Natural gas

Natural gas is a combustible natural gas, which is found in underground deposits. Frequently occurs along with crude oil, since it is formed in a similar manner. Natural gases consist mainly of highly flammable methane, but differ in their further chemical composition.

As fossil fuels, it is mainly used for heating residential and commercial premises, as a heat supplier for thermal processes in commerce and industry (eg in large bakeries, brick, cement plants, foundries and smelters ) for electrical power generation and small scale as a fuel for motor vehicles. In addition there are quantitatively significant applications as a reactant in chemical processes, where also its energy content is utilized. These are for example the synthesis of ammonia in the Haber- Bosch process (nitrogen fertilizers), the reduction of iron ore in the blast furnace process or the production of hydrogen.

• 2.1 History as an energy feedstock
• 2.2 Industrial use 2.2.1 Electricity and heat production
• 2.2.2 Fuel for motor vehicles

• 3.1 Search deposits
• 3.2 types of deposits 3.2.1 Conventional deposits
• 3.2.2 Unconventional deposits 3.2.2.1 Coal Seam Gas
• 3.2.2.2 Gas hydrates
• 3.2.2.3 Gas Tight
• 3.2.2.4 shale gas
• 3.2.2.5 aquifer

• 4.1 extraction 4.1.1 Drilling on land 4.1.1.1 Unconventional natural gas
• 4.1.1.2 Conventional natural gas

• 4.2.1 drying 4.2.1.1 Natural gas drying
• 4.2.1.2 Absorption drying with triethylene
• 4.2.1.3 drying with molecular sieve

• 4.3.1 Pipelines
• 4.3.2 LNG transport vessels
• 4.3.3 the conversion of methane in crude oil and methanol

• 5.1 World Promotions
• 5.2 Supply in Germany 5.2.1 German gas companies

Raw natural gas

Properties

Natural gas is a gas mixture whose chemical composition varies considerably depending on the archaeological site.

The main ingredient is always methane, the proportion in many natural gas deposits between 75 % and 99 % of the molar fraction. Natural gas often contains large proportions of so-called Ethan (often between 1 % and 15 % ), propane (often between 1% and 10 %), butane and ethene. Such a gas mixture is called wet natural gas, which has nothing to do with the water vapor present in most cases share, but that easily liquefiable gases under pressure means which are also called its natural gas liquids ( NGL).

Other minor ingredients are hydrogen sulfide ( commonly between 0% and 35%), which is removed by the desulfurization of natural gas, nitrogen ( often between 0 % and 15%, in extreme cases up to 70 %), carbon dioxide ( commonly between 0% and 10%) and water vapor. Natural gas with a high content of hydrogen sulphide and / or carbon dioxide are referred to as acid gases.

Hydrogen sulphide, carbon dioxide and water must in any case initially be separated, as some gases are poisonous or attack the pipeline or other - like water - could clog the pipeline by hydrate formation. This could be for a rig up to 28,000 tons per day. Of great value are natural gases which contain up to 7% helium. These are the major source of helium recovery.

In addition to these gases, natural gas can also be something elemental sulfur ( a few grams per cubic meter) and contain mercury (a few milligrams per cubic meter). These substances must first be separated, as they cause damage to the conveyor.

After the composition of various types of natural gas can be distinguished: H gas has a higher methane content ( 87-99 vol %), while L- gas (of English low ( (of English high ( calorific ) gas, natural gas with high energy content. ). calorific ) gas, natural gas with low energy content) for methane shares 80-87 % by volume of larger amounts of nitrogen and carbon dioxide.

• H- gas from the CIS consists of approximately 98 % methane, 1% other alkanes ( ethane, propane, butane, pentane ) and 1% inert gases.
• H gas from the North Sea, is about 89% of methane, 8 % of other alkanes ( ethane, propane, butane, pentane ) and 3% inert gases.
• L- gas from the Netherlands and Northern Germany consists of about 85 % methane, 4% other alkanes ( ethane, propane, butane, pentane ) and 11 % inerts.

The designations H and L gas refers to the distributed of the utility gas. On the side of the gas equipment is available with the standard ( DIN) EN 437, a similar classification, but is not congruent. This corresponds to L- gas type LL ( low-low ) and H - gas to the type E (Europe).

