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Nationwide Boiler news and events, industry updates, technical resources and more. You hear it first on The Nationwide Boiler Blog!

When offline, boilers can still be at risk of accumulating corrosion and deterioration that decreases the useful life of a boiler and increases maintenance and repair costs. With proper planning and preparation, a boiler can be taken offline safely with a procedure known as boiler lay up. There are two specific ways to properly shut down your boiler: dry lay up or wet lay up.

Dry lay up is a procedure that involves removing all water and moisture from the boiler. The main advantage of a dry lay up is that you can basically “set it and forget it”. There are no chemical, equipment, or fuel costs. Once completed, the boiler will just need to be checked occasionally to ensure moisture is not getting back into the boiler. A dry lay up is best for extended periods of shutdown. If the system will need to be put back online on short notice or remain in standby, this procedure would not be suitable.

A typical dry lay up procedure involves the following steps:

  1.  Perform a lock-out and tag-out and isolate the boiler from the steam system.
  2.  Perform column and bottom blowdowns and drain the boiler completely. 
  3.  Open the fireside and remove any soot from the tubes. Look for rust or scale on the pressure boundary wall, and further evaluate any   leakage. Inspect refractory and insulation.
  4.  Open the waterside and look for signs of gasket leakage and corrosion of the gasket seating surface. Inspect the entire waterside   and evaluate any scale and corrosion.
      - Any scale left on the waterside can trap moisture and oxygen and corrode the boiler further, so remove as much scale as possible.
  5.  Dry all surfaces with a fan or electric air heater.
  6.  Have a certified boiler inspector perform a thorough examination of all surfaces, internal and external.
  7.  Determine if any repairs are required - this may be the ideal time to perform repairs without any incurring downtime, since you are   already preparing for an extended offline period.
  8.  Coat the fireside with mineral oil, let it dry and close all openings including the stack. A moisture-absorbing material like silica gel or lime. 

A wet lay up is performed when the boiler is idle in standby; it is still full of water but isolated from the steam system while the burner remains offline. The procedure involves chemically treating the water to protect the metal surfaces of the boiler and is  the ideal lay up method when a boiler might need to be fired on short notice. It does, however, require additional monitoring and treatment costs that aren’t required for a dry lay up.

A typical wet lay up procedure is very similar to a dry lay up, however, the fireside should not be swabbed with mineral oil.

  1.  Follow steps 1-7 above.
  2.  Fill the boiler with the chemically treated hot water (greater than 180F) to its normal operating level. Allow air to continue to vent until  the boiler is full or until the steam boiler is at its normal operating level and warm.
  3. Once complete, boiler water should be circulated periodically to prevent stratification of chemicals. Chemical concentrations should also be monitored routinely.

Before starting a steam boiler in wet lay-up, blow down the boiler to reduce alkalinity, ensure that all tags and locks are removed, and be sure to witness a minimum of three steam cycles before allowing the boiler to run in automatic. This will help ensure proper operation after bringing a system back online from a wet lay up.

If your facility falls under a temporary business closure mandate due to the current state of the COVID-19 pandemic, it is imperative that you follow one of the procedures outlined above to properly shut down your boiler system. View this technical article provided by the National Board for more detailed information on these two types of boiler lay up procedures.

March2020Steamlines
Our quarterly newsletter, The Nationwide Boiler Steamlines, is hot off the press! Our first edition of the year is available now with a brand new look.
 
Read the newsletter to learn about what's currently happening at Nationwide Boiler, including a successful CataStak SCR system project, our response to the COVID-19 pandemic,  a new electric boiler for our rental fleet, a reminder on the importance of deaerators, and more. See our upcoming events and inventory spotlight, too.

We also officially announced the postponement of our Annual Charity Golf Tournament to 2021 to ensure the health and safety of all involved during this uncertain time. The tournament will be held at Pebble Beach on May 5-6, 2021 and we will resume with the celebration of our 40th Anniversary with the "Back to the 80's Theme". 

