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:
May. 04, 1982
Filed:
Mar. 14, 1980
Toshikatsu Mori, Hitachi, JP;
Teruo Kumagai, Hitachi, JP;
Shinpei Matsuda, Hitachi, JP;
Tsukasa Nishimura, Kure, JP;
Yasuyuki Nishimura, Kure, JP;
Babcock-Hitachi, Ltd., Tokyo, JP;
Abstract
An improved process for desulfurizing combustion exhaust gases of mainly coal containing sulfur oxides, HF and dust containing Al is provided, which process consists of four steps; a first step of contacting the gases with calcium carbonate or hydroxide in the form of slurry to convert the sulfur oxides into CaSO.sub.3 ; a second step of contacting O.sub.2 with the resulting slurry to convert CaSO.sub.3 into CaSO.sub.4 ; a third step of separating CaSO.sub.4 and mother liquor from the resulting slurry; and a fourth step of preparing a slurry of calcium carbonate or hydroxide to be employed in the first step, from the mother liquor, the pHs of the slurry and the mother liquor in the first and fourth steps being adjusted to 5 or higher by adding alkali such as sodium carbonate. According to the present process, it is possible to prevent hindrance of HF and Al contained in dust to the reaction of SO.sub.2 -absorbent (CaCO.sub.3 or Ca[OH].sub.2) with SO.sub.2 gas, and thereby improve percentage desulfurization and also obtain a high quality gypsum.