What is a Steam Generator Boiler?
A steam generator boiler uses a single tube coil instead of many smaller diameter boiler tubes. The generator forces the flow of hot water through the tube to convert it to steam during a single pass through the coil.
The water containing coils go around the steam generator. The furnace heats the water, circulating down through the coiled tube. While travelling down, it turns to steam as it heats, and exits the boiler in a concentrated stream at a point at the bottom of the tube.
- It is generally less potent than a full boiler but it is easier to operate.
- These generators are also smaller, making them more versatile when there is limited space available.
- They are often used as auxiliary boilers because they start up very quickly, and in applications with very low load factors.
- These boilers have a compact design, single water tube, and relatively lower water content. Consequently, they can be up and running at full power in a much shorter amount of time than larger boilers. As a result, they are useful in emergency and quick demand situations.
- They generally cost less than larger boilers. For this reason, they may be more cost-appropriate for applications that do not necessarily require such high levels of steam.
- They perform well at part loads and respond quickly to changes in loads. As a result, they dramatically increase part load operating efficiency.
- The fact that they do not have pressure vessels means that in most locations, they do not require a boiler operator.
- A steam generator boiler is useful where it can give operational efficiency because it costs around 50% more for the same horsepower output than larger boilers.
Operation and Maintenance of an Industrial Boiler
An industrial Boiler is a closed pressure vessel that produces high or low-pressure steam or hot water for industrial use. Generally, there are two types of boilers used in industrial applications—Fire-tube and Water-tube boilers.
The use of a fire-tube or water-tube industrial boiler depends on the industrial process for which they are going to generate steam or hot water.
Fire-tube Industrial Boiler
Fire-tube boilers are a cylindrical vessel in which the flames in a furnace produce hot gases that pass through tubes surrounded by water. Consequently, the heat contained in the tubes transfers to the water, heating it, and producing steam.
A fired-tube industrial boiler is employed in processes that require low pressures, up to 250 PSIG. Furthermore, due to their size limitations, up to 50,000,000 BTU/hr, do not produce large amounts of steam.
The fire-tube boiler holds a firebox where flames produce hot combustion gases. A cooling jacket that contains water surrounds the firebox and connects to the long cylindrical boiler shell. The water surrounds a series of fire-tubes or flues that heat the water, generating saturated (wet) steam. That steam rises to the boiler’s highest point, called steam dome, where it accumulates.
A regulator located in the steam dome controls the exit of the steam. A series of larger flues (tubes) situated at the top of the boiler, conduct the saturated (wet) steam back, turning it into dry or superheated steam. The boiler produces superheated steam and exhaust gases, feeding a steam engine’s cylinders. Those machines turn the energy of the steam into mechanical work. The exhaust gases are recycled to preheat the water that enters the boiler, thus increasing its efficiency.
- The maintenance and cleaning operations of a fire-tube steam boiler relatively simple. They have easy access to its firesides, allowing the change of the fire tubes without further repair of the boiler.
- The control systems are less complicated than the ones on water tube boilers.
- The accessories required by a fire-tube boiler are available at economical prices, due to the relatively low pressures that they have to stand.
- They are not only easy to operate, but they are also fuel-efficient.
To know which of these boiler types is the most convenient for you, let us see what a boiler is. “A boiler is an enclosed vessel in which a fluid such as water is heated to produce steam or the vaporized form of a liquid.
The steam or hot water is then circulated through a piping system to transfer heat for various applications such as heating, power generation, and other processes.
Boilers and associated pieces of equipment are efficient heat exchange systems. However, they can be dangerous if not properly maintained and operated”.
There is a wide variety of boilers for a myriad of applications; from heating a room, to drive the turbines of a utility company. Although all of them produce steam and hot water, they have different designs, differ in their operation, and use various types of fuel.
As a result, it is convenient to know more about the boiler types available, so that you can decide which one is the most suitable for your application.