Natural gas is a flammable, colorless and usually odorless gas with an ignition temperature of approximately 600 ° C. It has a lower density than air. For the combustion of 1 cubic meter of natural gas about 10 cubic meters of air are needed. During combustion, the reaction products mainly water and carbon dioxide. In addition, small amounts of nitrogen oxides, sulfur dioxide, carbon monoxide and dust can still arise. To be able to possibly locate leaking natural gas, it is provided with a fragrance. In this odorisation priority thioether (eg, tetrahydrothiophene ) or alkanethiols (eg ethyl mercaptan and tertiary butyl mercaptan ) is added in very small quantities. These fragrances are responsible for the classic smell of gas.

Depending on the origin of the natural gas it may contain a substantial amount of strong-smelling organic sulfur compounds. With methods such as gas scrubbing these sulfur -containing natural gas attendants are largely removed, would arise from those harmful sulfur dioxide during combustion.

The natural gas types L and H differ not only in the composition ( see above ), but also in their physical properties.

• Density = 0.700 to 0.840 kg / m³ (L- gas - H- gas)
• Energy density ( L- gas - H- gas) Calorific value Hs (formerly Ho) / mass: 10-14 kWh / kg = 36 - 50 MJ / kg
• Calorific value Hs (formerly Ho) / Volume: 8.2 to 11.1 kWh / m³ = 30 - 40 MJ / m³
• The calorific value Hi (formerly Hu) is approximately 10 % below those levels.

Formation

Natural gas usually arises from similar operations such as oil and is therefore often found together with this. It forms the absence of air, elevated temperature and high pressure of dead and sunken marine micro-organisms (microorganisms, algae, plankton). Prevail low-oxygen conditions near the seabed, thus forming in the course of time thick sediment sequences with a high proportion of biogenic organic matter. The absence of oxygen in the depositional environment prevents the complete microbial degradation of the biomass, a sludge is formed. Over millions of years, this is exposed by overlap with other sediments high pressures and temperatures.

Larger quantities of natural gas are also formed as a result of microbial decomposition of organic matter on the spot, without significant migration. Gas accumulations with this history can be found for example in the foothills of the Alps in Upper Austria and Upper Bavaria. With a development time of about 20 million years, they are considered very young.

Helium may be contained in the natural gas when helium is produced in lower than the deposit minerals from radioactive alpha decay and diffuses upward.

Use

History as an energy feedstock

The Chinese used natural gas for salt extraction Already years ago, about 2000.

In 1626, French missionaries reported about " burning springs" in shallow waters of North America. A major industrial use of natural gas began in the U.S. in 1825 in the village of Fredonia. Here WH Hart put on a shaft for natural gas for lighting a mill and a residential building. Hart took advantage of natural gas for illuminating a lighthouse on Lake Erie. He founded in 1858 the first gas company, the Fredonia Gas Light Company. Beginning in 1883, natural gas in Pittsburgh and Pennsylvania has been in the glass and steel industries. Difficulties were the construction of a pipeline system.

North America, particularly the U.S., to 1950 had the highest use of natural gas in the world ( the U.S. share of funding in 1950 about 92 % of world production, 1960 U.S. funding share of world production 80.2 %). In West Germany the energy use of natural gas in the early 1960s was only 1 % of fossil primary energy. In 1970, there were about 5 % of fossil primary energy in West Germany.

Natural gas was originally only burned in the recovery of petroleum. First, natural gas was (since the beginning of the 1920s ) and later in Europe used in the U.S. ( since the 1960s ) as an energy feedstock for the economy.

In some countries, natural gas is burned off still, since the transport of the gas is expensive. Many gas - and - steam power plants have been built based on natural gas for power generation in the U.S. in recent years, these have a very high efficiency ( 60%) and can do is use the waste heat for district heating for heating of residential buildings.

At present (2013 ) is natural gas with 25 % share of fossil fuels is a very important energy resource. Natural gas is according to the International Atomic Energy Agency (IAEA ) having a 50 % share by the year 2080 most important fossil fuels.

Industrial use

Electricity and heat production

Natural gas is used in Germany and in many other industrialized countries, mainly to supply useful heat in the industrial and residential buildings. In some countries, the production of electricity from gas plays a major role (Russia: about 50 % share). In Germany, the share of natural gas in electricity production has been declining for several years, he was still 10.5% in 2013. Natural gas is converted into electricity in gas turbine power plants and combined cycle power plants. These power plants are used in Germany in the first place to cover peak load, the performance of gas turbines used there can be - compared to coal and nuclear power plants - good ( timely ) are regulated.

Fuel for motor vehicles

Natural gas for several years increasingly used as a fuel for motor vehicles, and in this context because of its compressed and liquefied form as CNG Compressed Natural Gas ( CNG ) or LNG liquefied natural gas ( LNG ).

