Boiler maintenance should always be performed with skill and in accordance with valid rules and regulations from the authorities, and some recommendations for periodic inspections and maintenance are provided below.
Daily Operation
Every day, during normal boiler operation, some work and check procedures must be considered.
- Examine the boiler’s steam pressure and water level.
- Check that the feed water control system is working properly.
- Examine the boiler water condition and take any necessary countermeasures for feed and boiler water treatment. Blow down the boiler if necessary.
- Examine the operation of the oil burner at various capacities using the inspection holes on the boiler.
- After that, check the flue gas temperature and/or the draft loss across the boiler. The pin-tube section must be cleaned if either the temperature or the draft loss is too high.
Weekly Routine Checks
- For about 10-15 seconds, drain each water level glass.
- In the event of contaminated boiler water or insufficient water treatment, the water level glasses must be drained more frequently.
- Examine the water level safety device.
- The boiler was blown down based on the boiler water tests. Open the blow-down valves quickly for a few seconds, then close and reopen for 5-10 seconds.
- Repeat this operation as needed based on the boiler water tests.
- When necessary, use the scum valve to blow out the scum. The scum blow out process must be repeated until the drained water is clean.
Monthly Routine Checks
- All back-up pumps should be tested.
- Examine all boiler mountings for damage or leaks, and repair or replace as needed.Kangrim Repair is one example of a service that must be availed if the boiler has any damages or leaks.
- Check the high steam pressure switch’s operation by lowering the set point or increasing the steam pressure, for example, by slowly closing the main steam valve. The burner must automatically shut down.
Inspection of Furnace
At least twice a year, the furnace should be inspected. The following issues should be considered during this inspection:
- Examine the refractory lining for cracks and make sure the furnace walls are free of excessive soot deposits.
- Examine the area opposite the burner closely. Excessive soot accumulation indicates that the burner should be adjusted.
- Examine the pin-tube elements for damage and soot deposits to ensure that they are within normal limits.
Inspection of Boiler Water Side
- At least twice a year, the boiler’s water side (interior) must be thoroughly inspected. This inspection is crucial and, without a doubt, the most important of all maintenance measures because it has a direct impact on the boiler’s longevity and security.
- Hard deposits, corrosion, and circulation disturbances can be detected early in these inspections, and preventive measures must be implemented to avoid unexpected material damage and boiler breakdown.
- Hard deposits on the furnace wall and pin-tubes reduce heat transfer properties and reduce boiler capacity.
- Furthermore, it is possible to determine whether the feed water treatment was satisfactory and whether the blow-down was completed adequately.
- Incorrect feed water treatment is frequently the cause of hard deposits or corrosion.
- Inadequate blow-down will result in sludge deposits in the tubes and sludge accumulation in the boiler’s bottom.
- If hard deposits are not removed, they may cause overheating in the boiler plate material that is exposed to the flame in the furnace wall area. This may result in material damage.
- Incorrect feed water treatment does not always result in hard deposits. For example, a pH-value that is too low or too high may cause an electrolytic reaction, resulting in boiler corrosion.
- When inspecting the boiler interior, pay close attention to all parts and look for deposits, corrosion, and cracks. This inspection should be given special attention.
Procedure and Remarks for Inspection
- Turn off the boiler and allow it to cool (below 100°C). The boiler should NOT be depressurised by lifting the safety valves and then filled with cold feed water because the stress caused by too rapid cooling may cause damage.
- Close all valves and drain the boiler. If the boiler is linked to another, ensure that the valves between them are closed.
- Unscrew and remove the boiler’s manhole hatch(es) and enter the boiler when it is sufficiently cold. Inspect the welding in the boiler. A thorough examination should be performed to rule out any possibility of corrosion or crack formation.
- Special attention should be paid to the water line area of the pressure vessel, where oxygen pitting may occur.
- If deposits are discovered in the boiler tubes, the boiler should be chemically cleaned.
- It is best to hire a cleaning company that will inspect the boiler deposits and treat it accordingly.
- Following chemical treatment, the boiler should be blown down at least twice a day for about a week. This will prevent excessive sludge deposits caused by chemical treatment from accumulating in the pressure vessel’s bottom.
Contamination
If the boiler becomes contaminated with foreign substances such as oil, chemicals, corrosion products, and so on, it is critical to act quickly to avoid boiler damage.
Layers of thin oil films, mud, and other materials exposed to the heating surfaces disrupt heat transfer in the boiler, resulting in overheating and burned-out pressure parts. To remove such contamination, a boiling out or acid cleaning must be performed as soon as possible.
Corrosion products from the pipe system or inadequate boiler water treatment can cause corrosion in the boiler. As a result, it is critical to note that such events do not occur in the system.
