Boiler Blog | Nationwide Boiler Inc.

At the end of a rental boiler project, proper decommissioning is key to ensure safe transport back to the rental boiler supplier and to avoid any unforeseen costs. It’s not just about disconnecting and moving the equipment - taking a few simple precautions can prevent potential damage and ensure everything is ready for return. Review and follow the steps below for a smooth, hassle-free pick-up and return of your rental boiler equipment.

Drain & Flush

Start by thoroughly draining and flushing all the boiler lines with clean water, making sure all water drain valves are fully opened. This step helps eliminate any remaining water that could cause corrosion or freeze damage, potentially harming the system during transport or storage. Flushing the lines also removes debris and buildup, improving the boiler’s performance for future use.

Inspect

Next, take the time to carefully inspect both the fireside and waterside surfaces for any visible damage, scale buildup, or issues with the refractory lining. These areas are crucial to the boiler’s efficiency, and any damage or buildup could lead to serious problems later. It’s also a good idea to take clear photos of the boiler’s condition at the end of the rental period. This way, there is a record to reference in case there are any questions or concerns about its condition when returned.

Equipment Prep for Removal

The stack and other components that were installed upon arrival to the jobsite should be removed and mounted back on the rental boiler trailer and/or shipping skid. Be sure to securely bolt the stub stack, non-return valve, safety valves, and vent valve back into place, just as they were when the equipment was delivered. Aligning everything properly ensures that each component stays in place during transport, avoiding movement or potential damage.

Additional equipment prep should be completed as follows:

1. Cover all boiler openings: this includes the stack, steam, gas, and water connections, electrical panel, and safety valve openings.

2. Reattach running gear and gooseneck: If the trailer was taken apart for transport, ensure that the running gear and gooseneck are properly reattached before moving the trailer.

3. Check tire pressure: Before transport, it's important to check the tire pressure of the trailer. Make sure the tires are inflated to the manufacturer’s recommended levels for optimal performance and safety.

By following these steps the return process becomes seamless, protecting the rental boiler, feed system or auxiliary equipment and ensuring that everything is handled properly from start to finish. If you have questions about preparing for the return delivery of your rental boiler equipment, don't hesitate to call Nationwide Boiler at 800-227-1966.

Boilers are important components in many industrial settings and ensuring their longevity and efficiency requires proper maintenance, even during out-of-service periods. To prevent corrosion and other forms of damage when a boiler is offline, it is important to protect both the fireside and waterside of the boiler. There are two methods in achieving this – the dry method and the wet method.

Dry Storage

When a boiler is expected to be out of operation for an extended period of time and needs to be ready for service quickly, dry storage is advised. The dry storage method for industrial boilers involves draining, thoroughly cleaning, drying, and sealing the boiler to prevent moisture and air entry during extended periods of inactivity.

NOTE: If you are placing your boiler in storage for less than one month, follow steps 1 and 2 only. Be sure to follow your company guidelines and, at a minimum, label it as an oxygen-free atmosphere.

The following general procedure is advised for placing a unit into dry storage:

1. Shut down and secure the boiler. Once the pressure decreases to 20 psig, drain the boiler and header valves under air. Once the pressure is reduced to 0, open the drums to allow air to circulate and facilitate the drying of all internal surfaces.

2. If the unit is cold and filled with water, drain it under air, blow out non-drainable tubes with compressed air, and use external heat sources to aid in drying internal surfaces. Install non-porous trays with moisture absorbent (preferably silica gel) into the drums, ensuring they don't touch the drum's metal surface. Use at least one pound of absorbent per 1,000 pounds per hour of steam capacity.

3. Attach nitrogen to the steam drum vent, close all other vents, and pressurize the boiler to reach 10-15 psig with nitrogen, adjusting the amount based on the unit's volume.

4. With the boiler and superheater pressurized, alternately open all drains to purge air until the pressure drops to zero, repeating as needed to minimize oxygen levels.

5. The unit should now be stored with a nitrogen pressure of 5-10 psig in the steam drum. To maintain this pressure, ensure all connections and valves are sealed or tightly closed, and check the gas pressure daily for proper protection.

6. Boiler inspections are recommended every 3 months to ensure no corrosion is occurring and to replenish the absorbent as needed. During these inspections, air will enter the unit so you will need to repeat steps 3 and 4 to expel the air.

