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  • JamesTic - A boiler is a closed vessel where drinking water or other liquid is heated. The fluid will not boil. (In THE UNITED STATES, the term “furnace” is generally used if the reason is never to boil the liquid.) The warmed or vaporized fluid exits the boiler for use in various processes or heating applications,[1 – [2 – including drinking water heating, central heating, boiler-based power generation, cooking food, and sanitation.

    The pressure vessel of the boiler is usually made of steel (or alloy steel), or historically of wrought iron. Stainless steel, especially of the austenitic types, is not found in wetted parts of boilers thanks to stress and corrosion corrosion breaking.[3 – However, ferritic stainless steel is often found in superheater sections that will not be exposed to boiling drinking water, and electrically heated stainless steel shell boilers are allowed under the Western “Pressure Equipment Directive” for production of steam for sterilizers and disinfectors.[4 –
    In live steam models, copper or brass is often used because it is easier fabricated in smaller size boilers. Historically, copper was often used for fireboxes (especially for vapor locomotives), because of its better formability and higher thermal conductivity; however, in more recent times, the high price of copper often makes this an uneconomic choice and cheaper substitutes (such as steel) are used instead.

    For much of the Victorian “age of steam”, the only materials used for boilermaking was the best quality of wrought iron, with assembly by rivetting. This iron was often from specialist ironworks, such as at Cleator Moor (UK), mentioned 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 instead transferred towards the use of metal, which is more powerful and cheaper, with welded construction, 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 older wrought-iron boilers far more advanced than those of welded metal boilers.

    Cast iron might be utilized for the heating system vessel of local drinking water heaters. Although such heaters are usually termed “boilers” in some countries, their purpose is usually to produce warm water, not steam, and so they run at low pressure and stay away from 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 any of several fuels, such as wood, coal, oil, or gas. Electric steam boilers use resistance- or immersion-type heating elements. Nuclear fission is utilized as a heat source for generating steam also, either directly (BWR) or, generally, in specialised high temperature exchangers called “vapor generators” (PWR). Heat recovery steam generators (HRSGs) use the heat rejected from other procedures such as gas turbine.

    Boiler efficiency
    there are two solutions to measure the boiler efficiency 1) direct method 2) indirect method

    Direct method -immediate method of boiler efficiency test is more useful or more common

    boiler efficiency =Q*((Hg-Hf)/q)*(GCV *100 ) Q =Total vapor movement Hg= Enthalpy of saturated steam in k cal/kg Hf =Enthalpy of give food to drinking water in kcal/kg q= level of gasoline use in kg/hr GCV =gross calorific value in kcal/kg like family pet coke (8200 kcal/KG)

    indirect method -to measure the boiler efficiency in indirect method, we are in need of a following parameter like

    Ultimate analysis of energy (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 gas in kcal/kg
    ash percentage in combustible fuel
    GCV of ash in kcal/kg
    Boilers can be classified in to the following configurations:

    Container boiler or Haycock boiler/Haystack boiler: a primitive “kettle” in which a open fire heats a partially filled water pot from below. 18th century Haycock boilers produced and stored large volumes of very low-pressure vapor generally, hardly above that of the atmosphere often. These could burn off wood or most often, coal. Efficiency was very low.
    Flued boiler with one or two large flues-an early type or forerunner 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 still left above to support the vapor (vapor space). This is the type of boiler used in all steam locomotives nearly. The heat source is inside a furnace or firebox that needs to be kept completely surrounded by the water in order to keep the temp of the heating surface below the boiling point. The furnace can be situated at one end of the fire-tube which lengthens the path of the hot gases, thus augmenting the heating surface which may be further increased by causing the gases reverse direction through a second parallel tube or a lot of money of multiple pipes (two-pass or return flue boiler); alternatively the gases may be taken along the edges and then under the boiler through flues (3-pass boiler). In case there is a locomotive-type boiler, a boiler barrel stretches from the firebox and the hot gases go through a lot of money of fire pipes inside the barrel which greatly escalates the heating system surface in comparison to a single tube and further increases heat transfer. Fire-tube boilers usually have a comparatively low rate of vapor creation, but high steam storage capacity. Fire-tube boilers burn solid fuels mostly, but are readily adaptable to people of the gas or water variety.

