7/95 ATTACHMENT 1 RULE 74.15.1 : 8 ATTACHMENT 1

Equipment Tuning Procedure

for Forced Draft

- fired Equipment 1

Nothing in this Equipment Tuning Procedure shall be construed to require any act or omission

that would result in unsa fe 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 Divisio n), the Federal Occupational Safety and Health Administration, or other relevant regulations and requirements.

1. Operate the unit at the firing rate most typical of normal operation. If the unit experiences significant load variations during normal oper ation, 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 2 (for liquid fuels), and observe flame conditions after 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 3 , and if the CO emissions are low and there is not smoke, the 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 pe rcent over the level measured in Step 2. As in Step 2, 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

stabi lizes.

4. Decrease combustion air flow until the stack gas oxygen concentration is at the level measured in Step 2. From this level gradually reduce the combustion air flow, in small increments. After each increment, record

1

. This tuning procedure is based on a tune

- up procedure developed by KVB, Inc. for the

EPA.

2

. The smoke

- spot number can be determined with ASTM Test Method D

- 2156 or with the

Bacharach method.

3

. Typical minimum oxygen levels for boilers at high firing rates are:

1. For natural gas: 0.5%

- 3% 2. For liquid fuels: 2%

- 4%7/95 ATTACHMENT 1 RULE 74.15.1 : 9

the stack gas temperature, o xygen 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 in reached:

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 lim itations

- such as low windbox/furnace pressure differential,

built in air

- flow limits, etc.

6. Develop an 0 2 /CO curve (for gaseous fuels) or 0 2 /smoke curve (for liquid fuels) similar to those shown in Figures 1 and 2 using the excess oxygen and CO or smo ke

- spot number data obtained at each combustion air flow setting.

7. From the curves prepared in Step 6, find the stack gas oxygen levels where the CO

emissions or smoke

- spot number equal the following values:

Fuel Measurement Value

Gaseous CO Emissio ns 400 ppm

#1 & #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 CO or smoke threshold, or as the minimum excess

o xygen 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 adjustmen ts can probably be made to improve fuel and air mixing, thereby allowing operation with less air.

8. Add 0.5 to 2.0 percent to the minimum excess oxygen level found in Step 7 and reset burner controls to operate automatically at this higher stack gas oxyg en level. This7/95 ATTACHMENT 1 RULE 74.15.1 : 10

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 unit varies significantly during n ormal operation, repeat Steps 1

- 8 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 opti mum excess oxygen level at all firing rates. If this is the case, choose the burner control settings that give best performance over the range of firing rates. If one firing rate predominates, settings should optimize conditions

at that rate.

10. Verify that the new settings can accommodate the sudden 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 Step 5 result, reset t he combustion controls to provide a slightly higher level of excess oxygen at the affect 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.7/95 ATTACHMENT 1 RULE 74.15.1 : 11 Figure 1

Oxygen/CO Characteristic Curve

Figure 2

Oxygen/Smoke Characteristic Curve7/95 ATTACHMENT 2 RULE 74.15.1 : 12 ATTACHMENT 2

Equipment Tuning Procedure

for Natural Draft

- Fired Equipment

Nothing in this Equipment Tuning Procedure shall be construe d 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 In dustrial Relations (Occupational Safety and Health Division). the Federal Occupational Safety and Health Administration, or other relevant regulations and requirements. Steps in the Procedure not applicable to specific units may be omitted.

1. Preliminar y Analysis

a. Verify that the boiler, steam generator, or process heater (unit) is operating at the lowest pressure or temperature that will satisfy load demand. This pressure or temperature will be used as a basis for comparative combustion analysis be fore

and after tune

- up.

b. Verify that the unit operates for the minimum number of hours and days necessary to perform the work required.

c. Verify that the size of air supply openings is in compliance with applicable codes and regulations. Air supply openings must be fully open when the burner is firing

and air flow must be unrestricted.

d. Verify that the vent is in good condition, properly sized and free from obstruction.

e. Perform a combustion analysis (CO, O 2 , etc.) at both high and low fire, if possible. Record all data, as well as the following:

(1) Inlet fuel pressure at burner at high and low firing rates. (2) Pressure above draft hood or barometric damper at high, medium and low firing rates. (3) Steam pressure, water temperature , or process fluid pressure or temperature entering and leaving the unit. (4) Inlet fuel use rate if meter is available.

2. Checks & Corrections

a. Clean all dirty burners or burner orifices. Verify that fuel filters and moisture traps are in place, clean, and operating properly. Confirm proper location and7/95 ATTACHMENT 2 RULE 74.15.1 : 13 orientation of burner diffuser spuds, gas canes, etc. Replace or repair damaged or missing burner parts.

b. Remove external and internal sediment and scale from heating surfaces.

c. Verify th at the necessary water or process fluid treatment is being used. Confirm flushing and/or blowdown schedule.

d. Repair all leaks. In addition to the high

- pressure lines, check the blow

- off, drain, safety valve, by pass lines and, if used, the feed pump.

3. Safety Checks

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 setting and verify that the setting is consistent with unit load requirements.

e. Check limit safety control and spill switch.

4. Adjustments

Perform the following checks and adjustments on a warm unit at high fire:

a. Adjust unit to fire at the maximum inlet fuel use rate: record fue l manifold

pressure.

b. Adjust draft and/or fuel pressure to obtain acceptable, clean combustion at both high, medium and low firing rates. The carbon monoxide (CO) value should not exceed 400 parts per million (PPM) at 3% O 2

.

Verify that unit light

- offs are smooth and safe. Perform a reduced fuel pressure test at both high and low firing rates in accordance with the manufacturers

instructions.

c. Check and adjust the modulation controller. Verify proper, efficient and clean combustion through the range of firing rates.

When optimum performance has been achieved, record all data.

5. Final Test7/95 ATTACHMENT 2 RULE 74.15.1 : 14

Perform a final combustion analysis on the warm unit at high, medium and low firing rates, if possible. Record data obtained from combustion analysis, as well as the following:

a. Inlet fuel pressure at burner at high and low firing rates.

b. Pressure above draft hood or barometric damper at high, medium and low firing

rates.

c. Steam pressure, water temperature, or process fluid pressure or tempe rature entering and leaving the unit.

d. Inlet fuel use rate if meter is available.