What is an LNG?LNG is the abbreviation of "Liquefied Natural Gas". It is natural gas mainly methane that is liquefied to enable easier transportation and storage. Liquefaction is conducted by cooling down natural gas to a temperature of -160 degree Celcius and stored at atmospheric presure. LNG contains mostly methane gas (CH4) and several other hydrocarbon gas such as ethane, propane, including heavy hydrocarbon such as butane, and pentane. Heavy hydrocarbon shall be limited in quantity not more than 01% in LNG which is usually stated in the sales agreement.
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LNG BADAK, BONTANG, EAST KALIMANTAN, INDONESIA
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A Video about LNG
LNG or liquefied natural gas only occupied a volume of 1/600 from the volume of natural gas in gaseous state. LNG is colorless, odorless, non toxic and non corrossive. Hazards of LNG among others are easy to burn, frost bite due to its cryogenic temperature.
General Process of LNG Manufacturing
First, gas is lifted from wells and flown to processing plant to be treated to remove condensate such as water, oil, sludge, also gases like CO2 and H2S. LNG plant is typically designed to remove mercury from feed gas to prevent formation of amalgam with aluminium at the cryogenic heat exchanger. This gas is then cooled in several stages until it liquefies to become LNG. LNG is then stored in a storage tank for loading onto LNG Tankers as per schedule.
Liquefaction process involves removal of certain components such as acid, helium, water, and heavy hydrocarbon that could cause problem downstream. Natural gas is condensed into liqued at near atmospheric pressure by cooling it down until -160 degree Celcius.
Volume reduction ratio of LNG is larger than CNG (Compressed Natural Gas). This makes LNG cheaper to transport long distance which is unreachable by pipeline. Specially designed Cryogenic ships (LNG carriers) or Cryogenic Tanker Road Truck are used to transport LNG.
In principal, LNG is used to transport natural gas to the market, where LNG is transformed back to natural gas and distributed in pipelines. High production cost and high storage costs requiring use of expensive cryogenic tanks had caused slow progress of LNG commercialization.
General Process of LNG Manufacturing
First, gas is lifted from wells and flown to processing plant to be treated to remove condensate such as water, oil, sludge, also gases like CO2 and H2S. LNG plant is typically designed to remove mercury from feed gas to prevent formation of amalgam with aluminium at the cryogenic heat exchanger. This gas is then cooled in several stages until it liquefies to become LNG. LNG is then stored in a storage tank for loading onto LNG Tankers as per schedule.
Liquefaction process involves removal of certain components such as acid, helium, water, and heavy hydrocarbon that could cause problem downstream. Natural gas is condensed into liqued at near atmospheric pressure by cooling it down until -160 degree Celcius.
Volume reduction ratio of LNG is larger than CNG (Compressed Natural Gas). This makes LNG cheaper to transport long distance which is unreachable by pipeline. Specially designed Cryogenic ships (LNG carriers) or Cryogenic Tanker Road Truck are used to transport LNG.
In principal, LNG is used to transport natural gas to the market, where LNG is transformed back to natural gas and distributed in pipelines. High production cost and high storage costs requiring use of expensive cryogenic tanks had caused slow progress of LNG commercialization.
LNG Demand Increasing
Nevertheless, LNG demand keep increasing in the last decade. This is due to world awareness of environmental sustainability keep getting better. The main reason of developed countries converts from using oil to using LNG as energy source is due to the fact that natural gas is less pollution to oil. This is because it burns more completely than oil or coal. Besides, oil prices keep increasing due to lack of supply and war in the middle east which makes developed countries began replacing it with LNG. Tsunami in Japan a few years ago also had increased the demand for LNG.
LNG UsageLNG eventually will be vaporized back to natural gas which is used for the followings:
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PT Badak luncurkan Bus berbahan bakar LNG, www.helfianet.com
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Why Natural Gas Needs to be Liquefied to LNG?
