Overblog Suivre ce blog
Editer l'article Administration Créer mon blog
7 novembre 2011 1 07 /11 /novembre /2011 01:43

Natural gas is a gas consisting primarily of methane, typically with 0–20% higher hydrocarbons[1] (primarily ethane). It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock forfertilizers.Sony VAIO VGN-SR41M/P Battery

Most natural gas is created by two mechanisms: biogenic and thermogenic. Biogenic gas is created by methanogenic organisms in marshes, bogs, landfills, and shallow sediments. Deeper in the earth, at greater temperature and pressure, thermogenic gas is created from buried organic material.Sony VAIO VGN-SR41M/S Battery

Before natural gas can be used as a fuel, it must undergo processing to remove almost all materials other than methane. The by-products of that processing include ethane, propane,butanes, pentanes, and higher molecular weight hydrocarbons, elemental sulfur, carbon dioxide,water vapor, and sometimes helium and nitrogen.Sony VAIO VGN-SR49VN/H Battery

Natural gas is often informally referred to as simply gas, especially when compared to other energy sources such as oil or coal.

Natural gas

In the 19th century, natural gas was usually obtained as a byproduct of producing oil, since the small, Sony VAIO VGN-SR51B/P Battery

light gas carbon chains came out of solution as the extracted fluids underwent pressure reduction from the reservoir to the surface, similar to uncapping a bottle of soda pop where the carbon dioxide effervesces. Unwanted natural gas was a disposal problem in the active oil fields. Sony VAIO VGN-SR51B/S Battery

If there was not a market for natural gas near the wellhead it was virtually valueless since it had to be piped to the end user. In the 19th century and early 20th century, such unwanted gas usually was burned off in the oil fields. Today, unwanted gas (or 'stranded' gas without a market)Sony VAIO VGN-SR51MF Battery

associated with oil extraction often is returned to the reservoir with 'injection' wells while awaiting a possible future market or to repressurize the formation, which can enhance extraction rates from other wells. In regions with a high natural gas demand (such as the US), pipelines are constructed when economically feasible to move the gas from the wellsite to the end consumer.Sony VAIO VGN-SR51MF/P Battery

Another solution is to export the natural gas as a liquid. Gas-to-liquids (GTL) is a developing technology that converts stranded natural gas into synthetic gasoline, diesel or jet fuel through the Fischer-Tropsch process developed in WWII Germany. Such fuel can be transported to users through conventional pipelines and tankers. Sony VAIO VGN-SR51MF/S Battery

Proponents claim GTL burns cleaner than comparable petroleum fuels. Most major international oil companies are in an advanced stage of GTL production, with a world-scale (140,000 barrels (22,000 m3) a day) GTL plant in Qatar scheduled to be in production before 2010.Sony VAIO VGN-SR51MF/W Battery

Natural gas can be "associated" (found in oil fields) or "non-associated" (isolated in natural gas fields), and is also found in coal beds (as coalbed methane). It sometimes contains significant amounts of ethane, propane, butane, and pentane—heavier hydrocarbons removed for commercial use prior to the methane being sold as a consumer fuel or chemical plant feedstock.Sony VAIO VGN-SR51MR Battery

Non-hydrocarbons such ascarbon dioxide, nitrogen, helium (rarely), and hydrogen sulfide must be removed also before the natural gas can be transported.

Natural gas is commercially extracted from oil fields and natural gas fields. Gas extracted from oil wells is called casinghead gas or associated gas. Sony VAIO VGN-SR59VG Battery

The natural gas industry is extracting gas from increasingly more challenging resource types: sour gas, tight gas, shale gas, and coalbed methane.

The world's largest proven gas reserves are located in Russia, with 4.757×1013 m³ (1.68×1015 cubic feet). Sony VAIO VGN-SR59VG/H Battery

With the Gazprom company, Russia is frequently the world's largest natural gas extractor. Major proven resources (in billion cubic meters) are world 175,400 (2006), Russia 47,570 (2006), Iran 26,370 (2006), Qatar 25,790 (2007), Saudi Arabia 6,568 (2006) and United Arab Emirates 5,823 (2006).Sony VAIO VGN-SR70B/S Battery

It is estimated that there are about 900 trillion cubic meters of "unconventional" gas such as shale gas, of which 180 trillion may be recoverable.[4]In turn, many studies from MIT, Black & Veatch and the DOE -- see natural gas will account for a larger portion of electricity generation and heat in the future. Sony VAIO VGN-SR72B/P Battery

The world's largest gas field is Qatar's offshore North Field, estimated to have 25 trillion cubic meters[6] (9.0×1014cubic feet) of gas in place—enough to last more than 420 years at optimum extraction levels. The second largest natural gas field is the South Pars Gas Field in Iranian waters in the Persian Gulf. Sony VAIO VGN-SR72B/S Battery

Located next to Qatar's North Field, it has an estimated reserve of 8 to 14 trillion cubic meters[7] (2.8×1014 to 5.0×1014 cubic feet) of gas.

