MOJAVE DESERT AIR QUALITY MANAGEMENT DISTRICT

RULE 1157 - BOILERS AND PROCESS HEATERS
(Adopted: 10/26/94; Amended: 05/19/97)

(A) General

  1. Purpose:

    1. The purpose of this rule is to limit NOx emissions from industrial, institutional, and commercial boilers, steam generators, and process heaters.

  2. Applicability:

    1. This rule applies to new and existing boilers, steam generators, and process heaters located within the Federal Ozone Non-attainment Area with rated heat inputs of greater than or equal to 5 million Btu per hour (MMBtu/hr) which are used in all industrial, institutional, and commercial operations, including permit units used by independent power producers and cogeneration projects.
    2. This rule does not apply to permit units whose sole purpose is the production of steam for electrical power generating equipment when the permit unit is located at a facility directly regulated by a Public Utilities Commission.

  3. Applicability of other District Rules: Compliance with this rule does not exempt a person from complying with any other applicable State, federal or local law, statute, code, ordinance, rule, or regulation.

(B) Definitions

  1. For the purposes of this rule, the following definitions shall apply:
    1. "Annual Heat Input" - the total heat input of fuels, in Btu, burned by a permit unit in a calendar year, as determined from the higher heating value and cumulative annual usage of each fuel.

    2. "Best Available Retrofit Control Technology" (BARCT) - an emission limitation that is based on the maximum degree of reduction achievable, taking into account environmental, energy, and economic impacts by each class or category of source.
    3. "Boiler or Steam Generator" - any combustion equipment (fired with any fuel) used to produce steam. Boiler or steam generator does not include any waste heat recovery boiler that is used to recover sensible heat from the exhaust of a combustion turbine.
    4. "Cogeneration Facility" - a facility which produces:
      1. electric energy; and
      2. steam or forms of useful energy (such as heat) which are used for industrial or commercial heating or cooling purposes.
    5. "Emissions Control Plan" - a document which outlines how an existing facility will comply with the requirements of this rule. The plan shall contain the following:

      1. a list of all permit units with their rated heat inputs and estimated annual heat inputs; and
      2. for permit units subject to subsection (C)(3)(a) or (C)(4)(a), for each permit unit listed, the selected method of achieving the applicable standard or standards of subsection (C)(3)(a) or (C)(4)(a); and
      3. for permit units subject to subsection (C)(3)(b) or (C)(4)(b), for each permit unit listed, a selection of one of the four options specified in subsection (C)(3)(b) or (C)(4)(b) to achieve compliance with this rule; and
      4. for permit units for which installation of NOx reduction technology by May 31, 1995 is not practicable, a demonstration of why such installation cannot be achieved by that date, as well as a schedule of clearly defined compliance milestones that represent the most expeditious schedule practicable toward final compliance.
    6. "Federal Ozone Non-attainment Area" - that portion of San Bernardino County that lies within the lines which begin at:
      1. the San Bernardino/Riverside County boundary, running north along the range line common to Range 3 East and Range 2 East
      2. then west along the township line common to Township 2 North and Township 3 North;

      3. then north along the San Bernardino/Los Angeles County boundary and the San Bernardino / Kern County Boundary;
      4. then east along latitude 35 degrees, 10 minutes north;
      5. then south along longitude 115 degrees, 45 minutes west and west along the San Bernardino / Riverside County Boundary(see Map 1).
    7. "Heat Input" - the chemical heat released due to fuel combustion in a permit unit, using the higher heating value of the fuel. This does not include the sensible heat of incoming combustion air.

    8. "High Annual Heat Input Permit Unit" - a permit unit with an annual heat input greater than or equal to 50,000 million Btu (MMBtu).

    9. "Higher Heating Value (HHV)" - the total heat liberated per mass of fuel burned (Btu per pound), when fuel and dry air at standard conditions undergo complete combustion and all resultant products are brought to standard conditions.

