Boilers are industrial, commercial and domestic utilities that provide heated air and hot water in homes and businesses as well as steam for use in steam-operated machinery. The most common boiler varieties are often denominated according to their method of heat generation; gas boilers, electric boilers and oil boilers are the most widely used steam boilers.
Almost all boilers can be placed into one of those three categories (there are exceptions: Central Boiler's systems are wood fired). Combi boilers are different from conventional models because they do not store hot water but rather heat it rapidly on demand. They have a second heating element to speed the heating process and maintain a steady supply for as long as the boiler runs. Condensing boilers are able to recover energy that would normally be expelled through the flue by condensing the escaping water vapor back into liquid water. Because the boiler uses latent heat to boost its efficiency to above 90%, it is considered a high efficiency boiler. Another way to increase efficiency is through a high pressure boiler, which maintains an operating pressure greater than 15 PSI; some models achieve pressures as high as 1,000 PSI. Low pressure boilers have pressure less than 15 PSI and are used mostly in smaller buildings for heating a space. Industrial boilers are used either as part of a heating system or to individually generate hot water or steam for various industrial and manufacturing processes. They are much larger in size and built from heavy duty materials to ensure safety, durability and performance.
Boilers provide residential, commercial and industrial heating and are a key part in hydronics, which is the use of water as a heat-transfer medium. Boilers are constructed of stainless steel, aluminum or cast iron and are composed of a furnace with various heat exchanger components and a pump or fan. The two basic designs include fire-tube and water-tube boilers. Fire-tube boilers work by distributing heat through tubes immersed in water; water-tubes circulate water through heated tubes within the enclosure. Hot flue gases are passed over the tubes, heating the water, and then are discharged through a stack. Both designs are comparable in efficiency but are not interchangeable, because of structural considerations. Boilers rely on radiant heat and the transfer of thermal energy to guide the movement of the water or steam. Because heat moves from areas of high temperature to low temperature, the furnace is able to heat the tubes that heat the water, which in turn heats the pipes or radiators that heat the room; virtually the entire process relies on the behavior of high temperature fluids.
The purpose of a boiler is to provide hot water or to generate steam. Steam boilers produce steam for heating large buildings such as factories and warehouses; in other industrial applications the steam can be used for power. Hot water boilers are an important part in hydronics because they heat the water that circulates through a series of pipes and into radiators, baseboards and other heat exchangers. Boilers generally use one of three sources of fuel: gas, oil or electricity. Gas boilers are fueled by natural gas and use a natural gas flame to heat water to a specified temperature or to its boiling point, thereby producing steam. They are the most common type of boiler used for heating applications in the United States. Oil boilers use oil either as fuel for the furnace or to replace the water generally found in boilers and produce hot gases that travel through the piping system. Electric boilers offer efficient, clean and safe water heating. Unlike appliances that provide heating through the process of combustion, electric boilers eliminate the problems with carbon monoxide, back drafting, pilot lights, gas piping and venting.
Boilers have historically been used to produce steam for power. The steam locomotive and steam engine are two examples of this application. They were used industrially and were fairly dangerous, as early operators did not fully understand the relationship between temperature and pressure. Concerned citizens and workers contemplated getting rid of steam boilers altogether until advances in safety and knowledge were made. Today, boilers operate in many different settings such as schools and office buildings. The materials, design and construction have all improved to the point that fear is no longer a factor. Accidents do still occur but with less frequency and with fewer injuries or fatalities. Boilers are now an extremely valuable part of life and can be found in almost any environment. Once quite large, boilers are becoming smaller and smaller in order to fit into tight spaces, though some boilers, like those used industrially, must remain their size in order to produce the necessary amounts of steam and water. Mobile boilers are now available and can be used in military, emergency or temporary situations to provide steam for heat or power. Even as technology continues to make significant advances, boilers will most likely remain a critical part of life for years to come.
Boilers Manufacturers - Fulton Boiler Works, Inc.
Boilers - Fulton Boiler Works, Inc.