Because natural gas is not a pure product, as the reservoir pressure drops when non-associated gas is extracted from a field under supercritical(pressure/temperature) conditions, Sony VAIO VGN-SR73JB/S Battery

the higher molecular weight components may partially condense upon isothermic depressurizing—an effect called retrograde condensation. The liquid thus formed may get trapped as the pores of the gas reservoir get deposited. Sony VAIO VGN-SR74FB/S Battery

One method to deal with this problem is to re-inject dried gas free of condensate to maintain the underground pressure and to allow re-evaporation and extraction of condensates. More frequently, the liquid condenses at the surface, and one of the tasks of the gas plant to collect this condensate. Sony VAIO VGN-SR90FS Battery

The resulting liquid is called natural gas liquid (NGL) and has commercial value.

Town gas

Town gas is a synthetically produced mixture of methane and other gases, mainly the highly toxic carbon monoxide, that can be used in a similar way to natural gas and can be produced by treating coal chemically. Sony VAIO VGN-SR90NS Battery

This is a historical technology, still used as 'best solution' in some local circumstances, although coal gasification is not usually economic at current gas prices. However, depending upon infrastructure considerations, it remains a future possibility.

Most town "gashouses" located in the eastern US in the late 19th and early 20th centuries were simple by-product coke ovens which heated bituminous coal in air-tight chambers. Sony VAIO VGN-SR90S Battery

The gas driven off from the coal was collected and distributed through networks of pipes to residences and other buildings where it was used for cooking and lighting. (Gas heating did not come into widespread use until the last half of the 20th century.) Sony VAIO VGN-SR90US Battery

The coal tar (or asphalt) that collected in the bottoms of the gashouse ovens was often used for roofing and other water-proofing purposes, and when mixed with sand and gravel was used for paving streets.

Biogas

When methane-rich gases are produced by the anaerobic decay of non-fossil organic matter (biomass), these are referred to as biogas (or natural biogas). Sony VAIO VGN-SR91NS Battery

Sources of biogas include swamps, marshes, and landfills (see landfill gas), as well as sewage sludge and manure[8] by way of anaerobic digesters, in addition to enteric fermentation particularly in cattle.

Methanogenic archaea are responsible for all biological sources of methane, some in symbiotic relationships with other life forms, including termites, ruminants, and cultivated crops. Sony VAIO VGN-SR91PS Battery

Methane released directly into the atmosphere would be considered a pollutant. However, methane in the atmosphere is oxidized, producing carbon dioxide and water. Methane in the atmosphere has a half life of seven years, meaning that if a tonne of methane were emitted today, 500 kilograms would have broken down to carbon dioxide and water after seven years.Sony VAIO VGN-SR91S Battery

Other sources of methane, the principal component of natural gas, include landfill gas, biogas and methane hydrate. Biogas, and especially landfill gas, are already used in some areas, but their use could be greatly expanded. Landfill gas is a type of biogas, but biogas usually refers to gas produced from organic material that has not been mixed with other waste.Sony VAIO VGN-SR91US Battery

Landfill gas is created from the decomposition of waste in landfills. If the gas is not removed, the pressure may get so high that it works its way to the surface, causing damage to the landfill structure, unpleasant odor, vegetation die-off and an explosion hazard.Sony VAIO VGN-SR92NS Battery

The gas can be vented to the atmosphere, flared or burned to produce electricity or heat. Experimental systems were being proposed for use in parts Hertfordshire, UK andLyon in France.

Once water vapor is removed, about half of landfill gas is methane. Almost all of the rest is carbon dioxide, but there are also small amounts of nitrogen, oxygen and hydrogen. Sony VAIO VGN-SR92PS Battery

There are usually trace amounts of hydrogen sulfide and siloxanes, but their concentration varies widely. Landfill gas cannot be distributed through utility natural gas pipelines unless it is cleaned up to less than 3% CO2, and a few parts per million H2S, because CO2 and H2S corrode the pipelines.Sony VAIO VGN-SR92S Battery

It is usually more economical to combust the gas on site or within a short distance of the landfill using a dedicated pipeline. Water vapor is often removed, even if the gas is combusted on site. If low temperatures condense water out of the gas, siloxanes can be lowered as well because they tend to condense out with the water vapor.Sony VAIO VGN-SR92US Battery

Other non-methane components may also be removed in order to meet emission standards, to prevent fouling of the equipment or for environmental considerations. Co-firing landfill gas with natural gas improves combustion, which lowers emissions.

Gas generated in sewage treatment plants is commonly used to generate electricity. Sony VAIO VGN-SR93DS Battery

For example, the Hyperion sewage plant in Los Angeles burns 8 million cubic feet (230,000 m3) of gas per day to generate powerNew York City utilizes gas to run equipment in the sewage plants, to generate electricity, and in boilers.[11]Using sewage gas to make electricity is not limited to large cities. Sony VAIO VGN-SR93JS Battery

The city of Bakersfield, California uses cogeneration at its sewer plants.[12] California has 242 sewage wastewater treatment plants, 74 of which have installed anaerobic digesters. The total biopower generation from the 74 plants is about 66 MW.

