Liquefied Natural Gas - LIKE AN H-BOMB HAUNTING SOUTHERN CALIFORNIA


By Taylor Trowbndge

On the Mediterranean coast of Spain, the resort camp of Los Alfraques presented a portrait of serenity on the summer afternoon of July 11, 1978. Mothers were cleaning up after lunch or preparing coffee on gas burners. People in swimsuits had settled down for a siesta. Children were splashing in the water. From the busy highway alongside the camp there emerged a milky-white cloud. It drifted into the camp as an expanding white umbrella. The umbrella suddenly flared brightly and burst into flame. In only three minutes, the flames were burned out; exposing the blackened remains of cars, trees, tents, trailers -- and 102 human beings. Live people on fire ran insanely. Others were being scalded in the now boiling sea water.


A tank truck overfilled with a liquefied flammable gas called propylene had ruptured. Upon release to atmospheric pressure the liquid boiled violently, giving off gas at a temperature equal to its boiling temperature of -53ºF. The rapidly forming invisible gas cloud took on the white sheath because its boundaries froze moisture from the air. One of the gas burners for the coffee probably ignited it. Propylene is just one of a family of flammable gasses most conveniently transported after being liquefied through pressurization, refrigeration, or both. The monster of such gasses is LNG, liquefied natural gas.

In 1944, in Cleveland, an LNG storage tank ruptured. The fire destroyed the surrounding quarter mile of Cleveland. This was a tank 1/35th the size of today’s largest. All construction of LNG facilities then ended, until the energy crises of the 1970s and 80s. Then colossal LNG supertankers began entering the seaports of major cities in the U.S. and Europe. They contain 3,000 times the gas spilled from the tank truck that got Los Alfraques. Lee Davis in the book Frozen Fire details numerous minor (for LNG) accidents and some barely averted holocausts.

Since the 1980s, energy conservation and gas pipelines from Canada and Mexico had reduced demand and increased supply. The price of natural gas fell. The high expense of gas from LNG moth-balled two US terminals and shrank the use of the other two.

Recently the price of natural gas has been soaring. LNG supplied gas has become competitive. The US Energy Information Administration estimates a 28-fold increase in LNG imports over the next 20 years. For Southern California, a huge terminal is planned for the Port of Long Beach. Terminals about 13 miles offshore are planned off the state park of Leo Carrillo and the city of Port Hueneme.

THE TECHNOLOGY

Large supplies of natural gas occur overseas, but gas is much too voluminous for economical shipment by tanker. When cooled to -259 F it condenses into a liquid (LNG) and its volume decreases 600-fold. It may then be shipped in special supertankers. These consist typically of a series of five 25,000 cubic-meter (120 foot diameter) spherical “thermos bottles.” At the U.S. terminal, the LNG is transferred to a series of even larger “thermos bottles” for storage. Quantities may then be withdrawn as needed, warmed to the gaseous state, and supplied to the continental natural gas pipe lines.

The catastrophic threat of LNG lies in the combination of the staggering energy content of the unit quantities transported and the extremely treacherous way in which LNG acts upon spillage. Physicist Amory Lovins and other scientists compute that the described supertanker contains the energy equivalent of a one-megaton H-bomb (that’s a big one). Each of its tanks contains the equivalent of 10 Hiroshima bombs.
Liquids as frigid as LNG are referred to as cryogenic and have many exotic properties. For example, at such temperatures normally soft materials become hard as rock. A pencil eraser dipped in LNG can ring a bell.

Steel becomes more like glass. LNG spilled on hard materials creates a “thermal shock,” like cold water cracking an oven-hot dish. One cupful spilled on the metal deck of an LNG supertanker caused a meter-long crack. A recent Sandia National Lab summary of LNG hazard research (http://cryptome.org/lng-eyeball.htm) theorized that a large spill might break up a tanker, releasing its entire cargo.

