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:
Jul. 04, 2000
Filed:
Jul. 30, 1997
Thomas D Wheelock, Ames, IA (US);
Iowa State University Research Foundation, Inc., Ames, IA (US);
Abstract
Calcium sulfide particles in mixtures with carbon particles, as in coal gasifier waste, are converted to calcium oxide by repeated cycles of oxidation and reduction by utilizing the carbon as a source of the reducing gas required for the treatment. The treatment can be conducted in a two zone fluidized bed reactor by limiting the amount and concentration of oxygen supplied to a lower reducing zone and by supplying excess oxygen to an upper oxidizing zone. Alternatively, for particles less than 0.5 mm in size, the treatment can be conducted by utilizing either two transport reactors or two circulating fluidized bed reactors in series whereby the first reactor in the series is maintained in a reducing state and the second reactor is maintained in an oxidizing state. The particles are transported sequentially through both reactors and recycled several times. The amount and concentration of oxygen supplied to the first reactor is limited to create reducing conditions, while excess oxygen is supplied to the second reactor to create oxidizing conditions.