Biogas is usually produced using agricultural waste materials, such as otherwise unusable parts of plants and manure. Sony VAIO VGN-SR93PS Battery

Biogas can also be produced by separatingorganic materials from waste that otherwise goes to landfills. Such method is more efficient than just capturing the landfill gas it produces. Using materials that would otherwise generate no income, or even cost money to get rid of, improves the profitability and energy balance of biogas production.Sony VAIO VGN-SR93YS Battery

Anaerobic lagoons produce biogas from manure, while biogas reactors can be used for manure or plant parts. Like landfill gas, biogas is mostly methane and carbon dioxide, with small amounts of nitrogen, oxygen and hydrogen. However, with the exception of pesticides, there are usually lower levels of contaminants.Sony VAIO VGN-SR94FS Battery

Crystallized natural gas – hydrates

Huge quantities of natural gas (primarily methane) exist in the form of hydrates under sediment on offshore continental shelves and on land in arctic regions that experience permafrost such as those in Siberia (hydrates require a combination of high pressure and low temperature to form). Sony VAIO VGN-SR94GS Battery

However, as of 2010 no technology has been developed to extract natural gas economically from hydrates.

In 2010, using current technology, the cost of extracting natural gas from crystallized natural gas is estimated to 100%–200% the cost of extracting natural gas from conventional sources, and even higher from offshore deposits.Sony VAIO VGN-SR94HS Battery

Natural gas processing

The image below is a schematic block flow diagram of a typical natural gas processing plant. It shows the various unit processes used to convert raw natural gas into sales gas pipelined to the end user markets.Sony VAIO VGN-SR94VS Battery

The block flow diagram also shows how processing of the raw natural gas yields byproduct sulfur, byproduct ethane, and natural gas liquids (NGL) propane, butanes and natural gasoline (denoted as pentanes +).

Power generation

Natural gas is a major source of electricity generation through the use of gas turbines and steam turbines.Sony VAIO VGN-SZ35B/B Battery

Most grid peaking power plants and some off-grid engine-generators use natural gas. Particularly high efficiencies can be achieved through combining gas turbines with a steam turbine in combined cycle mode. Natural gas burns more cleanly than other Hydrocarbon fuels, such as oil and coal, and produces less carbon dioxide per unit of energy released.Sony VAIO VGN-SZ54B/B Battery

For an equivalent amount of heat, burning natural gas produces about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal.Combined cycle power generation using natural gas is thus the cleanest source of power available using hydrocarbon fuels, and this technology is widely used wherever gas can be obtained at a reasonable cost.Sony VAIO VGN-SZ55B/B Battery

Fuel cell technology may eventually provide cleaner options for converting natural gas into electricity, but as yet it is not price-competitive.

Domestic use

Natural gas dispensed from a simple stovetop can generate heat in excess of 2000°F (1093°C) making it a powerful domestic cooking and heating fuel.Sony VAIO VGN-SZ55GN/B Battery

In much of the developed world it is supplied to homes via pipes where it is used for many purposes including natural gas-powered ranges and ovens, natural gas-heated clothes dryers, heating/cooling and central heating. Home or other building heating may include boilers, furnaces, and water heaters. Sony VAIO VGN-SZ56 Battery

Compressed natural gas (CNG) is used inrural homes without connections to piped-in public utility services, or with portable grills. Natural gas is also supplied by independent natural gas suppliers through Natural Gas Choice programs throughout the United States. However, due to CNG being less economical than LPG, LPG (propane) is the dominant source of rural gas.Sony VAIO VGN-SZ561N Battery

Transportation

CNG is a cleaner alternative to other automobile fuels such as gasoline (petrol) and diesel. As of 2008 there were 9.6 millionnatural gas vehicles worldwide, led by Pakistan (2.0 million), Argentina (1.7 million), Brazil (1.6 million), Iran (1.0 million), and India (650,000).Sony VAIO VGN-SZ562N Battery

The energy efficiency is generally equal to that of gasoline engines, but lower compared with modern diesel engines. Gasoline/petrol vehicles converted to run on natural gas suffer because of the low compression ratio of their engines, resulting in a cropping of delivered power while running on natural gas (10%–15%). Sony VAIO VGN-SZ57N Battery

CNG-specific engines, however, use a higher compression ratio due to this fuel's higher octane number of 120–130.

Fertilizers

Natural gas is a major feedstock for the production of ammonia, via the Haber process, for use in fertilizer production.Sony VAIO VGN-SZ58GN Battery

Aviation

Russian aircraft manufacturer Tupolev is currently running a development program to produce LNG- and hydrogen-powered aircraft.[26] The program has been running since the mid-1970s, and seeks to develop LNG and hydrogen variants of the Tu-204 and Tu-334 passenger aircraft, and also the Tu-330 cargo aircraft. Sony VAIO VGN-SZ58GN/C Battery

It claims that at current market prices, an LNG-powered aircraft would cost 5,000 roubles (~ $218/ £112) less to operate per ton, roughly equivalent to 60%, with considerable reductions to carbon monoxide, hydrocarbon and nitrogen oxide emissions.Sony VAIO VGN-SZ58N Battery

The advantages of liquid methane as a jet engine fuel are that it has more specific energy than the standard kerosene mixes do and that its low temperature can help cool the air which the engine compresses for greater volumetric efficiency, in effect replacing an intercooler. Alternatively, it can be used to lower the temperature of the exhaust.Sony VAIO VGN-SZ61MN/B Battery

Hydrogen

Natural gas can be used to produce hydrogen, with one common method being the hydrogen reformer. Hydrogen has many applications: it is a primary feedstock for the chemical industry, a hydrogenating agent, an important commodity for oil refineries, and the fuel source in hydrogen vehicles.Sony VAIO VGN-SZ61VN/X Battery

Other

Natural gas is also used in the manufacture of fabrics, glass, steel, plastics, paint, and other products.

