Boiler

A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.

Applications

Boilers have many applications. They can be used in stationary applications to provide heat, hot water, or steam for domestic use, or in generators and they can be used in mobile applications to provide steam for locomotion in applications such as trains, ships, and boats. Using a boiler is a way to transfer stored energy from the fuel source to the water in the boiler, and then finally to the point of end use.

Turbines all details

Principle of Operation and Design

An ideal steam turbine is considered to be an isentropic process, or constant entropy process, in which the entropy of the steam entering the turbine is equal to the entropy of the steam leaving the turbine. No steam turbine is truly “isentropic”, however, with typical isentropic efficiencies ranging from 20%-90% based on the application of the turbine. The interior of a turbine comprises several sets of blades, or “buckets” as they are more commonly referred to. One set of stationary blades is connected to the casing and one set of rotating blades is connected to the shaft. The sets intermesh with certain minimum clearances, with the size and configuration of sets varying to efficiently exploit the expansion of steam at each stage.

Turbine Efficiency

To maximize turbine efficiency, the steam is expanded, generating work, in a number of stages. These stages are characterized by how the energy is extracted from them and are known as impulse or reaction turbines. Most modern steam turbines are a combination of the reaction and impulse design. Typically, higher pressure sections are impulse type and lower pressure stages are reaction type.

Impulse Turbines

An impulse turbine has fixed nozzles that orient the steam flow into high speed jets. These jets contain significant kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction. A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage.
As the steam flows through the nozzle its pressure falls from steam chest pressure to condenser pressure (or atmosphere pressure). Due to this relatively higher ratio of expansion of steam in the nozzle the steam leaves the nozzle with a very high velocity. The steam leaving the moving blades is a large portion of the maximum velocity of the steam when leaving the nozzle. The loss of energy due to this higher exit velocity is commonly called the "carry over velocity" or "leaving loss".

Reaction Turbines

In the reaction turbine, the rotor blades themselves are arranged to form convergent nozzles. This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator. It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor.

Operation and Maintenance

When warming up a steam turbine for use, the main steam stop valves (after the boiler) have a bypass line to allow superheated steam to slowly bypass the valve and proceed to heat up the lines in the system along with the steam turbine. Also a turning gear is engaged when there is no steam to the turbine to slowly rotate the turbine to ensure even heating to prevent uneven expansion. After first rotating the turbine by the turning gear, allowing time for the rotor to assume a straight plane (no bowing), then the turning gear is disengaged and steam is admitted to the turbine, first to the astern blades then to the ahead blades slowly rotating the turbine at 10 to 15 RPM to slowly warm the turbine.
Problems with turbines are now rare and maintenance requirements are relatively small. Any imbalance of the rotor can lead to vibration, which in extreme cases can lead to a blade letting go and punching straight through the casing. It is, however, essential that the turbine be turned with dry steam. If water gets into the steam and is blasted onto the blades (moisture carryover) rapid impingement and erosion of the blades can occur, possibly leading to imbalance and catastrophic failure. Also, water entering the blades will likely result in the destruction of the thrust bearing for the turbine shaft. To prevent this, along with controls and baffles in the boilers to ensure high quality steam, condensate drains are installed in the steam piping leading to the turbine.

Speed regulation

The control of a turbine with a governor is essential, as turbines need to be run up slowly, to prevent damage while some applications (such as the generation of alternating current electricity) require precise speed control. Uncontrolled acceleration of the turbine rotor can lead to an overspeed trip, which causes the nozzle valves that control the flow of steam to the turbine to close. If this fails then the turbine may continue accelerating until it breaks apart, often spectacularly. Turbines are expensive to make, requiring precision manufacture and special quality materials.

Direct drive

Electrical power stations use large steam turbines driving electric generators to produce most (about 80%) of the world's electricity. Most of these centralised stations are of two types: fossil fuel power plants and nuclear power plants. The turbines used for electric power generation are most often directly coupled to their generators. As the generators must rotate at constant synchronous speeds according to the frequency of the electric power system, the most common speeds are 3000 r/min for 50 Hz systems, and 3600 r/min for 60 Hz systems. In installations with high steam output, as may be found in nuclear power stations, the generator sets may be arranged to operate at half these speeds, but with four-pole generators.

Steam turbine types

Steam turbines are made in a variety of sizes ranging from small 1 hp (0.75 kW) units (rare) used as mechanical drives for pumps, compressors and other shaft driven equipment, to 2,000,000 hp (1,500,000 kW) turbines used to generate electricity. There are several classifications for modern steam turbines.

Steam Supply and Exhaust Conditions

These types include condensing, noncondensing, reheat, extraction and induction.
Noncondensing or backpressure turbines are most widely used for process steam applications. The exhaust pressure is controlled by a regulating valve to suit the needs of the process steam pressure. These are commonly found at refineries, district heating units, pulp and paper plants, and desalination facilities where large amounts of low pressure process steam are available.
Condensing turbines are most commonly found in electrical power plants. These turbines exhaust steam in a partially condensed state, typically of a quality near 90%, at a pressure well below atmospheric to a condenser.
Reheat turbines are also used almost exclusively in electrical power plants. In a reheat turbine, steam flow exits from a high pressure section of the turbine and is returned to the boiler where additional superheat is added. The steam then goes back into an intermediate pressure section of the turbine and continues its expansion.
Extracting type turbines are common in all applications. In an extracting type turbine, steam is released from various stages of the turbine, and used for industrial process needs or sent to boiler feedwater heaters to improve overall cycle efficiency. Extraction flows may be controlled with a valve, or left uncontrolled.
Induction turbines introduce low pressure steam at an intermediate stage to produce additional power.

