Boiler
MACT
National
Emission Standards for Hazardous Air Pollutants for Industrial,
Commercial, and Institutional Boilers and Process Heaters
Rule (40 CFR Part 63) Fact Sheet
The
Environmental Protection Agency (EPA) approved final rules Feb.
26, 2004, setting hazardous air pollutant emissions limits for
four industrial source categories, including large industrial
boilers. The so-called "Boiler MACT" is one of two
of the standards that contain risk-based exemptions.
EPA is required under Section 112 of the Clean Air Act to set
emissions limits for listed hazardous air pollutants at major
sources. The limits are based on maximum achievable control
technology (MACT) defined as the average performance of the
best-performing 12 percent of sources in a source category.
Under the risk-based approach EPA is providing alternative compliance
options in certain cases where the risks posed by the emissions
are very small. To qualify for these alternative approaches,
the industrial source in question would have to demonstrate
that the risks are small. Facilities that qualify for the alternative
compliance options must assume federally enforceable emissions
limitations. These limits ensure that their air toxics emissions
do not exceed levels used to qualify for the compliance alternative.
The final industrial boiler MACT includes an alternative compliance
option based on threshold emission limits for hydrogen chloride
(HCl) and manganese. If an owner or operator demonstrates that
their boiler units can meet health based threshold emission
limits, then EPA will assert that those units do not pose a
significant risk to human health or the environment.
The final rule provides the following three ways a facility
may demonstrate that a boiler or process heater meets the threshold
emission limits that allow it to qualify for the compliance
alternative:
1. "Lookup tables" - listed in the rule and posted
on the internet - allow facilities to use a limited number
of site-specific input parameters to determine whether emissions
from boilers or process heaters might cause a hazard index limit
for non-carcinogens to be exceeded.
2. Modeling - Facilities may demonstrate by modeling, using
site-specific information that emissions of a combination of
threshold pollutants such as HCl from the boiler or process
heater under evaluation do not cause a hazard index limit to
be exceeded.
(Note: Facilities that meet either of the first two alternative
compliance tests would not be required to install scrubbers
to control certain air toxics emissions. These boilers or process
heaters may be required to install fabric filters to reduce
particle emissions for a separate particle standard for boilers.)
3. Dried Wood - Boilers or process heaters fueled by dried
wood may, via a similar eligibility test, exclude emissions
of manganese from their calculation of total metals emitted.
This total is used to determine if particulate matter emissions
controls are required. These units may still be required to
install other emissions controls.
What
is the affected source?
- All existing industrial, commercial, and institutional
boilers and process heaters within a subcategory located at
a major source
- New or reconstructed industrial, commercial or institutional
boilers and process heaters located at a major source."
- EPA defines a process heater as, "an enclosed
device using controlled flame, that is not a boiler, and the
unit's primary purpose is to transfer heat indirectly to a
process material (liquid, gas, or solid) or to heat a transfer
material for use in a process unit, instead of generating
steam. Process heaters are devices in which the combustion
gases do not directly come in contact with process materials"
- EPA defines a boiler as, "an enclosed device
using controlled flame combustion and having the primary purpose
of recovering thermal energy in the form of steam or hot water"
What
types of units are exempt?
- Municipal waste combustors subject to 40 CFR Part
60, Subpart AAAA, Subpart BBBB, or Subpart Cb
- Hospital/medical/infectious waste incinerators subject
to 40 CFR Part 60, Subpart Ce or Subpart Ec
- Commercial and industrial solid waste incinerators
subject to 40 CFR Part 60, Subpart CCCC or Subpart DDDD
- Boilers or process heaters that are required to have
a permit under section 3005 of the Solid Waste Disposal Act
or hazardous waste boilers subject to 40 CFR Part 60, Subpart
EEE
- Recovery boilers or furnaces subject to 40 CFR Part
63, Subpart MM
- Refining kettles subject to 40 CFR Part 63, Subpart
X
- Ethylene cracking furnaces subject to 40 CFR Part
63, Subpart YY
- Any boiler or process heater that is or will be listed
as an affected source in another MACT standard
- Process heaters used for comfort or space heat
- Process heaters used for food preparation for on-site
consumption
- Autoclaves
- Waste heat boilers that do not incorporate duct or
supplemental burners and are designed to supply less than
50% of their total rated heat input capacity
- Hot water heaters with a capacity not exceeding 120
U. S. gallons, pressure not exceeding 160 pounds per square
inch gauge, and water temperatures not exceeding 210°
Fahrenheit (99 degrees Celsius)
- Temporary boilers that are capable of being moved
and which remain at any one location for less than 180 consecutive
days
- Boilers and process heaters used specifically for
research and development, whose sole purpose is not to provide
steam to a process at a research and development facility
- Blast furnace stoves described in the EPA document,
"National Emission Standards for Hazardous Air Pollutants
for Integrated Iron and Steel Plants - Background Information
for Proposed Standards, " (EPA-453/R-01-005)
- Any boiler or heater listed as an affected source
in another standard established under section 129 of the Clean
Air Act
- Blast furnace gas fuel-fired boilers and process
heaters that receive 90 percent or more of its total heat
input (based on an annual average) from blast furnace gas
- Electric utility steam generating units that are
fossil fuel-fired and supplies more than one-third of its
potential electrical output capacity and more than 25 megawatts
electrical output to any utility power distribution system
for sale
What
is the timeline for compliance?
- New or reconstructed boilers and process heaters
must comply by February 26, 2004 or upon startup, whichever
is later
- Existing boilers and process heaters must comply
by February 26, 2007
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