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 in basic oxygen

furnaces ( BOFs ) located at steel mills. BOFs contain hot metal from the blast furnace and scrap

metal which is heated with oxygen to produce molten metal . The molten metal is ultimately cast

into steel slabs. The BOFs are equipped with a gas collection system or hoods that exhaust the

gases into a water scrubber system that is used primarily for control of particulate matter.

COMAR 26.11.10.06, Control of Carbon Monoxide Emissions from Iron and Steel

Installations (now withdrawn), required a person who operated a blast furnace, grey iron cupola

or BOF to burn the gas with excess oxygen at not less than 1300 degrees F for at least 0.3

seconds in a direct flame afterburner. That regulation was withdrawn because: (1) blast furnace

gas is not controlled but is used as fuel in on site fuel burning equipment; (2) there are no grey

iron cupolas located at steel mills and cupolas not located at steel mills are subject to the carbon

monoxide emissions requirements in COMAR 26.11.06 and (3) carbon monoxide emissions

from BOFs 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 of Amendment

This amendment re-establishes a carbon monoxide standard for BOFs 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 year test cycle

provides a mid point and end of cycle test for the five year Part 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 operated by International Steel Group (ISG).

The BOF facility consists of two furnaces and four water scrubbers each discharging through a

separate stack. According to the EPA emission factor and stack tests at other facilities,

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incineration of carbon monoxide in the furnace hoods is about 99 percent efficient.

ReuIation Reguirements

The affected source is required to perform stack test 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 of systems. If, for example, three scrubber/stack systems were in operation, each

stack is tested simultaneously for one hour. These three tests are considered a test run and are to

be repeated two more times. The three simultaneous tests are totaled to determine the total CO

for that run. Compliance with the one percent standard is determined by averaging three runs.

Since a production cycle could be less than one hour it may be necessary to conduct a run during

parts of two cycles.

A CO test is required initially to demonstrate compliance. Thereafter, a CO test is

performed each two and a half years. After the initial test, the schedule may be adjusted so that

the CO test is done during the period when other pollutants are being tested at other sources

within the facility.

Economic Impact

The BOF hooding was designed to effectively incinerate the carbon monoxide.

Therefore, the 1 percent concentration standard should be met without any significant equipment

modification. The final effluent, after the scrubbers, is discharged through four stacks which are

equipped with port holes for stack testing. A stack test for carbon monoxide will cost

approximately $25 ,000.

Other State or Federal Requirements

The EPA has finalized a maximum achievable control technology (MACT) standard that

applies to BOFs. That rule regulates toxic air pollutants 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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