Process for removal of sulfur dioxide from gas streams
An improved apparatus and process are disclosed for the removal of sulfur oxides such as sulfur dioxide from waste gas streams. The process comprises scrubbing the waste gas with a circulating aqueous sodium sulfite/sodium bisulfite absorption solution at a relatively low ph followed by subjecting a portion of the circulating absorption solution to an improved multi-stage regeneration procedure wherein lime is employed to regenerate sulfite from bisulfite. The bleed from the scrubbing step which is subjected to regneration has a low ph and hence can dissolve more lime thereby increasing the lime utilization efficiency. In the regeneration procedure, a lime slurry is separated into a slurry of coarser lime particles and a second portion which contains very fine lime particles. The main regeneration is accomplished by adding the coarse lime slurry to the scrubber bleed. Due to the low ph in this reaction, not all the bisulfite is regenerated to sulfite. However, any remaining bisulfite is regenerated to sulfite in later regeneration steps by reaction with the second portion of the lime slurry in order to precipitate as much calcium as possible in the form of sulfate.
- Assignee:
- Neptune Airpol Inc
- Patent Number(s):
- US 4313924
- OSTI ID:
- 5494892
- Country of Publication:
- United States
- Language:
- English
Similar Records
Double alkali process for removal of sulfur dioxide from gas streams
Method using lime slurry for regenerating sodium sulfite in double alkali flue gas desulfurization process
Related Subjects
010800* -- Coal
Lignite
& Peat-- Waste Management
02 PETROLEUM
020800 -- Petroleum-- Waste Management
03 NATURAL GAS
030700 -- Natural Gas-- Waste Management
04 OIL SHALES AND TAR SANDS
040900 -- Oil Shales & Tar Sands-- Waste management
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ABSORPTION
CHALCOGENIDES
CHEMICAL REACTIONS
DESULFURIZATION
DISPERSIONS
FLUE GAS
GASEOUS WASTES
LIME-LIMESTONE WET SCRUBBING PROCESSES
MIXTURES
OXIDES
OXYGEN COMPOUNDS
PH VALUE
RECYCLING
REMOVAL
SCRUBBING
SLURRIES
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
SUSPENSIONS
WASTES