Boilers Manufacturers - Unilux Advanced Manufacturing, LLC
Boilers Manufacturers - Unilux Advanced Manufacturing, LLC
Boilers - Fulton Boiler Works, Inc.
Boilers Manufacturers - Unilux Advanced Manufacturing, LLC
Industrial boilers have been an important device in number of industries since they were first used in steam engines. Steam engines may have been phased out, however, boilers are still extensively used for various industries, ranging from laundry to food, and from sewer maintenance to breweries.
Industrial boilers' working principle is the same as pressure cookers in your kitchen. The difference is in the scale and ability to withstand high pressure. They are specially designed to manage pressure as high as 30 bars, and are thus made from chunky steel plates that are welded together. However, just like pressure cookers, they are enclosed vessels made to withstand high pressures and to heat water by a fuel source. The steam generated by the boilers is used for humidification and for industrial heating. In the times of steam engines, the steam was used to expand the cylinder, which moved the piston, giving momentum to engine.
Construction of a standard boiler
An industrial boiler consists of a heating chamber, also known as a vessel, which typically is in the shape of a cylinder. In the cylinder, a heating source in the form of a burner is installed, and the heat produced by the burner is transferred to the water. The heat is transferred by the heat exchanger, which includes pipes and tubes to transfer the steam to the desired end. When hot water is the requirement rather than steam, pumps are usually employed. The steam moves under its own pressure and is transported to the desired place with a cache of tubes. To make boilers work efficiently with less water loss, the condensed steam is returned back to the furnace to be heated again, and the furnace is furnished with water continuously to compensate for the lost water. The other parts include a chimney to emit combustion gases, and a pressure safety mechanism.
Application of industrial boilers
Industrial boilers consume huge amounts of energy, thus, it is important that they run efficiently in order to be cost effective. A single parameter cannot determine the efficiency of an industrial boilers; therefore, a number of things need to be considered before buying a boiler.
Combustion efficiency versus thermal efficiency
For industrial boilers, two types of efficiencies are normally used, one is the combustion efficiency and the other is thermal efficiency. So what is the difference between them?
In a combustion process, chemical potential energy of a fuel is changed or converted to produce thermal energy, and the percentage of potential energy that is converted is defined as the combustion efficiency. Whereas, the thermal efficiency is the percentage of potential fuel energy converted to thermal energy for producing steam or heated water. While looking into the efficiency of industrial boilers, it is advised to check the thermal efficiency, not the combustion efficiency.
The other parameter that defines the efficiency of boilers and heating system efficiency is the boiler controllability. It is reported that for maximum boiler efficiency, the boiler controllability, which also is known as turn down ratio, should be considered.
With the advent of stricter environmental regulations, it is important that you consider the rules and codes implemented regarding boilers. The rules that you must research, include the American Society of Mechanical Engineers rules, insurance guidelines, and state rules regarding boilers.
A system load is measured at specific temperature and pressure in terms of Btus or pounds of steam. Typically, there are three types of loads, heating load, process load, and combination load. System load helps to select the size of a boiler that will serve the requirement.
Single or multiple boilers
While selecting a boiler, considering a back-up for the boiler is important. However, some systems do not need a backup; those are usually not associated with production. Moreover, emergency repairs, future expansion and maintenance should be considered.
In a standard operation, almost 10 percent of an operating budget goes to fuel, thus fuel options must be deeply considered. You can choose from a number of fuel sources, including propane, natural gas and light oil. Fuel such as heavy oil and solid fuels are being phased out under new guidelines. Natural gas is recommended, as the best fuel as it leaves few residues, which determines maintenance cost.
Parameters that you need to calculate
For understanding how a boiler will perform over time, it is important to estimate number of things, including boiler-fuel consumption rate, annual fuel use, annual fuel cost, and potential annual fuel savings. After estimating all these parameters, you need to determine potential incremental efficiency, as well as, what will be the payback period against the investment.
The factors and parameters discussed for industrial boilers need further research to understand how they all together and individually affect the performance of a boiler. Therefore, it is recommended to review the literature given in American Society of Mechanical Engineers (ASME), which explores the factors with better insight.
