This procedure is general in nature and as such should be adapted to the specific conditions and procedures existing at the site at the time the operation is performed.

Safety

Chemicals that are dangerous are being handled during the boilout procedure.  Read and understand all MSDS's for the chemicals being handled.  Ensure the proper personal safety equipment is available and used.   As a minimum safety glasses, chemical goggles, face shield, protective clothing and gloves should be worn when handling chemicals.

Equipment and Supplies

The following equipment and chemicals are required:

• Trisodium Phosphate (Na₃PO₄ 12H₂O)    5.5 kg/m³
              or
• Soda Ash (Na₂CO₃)                        10 kg/m³
           plus
• 46% Caustic Soda (NaOH)                      2.5 kg/m³
           plus
• Detergent                                               0.5-1.0 l/m³

• Mixing tank and agitator
• Chemical dosing pump

Procedure

1.             Remove as much oil and grease as possible from the steam drum and headers.

2.             Isolate all boiler instruments that are not required during the boilout.

3.             Ensure that all safety systems and interlocks are in operation and functioning properly.

4.             Check that all blowdown and drain valves are operational.

5.             Check that the drum gauge glasses are in good working order.

6.             Fill the boiler with clean water to a level just below the steam drum manhole.

7.             Prepare the boilout chemicals using hot water in a separate mixing tank.  Transfer the solution to the boiler through the steam drum manhole or other suitable connection.  Feed additional water into the boiler to circulate and mix the chemicals.  Fill the boiler to the level required for normal operation.

8.             Prepare the furnace and boiler for normal firing.  Fire the burner at minimum rate.

9.             As the system heats up and pressure begins to build in the boiler the following checks should be performed:.

• Check all equipment and piping to ensure they are free to expand
• Check for leaks and tighten as necessary
• Check the operation of instrumentation
• Check that the normal operating level in the steam drum is being maintained

10.          Fire the boiler to bring the pressure up to 2000 kPag (290 psig) or one-fifth (1/5) of the design pressure (whichever is lower) within 8 hours.

11.          Hold the pressure for 4 hours.  Ensure that water is circulating in the boiler  by checking the temperature of the lower drum of header.

12.          After 4 hours, shutdown the firing equipment and allow the pressure to decrease.  After the pressure has decreased, blowdown the boiler using all blowdown valves until the level is no longer visible in the sightglass.  Refill the boiler to the normal operating level after blowing down.

13.          Relight the burner and raise the pressure to 2000 kPag (290 psig) or one-fifth (1/5) of the design pressure (whichever is lower) and hold this pressure for 4 hours.  Blowdown the boiler as in step 7 and refill the boiler.

14.          Repeat the procedure of raising pressure and blowing down two (2) more times.

15.          After four complete cycles of blowing down the boiler contents, shut off the burner and allow the boiler to cool.

16.          When the drum pressure drops to 150 kPag (22 psig), open the drum vent wide open to depressurize the boiler.  When the temperature of the steam drum falls below 90^oC, drain the boiler.

17.          After the boiler is completely drained, fill the boiler with clean rinse water to the top of the gauge glass.  Allow the boiler to cool until it is cold enough to enter for inspection.  Drain the water.

18.          Inspect the boiler and steam drum internals to ensure all oil and grease are removed.  Check the boiler internals to ensure that have not been disturbed during the boilout operation.

19.          If the internal inspection indicates unsatisfactory cleaning the entire boilout procedure must be repeated.

20.          Once the boilout is completed satisfactorily, the boiler can be placed into normal operation.