At gas stations, natural gas is available as an H- gas and / or L- gas, the H- gas has a slightly higher energy content than the L- gas (see data). The energy content of 1 kg of natural gas (H- gas) corresponds to about 1.5 liters of gasoline or 1.33 liters of diesel. In October 2011, more than 75,000 natural gas -powered vehicles in Germany were admitted, and growing. The increase was, according to KBA in September (2011) 85% of the previous month. In October 2011 there were already 894 natural gas filling stations in Germany. Alternatively biogas can be filled even with CNG vehicles.

The advantage of natural gas is the opposite of petrol or diesel ( and also against liquid ) cleaner combustion and therefore the tax advantage granted. The German federal government lowered with the " Law on the further development of the ecological tax reform " in 2002 for all vehicles on public roads the mineral oil tax rate for natural gas until 31 December 2020 and for liquefied until 31 December 2009. This law was in 2006 revised so that now natural gas and LPG are equally favorable tax until 31 December 2018. Reduced by the tax breaks, the price of natural gas is currently around 0.98 to 1.09 € compared to a liter of unleaded petrol (based on energy content, the amount of natural gas fueled measured in mass ( kg) ).

The automotive industry offers standard gas models since 1995. However, it is not available as a natural gas vehicle each model. Retrofitting of gasoline vehicles is relatively complex, the conversion will cost between € 2,400 and € 3,200. In most production vehicles, the tanks are located under the floor, so limitations in the use of the trunk omitted. CNG filling stations remove the gas to the natural gas network and compress it to a pressure of 200. The fueling is carried out in stages until the final pressure of 200 bar. Due to the existing infrastructure of the gas system, the construction of a transport and distribution network is eliminated. However, this results in the disadvantage that the gas supply is not guaranteed outside of the gas network and usually omitted for cost reasons. There are numerous local transport companies in the public transport that operate their buses with natural gas, but also taxi companies and logistics companies such as TNT.

CNG is an alternative to the HCNG, a mixture of compressed natural gas and hydrogen.

Occurrence

1844 natural gas was found in the area of ​​Vienna Ostbahnhof in Europe for the first time. 1892 was followed by discoveries in Wels. In the 20th and 21st century Exploited large gas fields are the Troll field in Norway, the North Field in Qatar and the Urengoy gas field in Russia. Furthermore, even suspected large, untapped gas fields in Iran. Methane in gas hydrates is suspected in a large quantity not only in the area of the continental shelf, but also in permafrost in Siberia, Canada and Alaska.

The United States is in addition to Russia, the country with the highest production rate for natural gas. They promoted about 524 billion cubic meters of gas in 2006. By 1999 they had made ​​94,000 holes in their own country.

Search deposits

The aim of natural gas exploration is the discovery of natural gas deposits. Of primary interest are types of deposits that can be exploited by conventional funding procedure with relatively little effort. Such occurrences are accordingly called conventional deposits. Explorations undertaken by geologists and geophysicists private or public oil and gas companies therefore focus on identifying geological conditions that make the presence of conventional reserves in the ground probably.

Conventional natural gas deposits consist of a porous and permeable, saturated with natural gas reservoir rock, which is located below a geringporösesn impermeable rock layer, the caprock. Storage and caprock must be part of a geological structure, which only allows for the accumulation of gas to mineable quantities in addition. Such structures are called natural gas traps. The natural gas can as neither up nor escape laterally, and is, as it is located deep underground, under high pressure.

The interpretation of satellite images or aerial photographs or recorded by classical mapping surface geology can be used to identify fossilized sedimentary basins. Maybe give the terrain encountered natural gas outlets ( eg mud volcanoes ) direct evidence of gas reserves in the ground. First detailed studies of the geology of the deeper subsoil often done by seismic measurements. Here are pressure waves (in principle sound ) generated by explosions in shallow wells or with the help of vibrators, sent to earth. The sound waves are going back by certain strata, known as reflectors to the surface where they are detected by highly sensitive vibration knives, called geophones. From the time differences between " launch " of the wave and registration by the geophones gives the depth of individual reflectors. When sound sources and measurement points are arranged reticulate at the surface can be made of the data determined a three-dimensional seismic model of the subsurface are created ( 3D seismic ). From this model, knowledge of the subsurface geology can be obtained, shall be determined by those on which areas of the region seismically explored further exploration work is focused.

An especially promising places sample wells are drilled. Here, the interpretation of the seismic model with the actually drilled geology is balanced and refined accordingly. The encountering gas-saturated sedimentary rocks in a predicted depth then confirms the interpretation of a recognizable structure in the seismic profile as a natural gas case.