    10. "Independent Power Producer" - a power plant which is not directly regulated by a Public Utilities Commission, which provides power to an electric utility rather than directly to rate-payers, and which is a Qualifying Small Power Production Facility per Public Utility Regulatory Policies Act regulations (18 CFR Ch.1, Subpart B).

    11. "Low Annual Heat Input Permit Unit" - a permit unit with an annual heat input less than 50,000 million Btu (MMBtu).

    12. "NOx Emissions" (NOx) - the sum of any oxides of nitrogen which can be measured in the flue gas.

    13. "Parts per Million (by Volume)" (ppmv) - the number of gas molecules of a given species, or group, in one million total gas molecules.

    14. "Permit Unit" - any boiler, steam generator or process heater required to have a Permit to Operate pursuant to District Rule 203.

    15. "Process Heater" - any combustion equipment fired with any fuel, which transfers heat from combustion gases to water or process streams. Process heater does not include any dryers in which the material being dried is in direct contact with the products of combustion, such as: cement or lime kilns, glass melting furnaces, or smelters.

    16. "Reasonably Available Control Technology" (RACT) - the lowest emission limitation that a particular source is capable of meeting by the application of control technology that is reasonably available considering technological and economic feasibility.

    17. "Rated Heat Input" - the heat input capacity (in MMBtu/hr) specified on the nameplate of the permit unit, unless:
      1. the permit unit is limited by permit condition to a lesser heat input than specified on the nameplate, in which case the limiting condition shall be used as the rated heat input; or
      2. the permit unit is operated above the heat input capacity specified on the nameplate, in which case the maximum operated rate shall be used as the rated heat input.
    18. "Start-up Period" - the one hour time period immediately following a continuous period in which fuel flow to the permit unit is zero, or shut off for 30 minutes or longer.

    19. "Shut-down Period" - the one hour time period immediately preceding a continuous period in which fuel flow to the permit unit is zero, or shut off for 30 minutes or longer.

    20. "Solar Power Production Facility" - an independent power producer which is a Solar Thermal Powerplant per Public Resources Code §25140.


(C) Requirements

  1. RACT standard versus BARCT standard applicability: RACT standards shall apply to all permit units, unless BARCT standards are applicable to the particular existing permit unit. BARCT standards shall apply to any existing permit units currently permitted to emit more than five tons per day or more than 250 tons per year of NOx.

  2. An owner or operator of any permit unit(s) subject to subsection (C)(3)(a) or (C)(4)(a) below shall have the option of complying with either the ppmv or pounds per million Btu (lbs/MMBtu) NOx emission limits.

  3. RACT Standards:
    1. High annual heat input permit units, as defined in Section (B), shall not emit:
      1. carbon monoxide in excess of 400 ppmv; and
      2. NOx in excess of 70 ppmv, and/or 0.084 lbs/MMBtu of heat input, when operated on gaseous fuel; and
      3. NOx in excess of 115 ppmv, and/or 0.150 lbs/MMBtu of heat input, when operated on liquid and/or solid fuels; and
      4. NOx in excess of the heat-input weighted average of the limits specified in (C)(3)(a)(ii) and (C)(3)(a)(iii), above, when operated on combinations of gaseous and liquid and/or solid fuels.

        Sample calculation:



        where:
        x = annual heat input from gaseous fuel
        y = annual heat input from liquid and/or solid fuel


    2. Low annual heat input permit units, as defined in Section (B), shall:
      1. be operated in a manner that maintains stack-gas oxygen (O2) concentrations at less than or equal to 3.0 percent by volume on a dry basis; or
      2. be operated with a stack-gas oxygen trim system set at 3.00±0.15 percent oxygen by volume on a dry basis; or
      3. be tuned at least annually in accordance with the procedure described in Section (I), a modification of the tuning procedure described in Section (I) as approved by the APCO, or the permit unit manufacturer's specified tune-up procedure, by a technician that is qualified, to the satisfaction of the Air Pollution Control Officer, to perform a tune-up; or
      4. be operated in compliance with the applicable emission levels specified in subsection (C)(3)(a).
  4. BARCT Standards:
    1. High annual heat input permit units, as defined in Section (B), shall not emit:
      1. carbon monoxide in excess of 400 ppmv; and
      2. NOx in excess of 30 ppmv, and/or 0.036 lbs/MMBtu of heat input, when operated on gaseous fuel; and
      3. NOx in excess of 40 ppmv, and/or 0.052 lbs/MMBtu of heat input, when operated on liquid and/or solid fuels ; and