Typically natural gas consumers for power plants and household industries are significantly far from the source of natural gas itself. In 1970 a natural gas liquefaction technology was developed which is callled LNG Technology. With this kind of technology natural gas from the wells can be transported to consumers more economically. Why? This technology enable to liquefy natural gas into LNG. When natural gas is liquefied, its volume reduced significantly to only1/600 times of its original volume in gaseous state. By developing economic scale LNG vessels we can transport natural gas in form of LNG to consumers countries.
Typically natural gas consumers for power plants and household industries are significantly far from the source of natural gas itself. In 1970 a natural gas liquefaction technology was developed which is callled LNG Technology. With this kind of technology natural gas from the wells can be transported to consumers more economically. Why? This technology enable to liquefy natural gas into LNG. When natural gas is liquefied, its volume reduced significantly to only1/600 times of its original volume in gaseous state. By developing economic scale LNG vessels we can transport natural gas in form of LNG to consumers countries.
World LNG Producer Countries
According to US Energy Administration countries which produce LNG in the world consist of :
Total world LNG production keeps increasing from only 50 million tons per annum in 1990 to 130 million tons per annum in 2002, and 160 million tons per annum in 2007.
- Qatar: Qatar Gas I, II, III and Rasgas di Ras Lafan capacity of 4, 10, 7,8, dan 6,6 million tons per annum
- Aljazair: Arzew dan Skikda
- Brunai: Lumut capacity of 7,2 million tons per annum
- Indonesia: Arun, Badak, Tangguh capacity of 5, 22,6, and 7,6 million tons per annum
- Trinidad and Tobago: Atlantic LNG capacity of 9,9 million tons per annum
- Mesir: Damietta dan Idku capacity of 5,5 dan 7,2 million tons per annum
- Malaysia: Bintulu 1, 2, 3 capacity of 7,6, 7,8 dan 3,4 million tons per annum
- Nigeria: Nigeria LNG capacity of 23 million tons per annum
- Australia: Northwest Shelf, Whitnell Bay di Karatha capacity of 16,3 dan 7,7 million tons per annum
- Rusia: Sakhalin capacity of 9,6 million tons per annum
- Yaman: Yaman LNG di Balhaf capacity of 6,7 million tons per annum
- Oman: Qalhat capacity of 7,3 million tons per annum
- United Emirat Arab: Dash Island I, II capacity of 5,7 million tons per annum
Total world LNG production keeps increasing from only 50 million tons per annum in 1990 to 130 million tons per annum in 2002, and 160 million tons per annum in 2007.
LNG Manufacturing in the World
In the beginning LNG plant development was slow due to remote location and expensive cost of manufacturing and transportation. Building LNG plant requires not less than 1,5 billion dollars for each million ton per annum LNG produced. While cost for a receiving terminal is 1 billion dollars for each capacity of 1 bcf/ day, and LNG vessel price of 200 - 300 million dolars each.
In early 2000s, when more investors in natural gas liquefaction and regassification, and more sophisticated technology is available, cost of building LNG plant, receiving terminal and LNG vessel keep reducing that LNG manufacturing is becoming a competitive option for enery distribution. However, due to general inflation and lack of construction contractors the cost is increasing again in the last few years.
Price of LNG vessel size of 125,000 m3 at European and Japan shipyards is typically 250 million dollars. When Korean and Chinese are in competition the price reduced by 60%. However starting 2004 cost of LNG vessel is increasing again due to increasing demand.
Commercial development of LNG is called "value chain" where LNG supplier is first to ensure the sale to downstream buyers and than signing 20 - 25 years contract with tight price term and structure. Only when consumers have confirm and the project is feasible economically then the LNG project sponsors are willing to invest their funds to develop and operate. Therefore, LNG business is well known as rich people, where only strong financial and politic players can participate. Multinational companies like ExxonMobil, Shell, BP, Chevron and national oil company such as Pertamina and Petronas are the active players.
In early 2000s, when more investors in natural gas liquefaction and regassification, and more sophisticated technology is available, cost of building LNG plant, receiving terminal and LNG vessel keep reducing that LNG manufacturing is becoming a competitive option for enery distribution. However, due to general inflation and lack of construction contractors the cost is increasing again in the last few years.
