Talk:Liquefied natural gas
|This is the talk page for discussing improvements to the Liquefied natural gas article.|
|WikiProject Energy||(Rated B-class, High-importance)|
- 1 Energy Loss
- 2 CNG v LNG v LPG
- 3 Trade in LNG
- 4 The largest LNG train
- 5 LNG vapour hazards: toxicity and explosive
- 6 Boil-off gas acts to keep the LNG cold?
- 7 energy density
- 8 Expansion of LNG into gas phase
- 9 Merge of LNG spill page into LNG page
- 10 Rapid phase Transition (RPT)
- 11 LNG Importers globally
- 12 US west coast anti LNG activism
- 13 Costs
- 14 GOCE
- 15 MPa, not kPa
- 16 Units
- 17 Energy Density
- 18 Small Chinese Man?
- 19 LNG regassification plant
- 20 environmental concerns
Great if someone could add how much of the gas is lost in energy consumption in the liqudfaction process for a typical LNG train. (Appearently somewhere between 10-15%..but I have no figure on this)
For a smallish 1 million tonnes per annum plant, you're going to be looking at ~65MW of compressor power, so using a gas turbine (say 30% efficiency) gives 210MW of heat required. I think this is covered by the stream leaving the Reboiled De-ethanizer (5%ish of the total feed), so i guess to answer your question i'd say 5% of the feed is consumed in the liquefaction process. [Edit : Looking at it again today, 9% is probably closer to the mark]
In response to the above. A modern liquefaction train only requires 6-8% of the clean NG to fuel the gas turbine driven compressors. The specific power for the APCI C3MR (Propane percooled mixed refrigerant) and DMR (dual mixed refrigerant) processes are about 0.32-0.35 kwhr/kg of LNG. Chart, Linde and B&V Single mixed refrigerant process requires about 0.35-0.38 kwh/kg. The Conoco Phillips Cascade process and dual expander Nitrogen process requires about 0.40-0.50 kwh/kg. (David Franklin 22 July 2010)184.108.40.206 (talk) 14:26, 23 July 2010 (UTC)
I have sized several low efficiency dual expander nitrogen refrigeration process for liquefying natrual gas. 1.0 MTA requires 50MW (Trent 60 WLE of LM6000PG). A high efficency APCI process will liquefy about 1.2 MTA with 50 MW.(David Franklin 22 July 2010).220.127.116.11 (talk) 14:26, 23 July 2010 (UTC)
Note the the U.S. has over 100 small LNG peakshaver liquefiers. These plant range from 0.01 to 0.10 MTA and are much smaller than 1.0 MTPA. I would classify 0.5-2.5 MTA as mid scale projects and there is significant commercial interest in this range of of plants for both onshore and offshore floating applications. (David Franklin 23 Jul 2010)18.104.22.168 (talk) 14:26, 23 July 2010 (UTC)
German Wikipedia says about LNG transportation by ship, train or truck: This type of transport still plays a minor role in the western world, as about a quarter of the energy transported is needed for cooling the gas. --drylexx (talk) 10:15, 4 April 2008 (UTC) drylexx
It's higher over the entire process. From wellhead to storage tank about 30% of the energy in the gas is used to turn it into a liquid. There are also energy losses at the re-gassification plant at the other side (although these are much smaller since liquid -> gas is a natural process anyway at ambient conditions) —Preceding unsigned comment added by 22.214.171.124 (talk) 12:25, 7 April 2009 (UTC)
The above statement does not truthfully represent the industry. Energy required for liquefaction is highly dependant on the composition of the raw gas and methods used for gas treating and regasification. The condensate and LPG recovered in a rich associated gas stream more than pays for the entire pretreating of the LNG trains (reference Qatar). LNG just becomes an added bonus. For treating the gas, the turbine waste heat on the liquefaction train can be used to reboil the amine (acid gas removal) and regenerate the mol sieve dehydrators. Lean gas sources require much less processing and energy (~10%) of the heating value. The heat for regasification can be provided by consuming about 2% of the product or it can be supplied from the environment such as seawater or air. There are also ways to recover a significant amount of the energy used to liquefy the gas as electric power during the regas process. (David Franklin 22 July 2010)126.96.36.199 (talk) 14:26, 23 July 2010 (UTC)
CNG v LNG v LPG
I recently saw an article about a Japanese compressor that can turn the domestic gas to LNG (for converted cars) at home! What kind of pressure is used for LNG cars? Is it economical to liquefy gas at home? Kiumars
No, as you can't liquefy natural gas just by compressing it. Cold temperatures are required, even at elevated pressure.