Storage and transport

Because of its low density, it is not easy to store natural gas or transport by vehicle. Natural gas pipelines are impractical acrossoceans.Sony VAIO VGN-SZ61WN/C Battery

Many existing pipelines in America are close to reaching their capacity, prompting some politicians representing northern states to speak of potential shortages. In Europe, the gas pipeline network is already dense in the West. New pipelines are planned or under construction in Eastern Europe and between gas fields in Russia, Near East and Northern Africa and Western Europe. Sony VAIO VGN-SZ640N/B Battery

See also List of natural gas pipelines.

LNG carriers transport liquefied natural gas (LNG) across oceans, while tank trucks can carry liquefied or compressed natural gas (CNG) over shorter distances. Sea transport using CNG carrier ships that are now under development may be competitive with LNG transport in specific conditions.Sony VAIO VGN-SZ645P3 Battery

Gas is turned into liquid at a liquefaction plant, and is returned to gas form at regasification plant at the terminal. Shipborne regasification equipment is also used. LNG is the preferred form for long distance, high volume transportation of natural gas, whereas pipeline is preferred for transport for distances up to 4,000 km over land and approximately half that distance offshore.Sony VAIO VGN-SZ650N/C Battery

CNG is transported at high pressure, typically above 200 bars. Compressors and decompression equipment are less capital intensive and may be economical in smaller unit sizes than liquefaction/regasification plants. Natural gas trucks and carriers may transport natural gas directly to end-users, or to distribution points such as pipelines.Sony VAIO VGN-SZ660N/C Battery

In the past, the natural gas which was recovered in the course of recovering petroleum could not be profitably sold, and was simply burned at the oil field in a process known as flaring. Flaring is now illegal in many countries. Additionally, companies now recognize that gas may be sold to consumers in the form of LNG or CNG, or through other transportation methods. Sony VAIO VGN-SZ670N/C Battery

The gas is now re-injected into the formation for later recovery. The re-injection also assists oil pumping by keeping underground pressures higher.

A "master gas system" was invented in Saudi Arabia in the late 1970s, ending any necessity for flaring. Satellite observation, however, shows that flaring[29] and venting[30] are still practiced in some gas-extracting countries.Sony VAIO VGN-SZ680ND Battery

Natural gas is used to generate electricity and heat for desalination. Similarly, some landfills that also discharge methane gases have been set up to capture the methane and generate electricity.

Natural gas is often stored underground inside depleted gas reservoirs from previous gas wells, salt domes, or in tanks asliquefied natural gas. Sony VAIO VGN-SZ691N/X Battery

The gas is injected in a time of low demand and extracted when demand picks up. Storage nearby end users helps to meet volatile demands, but such storage may not always be practicable.

With 15 countries accounting for 84% of the worldwide extraction, access to natural gas has become an important issue in international politics, and countries vie for control of pipelines.Sony VAIO VGN-SZ71E/B Battery

In the first decade of the 21st century, Gazprom, the state-owned energy company in Russia, engaged in disputes with Ukraine and Belarus over the price of natural gas, which have created worries that gas deliveries to parts of Europe could be cut off for political reasons.Sony VAIO VGN-SZ71VN/X Battery

Floating Liquefied Natural Gas (FLNG) is an innovative technology designed to enable the development of offshore gas resources that would otherwise remain untapped because due to environmental or economic factors it is nonviable to develop them via a land-based LNG operation. Sony VAIO VGN-SZ71WN/C Battery

FLNG technology also provides a number of environmental and economic advantages:

  • Environmental – Because all processing is done at the gas field, there is no requirement for long pipelines to shore, compression units to pump the gas to shore, dredging and jetty construction, and onshore construction of an LNG processing plant, which significantly reduces the environmental footprint.Sony VAIO VGN-SZ74B/B Battery
  • Avoiding construction also helps preserve marine and coastal environments. In addition, environmental disturbance will be minimised during decommissioning because the facility can easily be disconnected and removed before being refurbished and re-deployed elsewhere.Sony VAIO VGN-SZ750N/C Battery
  • Economic – Where pumping gas to shore can be prohibitively expensive, FLNG makes development economically viable. As a result, it will open up new business opportunities for countries to develop offshore gas fields that would otherwise remain stranded, such as those offshore East Africa.Sony VAIO VGN-SZ75B/B Battery