Fire-tube steam boilers are cylindrical vessels that hold water that surrounds a set of tubes conducting hot gases produced by a furnace. Consequently, the heat in the tubes transfers to the water surrounding them, producing steam.
The installation and relocation of modern fire-tube steam boilers are possible because they are available as portable packages. Also, they are easy to maintain. Nevertheless, due to the massive amounts of water at high pressure that the boiler holds, it requires safe operating procedures. The users of fire-tube boilers are industrial and commercial facilities whose processes demand lower steam pressures from this type of boilers.
Water-tube boilers are highly efficient machines that, by their design, produce superheated dry steam at very high pressures. It feeds large amounts of vapor (several million pounds-per-hour), at very high pressures, up to 5,000 PSIG, to industrial processes. A water-tube industrial boiler has a larger size than a fire-tube.
They are the kind of boilers capable of feeding the processes of heavy industry and utility companies. However, the acquisition and installation costs are high. In the case of heavy industries, they are custom made on the installation site, which can be complicated and time-consuming. Furthermore, they are challenging to maintain. Thus, they require highly skilled personnel for operation and maintenance.
Commercial boilers have different ways to generate heat; firetube, small water tube, and electric resistance. Their ideal users are universities, libraries, office buildings, schools, laundries, hospitals, and other similar facilities,
Among the different boiler types, commercial boilers are some of the most diverse. These units can use propane, natural gas, electricity, or light oil to provide hot water or steam for process requirements or comfort heating. Based on the type of boiler selected and its application, these systems boost fuel efficiency as high as 99%.
A central heating boiler’s size is proportional to the size of the facility. The ideal size for a boiler is one that can cope adequately with the heating needs the coldest season of the year. A typical commercial heating system has four main components: The boiler produces the heat. The pipes, pumps, and valves, distribute the heat. Radiators and convectors, irradiate the heat to the specific room. Finally, there is a control system that regulates everything
- Condensing Boilers
Condensing boilers typically extract over 90% of the heat from the fuel they burn, making them both cost-effective and energy-efficient.
- Combination Boilers
A combination boiler is a type of condensing boiler. They are highly efficient and compact, making them ideal for smaller homes. They can act as both, a water heater and also a central heating unit.
- System Boilers
A system boiler directly heats a house’s central heating and also produces hot water for the storage cylinder. It is a heat-only boiler.
Boiler Types by fuel consumption
Another way that boilers can be classified is by the type of fuel that they burn. The most common are:
Most industrial coal-fired boilers run on crushed or pulverized coal, which burns more efficiently than large coal clumps.
- Gas and Oil
Gas-fired boilers operate using natural gas, most often a mix of methane, ethane, butane, pentane, or propane. Oil-fired boilers burn gasoline, diesel, and other fossil fuels.
Biomass boilers burn plant materials like wood chips, wood construction debris, and corn husks.
Boiler Types by Combustion System
All the boilers mentioned before typically fall into one of the following combustion method categories.
- Thermic Fluid
Thermic fluid heaters use fossil fuel inside a closed system. The sealed system can lead to greater efficiency, although it is not ideal for specific applications.
- Fluidized Bed
It is the most common method used for burning solid fuels in boilers today; fluidized bed technology involves a bubbling hot mixture of water and material particles (like sand) with fuel in suspension. This mix allows for rapid heat transfer and cleaner, more efficient operations.
If you need one of these boiler types, Teems Steam will provide solutions for all of your boiler sales, installation, Service, Spares and operation needs. Visit us at www.thermea-equipment.com
Water-tube Industrial Boiler
A water-tube industrial boiler has a larger size than a fire-tube. It feeds large amounts of steam (several million pounds-per-hour), at very high pressures up to 5,000 PSIG, to industrial processes.
Water-tube boilers are highly efficient machines that, by their design, produce superheated dry steam at very high pressures. They are the kind of boilers capable of feeding the processes of heavy industry and utility companies.