If one is interested after the start of promotion for changes in fluid content of a deposit, called a 4D seismic survey can be carried out. Here you can see the costs from subsidizing changes or remaining stocks a deposit.

Deposit types

Conventional deposits

The hitherto most undeveloped natural gas reservoir type are gas deposits in porous and permeable rocks ( eg sandstones, Massenkalke ) below low porous, impermeable rocks ( shales, marls, fine-grained limestones ). The gas here is increased in the pore space of permeable rocks from even greater depths up ( migrated), where the more direct ascent is prevented by the impermeable caprock. However, Special requirement for the formation of a deposit the existence of geological structures, which prevent lateral migration of the gas below the caprock and thus possible at all an accumulation of larger amounts of gas then known as reservoir rock porous rock. Such structures, which can be both sedimentary and tectonic origin, are called natural gas traps. This can be " drowned " fossil Riffkörper or the flanks of a salt dome and others.

Very often occurs natural gas because of its lower density in the uppermost regions of a petroleum deposit. This is called cancer associated ( " oil vergesellschaftetem " ) of natural gas. Pure oil reservoirs without gas are rather the exception, as in petroleum source rocks always also forms gas and both migrated together into the reservoirs. The waste in the oil production, natural gas is separated and processed separately or, " flared " particularly in the offshore oil production, basic ( that is, still burned in place of funding). Because natural gas has a much higher mobility than oil, whose migration flows more freely. Therefore, pure natural gas deposits conventional type, so-called non -associated natural gas, relatively common.

Unconventional deposits

Deposits are described as unconventional, do not match the conventional gas trap type. 40% of total gas production from unconventional deposits are already being promoted in the United States.

Coalbed methane

Also coalbed natural gas is bound. Methane is adsorbed by charcoal on its large internal surface in significant quantities. In greater depths can be included and promoted accordingly more by venting and pumping by the higher pressure coal proportionately more natural gas.

In the U.S., 10% of the natural gas is extracted from coal seams, these were in 2002 about 40 billion cubic meters. In the U.S., 11,000 wells have been drilled to develop this type of deposit. In Germany, the natural gas reserves are estimated in coal seams at about 3000 billion cubic meters. Worldwide it is estimated the reserves of natural gas in coal seams on 92000-195000 billion cubic meters.

Gas hydrates

At high pressure and low temperatures, methane, together with a water ice-like solids, so-called methane hydrates. One cubic meter of gas hydrate contains about 164 cubic meters of methane gas. In the ocean floors of today's continental shelves and hanging, from about 300 meters below sea level, and in permafrost, there are substantial deposits. But the methane is presumably only partially " leaky " natural gas deposits. The other part comes from the activity of microorganisms in the soil and seabed.

Tight Gas

" Tight gas " found in " destroyed " reservoir rocks ( so-called tight gas sands or tight gas carbonate ), that is, in rocks that were once porous and permeable enough that natural gas could hineinmigrieren there. Progressive diagenesis with increased compaction of the reservoir rock or additional growth of mineral grains led to a significant reduction of the pore space and a loss of pore interconnectivity. Due to the concomitant loss of permeability, natural gas production is impossible with conventional methods from these rocks.

After a general definition of tight gas reservoirs, the term can not be profitably cultivated by conventional funding procedure referred to all non- conventional reserves, although they lie deep beneath the earth, but do not provide or economically viable quantities of natural gas. Under these definitions are not only natural gas deposits in diagenetic " destroyed " reservoir rocks but also shale gas and coalbed methane deposits.

Shale gas

In contrast to tight gas shale gas ( " shale gas " ) is not even gotten into a (originally ) more porous rock to migrate, but is still in its mother rock, a primary carbon-rich mudstone ( " oil shale " in the broadest sense).

Aquifer

In addition, may be dissolved in very deep groundwater layers of the aquifer, a significant amount of natural gas.

Stocks

The amount of natural gas contained in reservoirs is, according to estimates by the Federal Institute for Geosciences and Natural Resources of the world's natural gas resources and reserves at 819,000 billion cubic meters of natural gas. Here are natural gas reserves, that is, at present technically and economically recoverable quantities, at 192,000 billion cubic meters. In most consistent gas production of about 3,200 billion cubic meters, equivalent to a static range of about 60 years. These figures include the combined analysis of conventional and for some years now commercially funded non-conventional natural gas and includes shale gas ( shale gas ), coal seam gas ( coal bed methane, CBM ) and natural gas in tight sandstones and carbonates ( tight gas ). Tight gas is now produced mainly in the United States, with a strict demarcation of conventional natural gas no longer takes place. In Germany, natural gas produced from tight sandstones and reported together with conventional natural gas for years. This does not include the resources of aquifer gas and natural gas from gas hydrate, as currently is still open, if and when this potential can be used commercially. Overall, there is a potential of up to 1,800,000 billion cubic meters.

