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:
Sep. 25, 1979
Filed:
Jan. 21, 1977
Lars Hellmer, Widdersdorf, DE;
Gerhard Keunecke, Geyen, DE;
Davy Powergas GmbH, Cologne, DE;
Abstract
A process for utilization of the reaction heat generated by the catalytic oxidation of o-xylene with air to phthalic anhydride in a tubular reactor, which heat is partially carried away from the reactor by the reaction gas and partially by fused salt used as a cooling medium. Water is heated by heat exchange with the hot reaction gas, evaporated by heat exchange with the fused salt and the steam is superheated and expanded in a condensation turbine coupled with the feed air compressor. The hot reaction gas is used successively to heat, or evaporate, a heat carrier liquid serving for the heating of the phthalic anhydride distillation, and the pressurized water. Low pressure steam can be generated by heat exchange of pressurized water with the reaction gas and used for heating the feed air and/or o-xylene. Preferably, the evaporation and superheating of the heated pressure water is effected in two fused salt cooling stages; the compressed air is successively heated by heat exchange with low pressure steam generated by cooling of the reaction gas and with the high pressure steam generated by cooling of the fused salt; and, the heating liquid and the pressurized water are heated in a two-stage heat exchanger.