    Diagram of a water-tube boiler.
    Water-tube boiler: In this type, pipes filled up with drinking water are arranged in the furnace in a true variety of possible configurations. The water tubes connect large drums Often, the lower ones containing water and the top ones steam and water; in other situations, like a mono-tube boiler, drinking water is circulated with a pump through a succession of coils. This type generally gives high steam creation rates, but less storage space capacity than the above mentioned. Water tube boilers can be designed to exploit any temperature source and are generally preferred in high-pressure applications since the high-pressure drinking water/vapor is contained within small size pipes which can withstand the pressure with a thinner wall.
    Flash boiler: A flash boiler is a specialized kind of water-tube boiler where tubes are close collectively and drinking water is pumped through them. A flash boiler differs from the type of mono-tube steam generator in which the tube is permanently filled up with water. Super fast boiler, the tube is held so hot that water feed is quickly flashed into steam and superheated. Flash boilers had some use in automobiles in the 19th century which use continued into the early 20th century. .

    1950s design vapor locomotive boiler, from a Victorian Railways J class
    Fire-tube boiler with Water-tube firebox. Sometimes the two above types have been combined in the next manner: the firebox contains an assembly of water tubes, called thermic siphons. The gases pass through a typical firetube boiler then. Water-tube fireboxes were installed in many Hungarian locomotives,[citation needed – but have fulfilled with little success far away.
    Sectional boiler. Within a solid iron sectional boiler, sometimes called a “pork chop boiler” water is included inside cast iron areas.[citation needed – These sections are assembled on site to create the finished boiler.
    See also: Boiler explosion
    To define and secure boilers safely, some professional specialized organizations like the American Culture of Mechanical Technicians (ASME) develop requirements and regulation codes. For instance, the ASME Boiler and Pressure Vessel Code is a standard providing a wide range of rules and directives to ensure compliance of the boilers and other pressure vessels with safety, design and security standards.[5 –

    Historically, boilers were a source of many serious injuries and property destruction due to poorly understood engineering principles. Thin and brittle steel shells can rupture, while badly welded or riveted seams could open up, leading to a violent eruption of the pressurized steam. When water is converted to steam it expands to over 1,000 times its original volume and travels down vapor pipes at over 100 kilometres each hour. As a result of this, vapor is a great way of moving energy and heat around a site from a central boiler house to where it is necessary, but with no right boiler give food to water treatment, a steam-raising vegetable are affected from range corrosion and formation. At best, this raises energy costs and can result in poor quality steam, reduced efficiency, shorter plant life and unreliable procedure. At worst, it can lead to catastrophic failing and loss of life. Collapsed or dislodged boiler pipes can also spray scalding-hot vapor and smoke from the air intake and firing chute, injuring the firemen who insert the coal into the open fire chamber. Extremely large boilers providing hundreds of horsepower to operate factories could demolish entire buildings.[6 –

    A boiler that has a loss of feed water and is permitted to boil dry can be extremely dangerous. If supply drinking water is sent in to the empty boiler then, the tiny cascade of inbound drinking water instantly boils on connection with the superheated metallic shell and leads to a violent explosion that can’t be controlled even by security steam valves. Draining of the boiler can also happen if a leak occurs in the steam source lines that is larger than the make-up drinking water source could replace. The Hartford Loop was developed in 1919 by the Hartford Vapor Boiler and INSURANCE PROVIDER as a strategy to help prevent this problem from occurring, and thereby reduce their insurance claims.[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 vapor. Superheated steam boilers vaporize the water and additional heat up the steam in a superheater then. This provides vapor at much higher temp, but can reduce the overall thermal efficiency of the steam generating herb because the bigger steam temperatures takes a higher flue gas exhaust heat range.[citation needed – There are several ways to circumvent this issue, by providing an economizer that heats the feed water typically, a combustion air heating unit in the hot flue gas exhaust route, or both. You can find advantages to superheated steam that may, and will often, increase overall efficiency of both vapor generation and its own utilization: gains in input heat to a turbine should outweigh any cost in additional boiler complication and expense. There can also be practical restrictions in using moist steam, as entrained condensation droplets will damage turbine blades.

    Superheated steam presents unique safety concerns because, if any system component fails and allows steam to flee, the high temperature and pressure can cause serious, instantaneous injury to anyone in its path. Since the escaping steam will initially be completely superheated vapor, detection can be difficult, although the extreme heat and sound from such a leak obviously indicates its presence.

    Superheater procedure is similar to that of the coils on an fresh air conditioning unit, although for a different purpose. The vapor piping is directed through the flue gas path in the boiler furnace. The temp in this field is between 1 typically,300 and 1,600 °C (2,372 and 2,912 °F). Some superheaters are radiant type; that is, they absorb heat by radiation. Others are convection type, absorbing temperature from a fluid. 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 temperatures of the vapor in the superheater goes up, 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 damage to the turbine blading and associated piping.