With the number of options available on the market, choosing an industrial boiler can be a daunting task. Boilers may look like large pressure cooking units; however, they are complex devices with varying designs to serve different purposes. The best way to select a suitable boiler is to look at two factors, the application and design.
The primary decision that you have to make is regarding the application, since boilers are used either for hot water or for steam generation. This is how boilers are classified. Hot water boilers provide hot water for heating systems, which are commonly used for providing optimum room temperature, used as protection against freezing, for dishwashing at large scales, car washing, along with many other applications. Whereas, industrial boilers, that generate steam, have application in power generation, cement and brick production, as well as soil steaming in agriculture.
All standard boilers have a furnace. The heat exchanger distinguishes one from another design. In general, three types of boilers are available, with different heat exchangers.
In this design, water tubes are installed in the boiler drum. When the water filled tubes are exposed to heated gases, the water boils and evaporates to make steam. This type of boiler is more thermally efficient and saves a significant amount of energy. However, the design has downfalls too. First, their construction is complex. Second, the water fed into the system needs to be treated, since water with contaminants can clog tubes; all solids in the water are required to be filtered out before water enters the boiler. This design is preferred when the demand of the steam is high and when high pressure is required, therefore, they are also called high pressure boilers.
Fire Tube Boilers
As the name implies, tubes carrying hot gases from the furnace pass through the water-filled drum to generate steam. This design is a common construction found in the industry and is relatively easy to operate compared to the water-tube design. Unlike the water tube design, they are not complex, which makes them less expensive than the alternative. However, they are bulky because of the chunky outer shell. The design is used when low pressure steam is required, thus they are also known as low-pressure boilers. This design has evolved over time and three variations are available on the market. The first is the horizontal return tubular boiler, which has a horizontal tubes and a separated furnace. The second design is known as scotch marine or shell boilers, in which both the fire-tubes and combustion chamber are designed in a single shell. The last variation is known as firebox boilers, which has a specialized water-jacketed firebox.
Sectional Boilers have the most basic design, in which different sections are casted and bolted together. The combustion chamber surrounds the water chamber and heat is exchanged directly. The boilers are used for hot water needs, since it is made from cast iron.
The last option that you can come across is the hybrid design, which uses a different arrangement of heat exchangers and combustion chamber to achieve high efficiency.
- A test that measures the relieving capacity of boiler safety relief
- The air that surrounds the equipment.
- A burner in which the fuel, in either a gaseous or finely divided form, is burned in suspension. The air for combustion is supplied by bringing it into contact with the fuel as it is drawn through one or more openings by the lower static pressure created by the velocity of the fuel stream.
- The removal of a boiler from service for a length of time. A boiler may be laid-up dry or wet.
- Pressure of the steam of water in a boiler, generally expressed in pounds per square inch (psi) and corresponding temperature.
- A valved port used to vent air from a full boiler and to prevent a vacuum from forming when the boiler is drained. Boiler vent openings are located on the highest part of the waterside of the boiler.
- The draining of a portion of the water in the boiler in order to remove the heavy sludge that tends to settle at the bottom. This process is done periodically.
- Amount of heat needed to raise or lower the temperature of one pound of water by one degree Fahrenheit under standard pressure.
- A pipeline that passes around a control in order to allow the boiler to be operated manually without having to use the control.
- A small, continuously draining stream of water that controls the quantities of impurities in a boiler.
- A pressure control setting at which the boiler automatically turns on.
- Connections between parts of a boiler to equalize pressures.
- A door in a furnace or boiler setting that is designed to be opened by a pre-determined gas pressure.
- The lowest temperature at which, under specified conditions, fuel oil gives off enough vapor to flash into a momentary flame when ignited.
- An enclosed space of a boiler in which the fuel undergoes combustion.
- A flame which is utilized to ignite the fuel at the main burner or burners.
- A vertical conduit that, due to the difference in density between internal and external gases, creates a draft at its base.
- The vapor phase of water, unmixed with other gases.
- The change from liquid or solid phase to the vapor phase.