Many gas and oil companies are considering the economic and environmental benefits of Floating Liquefied Natural Gas (FLNG)However, for the time being, the only FLNG facility now in development is being built by Shell,[35] due for completion in around 2017.Sony VAIO VGN-SZ76 Battery

CO2 emissions

Natural gas is often described as the cleanest fossil fuel, producing less carbon dioxide per joule delivered than either coal or oil and far fewer pollutants than other hydrocarbon fuels. However, in absolute terms, it does contribute substantially to global carbon emissions, and this contribution is projected to grow. Sony VAIO VGN-SZ770N/C Battery

According to the IPCC Fourth Assessment Report (Working Group III Report, chapter 4), in 2004, natural gas produced about 5.3 billion tons a year of CO2 emissions, while coal and oil produced 10.6 and 10.2 billion tons respectively (figure 4.4). Sony VAIO VGN-SZ77N Battery

According to an updated version of the SRES B2 emissions scenario, however, by the year 2030, natural gas would be the source of 11 billion tons a year, with coal and oil now 8.4 and 17.2 billion respectively because demand is increasing 1.9% a year (Total global emissions for 2004 were estimated at over 27,200 million tons)Sony VAIO VGN-SZ780 Battery

In addition, natural gas itself is a greenhouse gas more potent than carbon dioxide when released into the atmosphere, although natural gas is released in much smaller quantities. However, methane is oxidized in the atmosphere, and hence natural gas has a residence lifetime in the atmosphere for approximately 12 years,Sony VAIO VGN-SZ78N Battery

compared to CO2, which is already oxidized, and has an effect for 100 to 500 years. Natural gas is mainly composed of methane, which has a radiative forcing twenty times greater than carbon dioxide. Based on such composition, a ton of methane in the atmosphere traps in as much radiation as 20 tons of carbon dioxide;Sony VAIO VGN-SZ791N/X Battery

however, it remains in the atmosphere for a 8–40 times shorter time. Carbon dioxide still receives the lion's share of attention over greenhouse gases because it is released in much larger amounts. Still, it is inevitable when natural gas is used on a large scale that some of it will leak into the atmosphere.Sony VAIO VGN-SZ84NS Battery

(Coal methane not captured by coal bed methane extraction techniques is simply lost into the atmosphere; however, most methane in the atmosphere is currently from animals and bacteria, not from industrial leaks .) Current estimates by the EPA place global emissions of methane at 3 trillion cubic feet (85 km3) annually, or 3.2% of global production.Sony VAIO VGN-SZ84PS Battery

Direct emissions of methane represented 14.3% of all global anthropogenic greenhouse gas emissions in 2004.

Other pollutants

Natural gas produces far lower amounts of sulfur dioxide and nitrous oxides than any other hydrocarbon fuel.Sony VAIO VGN-SZ84S Battery

Carbon dioxide produced is 117,000 ppm vs 208,000 for burning coal. Carbon monoxide produced is 40 ppm vs 208 for burning coal[citation needed]. Nitrogen oxides produced is 92 ppm vs 457 for burning coal. Sulfur dioxide is 1 ppm vs 2,591 for burning coal. Mercury is 0 vs .016 for burning coal.Sony VAIO VGN-SZ84US Battery

Particulates are also a major contribution to global warming. Natural gas has 7ppm vs coal's 2,744ppm.

Extraction

The practice of hydraulic fracturing, the process of using a combination of chemicals ranging from harmless to toxic to force natural gas to the surface from reservoirs with low permeability, has come under scrutiny internationally due to concerns about environmental and health safety, and has been suspended or banned in some countries.Sony VAIO VGN-SZ85NS Battery

Production

In mines, where methane seeping from rock formations has no odor, sensors are used, and mining apparatus such as the Davy lamp has been specifically developed to avoid ignition sources.

Some gas fields yield sour gas containing hydrogen sulfide (H2S). This untreated gas is toxic. Amine gas treating, an industrial scale process which removes acidic gaseous components, is often used to remove hydrogen sulfide from natural gas. Sony VAIO VGN-SZ85S Battery

Extraction of natural gas (or oil) leads to decrease in pressure in the reservoir. Such decrease in pressure in turn may result insubsidence, sinking of the ground above. Subsidence may affect ecosystems, waterways, sewer and water supply systems, foundations, and so on.Sony VAIO VGN-SZ85US Battery

Releasing the gas from low-permeability reservoirs is accomplished by a process called hydraulic fracturing or "hydrofracking". To allow the natural gas to flow out of the shale, oil operators force one to 9 million US gallons (34,000 m3) of water mixed with a variety of chemicals through the wellbore casing into the shale.Sony VAIO VGN-SZ94NS Battery

The high pressure water breaks up or "fracks" the shale, which releases the trapped gas. Sand is added to the water as a proppant to keep the fractures in the shale open, thus enabling the gas to flow into the casing and then to the surface. The chemicals are added to the frack fluid to reduce friction and combat corrosion. Sony VAIO VGN-SZ94PS Battery

During the extracting life of a gas well, other low concentrations of other chemical substances may be used, such as biocides to eliminate fouling, scale and corrosion inhibitors, oxygen scavengers to remove a source of corrosion, and acids to clean the perforations in the pipe.Sony VAIO VGN-SZ94S Battery

