### MARYLAND DEPARTMENT OF THE ENVIRONMENT 1800 Washington Boulevard • Baltimore MD 21230 

## vtDE 410-537-3000 • 1-800-633-6101

Robert L. Ehrlich, Jr. Kendi P. Philbrick Governor Secretary 

## TECHNICAL SUPPORT DOCUMENT AMENDMENTS TO COMAR 26.11.10 CONTROL OF CARBON MONOXIDE EMISSIONS FROM BASIC OXYGEN FURNACES Background Carbon Monoxide (CO) is generated in relatively large quantities inbasic oxygen furnaces 

### ( BOFs 

### ) located at steel mills. BOFs contain hot metal from the blast furnace and scrap metal which is heatedwith oxygen to produce moltenmetal

. The molten metal is ultimately cast into steel slabs. The BOFs are equipped with a gas collection system orhoods thatexhaust the gases into a water scrubber systemthat is usedprimarily forcontrol ofparticulatematter. COMAR 26.11.10.06, Control ofCarbon Monoxide Emissions fromIron and Steel Installations (now withdrawn), required aperson who operated ablast furnace, grey iron cupola orBOF to burn the gas with excess oxygen atnot less than 1300 degrees F for at least 0.3 seconds in a direct flame afterburner. Thatregulation was withdrawnbecause: (1) blastfurnace gas is not controlledbutis used as fuel in on site fuel burning equipment; (2) there are no grey iron cupolas located at steel mills and cupolas notlocated at steel mills are subjectto the carbon monoxide emissions requirements in COMAR26.11.06 and (3) carbon monoxide emissions fromBOFs are not controlled in that manner. When the furnaces are operating, the flames extend into the hood and incinerate the carbon monoxide before it is exhausted through the scrubbers. Purpose ofAmendment This amendment re-establishes a carbon monoxide standard forBOFs located at steel mills. Affected sources must demonstrate that the carbon monoxide concentration in the gas stream does not exceed 1 percent. Affected sources are required to demonstrate compliance by conducting an initial stack test and additional stack tests every 2.5 years. The 2.5 yeartest cycle provides a midpoint and end ofcycle test forthe five yearPart 70 permit. Affected Sources The only BOFs in Maryland are located at the Sparrows Point facility which was previously operated by Bethlehem Steel and is now operatedby International Steel Group (ISG). The BOF facility consists oftwo furnaces and four water scrubbers each discharging through a separate stack. According to the EPA emission factor and stack tests at other facilities,

RLcyLkd www m& state md us FTY Urs I 800 73) 22)8incineration ofcarbon monoxide in the furnace hoods is about 99 percent efficient. ReuIation Reguirements The affected source is requiredto perform stacktest to demonstrate compliance with the 1 percent emission standard. The affected facility operates two BOF that are equipped with four scnibbers each discharging into a separate stack. The facility can operate all four systems or any combination ofsystems. If, for example, three scrubber/stack systems were in operation, each stack is tested simultaneously for one hour. These three tests are considered atest run and are to be repeated two more times. The three simultaneous tests are totaled to determine the total CO forthat run. Compliance with the one percent standard is determinedby averaging three runs. Since aproduction cycle could be less than one hour it may be necessary to conduct arun during parts oftwo cycles. A CO test is required initially to demonstrate compliance. Thereafter, a CO test is performed eachtwo and ahalfyears. Afterthe initial test, the schedule may be adjusted so that the CO test is done during the period when otherpollutants are being tested at other sources within the facility. Economic Impact The BOF hooding was designedto effectively incinerate the carbon monoxide. Therefore, the 1 percentconcentration standard shouldbe metwithout any significantequipment modification. The final effluent, afterthe scrubbers, is dischargedthrough four stacks which are equippedwithportholes for stacktesting. A stacktest for carbon monoxide will cost approximately $25,000. Other State or Federal Requirements The EPA has finalized a maximum achievable control technology (MACT) standardthat applies to BOFs. Thatrule regulates toxic airpollutants but not carbon monoxide. The rule, however, may require affected sources to install additional hoods.

L:’AQPlanning and Monitoring\Regulation Development Division’Technical Support Documents (TSDs)\CO at Steel Mills (final) tsd.doc

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