|A boiler is a closed vessel in which water or other liquid is heated. The fluid does not boil. (In North America, the word "furnace" is generally used if the reason is not to boil the liquid.) The warmed or vaporized fluid exits the boiler for use in various procedures or heating applications,[1 - [2 - including drinking water heating, central heating, boiler-based power era, cooking, and sanitation.
The pressure vessel of the boiler is usually manufactured from steel (or alloy steel), or historically of wrought iron. Stainless steel, especially of the austenitic types, is not found in wetted elements of boilers due to corrosion and stress corrosion breaking.[3 - However, ferritic stainless steel is often used in superheater sections that won't come in contact with boiling drinking water, and electrically heated stainless steel shell boilers are allowed under the Western "Pressure Equipment Directive" for creation of steam for sterilizers and disinfectors.[4 -
https://en.wikipedia.org/wiki/Boiler - https://en.wikipedia.org/wiki/Boiler
In live steam models, copper or brass is often used since it is more fabricated in smaller size boilers easily. Historically, copper was often used for fireboxes (especially for vapor locomotives), due to its better formability and higher thermal conductivity; however, in newer times, the high price of copper often makes this an uneconomic choice and cheaper substitutes (such as metal) are used instead.
For a lot of the Victorian "age group of vapor", the only material used for boilermaking was the highest quality of wrought iron, with assembly by rivetting. This iron was from specialist ironworks, such as at Cleator Moor (UK), noted for the high quality of their rolled plate and its suitability for high-reliability use in critical applications, such as high-pressure boilers. In the 20th century, design practice transferred towards the use of steel instead, which is more powerful and cheaper, with welded building, which is quicker and requires less labour. It ought to be noted, however, that wrought iron boilers corrode far slower than their modern-day steel counterparts, and are less susceptible to localized pitting and stress-corrosion. This makes the longevity of old wrought-iron boilers much more advanced than those of welded steel boilers.
Cast iron may be used for the heating system vessel of home drinking water heaters. Although such heaters are usually termed "boilers" in a few countries, their purpose is to create hot water usually, not steam, and they also run at low pressure and try to avoid boiling. The brittleness of cast iron helps it be impractical for high-pressure steam boilers.
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The source of heat for a boiler is combustion of some of several fuels, such as wood, coal, oil, or gas. Electric vapor boilers use level of resistance- or immersion-type heating system elements. Nuclear fission is also used as a heat source for producing steam, either straight (BWR) or, in most cases, in specialised temperature exchangers called "steam generators" (PWR). Heat recovery vapor generators (HRSGs) use the heat rejected from other processes such as gas turbine.
there are two solutions to measure the boiler efficiency 1) direct method 2) indirect method
Direct method -immediate approach to boiler efficiency test is more functional or even more common
boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total vapor movement Hg= Enthalpy of saturated vapor in k cal/kg Hf =Enthalpy of feed drinking water in kcal/kg q= level of fuel use in kg/hr GCV =gross calorific value in kcal/kg like family pet coke (8200 kcal/KG)
indirect method -to gauge the boiler efficiency in indirect method, we need a following parameter like
Ultimate analysis of gasoline (H2,S2,S,C moisture constraint, ash constraint)
percentage of O2 or CO2 at flue gas
flue gas temperature at outlet
ambient temperature in deg c and humidity of air in kg/kg
GCV of gasoline in kcal/kg
ash percentage in combustible fuel
GCV of ash in kcal/kg
Boilers can be classified into the following configurations:
Pot boiler or Haycock boiler/Haystack boiler: a primitive "kettle" where a fire heats a partially filled water pot from below. 18th century Haycock boilers produced and stored large quantities of very low-pressure vapor generally, barely above that of the atmosphere often. These could burn wood or frequently, coal. Efficiency was suprisingly low.
Flued boiler with one or two large flues-an early forerunner or type of fire-tube boiler.
Diagram of a fire-tube boiler
Fire-tube boiler: Here, drinking water partially fills a boiler barrel with a little volume remaining above to accommodate the steam (vapor space). This is the kind of boiler used in all steam locomotives nearly. The heat source is inside a furnace or firebox that has to be kept completely surrounded by water in order to keep the temperatures of the heating surface below the boiling point. The furnace can be situated at one end of a fire-tube which lengthens the path of the hot gases, thus augmenting the heating surface which can be further increased by making the gases invert direction through a second parallel tube or a bundle of multiple pipes (two-pass or come back flue boiler); on the other hand the gases may be taken along the sides and then under the boiler through flues (3-move boiler). In case of a locomotive-type boiler, a boiler barrel extends from the firebox and the hot gases pass through a bundle of fire tubes inside the barrel which greatly escalates the heating surface in comparison to a single pipe and further boosts heat transfer. Fire-tube boilers have a comparatively low rate of steam production usually, but high steam storage capacity. Fire-tube boilers mainly burn off solid fuels, but are readily adaptable to people of the gas or liquid variety.
