Natural gas is composed primarily of methane, which is the simplest of hydrocarbons with one carbon atom and four hydrogen atoms. More than 65 million Americans use natural gas to heat their homes.
Liquefied Natural Gas (LNG) is simply natural gas that is cooled to minus 260° F, at which point it becomes a liquid that can be transported without high compression.
Converting natural gas to LNG reduces its volume by about 600 times, so it can be moved by tanker trucks and in ISO containers on roads and highways, or on the water.
Once delivered to its destination, the LNG is warmed and regasified so that it can be used just like existing natural gas.
Liquid Phase of Methane
Natural gas is the cleanest burning fossil fuel and is being used throughout the world to reduce harmful emissions. LNG is odorless, non-toxic and non-corrosive. LNG rapidly evaporates, leaving no residue (slick) on water or soil.Emissions:
EPA estimates that using LNG in heavy trucks would reduce emissions:
- Nitrous oxide (NOx) emissions by as much as 50%
- Greenhouse gases by as much as 23%.
LNG as a bunker fuel in ships (DNV-GL):
- Reduces carbon dioxide (CO2) emissions by 23%,
- NOx by 92%, and
- Sulfur oxide (SOx) by 90-95%.
LNG is not typically stored under high pressure and it is not explosive. LNG will stay in a liquid state at atmospheric pressure when the temperature of the liquid is at or below minus 260 degrees Fahrenheit.
LNG when vaporized back to a gaseous state (like the natural gas in a household), only burns when the natural gas-to-air ratio is between 5 and 15%. When the mixture of natural gas to air is less than 5% there is not enough gas to burn. Also, when the mixture is more than 15% natural gas to air, there is not enough oxygen for it to burn.
LNG as fuel:
LNG can be used to supplement or replace diesel fuel in High-Horsepower engines utilized in the shipping industry, the oil and gas industry, the rail industry, mining, and over the road trucking.
LNG must be stored and distributed with specialized equipment and stored in insulated tanks in order to keep the fuel in a liquid state at minus 260° F. This equipment must comply with standards specified by the National Fire Protection Association (NFPA).
LNG In The United States
LNG received a push through a crash research program launched in 1917, as the country entered World War I, to find cheap ways to extract large volumes of helium from natural gas and stockpile it.
The first commercial liquefaction plant was built in Cleveland, Ohio, in 1941. The East Ohio Gas Co. built a plant that could process about four million cubic feet of gas per day into LNG to be stored in three tanks at atmospheric pressure.
At the Cleveland plant, a storage tank built with low-nickel steel (nickel was in high demand for the war effort) failed in 1944. LNG spread into a sewer and an explosion killed 128 people. Many of the current regulations and safety measures associated with LNG manufacturing and storage can trace their roots to this event.
In January 1959, the world's first LNG tanker, the Methane Pioneer (a converted World War II Liberty freighter) carried liquefied natural gas from Lake Charles, La. to Canvey Island, United Kingdom.
The first commercial exports of liquefied natural gas from the United States occurred in 1969, with Alaskan LNG being sent to Japan from the Kenai Peninsula LNG plant.