Aiding the break up might be RPTs, “rapid phase transitions,” the popping and splattering from droplets of water seeping from frying meat into the hot grease and being vaporized so rapidly that they explode. Don’t try poring a cup of water into a vat of deep fryer grease, unless you are wearing a head-to-toe fire suit and were going to wash everything in your kitchen anyway. LNG spilled into water does the same thing, but on a colossal scale. A test at China Lake spilling just 11 ft3/sec produced a “pop” the equivalent of 14 pounds of TNT.

The worst threat of a large spill is that of a supertanker collision or grounding. Oil supertankers have a bad record because their large size makes them difficult to handle. LNG supertankers are as large. Worse, they float much higher in the water making them more difficult to handle in wind. In the 1970s a terminal was approved for Point Conception, which is the notorious “Cape Horn of the Pacific.”

Today the worst threat may be sabotage. The Sandia study treats this extensively, but a thorough study is Classified. The Pentagon considers the most lucrative target for terrorists to be facilities of LNG. A hijacked LNG tanker could make the World Trade Center destruction look like a car bombing. Congressman Ed Markey obtained intelligence that al Qaeda operatives infiltrated into the U.S. on LNG tankers docking in Boston Harbor.

POOL FIRE

Another treacherous aspect of the 300ºF temperature difference between the boiling point of LNG and the surroundings is that the spill vaporizes extremely rapidly, like water spilled on a 500ºF frying pan (300F above the boiling point of water). If ignited immediately upon spillage, a very short-lived but extremely large and intense flame occurs. A mathematical model presented in the journal “Fire Technology” (Feb. 1977) predicts that a spill from one of a ship’s 25,000 cubic-meter tanks into water would produce a miles-high flame that would radiate heat so intensely that it could start fires and fatally burn people over half a mile away. Federal Power Commission estimates agree. A 75,000 cubic-meter spill, the capacity of typically planned storage tanks, could inflame surroundings a full mile away. A tanker plus a previously proposed Los Angeles storage facility would total 275,000 cubic-meters. Even worst, a huge LNG fire might initiate a “fire tornado” (a fire spread by self-produced hurricane-velocity winds) testified Dave Surges of the Bureau of Mines. In World War II, a fire tornado destroyed Dresden, Germany, started by massive incendiary bombing.

VAPOR-CLOUD EXPLOSION

Immediate ignition of the boiling spill is not nearly the greatest hazard. If it does not immediately ignite, which many authorities claim is quite likely even amid the violence of a supertanker collision or a terrorist bombing, a cold dense gas-cloud forms. Such a cloud got Los Alfraques. This cloud spreads out hugging the surface, moves with the wind, and gradually mixes with air. As more air mixes in, proportions are reached at which the gas-air mixture becomes explosive. That is, if then ignited, this “vapor-cloud” explodes like the gasoline-air mixture in the cylinder of a car engine, instead of just burning like a pool of gasoline spilled on the ground. In explosive proportions the LNG gas-air mixture no longer hugs the ground nor seeks low places, but becomes neutrally buoyant. It neither rises nor sinks but moves with the air currents, parallel to the ground, over hills or mountains, around and among buildings. It continues until it has intercepted a large enough number of possible ignition sources for one to happen to set it off.

Worse yet, many researchers suspect that an extremely large cloud could “detonate,” explode like TNT. This is especially likely if the cloud engulfs obstructions, such as buildings. If the explosion becomes a detonation, much of this energy will be released in the much more destructive form of a “shock wave,” as it is in a nuclear explosion. Testers at the China Lake naval weapons test range in the Mojave Desert set off a small amount of high explosive in a culvert filled with a vapor similar to that from an LNG spill. A detonation wave formed in the culvert gas and propagated outside throughout an unconfined volume of the gas. The shock wave was felt at a town 14 miles from the test site. Authorities speculate that the speed of a vapor explosion wave accelerates with distance within the cloud. Inside a very large vapor cloud, as from ship-tank sized spill, the wave would have room to accelerate enough to become a detonation wave. The blast could be like that from tens of thousands of tons of TNT.