I don't agree with the fact that "pipeline" natural gas is mentioned in the LNG section. It is misleading to mention Sulphur and other substances in that section. Would it not be wiser to create a "pipeline gas" paragraph or simply to refer the user to the natural gas section of wikipedia ?
Is the CNG-LPG bit relavent - this is the LNG article?
- Probably not. Propose to remove and add into relevant articles.Beagel (talk) 07:16, 3 February 2008 (UTC)
Trade in LNG
This is a bit pants, really. No references, and I think the pricing formula is wrong - 0.7 to 0.8 USD for how much LNG? It is common to quote LNG in tonnes, bcf, bcm, and MBtu. They use MBtu in Japan. It is very unusual to quote oil volumes in anything other that barrels (bbl), though I think they do in Japan. When working with prices, $/bbl or Yen/MBtu for oil is the way to go, then LNG is priced in $/unit-of-your-choice or Yen/MBtu. 188.8.131.52 (talk) 15:51, 3 January 2008 (UTC)Spangle
LNG sold to Japanese buyers is priced in US$/MMBtu. The pricing formula is not very clearly explain, but it looks to me that the 0.7-0.9 is the value of A in the formula - e.g. A+(B x Crude Oil) where A + 0.7-0.9 and B = 0.1485-0.1558. It would be neccesary to say what oil price this applies to to fit in with the S-curve described in the same paragraph.
I believe in 2010 and 2011 LNG trade accounts for 9-10% of the world natural gas demand. The 2004 number should really be updated. Also, I believe there are 18 exporters and 25 importers of LNG worldwide now. — Preceding unsigned comment added by 184.108.40.206 (talk) 13:36, 29 January 2012 (UTC)
The largest LNG train
The article states that the largest LNG train is the SEGAS Plant in Egypt with a capacity of 5 million ton per annum (mtpa). Actually the Train 4 of Atlantic LNG has capacity of 5.2 mtpa, which is claimed to be the largest train in operation (please see the references given in the Atlantic LNG article). Beagel (talk) 19:39, 14 January 2008 (UTC)
As of 23 Jul 2010, the largest operating LNG trains are at Qatargas Ras Lafan facility. These trains are 7.8 MTPA. Nigerian LNG has announced that they will construct train 7 at Bonney Island and it will be 8.4 mtpa. (David Franklin 23 July 2010) —Preceding unsigned comment added by 220.127.116.11 (talk) 12:56, 23 July 2010 (UTC)
LNG vapour hazards: toxicity and explosive
Anonymous editor 18.104.22.168 is repeatedly making edits asserting that LNG is toxic and explosive;
"The references cited in support of this claim do not constitute valid references, since the authors of those works did not perform experiments with unconfined methane vapor clouds. The claim that any methane-air mixture cannot result in an explosion in an unconfined environment is not supported by either logic (a negative cannot be proven) or the laws of physics. If anyone has a specific reference to a theoretical explanation why an unconfined methane-air cloud cannot explode, it should be posted here. Otherwise, the claim must not be permitted. Please note the failure of one or more experimentalists to achieve an unconfined explosion is not proof that one cannot occur: it merely indicates the experiments did not sustain the necessary conditions for an explosion. (A failure of experimental technique or subject matter expertise does not establish a physical law.) Unconfined methane gas explosions are documented in the mining industry."
