Boiler Blog Archive | Nationwide Boiler Inc.

Selecting the right boiler for your facility is more than just a design choice – it directly impacts efficiency, reliability, operating costs, and emissions compliance. Among the most common designs are firetube boilers and watertube boilers, each with unique advantages depending on the application. These boilers can also be classified by pressure (low or high), output (steam or hot water), and steam temperature (saturated or superheated), adding further considerations to the decision-making process.

The following overview outlines the key differences between firetube and watertube boilers to help facility managers, engineers, and plant operators choose the system that best fits their needs.

What is a Firetube Boiler?

A firetube boiler, also known as Scotch Marine boiler, is one of the most traditional and widely used boiler designs. In this system, a large pressure vessel holds water, and tubes carrying hot combustion gases run through the vessel. As the gases pass through these tubes, heat is transferred to the surrounding water, gradually increasing its temperature until it produces either hot water or steam depending on the application. Because the “fire” or combustion gases are inside the tubes, the design is known as a firetube boiler.

Key Advantages:

Boilers are designed to produce steam to accomplish a multitude of tasks; from powering a plant to sterilizing hospital equipment. In simple terms, a boiler is a closed container in which water is heated to its boiling point to produce usable steam. In order to produce steam, there are two key items that must be involved: water and heat.

A boiler is comprised of two seperate systems: the steam-water system (waterside), and the fuel-air-flue system (fireside). As you might have guessed, water is first introduced into the waterside of the boiler. Alternatively, the fireside of the boiler provides heat, produced through the combustion of fuel (commonly natural gas or fuel oil, but can be another source) and air, which is controlled by the burner.  The heat that is created within the fireside is transferred to the waterside to produce steam.

To complete a boiler system, additional elements are required. This typically includes the following major components:

•  Burner: a mechanical device that supplies the required fuel and air for proper combustion.
•  Controls: the BMS (burner management system) protects the equipment and personnel from safety issues.
      The CCS (combustion control system) controls the air and fuel for proper combustion.
•  Fan: supplies air for the combustion to take place.
•  Water Softener: pre-treats the boiler feedwater for removal of hardness, which would otherwise cause detrimental scale
   inside the boiler system.
•  Deaerator / Feedwater System: removes oxygen and gases from boiler feedwater supply (which will also damage boiler
  internals), and feeds it to the boiler system via high pressure feedwater pumps.

All of these elements come together to create a robust steam supply system that is utilized in an abundance of processes throughout many different industries. Boilers truly are a work of art, with many pieces working as one system to make something extremely powerful and impactful, which is why we at Nationwide Boiler are so passionate about what we do.

Stay tuned for the next article in ur Boiler Basics 101 series to learn more about common types of boiler systems.  

When selecting an industrial steam boiler, it’s essential to understand the key differences between saturated steam and superheated steam boilers. These two steam classifications play distinct roles across industries, ranging from heating processes to power generation. In this guide, we’ll explore the science behind saturated and superheated steam, advantages and disadvantages of each, and how to determine which type of boiler is best suited for your application.

What Is the Difference Between Saturated Steam and Superheated Steam?

Saturated steam is steam that exists at the boiling point of water and is in equilibrium with liquid water at a given pressure and temperature. It contains moisture and is often referred to as “wet steam.” Saturated steam is produced when water is heated until it begins to vaporize.

Superheated steam, on the other hand, is created by heating saturated steam beyond the boiling point without increasing pressure. Also known as “dry steam,” superheated steam has no moisture content, a lower density, and higher energy content. It remains in a gaseous state even as it cools, which makes it highly effective in certain mechanical and thermodynamic applications.

Common Industries and Applications for Each Steam Type

Companies require rental equipment for several reasons. By understanding the rental process and following the guidelines below, it is possible that the result will be both cost-effective and technically successful.

Steam Requirements - Up front planning is the most important stage when renting equipment. First, the maximum potential steam load needed must be calculated. Your steam requirement is expressed in either boiler horsepower (hp) or lb/hr (one boiler horsepower is equal to 34.5 lb/hr steam at 212°F).

Accessible Location - A location must be selected that is easily accessible for the delivery and setting of heavy machinery and one which has easy access to the building or equipment in which the steam will be required.

Utility Connections & Supply - Fuel, water and electric power connections must be easy to access and are of sufficient size to meet the needs of the rental unit. Typically, rental boilers fire natural gas, No. 2 oil, or heated No. 6 fuel. It is also important to make sure that there is sufficient fuel capacity to supply any existing units and a temporary boiler.

Equipment Supplier - When evaluating a supplier of rental equipment it is important to know if the company is a full-time, dedicated rental company with the experience, equipment and capabilities you require. In addition, the location of the company's equipment is important, helping to minimize transportation costs and travel time. It is also important to determine if the company provides start-up and installation services.
Here at Nationwide, we have boilers located throughout the United States and our service department is available 24 hours a day for technical support.

Reputable rental companies will provide complete drawings and equipment specifications in considerable detail. Such items include the total capacity and operating characteristics of the boiler, water treatment needs and requirements, emissions requirements, weather protection, performance testing, and ASME code requirements.

Proposal Evaluation - When evaluating a proposal, normal factors including payment terms, change-of-scope clauses, liability coverage, and transportation costs need to be addressed. A well written proposal should address the rate and term on the rental unit, freight costs, time and travel charges for technicians, and should specify appropriate responsibility for installation and removal costs. You should also get the warranty statement for the rental equipment.

Operating Permits - Before installation of the equipment can occur, it is necessary to arrange for any operating permits required from regulatory agencies. This includes special permits that may be required in those areas where emission limits are strictly controlled. Areas in California including the San Joaquin Valley and the South Coast require sub-10 ppm NOx requirements.

Nationwide Boiler took the lead in equipping our units with Low NOx burners and SCR systems (the CataStak). Users facing 5 ppm NOx can rest assure that we have an immediate solution.

Maintenance - To ensure continuous, safe, and trouble free performance of the unit, there are a number of regular checks and maintenance tasks which must be performed. It is important that a log sheet be kept on site for the recording of every routine check and maintenance items completed. Daily checks include an examination of all safety devices, followed by an inspection of the low-water cutoff during every shift. The entire system should also be checked for leaks and corrected immediately. The flame pattern of the burner must also be inspected to make sure the combustion devices are working efficiently. Moreover, proper boiler performance is highly dependent on following the proper feedwater treatment and correct blowdown techniques. Failure to maintain proper water chemistry is a major cause of damage to rental boilers and the single biggest rehabilitation expense.

Return Shipment - Lastly, there are certain steps that must be taken to ensure safe return of a unit to the rental company's facility. It is the responsibility of the user to have plant or local boiler shop personnel disconnect equipment after use, which includes draining and flushing all boiler lines with clean water to help minimize any chance of corrosion. A final check of the condition of the boiler should be properly documented, recorded and sent to the rental company once the equipment is shipped.

As long as you plan in advance, budget accordingly, verify connection sizes, address permitting issues, properly train operators, frequently monitor the feedwater quality, and take responsibility in maintaining the equipment once it is installed, you can be confident that the risks associated with renting equipment will be minimized and that your project will be a success.