or catalyst support particles (e.g., transition metal oxides), a colloidal oxide sol (e.g., colloidal silica), and a solution of a solvent and solute wherein the solute consist essentially of a precursor of said oxide-rich surface with particle size no greater than 5 nm (e.g., aqueous silicic acid or polysilicic acid) and then spray drying the slurry to form porous microspheres of attrition resistant catalyst; and, calcining the spray dried microspheres. Such a catalyst is particularly useful in oxidation processes wherein the oxidation is performed by an oxidized form of the catalyst and the resulting reduced form of the catalyst is separately regenerated (e.g., two-step vapor phase processes carried out in recirculating solids reactors, transport bed reactors or circulating fluidized bed reactors and the like).
    Type: Grant
    Filed: September 30, 1998
    Date of Patent: August 22, 2000
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Rashmikant Maganlal Contractor, William Joseph Letts