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Article # 0066
Environmental Regulation Considerations when Constructing a Process Heater in a Nonattainment Area
This article discusses the environmental regulations applicable to the construction of a new process heater in a Nonattainment Area. Its important to understand, that when evaluating environmental regulations, terms such as "process heater" or " Nonattainment Area" have specific meanings, or definitions, which are presented within the regulations themselves.
In general, a process heater is an enclosed device using controlled flame wherein the primary purpose is to transfer heat indirectly to a process material (liquid, gas, or solid) or to a heat transfer material (e.g., glycol or oil) for use in a process requiring heat. This is instead of generating steam to heat material, when steam is used, the heating device is known as a boiler or steam generating unit. So process heaters are devices that use fuel such as natural gas or petroleum liquids whereby the combustion gases do not come into direct contact with process materials. The heater's exhaust gases from the is the emission source of air pollutants and
Nonattainment area refers to a designated geographical area that does not meet (or that contributes to ambient air quality in a nearby area that does not meet) the national primary or secondary ambient air quality standard for the pollutant being regulated. For example, the Dallas - Fort Worth (DFW) area is currently "Nonattainment" for ground-level ozone which is a contributor and component of smog. Chemical precursors that react in the ambient air to form ozone include nitrogen oxides (or NOx) and volatile organic compounds (or VOC) both of which are products of the heater's combustion reaction. Additionally, pollutants such as sulfur dioxide (or SO2), carbon monoxide (CO), and particulate matter (or PM) are common pollutants regulated when a new heater is to be constructed. Below I evaluate the various federal and state environmental regulations or programs potentially applicable to a new process heater to be located at a fuel distribution terminal in the DFW area.
Federal Regulations: New Source Performance Standards (NSPS)
A NSPS regulation has not been promulgated for process heaters located at fuel distribution terminals. NSPS 40 CFR 60 - Subpart J does apply to process heaters located at petroleum refineries. NSPS regulations are constantly changing and should be evaluated just prior to the construction of the unit.
Federal National Emission Standards for Hazardous Air Pollutants (NESHAP)
NESHAP regulations have been proposed for major sources of Hazardous Air Pollutants (HAP) that could affect process heaters. Most fuel distribution terminals are classified as area source (also known as minor or non-major source) under NESHAP regulations and would not apply. A major source facility under this regulation emits or has the potential to emit 10 or more tons per year (tpy) of any single air toxic or 25 tpy or more of any combination of air toxics.
State Pollutant Specific Regulations - 30 TAC Chapter 117 NOx emissions
This regulation only applies to internal combustion engines in the DFW area, so it is not applicable to a new process heater since it is not an engine. In Houston-Galveston Nonattainment area it applies to gas-fired process heaters requiring a maximum 0.036 lb NOx/MMBtu heat input (or alternatively, 30 parts per million by volume (ppmv) at 3.0% oxygen (O 2 ), dry basis). It is possible that this regulation could extend its scope to the DFW area in the future.
State Equipment Permitting Regulations - 30 TAC Chapter 116 or Preconstruction Air Permitting Regulation
This regulation incorporates the requirement of selecting Best Available Control Technology (BACT) for newly installed or modified process heaters. The current BACT for process heaters is maintained at the Texas Commission on Environmental Quality (TCEQ). It indicates that process heater burners should be chosen that provide the best NOx performance (lowest concentration in heater exhaust) for the burner configuration and gaseous fuel used. A case-by-case review is necessary if NOx in the heater exhaust would exceed 0.01 lb/MM Btu fired average annually. CO concentration in heater exhaust should not exceed 50 ppmv corrected to 3 % oxygen.
This regulation also has specific requirements that must be met to obtain a preconstruction air quality permit or amendment to an existing permit to include the heater. Permit application materials that are required to be submitted for review by state permit reviewers include the following:
Detailed description of process to include any effect to existing upstream and downstream equipment due to the heater addition. For example, if the heater increased processing capacity, such that additional product is produced, how will that increased production affect existing emission sources. All minor equipment to support the new heater must be identified as well. Equipment such as new valves, connectors, pumps, and/or compressors are themselves emitters of VOC and would need to be included in the permit application.
Detailed process flow diagram clearly indicating the heaters position in the overall plant process and its interconnectiveness to feed, product and by-product streams.
Detailed emission rate calculations of all air pollutants that will be emitted by heater or affected upstream or downstream emission source. Along with the mass emission rates, all exhaust characteristics must be identified including the exhaust velocity, temperature, release height above ground, and release diameter. The emission rates and characteristics may be required in an air dispersion modeling study to evaluate off-property impacts of individual air contaminants if such a study is requested or indicated.
The application requires other detailed information identified within the states air permitting forms and guidelines and the application must be approved and the permit or permit amendment issued prior to the start of construction. In addition, the agency may require stack testing of the heater exhaust to verify that the actual emission rates measured will not exceed the maximum emission rates identified in the application.
All regulations are subject to change (and they regularly do) as new emission control technology is developed and more stringent regulations are passed. New regulations can require the owner to modify or replace the heater burners or the heater itself to meet the new standards even though there is still useful life remaining in the equipment. Since this is the case, all regulations should be used as a guideline of what is currently expected (minimum) from proven and readily available technology. So even though a specific regulation may not apply, the owner should try to select the best technology available giving consideration for cost, useful life, as well as applicable and non-applicable regulatory limits.
Jack L. Bullard, P.E. is an Engineering Partner of Bullard Environmental Consulting, Inc. He has over 20 years experience in environmental engineering, compliance, and permitting. Jack has a Bachelors of Science Degree in Chemical Engineering from the University of Texas at Austin.
Jack L. Bullard, P.E. No. 83547
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