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Steam is
water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , even though it provide ...

water
in the
gas Gas is one of the four fundamental states of matter (the others being solid Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma). The molecules in a solid are closely packed together and c ...

gas
phase. This may occur due to
evaporation File:10. Ладење при испарување.ogv, 280px, Demonstration of evaporative cooling. When the sensor is dipped in ethanol and then taken out to evaporate, the instrument shows progressively lower temperature as the ethanol evapor ...

evaporation
or due to
boiling Boiling is the rapid vaporization Vaporization (or vaporisation) of an element or compound is a phase transition In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds ...
, where heat is applied until water reaches the
enthalpy of vaporization The enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy ( enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas. T ...
. Steam that is saturated or superheated is invisible; however, "steam" often refers to wet steam, the visible
mist Mist is a phenomenon caused by small droplets of water Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and ...

mist
or
aerosol An aerosol (abbreviation of "aero-solution") is a suspension Suspension or suspended may refer to: Science and engineering * Suspension (topology), in mathematics * Suspension (dynamical systems), in mathematics * Suspension of a ring, in mathe ...

aerosol
of water droplets formed as water vapour
condenses Condensation is the change of the physical state of matter from the gas phase In the physical sciences, a phase is a region of space (a thermodynamic system), throughout which all physical properties of a material are essentially uniform. E ...
. Water increases in
volume Volume is a expressing the of enclosed by a . For example, the space that a substance (, , , or ) or occupies or contains. Volume is often quantified numerically using the , the . The volume of a container is generally understood to be the ...

volume
by 1,700 times at
standard temperature and pressure Standard temperature and pressure (STP) are standard Standard may refer to: Flags * Colours, standards and guidons * Standard (flag), a type of flag used for personal identification Norm, convention or requirement * Standard (metrology), a ...
; this change in volume can be converted into
mechanical work In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related entities of energy and force. ...

mechanical work
by
steam engine from Stott Park Bobbin Mill, Cumbria, England A steam engine is a heat engine In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energ ...

steam engine
s such as reciprocating piston type engines and
steam turbine A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do Work (physics), mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Algernon Parsons, Charles Parsons in 188 ...
s, which are a sub-group of steam engines. Piston type steam engines played a central role in the
Industrial Revolution The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe Continental Europe or mainland Europe is the contiguous continent A continent is any of several large landmasse ...
and modern steam turbines are used to generate more than 80% of the world's
electricity Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, motion is the phenomenon in which an object changes its positio ...

electricity
. If liquid water comes in contact with a very hot surface or depressurizes quickly below its
vapor pressure 280px, The ''pistol test tube'' experiment. The tube contains alcohol and is closed with a piece of cork. By heating the alcohol, the vapors fill in the space, increasing the pressure in the tube to the point of the cork popping out. Vapor pre ...

vapor pressure
, it can create a
steam explosion upright=1.5, Littoral explosion at Waikupanaha ocean entry at the big island of Hawaii was caused by the lava entering the ocean ">ocean.html" ;"title="lava entering the ocean">lava entering the ocean A steam explosion is an explosion caused by ...
.


Types of steam and conversions

Steam is traditionally created by heating a boiler via burning coal and other fuels, but it is also possible to create steam with solar energy. Water vapor that includes water droplets is described as wet steam. As wet steam is heated further, the droplets evaporate, and at a high enough temperature (which depends on the pressure) all of the water evaporates and the system is in
vapor–liquid equilibrium In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantit ...
. When steam has reached this equilibrium point, it is referred to as saturated steam.
Superheated steam Superheated steam is steam Steam is water Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids ...
is steam at a temperature higher than its
boiling point The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding enviro ...
for the pressure, which only occurs when all liquid water has evaporated or has been removed from the system.
Steam table Steam is water Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere an ...
s contain thermodynamic data for water/saturated steam and are often used by engineers and scientists in design and operation of equipment where thermodynamic cycles involving steam are used. Additionally, thermodynamic
phase diagram A phase diagram in physical chemistry Physical chemistry is the study of macroscopic The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye, without magnifying optical ins ...

phase diagram
s for water/steam, such as a temperature-entropy diagram or a Mollier diagram shown in this article, may be useful. Steam charts are also used for analysing thermodynamic cycles.


Uses


Agricultural

In
agriculture Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of , whereby farming of species created food that enabled people to live in cities. The began thousands of ...

agriculture
, steam is used for soil sterilization to avoid the use of harmful chemical agents and increase
soil health Soil health is a state of a soil meeting its range of ecosystem functions as appropriate to its environment. In more colloquial terms, the health of soil arises from favorable interactions of all soil components (living and non-living) that belong t ...
.


Chemical

Steam is used in various chemical processes as reactant, especially in the
petrochemical industryThe petrochemical industry is concerned with the production and trade of petrochemicals. A major part is constituted by the plastics (polymer) industry. It directly interfaces with the petroleum industry The petroleum industry, also known as the ...
.
Steam cracking Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons. It is the principal industrial method for producing the lighter alkene , the simplest alkene. In chemistr ...