On the situation of conventional and unconventional deposits of oil and natural gas on Earth → see oil production.

Natural gas industry

Extraction

Natural gas is extracted by drilling either in pure gas fields or as a by-product of oil production. As natural gas is usually under high pressure ( sometimes around 600 bar) is, so to speak, it promotes itself as soon as the reservoir is opened once. Over time, the gas pressure of the deposit decreases steadily. The exploration is performed nowadays initially with three-dimensional physical seismographs, then by geochemical methods, and finally through a well bore.

Drilling on land

Unconventional natural gas

Conventional natural gas

When drilling for natural gas is often a depth of 4 - 6 km, with exploration drilling can sometimes reach up to 10 kilometers. There are also drills that can drill into the rock not only vertically but also horizontally diagonally up (especially for offshore drilling developed ). During drilling, the rock must be destroyed and transported upward, a coat must protect the Bohrhohlraum.

The so-called rotary drilling the drill bit is in a jacketed drill string to a pulley in the derrick: attached (height 20 to 40 meters). When drilling instabilities in the rock and a loss may occur in drilling fluid, so pipe runs must be introduced to the stability of the drilling process (also called casing ). In the subsequent stage is then drilled with a smaller diameter. The hole diameter increases with increasing depth from (from about 70 cm to 10 cm). In the cladding layer, an aqueous clay solution flows to the cooling of the drill bit to stabilize the borehole and to promote the cuttings. Between the production string and the well casing, a sealing sleeve is in the hole just above the gas -bearing layer - called Packers - attached. In the head of the casing is the main valve - for opening and closing of the gas flow - is mounted. In addition to measuring devices, valves, pipe connections are to be forwarded.

The gas sensor is completed to the surface through the xmas tree, which consists of two main valves, one of which is equipped as an automatic Sicherheitsabsperrschieber, the probe will automatically lock in critical operating conditions. From borehole away the derivation of the gas over other slider and the nozzle is done - usually with an operating pressure of about 70 bar - to a collection.

Drilling costs account for up to 80 % of expenses at the development costs of a new natural gas field.

Meeresbohrtechnik

The first offshore drilling was carried out in 1947 by the United States. Later fixed drilling platforms were constructed with extensible legs. It could be reached depths of several hundred meters.

Finally, floating platforms ( "Offshore Drilling Units" ) and drill ships were developed. Here, the well head is shifted to the seabed. It has managed to advance with such rigs until in 3000 meters water depth.

Processing

Dehydration

Natural gas drying

Drying of natural gas, that is, the removal of water or higher hydrocarbons, is an essential process in the natural gas processing.

In case of insufficient drying can result in the formation of methane hydrates. The solid methane hydrates may contribute to an extreme pressure drop in the pipeline and damage the valves and piping. Drying also guarantees a constant calorific value of the gas at the gas supply to the public network.

And measures the degree of drying of natural gas to the dew point. In general, a dew point is sought at -8 ° C.

For gas drying among others the following methods are known:

Absorption drying with triethylene

In the absorption drying gas is brought into an absorption column with triethylene glycol (TEG ) in contact. TEG is highly hygroscopic and thus deprives the gas the water. The contact of the two media is carried out in countercurrent. The gas flows into the column from below upwards. Contrary to this, the triethylene glycol is in the column inserted above and removed the bottom. Prerequisite for good water absorption is a large contact surface between gas and the TEG, and therefore a structured packing is installed in the column. In the pack, the TEG widely distributed.

The discharged from the column triethylene glycol is recycled in a regeneration plant. In an evaporator by heating the water absorbed and removed in smaller amounts also hydrocarbons from the triethylene glycol.

The evaporator is heated by hot combustion gases which are generated in a combustion chamber separately prepared. In the combustion chamber also formed during the regeneration Brüdengase be burned. Thus, the need for additional fuel fed is reduced. In addition, the Brüdengase must not be consuming condensed and disposed of.

Drying with molecular sieve

The drying process of gases by means of molecular sieve is usually in several stages:

Pre-drying by heat exchanger or other kinds of water separators. Here the gas is cooled and removed by the separator, large amounts of water. The residual water content in the gas after this process is still too high to compress it sufficiently and liquefy with it.