Dealing with fracking fluid can be a challenge. Along with the gas, 30% to 70% of the chemically-laced frack fluid, or flow back, returns to the surface. Additionally, a significant amount of salt and other minerals, once a part of the rock layers that were under prehistoric seas, may be incorporated in the flow back as they dissolve in the frack fluid.Sony VAIO VGN-SZ94US Battery

Use

In order to assist in detecting leaks, a minute amount of odorant is added to the otherwise colorless and almost odorless gas used by consumers. The odor has been compared to the smell of rotten eggs, due to the added butyl mercaptan. Sometimes a related compound, thiophane may be used in the mixture.Sony VAIO VGN-SZ95NS Battery

Explosions caused by natural gas leaks occur a few times each year. Individual homes, small businesses and other structures are most frequently affected when an internal leak builds up gas inside the structure. Frequently, the blast will be enough to significantly damage a building but leave it standing.Sony VAIO VGN-SZ95S Battery

In these cases, the people inside tend to have minor to moderate injuries. Occasionally, the gas can collect in high enough quantities to cause a deadly explosion, disintegrating one or more buildings in the process. The gas usually dissipates readily outdoors, but can sometimes collect in dangerous quantities if flow rates are high enough. Sony VAIO VGN-SZ95US Battery

However, considering the tens of millions of structures that use the fuel, the individual risk of using natural gas is very low.

Natural gas heating systems are a minor source of carbon monoxide deaths in the United States. Sony VAIO VGN-TZ121 Battery

According to the US Consumer Product Safety Commission (2008), 56% of unintentional deaths from non-fire CO poisoning were associated with engine-driven tools like gas-powered generators and lawn mowers. Natural gas heating systems accounted for 4% of these deaths. Sony VAIO VGN-TZ13 Battery

Improvements in natural gas furnace designs have greatly reduced CO poisoning concerns. Detectors are also available that warn of carbon monoxide and/or explosive gas (methane, propane, etc.).

Energy content, statistics and pricing

Quantities of natural gas are measured in normal cubic meters (corresponding to 0 °C at 101.325 kPa) or in standard cubic feet (corresponding to 60 °F (16 °C) and 14.73 psia). Sony VAIO VGN-TZ130N/B Battery

The gross heat of combustion of one cubic meter of commercial quality natural gas is around 39 megajoules (?10.8 kWh), but this can vary by several percent. This comes to about 49 megajoules (?13.5 kWh) for one kg of natural gas (assuming 0.8 kg/m^3, an approximate value).Sony VAIO VGN-TZ131 Battery

The price of natural gas varies greatly depending on location and type of consumer. In 2007, a price of $7 per 1,000 cubic feet (28 m3) was typical in the United States. The typical caloric value of natural gas is roughly 1,000 British thermal units (BTU) per cubic foot, depending on gas composition. Sony VAIO VGN-TZ132/N Battery

This corresponds to around $7 per million BTU, or around $7 per gigajoule. In April 2008, the wholesale price was $10 per 1,000 cubic feet (28 m3) ($10/MMBTU). The residential price varies from 50% to 300% more than the wholesale price. At the end of 2007, this was $12–$16 per 1,000 cu ft (28 m3).Sony VAIO VGN-TZ132N Battery

Natural gas in the United States is traded as a futures contract on the New York Mercantile Exchange. Each contract is for 10,000 MMBTU (~10,550 gigajoules), or 10 billion BTU. Thus, if the price of gas is $10 per million BTUs on the NYMEX, the contract is worth $100,000.Sony VAIO VGN-TZ150N/B Battery

European Union

As one of the world's largest importers of natural gas, the EU is a major player on the international gas market.

Gas prices for end users vary greatly across the EU. A single European energy market, one of the key objectives of the European Union, should level the prices of gas in all EU member states.Sony VAIO VGN-TZ150N/N Battery

United States

In US units, one standard cubic foot of natural gas produces around 1,028 British thermal units (BTU). The actual heating value when the water formed does not condense is the net heat of combustion and can be as much as 10% less.

In the United States, retail sales are often in units of therms (th); 1 therm = 100,000 BTU. Sony VAIO VGN-TZ160CB Battery

Gas meters measure the volume of gas used, and this is converted to therms by multiplying the volume by the energy content of the gas used during that period, which varies slightly over time. Wholesale transactions are generally done in decatherms (Dth), or in thousand decatherms (MDth), or in million decatherms (MMDth).Sony VAIO VGN-TZ160N/B Battery

A million decatherms is roughly a billion cubic feet of natural gas. Gas sales to domestic consumers may be in units of 100 standard cubic feet (Ccf).

