Combined nitrogen oxides/sulfur dioxide control in a spray- dryer/fabric-filter system

Technical Report · Wed Apr 01 04:00:00 EST 1987

DOI:https://doi.org/10.2172/7126788· OSTI ID:7126788

Farber, P S ^[1]; Huang, H S ^[2]

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1. Chemical Waste Management, Inc., Oakbrook, IL (USA)
2. Argonne National Lab., IL (USA). Energy Systems Div.

Caustic soda was evaluated for its value as an additive in combined nitrogen oxides/sulfur oxides (NO{sub x}/SO{sub x}) removal from coal combustion gases in a four-week field test at a 22-MW (electric) industrial-scale spray-dryer facility at Argonne National Laboratory (ANL). A combination of modified process conditions and additions of caustic soda to the lime-based spary-dryer system yielded some removal of NO{sub X} from the flue gases, but an increased sorbent ratio was needed to maintain the SO{sub 2}-removal ability. The higher concentration of NO{sub 2} at the system outlet than at the inlet indicated that the oxidation of NO to NO{sub 2} was a key step in the overall removal process; a large increase in the concentration of nitrates was correlated with the increased oxidation of NO to NO{sub 2}. The test data also indicated that the outlet temperature from the spray dryer was a key factor in simultaneous NO{sub x}/SO{sub x} removal. Above 190{degree}F, a relationship for NO{sub x} removal was found between the equivalence ratio of the reactants and the pollutants, the thickness of the filter cake, and the ratio of SO{sub x} to NO{sub x} at the system entrance. The existence of temperature window'' ideal for NO{sub x} removal could not be verified during the field tests, primarily due to an upper temperature limit of 210-215{degree}F. Also, as the filter-cake thickness increased, so did NO{sub x} removal. NO{sub x} removal (up to 45%) was enhanced by high ratios of SO{sub x}/NO{sub x} (>5:1) in the flue gas. At low SO{sub x}/NO{sub x} ratios (<2:1), virtually no NO{sub x} removal (<10%) took place, even when SO{sub x} removal was well over 90%. 15 refs., 29 figs., 16 tabs.

• Research Organization: Argonne National Lab., IL (USA). Energy Systems Div.
• Sponsoring Organization: DOE/FE
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7126788
• Report Number(s): ANL/ESD-6; ON: DE90010383
• Country of Publication: United States
• Language: English

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ADDITIVES
ALKALI METAL COMPOUNDS
CARBONACEOUS MATERIALS
CHALCOGENIDES
COAL
COMBINED SOXNOX PROCESSES
COMBUSTION PRODUCTS
CONTROL
CORRELATIONS
CRYSTAL STRUCTURE
DOCUMENT TYPES
DRYING
ENERGY SOURCES
EVALUATION
FABRIC FILTERS
FILTERS
FLUE GAS
FOSSIL FUELS
FOSSIL-FUEL POWER PLANTS
FUELS
GASEOUS WASTES
HYDROGEN COMPOUNDS
HYDROXIDES
MATERIALS
MICROSTRUCTURE
NITRATES
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
POROSITY
POWDERS
POWER PLANTS
PROGRESS REPORT
SODIUM COMPOUNDS
SODIUM HYDROXIDES
SORPTION
SPRAY DRYING
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
TEMPERATURE EFFECTS
THERMAL POWER PLANTS
WASTES