After pre-drying the gas enters sorbents. These are at least two tanks which are filled with a molecular sieve. The gas is first forced through adsorber No. 1. The liquid portion is absorbed by molecular sieve ( adsorbed). This adsorption process can take up to 12 hours or more.

Then the gas stream is diverted to adsorber 2 and the adsorbent No. 1 " is " in the regeneration phase. In the regeneration of hot air, nitrogen or natural gas is forced at a temperature from about 280 ° C through the boiler. Thereby, the fluid retained by the molecular sieve molecules are again removed and transported out of the tank. Thereafter, the cooling of the molecular sieve is carried out for several minutes to hours. An adsorption and regeneration phases is called the cycle.

At the gas outlet, a dew point of up to 110 ° C can be achieved.

The molecular sieves used in the drying gas can be specifically designed for the various gas compositions. Often not only water molecules, but also hydrogen sulfide and hydrocarbons must be removed from the gas. In most cases, a 4A molecular sieve is ( having a pore opening diameter of 4 Å ) were used. There are also situations, a combination of different types of passes for which to apply.

Separation of carbon dioxide and hydrogen sulphide

The separation of carbon dioxide and hydrogen sulphide is carried out by chemical or physical means.

The two gases can be bonded in a high boiling solvent, together with a base such as N -methylpyrrolidone ( Purisol process).

In physical separation, for example, the Sulfinol process, a high-boiling polar organic liquid contains a little water, are used. The Sulfinol process the solvent used is a mixture of diisopropanolamine ( DIPA ), tetrahydrothiophene dioxide ( sulpholane ) and water.

Separating nitrogen

Nitrogen and helium can be deposited by low-temperature separation from natural gas. In a high pressure separation apparatus, a nitrogen-enriched gas stream rises to the top of methane gas flowing to the bottom of the column. This process step can be coupled with the liquid gas production (LNG).

Radioactive waste

In December 2009, the public has been known that in the oil and gas production each year millions of tons of radioactively contaminated residues are incurred for the disposal largely missing evidence. As part of the promotion pumped to the surface sludge and wastewater NORM substances (Naturally Occurring radioactive material), and the highly toxic and extremely durable radium and polonium 226 210 The specific activity of the waste is from 0.1 to 15,000 becquerels ( Bq) per gram. In Germany, where about 1,000 to 2,000 tons of dry matter occur in the year, the material is, according to the Radiation Protection Ordinance of 2001 in need of monitoring already from a Bq per gram and should be disposed of separately. The implementation of this Regulation, the responsibility of the industry has been left so that the wastes were ultimately eliminated away carelessly and improperly for decades. There are documented cases in which waste with an average of 40 Bq / g were stored on a premises without any marking and should not be specially marked for transport.

In countries with larger subsidized quantities of oil or gas caused significantly more waste than in Germany, however, there is no country in an independent, continuous and seamless recording and monitoring of contaminated residues from oil and gas production. The industry is going to vary with the material: In Kazakhstan, vast tracts of land are contaminated by these wastes, the UK's radioactive residues in the North Sea are conducted. In the United States there are in almost all states due to the radioactive contamination from oil production increasing problems. In Martha, a community in Kentucky, Ashland Inc., the company has thousands of contaminated feed pipes to farmers, nurseries and schools sold without informing them of the contamination. Were measured up to 1100 micro Roentgen per hour, so that the elementary school and several houses had to be evacuated after the discovery of radiation immediately.

Transport

Natural gas is transported ( the term gas transmission therefore ) mainly through pipelines, called pipelines, even over long distances. Major pipelines for the integration of Western Europe, the natural gas is purchased from Russia for the most part, are among other Nord Stream ( North European Gas Pipeline ), the Soyuz pipeline and gas pipeline Yamal-Europe.

Natural gas can be compressed by a technical method or transferred to other states of matter, enable transport without pipelines. Common to all methods is a reduction in volume, which means that they are better suited as a replacement for fuel from petroleum among other things. Process for natural gas compression:

• Compressed natural gas (CNG - Compressed Natural Gas) (compression, storage in pressure vessels)
• Liquefied natural gas ( LNG - Liquefied Natural Gas) ( liquefaction by gas liquefaction plant )
• GTL (gas -to-liquids ) (conversion to liquid hydrocarbons via Fischer- Tropsch synthesis)

Piping

The pressure in gas pipes designed differently depending on the transport and distribution. The existing steel - distance transportation pipelines on the mainland have a diameter of about 1.4 m, are under a pressure of about 84, and are laid usually about a meter below the ground. Every 100 to 150 km has to make a compressor station for the new pressure. A further transportation of natural gas can - depending on the design, height profile and flow rate of a line - lead to significant energy consumption by pumping. 4700 kilometers about 10 % of the energy of the natural gas must be used to operate the pump. To limit the dangers of leaks that could allow an unimpeded flow gas outlet, slides are also mounted in a pipeline at certain intervals. In a control center of the pipe pressure of the gas network can be remotely monitored. This network is operated by the transmission system operators.

