Control of nitric acid plant stack opacity during start-up and shutdown

Patent · Tue Sep 26 04:00:00 EDT 1989

OSTI ID:7256171

Adams, J B; Gasper, J A; Stash, P J

This patent describes an improvement in a process for the production of nitric acid wherein air and ammonia are mixed and combusted in an ammonia burner to produce an effluent containing nitrogen oxides. The effluent is cooled, condensed and separated into a liquid weak acid stream and gas stream. The liquid weak acid and vapor streams are fed into an absorber tower wherein they are countercurrently contacted with water to produce a nitric acid stream and an overhead with a reduced nitrogen oxides content. The overhead is combusted with a fuel in the presence of a catalyst in a catalytic combustor to produce a combustor exhaust, work expanded in an expander to recover energy and vented to the atmosphere as stack exhaust. The improvement involves controlling the opacity of the stack opacity during shutdown of the process.

• Assignee: Air Products and Chemicals, Inc., Allentown, PA
• Patent Number(s): US 4869890
• Application Number: PPN: US 7-177713A
• OSTI ID: 7256171
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AIR
AIR POLLUTION CONTROL
AMMONIA
CHALCOGENIDES
CHEMICAL PLANTS
CONTROL
FLUIDS
GASEOUS WASTES
GASES
HYDRIDES
HYDROGEN COMPOUNDS
INDUSTRIAL PLANTS
INORGANIC ACIDS
MANAGEMENT
NITRIC ACID
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
PROCESSING
PRODUCTION
WASTE MANAGEMENT
WASTE PROCESSING
WASTES