Price of LNG vessel size of 125,000 m3 at European and Japan shipyards is typically 250 million dollars. When Korean and Chinese are in competition the price reduced by 60%. However starting 2004 cost of LNG vessel is increasing again due to increasing demand.
Commercial development of LNG is called "value chain" where LNG supplier is first to ensure the sale to downstream buyers and than signing 20 - 25 years contract with tight price term and structure. Only when consumers have confirm and the project is feasible economically then the LNG project sponsors are willing to invest their funds to develop and operate. Therefore, LNG business is well known as rich people, where only strong financial and politic players can participate. Multinational companies like ExxonMobil, Shell, BP, Chevron and national oil company such as Pertamina and Petronas are the active players.
Gas Liquefaction TechnologyNowadays there are four types of gas liquefaction processes:
Most of the gas liquefaction in these trains are using APCI or Cascade process technology. Other liquefaction processes such as DMR technology from Shell and Linde technology are used in smaller scales. 
Philip Cascade Process, Source: Saeid Mokhatab and Michael J. Economides, www.helfia.net
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Propane Pre-cooled Mixed Refrigerant Process (APCI Process), Source: Saeid Mokhatab and Michael J. Economides, www.helfia.net
APCI technology is the most popular to use in natural gas liquefaction in LNG train. About 86 trains of 100 which were build or under construction are using this technology with total capacity of 243 million tons per annum. The next commonly used technology is Cascade process from Philips which are used in 10 trains with a total capacity of 36.16 million tons per annum. On the other hand, DMR process from Shell is used in 3 trains with a total capacity of 13.9 million tons per annum, while Linde process from Statoil is only used in Snohvit at 4.2 million tons per annum from one train.
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Shell is currently is building a floating LNG at offshore field to produce, liquefy, store and transport LNG offshore before directly send to the market. This technology called Floating LNG is first developed by Shell and expected to finish in about 2017.
LNG Storage Tank
LNG storage tank is typically a full containment type, i.e: the outer wall is made of pre-stressed concrete and the inner wall is made of stainless steel with high nickel content and very efficient insulation between the two walls. Large tanks size of 95 - 170 thousand m3, have low height and width ratio and cylindrical with steel doom or concrete roof. Storage pressure in this kind of tank is very low. It is less than 1,45 psig. Sometimes a more expensive underground tank is used for storage. In small sizes like 700 m3 or less, it can be stored in horizontal or vertical high pressure vessels which is equipped with vacuum jacket.
LNG must be kept cool to keep it in liquid phase. Although it is using efficient insulation, heat in leak is still can not be avoided totally into LNG resulting in LNG vaporization. This vapor is called 'boil off gas' and is useful to keep LNG cool. Boil-off gas is typically compressed and used for fuel such as to generate electricity or reliquefy into the tank.
LNG must be kept cool to keep it in liquid phase. Although it is using efficient insulation, heat in leak is still can not be avoided totally into LNG resulting in LNG vaporization. This vapor is called 'boil off gas' and is useful to keep LNG cool. Boil-off gas is typically compressed and used for fuel such as to generate electricity or reliquefy into the tank.
Transportation
LNG is transported with special designed vessels with double hull to cover the cargo from damage or leak. There are several methods of leak detection available in the market to test the integrity of the membrane cargo tank of LNG vessels.
Price of an LNG vessel tanker is approximately 200 million dollars.
The important aspect in gas business is transportation and supplies since natural gas reserves are typically far away from gas consumer market. Natural gas is far larger in volume than oil to transport, and most is transported using pipelines. There are gas pipeline network in Uni Soviet, Europe and North America. Natural gas is lighter, even at higher pressure. Natural gas will travel much faster through high pressure pipeline, but it only can send about a fifth of energy per day due to its light properties. Natural gas is typically liquefied in form of LNG before being sent with ships.
LNG is transported in tanker using truck or railway and special designed ships called "LNG carrier". LNG is typically cool down to a cryogenic temperatur (below 100 degree Celcius) to increase tanker capacity. The first time of commercially transfer LNG from ship to ship was on February 2007 in Flotta, Scafa with 132.000 m3 LNG transferred from Excalibur Ship to Excelsior Ship.
