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GCI TECH NOTES©

Volume 15, Number 4           A Gossman Consulting, Inc. Publication       September 2010

Portland Cement 2010 NESHAP Final Rule - Mercury

by

David Gossman

Introduction
On September 9, 2010, EPA published in the Federal Register new PC MACT regulations. Of the standards, the new mercury emission limits and monitoring requirements will be one of the most difficult to comply with.

Source	Operating Mode	Hg Limit	Units
Existing	Normal	55	lb/MM tons clinker
Existing	Startup & Shutdown	10	µg/dscm
New	Normal	21	lb/MM tons clinker
New	Startup & Shutdown	4	µg/dscm

•      Mercury CEMS or sorbent trap
•      First 30 days data determine initial compliance
•      Hourly production rate of clinker to be determined 63.1350(d)

•      Normal operation - Continuous compliance documented based on 30 day rolling average
•      Startup/shutdown - Continuous compliance documented based on 7 day rolling average

•      Hourly mercury emissions and stack gas flow rate data must be obtained.
•      Optionally, sorbent trap data is gathered daily.
•      Stack gas flow rate monitored in accordance with 40 CFR 63.1350(k)(4)
•      Note: Reporting units are specified in the rule as lb/million (lb/MM) tons of clinker.

            Mercury Monitoring Reporting
•      Nevertheless, this section specifies a span requirement that is different from PS 12A.
         - Needs to include upper limit for only normal “mill on” operation. 
         - Must also include 2 times the emission standard.

             Site Specific Monitoring Plans
            40 CFR 63.1350(p)
•      The New SSMP!
•      Different one required for each Continuous Monitoring System (CMS)
•      Must be available for submission at least 60 days prior to initial performance evaluation.

•      It does not detect particulate mercury!
•      Standards are elemental mercury and HgCl₂.
•      Mercury CEMS extraction point requires stack or duct – open top bag houses won’t comply.
•      While other options exist, Method 30A should be considered the method of choice for RATA.

             Interesting Items from Preamble - Mercury

•      Eleven (11) kilns were used to set MACT floor limits.
•      EPA acknowledges that the main source of variability is raw materials and fuel.
•      EPA is eliminating the restriction on the use of fly ash containing mercury.
•      EPA is also eliminating restrictions on the CKD waste rate.
•      ACI appears to be the only control technology EPA has thoroughly evaluated.
•      EPA, in developing the standard, assumed no kilns currently control mercury emissions.

            Mercury CEMS – Times Have Changed

•      One key was elimination of particulate bound mercury.
•      Numerous manufacturers – some include:
        –  TEKRAN
        –  PS Analytical
        –  CEMTREX
        –  SICK MAIHAK
        –  Thermo Scientific
        –  Nippon Instruments

            CEMS Calibration
•      Requires NIST traceable standards.
•      NIST only has elemental standards at 41-353 µg/dscm.
•      Limits of 4-10 µg/dscm require a span of 10-20 µg/dscm.
•      There are apparently NIST traceable elemental Hg generators that go down to 1 µg/dscm.
•      EPA will need to address this issue.

Conclusion:  A compliance strategy is clearly needed.

Step 1:

• Start early – get mercury CEMS now!
• Gain mercury CEMS operating experience.
• Check for compliance status over different operating conditions as well as during start-up and shut-down.

Step 2:

• If out of compliance, how far?
• If in compliance, how close?
• Evaluate need for operating flexibility.
• Identify sources of mercury in system.
• Speciate mercury in emmissions under different operating conditions.
• Can small changes in raw feed/fuel impact compliance?

 Step 3: 

• Develop slip stream bleed options and test.
• Evaluate if improvements in particulate control will impact mercury emissions.
• Investigate alternative/innovative technologies.
• Avoid ACI unless absolutely necessary!