Process for removing sulfur oxides from gas streams

Patent · Tue Nov 02 04:00:00 EST 1976

OSTI ID:7321529

Brady, J D; Legatski, L K

In a system for removing sulfur oxides from flue gas, the gas is contacted by a primary extraction solution containing sodium sulfite as the active compound and some sodium bisulfite in a scrubber, and the resultant extract containing more sodium bisulfite is mixed with an alkaline solution containing regenerated sodium sulfite in a mixer to produce the primary extraction solution. A portion of the latter is bled off to a regenerator wherein the quantity of sodium bisulfite made in the scrubber reacts with calcium hydroxide to form regenerated sodium sulfite and large diameter calcium sulfite precipitates that remain suspended in the parent solution. This mixture is drawn off the regenerator by overflow, without pumping, for gravity flow to the eye of a thickener, wherein an increased density slurry of the mixture is withdrawn from the thickener well and directed to a rotary filter to produce a calcium sulfite filter cake. The resultant filtrate and the solids free overflow from the thickener provide the sodium sulfite solution inputs to a holding tank, from which the liquor is pumped through a back washed polishing filter and back to the mixer. Flyash, initially present in the incoming flue gas, is separated from the gas in the scrubber and passes through the system to the filter, where it acts as a filter-aid.

• Assignee: FMC Corp.
• Patent Number(s): US 3989797
• OSTI ID: 7321529
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
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500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AEROSOL WASTES
AIR POLLUTION CONTROL
CHALCOGENIDES
CHEMICAL REACTIONS
DESIGN
DESULFURIZATION
EQUIPMENT
FILTERS
FLUE GAS
FLY ASH
GASEOUS WASTES
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
REMOVAL
SCRUBBERS
SULFUR COMPOUNDS
SULFUR OXIDES
WASTES