Process for simultaneous removal of SO.sub.2 and NO.sub.x from gas streams

Patent · Thu Jan 01 04:00:00 EST 1987

OSTI ID:866126

Rosenberg, Harvey S ^[1]

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1. Columbus, OH

A process for simultaneous removal of SO.sub.2 and NO.sub.x from a gas stream that includes flowing the gas stream to a spray dryer and absorbing a portion of the SO.sub.2 content of the gas stream and a portion of the NO.sub.x content of the gas stream with ZnO by contacting the gas stream with a spray of an aqueous ZnO slurry; controlling the gas outlet temperature of the spray dryer to within the range of about a 0.degree. to 125.degree. F. approach to the adiabatic saturation temperature; flowing the gas, unreacted ZnO and absorbed SO.sub.2 and NO.sub.x from the spray dryer to a fabric filter and collecting any solids therein and absorbing a portion of the SO.sub.2 remaining in the gas stream and a portion of the NO.sub.x remaining in the gas stream with ZnO; and controlling the ZnO content of the aqueous slurry so that sufficient unreacted ZnO is present in the solids collected in the fabric filter to react with SO.sub.2 and NO.sub.x as the gas passes through the fabric filter whereby the overall feed ratio of ZnO to SO.sub.2 plus NO.sub.x is about 1.0 to 4.0 moles of ZnO per of SO.sub.2 and about 0.5 to 2.0 moles of ZnO per mole of NO.sub.x. Particulates may be removed from the gas stream prior to treatment in the spray dryer. The process further allows regeneration of ZnO that has reacted to absorb SO.sub.2 and NO.sub.x from the gas stream and acid recovery.

• Research Organization: BATTELLE MEMORIAL INSTITUTE
• DOE Contract Number: AC22-83PC60264
• Assignee: Battelle Memorial Institute (Columbus, OH)
• Patent Number(s): US 4640825
• OSTI ID: 866126
• Country of Publication: United States
• Language: English

Related Subjects

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absorb
absorbed
absorbing
acid
adiabatic
allows
approach
aqueous
aqueous slurry
collected
collecting
contacting
content
controlling
degree
dryer
fabric
feed
filter
flowing
gas
gas outlet
gas passes
gas stream
gas streams
mole
moles
outlet
outlet temperature
overall
particulates
passes
plus
portion
prior
process
range
ratio
react
reacted
recovery
regeneration
remaining
removal
removed
saturation
saturation temperature
simultaneous
simultaneous removal
slurry
solids
spray
spray dryer
stream
stream prior
streams
sufficient
temperature
therein
treatment
unreacted
whereby
zno