Liquefied petroleum gas or liquid petroleum gas (LPG or LP gas), also referred to as simply propane or butane, are flammable mixtures of hydrocarbon gases used as fuel in heating appliances, cooking equipment, and vehicles.
Propane is a three-carbon alkane with the molecular formula C3H8. It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel. Propane is one of a group of liquefied petroleum gases (LP gases). The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof.
Butane is an organic compound with the formula C4H10 that is an alkane with four carbon atoms. Butane is a gas at room temperature and atmospheric pressure. The term may refer to either of two structural isomers, n-butane or isobutane (also called "methylpropane"), or to a mixture of these isomers. In the IUPAC nomenclature, however, "butane" refers only to the n-butane isomer (which is the isomer with the unbranched structure). Butanes are highly flammable, colorless, easily liquefied gases that quickly vaporize at room temperature. The name butane comes from the roots but- (from butyric acid, named after the Greek word for butter) and -ane. It was discovered by the chemist Edward Frankland in 1849.
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons from which one hydrogen atom has been removed are functional groups called hydrocarbyls. Because carbon has 4 electrons in its outermost shell carbon has exactly four bonds to make, and is only stable if all 4 of these bonds are used.
It is increasingly used as an aerosol propellantand a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. When specifically used as a vehicle fuel it is often referred to as autogas.
A refrigerant is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle. In most cycles it undergoes phase transitions from a liquid to a gas and back again. Many working fluids have been used for such purposes. Fluorocarbons, especially chlorofluorocarbons, became commonplace in the 20th century, but they are being phased out because of their ozone depletion effects. Other common refrigerants used in various applications are ammonia, sulfur dioxide, and non-halogenated hydrocarbons such as propane.
Chlorofluorocarbons (CFCs) are fully halogenated paraffin hydrocarbons that contain only carbon (C), chlorine (Cl), and fluorine (F), produced as volatile derivative of methane, ethane, and propane. They are also commonly known by the DuPont brand name Freon. The most common representative is dichlorodifluoromethane. Many CFCs have been widely used as refrigerants, propellants, and solvents. Because CFCs contribute to ozone depletion in the upper atmosphere, the manufacture of such compounds has been phased out under the Montreal Protocol, and they are being replaced with other products such as hydrofluorocarbons (HFCs) and R-134a.
The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 15 to 35 kilometers (9.3 to 21.7 mi) above Earth, although its thickness varies seasonally and geographically.
Varieties of LPG bought and sold include mixes that are mostly propane (C
8), mostly butane (C
10) and, most commonly, mixes including both propane and butane. In the northern hemisphere winter, the mixes contain more propane, while in summer, they contain more butane. In the United States, mainly two grades of LPG are sold: commercial propane and HD-5. These specifications are published by the Gas Processors Association (GPA) and the American Society of Testing and Materials (ASTM). Propane/butane blends are also listed in these specifications.
The United States of America (USA), commonly known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.
Propylene, butylenes and various other hydrocarbons are usually also present in small concentrations. HD-5 limits the amount of propylene that can be placed in LPG to 5%, and is utilized as an autogas specification. A powerful odorant, ethanethiol, is added so that leaks can be detected easily. The internationally recognized European Standard is EN 589. In the United States, tetrahydrothiophene (thiophane) or amyl mercaptan are also approved odorants,although neither is currently being utilized.
Ethanethiol, commonly known as ethyl mercaptan, is a clear liquid with a distinct odor. It is an organosulfur compound with the formula CH3CH2SH. Abbreviated EtSH, it consists of an ethyl group (Et), CH3CH2, attached to a thiol group, SH. Its structure parallels that of ethanol, but with sulfur in place of oxygen. The odor of EtSH is infamous. Ethanethiol is more volatile than ethanol due to a diminished ability to engage in hydrogen bonding. Ethanethiol is toxic. It occurs naturally as a minor component of petroleum, and may be added to otherwise odorless gaseous products such as liquefied petroleum gas (LPG) to help warn of gas leaks. At these concentrations, ethanethiol is not harmful.
Tetrahydrothiophene is an organosulfur compound with the formula (CH2)4S. It contains a five-membered ring consisting of four carbon atoms and a sulfur atom. It is the saturated analog of thiophene. It is a volatile, colorless liquid with an intensely unpleasant odor. It is also known as thiophane, thiolane, or THT.
Thiol is an organosulfur compound of the form R-SH, where R represents an alkyl or other organic substituent. Thiols are the sulfur analogue of alcohols, and the word is a portmanteau of "thion" + "alcohol," with the first word deriving from Greek θεῖον (theion) = "sulfur". The –SH functional group itself is referred to as either a thiol group or a sulfhydryl group.
LPG is prepared by refining petroleum or "wet" natural gas, and is almost entirely derived from fossil fuel sources, being manufactured during the refining of petroleum (crude oil), or extracted from petroleum or natural gas streams as they emerge from the ground. It was first produced in 1910 by Dr. Walter Snelling, and the first commercial products appeared in 1912. It currently provides about 3% of all energy consumed, and burns relatively cleanly with no soot and very few sulfur emissions. As it is a gas, it does not pose ground or water pollution hazards, but it can cause air pollution. LPG has a typical specific calorific value of 46.1 MJ/kg compared with 42.5 MJ/kg for fuel oil and 43.5 MJ/kg for premium grade petrol (gasoline). However, its energy density per volume unit of 26 MJ/L is lower than either that of petrol or fuel oil, as its relative density is lower (about 0.5–0.58 kg/L, compared to 0.71–0.77 kg/L for gasoline).
Petroleum is a naturally occurring, yellowish-black liquid found in geological formations beneath the Earth's surface. It is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation, i.e. separation of a liquid mixture into fractions differing in boiling point by means of distillation, typically using a fractionating column.
Natural gas, also called "Fossil Gas" is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium. It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years. The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas.
A fossil fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms, containing energy originating in ancient photosynthesis. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years. Fossil fuels contain high percentages of carbon and include petroleum, coal, and natural gas. Other commonly used derivatives include kerosene and propane. Fossil fuels range from volatile materials with low carbon to hydrogen ratios like methane, to liquids like petroleum, to nonvolatile materials composed of almost pure carbon, like anthracite coal. Methane can be found in hydrocarbon fields either alone, associated with oil, or in the form of methane clathrates.
As its boiling point is below room temperature, LPG will evaporate quickly at normal temperatures and pressures and is usually supplied in pressurised steel vessels. They are typically filled to 80–85% of their capacity to allow for thermal expansion of the contained liquid. The ratio between the volumes of the vaporized gas and the liquefied gas varies depending on composition, pressure, and temperature, but is typically around 250:1. The pressure at which LPG becomes liquid, called its vapour pressure, likewise varies depending on composition and temperature; for example, it is approximately 220 kilopascals (32 psi) for pure butane at 20 °C (68 °F), and approximately 2,200 kilopascals (320 psi) for pure propane at 55 °C (131 °F). LPG is heavier than air, unlike natural gas, and thus will flow along floors and tend to settle in low spots, such as basements. There are two main dangers from this. The first is a possible explosion if the mixture of LPG and air is within the explosive limits and there is an ignition source. The second is suffocation due to LPG displacing air, causing a decrease in oxygen concentration.
Temperature is a physical quantity expressing hot and cold. It is measured with a thermometer calibrated in one or more temperature scales. The most commonly used scales are the Celsius scale, Fahrenheit scale, and Kelvin scale. The kelvin is the unit of temperature in the International System of Units (SI), in which temperature is one of the seven fundamental base quantities. The Kelvin scale is widely used in science and technology.
Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the ambient pressure.
Steel is an alloy of iron and carbon, and sometimes other elements. Because of its high tensile strength and low cost, it is a major component used in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.
LPG has a very wide variety of uses, mainly used for cylinders across many different markets as an efficient fuel container in the agricultural, recreation, hospitality, industrial, construction, sailing and fishing sectors. It can serve as fuel for cooking, central heating and to water heating and is a particularly cost-effective and efficient way to heat off-grid homes.
LPG is used for cooking in many countries for economic reasons, for convenience or because it is the preferred fuel source.
In India, nearly 8.9 million tons LPG was consumed during April to September 2016 (six months) in domestic sector mainly for cooking. The number of domestic connections are 215 million (i.e. one connection for every six people) with a circulation of more than 350 million LPG cylinders.Most of the LPG requirement is imported. Piped city gas supply in India is not yet developed on major scale. LPG is subsidised by the government in India for domestic users. Increase in LPG prices has been a politically sensitive matter in India as it potentially affects the middle class voting pattern.
LPG was once a standard cooking fuel in Hong Kong; however, the continued expansion of town gas to newer buildings has reduced LPG usage to less than 24% of residential units. However, other than electric, induction or infrared stove; LPG-fueled stove is the only type available in most suburban villages and many public housing estates.
LPG is the most common cooking fuel in Brazilian urban areas, being used in virtually all households, with the exception of the cities of Rio de Janeiro and São Paulo, which have a natural gas pipeline infrastructure. Since 2001, poor families receive a government grant ("Vale Gás") used exclusively for the acquisition of LPG. Since 2003, this grant is part of the government main social welfare program ("Bolsa Família"). Also, since 2005 the national oil company Petrobras differentiates between LPG destined for cooking and LPG destined for other uses, practicing a lower price for the former. This is a result of a directive from Brazilian federal government, but its demise is currently being debated.
LPG is commonly used in North America for domestic cooking and outdoor grilling.
Predominantly in Europe and rural parts of many countries, LPG can provide an alternative to electric heating, heating oil, or kerosene. LPG is most often used in areas that do not have direct access to piped natural gas.
LPG can be used as a power source for combined heat and power technologies (CHP). CHP is the process of generating both electrical power and useful heat from a single fuel source. This technology has allowed LPG to be used not just as fuel for heating and cooking, but also for decentralized generation of electricity.
LPG can be stored in a variety of manners. LPG, as with other fossil fuels, can be combined with renewable power sources to provide greater reliability while still achieving some reduction in CO2 emissions. However, as opposed to wind and solar renewable energy sources, LPG can be used as a standalone energy source without the prohibitive expense of electrical energy storage. In many climates renewable sources such as solar and wind power would still require the construction, installation and maintenance of reliable baseload power sources such as LPG fueled generation to provide electrical power during the entire year. 100% wind/solar is possible, the caveat being that even in 2018 the expense of the additional generation capacity necessary to charge batteries, plus the cost of battery electrical storage, still makes this option economically feasible in only a minority of situations.
When LPG is used to fuel internal combustion engines, it is often referred to as autogas or auto propane. In some countries, it has been used since the 1940s as a petrol alternative for spark ignition engines. In some countries, there are additives in the liquid that extend engine life and the ratio of butane to propane is kept quite precise in fuel LPG. Two recent studies have examined LPG-fuel-oil fuel mixes and found that smoke emissions and fuel consumption are reduced but hydrocarbon emissions are increased.The studies were split on CO emissions, with one finding significant increases, and the other finding slight increases at low engine load but a considerable decrease at high engine load. Its advantage is that it is non-toxic, non-corrosive and free of tetraethyllead or any additives, and has a high octane rating (102–108 RON depending on local specifications). It burns more cleanly than petrol or fuel-oil and is especially free of the particulates present in the latter.
LPG has a lower energy density per liter than either petrol or fuel-oil, so the equivalent fuel consumption is higher. Many governments impose less tax on LPG than on petrol or fuel-oil, which helps offset the greater consumption of LPG than of petrol or fuel-oil. However, in many European countries this tax break is often compensated by a much higher annual tax on cars using LPG than on cars using petrol or fuel-oil. Propane is the third most widely used motor fuel in the world. 2013 estimates are that over 24.9 million vehicles are fueled by propane gas worldwide. Over 25 million tonnes (over 9 billion US gallons) are used annually as a vehicle fuel.
Not all automobile engines are suitable for use with LPG as a fuel. LPG provides less upper cylinder lubrication than petrol or diesel, so LPG-fueled engines are more prone to valve wear if they are not suitably modified. Many modern common rail diesel engines respond well to LPG use as a supplementary fuel. This is where LPG is used as fuel as well as diesel. Systems are now available that integrate with OEM engine management systems.
LPG can be converted into alkylate which is a premium gasoline blending stock because it has exceptional anti-knock properties and gives clean burning.
LPG is instrumental in providing off-the-grid refrigeration, usually by means of a gas absorption refrigerator.
Blended of pure, dry propane (refrigerant designator R-290) and isobutane (R-600a) the blend "R-290a" has negligible ozone depletion potential and very low global warming potential and can serve as a functional replacement for R-12, R-22, R-134a and other chlorofluorocarbon or hydrofluorocarbon refrigerants in conventional stationary refrigeration and air conditioning systems.
Such substitution is widely prohibited or discouraged in motor vehicle air conditioning systems, on the grounds that using flammable hydrocarbons in systems originally designed to carry non-flammable refrigerant presents a significant risk of fire or explosion.
Vendors and advocates of hydrocarbon refrigerants argue against such bans on the grounds that there have been very few such incidents relative to the number of vehicle air conditioning systems filled with hydrocarbons.One particular test, conducted by a professor at the University of New South Wales, unintentionally tested the worst-case scenario of a sudden and complete refrigerant expulsion into the passenger compartment followed by subsequent ignition. He and several others in the car sustained minor burns to their face, ears, and hands, and several observers received lacerations from the burst glass of the front passenger window. No one was seriously injured.
Global LPG production reached over 292 million metric tons/yr in 2015, while global LPG consumption to over 284 mn t/yr.62% of LPG is extracted from natural gas while the rest is produced by the petrochemical refineries from crude oil. 44% of global consumption is in the domestic sector. The USA is the leading producer and exporter of LPG.
Because of the natural gas and the oil-refining industry, Europe is almost self-sufficient in LPG. Europe's security of supply is further safeguarded by:
According to 2010–12 estimates, proven world reserves of natural gas, from which most LPG is derived, stand at 300 trillion cubic meters (10,600 trillion cubic feet). Added to the LPG derived from cracking crude oil, this amounts to a major energy source that is virtually untapped and has massive potential. Production continues to grow at an average annual rate of 2.2%, virtually assuring that there is no risk of demand outstripping supply in the foreseeable future.[ citation needed ]
LPG is composed mainly of propane and butane, while natural gas is composed of the lighter methane and ethane. LPG, vaporised and at atmospheric pressure, has a higher calorific value (46 MJ/m3 equivalent to 12.8 kWh/m3) than natural gas (methane) (38 MJ/m3 equivalent to 10.6 kWh/m3), which means that LPG cannot simply be substituted for natural gas. In order to allow the use of the same burner controls and to provide for similar combustion characteristics, LPG can be mixed with air to produce a synthetic natural gas (SNG) that can be easily substituted. LPG/air mixing ratios average 60/40, though this is widely variable based on the gases making up the LPG. The method for determining the mixing ratios is by calculating the Wobbe index of the mix. Gases having the same Wobbe index are held to be interchangeable.
LPG-based SNG is used in emergency backup systems for many public, industrial and military installations, and many utilities use LPG peak shaving plants in times of high demand to make up shortages in natural gas supplied to their distributions systems. LPG-SNG installations are also used during initial gas system introductions, when the distribution infrastructure is in place before gas supplies can be connected. Developing markets in India and China (among others) use LPG-SNG systems to build up customer bases prior to expanding existing natural gas systems.
LPG-based SNG or natural gas with localized storage and piping distribution network to the house holds for catering to each cluster of 5000 domestic consumers can be planned under initial phase of city gas network system. This would eliminate the last mile LPG cylinders road transport which is a cause of traffic and safety hurdles in Indian cities. These localized natural gas networks are successfully operating in Japan with feasibility to get connected to wider networks in both villages and cities.
Commercially available LPG is currently derived mainly from fossil fuels. Burning LPG releases carbon dioxide, a greenhouse gas. The reaction also produces some carbon monoxide. LPG does, however, release less CO
2 per unit of energy than does coal or oil. It emits 81% of the CO
2 per kWh produced by oil, 70% of that of coal, and less than 50% of that emitted by coal-generated electricity distributed via the grid. Being a mix of propane and butane, LPG emits less carbon per joule than butane but more carbon per joule than propane.
LPG burns more cleanly than higher molecular weight hydrocarbons because it releases fewer particulates.
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In a refinery or gas plant, LPG must be stored in pressure vessels. These containers are either cylindrical and horizontal or spherical. Typically, these vessels are designed and manufactured according to some code. In the United States, this code is governed by the American Society of Mechanical Engineers (ASME).
LPG containers have pressure relief valves, such that when subjected to exterior heating sources, they will vent LPGs to the atmosphere or a flare stack.
If a tank is subjected to a fire of sufficient duration and intensity, it can undergo a boiling liquid expanding vapor explosion (BLEVE). This is typically a concern for large refineries and petrochemical plants that maintain very large containers. In general, tanks are designed so that the product will vent faster than pressure can build to dangerous levels.
One remedy that is utilized in industrial settings is to equip such containers with a measure to provide a fire-resistance rating. Large, spherical LPG containers may have up to a 15 cm steel wall thickness. They are equipped with an approved pressure relief valve. A large fire in the vicinity of the vessel will increase its temperature and pressure. The relief valve on the top is designed to vent off excess pressure in order to prevent the rupture of the container itself. Given a fire of sufficient duration and intensity, the pressure being generated by the boiling and expanding gas can exceed the ability of the valve to vent the excess. If that occurs, an overexposed container may rupture violently, launching pieces at high velocity, while the released products can ignite as well, potentially causing catastrophic damage to anything nearby, including other containers.
People can be exposed to LPG in the workplace by breathing it in, skin contact, and eye contact. The Occupational Safety and Health Administration (OSHA) has set the legal limit (Permissible exposure limit) for LPG exposure in the workplace as 1000 ppm (1800 mg/m3) over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 1000 ppm (1800 mg/m3) over an 8-hour workday. At levels of 2000 ppm, 10% of the lower explosive limit, LPG is considered immediately dangerous to life and health (due solely to safety considerations pertaining to risk of explosion).