Diagram of the water-tube boiler.
Water-tube boiler: In this type, pipes filled with water are arranged in the furnace in a true number of possible configurations. Water tubes connect large drums Often, the low ones formulated with drinking water and the upper ones steam and water; in other situations, such as a mono-tube boiler, drinking water is circulated with a pump through a succession of coils. This kind generally gives high steam creation rates, but less storage capacity than the above. Water pipe boilers can be made to exploit any warmth source and are generally preferred in high-pressure applications because the high-pressure drinking water/steam is included within small size pipes which can withstand the pressure with a thinner wall structure.
Flash boiler: A flash boiler is a specialized kind of water-tube boiler in which pipes are close jointly and drinking water is pumped through them. A flash boiler differs from the kind of mono-tube steam generator where the tube is permanently filled with water. Super fast boiler, the pipe is kept so hot that water give food to is quickly flashed into steam and superheated. Flash boilers acquired some use in cars in the 19th century which use continued into the early 20th century. .
1950s design steam locomotive boiler, from a Victorian Railways J class
Fire-tube boiler with Water-tube firebox. Sometimes the two above types have been mixed in the next manner: the firebox contains an assembly of water tubes, called thermic siphons. The gases go through a typical firetube boiler then. Water-tube fireboxes were installed in many Hungarian locomotives,[citation needed - but have fulfilled with little success in other countries.
Sectional boiler. Within a solid iron sectional boiler, sometimes called a "pork chop boiler" water is included inside solid iron areas.[citation needed - These areas are assembled on site to produce the finished boiler.
See also: Boiler explosion
To define and secure boilers safely, some professional specialized organizations such as the American Society of Mechanical Technical engineers (ASME) develop standards and regulation codes. For instance, the ASME Boiler and Pressure Vessel Code is a typical providing a wide range of guidelines and directives to ensure compliance of the boilers and other pressure vessels with security, design and security standards.[5 -
Historically, boilers were a way to obtain many serious injuries and property destruction as a consequence to badly understood engineering principles. Thin and brittle steel shells can rupture, while welded or riveted seams could start badly, leading to a violent eruption of the pressurized steam. When water is changed into vapor it expands to over 1,000 times its original quantity and travels down vapor pipes at over 100 kilometres each hour. Because of this, vapor is a superb way of moving energy and temperature around a site from a central boiler house to where it is needed, but without the right boiler feed water treatment, a steam-raising place are affected from scale development and corrosion. At best, this increases energy costs and can result in poor quality vapor, reduced efficiency, shorter plant life and unreliable operation. At worst, it can lead to catastrophic reduction and failure of life. Collapsed or dislodged boiler tubes can also aerosol scalding-hot steam and smoke from the air intake and firing chute, injuring the firemen who weight the coal into the open fire chamber. Extremely large boilers providing hundreds of horsepower to operate factories could demolish entire structures.[6 -
A boiler that has a loss of give food to water and is permitted to boil dry can be hugely dangerous. If supply drinking water is sent in to the unfilled boiler then, the tiny cascade of inbound drinking water instantly boils on contact with the superheated metallic shell and leads to a violent explosion that cannot be controlled even by basic safety steam valves. Draining of the boiler can also happen if a leak occurs in the vapor source lines that is bigger than the make-up water supply could replace. The Hartford Loop was created in 1919 by the Hartford Steam Boiler and INSURANCE PROVIDER as a method to help prevent this problem from taking place, and therefore reduce their insurance promises.[7 - [8 -
Superheated steam boiler
A superheated boiler on the steam locomotive.
Main article: Superheater
Most boilers produce vapor to be utilized at saturation heat; that is, saturated steam. Superheated steam boilers vaporize the water and additional heat the steam in a superheater then. This provides vapor at higher temperature, but can decrease the overall thermal efficiency of the steam generating vegetable because the higher vapor heat range requires a higher flue gas exhaust temperatures.[citation needed - There are several ways to circumvent this issue, typically by giving an economizer that heats the give food to drinking water, a combustion air heating unit in the hot flue gas exhaust path, or both. You can find advantages to superheated steam that may, and will often, increase overall efficiency of both steam generation and its utilization: benefits in input temperatures to a turbine should outweigh any cost in additional boiler complication and expense. There could be useful limitations in using wet vapor also, as entrained condensation droplets will harm turbine blades.
Superheated steam presents unique safety concerns because, if any operational system component fails and allows steam to flee, the ruthless and temperature can cause serious, instantaneous harm to anyone in its path. Since the escaping steam will be completely superheated vapor, detection can be difficult, although the intense heat and sound from such a leak indicates its existence clearly.