      4. NOx in excess of the heat-input weighted average of the limits specified in (C)(4)(a)(ii) and (C)(4)(a)(iii), above, when operated on combinations of gaseous and liquid and/or solid fuels.

        Sample calculation:



        where:
        x = annual heat input from gaseous fuel
        y = annual heat input from liquid and/or solid fuel


    2. Low annual heat input permit units, as defined in Section (B) shall:
      1. be operated in a manner that maintains stack-gas oxygen concentration at less than or equal to 3.0 percent by volume on a dry basis; or
      2. be operated with a stack-gas oxygen trim system set at 3.00±0.15 percent oxygen by volume on a dry basis; or
      3. be tuned at least annually in accordance with the procedure described in Section (I), a modification of the tuning procedure described in Section (I) as approved by the APCO, or the permit unit manufacturer's specified tune-up procedure, by a technician that is qualified, to the satisfaction of the Air Pollution Control Officer, to perform a tune-up; or
      4. be operated in compliance with the applicable emission levels specified in subsection (C)(4)(a).

  5. General Equipment Requirements:
    1. Owners or operators of permit units which simultaneously fire combinations of different fuels, and are subject to the requirements of subsection (C)(3)(a) or (C)(4)(a), shall:
      1. install mass flow rate meters in each fuel line; or
      2. install volumetric flow rate meters in conjunction with temperature and pressure probes in each fuel line; or
      3. maintain a fuel log in the form and manner prescribed and approved by the APCO.
    2. Owners or operators of permit units which employ flue-gas NOx reduction technology, and are subject to the requirements of subsection (C)(3)(a) or (C)(4)(a), shall:
      1. install meters as applicable to allow instantaneous monitoring of the operational characteristics of the NOx reduction equipment; or
      2. maintain a log of NOx reduction equipment operational characteristics in the form and manner prescribed and approved by the APCO.
    3. Owners or operators of permit units which are subject to (C)(3)(b) or (C)(4)(b) and choose to comply with (C)(3)(b)(ii) or (C)(4)(b)(ii), respectively, shall install a stack-gas oxygen trim system.

(D) Exemptions

  1. During periods of unexpected curtailment of normal gaseous fuels, permit units subject to the requirements of subsection (C)(3)(a) or (C)(4)(a) which normally burn only gaseous fuel shall comply with a NOx emission limit of either 150 ppmv or 0.215 pound per million Btu of heat input when burning liquid or solid fuel. (This exemption shall not exceed the period of natural gas curtailment, and specifically excludes equipment and emission testing time not exceeding 48 hours per calendar year).

  2. Permit units which are located at solar power production facilities and are subject to the requirements of subsection (C)(3)(a) shall comply with the following NOx emission limits:
    1. 125 ppmv, when the permit unit is located at SEGS VI or SEGS VII and is operating at 40% or less of rated heat input; and
    2. 80 ppmv, when the permit unit is located at SEGS II and is operating at 40% or less of rated heat input; and
    3. those limits specified in (C)(3)(a), for all other such permit units and operating conditions.

  3. The provisions of Section (C) of this rule shall not apply to permit units which have no annual heat input (annual heat input equals zero). The owner or operator of any permit unit who wishes to claim an exemption pursuant to this subsection shall meet the record keeping requirements of this rule so as to be able to prove the exemption status.


(E) Monitoring and Records

  1. Emissions Compliance Testing:
    1. Frequency: All permit units covered under subsections (C)(3) and (C)(4) shall demonstrate compliance through emission compliance testing not less than once every 12 months, except that permit units complying with subsection (C)(3)(b)(iii) or (C)(4)(b)(iii) shall be tuned not less than once every 12 months, and permit units claiming an exemption pursuant to subsection (D)(1) which burn a secondary fuel for less than 720 cumulative hours in the twelve month consecutive period prior to testing shall not be required to perform compliance testing for that fuel.
    2. Procedures:
      1. Compliance testing required by this rule shall follow the administrative procedures outlined in the District's Compliance Test Procedural Manual. All emission determinations shall be made as stipulated in the test protocol accepted by the District.
      2. Emission determinations shall include, at a minimum, one emission compliance test conducted at 90% of the maximum firing rate allowed by the District permit or at normal operating conditions as determined and approved by the APCO.
      3. No compliance determination shall be established based on data obtained from compliance testing, including integrated sampling methods, during a start-up period or shut-down period.
      4. All ppmv emission limits specified in subsections (C)(3)(a), (C)(4)(a) and (D)(1) are referenced at dry stack-gas conditions and 3.0 percent by volume stack-gas oxygen.
      5. All lbs/MMBtu NOx emission rates shall be calculated as pounds of nitrogen dioxide per MMBtu of heat input.
      6. All emission concentrations and emission rates shall be based on hourly averages.
  2. Records and Reporting
    1. For all permit units subject to this rule, the owners/operators shall monitor and record for each permit unit the HHV and cumulative annual usage of each fuel. The cumulative annual usage of each fuel shall be monitored from utility service meters, purchase or tank fill records, or by any other acceptable methods, as approved by the Air Pollution Control Officer. A statement of the heat input for the previous calendar year shall be submitted to the District by March 1 each year.
    2. For permit units exempt from subsection (C)(3)(a) or (C)(4)(a) in accordance with subsection (D)(1), the owner/operators shall monitor and record for each permit unit the cumulative annual hours of operation on each liquid or solid fuel.
    3. All data shall be kept current and on site for a minimum of two years, and provided to District or state personnel on request.
    4. The owners or operators of permit units subject to this rule shall submit all required compliance test reports to the District.
    5. For each permit unit complying with subsection (C)(3)(b)(iii) or (C)(4)(b)(iii), records verifying that the tune-up has been performed for each fuel burned shall be maintained on site for two years. If a different tune-up procedure from that described in Section (I) is used, then a copy of this procedure shall be kept on site for two years. Such records shall be provided on request by the APCO.
    6. Test reports shall include the operational characteristics of all flue-gas NOx reduction equipment.


(F) Test Methods

  1. Compliance with the NOx, carbon monoxide and oxygen requirements of Section C shall be determined using the following test methods:
    1. Oxides of Nitrogen - EPA Method 7E or ARB Method 100
    2. Carbon Monoxide - EPA Method 10 or ARB Method 100
    3. Stack Gas Oxygen - EPA Method 3 or 3A or ARB Method 100
    4. NOx Emission Rate (Heat Input Basis) - EPA Method 19

  2. HHV determination shall be by one of the following test methods:
    1. ASTM D 2015-85 for solid fuels; or
    2. ASTM D 240-87 or ASTM D 2382-88 for liquid hydrocarbon fuels; or
    3. ASTM D 1826-88, or ASTM D 1945-81 in conjunction with ASTM D 3588-89 for gaseous fuels.

(G) Compliance Schedule

  1. The owner or operator of permit units subject to this rule shall fulfill the following increments of progress:
    1. On or before February 28, 1995, submit an Emissions Control Plan.