LNG vapour is mostly methane, which is a molecule naturally produced by many animals and processes. It is not toxic, although the vapour is an asphyxiant and LNG is a cryogen (which means there is a freezing hazard).
LNG vapour, methane, does not explode in an unconfined space, according to many scientific and industry sources. The capability to cause an explosion relates to the speed of the flame front, and a methane flame front does not support sufficient velocity.   Pakaraki (talk) 08:23, 23 July 2008 (UTC)
Why? Because it is. It is toxic since asphxia (oxygen deprivation) is toxic to life (David Franklin Disagrees: By the same logic, water could be classified as an asphyxiant. Death by drowning is by asphixiation but we do not consider water toxic - Suggest that the editors remove such nonsence arguments). BY. Methane-air explosions are both theoretically and experimentally understood (http://gse.vsb.cz/2008/LIV-2008-2-8-14.pdf, for one example), and "confinement" is NOT a requirement for explosive property of a methane-air mixture. A chemical explosion of the methane-air mixture inside a container may produce a mechanical explosion by rupturing the container, but the container is NOT required for the explosion to occur. A container is used to conveniently mix the methane and the air in the correct proportions, but has no mechanistic contribution to the explosion phenomena whatsoever.
Of course, the hazard from LNG releases from the insulated container is the matter at hand. The LNG vapor (methane) mixes with air to produce an explosive composition.
Thus, the explosive hazard from LNG spills is related to the mixing of the methane vapor with air, creating an explosive mixture. The LNG industry should stop trying to misrepresent the hazard from LNG spills by stating the misleading information that "methane is not explosive". Methane is not at issue: the mixing of methane with air is the source of the explosive hazard. User:22.214.171.124
The cited Ukrane article relates to methane air mixtures within coal mines, which is a confined space and so creates conditions capable of supporting an explosion. The issue here should be one of physics, not a matter of discrediting the "LNG industry" or any other party. Please cite an authorative source that supports the assertion that an unconfined methane vapour cloud is capable of explosion. Pakaraki (talk) 19:23, 23 July 2008 (UTC)
In methane-air explosions or detonations, "confinement" is NOT a requirement for explosive property of a methane-air mixture. A chemical explosion of the methane-air mixture inside a container may produce a mechanical explosion by rupturing the container, but the container is NOT required for the explosion to occur. A container is used to conveniently mix the methane and the air in the correct proportions, but has no mechanistic contribution to the explosion phenomena whatsoever. Confinemen, even partial confinement, and obstacles can increase the intensity of a methane-air mixture explosion or detonation, but confinement is not a requirement for same.
Of course, the hazard from LNG releases from the insulated container is the matter at hand. The LNG vapor (methane) mixes with air to produce an explosive composition.
Thus, the explosive hazard from LNG spills is related to the mixing of the methane vapor with air, creating an explosive mixture. The LNG industry should stop trying to misrepresent the hazard from LNG spills by stating the misleading information that "methane is not explosive". Methane is not at issue: the mixing of methane with air is the source of the explosive hazard.
DISAGREE: Citing various references on "explosions" and relabeling them as "detonations" is not good science or practice. There are very clear definitions provided for both cited in several references. The definitions in NFPA 68: Standard on Explosion Protection by Deflagration Venting (Current Edition: 2007) are shown below. Deflagration: Propagation of a combustion zone at a velocity that is less than the speed of sound in the unreacted medium. Detonation: Propagation of a combustion zone at a velocity that is greater than the speed of sound in the unreacted medium. Subsonic burn may create a deflagration explosion. Supersonic burn may create a detonation explosion.
Unconfined methane cloud ignition is not likely to cause a detonation. Confined space ignitions can be accelerated to detonation. (David Franklin 30 April 2012). — Preceding unsigned comment added by 126.96.36.199 (talk) 14:40, 30 April 2012 (UTC)
DISAGREE: Methane-air mixtures are known to detonate (explode) in unconfined spaces. Please see the Gas Explosion Handbook, Chapters 2, 6, 11 for the technical basis and evidence for historical unconfined gas explosions for methane-air mixtures. This is available at: http://www.gexcon.com/index.php?src=handbook/GEXHBchap2.htm Confinement is not essential for a methane air mixture to explode. Please provide the physics theory that supports your assertion that confinement is essential for a methane-air detonation (explosion). The speed of the flame front argument is discredited by the Gas Explosion Handbook and fire engineering theory and practice.