Price of an LNG vessel tanker is approximately 200 million dollars.
The important aspect in gas business is transportation and supplies since natural gas reserves are typically far away from gas consumer market. Natural gas is far larger in volume than oil to transport, and most is transported using pipelines. There are gas pipeline network in Uni Soviet, Europe and North America. Natural gas is lighter, even at higher pressure. Natural gas will travel much faster through high pressure pipeline, but it only can send about a fifth of energy per day due to its light properties. Natural gas is typically liquefied in form of LNG before being sent with ships.
LNG is transported in tanker using truck or railway and special designed ships called "LNG carrier". LNG is typically cool down to a cryogenic temperatur (below 100 degree Celcius) to increase tanker capacity. The first time of commercially transfer LNG from ship to ship was on February 2007 in Flotta, Scafa with 132.000 m3 LNG transferred from Excalibur Ship to Excelsior Ship.
Safety and Incidents in LNG Plant
Natural gas is a fuel substance which is easily to burn. That is the reason why special efforts need to be prepared in design, construction and operation of LNG plant facilities to ensure safety and operation reliability.
In liqued form, LNG cannot explode and cannot be burnt. LNG must first be vaporized, then mixed with air at certain composition to get fire (range of flammability is between 5% - 15%), and then ignited to get burnt. If any leak, LNG will vaporize quickly, turns into gas and mixed with air. If air and gas mixture is in the flammability range of 5% - 15%, there is a risk of ignition that could result in fire hazard and heat radiation.
LNG ships had travelled over 100 millions miles without any accident that cause death or major accidents.
Several incidents that had occured related with LNG plant is as follows:
In liqued form, LNG cannot explode and cannot be burnt. LNG must first be vaporized, then mixed with air at certain composition to get fire (range of flammability is between 5% - 15%), and then ignited to get burnt. If any leak, LNG will vaporize quickly, turns into gas and mixed with air. If air and gas mixture is in the flammability range of 5% - 15%, there is a risk of ignition that could result in fire hazard and heat radiation.
LNG ships had travelled over 100 millions miles without any accident that cause death or major accidents.
Several incidents that had occured related with LNG plant is as follows:
- 1944, on 20 October. East Ohio Natural Gas Company experienced LNG Tank failure in Cleveland, Ohio. About 128 fatality due to explosion and fire. The tank was not equipped with dike wall. The tank is made of steel with very low nickel content so that the tank is becoming brittle when exposed to cryogenic LNG temperature. The tank was broken, throwing LNG into the sewer system of the city. LNG vaporizes and turned into gas which then exploded and fired.
- 1979 in October. LNG Plant Cove Point at Lusby, Maryland experienced pump seal failure that resulted in vapor release (not LNG) which got into electrical cable. A worker turned electrical breaker causing the gas vapor to ignite, killed one person, causing one more seriously injured and heavily damaged buildings. National fire codes were updated after the incident.
- 1983, in April. PT Badak NGL at Bontang, Indonesia experienced an explosion at Train-B Main Cryogenic Heat Exchangerduring a start-up. One person killed and many experience serious injuries. PT Badak NGL took expensive lessons learn from this incident and becoming on of the largest LNG complex in the world.
- 2004, on 19 January. LNG Plant Sonatrach at Skikda, Aljazair. An explosion Sebuah ledakan terjadi yang mengakibatkan 27 meninggal, 56 luka-luka, tiga train LNG hancur. Kecelakaan terjadi bermula dari ketel pembangkit uap (boiler) yang meledak mengakibatkan ledakan gas hidrokarbon yang besar. Ledakan terjadi di lokasi penyimpanan pendingin propan dan etan.
Natural Gas Procesing
Natural gas processing is a complex industrial process which is designed to purified feed gas by removing impurities (unexpected components) and various hydrocarbon other than methane and fluid to produce good quality natural gas to send through pipeline.