If you would like to be added to The Steamlines mailing distribution list,
email us at info@nationwideboiler.com.

Deaeration of boiler feed water is primarily known to remove dissolved oxygen from the water, however, there are four additional advantages of utilizing a deaerator: (1) carbon dioxide removal, (2) improved operation, (3) improved heat transfer, and (4) energy savings. In this month’s edition of Boiler Basics 101, we review the importance of including deaerators as part of your boiler plant.

Corrosion in boilers from dissolved gases leads to reduced heat transfer and efficiency losses. Both oxygen and carbon dioxide, if not removed from the water entering a boiler, will cause corrosion. Dissolved oxygen will attach to the metallic components of a steam system and form oxides, or rust, on boiler heat transfer surfaces. If carbon dioxide is present with the oxygen, the two gases together can be up to 40 percent more corrosive than if they were acting individually. Removing non-condensable gases and limiting or avoiding corrosion will greatly improve heat transfer.

Deaerators also serve the purpose of pre-heating the water before it enters the boiler. This process saves energy by recovering flash and exhaust steam from plant returns, energy that would normally be lost to the atmosphere, and utilizing it to pre-heat the feedwater. This recovered steam can account for 20 percent of the fuel typically required to provide heat for that process. Pre-heating the feedwater will also greatly reduce the chance of thermal shock caused by the expansion and contraction of heating surfaces and will ultimately improve the operation of your boiler.

Deaerators and atmospheric feedwater systems both have the same purpose and are made up of several individual devices including feed pumps, a corrosion resistant receiver tank, and a control panel. A deaerator does its job by mixing steam with soft water inside a pressurized tank, removing oxygen molecules which are then vented into the atmosphere. Atmospheric feedwater systems are non-pressurized and perform the same function while operating at a lower (atmospheric) pressure. A notable disadvantage of operating at a lower pressure is that a lesser amount of dissolved gases are removed. Although atmospheric systems are more cost effective, process requirements will dictate which system is ideal for your application.

Overall, if boiler feed water is not properly deaerated, corrosion will occur, and a boiler will operate less efficiently with a higher possibility of facing costly downtime and boiler repairs. Nationwide Boiler provides new deaerators and maintains a rental fleet of deaerating boiler feedwater systems for both low and high pressure applications. Our systems range in size for boilers 24,000 to 225,000 lb/hr, and are configured one of two ways: a skid-mounted deaerator with feed pump stand or complete mobile feedwater system including the deaerator, feed water pumps, water softener, and chemical feed system, all pre-piped and wired and installed inside of a trailer-mounted van.  

Be sure to check out our previous Boiler Basics 101 blogs and stay tuned for the next edition!

Nationwide Boiler is actively monitoring the COVID-19 pandemic and has enacted a semi-remote protocol to help “flatten the curve”. Please understand that we are still fully operational and able to support the many essential industries that we serve, including our hospitals and medical care facilities / suppliers, food processors, petroleum refineries, pulp and paper plants, manufacturing, and electrical power generation facilities. Rest assured that if an emergency need arises and a rental boiler is required quickly, we will be able to fulfill any request as we would on a typical operating basis.

Our sales, engineering and marketing teams are working remote and are fully accessible via email and phone calls. Our accounting team is working diligently to continue the functions necessary for day-to-day operations, and we have a partial shipping and receiving protocol in place with employees available on stand-by if a piece of equipment needs to get serviced and ready to ship out. At our offices, we have implemented additional measures as recommended by the CDC and the federal government, including a higher focus on cleaning and sanitizing commonly touched surfaces and the practice of social distancing. Lastly, we are restricting all non-essential travel and will carefully review and approve any essential travel to continue providing service and support.

We at Nationwide Boiler realize that this global situation affects many business and individuals, and we are here to provide as much support as possible while practicing the necessary measures to slow the outbreak. Our customers depend on us, and we will not let you down even in these uncertain times. We will continue to monitor the situation and provide updates via our social media channels as they arise.

Please feel free to reach out to us with any questions or concerns: info@nationwideboiler.com.