Power plant wetted parts (boiler inner tube walls, condensers, etc) become susceptible to corrosion as air (oxygen) is introduced with the draining process during layups or outages.  Remaining residual moisture along with the oxygen introduced, sets up oxidation or galvanic corrosion during the layup or outage period, hence reducing the life of  parts such as boiler tubes and condensers within industrial boilers, HRSG combined cycle power plants, and large gas, oil, and coal fired power plants.  Oxidation can occur at an alarming rate.  Corrosion is detrimental to the quality and integrity of the power plant, requiring great expense and time to correct or replace.

The ideal situation is to prevent corrosion before it can begin.  In order to prevent corrosion in power plant process equipment, it is necessary to eliminate either moisture or oxygen within the parts.  One solution to achieve this is to purge the system using clean, dry, inert nitrogen gas.  Nitrogen works to displace the presence of oxygen within the wetted parts.  Using a low pressure, slow flow nitrogen purge to eliminate oxygen inhibits the process of oxidation and corrosion.
Some power plants have used chemical inhibitors injected into the water stream as a solution to fighting the onset of corrosion.  Unfortunately, the disposal of these chemicals presents a negative and harmful effect on our environment.  In addition, if the water is drained from the wetted parts of the equipment, it is inevitable that residual water will remain which will, when combined with oxygen from the air introduced during the draining process, trigger oxidation and corrosion.

Nitrogen purging as an alternative to chemical inhibitors for power plants has many benefits, including the fact that it is an environmentally friendly solution.  Nitrogen makes up 79% of the air we breathe and can be produced at high purity simply from the air around us.  The best method for producing high purity nitrogen gas is by using a nitrogen generator.  Nitrogen generators employ a simple pressure swing adsorption or membrane technology to isolate nitrogen from the air.  Nitrogen gas can be produced on-site and on-demand with a generator, therefore saving storage and transportation costs of high pressure nitrogen gas cylinders.  

A nitrogen generator is also a more safe and reliable option over high pressure cylinders.  A nitrogen generator is easy to operate and maintain, and can be fitted with appropriate alert systems should it detect a leak.  And whereas a gas cylinder may run out of nitrogen, malfunction or be without a backup cylinder, a nitrogen generator will never run out of nitrogen because it continuously or on-demand produces N2 gas directly from the air.

Nitrogen purging at power plants is an efficient, effective method for preventing oxidation and corrosion.  Use of a nitrogen generator to produce the necessary levels of nitrogen gas is a cost effective, energy saving, environmentally friendly way to supply this resource.  Any size power plant, from a small industrial boiler, to an HRSG combined cycle power plant, to a large gas, oil, or coal fired power plant, can benefit from nitrogen purging with a nitrogen generator.  Necessary flow rates can be measured and the ideal size generator can be fitted and installed for any power plant.