Steam cracking
of long chain hydrocarbons produces lower molecular weight hydrocarbons for fuel or chemical applications.
Steam reforming Steam reforming or steam methane reforming is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. The main purpose of this technology is hydrogen production. The ...
produces
syngas Syngas, or synthesis gas, is a fuel gas Fuel gas is any one of a number of fuels that under ordinary conditions are gaseous. Many fuel gases are composed of hydrocarbons (such as methane or propane), hydrogen Hydrogen is the chemica ...
or
hydrogen Hydrogen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

hydrogen
.


Domestic

Steam's capacity to transfer heat is also used in the home: for cooking vegetables, steam cleaning of fabric, carpets and flooring, and for heating buildings. In each case, water is heated in a boiler, and the steam carries the energy to a target object. Steam is also used in ironing clothes to add enough humidity with the heat to take wrinkles out and put intentional creases into the clothing.


Electricity generation (and cogeneration)

As of 2000 around 90% of all electricity was generated using steam as the
working fluid For fluid power, a working fluid is a gas or liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force ...
, nearly all by
steam turbine A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do Work (physics), mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Algernon Parsons, Charles Parsons in 188 ...
s. In electric generation, steam is typically condensed at the end of its expansion cycle, and returned to the boiler for re-use. However, in
cogeneration Cogeneration or combined heat and power (CHP) is the use of a heat engine In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, ...

cogeneration
, steam is piped into buildings through a
district heating . District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements such as space heater, s ...

district heating
system to provide heat energy after its use in the electric generation cycle. The world's biggest steam generation system is the New York City steam system, which pumps steam into 100,000 buildings in
Manhattan Manhattan (), known regionally as ''The City'', is the most densely populated and geographically smallest of the of . It is the urban core of the , and coextensive with New York County, one of the of the of . Manhattan serves as the city's ...

Manhattan
from seven cogeneration plants.


Energy storage

In other industrial applications steam is used for
energy storage Energy storage is the capture of energy In physics, energy is the physical quantity, quantitative physical property, property that must be #Energy transfer, transferred to a physical body, body or physical system to perform Work (thermody ...

energy storage
, which is introduced and extracted by heat transfer, usually through pipes. Steam is a capacious reservoir for thermal energy because of water's high
heat of vaporization The enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and ...
.
Fireless steam locomotive
Fireless steam locomotive
s were
steam locomotive A steam locomotive is a rail vehicle A railroad car, railcar (American English, American and Canadian English), railway wagon, railway carriage, railway truck, railwagon, railcarriage or railtruck (British English and International Union ...

steam locomotive
s that operated from a supply of steam stored on board in a large tank resembling a conventional locomotive's boiler. This tank was filled by
process steam A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process A business process, business method or ...
, as is available in many sorts of large factory, such as
paper mill A paper mill is a factory A factory, manufacturing plant or a production plant is an industrial Industrial may also refer to: Industry * Industrial archaeology, the study of the history of the industry * Industrial engineering, engineering ...
s. The locomotive's propulsion used pistons and connecting rods, as for a typical steam locomotive. These locomotives were mostly used in places where there was a risk of fire from a boiler's firebox, but were also used in factories that simply had a plentiful supply of steam to spare.


Mechanical effort

Steam engine from Stott Park Bobbin Mill, Cumbria, England A steam engine is a heat engine In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energ ...

Steam engine
s and
steam turbines A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. The steam turbine is a form of heat ...

steam turbines
use the expansion of steam to drive a
piston A piston is a component of reciprocating engine , internal combustion piston engine. A reciprocating engine, also often known as a piston engine, is typically a heat engine (although there are also pneumatic Pneumatics (from Greek ‘wind, ...

piston
or
turbine A turbine ( or ) (from the Greek , ''tyrbē'', or Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Lat ...

turbine
to perform
mechanical work In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related entities of energy and force. ...
. The ability to return condensed steam as water-liquid to the boiler at high pressure with relatively little expenditure of pumping power is important.
Condensation Condensation is the change of the state of matter In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and Plasma (physics), plasma. ...

Condensation
of steam to water often occurs at the low-pressure end of a steam turbine, since this maximizes the
energy efficiency Energy efficiency may refer to: * Energy efficiency (physics), the ratio between the useful output and input of an energy conversion process ** Electrical efficiency, useful power output per electrical power consumed ** Mechanical efficiency, a rat ...
, but such wet-steam conditions must be limited to avoid excessive turbine blade erosion. Engineers use an idealised
thermodynamic cycle A thermodynamic cycle consists of a linked sequence of thermodynamic processes that involve transfer of heat and work into and out of the system, while varying pressure, temperature, and other state variables within the system, and that eventual ...
, the
Rankine cycle The Rankine cycle is an idealized thermodynamic cycle A thermodynamic cycle consists of a linked sequence of thermodynamic processes that involve transfer of heat and work into and out of the system, while varying pressure, temperature, and othe ...
, to model the behavior of steam engines. Steam turbines are often used in the production of electricity.


