SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT
RULE 1146.1 - EMISSIONS OF OXIDES OF NITROGEN FROM SMALL INDUSTRIAL, INSTITUTIONAL, AND COMMERCIAL BOILERS, STEAM GENERATORS, AND PROCESS HEATERS
(Adopted October 5, 1990)(Amended July 10, 1992)(Amended May 13, 1994)
This rule applies to boilers, steam generators, and process heaters that are greater than 2 million Btu per hour and less than 5 million Btu per hour rated heat input capacity used in any industrial, institutional, or commercial operation.
(A) be operated in a manner that maintains stack-gas oxygen concentrations at less than or equal to 3 percent on a dry basis for any 15-consecutive-minute averaging period; or
(B) be tuned at least twice per year, (at intervals from 4 to 8 months apart) in accordance with the procedure described in Attachment 1 or the unit manufacturer's specified tuneup procedure. If a different tuneup procedure from that described in attachment 1 is used then a copy of this procedure shall be kept on site. If the unit does not operate throughout a continuous six-month period within a calendar year, only one tuneup is required for that calendar year. The owner or operator of any unit(s) who chooses to comply with subparagraph (c)(2)(B) shall maintain a record for a period of two years verifying that the tuneup has been performed. No tune-up is required during a calendar year for any unit that is not operated during that calendar year; this unit may be test fired to verify availability of the unit for its intended use but once test firing is completed it shall be shutdown. Records of test firings shall be maintained for a period of two years, and shall be made accessible upon request from an authorized District representative; or
(C) meet the emission limits specified in paragraph (c)(1).
(A) A list of permits of all units with the rated heat input capacity, anticipated annual heat input; and
(B) For each unit listed, a selection of one of the three options specified in paragraph (c)(2) to achieve compliance with this rule; and
(C) Non-resettable, totalizing fuel meter(s) specifications; date of installation; and recorded fuel usage since installation.
(d) Compliance Determination
(e) Compliance Schedule
The owner or operator of units subject to this rule shall meet the following increments of progress:
(A) By January 1, 1993, submit required applications for permits to construct and operate, and
(B) By July 1, 1994, demonstrate compliance with paragraph (c)(1).
(A) By January 1, 1993, submit a plan pursuant to paragraph (c)(3), and
(B) By December 31, 1993, demonstrate compliance with paragraph (c)(2).
The provisions of paragraph (c)(1) shall not apply provided the owner or operator:
(g) Loss of Exemption
If any unit subject to a compliance plan submitted pursuant to paragraph (c)(3) exceeds 18,000 therms of annual heat input in any calendar year after 1992, the owners or operators shall:
A. Equipment Tuning Procedure1 for Forced-Draft Boilers, Steam Generators, and Process Heaters
Nothing in this Equipment Tuning Procedure shall be construed to require any act or omission that would result in unsafe conditions or would be in violation of any regulation or requirement established by Factory Mutual, Industrial Risk Insurers, National Fire Prevention Association, the California Department of Industrial Relations (Occupational Safety and Health Division), the Federal Occupational Safety and Health Administration, or other relevant regulations and requirements.
1This tuning procedure is based on a tune-up procedure developed by KVB, Inc. for the United States EPA.
2The smoke-spot number can be determined with ASTM Test Method D-2156 or with the Bacharach method. ASTM Test Method D-2156 is included in a tuneup kit that can be purchased from the Bacharach Company.
3Typical minimum oxygen levels for boilers at high firing rates are:
1. For natural gas: 0.5% - 3%
2. For liquid fuels: 2% - 4%
However, complete the remaining portion of this procedure to determine whether still lower oxygen levels are practical.
a. Unacceptable flame conditions - such as flame impingement on furnace walls or burner parts, excessive flame carryover, or flame instability.
b. Stack gas CO concentrations greater than 400 ppm.
c. Smoking at the stack.
d. Equipment-related limitations - such as low windbox/furnace pressure differential, built in air-flow limits, etc.
|Gaseous||CO Emissions||400 ppm|
|#1 and #2 oils||smoke-spot number||number 1|
|#4 oil||smoke-spot number||number 2|
|#5 oil||smoke-spot number||number 3|
|Other oils||smoke-spot number||number 4|
The above conditions are referred to as the CO or smoke thresholds, or as the minimum excess oxygen level.
Compare this minimum value of excess oxygen to the expected value provided by the combustion unit manufacturer. If the minimum level found is substantially higher than the value provided by the combustion unit manufacturer, burner adjustments can probably be made to improve fuel and air mixing, thereby allowing operation with less air.
B. Equipment Tuning Procedure for Natural Draft-Fired Boilers, Steam Generators, and Process Heaters.
Nothing in this Equipment Tuning Procedure shall be construed to require any act or omission that would result in unsafe conditions or would be in violation of any regulation or requirement established by Factory Mutual, Industrial Risk Insurers, National Fire Prevention Association, the California Department of Industrial Relations (Occupational Safety and Health Division), the Federal Occupational Safety and Health Administration, or other relevant codes, regulations, and equipment manufacturers specifications and operating manuals.
