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HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
The National Emission Standards for Hazardous Air Pollutants (NESHAP) for major and area source boilers and process heaters,
also known as the major and area source Boiler MACT rules, were enacted on January 31 and February 1, 2013, respectively,
and affects approximately 14,000 major source boilers and process heaters and approximately 183,000 area source boilers
nationwide. One of the specific requirements of the federal regulations require owners or operators to conduct a one-time
energy assessment through a Qualified Energy Assessor as defined in the rules. The intent of this effort is to identify credible
methods of conserving energy and reducing resources, which if implemented, directly relate to a measurable reduction in
emissions of hazardous air pollutants (HAPs) caused by the burning of fuels. While some may see this as a perfunctory effort to
satisfy a regulatory requirement, smart owners or operators will use this opportunity to attain significant improvements to safety,
production, and efficiency in an overall master plan built around sustainability.
BACKGROUND:
The Boiler MACT rules require owners or operators of affected boilers (and
process heaters for major source facilities) to conduct energy assessments
for the primary purpose of identifying energy savings opportunities that will
reduce overall air emissions. The energy assessments must be conducted by
March 21, 2014 for area sources and by January 31, 2016 for major sources.
RMF’s team of Boiler MACT inspectors and certified energy engineers have
evaluated hundreds of fuel burning plants and created plans for improving
thermal efficiencies by as much as 20 points by applying modern principles
of energy conservation. RMF is also an NB-369 Authorized Inspection Agency
(AIA) through the National Board of Boiler and Pressure Vessel Inspectors and
can examine plants for code compliance, safety, and reliability.
ENERGY ASSESSMENT REQUIREMENTS:
Key highlights of the 40 CFR Part 63, Subparts DDDDD (major source) and
JJJJJJ (area source) energy assessments include:
»» Assessments are required for existing sources (those constructed on or
before June 4, 2010) as follows:
• Area sources: existing liquid and solid fuel-fired boilers with a design
heat input capacity of 10 MMBtu/hr or greater, except limited-use
boilers
• Major sources: existing gas, liquid, and solid fuel-fired boilers with a
design heat input capacity of 10 MMBtu/hr or greater, except limiteduse boilers
»» It is a one-time assessment
»» It must be conducted by a qualified energy assessor
»» It must be completed by March 21, 2014 for area sources, and by January
31, 2016 for major sources
»» An energy assessment completed on or after January 1, 2008, that meets
or is amended to meet the energy assessment requirements in these rules,
or a source operating under an energy management system compatible
with ISO 50001 satisfies the energy assessment requirement
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]
HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
»» The purpose is to reduce facility energy demand
• Reduces operating and maintenance costs
• Decrease fuel use
• Decrease emissions of hazardous air pollutants (HAP) and non-HAP
»» Expectations - The Department of Energy conducted similar assessments at selected manufacturing facilities which yielded
10 -15% fuel reduction/energy use, plus corresponding emissions reductions
THE PROCESS
The energy assessment must include the following items:
1. A visual inspection of the boiler system (e.g. cracks, corrosion, leaks, insulation);
2. An evaluation of operating characteristics of the affected boiler systems, specifications of energy use systems, operating and
maintenance procedures, and unusual operating constraints;
3. An inventory of major systems consuming energy (i.e., energy use systems) from affected boiler(s) and which are under the
control of the boiler owner or operator;
4. A review of available architectural and engineering plans, facility operation and maintenance procedures and logs, and fuel
usage;
5. A review of the facility’s energy management practices with recommendations for improvements (major sources only);
6. A list of major energy conservation measures that are within the facility’s control;
7. A list of the energy savings potential of the energy conservation measures identified; and
8. A comprehensive report detailing the ways to improve efficiency, the cost of specific improvements, benefits, and the time
frame for recouping those investments.
DURATION OF ASSESSMENT
If your facility has Boiler Annual Heat
Input, as measured in Trillion Btu/yr
(Tbtu/yr), of…
Then the length of the energy
assessment, in on-site technical labor
hours*, need not exceed**…
And should include any on-site energy
use systems that account for this
percent of the energy production from
these affected boilers…
Less than 0.3
8 hours
At least 50%
0.3 to 1
24 hours
At least 33%
Greater than 1.0
24 hours for the first TBtu/yr plus 8
hours for every additional TBtu/yr, not
to exceed 160 hours
At least 20%
* The on-site technical hours are required for items 1 through 4 of the energy assessment.
** The length may be longer at the discretion of the owner or operator of the affected source.
Heat input capacity for each affected boiler is calculated based on 8,760 hours per year. For the purpose of determining which
heat input capacity thresholds and associated maximum on-site technology labor hours in the definition of “Energy assessment”
apply to the facility’s energy assessment, “combined heat input” is calculated by adding together the heat input capacity for each
boiler subject to the energy assessment requirement. The calculation differs between the Major Source Boilers Rule and the Area
Source Boilers Rule.