For the regional distribution of natural gas there is a special, denser network system of regional operators, with a pipeline pressure of about 16 bar. For the transport of natural gas to the regional municipalities there is a third network which only has a gas pressure below 1 bar, and for households having a gauge pressure of only 20 mbar. Sometimes, the corresponding plastic tubes.

In Germany, the high-pressure natural gas network in 2002 had a length of about 50,000 kilometers, network with low pressure lines to the house connections had a length of 370,000 kilometers.

For the construction and operation of natural gas networks shall, depending on the soil ( rock, sand ) and geography ( cross rivers with culverts, rail lines, highways, etc.) high amounts are applied. The procurement or value of a gas network is difficult to estimate the extent and also depends on the business model from (future income value ).

The five natural gas transit pipelines in Austria reported in 2006 throughout nominal pressure 70 bar and the following nominal diameter: Trans- Austria gas pipeline with three parallel strands ( about 380 km long), with 900 up to 1050 mm, West-Austria -Gas-Pipeline (245 km) 800 mm ( shorter 100 km :) Hungarian - Austria gas pipeline and the Penta West 700 mm and South-East gas pipeline 500 mm. TAG was given ( to 2006 Wildon ) a second tube, TAG derived from 1970 received 2009 2011 new compressor in Neustift and Baumgarten.

LNG transport vessels

For sea transport the natural gas is liquefied by cooling to -160 ° C. Special LNG tankers can absorb 160,000 tons of liquefied natural gas. For LNG carriers, there are two types: the ball and the membrane - tankers. A total of 130 LNG carriers were constructed by the year 2000.

As of 4000 km or 2000 km by land sea this mode of transport is economically more favorable than the transport through a pipeline system.

Conversion of methane in crude oil and methanol

Lighter than natural gas can be transported in pipelines or oil tankers. This crude oil was free of sulfur and heavy metals and thus environmentally friendly. The petroleum company Sasol ( South Africa) and Shell ( Malaysia) already presented in 1997 from natural gas crude oil, which located use as a diesel additive. This was based on the conversion of methane by oxygen to synthesis gas (CO 3 H 2). Synthesis gas can be converted to crude oil under high pressure and high temperatures according to the Fischer- Tropsch synthesis.

Since the process of high temperatures, pressures and pure oxygen required, you soon tried to improve the reaction conditions for the conversion. The company Syntroleum Company ( Tulsa, USA ) developed a method that instead of pure oxygen produced good yields of crude oil with air. Critical with respect to the cost is the lowest possible transition temperatures. It was tested a variety of catalysts for such conversion. The company would like to achieve the conversion of natural gas in a single reaction step.

The Pennsylvania State University has succeeded by means of a catalyst to convert methane at less than 100 ° C in methanol.

Storage

To compensate for load variations in the supply of natural gas underground gas storage facilities were built. A BDEW spokesman said that there were 46 underground gas storage facilities in Germany. Your capacity amounts to nearly 20 billion cubic meters of working gas. This corresponds to almost a quarter of the 2007 natural gas consumed in Germany. In Austria, the capacity is 5 billion cubic meters, making it a percentage even higher.

Sometimes used underground salt caverns as storage for natural gas. To create the storage cavity pumping water through a hole in a geological salt formation. Here, the salt will dissolve in a controlled process and the resulting brine is discharged through the same hole. As so-called pore storage but can also serve emptied of oil and gas deposits. Short-term capacity have so-called tube memory with 50 to 100 bar, which are routed meander several meters deep in the ground, for example, can be part of a disused gas pipeline.

The much smaller above-ground gas storage are mainly used for daily demand fluctuations. Instead of the previous towering Gasometer (usually telescopic wheel and gas tank) high-pressure gas tank ball are now used, which are operated at about 10 bar overpressure.

Supply

World subsidies

The net world production of natural gas (natural gas) including petroleum gas, less back pressed and flared gas and less power consumption in 2010 was about 3239.5 billion cubic meters, of which Russia and the U.S. with 19 % world share the main producing countries. Russia promoted in 2010 as the U.S. 611 billion cubic meters of natural gas. Other important producing countries are Canada with 4.9% (160 billion cubic meters ), Iran 4.3% ( 139 billion cubic meters), Qatar with 3.6% (117 billion cubic meters ), Norway, China, Saudi Arabia, Algeria, Netherlands and Indonesia. Germany promoted 14.2 billion cubic meters ( 0.4%).

