Making Sense of MACT: An Analysis of the Anticipated Iron and Steel Foundry Standards.

The MACT standards could require foundries to significantly enhance their emission controls, and this year's AFS Environmental, Health & Safety Conference looked at the impact of these potential regulations.

The Maximum Achievable Control Technology (MACT) standards for reducing emissions of Hazardous Air Pollutants (HAP) could affect the operations of many iron and steel foundries. Because of its significance, the topic dominated the 13th AFS Environmental, Health & Safety Conference.

Foundry representatives gathered in Indianapolis August 19-22 for the conference. The 119 registrants attended presentations by 27 speakers covering a range of topics from foundry/local government relations to multi-media inspections. Throughout these presentations, the anticipated MACT standards commanded the spotlight.

Expected to be in the 90-day comment period by August, the standards continue to hang in limbo in EPA's Office of General Counsel (OGC). Presentations offered conference attendees information on the possible content of the standards and their affect on various foundry processes.

MACT Update

Gary Masher, AFS vice president of environmental, health and safety, offered several ideas of what to expect from the final iron and steel MACT standards. He explained that the proposal was expected to be in the Federal Register by late September to kick off the 90-day comment period from foundries (as of November 15, it still wasn't). After the comment period, "the final standards must be defined by May 15, 2002, or the entire program will proceed on a case-by-case basis," Mosher said. This would free state EPA agencies to promulgate their own versions of the standards.

Once the standards are in place, said Mosher, foundries will have up to three years to comply. Mosher then described what foundries may expect from the standards based on conversations with the EPA staff working on the rule. He explained that the MACT standards will focus on the concentrations of emissions (particulate matter) emitted from foundry processes and will be based on the performance of baghouse technology.

The standards will apply only to major sources of emissions, defined as a site that produces more than 10 tons/yr of a single HAP or more than 25 tons/yr of all HAPs, regardless of process.

Furnaces Under Fire

Foundries that qualify as major sources will face various requirements based on their furnace type.

Jeet Radia, RMT, Inc., Columbus, Ohio, produced statistics on existing furnace emission control methods based on a survey conducted by U.S. EPA. In a survey of melting furnaces, most cupolas use a combination of an afterburner with a fabric filter or wet scrubber. Induction furnaces surveyed indicate that 57% have no air pollution control device (APCD) and 38% use a fabric filter.

Mosher detailed the possible standards requirements for these different types of melting furnaces. Existing cupolas would need to achieve 0.005 grains/dry standard cu ft of air (gr/dscf), run afterburners at 1300F (704C) and have an afterburner ramp up time of 30 min or however long the blast was off (whichever is shorter). New cupolas face more stringent requirements--they must achieve 0.003 gr/dscf of air, which essentially eliminates wet scrubbers as a control method, said Mosher.

He expects that induction and electric arc furnaces will have to achieve 0.005 gr/dscf if they have a capture system that is vented through a stack. Foundries using a scrap pre-heater will have to employ direct flame impingement or an afterburner operating at 800F (427C) on that process.

As the EPA researched potential emission limits for cupolas, it zeroed in on the 0.005 gr/dscf standard, Radia explained. EPA based this standard on test results from several relatively new cupola installations with fabric filters that achieved emission levels at or below 0.005 gr/dscf. This number is not an average of the emission levels from all cupolas--it is the average of the emission levels achieved in practice by the best controlled cupolas. This approach makes no allowance for deterioration in system performance over time that is known to occur in practice.

In addition to performance concerns, cost is an issue. While cost cannot be taken into consideration by EPA, Radia stressed, it plays a substantial role for foundries. For the 33 foundries (26 cupolas) on EPA's current list of major sources, the estimated capital cost for conversion is $288 million, with an annualized cost of $25 million. For the 109 foundries (84 cupolas) on EPA's original list of major sources, the estimated capital cost for conversion is $379 million, with an annualized cost of $67 million.

