Why is natural gas liquefied?

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Experts say that natural gas liquefaction solves the problems of storing and transporting natural gas over long distances. Natural gas becomes 625 times smaller after being liquefied at low temperatures. A standard liquefied gas tank truck with a capacity of 35 cubic meters can transport 21,000 cubic meters of natural gas. Liquefied gas tank trucks function as pipelines for natural gas on highways; wherever roads are available, liquefied natural gas can be transported, and liquefaction technology enables natural gas to be moved from one place to another. Liquefied natural gas can be turned back into a gaseous state for use with a simple vaporization device. Liquefied natural gas can be used to address the peak-shaving challenges in urban gas networks. Natural gas liquefaction overcomes the disadvantages of high costs associated with laying pipelines over long distances, limited coverage areas, and the lack of storage and peak-shaving capabilities. Experts believe that natural gas liquefaction has the following advantages: 1. Liquefied natural gas is easier to transport in an economical and reliable manner. Specialized liquefied natural gas tankers and ships are used to transport the natural gas from gas fields, after it has been liquefied, over long distances to sales locations. This approach reduces losses resulting from the release of large amounts of natural gas. It requires significantly less investment compared to pipeline transportation, is convenient and reliable, carries low risks, and has high adaptability. 2. It facilitates the balanced regulation of urban load. Since civilian gas consumption is higher in winter and lower in summer, or due to maintenance work at chemical plants that use gas, technical upgrades at LNG plants, or even failures in the gas transmission networks, this can lead to irregularities in gas supply on a regular or irregular basis. Building LNG storage tanks can help to balance these fluctuations by reducing peak demands and covering low-demand periods. According to foreign statistics, over 100 liquefied natural gas peak-shaving facilities have been built and put into operation in the United States, Japan, and Europe. They save land, capital, and construction time compared to above-ground high-pressure gas storage tanks and underground gas reservoirs, and they are also convenient and flexible, not being restricted by geological conditions. 3. The cooling energy released during the production process can be recycled. For example, the cold energy generated when liquefied natural gas is vaporized can be used for refrigeration, freezing, cryogenic crushing, and thermoelectric power generation. Therefore, some peak-shaving facilities are built in conjunction with refrigeration plants. With the current technological level of liquefied natural gas production, 50% of the energy consumed in natural gas liquefaction can be recovered and reused. Additionally, the boil-off gas from liquefied natural gas tanks can also be recovered and reused locally. Low-temperature liquefaction can also separate out some useful by-products. 4. Liquefied natural gas can be used as a high-quality fuel for vehicles. Compared to cars that use gasoline, it has advantages such as a high octane rating, good resistance to detonation, complete combustion, less exhaust pollution, a longer engine life, and reduced transportation costs ； Even compared to compressed natural gas vehicles, it features higher storage efficiency, a longer driving range per refueling, as well as lower pressure in the onboard cylinders, less weight, and a smaller number of cylinders ； Advantages such as the ability to build a site without being restricted by gas supply networks. 5. It is relatively safe for production and use. Liquefied natural gas has a high ignition point and high explosion limit, and it is lighter than air; therefore, any slight leakage spreads upward immediately, preventing accumulation that could lead to an explosion. It is precisely because liquefied natural gas has the properties of low temperature, light weight, and easy evaporation that it can be prevented from being stolen or sold, thereby avoiding losses. 6. It is beneficial for environmental protection and helps reduce urban pollution. Current urban pollution sources in our country. It is mainly caused by the large amount of coal burning and vehicle exhaust emissions. If a vehicle switches to burning liquefied natural gas, its harmful emissions are greatly reduced.