Process for desulfurizing combustion exhaust gases
US4328195A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1980 |
| Grant date | May 4, 1982 |
| Priority date | — |
| Expiry date | Mar 14, 2000 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D53/68
- WIPO fieldChemical engineering
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.