Pouring, Cooling and Shakeout Changes

Mosher stressed that melting is not the only foundry process that will be affected by the standards--pouring, cooling and shakeout may also face changes. Craig Schmeisser, RMT, Inc., stated that 1600 pouring and cooling lines have been identified, and less than 15% are controlled by an APCD. Of 1000 shakeout lines identified, over 50% had fabric filters. However, based on limited test data, a significant portion of them are not likely to meet the new standards.

The current expected particulates limit for existing pouring, cooling and shakeout lines is 0.01 gr/dscf, which wet scrubbers could meet, Mosher said. However, reports continue that the new standards may be 0.005 gr/dscf for emissions captured and vented through the roof--lower than what wet scrubbers can meet. This emission level will make baghouses necessary.

To better explain how MACT could affect pouring, cooling and shakeout lines, Schmeisser pointed out key words that were recommended by the AFS MACT Task Force (AFS-MTF) to EPA. He noted that an exhaust stream would likely be defined as "the gases emitted from a process that by design are captured, conveyed through ductwork and exhausted from the foundry through a stack using forced ventilation."

He expalined that when considering emission controls requirements for pouring and cooling lines, the key words are "if captured" and "flow-weighted average." If a capture system is not present, no emission limit applies. However, if there is capture, foundries "need a control device to meet 0.005 gr/dscf as a flow weighted average for pouring, cooling and shakeout exhausts," Schmeisser said.

Flow-weighted averages are based on the CFMs of pouring, cooling and shakeout emissions averages. They allow foundries to be compliant with MACT even if emissions from one process are above the emission limit. To comply, another process' emissions must be lower, averaging out the total emissions below the standards.

Adjusting Binders and Coatings

The MACT standards will affect more than molten metal processes--they probably also will regulate sand binders and coatings. Jonathan Stone, HA International, LLC, Westmont, Illinois, discussed the necessary reduction of methanol used in binders and coatings, the use of naphthalene-depleted solvents and the use of amine scrubbers.

Stone talked about the elimination of methanol from warmbox systems--methanol is a common carrier for the catalyst component and potentially will no longer be allowed. Changes to the resin will require resin manufacturers to reformulate to where less than 1% of methanol is on the Material Safety Data Sheet (MSDS). Also, foundries will have to switch to water-based catalyst systems.

Naplithalene-depleted solvent is not the perfect solution, warned Stone. No change has been seen performancewise, but availability and cost are big question marks. Naphthalene-depleted solvent costs more than conventional hydrocarbon solvents, increasing foundry costs.

More so than cost, the biggest problem facing the industry is availability. Not enough raw material exists today to make all the necessary switchovers. In addition, because of the demand to reduce naphthalene in all industries, naphthalene-depleted solvent replacements will be at even more of a premium. The pesticide industry, which also requires these replacements, commands higher margins than the foundry industry, and could outbid the resin manufacturers for the limited market supply.

The standards also will affect phenolic urethane coldbox systems. Foundries that use triethylamine (TEA) will need amine scrubbers, but those that use dimethylethylamine (DMEA) will not, Stone said. TEA users will have to maintain their scrubbers to manufacturers' specifications to meet the 1-3 ppm TEA regulations. EPA is concerned that some foundries may convert to DMEA to avoid the standards. However, Stone said that is unlikely because DMEA is harder to use--it is more volatile, more flammable, more corrosive and more expensive than its TEA counterpart. He also suggested that the regulations restricting use of TEA may open the U.S. market to some alternative amines used in Europe such as dimethylpropylamine and dimethylisopropylamine.

Exhaust airstream from any chemically-bonded mold must go through a thermal oxidation afterburner at 1500F (816C). According to Mosher, this negates the goal of using new low-emission binder technology because the foundry would have to add an afterburner even though the emissions are low.

Not only will the MACT standards affect binders, Stone said, they also will affect coatings. Most coatings contain trace levels of methanol. The methanol level will have to be limited to less than 1% so that it doesn't appear on the MSDS. In addition, methanol can no longer be used as a carrier in solventbased coatings-only isopropyl alcohol and naphtha will be used.