Sterilization

An
autoclave An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure/Ambient temperature, temperature. Autoclaves are used in medical applications to perform ...

autoclave
, which uses steam under pressure, is used in microbiology laboratories and similar environments for sterilization. Steam, especially dry (highly superheated) steam, may be used for antimicrobial cleaning even to the levels of sterilization. Steam is a non-toxic antimicrobial agent.


Steam in piping

Steam is used in
piping Within industry, piping is a system of pipes PIPES is the common name for piperazine-N,N′-bis(2-ethanesulfonic acid), and is a frequently used buffering agent in biochemistry. It is an ethanesulfonic acid buffer developed by Good et al. in t ...

piping
for utility lines. It is also used in jacketing and tracing of piping to maintain the uniform temperature in pipelines and vessels.


Wood treatment

Steam is used in the process of wood bending, killing insects and increasing plasticity.


Concrete treatment

Steam is used to accentuate drying especially in prefabricates. Care should be taken since concrete produces heat during hydration and additional heat from the steam could be detrimental to hardening reaction processes of the concrete.


Cleaning

Used in cleaning of fibers and other materials, sometimes in preparation for painting. Steam is also useful in melting hardened grease and oil residues, so it is useful in cleaning kitchen floors and equipment and internal combustion engines and parts. Among the advantages of using steam versus a hot water spray are the facts that steam can operate at higher temperatures and it uses substantially less water per minute.


See also

*
Electrification Electrification is the process of powering by electricity Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, mo ...

Electrification
*
Food steamer A food steamer or steam cooker is a small kitchen appliance used to cook or prepare various foods with steam heat by means of holding the food in a closed vessel reducing steam escape. This manner of cooking is called steaming. History Food ...
or steam cooker *
Geyser A geyser (, ) is a spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric ...

Geyser
—''geothermally-generated steam'' * IAPWS—''an association that maintains international-standard correlations for the
thermodynamic Thermodynamics is a branch of physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related ent ...
properties of steam, including IAPWS-IF97 (for use in industrial simulation and modelling) and IAPWS-95 (a general purpose and scientific correlation).'' *
Industrial Revolution The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe Continental Europe or mainland Europe is the contiguous continent A continent is any of several large landmasse ...
*
Live steam 'live steam' locomotive in gauge, built in 14,000 hours over a period of 15 years. Live steam is steam under pressure, obtained by heating water in a boiler. The steam is used to operate stationary or moving equipment. A live steam machine or ...
*
Mass production Mass production, also known as flow production or continuous production, is the production of substantial amounts of standardized Standardization or standardisation is the process of implementing and developing technical standard A technic ...
*
Nuclear power Nuclear power is the use of s to produce . Nuclear power can be obtained from , and reactions. Presently, the vast majority of electricity from nuclear power is produced by of and in s. Nuclear decay processes are used in niche applicatio ...

Nuclear power
—and
power plant A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation A generation is "all of the people born and living Living or The Living may refer to: ...

power plant
s ''use steam to generate electricity'' *
Oxyhydrogen for producing oxyhydrogen. Oxyhydrogen is a mixture of hydrogen (H2) and oxygen Oxygen is the chemical element with the chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen Group (periodic table), group in t ...
*
Psychrometrics Psychrometrics, psychrometry, and hygrometry are names for the field of engineering concerned with the physical and thermodynamic properties of gas-vapor mixtures. The term comes from the Greek ''psuchron'' (ψυχρόν) meaning "cold" and ''metr ...
—''moist air/vapor mixtures, humidity and air conditioning'' *
Steam locomotive A steam locomotive is a rail vehicle A railroad car, railcar (American English, American and Canadian English), railway wagon, railway carriage, railway truck, railwagon, railcarriage or railtruck (British English and International Union ...

Steam locomotive
*
Steamed Steaming is a method of cooking using steam. This is often done with a food steamer, a kitchen appliance made specifically to cook food with steam, but food can also be steamed in a wok. In the American southwest, steam pits used for cooking have ...
*
Sterilization (microbiology) Sterilization refers to any process that removes, kills, or deactivates all forms of life Life is a characteristic that distinguishes physical entities that have biological processes, such as Cell signaling, signaling and self-sustaining p ...


References


External links


Steam Tables & Charts by National Institute of Standards and Technology, NIST
{{Water
Forms of water {{Portal, Water This category Category, plural categories, may refer to: Philosophy and general uses *Categorization, categories in cognitive science, information science and generally *Category of being *Categories (Aristotle), ''Categories'' ...
Water in gas * Gases