    2. Install any required NOx reduction technology no later than May 31, 1995, unless such installation was demonstrated to be impracticable in the Emissions Control Plan. Those permit units for which installation by May 31, 1995 is not practicable shall fulfill, at a minimum, the following interim measures:
      1. On or before February 28, 1995, submit a complete application to the District for an Authority to Construct the NOx reduction technology; and
      2. On or before May 31, 1995, provide evidence that equipment has been ordered; and
      3. On or before January 31, 1996, take delivery of equipment; and
      4. Actual NOx reduction technology shall be installed as soon as possible but no later than March 31, 1996.
    3. Demonstrate final compliance with all applicable standards and requirements of the rule:
      1. by May 31, 1995 for permit units with NOx control technology in place or permit units subject to subsection (C)(3)(b) or (C)(4)(b); or
      2. within six months of installation of NOx reduction technology.
  2. The owner or operator of a permit unit which becomes subject to the requirements of subsection (C)(3)(a) or (C)(4)(a) by exceeding the annual heat input thresholds in subsection (B)(1)(h) for a calendar year, or by operating the permit unit so that an exemption pursuant to (D)(3) no longer applies, shall fulfill the following increments of progress:
    1. On or before December 31 of the calendar year immediately following the year that the annual heat input threshold was exceeded or the permit unit commenced operation, submit an Emissions Control Plan containing the information outlined in subsection (B)(1)(e).

    2. No later than three calendar years following the submission of the Emissions Control Plan, demonstrate final compliance with all applicable standards and requirements of the rule.
  3. Failure to perform interim measures as set forth in a submitted Emissions Control Plan shall constitute a violation of this rule.

(H) Severability of Portions of this Rule
If any portion of this rule is found to be invalid or unenforceable, such finding shall have no effect on the validity and enforceability of the remaining portions of the rule, which are severable and shall continue to be in full force and effect.

(I) Tuning Procedure

  1. Nothing in these Tuning Procedures 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.

  2. Tuning Procedure for Forced-Draft Permit units
    1. Operate the permit unit at the firing rate most typical of normal operation. If the permit unit experiences significant load variations operate it at its average firing rate.

    2. At this firing rate, record stack gas temperature, oxygen concentration, and CO concentration (for gaseous fuels) or smoke-spot number (for liquid fuels), and observe flame conditions after permit unit operation stabilizes at the firing rate selected. If the excess oxygen in the stack gas is at the lower end of the range of typical minimum values, and if the CO emissions are low and there is no smoke, the permit unit is probably operating at near optimum efficiency - at this particular firing rate. However, complete the remaining portion of this procedure to determine whether still lower oxygen levels are practical.

    3. Increase combustion air flow to the furnace until stack gas oxygen levels increase by one to two percent over the level measured in subsection (I)(2)(b). As in (I)(2)(b), record the stack gas temperature, CO concentration (for gaseous fuels), or smoke-spot number (for liquid fuels), and observe flame conditions for these higher oxygen levels after boiler operation stabilizes.

    4. Decrease combustion air flow until the stack gas oxygen concentration is at the level measured in (I)(2)(b). From this level gradually reduce the combustion air flow, in small increments. After each increment, record the stack gas temperature, oxygen concentration, CO concentration (for gaseous fuels) and smoke-spot number (for liquid fuels). Also, observe the flame and record any changes in its condition.

    5. Continue to reduce combustion air flow stepwise, until one of these limits is reached:
        Unacceptable flame conditions - such as flame impingement on furnace walls or burner parts, excessive flame carryover, or flame instability.
      1. Stack gas CO concentrations greater than 400 ppmv.
      2. Smoking at the stack.
      3. Equipment-related limitations - such as low windbox/furnace pressure differential, built in air-flow limits, etc.
    6. Develop an O2/CO curve (for gaseous fuels) or O2/smoke curve (for liquid fuels) using the excess oxygen and CO or smoke-spot number data obtained at each combustion air flow setting.

    7. From the curves prepared in (I)(2)(f), find the stack gas oxygen levels where the CO emissions or smoke-spot number equal the following values:



      The above conditions are referred to as the CO or smoke thresholds, or as the minimum excess oxygen levels.

