Process for desulfurizing combustion exhaust gases
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 caso3; a second step of contacting O2 with the resulting slurry to convert CaSo3 into caso4; a third step of separating caso4 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 so2absorbent (CaCO3 or Ca(OH)2) with SO2 gas, and thereby improve percentage desulfurization and also obtain a high quality gypsum.
- Assignee:
- Babcock-Hitachi K.K.
- Patent Number(s):
- US 4328195
- OSTI ID:
- 5254142
- Resource Relation:
- Patent Priority Date: Priority date 19 Mar 1979, Japan; Other Information: PAT-APPL-130388
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
02 PETROLEUM
COAL
COMBUSTION PRODUCTS
EXHAUST GASES
DESULFURIZATION
ALUMINIUM
CALCIUM CARBONATES
DUSTS
HYDROFLUORIC ACID
OXIDATION
SEPARATION PROCESSES
SLURRIES
SULFUR DIOXIDE
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONACEOUS MATERIALS
CARBONATES
CHALCOGENIDES
CHEMICAL REACTIONS
DISPERSIONS
ELEMENTS
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUELS
GASEOUS WASTES
GASES
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MATERIALS
METALS
MIXTURES
OXIDES
OXYGEN COMPOUNDS
SULFUR COMPOUNDS
SULFUR OXIDES
SUSPENSIONS
WASTES
010402* - Coal
Lignite
& Peat- Purification & Upgrading
020800 - Petroleum- Waste Management