As of 2009, the Potential Gas Committee estimated that the United States has total future recoverable natural gas resources approximately 100 times greater than current annual consumption.Sony VAIO VGN-TZ16GN/B Battery

Canada

Canada uses metric measure for internal trade of petrochemical products. Consequently, natural gas is sold by the Gigajoule, a measure approximately equal to 1/2 of a barrel (250lbs) of oil, or 1 million BTUs, or 1000 cu ft of gas, or 100cu metres of gas.Sony VAIO VGN-TZ16N Battery

Elsewhere

In the rest of the world, Natural gas is sold in Gigajoule retail units. LNG (liquefied natural gas) and LPG (liquefied petroleum gas) are traded in metric tons or mmBTU as spot deliveries. Long term Natural gas distribution contracts are signed in cubic metres, and LNG contracts are in metric tonnes (1,000kg). Sony VAIO VGN-TZ16N/B Battery

The LNG and LPG is transported by specialized transport ships, as the gas is liquified at cryogenic temperatures. The specification of each LNG/LPG cargo will usually contain the energy content, but this information is in general not available to the public.

In the Russian Federation, Gazprom sold approximately 250 billion cubic metres of natural gas in 2008.Sony VAIO VGN-TZ17/N Battery

Energy development is the effort to provide sufficient primary energy sources and secondary energy forms for supply, cost, impact on air pollution and water pollution, mitigation of climate change with renewable energy.

Technologically advanced societies have become increasingly dependent on external energy sources for transportation, the production of many manufactured goods, and the delivery of energy services. Sony VAIO VGN-TZ170N/B Battery

This energy allows people who can afford the cost to live under otherwise unfavorable climatic conditions through the use of heating, ventilation, and/or air conditioning. Level of use of external energy sources differs across societies, as do the climate, convenience, levels of traffic congestion, pollutionand availability of domestic energy sources.Sony VAIO VGN-TZ170N/N Battery

Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which arerenewable (naturally replenished.) Renewable energy is an alternative to fossil fuels and nuclear power, and was commonly calledalternative energy in the 1970s and 1980s. Sony VAIO VGN-TZ17GN/B Battery

htm" title="Sony VAIO VGN-TZ17GN/B laptop battery">In 2008, about 19% of global final energy consumption came from renewables, with 13% coming from traditional biomass, which is mainly used for heating, and 3.2% from hydroelectricity.[1] New renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels) accounted for another 2.7% and are growing very rapidly.Sony VAIO VGN-TZ17N Battery

The share of renewables in electricity generation is around 18%, with 15% of global electricity coming from hydroelectricity and 3% from new renewables.

Wind power is growing at the rate of 30% annually, with a worldwide installed capacity of 158 gigawatts (GW) in 2009, and is widely used in Europe, Asia, and the United States.Sony VAIO VGN-TZ18/N Battery

At the end of 2009, cumulative global photovoltaic (PV) installations surpassed 21 GW[6][7][8] and PV power stations are popular in Germany and Spain.[9] Solar thermal power stations operate in the USA and Spain, and the largest of these is the 354 megawatt (MW) SEGS power plant in the Mojave Desert.Sony VAIO VGN-TZ180N/RC Battery

The world's largestgeothermal power installation is The Geysers in California, with a rated capacity of 750 MW. Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugar cane, and ethanol now provides 18% of the country's automotive fuel.[11] Ethanol fuel is also widely available in the USA.Sony VAIO VGN-TZ185N/WC Battery

Climate change concerns, coupled with high oil prices, peak oil, and increasing government support, are driving increasing renewable energy legislation, incentives and commercialization. New government spending, regulation and policies helped the industry weather the global financial crisis better than many other sectors.Sony VAIO VGN-TZ18GN/X Battery

Scientists have advanced a plan to power 100% of the world's energy with wind, hydroelectric, and solar power by the year 2030,recommending renewable energy subsidies and a price on carbon reflecting its cost for flood and related expenses.Sony VAIO VGN-TZ18N Battery

While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas, where energy is often crucial in human development. Globally, an estimated 3 million households get power from small solar PV systems.Sony VAIO VGN-TZ190N/B Battery

Micro-hydro systems configured into village-scale or county-scale mini-grids serve many areas.[17] More than 30 million rural households get lighting and cooking from biogas made in household-scale digesters. Biomass cookstoves are used by 160 million households.Sony VAIO VGN-TZ190N/BC Battery

Wind

Wind power harnesses the power of the wind to propel the blades of wind turbines. These turbines cause the rotation of magnets, which creates electricity. Wind towers are usually built together on wind farms.Sony VAIO VGN-TZ191N/XC Battery

Wind power is growing at the rate of 30% annually, with a worldwide installed capacity of 158 gigawatts (GW) in 2009, and is widely used in Europe, Asia, and theUnited States.

At the end of 2010, worldwide nameplate capacity of wind-powered generators was 197 gigawatts (GW).Sony VAIO VGN-TZ195N/XC Battery

Energy production was 430 TWh, which is about 2.5% of worldwide electricity usage. Several countries have achieved relatively high levels of wind power penetration, such as 21% of stationary electricity production in Denmark, 18% in Portugal, 16% in Spain, 14% inIreland and 9% in Germany in 2010.Sony VAIO VGN-TZ198N/RC Battery

As of 2011, 83 countries around the world are using wind power on a commercial basis.