An LNG spill outside of a closed insulated container results in vaporization of nearly pure methane gas, which mixes with the surrounding air containing oxygen. It is this air-methane mixture which is explosive.
Okay, here is the reference: . You must provide a reference for your assertion that methane-air mixtures cannot explode or detonate that is done by a primary author who performed experiments or presents theory,. The Hightower reference and the "Urban Legend" reference are not primary references and also do not prevent a theoretical basis for assertion that unconfined methane-air mixtures cannot under any circumstances explode or detonate. User:188.8.131.52
Just to clarify some terminology here, an explosion is "a sudden increase in volume and release of energy in an extreme manner". An explosion creates a shock wave. Technically this is also termed a detonation. As explained in the Gexcon document, sections 2.10 and 2.11, the difference relates to the flame front velocity. Sections 4.10 and 4.11 show that methane is rather lacking in flame speed and pressure build-up potential.
The Gexcon document covers a variety of substances, and there is nothing to suggest section 2.3 states methane clouds are capable of unconfined explosions. Many other types of gas are capable of this. Pakaraki (talk) 07:21, 24 July 2008 (UTC)
DISAGREE: Again, methane-air mixtures both detonate or explode, by any technical definition, whether confined or unconfined. Different fuel sources produce different intensities of detonation or explosion. Read the whole text and note the sections on unconfined gas explosions. The chart of the methane-air overpressure from detonations in unconfined gas form is clear in chapter 11 of the Gexcon reference, which states :"For otherwise equal conditions, the different fuels mixed with air will generate different explosion pressures." Figure 11.2 shows the overpressure created by an explosion of unconfined methane-air. The intensity of the explosion may be increased by obstructions, large gas cloud size, or confinement, but confinement is not necessary.
In the Gexcon reference, see Figure 5.28. "Explosion pressure for natural gas, propane and methane in air. This is unequivocal evidence of natural gas- air mixture explosion, unconfined." 184.108.40.206 (talk) 11:57, 24 July 2008 (UTC)
Please explain where the quoted phrase is from, it doesn't seem to be from the Gexcon document. In fact, the word "unequivocal" doesn't appear in chapter 5 at all. Figure 5.28 shows "results from the experiments in the 10 m wedge shaped vessel", that is, within a confined space. Thus it does not support the claims of anonymous editor 220.127.116.11.
In section 4.3 of the Sandia National Laboratories paper (reference below), tests conducted at China Lake in 1978 are outlined, reported by Parnaroukis et al 1980 and Lind and Watson 1977. These tests found "the methane-air mixture did not detonate". Pakaraki (talk) 18:53, 24 July 2008 (UTC)
The Gexcon document states in section 2.6: "if an unconfined cloud detonates the explosion pressure will be very high, in the order of 20 barg and in principle independent of confinement and obstructions." That means no confinement is required for an explosion/detonation. —Preceding unsigned comment added by 18.104.22.168 (talk) 18:09, 2 October 2008 (UTC)
DISAGREE: Pakaraki, you are either incapable of understanding the text or not dealing with this issue in good faith. Your writing is as a lawyer and not a scientist or engineer. If you read the text you would admit your error. You continue to post as if the text does not say what I have quoted. Further discussion is pointless.22.214.171.124 (talk) 01:50, 25 July 2008 (UTC)
So, to summarise here; the sentences quoted from the Gexcon document don't actually appear there, and so do not support the claim of anonymous editor 126.96.36.199. Secondly, cited figure 5.28 relates to experiments of mixtures in a vessel (that is, in a confined space) and therefore does not support the claim of unconfined explosions.