Mosher stated that much of the burden of the standards regarding core and moldmaking will fall on industry suppliers. Washes will not be allowed to contain liquid or gaseous HAPs, and methanol cannot be an identified ingredient in furan warmbox binders. The standards may dictate that naphthalene-depleted solvents be used in phenolic urethane binders and may require a 2 ppm emission limit for TEA at the outlet of a control device.

Next Steps

As the OGC reviews the standards and EPA makes its final decisions, several issues still remain in question. The AFS-MTF is trying to have steel foundries delisted as a major source category. Also up for debate is the number of steel facilities that fall under these standards. The EPA has estimated that 41 facilities maybe impacted by the standards based on utilization. MTF has calculated the number to be a minimum of 84 facilities based on potential to emit. The difference between these estimates stems from the variations in foundries' potential to emit versus their actual production rates.

Once EPA finalizes its proposed standards and specifies which industries and facilities must comply, it must allow for a 90-day comment period. During this time, it is the responsibility of individual foundries to examine the proposal and file comments with EPA expressing viewpoints and detailing the impact of the standards in their plant. According to Mosher, the standards are expected to be published and enter the comment period before the end of the first quarter of 2002.

RELATED ARTICLES: Monitoring, Record-Keeping and Reporting Requirements

Once the MACT standards are in place, foundries will need to track their emissions. The MACT standards pull from the National Emissions Standards for HAP (NESHAP) to fulfill emission tracking requirements. Phillip Gray, Citation Corp., Birmingham, Alabama, discussed these monitoring, record-keeping and reporting requirements for the new standards.

He explained that baghouses require monitoring through bag leak detection systems that have an alarm and provide the output of relative changes in particulate loading because the facilities need to establish a baseline that accounts for cleaning cycle spikes. The system does not have to read continuously- it is for leak detection, not for grain loading measurement.

Some of the information that a facility should monitor on baghouse systems includes:

* pressure drops across baghouses (low pressure reading indicates broken bags; high pressure reading indicates blinded bags and decreased airflow);

* operation of cleaning cycle and cleaning mechanism in the baghouse (including timer, cleaning cycle duration, dwell time, shakers and diaphragm valves);

* compressed air supply (pressure and the presence of water or oil);

* operation of the dust removal system (screw conveyors, rotary valves and dump valves);

* bag tension (specifically on shaker and reverse air baghouses);

* physical condition of the baghouse (corrosion of housing and tube sheets and access door seal condition).

Gray also listed monitoring requirements for wet scrubbers and cupolas. Wet scrubbers need to be monitored for pressure drops across the scrubber and for particulate matter control (monitor water flow rate or, for amine control, monitor the average liquid flow rate). Cupolas require monitoring of the ignition zone temperature, targeted to ensure a specified minimum temperature in the stack, and of the bast air status, the time on blast versus the temperature in the stack to ensure that a specified temperature is maintained when not on blast. Gray mentioned general requirements, such as keeping equipment clean and operational to avoid erroneous readings from buildup.

Monitoring amounts to increased paperwork and more detailed procedures, culminating in record-keeping and reporting. According to the general record-keeping requirements of NESHAP the records shall be in a form that is "suitable and readily available for expeditious inspection and review" and must be retained for at least 5 yr-with the most recent two kept onsite.

The requirements of the NESHAP standards, 40 CFR 63.10, cover a lot of ground but remain general, said Gray. Record-keeping requires maintaining records to show continuous compliance with emission limitations, but does not detail how to show continuous compliance. Records can include production records such as tons melted; hours operated and paint, solvent, coremaking chemical, fuel and coke usage.

Gray concluded by saying that the MACT standards will consolidate many of the monitoring, record-keeping and reporting requirements covered by existing air permits. "Most foundries are probably fulfilling a lot of these requirements in one form or another-this just compiles them all into one list "