Integrated boiler room controls can facilitate fuel monitoring and reporting and provide good payback in terms of energy savings.
In 2011, the EPA enacted the Area Source Rule, making it mandatory for many commercial, institutional and manufacturing facilities to monitor fuel usage on a monthly basis and conduct biennial tuneups. Some facilities also are required to conduct a one-time energy assessment, and others must regularly meet emissions limits.
The new rule applies to any area source facility, which includes the majority of facilities in the United States. An area source facility is one that emits less than 10 tons per year of any single air toxic and 25 tons or more per year of any combination of air toxics.
A comprehensive list of the regulated air toxics can be found on the EPA website at www.epa.gov. Methods for calculating a facility’s emissions are detailed in the “Preferred and Alternative Methods for Estimating Air Emissions from Boilers” guide, also available on the EPA site.
When the EPA proposed the Area Source Rule, the agency also proposed the Major Source Rule (also known as Boiler MACT or BMACT), designed to reduce boiler and process heater emissions at large sources of air toxics. Currently, the EPA is reconsidering parts of the Major Source and Area Source Rules. While it is carrying out the formal reconsideration process, the Area Source Rule is in effect. However, the Major Source Rule is delayed while the EPA reconsiders reconsiders it.
Factors that Determine Compliance Requirements
Compliance requirements for the Area Source Rule - many of which take effect in 2012 - vary depending upon the type of fuel burned, the size of the boiler and its age.
All area sources can be classified as one of the following fuel subcategories:
Biomass. Any boiler that burns at least 15 percent biomass on an annual heat input basis.
Coal. Any boiler that burns any solid fossil fuel and no more than 15 percent biomass on an annual heat input basis.
Oil. Any boiler that burns any liquid fuel and is not in either the biomass or coal subcategories.
- Gas-Fired. Any boiler that burns gaseous fuels, including natural gas, process gas, landfill gas, coal-derived gas, refinery gas, hydrogen or biogas, not combined with any solid fuels. To maintain status as a gas-fired boiler, periodic burning of a liquid fuel cannot exceed a combined total of 48 hours during any calendar year.
Boiler size, as it relates to the Area Source Rule, is expressed in terms of rated design heat input capacity and is measured in million British thermal units per hour, or MMBTU/hr. Boilers that are larger or equal to 10 MMBTU/hr input have different requirements than those that are smaller.
The age of a boiler also is a factor in determining compliance requirements. A boiler is considered an existing source if construction or reconstruction began on or before June 4, 2010. A boiler is considered a new source if: construction or reconstruction began after June 4, 2010, and the applicability criteria was met when construction started; or, the boiler switched from firing natural gas fuel to a solid fossil fuel, biomass, or liquid fuel after June 4, 2010.
Meeting Compliance Requirements
Under the new Area Source Rule, facilities must meter and record their fuel usage monthly. Fortunately, several products are available to help facilities monitor fuel usage. For instance, sophisticated control and monitoring systems work with an advanced supervisory control and data acquisition (SCADA) computer system to control a boiler’s room balance while gathering continuous, real-time data.
If an integrated boiler room control is not the best solution for your facility, another option to consider is a standalone transmitter that provides pertinent boiler information to a PC or server within a facility’s existing network. One particular system can monitor up to three fuels per boiler.
There also are monitoring systems available that collect fuel usage on boiler systems that are not equipped with intelligent controls. For example, one model gathers data for up to two fuels per boiler, utilizing a transmitter to send the information to a PC or facility network server.
Under the Area Source Rule, facilities must monitor fuel usage on a monthly basis and conduct biennial tuneups.
Conducting Boiler Tuneups
Another requirement of the EPA rules is a boiler tuneup, which must be conducted for all biomass- and oil-fired boilers as well as for new and existing coal-fired area source boilers with a heat input capacity of less than 10 MMBTU/hr.
For existing boilers, the first tuneup should be completed by March 21, 2012, and for new sources, the tuneup was to be done by May 20, 2011, or upon startup of the boiler, whichever is later. Subsequent tuneups are required every other year.
For the initial tuneup, the following steps are necessary:
Inspect the burner and clean or replace any components, as necessary.
Adjust the burner as necessary to optimize the flame pattern.
Inspect the air-to-fuel ratio control system to ensure it is calibrated and functioning properly.
Optimize emissions of carbon monoxide (CO) consistent with manufacturer’s specifications, if available.
Measure CO and O2 levels in exhaust before and after tuneup.
Record the type and amount of fuel used for previous 12 months (the effective date of the rule was May 20, 2011, so the first tuneup will have less than 12 months of reporting).
- Submit a signed statement indicating that a boiler tuneup was completed.
The same steps are required for subsequent tuneups. The compliance certificates should be kept at the facility and submitted upon request.
Arranging an Energy Assessment
For large, existing biomass-, oil- and coal-fired boilers, a one-time energy assessment is required under the Area Source Rule. The assessment must be performed by a qualified energy assessor and should include:
Visual inspection of the boiler system.
An evaluation of operating characteristics of the facility.
An inventory of major systems consuming energy away from affected boiler(s).
A review of architectural and engineering plans, facility operation and maintenance.
A list of major energy conservation measures.
A list of energy savings potential.
- A report detailing ways to improve efficiency.
A facility must keep the results of the energy assessment on site for submission when requested.
Meeting Emissions Limits
Under the Area Source Rule, large, coal-fired boilers must meet emissions limits for CO and mercury (Hg). Existing sources have until May 21, 2014, to comply, but new sources (built or rebuilt after June 4, 2010) were required to meet the stated emissions limits by May 20, 2011. New sources also must meet the emissions limits for particulate matter (PM).
Oil- and biomass-fired boilers built prior to June 4, 2010, do not have to meet emissions limits, but those built after that date must have met particulate matter emissions limits by May 20, 2011, or upon startup.
Facilities that are now required to meet stricter emissions limit requirements have several options to help meet the requirements or avoid applicability altogether. Among the options are burner conversions that can increase fuel efficiency and decrease emissions, fuel-train conversions that can help minimize or eliminate the use of oil, or a boiler replacement, which can maximize performance while minimizing emissions. PH
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