Superheater procedure is similar to that of the coils on an fresh air conditioning unit, although for a different purpose. The steam piping is directed through the flue gas route in the boiler furnace. The temperature in this field is between 1 typically,300 and 1,600 °C (2,372 and 2,912 °F). Some superheaters are glowing type; that is, they absorb high temperature by radiation. Others are convection type, absorbing warmth from a liquid. Some are a mixture of both types. Through either method, the extreme heat in the flue gas path will heat the superheater steam piping and the steam within also. While the heat range of the vapor in the superheater rises, the pressure of the vapor does not and the pressure remains the same as that of the boiler.[9 - Virtually all steam superheater system designs remove droplets entrained in the steam to avoid harm to the turbine blading and associated piping.
Supercritical steam generator
Boiler for a charged power place.
Main article: Supercritical steam generator
Supercritical steam generators are used for the production of electric power frequently. They operate at supercritical pressure. As opposed to a "subcritical boiler", a supercritical steam generator operates at such a higher pressure (over 3,200 psi or 22 MPa) that the physical turbulence that characterizes boiling ceases that occurs; the fluid is neither liquid nor gas but a super-critical liquid. There is absolutely no era of steam bubbles within the water, because the pressure is above the critical pressure point at which vapor bubbles can develop. As the liquid expands through the turbine stages, its thermodynamic condition drops below the critical point as it does work turning the turbine which converts the power generator that power is eventually extracted. The fluid at that time may be a mixture of steam and liquid droplets as it passes into the condenser. This results in less fuel use and therefore less greenhouse gas production slightly. The term "boiler" should not be used for a supercritical pressure steam generator, as no "boiling" occurs in this product.
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Boiler fittings and accessories
Pressuretrols to control the steam pressure in the boiler. Boilers generally have two or three 3 pressuretrols: a manual-reset pressuretrol, which functions as a safety by setting the top limit of steam pressure, the operating pressuretrol, which handles when the boiler fires to keep pressure, as well as for boilers outfitted with a modulating burner, a modulating pressuretrol which controls the quantity of fire.
Safety valve: It can be used to relieve pressure and stop possible explosion of the boiler.
Water level signals: They show the operator the amount of liquid in the boiler, known as a view glass also, water measure or drinking water column.
Bottom blowdown valves: They offer a way for removing solid particulates that condense and rest on underneath of a boiler. As the name indicates, this valve is usually located directly on underneath of the boiler, and is sometimes opened up to use the pressure in the boiler to force these particulates out.
Constant blowdown valve: This allows a small level of water to escape continuously. Its purpose is to avoid water in the boiler becoming saturated with dissolved salts. Saturation would business lead to foaming and cause water droplets to be carried over with the steam - an ailment known as priming. Blowdown is often used to monitor the chemistry of the boiler water also.
Trycock: a kind of valve that is often use to manually check a liquid level in a container. Mostly found on a drinking water boiler.
Flash tank: High-pressure blowdown enters this vessel where the vapor can 'flash' safely and become found in a low-pressure system or be vented to atmosphere as the ambient pressure blowdown moves to drain.
Automatic blowdown/continuous heat recovery system: This technique allows the boiler to blowdown only when makeup water is moving to the boiler, thereby transferring the maximum amount of heat possible from the blowdown to the make-up water. No flash tank is normally needed as the blowdown discharged is close to the heat of the makeup water.
Hand holes: These are steel plates installed in openings in "header" to permit for inspections & installing pipes and inspection of internal surfaces.
Steam drum internals, a series of screen, scrubber & cans (cyclone separators).
Low-water cutoff: It is a mechanical means (usually a float switch) that is utilized to turn from the burner or shut down fuel to the boiler to avoid it from working once the water runs below a certain point. If a boiler is "dry-fired" (burned without water in it) it can cause rupture or catastrophic failure.
Surface blowdown range: It offers a means for removing foam or other lightweight non-condensible substances that tend to float on top of water inside the boiler.
Circulating pump: It really is designed to circulate drinking water back again to the boiler after it has expelled a few of its heat.
Feedwater check valve or clack valve: A non-return stop valve in the feedwater line. This can be installed to the side of the boiler, just below the water level, or to the very best of the boiler.[10 -
Top feed: With this design for feedwater injection, the water is fed to the very best of the boiler. This may reduce boiler exhaustion triggered by thermal stress. By spraying the feedwater over a series of trays water is quickly warmed and this can reduce limescale.
Desuperheater pipes or bundles: A series of tubes or bundles of pipes in the water drum or the vapor drum made to cool superheated steam, in order to provide auxiliary equipment that will not need, or may be damaged by, dry steam.
Chemical injection line: A connection to add chemicals for controlling feedwater pH.
Main vapor stop valve:
Main vapor stop/check valve: It is used on multiple boiler installations.
Gas oil system:gasoline oil heaters
Other essential items
Inspectors test pressure measure attachment: