How To Maintain Boilers in Thermal Plants
When it comes to running a thermal plant, boilers play an essential role in carrying out day-to-day activities. Hence, if the boiler runs dry or the turbine blades get damaged due to water induction, the result can be extremely expensive. This is because repairing a boiler can be very costly and even time consuming, and the cost of plant downtime and lost production can be in millions.
Hence, it’s imperative to maintain the boilers in thermal plants efficiently to prevent dramatic damage like:
- Turbine blade and disk pitting
- Boiler drum and tube
- Condenser pitting and oxidation
- Stress corrosion of condenser and feedwater heater tubing in stagnant oxygenated water
In this article, we will cover the best ways to maintain a boiler in a thermal plant.
Best Ways To Maintain Boilers In A Thermal Plant
The procedure of maintaining boilers generally fall into two broad categories:
- The wet procedure
- The dry procedure
The Wet Procedure
With an exception for units that receive oxygenated treatment (OT), the wet procedure generally consists of filling up the majority of the system with a mix of ammonia and hydrazine, known as an alkaline reducing solution. This solution prevents air ingress with the help of pressurization using an inert gas, commonly known as nitrogen. Depending on the design, the solution could be eliminated using a viable nitrogen blanketing system. Moreover, circulation is maintained using a head tank or a positive nitrogen pressure, coupled with water at normal operating levels. The use of a nitrogen blanketing solution is generally recommended when it comes to the wet procedure, not only for boilers but also with other heat cycle components. Also, it’s essential to regularly monitor the oxygen scavenger concentration during the procedure while circulating the water routinely to prevent stagnant conditions. The wet procedure should be carried out regularly during short periods.
The Dry Procedure
When it comes to thermal plant overhauls or tube repairs, the dry procedure is generally recommended. In this procedure, the boiler is drained by removing all the water, followed by pressurization using a moisture-free inert gas. You can also make use of dehumidified air to achieve a low moisture environment. The dry procedure technique works by emptying the boiler with a preferred solution and once empty; all the vents will be rapidly opened to encourage air circulation, which will evaporate any retained water. If a boiler hasn’t been used for a while, or if it needs to be used for a prolonged period, the dry procedure is generally recommended. This is because it is by far the most convenient and flexible solution when it comes to maintaining boilers.
With depleting resources like fossil fuels, thermal plants are one of the most used plants to ensure the demand for energy is met. In such cases, a boiler breaking down could have grave consequences. Hence, it is always recommended to maintain all components in the plant, especially boilers regularly. Companies like Thermax can help execute this with flexible and affordable solutions.