Wet Method

Wet storage prevents corrosion by keeping the boiler fully submerged with the right chemicals. Volatile chemicals are recommended to avoid increasing dissolved solids in the water.

The following general procedure is advised for placing a unit into wet storage:

1. Fill the boiler with deaerated, demineralized water treated with 200 ppm hydrazine and enough ammonia to reach a pH of 10.

2. Pre-mixing chemicals with water is recommended, using the blend-fill method to ensure uniform distribution in the boiler. Simply adding chemicals through the drum manhead may not adequately disperse them unless the boiler is heated to induce circulation.

3. Fill the unit with treated, demineralized water up to the normal centerline of the steam drum, then stop the filling process.

4. Refill the superheater with treated demineralized water until the steam drum level rises. Keep filling until water starts to flow from the steam drum vents. Once the filling is complete, make sure all connections are securely sealed.

5. Attach a low-pressure nitrogen source to the steam drum to maintain 5 to 10 psig and prevent air from entering the unit during storage.

6. When the boiler is ready for use, drain the superheater and the boiler drum to the normal start-up water level and resume operation.

7. Analyze the treated demineralized water weekly and add chemicals as needed through the chemical feed line to maintain recommended levels. Water samples can be collected from the continuous blowdown line or a suitable drain.

8. A boiler should not be stored wet if there is any risk of temperatures dropping to freezing, unless adequate heating is provided. Adequate heating will prevent water from freezing and avoid damage to the pressure parts.

Protection of External Surfaces:

Protection of external surfaces is also necessary during periods of extended downtime. Fireside corrosion in idle boilers can cause damage to components due to sulfuric acid from flue dust and ash. To mitigate this, remove deposits using air blasting, washing, scraping, or brushing, and neutralize any residual acid with alkaline water until the water is fully neutralized. Once flushing is complete, fill the boiler with treated water and fire it with low sulfur fuel to ensure complete drying.

Auxiliary heaters and blowers may be needed during storage to keep the metal temperature above the dew point and prevent freezing, especially with wet storage in cold conditions. Additionally, protect machined surfaces with preservative coatings and ensure there are no fuel leaks by disconnecting all oil and gas connections.

The choice between dry and wet storage depends on different factors. Although wet storage is often preferred, factors such as water quality, weather conditions, storage duration, and heat availability may make dry storage a more practical option. Be sensible when considering the conditions and needs of your boiler and choose the best storage method to ensure your equipment remains in excellent condition and is ready for use when needed.

Learning and performing proper water treatment will protect your boiler system from tube damage and corrosion, and can also contribute to maximizing boiler efficiency. In this edition of Boiler Basics 101, we will discuss the consequences of improper water treatment and how to implement a proper water treatment plan.

If feedwater is not treated properly before entering the boiler, a chemical imbalance can initiate the formation of scale. Scale is the accumulation of mineral deposits, primarily calcium and magnesium, on the internal surfaces of the boiler.  These minerals have the potential to precipitate from the water and bond to surfaces, creating a layer that may result in harm to boiler tubes, reduced boiler efficiency, and potential for ruptures. Proper water treatment methods, such as the use of water softeners and deaerators, reverse osmosis, and chemical additives to condition the water, must be employed to prevent scale formation.

1. A water softener will remove the calcium and magnesium content in the boiler’s water supply. This effectively “softens” the water before it enters a boiler and removes the minerals that are often the cause of scale in a boiler.
2. A deaerator should be utilized to mechanically remove oxygen from the water before it enters the boiler. This will prevent boiler tube failure.
3. Reverse osmosis can also be used to aid your boiler. Reverse osmosis is a process that can be used in boiler water treatment to purify and condition the water by using pressure to filter out any hardness and impurities.
4. Chemical treatment is also necessary to ensure proper water conditioning alongside the mechanical treatments listed above. Typically, the chemicals used for treatment purposes are an oxygen scavenger, scale inhibitor, and an amine to treat the steam system piping.

It is important to note that from a rental perspective, it is the customer’s responsibility to maintain the water treatment conditions of their rental boiler to avoid equipment damage and additional repair charges that can result from improper water treatment procedures. It is recommended that the services of a reputable boiler chemical consultant are retained in order to supervise the water treatment conditions on a regular basis. Weekly tasks should include maintaining daily boiler logs, conducting chemical treatment tests, providing a report from the chemical treatment consultant, and sharing maintenance records with your rental boiler supplier.