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]
HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
Specifically, under the Major Source Boilers Rule, all existing boilers are
subject to the energy assessment requirement so heat input capacity for
all existing boilers at a major source facility would be included in the
“combined heat input” calculation. Under the Area Source Boilers Rule, only
existing boilers with heat input capacity equal to and great than 10 MMBtu/
hr are subject to the energy assessment requirement so heat input capacity
for only those specific existing boilers at an area source facility would be
included in the “combined heat input” calculation.
For example, a facility consists of a single boiler that provides steam to
10 end uses with each end use accounting for about 10%. The facility has
a heat input capacity of less than 0.3 trillion Btu/yr. Therefore, the Boiler
MACT rules require an evaluation of the boiler systems and any on-site
energy use systems accounting for at least 50% of the affected boilers energy
production. In this example, only the boiler would need to be included in the
energy assessment since none of the end uses exceeds the 50% threshold.
Energy assessments must evaluate the:
»» Boiler system including the
1. Boiler; and associated components, such as, the feedwater
systems, combustion air systems, fuel systems (including burners),
blowdown systems, combustion control systems, steam systems,
and condensate return systems, directly connected to and serving
the energy use systems
»» Energy use systems (meeting energy production threshold)
1. Process heating; compressed air systems; machine drive (motors,
pumps, fans); process cooling; facility heating, ventilation, and air
conditioning systems; hot heater systems; building envelope, and
lighting; or other systems that use steam, hot water, process heat,
or electricity, provided by the affected boiler
2. Energy use systems are only those systems using energy clearly
produced by affected boilers.
TYPICAL CONSERVATION MEASURES:
The most promising types of cost effective improvements are often realized
by the following:
» Fuel (Primary Energy Source) Switching
»» Excess Air Control
»» Modern Combustion Controls
»» Blowdown Heat Recovery
»» Blowdown Reduction
»» Stack Economizers
»» Fuel Gas Condensing System
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]
HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
»»
»»
»»
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»»
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Combustion Air Preheaters
Water Treatment Scale Upgrades & Soot Reduction
Cogeneration / Steam Driven Auxiliaries
Steam Leak Repairs
Steam Trap Testing & Repair
Steam End-Use Management
Applied Steam Energy vs. Direct-Fired Energy vs. Electricity Conversion
Reinsulation
Manhole Rehabilitation and Insulation
Insulation Addition
Condensate Recovery
Steam Pressure Reduction
LOW COST-NO COST IMPROVEMENTS:
Why do we operate this way? “Well, it’s because that’s how it’s always
been” is a phrase that has shared by many operators when interviewed by
RMF’s assessment teams.
Standard operating procedures are necessary and are often prescribed in
established written manuals while others may be less regimented. Either
way it is most important to know why something is operated in a specific
way. Some of the most cost effective impacts can be realized just by changing
operating methods.
Case History - Connecticut Department of Public Works
During a recent assessment, RMF discovered a plant that was venting 10,000
to 20,000 PPH steam continuously since 1938 simply to keep a steady load
on its generating equipment and generate a modest amount of electrical
power. This procedure had been in place for over 70 years when residual
fuel oil was less than 20 cents per gallon and never challenged even when
the unit cost of fuel reached $4.00 per gallon. An energy assessment quickly
determined that the plant could turn the boiler and turbine off, purchase
from the utility provider the small amount of electricity it had been producing
on its own, and save over $300,000 per year and reduce greenhouse gases
by 1,800 tons per year.
Investment: $0 Return on Investment: Instantly
EXCESS AIR CONTROL
Excess air control occurs when there is more air for combustion than is
required to burn fuel in the boiler. The excess air is heated and released
through the stack to the atmosphere resulting in a loss of efficiency of as
much as 5% or more.
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]
HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
Too much excess air can occur because of a variety of factors:
»» The burner control system is out of tune
»» The air density fluctuates
»» The control system is primitive
»» The fuel composition varies
Excess air is identified by measuring the oxygen content in the flue gases.
Tuning can restore the proper level, else modern oxygen trim kits can be
evaluated for implementation. In past tests, some boilers that were found
operating at as much as 120% excess air levels resulting in significant energy
losses. On well operated systems, excess air levels of only 10% to 15% are
achievable depending on the type of fuel.
