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. 26, 2005
Filed:
Jan. 21, 2003
Thomas Gutermuth, Maintal, DE;
Helmuth Domes, Obertshausen, DE;
Thomas Gutermuth, Maintal, DE;
Helmuth Domes, Obertshausen, DE;
Lurgi AG, Frankfurt am Main, DE;
Abstract
To improve the columns used so far for producing phthalic anhydride, and to make them less expensive and easier to install, it is proposed that in the column for concentrating phthalic anhydride two distillation stages are arranged, wherein the removal of the low-boiling components of the crude phthalic anhydride by distillation is effected in the first distillation stage () and the separation of the high-boiling components from the pure phthalic anhydride is effected in the second distillation stage (), both distillation stages being arranged side by side and being separated from each other by a vertical wall (), and that the bottom () of the first distillation stage () is connected with the bottom () of the second distillation stage ().