Casing or Shaft Arrangements

These arrangements include single casing, tandem compound and cross compound turbines. Single casing units are the most basic style where a single casing and shaft are coupled to a generator. Tandem compound are used where two or more casings are directly coupled together to drive a single generator. A cross compound turbine arrangement features two or more shafts not in line driving two or more generators that often operate at different speeds. A cross compound turbine is typically used for many large applications

Steam turbine history

The first device that may be classified as a reaction steam turbine was little more than a toy, the classic Aeolipile, described in the 1st century by Hero of Alexandria in Roman Egypt.More than a thousand years later, the first impact steam turbine with practical applications was invented in 1551 by Taqi al-Din in Ottoman Egypt, who described it as a prime mover for rotating a spit. Similar smoke jacks were later described by John Wilkins in 1648 and Samuel Pepys in 1660. Another steam turbine device was created by Italian Giovanni Branca in 1629.
The modern steam turbine was invented in 1884 by the Englishman Sir Charles Parsons, whose first model was connected to a dynamo that generated 7.5 kW of electricity.After the invention of Parson's steam turbine, which made cheap and plentiful electricity possible and revolutionised marine transport and naval warfare, the world would never be the same again.His patent was licensed and the turbine scaled-up shortly after by an American, George Westinghouse. A number of other variations of turbines have been developed that work effectively with steam. The de Laval turbine (invented by Gustaf de Laval) accelerated the steam to full speed before running it against a turbine blade. This was good, because the turbine is simpler, less expensive and does not need to be pressure-proof. It can operate with any pressure of steam. It is also, however, considerably less efficient. The Parson's turbine also turned out to be relatively easy to scale-up. Parsons had the satisfaction of seeing his invention adopted for all major world power stations. The size of his generators had increased from his first 7.5 kW set up to units of 50,000 kW capacity. He knew that the total output from turbo-generators constructed by his firm C. A. Parsons and Company and by their licensees, for land purposes alone, had exceeded thirty million horse-power.Within Parson's lifetime the generating capacity of a unit was scaled-up by about 10,000 times.

Steam turbine

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884.
It has almost completely replaced the reciprocating piston steam engine (invented by Thomas Newcomen and greatly improved by James Watt) primarily because of its greater thermal efficiency and higher power-to-weight ratio. Because the turbine generates rotary motion, it is particularly suited to be used to drive an electrical generator – about 80% of all electricity generation in the world is by use of steam turbines. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process.

Mitsubishi Heavy Industries

is the primary shipbuilding division Mitsubishi Heavy Industries. It produces primarily specialized commercial vessels, including LNG carriers,　oil tankers, and passenger cruise ships. In addition, it is also a producer of a wide variety of machinery for power plants, energy production and aerospace use.

History
In 1857, at the request of the Tokugawa Shogunate, a group of Dutch engineers began work on the Nagasaki Yotetsusho, a modern, western-style foundry and shipyard near the Dutch settlement of Dejima, at Nagasaki. Renamed Nagasaki Seitetsusho in 1860, it was completed in 1861. Following the Meiji restoration of 1868, the shipyard was placed under control of the new Meiji government, and the first dry dock was completed in 1879.
In 1884 Yataro Iwasaki, the founder of Mitsubishi, leased the Nagasaki Seitetsusho from the government and re-named it the Nagasaki Shipyard & Machinery Works, and started the shipbuilding business on a full scale. He purchased the shipyards outright in 1887. The works was renamed Mitsubishi Shipyard of Mitsubishi Goshi Kaisha in 1893 and additional dry docks were completed by 1896 and 1905.
The company was renamed Mitsubishi Shipbuilding & Engineering Company, Ltd. in 1917 and again renamed as Mitsubishi Heavy Industries in 1934. It became the largest private firm in Japan, manufacturing ships, heavy machinery, airplanes, and railroad cars.
From its inception, the Mitsubishi Nagasaki shipyards were heavily involved in contracts for the Imperial Japanese Navy. The battleship Musashi was completed at Nagasaki in 1942.
Following the dissolution of the zaibatsu after the surrender of Japan at the end of World War II, Mitsubishi Nagasaki came under the aegis of West Japan Heavy-Industries, Ltd., and was again renamed Mitsubishi Shipbuilding & Engineering Co., Ltd. in 1952.
However, in 1964, the three independent companies of Mitsubishi Heavy Industries, decentralized in 1950, were merged again into one company under the name of Mitsubishi Heavy Industries, Ltd., and the works was renamed the Nagasaki Shipyard & Engine Works.