REDUCE BLOWDOWN
Continuous boiler blowdown is generally required to reduce the amount of
total dissolved solids (TDS) in the boiler feedwater that can cause scaling
of heat exchanger surfaces, tubes, drums, etc. Sometimes the blowdown
rate (%) is found to be higher than is necessary resulting in significant heat
(energy) being wasted to the sewer unless heat recovery equipment is in
place. A sound plan includes a review of the plant’s historical levels of TDS,
alkalinity, suspended solids and silica and determine if the blowdown rate
can be reduced.
CONDENSATE RECOVERY
Recovering hot condensate from a campus distribution system is a significant
way to improve overall system efficiency. Over 15% of a steam system’s
energy input can be lost to heating cold makeup water when no condensate
is returned. The goal is to achieve the highest condensate recovery rate
possible to maximize cycle efficiency.
STEAM PRESSURE REDUCTION
A steam supply pressure reduction at the boiler plant can sometimes result
in an efficiency gain of up to one percentage point. In most cases, pressure
reducing valve (PRV) stations are installed at building interfaces to reduce
the high pressure supply steam to a lower usable pressure within the
buildings. The high supply pressure is not always necessary for the short
transmission distances and ultimate use of the steam.
MAINTENANCE AND REPAIR:
The stewardship of plant and distribution system assets requires constant
diligence and can often be challenged by limited operating budgets. The
discovery phase of an energy assessment can help justify maintenance funds
that when applied to real life corrections yield immediate, positive results.
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]
HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
WATER TREATMENT / SCALE / SOOT
Scaling acts as an insulator on heat transfer surfaces. Poor water treatment
can result in the fouling of heat exchangers, tubes, drums etc with calcium,
silica, or magnesium. A 1/16” scale deposit can lower boiler efficiency by 6%.
Similarly, soot deposits can raise flue gas temperatures, resulting in more
heat lost in the stack. Removing and preventing heat exchanger fouling can
restore equipment to its original efficiency.
STEAM LEAKS
Steam leaks in older distribution piping systems are very common. Above
ground piping are often easily detected visually and can be repaired to
proper working order.
The result is a high economic return for a relatively low cost investment.
A single 1/16” pinhole in a steam system operating at 110 psig can release
several hundred thousand pounds of steam per year. Sometimes a 5%
efficiency gain can be realized when large steam leaks are identified and
repaired.
STEAM TRAP TESTING & REPAIR
The testing and maintenance of steam traps is essential for reducing energy
losses in steam heating systems. In the absence of a steam trap maintenance
program, it is common for 15% to 20% of a facility’s steam traps to be
malfunctioning. One defective trap can release 200,000 to 400,000 pounds
of steam per year. Energy efficiency gains of 10% to 15% are not uncommon
when proper attention is given to trap maintenance.
UNDERGROUND STEAM LEAKS
Infrared imaging equipment is used for aerial and land based infrared
thermal imaging to conduct campus areas of heat loss for above ground
and underground heat distribution systems. It identifies leaks, insulation
degradation, and corrosive attacks to underground piping systems for a
relatively low cost.
REINSULATION
Distribution heat loss can be reduced by reinsulating with high temperature
closed cell foam insulation inside conduits housing the underground
steam pipes on both built-in-place and drainable/dryable/testable systems.
A closed-cell foam material surrounds the pipes and seals out ground
water. The process can be performed while the steam system is operating,
eliminating the need to shut the system down. Heat loss reductions of as
much as 40% can be reduced for a fraction of the cost (10%) of replacing
underground lines.
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]
HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
MANHOLE REHABILITATION AND INSULATION
Many steam distribution systems yield poor delivery rates because the
underground manholes are flooded, uninsulated, or in poor mechanical
condition. Drainage can be accomplished by gravity or electric or steam
pressure powered pumps.
MODEST INVESTMENTS WITH BIG RETURNS:
Innovative methods of heat recovery and energy storage can be achieved by
using new technologies and exploring retrofit possibilities.
ECONOMIZERS
Heat is lost in the flue gases leaving the boiler. Often, it is feasible to install
a fuel economizer in the boiler stack that transfers the waste heat into
preheating boiler feedwater, thereby improving efficiency. Decreasing the
flue gas temperature by 40°F or raising the feedwater temperature by 11°F
results in a boiler efficiency increase of 1%.
PREHEAT COMBUSTION AIR
Air heaters on solid fuel boilers have long been an effective way to boost
efficiency. Another simple but effective way to improve boiler efficiency is
to utilize stratified air near the top of the boiler room for combustion air. A
40°F rise in combustion air temperature can result in a 1% efficiency gain.
CONDENSING ECONOMIZERS
When the principal fuel is natural gas or low sulfur oil, exceptionally low
stack temperatures can be reached (112°F) whereby more heat is transferred
to the feedwater.
