CIBO-EPA Meeting

March 17, 2014

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Agenda- Subpart DDDDD Focus

• Coal fired boiler CO emissions relative to 

compliance and MATS approach

• Startup/shutdown requirements and major 

issues

• Potential impact and intentions relative to UPL 

application and remand

• Remand-reconsideration-compliance concerns

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CO DDDDD vs. MATS

• Essentially no difference in non-dioxin organic 

HAP emissions from coal fired ICI boilers 

compared to EGU boilers

– Basic combustion methods, fuels, operation are 

similar relative to non-dioxin organic HAP 

emissions

– Total emissions as TPY are much higher for EGU 

coal fired boilers than for ICI coal fired boilers

• Yet DDDDD imposes CO limits whereas MATS 

uses work practice approach

3
Issues with Boiler MACT CO Approach

• Concerns with asserting continuous 

compliance under all operating conditions

– CO emissions are known to vary with operating 

conditions and fuel quality (e.g., especially 

moisture and fines with stokers) over time 

– 30 day rolling average for CEMS may not cover 

issues

• Some boilers with inherent design limitations 

that impact CO emissions

4
Data Availability

• EPA made publicly available the following:

– Utility MATS proposed rule dated May 3, 2011

• Incorporating a work practice approach to address nondioxin organic HAP

– Results of the EPA pilot scale Multipollutant

Control Research Facility testing referenced in the 

MATS proposed rule

• Both arose after the close of comment period 

for the June 4, 2010 Boiler MACT Proposed 

Rule (August 23, 2010)

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Industrial Coal Boiler HCHO vs CO

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EGU Coal Boiler HCHO vs CO

7
Combined ICI Coal Boiler and EGU Coal 

Boiler Data

8
9
Conclusions

• A work practice approach as used for MATS coal fired boilers is 

equally applicable to ICI coal fired boilers

• Because the MATS work practice approach was first noticed after 

comment closing for the 2010 Boiler MACT Proposed rule, that 

approach was not available for public comment on the Boiler MACT 

rule

• Therefore, the work practice approach for coal fired boiler nondioxin organic HAP should be open for EPA reconsideration and 

included within EPA’s reconsideration of non-dioxin organic HAP 

emissions and CO limits

• This approach would retain all issues relative to coal fired ICI boiler 

CO within the reconsideration process and not split it between 

Court Review Briefs and reconsideration

– Resulting in a more coherent and efficient regulatory/legal process

• EPA could evaluate a mix of work practices as an alternative to CO 

limits

– Periodic tune-ups with ongoing continuous O2 monitoring

– O2 trim systems, which provide continuous combustion optimization

10
Startup/Shutdown Issues

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Operational Problems

• As discussed in CIBO (and others’) reconsideration 

petitions, there are major problems with the final rule 

startup/shutdown approach

• EPA’s MATS approach using percent load and time is 

reasonable

– 25% load for 4 hours following a cold start would work for 

a high percent of ICI units

– Those with remaining issues could be allowed to work out 

a unit-specific procedure with the permitting authority

• Examples of problems and recommended solutions 

provided separately & summarized in following slides

• These issues need to be addressed soon in the 

reconsideration process- there are serious concerns at 

the regulated sources whether additional provisions 

need to be provided 12
Scenario- startup on clean fuel, engage non-listed controls prior 

to adding solid fuel

Controls- Any 

• Potential compliance issue

– Clean fuel availability

– CO issue with transition from gas/liquid to solid

• 30 day average depends on compliance margin

• Suggested solution

– Expand clean fuel list

• Additionally, include all other Gas 1 fuels; biodiesel; fuels meeting HCl, Hg, 

TSM by fuel analysis; other clean fuels per permitting authorities

– Provide adequate “startup” time to cover transition from startup fuel 

to primary solid fuel per slides below

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Scenario- Startup on solid fuel

Controls- Dry 

• Potential compliance issues

– Need adequate flue gas temperature and low enough O2 prior to ESP 

energization

– Need time within “startup” period for combustion unit firing primary 

fuel(s) and all exempted air pollution controls to reach stable conditions

– Need “startup” definition to accommodate units with heat or steam 

upon main fuel ignition

– Differentiate between cold start (more time) & hot restart (less time)

• Suggested solutions

– Include ESPs in Table 3, item 5- exempted controls to be started as 

expeditiously as possible

– End startup when boiler/PH has continuously maintained ≥25% of 

maximum output at normal output conditions for 4 hr for cold start/1 hr 

for hot restart and all control devices in stable operation

– OR boiler/PH operating above minimum operationally stable output flow 

rate/pressure for minimum time per site-specific start-up plan 

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Scenario- Startup on solid fuel

Controls- Wet

• Potential compliance issues

– Need time within “startup” period for combustion unit firing primary 

fuel(s) and all exempted air pollution controls to reach stable conditions

– Differentiate between cold start (more time) & hot restart (less time)

– Could have problems meeting 30 day rolling CO CEMS limit if inadequate 

“startup” period is allowed

• Suggested solutions

– End startup when boiler/PH has continuously maintained ≥25% of 

maximum output at normal output conditions for 4 hr for cold start/1 hr 

for hot restart and all control devices in stable operation

– OR boiler/PH operating above minimum operationally stable output flow 

rate/pressure for minimum time per site-specific start-up plan 

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Scenario- Startup on solid fuel