Natural gas treatment process starts from the 'well head'. Feed gas composition produced from production wells is depending on types, depth, and location of the deposit and underground geology in the area. Oil and gas often found together in the same reserve. Natural gas produced from oil wells typically is associated-dissolved group, meaning that the gas is carrying or dissolved in crude oil. Natural gas without crude oil carried-out with it is called as "non-associated". In year 2004, 75% or gas well production in America is non-associated.
Almost all natural gas production contains low molecule weight heavy hydrocarbon. For example methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10). Although these hydrocarbons are in liqued phase at underground pressure, they will become gas at atmospheric pressure. Altogether they are called as Natural Gas Liquid (NGL). Natural gas from coal and mining reserves (coalbed methane) is an exeption as it is a mixture of methane and 10 percent of CO2.
Natural gas processing plants are treating feed gas from underground field or from oil wells. Plants that are operating fully produce good quality natural gas for transporting via pipeline that can be used for fuel by commercial and industrial consumers. In the plants, unexpected substances are removed NGL hydrocarbon are extracted for other commercial usages. Due to economic reason, several plants are designed to produce interim products which usually contains more than 90% pure methane and small amount of nitrogen, carbon dioxide, and sometime ethane. This can be treated further at downsteam to be used as feedstock for chemical products.
Natural gas treatment process starts from the 'well head'. Feed gas composition produced from production wells is depending on types, depth, and location of the deposit and underground geology in the area. Oil and gas often found together in the same reserve. Natural gas produced from oil wells typically is associated-dissolved group, meaning that the gas is carrying or dissolved in crude oil. Natural gas without crude oil carried-out with it is called as "non-associated". In year 2004, 75% or gas well production in America is non-associated.
Almost all natural gas production contains low molecule weight heavy hydrocarbon. For example methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10). Although these hydrocarbons are in liqued phase at underground pressure, they will become gas at atmospheric pressure. Altogether they are called as Natural Gas Liquid (NGL). Natural gas from coal and mining reserves (coalbed methane) is an exeption as it is a mixture of methane and 10 percent of CO2.
Natural gas processing plants are treating feed gas from underground field or from oil wells. Plants that are operating fully produce good quality natural gas for transporting via pipeline that can be used for fuel by commercial and industrial consumers. In the plants, unexpected substances are removed NGL hydrocarbon are extracted for other commercial usages. Due to economic reason, several plants are designed to produce interim products which usually contains more than 90% pure methane and small amount of nitrogen, carbon dioxide, and sometime ethane. This can be treated further at downsteam to be used as feedstock for chemical products.
Type of Natural Gas Wells
Natural gas mostly comes from one of three types of wells: crude oil wells, gas wells, and condensate wells. Natural gas that comes from crud oil is called "associated gas". This type of gas can be presence as gas cover on top of crude oil at underground formation, or can be dissolved in the crude oil.
Natural gas from gas wells and condensate wells contain small amount of crude oil is called "non-associated gas". Gas wells typically is only producing natural gas, while condensate wells is producing natural gas together with other low molecular weight hydrocarbons. All other which are in liquid form at ambient temperature such as pentane, and heavier, are called "condensate".
Natural gas is called sweet gas if relatively free from hydrogen sulfide. Gas that still contained hydrogen sulfide is called sour gas. Natural gas or other gas mixtures contain quite significant hydrogen sulfide, carbon dioxide, are called acid gas.
Natural gas could also obtain from methane deposite inside coalbed porosity, and especially concentrated at adsorption condition on the surface of the coalbed. This type of gas is called coalbed gas or coalbed methane.
Natural gas from gas wells and condensate wells contain small amount of crude oil is called "non-associated gas". Gas wells typically is only producing natural gas, while condensate wells is producing natural gas together with other low molecular weight hydrocarbons. All other which are in liquid form at ambient temperature such as pentane, and heavier, are called "condensate".
Natural gas is called sweet gas if relatively free from hydrogen sulfide. Gas that still contained hydrogen sulfide is called sour gas. Natural gas or other gas mixtures contain quite significant hydrogen sulfide, carbon dioxide, are called acid gas.
Natural gas could also obtain from methane deposite inside coalbed porosity, and especially concentrated at adsorption condition on the surface of the coalbed. This type of gas is called coalbed gas or coalbed methane.