A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value.
Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields. Some gas species within the raw natural gas will condense to a liquid state if the temperature is reduced to below the hydrocarbon dew point temperature at a set pressure.
Alternative fuels, known as non-conventional and advanced fuels, are any materials or substances that can be used as fuels, other than conventional fuels like; fossil fuels, as well as nuclear materials such as uranium and thorium, as well as artificial radioisotope fuels that are made in nuclear reactors.
Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable instead of the fluid. Most liquid fuels in widespread use are derived from fossil fuels; however, there are several types, such as hydrogen fuel, ethanol, and biodiesel, which are also categorized as a liquid fuel. Many liquid fuels play a primary role in transportation and the economy.
Cryogenic fuels are fuels that require storage at extremely low temperatures in order to maintain them in a liquid state. These fuels are used in machinery that operates in space because ordinary fuel cannot be used there, due to absence of an environment that supports combustion and space is a vacuum. Cryogenic fuels most often constitute liquefied gases such as liquid hydrogen.
Liquefied natural gas (LNG) is natural gas (predominantly methane, CH4, with some mixture of ethane C2H6) that has been cooled down to liquid form for ease and safety of non-pressurized storage or transport. It takes up about 1/600th the volume of natural gas in the gaseous state (at standard conditions for temperature and pressure). It is odorless, colorless, non-toxic and non-corrosive. Hazards include flammability after vaporization into a gaseous state, freezing and asphyxia. The liquefaction process involves removal of certain components, such as dust, acid gases, helium, water, and heavy hydrocarbons, which could cause difficulty downstream. The natural gas is then condensed into a liquid at close to atmospheric pressure by cooling it to approximately −162 °C (−260 °F); maximum transport pressure is set at around 25 kPa (4 psi).
Substitute natural gas (SNG), or synthetic natural gas, is a fuel gas that can be produced from fossil fuels such as lignite coal, oil shale, or from biofuels or from renewable electrical energy.
Fuel gas is any one of a number of fuels that under ordinary conditions are gaseous. Many fuel gases are composed of hydrocarbons, hydrogen, carbon monoxide, or mixtures thereof. Such gases are sources of potential heat energy or light energy that can be readily transmitted and distributed through pipes from the point of origin directly to the place of consumption.
The Wobbe Index (WI) or Wobbe number is an indicator of the interchangeability of fuel gases such as natural gas, liquefied petroleum gas (LPG), and town gas and is frequently defined in the specifications of gas supply and transport utilities.
Autogas is the common name for liquefied petroleum gas (LPG) when it is used as a fuel in internal combustion engines in vehicles as well as in stationary applications such as generators. It is a mixture of propane and butane.
Calor Gas is a brand of bottled butane and propane which is available in Britain and Ireland. It comes in cylinders, which have a special gas regulator.
A propane torch is a tool normally used for the application of flame or heat which uses propane, a hydrocarbon gas, for its fuel. Propane is one of a group of by-products of the natural gas and petroleum industries known as liquefied petroleum gas or LPG. Propane and other fuel torches are most commonly used in the manufacturing, construction and metal-working industries.
A bivalent engine is an engine that can use two different types of fuel. Examples are petroleum/CNG and petroleum/LPG engines, which are widely available in the European passenger vehicle aftermarket.
The energy policy of India is largely defined by the country's expanding energy deficit and increased focus on developing alternative sources of energy, particularly nuclear, solar and wind energy. India ranks 81 position in overall energy self-sufficiency at 66% in 2014.
Sustainable automotive air conditioning is the subject of a debate – nicknamed the Cool War – about the next-generation refrigerant in car air conditioning. The Alliance for CO2 Solutions supports the uptake of carbon dioxide (CO2) as a refrigerant in passenger cars, and the chemical industry is developing new chemical blends.
A fuel is any material that can be made to react with other substances so that it releases energy as heat energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy such as nuclear energy.
Compressed natural gas (CNG) carrier ships are designed for transportation of natural gas under high pressure. CNG carrier technology relies on high pressure, typically over 250 bar (2900 psi), to increase the density of the gas, but it is still 2.4 times less than that of LNG (426 kg/m3). CNG carriers may find their place abreast with the well established technology of liquefied natural gas by LNG carriers as it is economical for medium distance marine transport. Most of the energy consumed for the gas pressurisation can be recovered as electricity using turboexpander while delivering CNG to the inland piping network at unloading jetty/harbour. CNG carriers are also alternate solutions to the undersea pipelines as they have less complicated fast loading and unloading features.
A blowtorch, or blowlamp (UK), is a fuel-burning tool used for applying flame and heat to various applications, usually metalworking.