On the other hand, several references have been cited that explain unconfined methane-air mixtures do not explode. (See the Sandia, CH-IV and Shelly references below.) The Gexcon document cited gives further technical information about properties such as flame front speed and over pressure potential, to explain why unconfined methane-air mixtures do not detonate.Pakaraki (talk) 09:17, 25 July 2008 (UTC)
- Shelly, Craig. (2007). Liquefied Natural Gas: A New Urban Legend? Fire engineering. Vol 160 Issue 11. pg 109
- Hightower, Mike et al (2004) Guidance on Risk Analysis and Safety Implications of a Large Liquefied Natural Gas (LNG) Spill over Water, Sandia National Laboratories
- CH-IV LNG Information
- Gas Explosion Handbook, Chapters 2, 6, 11, available at http://www.gexcon.com/index.php?src=handbook/GEXHBchap2.htm
Boil-off gas acts to keep the LNG cold?
I'm not convinced "boil-off gas acts to keep the LNG cold" is the right perspective on latent heat of vaporization, which is what determines how much gas boils off when adding a given amount of heat. What the editor has in mind by this is presumably that as the temperature of LNG rises it hits a plateau at boiling point, like any liquid, with the latent heat of vaporization providing a buffer against further temperature increase. However temperature is much less relevant to boil-off than latent heat, which should be taken as the determinant of boil-off volume as a function of heat input. The perceived buffer here is an irrelevant temperature-dependent concept; at boiling point temperature becomes known exactly and therefore ceases to be relevant, all you care about is how much heat is continuing to enter the system. --Vaughan Pratt (talk) 17:23, 3 September 2008 (UTC)
- Yes, the boil off of vapour doesn't cool the LNG, it just acts to prevent temperature increasing (at a given pressure), which is much the same as saying it keeps it cold. Do you have some suggested alternative wording on this? Pakaraki (talk) 01:53, 10 September 2008 (UTC)
What is the energy density of LNG in MJ/kg ?
Expansion of LNG into gas phase
"Liquefied natural gas or LNG is natural gas (primarily methane, CH4) that has been converted to liquid form for ease of storage or transport. Liquefied natural gas takes up about 1/trillionth the volume of natural gas at a stove burner tip. It is odorless, colorless, non-toxic and non-corrosive. Hazards include flammability, freezing and asphyxia." As a rule of thumb, the expansion of liquid to gas at atmospheric pressure increases volume about a thousand fold. Where does 1/trillionth come from? —Preceding unsigned comment added by 188.8.131.52 (talk) 05:52, 9 November 2008 (UTC)
- Volume ratio between LNG and natural gas at standard temperature and pressure is about 600. --Pakaraki (talk) 17:54, 9 November 2008 (UTC)
at the burner tip the gas is about 3000degCelsius. Whatever the volume here, it would be much greater than at ambient temp. I'm assuming this is what was intended, and that the motivation for such a statement was sensationalism. I feel that it is irrelevant and causes confusion. propose that it be removed and replaced with volume at ambient temperature 600x cryogenic temperature (liquefied) ShearBlue (talk) 00:52, 9 July 2009 (UTC)
A spill of a fuel is a different type of thing than the fuel itself. The pages on oil and oil spill clearly distinguish between the two. As a result I do not think it is a good idea to merge the LNG page with LNG spill Lngdetails (talk) 15:11, 31 March 2009 (UTC)
- Agree, no merge. Also, the LNG page is already too long, and needs to be split. Perhaps the commercial (price, markets, etc) and safety topics would make good separate articles. --Pakaraki (talk) 06:08, 1 April 2009 (UTC)
Rapid phase Transition (RPT)
" One of the very rare risks of (propose semantics change 'of' to 'with') LNG is Rapid phase Transition (RPT) which arises from cold LNG being in contact with water." This sounds similar to Boiling Liquid Expanding Vapour Explosion (BLEVE). Although I realise that LNG is stored at atmospheric pressure and that RPT occurs as a result of rapid heat transfer as opposed to release of pressure in BLEVE, there is a need for clarification of RPT and possible comparison of RPT and BLEVE. ShearBlue (talk) 01:27, 9 July 2009 (UTC)
LNG Importers globally
"In 2005, Japan imported 58.6 million tons of LNG, representing some 30% of the LNG trade around the world that year. Also in 2005, South Korea imported 22.1 million tons and in 2004 Taiwan imported 6.8 million tons from camillo corp which is located in the chaotic state of Zimbabwe. These three major buyers purchase approximately two-thirds of the world's LNG demand. In addition, Spain imported some 8.2 mmtpa in 2006, making it the third largest importer. France also imported similar quantities as Spain."