Hydroelectric

In hydro energy, the gravitational descent of a river is compressed from a long run to a single location with a dam or a flume. Sony VAIO VGN-TZ250N/B Battery

This creates a location where concentrated pressure and flow can be used to turn turbines or water wheels, which drive a mechanical mill or an electric generator.

In some cases with hydroelectric dams, there are unexpected results. Sony VAIO VGN-TZ250N/N Battery

One study shows that a hydroelectric dam in the Amazon has 3.6 times larger greenhouse effect per kW•h than electricity production from oil, due to large scale emission of methane from decaying organic material, though this is most significant as river valleys are initially flooded, and are of much less consequence for more boreal dams.Sony VAIO VGN-TZ250N/P Battery

This effect applies in particular to dams created by simply flooding a large area, without first clearing it of vegetation. There are however investigations into underwater turbines that do not require a dam. And pumped-storage hydroelectricity can use water reservoirs at different altitudes to store wind and solar power.Sony VAIO VGN-TZ27/N Battery

Solar

Solar power involves using solar cells to convert sunlight into electricity, using sunlight hitting solar thermal panels to convert sunlight to heat water or air, using sunlight hitting a parabolic mirror to heat water (producing steam), or using sunlight entering windows for passive solar heating of a building. Sony VAIO VGN-TZ270N/B Battery

It would be advantageous to place solar panels in the regions of highest solar radiation.

At the end of 2009, cumulative global photovoltaic (PV) installations surpassed 21 GW and PV power stations are popular inGermany and Spain. Solar thermal power stations operate in the USA and Spain, and the largest of these is the 354 megawatt (MW)SEGS power plant in the Mojave Desert.Sony VAIO VGN-TZ27N Battery

China is increasing worldwide silicon wafer capacity for photovoltaics to 2,000 metric tons by July 2008, and over 6,000 metric tons by the end of 2010. Significant international investment capital is flowing into China to support this opportunity.Sony VAIO VGN-TZ28/N Battery

China is building large subsidized off-the-grid solar-powered cities in Huangbaiyu and Dongtan Eco City. Much of the design was done by Americans such as William McDonough.

Agricultural biomass

Biomass production involves using garbage or other renewable resources such as corn or othervegetation to generate electricity.Sony VAIO VGN-TZ285N/RC Battery

When garbage decomposes, the methane produced is captured in pipes and later burned to produce electricity. Vegetation and wood can be burned directly to generate energy, like fossil fuels, or processed to form alcohols. Brazil has one of the largest renewable energy programs in the world, Sony VAIO VGN-TZ28N Battery

involving production of ethanol fuel from sugar cane, and ethanol now provides 18% of the country's automotive fuel.Ethanol fuel is also widely available in the USA.

Vegetable oil is generated from sunlight, H2O, and CO2 by plants. It is safer to use and store than gasoline or diesel as it has a higher flash point. Sony VAIO VGN-TZ290EAB Battery

Straight vegetable oil works in diesel engines if it is heated first. Vegetable oil can also betransesterified to make biodiesel, which burns like normal diesel.

Geothermal

Geothermal energy harnesses the heat energy present underneath the Earth. Two wells are drilled. One well injects water into the ground to provide water. Sony VAIO VGN-TZ290EAN Battery

The hotrocks heat the water to produce steam. The steam that shoots back up the other hole(s) is purified and is used to drive turbines, which power electric generators. When the water temperature is below the boiling point of water a binary system is used. Sony VAIO VGN-TZ290EAP Battery

A low boiling point liquid is used to drive a turbine and generator in a closed system similar to a refrigeration unit running in reverse. There are also natural sources of geothermal energy: some can come from volcanoes, geysers, hot springs, and steam vents.The world's largest geothermal power installation is The Geysers in California, with a rated capacity of 750 MW.Sony VAIO VGN-TZ295N/XC Battery

Tidal

Tidal power can be extracted from Moon-gravity-powered tides by locating a water turbine in a tidal current, or by building impoundment pond dams that admit-or-release water through a turbine. Sony VAIO VGN-TZ298N/XC Battery

The turbine can turn an electrical generator, or a gas compressor, that can then store energy until needed. Coastal tides are a source of clean, free, renewable, and sustainable energy.

Partager cet article

Repost 0
Published by batterys - dans Laptop Battery
commenter cet article

commentaires

gas plumbing 12/05/2012 14:45

The gas we have come to know as a source of energy has gone through a series of processes by the time it reaches us. Before natural gas is usable for fuel, it must be extensively processed to
remove all secondary components, such as propane and sulfur. The uses of natural gas are many and varied. Consumers, industries, and commerce can all benefit from its use. Here are just some
examples of the many uses of natural gas.

gas furnace 23/04/2012 06:04

Great info.. Thanks for sharing THE information about natural gas. I gathered huge information by your share. It will really very helpful for the people.

gas furnace 06/04/2012 13:17

Thanks for sharing an informative share about natural gas. Natural gas furnaces are efficient and durable. They are cheaper in rates. People prefer to use them in their homes. I think they are best
and suitable other than furnaces.

plumbing supplies 15/11/2011 21:37


Well gas are different talks.
The price is high and it pollutes our environment.