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:

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

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

Established in 1967 by late founder and pioneer Dick Bliss, Nationwide Boiler began with a mission to provide mobile, temporary boilers to steam users during planned and unplanned boiler outages. At the time, our rental fleet wasn’t much of a ‘fleet’ and consisted of just one 20,000 lb/hr trailer-mounted, O-type watertube boiler. Throughout the years, our inventory has grown to consist of over 100 rental boilers and related equipment, all with various specifications and capabilities. And with multiple storage locations throughout the country, we are capable of shipping our boilers to customers not just nationwide, but worldwide.

With a goal of being the #1 emergency boiler supplier, we understand the importance of educating steam users on emergency preparedness and the benefits of utilizing a rental boiler not just during emergencies, but also during planned outages and periods of high demand.

Reasons to Rent a Boiler

• Unforeseeable Situations
  •  A boiler shuts down unexpectedly, needing maintenance and/or repairs
  •  Disasters and natural causes that lead to a temporary steam need

Nationwide Boiler has come to the rescue in many emergency situations. One notable instance was the tragedy on September 11^th, 2001, where we responded quickly to assist ConEd with the supply of heat to New York city. 

• Increase in Demand
  • Companies face periods of increased demand due to varying factors, requiring additional steam capacity

Nationwide Boiler has a great deal of experience renting boilers when additional steam is needed. In fact, we have an annual rental with a tomato processing company to support their seasonal increase in demand.