This covered natural gas in 2010 about 24 % of global energy consumption. Major consumers of natural gas are the U.S., Russia, Iran, China, Germany, and Japan.

Supply in Germany

Until the early 1980s, the gas supply of most West German cities of city gas, which is toxic due to the high proportion of carbon monoxide was converted to natural gas. Without major modifications, this was possible. In the former GDR, we completed the changeover predominantly only in the 1990s.

For over 25 years, there are considerations to build a terminal in Wilhelmshaven for LNG carriers to reduce dependence on imports via pipelines.

At the top cover, to balance short-term import disruptions and fluctuations in demand in Germany about 18.6 billion cubic meters of natural gas stored in underground storage facilities.

The use of natural gas in Germany is subject to a natural gas tax, the standard rate is currently at € 5.50 per megawatt-hour (ie 0.55 cents per kWh).

In the pricing of natural gas in Germany, the oil -price plays a big role. The cartel of gas price due to the intra-industry agreement of an oil price maintenance contrary, however, after a widespread perception violates European and German competition law. The Bundesgerichtshof ( BGH) decided on 24 March 2010 that gas suppliers their prices are no longer allowed to bind exclusively to the development of the oil price.

By the Federal Office of Economics and Export Control ( BAFA ), import and export prices of natural gas are recorded monthly, and also the quantities for individual supplier countries listed.

Between 1991 and 1999, the import price of natural gas per Terajoule averaged about 1700-2200 €. Between 2001 and 2004, the gas import price per Terajoule was 3200-4200 €. In 2006, the gas import price per Terajoule temporarily increased to over 6,000 €. In November 2008, the import price for natural gas was at € 8,748 per Terajoule, in September 2009 at € 4,671. Price increases for natural gas are not transparent for consumers.

German gas companies

The largest German producer of natural gas, the natural gas and oil BEB GmbH (Hannover). The largest natural gas distribution companies in Germany are E.ON Ruhrgas (Essen), RWE Energy (Dortmund ), VNG - Verbundnetz Gas (Leipzig), Wingas (Kassel ), Shell ( Hamburg) and ExxonMobil (Hannover). The transport (pipelines ) is guaranteed by the so-called transmission system operators, including Open Grid Europe (Essen), Ontras (Leipzig), GASCADE (Kassel ) and Terra BW Nets (Stuttgart).

The sales to end users via approximately 700 gas utilities, especially public utilities. For most of the related natural gas acquires E.ON Ruhrgas of the Russian company Gazprom and Gasunie of the Netherlands and the Norwegian producer.

Ecological aspects

Due to the low level of impurities, natural gas burns cleaner in general over other fossil fuels. Nevertheless, production, transportation, processing and combustion of natural gas to the release of the greenhouse gases methane and carbon dioxide contribute. Due to the higher calorific value on burning of gas up to 25% carbon dioxide produced as a heating oil.

Problem, however, if natural gas is not profitably sold as a by- product of oil production, or can be pumped back into the earth and is flared. Through various flare -down programs of the petroleum industry flaring is reduced and the natural gas processing and a controlled, cleaner energy use are supplied, replacing other energy sources. This causes a significant improvement in the global ecological balance and is therefore encouraged through tax advantages. If once natural gas is no longer sufficiently available, the sustainability of the investments can be guaranteed in regional gas networks by increasing production and incorporation of biogas.

The development of shale gas ( shale gas) may be associated with significant environmental consequences, such as the experience in the U.S. show.

Go through material specific leaks leaked components of the natural gas directly into the atmosphere or absorbed from undersea leak in the sea water. With sufficient depth and therefore high pressure and sufficiently low temperature, the methane content of the natural gas can be deposited as solid methane hydrate in the deep sea.

Safety aspects

Oil could entail some risk of accident due to his explosiveness, which eg for improper use of in households of accidents to catastrophic events (eg gas explosion of Chuandongbei, gas explosion in Belgium ) may result.

On March 25, 2012 it was discovered that emanates from an unknown leak on the gas (and oil ) production platform Elgin PUQ the Group total in the North Sea under water gas. Because of fire and explosion due to spillage of the air and gas due to the toxicity of hydrogen sulfide gas contained in the safety zones of up to 5.6 km radius were for ships and aircraft furnished and adjacent platforms evacuated.