Aerospace systems

As the leading company of the Japan's aerospace industry, Mitsubishi Heavy Industries(MHI) has been engaged in the development and production of a wide variety of aerospace products and thus contributed to the advancement of Japan, a technology-oriented nation, through its cutting-edge technologies.
In the defense sector, MHI has consistently produced jet fighters for Japan Air Self-Defense Force and anti-submarine helicopters for Japan Maritime Self-Defense Force, as well as various other products, such as aero-engines, missiles and torpedoes. The company also plays an important role in the Ballistic Missile Defense System program. In addition, MHI is preparing itself to respond to the needs of the joint operation capabilities.
In the civil aircraft sector, MHI takes charge of the development and manufacture of major airframe components, including fuselage panels for Boeing 777 and composite-material wing boxes for the 787. In the space systems sector, MHI is the producer of the H-2A launch vehicle, Japan's main rocket, and now provides launch services to JAXA for H-2A launches. The company is also involved in the international space station program.
On April 1, 2008, MHI established subsidiary Mitsubishi Aircraft Corporation to develop and produce the MRJ or Mitsubishi Regional Jet, a 70 to 90 passenger regional airliner. MHI is the plurality shareholder of the new company, with Toyota Motor Corporation owning 10%.

Nuclear energy systems

The nuclear business of MHI operates facilities Kobe,Yokohama, Kanagawa,Takasago, Hyogo. It also operates a nuclear fuel manufacturing plant in Tōkai, Ibaraki which processes 440 Metric tons of Uranium per year.
MHI has also developed the Mitsubishi APWR, which, as of July 2007, has been selected for use in two sites in Japan and the United States. MHI has also signed a memorandum of understanding with Areva for the establishment of a joint venture for their next reactor design.
MHI has also been selected as the core company to develop a new generation of Fast Breeder Reactors (FBR) by the Japanese government.After that announcement was made, MHI established a new company, Mitsubishi FBR Systems, Inc. (MFBR) specifically for the development and realization for FBR technology, starting what is likely to be the most aggressive corporate venture into FBR and Generation IV reactor technology.

Fuji Heavy Industries

FHI, is a Japanese company which traces its origins to the Nakajima Aircraft Company (est. 1917), which was the leader in aircraft manufacture for the Japanese military during WWII. At the end of World War II, Nakajima was broken up by the Allied Occupation government, and by 1950 part of the separated operation was already known as Fuji Heavy Industries LTD.
FHI (Reorganized) was established on July 15, 1953 when five Japanese companies, known as Fuji Kogyo, Fuji Jidosha Kogyo, Omiya Fuji Kogyo, Utsunomiya Sharyo and Tokyo Fuji Sangyo, joined to form one of Japan's largest manufacturers of transportation equipment. Currently, FHI employs more than 15,000 people worldwide, operates nine manufacturing plants and sells products in 100 countries. It currently makes Subaru brand cars, and its aerospace division makes parts for Boeing, helicopters for the Japanese Self Defense Force, Raytheon Hawker, and Eclipse Aviation business jets.
In the United States, Fuji Heavy Industries owns Subaru of America, Inc., Subaru Research & Development, Inc., and Subaru of Indiana Automotive, Inc. In 2003, the company adopted the logo of its Subaru division as its worldwide corporate symbol.

What Does Heavy Industry Mean?

What Does Heavy Industry Mean?Relates to a type of business that typically carries a high capital cost (capital-intensive), high barriers to entry and low transportability. The term "heavy" refers to the fact that the items produced by "heavy industry" used to be products such as iron, coal, oil, ships, etc. Today the reference also refers industries that cause disruption to the environment in the form of pollution, deforestation, etc.

Heavy industry in firm names

Many conglomerates in Japan (keiretsu) and South Korea (chaebol), call divisions or companies responsible for capital-intensive manufacturing (shipbuilding, mining, industrial machinery) their "heavy industry" group. All industries have heavy machinery.

Heavy industry in law and government

Heavy industry is often defined by governments and planners in terms of its impacts on the environment. These definitions concentrate on the seriousness of any capital investment required to begin production or of the ecological effect of its associated resource gathering practices and by-products. In these senses, the semiconductor industry is regarded as "heavier" than the consumer electronics industry even though microchips are much more expensive by weight than the products they control.
Heavy industry is also sometimes a special designation in local zoning laws.
Many pollution control laws are based on heavy industry, since heavy industry is usually blamed for pollution more than any other economic activity, rightly or not.

Heavy industry

Heavy industry does not have a single fixed meaning as compared to light industry. It can mean production of products which are either heavy in weight or in the processes leading to their production. In general, it is a popular term used within the name of many Japanese and Korean firms, meaning 'construction' for big projects. Example projects include the construction of large buildings, chemical plants, the H-IIA rocket and also includes the production of construction equipment such as cranes and bulldozers. Alternatively, heavy industry projects can be generalized as more capital intensive or as requiring greater or more advanced resources, facilities or management.

Personal Info

Hi,

This is Rao Tanvir Ahmed Rajpot.

And i m student of BSCS.I am 24 years old.il like to play kricker as allrounder.

Thanks