Steam plays a prominent role in the Power Industry. When a boiler goes down, companies can be faced with a potential loss of hundreds of thousands of dollars for each minute of lost production time. Although many plants operate 24/7 without interruption, it is very likely that a temporary steam plant will be required at some point in time.
There are many factors in steam plant operation that determine the reliability and availability of steam supply. A temporary steam plant can be required for a number of reasons, including; emergency repair, planned maintenance, increased capacity requirements, equipment retrofits, and even research and development projects. It is important to be prepared for all possibilities, planned or unplanned, that can cause a disruption in production.
Preparing a contingency plan before an emergency arises is the ideal way to avoid downtime and lost production. Use the steps outlined below as a guide to preparing for a temporary steam plant rental.
Know What’s Available – And What You Need
Think about a scenario where one or all of your facility boilers have to be taken out of service unexpectedly. What is the ideal steam capacity that would be required to continue positive production? Whatever the amount, that is your ‘sweet spot’ and the minimum capacity that you should plan for when sizing your emergency boiler. The capacity requirement, typically conveyed in pounds-per-hour (lbs/hr) or horsepower (hp), must be determined ahead of time and provided to the supplier for proper selection of a rental boiler.
Most dedicated rental boiler companies have equipment in a range of sizes and configurations. There are four major types of rental boilers on the market today:
- mobile steam plants that typically consist of a firetube boiler, feedwater system, water softener and blowdown separator, with all equipment pre-piped and wired and mounted on an open trailer or in an enclosed, semi-trailer van or container
- trailer-enclosed boilers, typically package firetube boilers only, mounted inside an enclosed semi-trailer van or container
- trailer-mounted boilers, typically watertube, mounted to a dedicated trailer for mobility
- skid-mounted boilers, which can be firetube, watertube or electric steam, and will require forklifts and/or cranes for offloading and placing at the jobsite
Generally, firetube rental boilers range in size from 50 to 1,000 hp, while watertube rental boilers are larger and typically range from 30,000 to 250,000 lbs/hr. In addition, watertube rental boilers can be built to supply either saturated or superheated steam. With the current largest trailer-mounted boilers providing 110,000 lbs/hr of superheated steam and 125,000 lbs/hr of saturated steam, you can rent multiple boilers in parallel to meet your desired capacity if one unit is not sufficient.
Most rental boiler systems will consist of the following items: boiler, burner, combustion controls, safety valves, FD fan and motor with starter, blowdown valves, feedwater stop and check valves, feedwater controls, steam gauge and other trim, flame safeguard system, and non-return valve. Piping and other items required for installation are furnished by the customer or the installer.
Understand Your Unique Operating Requirements
Operating pressure, fuel source, and available power are three additional factors that the supplier will need to know to provide the correct equipment for your process.
Most rental boilers on the market today are capable of firing on natural gas, #2 oil, or propane. Burners can often be configured to run on refinery and other fuels as well, however, increases in emissions and other operational effects must be considered.
Be sure to note your power requirements to ensure you have enough supply for the rental boiler. Rental boiler systems are commonly configured with a 480V single-point connection.
Other information that will be required by your supplier includes:
- Steam temperature: does your process require saturated or superheated steam?
- Available gas pressure: your supplier can provide a stand-alone gas regulator if the incoming pressure is higher than that required of the rental boiler.
- Water source & treatment plan: rental customers must ensure that the water going into the boiler has been treated properly to avoid damage to the internals.
Do you Need Auxiliary Rental Equipment or Other Services?
Water treatment is vital to the life of all boilers, whether it is a permanent system installed in your facility or a temporary boiler that will eventually be removed from your site.
If your support equipment is down or in a location distant to the rental boiler, you should inquire about additional options to complete the steam plant. Most companies also maintain a variety of ancillary equipment to support their fleet of rental boilers. For example, Nationwide Boiler’s rental inventory includes mobile feedwater trailers, high-pressure deaerators, water softening systems, blowdown heat recovery units, CataStak™ SCR systems, EconoStak economizers, and more.
Most rental boiler suppliers provide additional services for their customers as well. This might include equipment engineering services, parts and accessories, drawings and specifications, shipping arrangements, operation and maintenance manuals, start-up technicians and operator training, and even full-time operators when needed. Working with a company that maintains both rental boilers, support equipment, and other services will ensure that you have a plethora of options when equipment is down.
Identify the Installation Location
The location of the temporary boiler should be easily accessible to all required utility connections (water, fuel and power), and should be able to support the weight of the boiler. Compare site and equipment dimensions, and watch for obstructions that can hinder entry of the rental boiler. Keep in mind that a skid-mounted rental boiler may require a special foundation, in addition to crane handling and special rigging.
Factor in Travel Time
Some rental boiler suppliers have multiple locations for equipment maintenance and storage to help minimize transportation costs and travel time. While some mobile boilers do not require road permits, large, heavy boiler systems will require a permit to move across the road. This will add time to the delivery schedule. In addition, loose items such as gas regulators, economizers and auxiliary equipment may require a separate trailer or flat bed for shipment.
Plan for Boiler Maintenance and Weatherproofing as Needed
To ensure continuous, safe, and trouble-free performance, daily checks and routine maintenance must be performed during normal operation of the rental equipment. This includes inspection of all safety devices and low-water cutoffs during every shift. Feedwater treatment and blowdown services must also be performed to ensure proper boiler performance.
If you live in an area with freezing temperatures, prepare to weatherproof your rental boiler. If you don’t, be aware that you will be responsible for any repairs caused by freeze damage. The rental boiler supplier should be able to provide you with maintenance instructions as well as freeze protection recommendations prior to your rental.
Installation & Permitting a Rental Boiler
Boiler rental companies provide the rental equipment, but typically they do not install it. Find a local reputable contractor with boiler installation experience to install your rental equipment. Detailed drawings and data to aid in the installation process will be supplied by the rental company.
Both construction and air permits are required by every state before installing a rental boiler, but specific requirements differ by location. Be aware that some permits take months to sort out, so the sooner you can begin the process the better.
If your emissions requirements are 15 ppm NOx or less, look for a supplier who can offer an SCR system rental or an ultra low NOx boiler. Nationwide Boiler offers ultra-low NOx mobile boiler rooms and CataStak™ SCR systems for watertube boilers to comply with ultra-low NOx limits. The company also maintains an inventory of per-permitted boilers for customers in the Southern California region – a location with the most stringent air emissions requirements in the country.
Plan and Research Before Choosing a Supplier
Choosing a reputable and reliable rental boiler supplier is a step that some would consider the most important in this process. Taking the time to actually visit your chosen supplier can provide valuable intel on their equipment, capabilities, and quality of workmanship.
Understanding the responsibilities of the customer vs. the supplier is another important step. A signed rental agreement, purchase order, deposit and proof of insurance coverage will generally be required before delivery takes place. A well written rental agreement will carefully outline customer responsibilities and liabilities.
Lastly, be sure to consider whether the company is a full-time, dedicated rental company with experience, reliable equipment, and the capabilities to handle your project. Be cautious of firms without a purpose-built rental fleet.
The preparation time required to create a contingency plan is minimal when compared to the possible production, time, and money lost when an emergency arises. As the saying goes, hope for the best but plan for the worst. It will be well worth it in the long run. Download Nationwide Boiler’s emergency preparedness plan to get on track and prepared for your next planned or unplanned temporary steam need.