Controls- Dry or Wet

• Potential compliance issues

– Need to address units that share common control device and startup 

sequentially or when one unit is starting up and one or more units is 

already in normal operation

– Could have problems meeting 24 hour block opacity limit or 30 day rolling 

CO CEMS limit if inadequate “startup” period is allowed

• Suggested solutions

– Sequential startup: End startup when the last boiler/PH to start has 

continuously maintained ≥25% of maximum output at normal output 

conditions for 4 hr for cold start/1 hr for hot restart and all control 

devices in stable operation

– OR when the last boiler/PH is operating above minimum operationally 

stable output flow rate/pressure for minimum time per site-specific startup plan 

– Non-sequential startup: The boiler/PH initiating startup would get a 

startup period with end of startup depending on hot/cold startup

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Scenario- Unit begins startup, reaches minimum stable load, but 

equipment problem results in “failed startup”

Controls- Any

• Potential compliance issues

– All of the above

• Suggested solutions

– Ensure entire period is considered startup, even if reach the minimum 

load threshold

– 4 hour period must be continuous

• To allow for recovery from decrease in temperatures, etc., to stable conditions

• Would not be able to continually cycle in and out of the startup period

• Once 25% load is reached for some time period, it becomes a hot restart

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Scenario- Lose solid fuel feed; delay or lack of auxiliary fuel; wet 

fuel can increase O2 and trip ESP, which trips fuel; fuel feed 

problems causing interruptions

Controls- Wet

• Potential compliance issues

– “Shutdown” not completed if unit continues to supply useful output until 

feed is restored

• Not normal operation and not always malfunction

– May be issue with 30-day CO CEMS limit depending on compliance margin 

and length of event

• Suggested solutions

– “Shutdown” definition to accommodate return of fuel prior to total loss of 

steam/heat output

• Cannot be forced to take unit totally down before reinitiating startup

• End of period would be a hot restart with startup work practices applying

– Revise to read: “Shutdown ends when there is both no steam or heat being 

supplied and no fuel being combusted in the boiler or process heater; or

when startup is initiated by reintroducing fuel to the boiler or process heater 

after fuel feed has been halted.”

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Scenario- Lose solid fuel feed; delay or lack of auxiliary fuel; wet 

fuel can increase O2 and trip ESP, which trips fuel; fuel feed 

problems causing interruptions

Controls- Dry

• Potential compliance issues

– “Shutdown” not completed if unit continues to supply useful output until 

feed is restored

• Not normal operation and not always malfunction

– ESP trip is required upon Master Fuel Trip

– May be issue with 24 hour block opacity limit or 30-day CO CEMS limit 

depending on compliance margin and length of event

• Suggested solutions

– “Shutdown” definition accommodate return of fuel prior to total loss of 

steam/heat output

• Cannot be forced to take unit totally down before reinitiating startup

• End of period would be a hot restart with startup work practices applying

– Revise to read: “Shutdown ends when there is both no steam or heat being 

supplied and no fuel being combusted in the boiler or process heater; or

when startup is initiated by reintroducing fuel to the boiler or process heater 

after fuel feed has been halted.”

– Include ESPs in Table 3, item 6 exempted APCs not required to be operated 

during a shutdown

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Scenario- Per the “shutdown” definition, shutdown begins upon 

halting fuel feed to the boiler/PH; fuel can still be burning in the 

boiler/PH

Controls- Any

• Potential compliance issues

– Current definition: 

• “Shutdown means the cessation of operation of a boiler or process heater for any 

purpose. Shutdown begins either when none of the steam from the boiler is supplied 

for heating and/or producing electricity, or for any other purpose, or at the point of no 

fuel being fired in the boiler or process heater, whichever is earlier. Shutdown ends 

when there is no steam and no heat being supplied and no fuel being fired in the boiler 

or process heater.”

– This can be interpreted that shutdown does not begin until no fuel is 

burning or no steam/heat is being supplied

– In some designs, fuel continues to burn in the unit after fuel feed stops

• Suggested solution

– Clarify that “fuel being fired” in this case means fuel being fed to the 

combustion unit

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Scenario- More than 1 unit vents to a wet control device; 1 unit 

shuts down and other(s) remain operating

Controls- Any

• Potential compliance issues

– Wet scrubber pressure drop can depend on flow through the scrubber

– With fewer units operating, operating parameter limits established 

during the performance test with both units in operation may not be 

achievable

• Suggested solution

– Unsure how to address in the rule

• Submit alternate monitoring request and establish different operating scenarios?

– e.g., alternate operating limits with fewer units in operation

– Similar issue to use of gas fuel firing in a solid fuel fired boiler where 

emission controls are not needed

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Path Forward

• EPA intentions to address startup/shutdown 

issues?

• Any further information needed?

22
UPL Implications

• Major concerns with delays and potential 

standard changes relative to compliance dates

• EPA intentions?

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Remand-Reconsideration-Compliance 

Concerns

• If any emission limit changes are 

contemplated, notice and comment is 

required along with extended compliance 

timing

• Compliance planning and capital investment 

must consider all regulatory requirements 

together

– ANY changes upset the process and cause timing, 

effort, and cost problems

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Additional discussion?

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