    Supercritical steam generator

    Boiler for a charged power herb.
    Main article: Supercritical steam generator
    Supercritical steam generators are used for the production of energy frequently. They operate at supercritical pressure. As opposed to a “subcritical boiler”, a supercritical steam generator operates at such a high pressure (over 3,200 psi or 22 MPa) that the physical turbulence that characterizes boiling ceases that occurs; the fluid is neither water nor gas but a super-critical liquid. There is no era of vapor bubbles within water, because the pressure is above the critical pressure point of which vapor bubbles can develop. As the fluid expands through the turbine stages, its thermodynamic condition drops below the critical point as it can work turning the turbine which changes the power generator from which power is eventually extracted. The liquid at that point may be considered a mix of steam and liquid droplets as it passes into the condenser. This leads to somewhat less energy use and therefore less greenhouse gas production. The term “boiler” shouldn’t 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 upper limit of steam pressure, the operating pressuretrol, which controls when the boiler fires to maintain pressure, and for boilers outfitted with a modulating burner, a modulating pressuretrol which handles the quantity of fire.
    Safety valve: It is utilized to alleviate pressure and prevent possible explosion of the boiler.
    Water level indicators: They show the operator the level of fluid in the boiler, known as a view cup also, water gauge or water column.
    Bottom level blowdown valves: They provide a way for removing solid particulates that condense and rest on underneath of the boiler. As the name implies, this valve is located straight on underneath of the boiler usually, and is sometimes opened up to use the pressure in the boiler to push these particulates out.
    Constant blowdown valve: This enables a small level of water to flee continuously. Its purpose is to avoid water in the boiler becoming saturated with dissolved salts. Saturation would lead to foaming and cause drinking water droplets to be transported over with the vapor – a condition known as priming. Blowdown is also often used to monitor the chemistry of the boiler drinking water.
    Trycock: a type of valve that is often use to manually check a liquid level in a tank. Most commonly entirely on a drinking water boiler.
    Flash tank: High-pressure blowdown enters this vessel where the vapor can ‘flash’ safely and be used in a low-pressure system or be vented to atmosphere while the ambient pressure blowdown moves to drain.
    Automatic blowdown/constant heat recovery system: This technique allows the boiler to blowdown only when makeup water is moving to the boiler, thereby transferring the utmost amount of heat possible from the blowdown to the makeup water. No flash tank is generally needed as the blowdown discharged is near to the temperatures of the makeup water.
    Hand openings: These are metal plates installed in openings in “header” to permit for inspections & installing tubes and inspection of internal surfaces.
    Steam drum internals, a series of display, scrubber & cans (cyclone separators).
    Low-water cutoff: It is a mechanical means (usually a float change) that is used to turn from the burner or shut down energy to the boiler to prevent it from running once the water moves below a certain point. If a boiler is “dry-fired” (burnt without water in it) it can cause rupture or catastrophic failure.
    Surface blowdown range: It provides a way for removing foam or other lightweight non-condensible substances that have a tendency to float together with water inside the boiler.
    Circulating pump: It is made to circulate drinking water back again to the boiler after they have expelled a few of its heat.
    Feedwater check valve or clack valve: A non-return stop valve in the feedwater collection. This may be fitted to the side of the boiler, just below water level, or to the top of the boiler.[10 –
    Top feed: Within this design for feedwater injection, the water is fed to the top of the boiler. This can reduce boiler fatigue triggered by thermal stress. By spraying the feedwater over a series of trays the water is quickly heated and this can reduce limescale.
    Desuperheater tubes or bundles: Some pipes or bundles of pipes in water drum or the steam drum designed to cool superheated steam, in order to provide auxiliary equipment that will not need, or may be damaged by, dry out steam.
    Chemical substance injection line: A link with add chemicals for controlling feedwater pH.
    Steam accessories
    Main vapor stop valve:
    Steam traps:
    Main steam stop/check valve: It is used on multiple boiler installations.
    Combustion accessories
    Energy oil system:gasoline oil heaters
    Gas system:
    Coal system:
    Soot blower
    Other essential items
    Pressure gauges:
    Feed pumps:
    Fusible plug:
    Inspectors test pressure gauge attachment:
    Name dish:
    Registration plate:(Your comment is awaiting moderation)

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