Advantages (1) safe and reliable The ignition point of LNG is 230 ℃ higher than that of gasoline and higher than that of diesel; The explosion limit of LNG is 2.5 ~ 4.7 times higher than that of gasoline; The relative density of LNG is about 0.43 and that of gasoline is about 0.7. It is lighter than air. Even if there is a slight leakage, it will volatilize and diffuse rapidly, so as not to spontaneous combustion and explosion or form the limit concentration of explosion in case of fire. Therefore, LNG is a safe energy. (2) clean and environmental protection According to the sampling analysis and comparison, LNG, as an automobile fuel, reduces the comprehensive emission by about 85% compared with gasoline and diesel, including 97% reduction in CO emission, 70% ~ 80% reduction in HC, 30% ~ 40% reduction in NOx, 90% reduction in CO2, 40% reduction in particulate emission and 40% reduction in noise. In addition, it is free of carcinogens such as lead and benzene, basically free of sulfide, and has excellent environmental protection performance. Therefore, LNG is a clean energy. (3) economical and efficient After liquefaction, the volume of LNG is reduced to about 1 / 625 of that of gaseous natural gas, and its storage cost is only 1 / 70 ~ 1 / 6 of that of gaseous natural gas. It has the advantages of low investment, less land occupation and high storage efficiency. In addition, the cooling capacity carried by LNG can be partially recycled. (4) flexible and convenient LNG can transport a large amount of natural gas to any user who is difficult to reach through the pipeline through a special tank car or ship, which not only saves investment compared with the underground gas transmission pipeline, but also is convenient, reliable, low risk and strong adaptability. According to statistics, more than 100 LNG peak shaving devices have been built and put into operation in the United States, Japan and Europe. It not only saves land, capital and construction period compared with the construction of ground high-pressure gas storage tanks and underground gas storage, but also is convenient, flexible and not limited by geological conditions. For countries with insufficient gas sources, importing LNG is the most convenient and economical way to solve their gas supply. In addition, LNG can be easily vaporized with seawater.