Case history - Duke University
The West Campus Steam plant in Durham, NC has been in operation since
1928. In 2013, Duke renovated this facility and installed an innovative heat
recovery system which includes a condensing economizer to capture stack
gas heat that would otherwise be exhausted into the atmosphere. Recovered
energy is used to pre-heat makeup water and boost condensate temperature.
This single energy conservation investment has raised thermal efficiency
on Boilers 1 and 2 (80,000 PPH each) from 83% to 89%. The return on
investment is 3 years.
MODERN COMBUSTION CONTROLS
The replacement of antiquated control systems with modern microprocessor
based electronic control can result in improved combustion, lower excess
air, lower emissions, and elimination of boiler “cycling”. The goal would be
to operate boilers at peak efficiency points, resulting in typically 1 to 3 points
efficiency gain.
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]
HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
BLOWDOWN HEAT RECOVERY
Surface (continuous) boiler blowdown is commonly performed for the
purpose of elimination of the buildup of concentration of total dissolved
solids (TDS) in the boiler feedwater. A large amount of heat is lost when the
blowdown is discharged directly to the sanitary sewer system.
RMF’s approach to blowdown optimization is to first determine if the
blowdown rate (1%, 2%, 5%, etc.) is correct and second design a heat
recovery system which traditionally is comprised of a flash tank and a shell
and tube heat exchanger that transfers heat from the blowdown into the
incoming cold water makeup to the deaerator.
COGENERATION / STEAM DRIVEN EQUIPMENT
If the existing steam supply pressure is greater than is required to adequately
distribute steam to the base, either the operating pressure can be lowered
or possibly a backpressure turbogenerator can be installed to generate
electricity on site at the plant. At the very least, backpressure turbine
driven equipment (feedwater pumps, fans, etc.) is highly recommended
for consideration, since low pressure steam is required in the deaerator for
feedwater heating.
Case History - Bowdoin College
Bowdoin College reconfigured its heating plant to be a Combined Heat and
Power (CHP) system with a new 60,000 pph boiler, 630 kW backpressure
turbine generator, and auxiliaries designed for an operating pressure at 240
psig. The work has been constructed and placed into operation. Bowdoin
generates approximately 1 million kW per year of electricity on site.
INSULATION
Steam and condensate piping, equipment, valves, and fittings operate at
elevated temperatures and require tight insulation for minimizing convective
heat losses. Moisture resistant removable blankets can be a very effective
method of conserving heat from active piping and fittings.
POINT OF USE MODIFICATIONS
Sometimes a new cost effective solution may be available to meet the end
user’s needs without making major changes to the overall boiler system. It
is not unusual to find meaningful investments at the actual point of use by
different energy sources or additional equipment.
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]
HOW TO GET THE MOST OUT OF YOUR
MACT ENERGY ASSESSMENT
Case History - University of Southern Maine
For many years, the main central heat plant (1150 boiler horsepower
capacity, 5,000 LF piping loop) was continuously kept in operation all year
long to generate 300 F high temperature hot water. Its main function in
the summer was to serve the hot water needs at the Brooks Dining Hall
for food preparation and dishwashing. RMF recommended, designed, and
commissioned a small (1.34 MMBTU) satellite high efficiency gas fired heating
system at the dining center point of use to generate 1,380 PPH of steam at
13 PSIG. This allowed the main heating plant to be de-energized from May
to August and allowed the main loop supply temperature to be lowered
throughout the year, reducing energy waste, emissions and equipment wear.
MAXIMIZING BENEFITS - THE BIGGER PICTURE:
While the on-site energy assessment is focused on identifying discrete
methods of energy conservation, it provides an ideal opportunity to look
at code compliance, safety provisions, and operations as a whole. Several
universities are seizing this opportunity to create a master plan using the
recommendations for energy savings. The interest extends to CHP and
chilled water system efficiency improvements and modernization. A 20-year
roadmap of projects with budgets, schedules and implementation plans is
the greater product of these assessment for MACT compliance.
THE NEXT STEP:
The EPA MACT’s Area Source Rule Energy Assessment is a compulsory
requirement for boiler owners to have an independent review of the way
equipment is installed, operated, maintained, and how energy is consumed
and utilized on site. It requires a monetary investment and is time sensitive.
The assessment could end with a brief report without follow up action,
but smart owners are using it as the platform to really examine what they
own and operate, discover how well it is performing and how long it will
last, and finally plan methodically to make it more efficient, reliable, and
maintainable. The opportunity is yours to explore.
For further ideas and discussion on assessments, contact Brian Wodka, P.E.
CONTACT:
Brian Wodka, PE, CEM LEED AP
Reliability Engineer / Boiler Inspector
(800) 938-5760
[email protected]