      Compare this minimum value of excess oxygen to the expected value provided by the combustion permit unit manufacturer. If the minimum level found is substantially higher than the value provided by the combustion permit unit manufacturer, burner adjustments can probably be made to improve fuel and air mix, thereby allowing operations with less air.

    8. Add 0.5 to 2.0 percent to the minimum excess oxygen level found in (I)(2)(g) and reset burner controls to operate automatically at this higher stack gas oxygen level. This margin above the minimum oxygen level accounts for fuel variations, variations in atmospheric conditions, load changes, and nonrepeatability or play in automatic controls.

    9. If the load of the combustion permit unit varies significantly during normal operation, repeat (I)(2)(a) through

    10. for firing rates that represent the upper and lower limits of the range of the load. Because control adjustments at one firing rate may affect conditions at other firing rates, it may not be possible to establish the optimum excess oxygen level at all firing rates. If this is the case, choose the burner control settings that give the best performance over the range of firing rates. If one firing rate predominates, setting should optimize conditions at the rate.

    11. Verify that the new settings can accommodate the sudden load changes that may occur in daily operation without adverse effects. Do this by increasing and decreasing load rapidly while observing the flame and stack. If any of the conditions in (I)(2)(e) result, reset the combustion controls to provide a slightly higher level of excess oxygen at the affected firing rates. Next, verify these new settings in a similar fashion. Then make sure that the final control settings are recorded at steady-state operating conditions for future reference.

    12. When the above checks and adjustments have been made, record data and attach combustion analysis to permit unit records. Indicate the name and title of the person performing the tune-up, the date the tune-up was performed, and sign the record.
  3. Equipment Tuning Procedure for Natural Draft Fired Permit units
    1. Preliminary Analysis
      1. CHECK THE OPERATING PRESSURE OR TEMPERATURE. Operate the permit unit 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.
      2. COMBUSTION ANALYSIS. Perform an "as is" combustion analysis (CO2, O2, etc.) with a warmed up permit unit at high and low fire, if possible. In addition to data obtained from combustion analysis, also record the following:
        1. Inlet fuel pressure at burner (at high & low fire); and
        2. Draft above draft hood or barometric damper (at high, medium, and low settings); and
        3. Steam pressure, water temperature, or process fluid pressure or temperature entering and leaving the permit unit.
        4. Permit unit rate if meter is available.
    2. Adjustments: while taking combustion readings with a warmed up permit unit operated at the rated heat input, perform checks and adjustments as follows:
      1. Adjust permit unit to fire at rate; record fuel manifold pressure.
      2. Adjust draft and/or fuel pressure to obtain acceptable, clean combustion at high, medium and low firing rates. The CO value should always be below 400 ppmv at 3% O2. If CO is high make necessary adjustments.
      3. Check to ensure permit unit light offs are smooth and safe. A reduced fuel pressure test at both high and low fire should be conducted in accordance with the manufacturer's instructions and maintenance manuals.
      4. Check and adjust operations of modulation controller. Ensure proper, efficient and clean combustion through the range of firing rates.

        When above adjustments and corrections have been made, record all data.

    3. Final Test: Perform a final combustion analysis with a warmed up permit unit at high, medium and low firing rates, whenever possible. In addition to data from combustion analysis, also check and record:
      1. fuel pressure at burner (at high, medium and low settings); and
      2. draft above draft hood or barometric damper (at high, medium, and low settings); and
      3. steam pressure, water temperature, or process fluid pressure or temperature entering and leaving the permit unit; and
      4. permit unit rate if meter is available.
      When the above checks and adjustments have been made, record data and attach combustion analysis to permit unit records. Indicate the name and title of the person performing the tune-up, the date the tune-up was performed, and sign the record.



[SIP information: Approved 04/10/00, 65 FR 18901, 40 CFR 52.220(c)(268)(8)(B)(1); Approved 11/1/96, 61 FR 56470, 40 CFR 52.220(c)(207)(I)(D)(3)]