(58.6 X 3) + (58.6 /3) = 175.8 + 19.5 = 195.3 mmtpa which represents, according to quoted figures for Japan's 2005 imports, 100% of Global LNG trade.
therefore (22.1 + 6.8) / 195.3 = 1/3 , according to "three major buyers purchase 2/3 of World LNG demand" -> this is FALSE. Why mention zimbabwe when discussing Importers, this is a distraction. Also, why mention Taiwan ahead of Spain or France, when T imports less than Spain, and HOW MUCH does F actually import, anyway??? This section is confusing. Propose it be revised. ShearBlue (talk) 01:21, 9 July 2009 (UTC)
- I've removed the unsourced reference to "camillo corp in the state Zimbabwe". It had been inserted at 12:25, 24 September 2008 from 184.108.40.206 at an Australian university, perhaps as an act of vandalism. I could not find any mention of that company in connection with LNG trade except in cloned Wikipedia text. Besides, Zimbabwe has no proven reserves of natural gas and as it is landlocked, there are certainly no LNG terminals there. Joewein (talk) 15:11, 9 September 2011 (UTC)
US west coast anti LNG activism
Reference 11 and 12 are identical. Same for 10 and 17. Several others point to different pages of the same site. Reference 16 just points to a search page on the same site. That is no reference at all. Activist sites can hardly be used as verifiable content. They have kind of a reputation for being biased. 220.127.116.11 (talk) 20:23, 27 November 2009 (UTC)
"The construction of an LNG plant costs at least USD 1.5 billion per 1 mmtpa capacity, a receiving terminal costs USD 1 billion per 1 bcf/day throughput capacity, and LNG vessels cost USD 0.2–0.3 billion."
Autochthony writes - might this be better in simple dollars - so readers appriate just how expensive these bits of kit - that ensure their lights stay on - really are?
Re-writing, for this page alone: - "The construction of an LNG plant costs at least US$ 1,500,000,000 per 1 mmtpa capacity, a receiving terminal costs US $ 1,000,000,000 per 1 bcf/day throughput capacity, and LNG vessels cost US $ 200,000,000 to 300,000,000 per ship."
|WikiProject Guild of Copy Editors|
MPa, not kPa
The unit LNG is measured in is typically "tonnes," "metric tons," or "metric tonnes" to be explicit. "Ton" is never used. Most common is "tonnes" or "million tonnes." 1 tonne = 1 metric ton = 1.1 tons, so they are not equivalent. That's why "mtpa" is more often used rather than "mmtpa" though both are technically correct. Many people in the industry even make this mistake. — Preceding unsigned comment added by 18.104.22.168 (talk) 13:18, 29 January 2012 (UTC)
Small Chinese Man?
Can I debate the validity of this change: https://en.wikipedia.org/w/index.php?title=Liquefied_natural_gas&diff=562509659&oldid=562353400
The changes aren't necessarily of value to the article's content... Changing
LNG regassification plant
The details of LNG regassification plant / technology are not given in this article. request experts to create a new article or add details in this article. 22.214.171.124 (talk) 16:01, 9 July 2013 (UTC)
Could someone help with referencing the start of this section, the original link was dead and Wiki prevents me from referencing it with this google stuff tagged on even though the report can be accessed. Type PacEnvCollisionCourse into google and use the first link