All boilers are subject to damage if proper water treatment procedures are not followed. This is an important consideration both during operation and when the boiler is idle. Maintaining a water treatment plan will not just extend your boiler’s lifespan and the durability of its components, but it will also facilitate long-term cost savings. It is an investment that pays off in the form of lower energy costs, fewer repairs, reduction of costly down time, and compliance with regulations; all contributing to long-term cost savings.

Make sure to explore our earlier Boiler Basics 101 articles and keep an eye out for the upcoming edition!

The boiler rental business began over fifty years ago, solving multiple industries’ need for temporary and emergency steam. Nationwide Boiler was at the forefront of the boiler rental industry, starting off with one of the first mobile rental boilers; a 20,000 lb/hr, 300 psig design, O-type package watertube boiler. This boiler was designed for permanent use on a highway-legal open deck trailer, making it a true mobile boiler. This new idea allowed companies to cut capital costs, save time, and be more efficient in their operations. Now, rental boilers are available for small-scale projects to industrial sized applications.

In last month’s edition of Boiler Basics 101, we discussed why rental boilers are a great choice for boiler owners in a variety of industries. To continue the topic, we will now discuss the different types of rental boilers currently on the market.

Trailer-Mounted Boilers

• Permanently installed on highway-legal trailers for easy transport by truck
• Boilers of various sizes up to 125,000 lb/hr, both saturated and superheated steam
• Detachable goosenecks and booster extensions allow for easy removal when space is limited
• Not protected from the weather and precautions must be taken for freeze protection (heat tracing and insulation or temporary housing shelters)
• Separate feedwater and water treatment systems and other auxiliaries can be provided to support the boiler, as needed

Skid-Mounted Boilers

• Shop-assembled package boilers, without any true mobility
• Available in capacities up to 250,000 lb/hr
• Depending on the size of the boiler, skid-mounted boilers can be transported on a flat-bed trailer, step-deck trailer, or by rail
• Cranes and/or forklifts typically required for both loading and offloading
• Not protected from the weather and precautions must be taken for freeze protection (heat tracing and insulation or temporary housing shelters)
• Separate feedwater and water treatment systems and other auxiliaries can be provided to support the boiler, as needed

Containerized Mobile Boilers

• Typically includes a package firetube boiler, installed inside a container and mounted on a chassis for mobility
• Ideal for users who need a boiler-only package that is weatherproofed for outdoor operation in the wintertime
• Separate feedwater and water treatment systems and other auxiliaries can be provided to support the boiler, as needed

Mobile Boiler Rooms

• Complete steam plants, self-contained within enclosed vans, with all equipment required to produce steam:
  • *Package firetube boiler
  • Atmospheric feedwater system
    • * Water softener
    • Chemical injection tank
    • * Blowdown separator
• Typically available in capacities up to 1,000 hp
• Weatherproofed and better suited than alternatives for outdoor operation in the wintertime

Mobile Steam Plants

• Similar to a mobile boiler room, with all equipment required to produce steam
• Equipment is installed on an open, step-deck trailer
• Not protected from the weather and precautions must be taken for freeze protection (heat tracing and insulation or temporary housing shelters)

Transportable Steam Plants

• Complete steam plant, normally built inside of a standard 20 or 40’ shipping container
• Available with either a vertical or a horizontal boiler arrangement depending on requirements
• Cranes typically required for both loading and offloading
• These systems accommodate less capacity than a mobile boiler room
• Popular for overseas and government projects, due to ease of transportation 

Each type of rental boiler system explained above has their own unique advantage and may be better fit for one user over another. The requirements of operation, however, are the same: end-users must supply a fuel source (natural gas, #2 oil, propane, or other fuel), electrical power supply, and make-up water. Which type of rental system is best fit for your unique operation?

Nationwide Boiler maintains an inventory inclusive of all types of boilers listed above, ranging in size from 47.5 hp to 200,000 lb/hr. Visit our website to find a complete listing of rental boilers available, and contact a Nationwide Boiler Sales Representative for additional details and pricing. 1-800-227-1966