Ignition sources occur most abundantly in populated areas (gas stoves, pilot lights, cutting torches, etc.). A capricious property of a flammable vapor cloud is that it may pass unignited through many possible ignition sources. At first thought, this property seems fortunate. Ironically, this property is it’s most treacherous. The cloud will most likely pass unignited over water and through rural areas, where ignition sources are sparse, and ignite only when it reaches a community, where ignition sources are abundant. Science Applications, Inc. computes that it could actually engulf a square kilometer of city “before ignition is almost certain.” The vapor-cloud may act like a nuclear bomb with what might be called a “community-proximity fuse.” It may wander around with the winds until it comes across a community to go off in.

If it meets an insufficient number of possible ignition sources, it eventually mixes with so much air that it becomes nonflammable and thus safe. Estimates vary widely. The Sandia review proposed a distance of 1 or 2 miles. Under intense criticism the authors conceded 7 miles. What might they have proposed if they had not been funded by a notoriously dishonest, Big-Oil dominated government?

The best mathematical model of this by 1980 was that of Professor James A. Fay of the prestigious Massachusetts Institute of Technology. It predicts that a spill of just one of a tanker’s 25,000 cubic-meter tanks could remain explosive for 60 miles; a full 125,000 cubic-meter tanker load 135 miles. Although his model is considered extreme, it is credible, and most accurately fitted the experimental data.

Supporting such a much more extreme distance is that all existing tests are on spills a thousandth the size of a real tank. Even the Sandia report admits that a large spill would probably give much different behavior and that the mathematical models that fit the test spills may give gross underestimations for large spills.

Therefore, we may reasonably propose that any community within 135 miles of an LNG tanker must be in significant danger.

REMOTE SITES

The only reasonably sane approach to the LNG safety problem is location of terminals at least 135 miles from the nearest substantial community. However, there exists no point anywhere on either coast of the U.S. without a community of tens of thousands of people within even the 60-mile credible range of the one tanker-tank spill.

In Southern California conditions are especially treacherous. As every experienced surfer knows, onshore wind makes for bad surfing. The chop produced makes riding miserable. But during the night, the wind usually starts blowing offshore and lasts until midmorning. So surfers want to be on the waves early in the morning to have lots of time on the wonderful glassy surfaces. If an LNG spill occurs at night from an onshore terminal, such as that proposed for Long Beach, the gas cloud may blow out to sea without igniting. This sounds like a good thing, but as it travels it mixes with air and becomes capable of the vapor cloud explosion, and even possibly of a detonation. Around midmorning the wind turns it around and brings it to shore.

Far offshore, the winds are usually to the East both day and night. But East is toward land. A night spill at the once proposed Point Conception terminal would most likely blow out from shore into the Easterly winds, be carried down the channel of the Channel Islands, and come ashore, still explosive, onto the Ventura County coast after mid morning. Of course, along the way it could get diverted to Santa Barbara. The present “Clearwater” proposal, offshore from the Ventura County coast, would be right in the prevailing Easterly winds. A spill during the afternoon would most likely reach land at Port Hueneme, 13 miles away. But it could be diverted to anywhere in the Oxnard Plain. For the proposed terminal offshore from Leo Carrillo Park in the Santa Monica Mountains, the prevailing winds would most likely carry a vapor cloud to Venice, 37 miles away. Of course it could get diverted to Malibu or the South Bay.

A reasonably sane possibility for a remote docking and storage terminal would be of the order of 135 miles offshore, with regasified LNG piped to shore. Far beyond San Clemente Island, is the Cortes Bank, which gets as shallow as 45 feet. A terminal could be built there. The prevailing winds are to the East. A vapor cloud would have 140 miles to dissipate before reaching land, around San Diego. A 100-mile undersea pipeline would be required to get the regasified natural gas to the coast. The author knows of no economic study for such a project.

Safe and economical sites for LNG terminals may be nonexistent. (www.timrileylaw.com/LNG.htm)
It would make more sense to have the government subsidize solar electric with money than have individuals subsidize LNG with risks of holocausts to their lives and property.

(Taylor Trowbndge is an officer of the Southern California Federation of Scientists, www.scfs-la.org, scientists and engineers devoted to the public interest. See the web site for an expanded version of this article.)

Posted: Wed - November 1, 2006 at 04:43 PM          

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