Should a different tuning procedure be used, a copy of this procedure should be kept with the unit records for two years and made available to the District personnel on request.
a. CHECK THE OPERATING PRESSURE OR TEMPERATURE.
Operate the boiler, steam generator, or heater at the lowest acceptable pressure or temperature that will satisfy the load demand. This will minimize heat and radiation losses. Determine the pressure or temperature that will be used as a basis for comparative combustion analysis before and after tuneup.
b. CHECK OPERATING HOURS.
Plan the workload so that the boiler, steam generator, or process heater operates only the minimum hours and days necessary to perform the work required. Fewer operating hours will reduce fuel use and emissions. For units requiring a tuneup to comply with the rule, a totalizing non-resettable fuel meter will be required for each fuel used and for each boiler, steam generator, and heater to prove fuel consumption is less than the heat input limit in therms per year specified in the rule.
c. CHECK AIR SUPPLY.
Sufficient fresh air supply is essential to ensure optimum combustion and the area of air supply openings must be in compliance with applicable codes and regulations. Air openings must be kept wide open when the burner is firing and clear from restriction to flow.
d. CHECK VENT.
Proper venting is essential to assure efficient combustion. Insufficient draft or overdraft promotes hazards and inefficient burning. Check to be sure that vent is in good condition, sized properly and with no obstructions.
e. COMBUSTION ANALYSIS.
Perform an "as is" combustion analysis (CO, O2, etc.) with a warmed up unit at high and low fire, if possible. In addition to data obtained from combustion analysis, also record the following:
i. Inlet fuel pressure at burner (at high & low fire)
ii. Draft above draft hood or barometric damper
1) Draft hood: high, medium, and low
2) Barometric Damper: high, medium, and low
iii. Steam pressure, water temperature, or process fluid pressure or temperature entering and leaving the boiler, steam generator, or process heater.
iv. Unit rate if meter is available.
With above conditions recorded, make the following checks and corrective actions as necessary:
a. CHECK BURNER CONDITION.
Dirty burners or burner orifices will cause boiler, steam generator, or process heater output rate and thermal efficiency to decrease. Clean burners and burner orifices thoroughly. Also, ensure that fuel filters and moisture traps are in place, clean, and operating properly, to prevent plugging of gas orifices. Confirm proper location and orientation of burner diffuser spuds, gas canes, etc. Look for any burned-off or missing burner parts, and replace as needed.
b. CHECK FOR CLEAN BOILER, STEAM GENERATOR, OR PROCESS HEATER TUBES & HEAT TRANSFER SURFACES.
External and internal build-up of sediment and scale on the heating surfaces creates an insulating effect that quickly reduces unit efficiency. Excessive fuel cost will result if the unit is not kept clean. Clean tube surfaces, remove scale and soot, assure proper process fluid flow and flue gas flow.
c. CHECK WATER TREATMENT & BLOWDOWN PROGRAM.
Soft water and the proper water or process fluid treatment must be uniformly used to minimize scale and corrosion. Timely flushing and periodic blowdown must be employed to eliminate sediment and scale build-up on a boiler, steam generator or process heater.
d. CHECK FOR STEAM, HOT WATER OR PROCESS FLUID LEAKS
Repair all leaks immediately since even small high-pressure leaks quickly lead to considerable fuel, water and steam losses. Be sure there are no leaks through the blow-off, drains, safety valve, by-pass lines or at the feed pump, if used.
a. Test primary and secondary low water level controls.
b. Check operating and limit pressure and temperature controls.
c. Check pilot safety shut off operation.
d. Check safety valve pressure and capacity to meet boiler, steam generator or process heater requirements.
e. Check limit safety control and spill switch.
While taking combustion readings with a warmed up boiler, steam generator, or process heater at high fire perform checks and adjustments as follows:
a. Adjust unit to fire at rate; record fuel manifold pressure.
b. Adjust draft and/or fuel pressure to obtain acceptable, clean combustion at both high, medium and low fire. Carbon Monoxide (CO) value should always be below 400 parts per million (PPM) at 3% 02. If CO is high make necessary adjustments.
Check to ensure boiler, steam generator, or process heater light offs are smooth and safe. A reduced fuel pressure test at both high and low fire should be conducted in accordance with the manufacturers instructions and maintenance manuals.
c. Check and adjust operation of modulation controller. Ensure proper, efficient and clean combustion through range of firing rates.
When above adjustments and corrections have been made, record all data.
Perform a final combustion analysis with a warmed up boiler, steam generator, or process heater at high, medium and low fire, whenever possible. In addition to data from combustion analysis, also check and record:
a. Fuel pressure at burner (High, Medium, and Low).
b. Draft above draft hood or barometric damper (High, Medium and Low).
c. Steam pressure or water temperature entering and leaving boiler, steam generator, or process heater.
d. Unit rate if meter is available.
When the above checks and adjustments have been made, record data and attach combustion analysis data to boiler, steam generator, or process heater records indicating name and signature of person, title, company name, company address and date the tuneup was performed.