Thread Content
LNG is short for liquefied natural gas; by cooling natural gas to around -162°C at normal pressure, it can be turned into a liquid, which is liquefied natural gas (LNG). It is formed by purifying natural gas (by removing water, hydrocarbons, and acidic gases), and then using processes such as throttling, expansion, and the application of external cooling sources to convert methane into a liquid state. The volume of LNG is about 1/620 of its gaseous volume. Natural gas liquefaction technology includes natural gas pretreatment, the liquefaction and storage of natural gas, the gasification of liquefied natural gas and the recovery of its cooling capacity, as well as safety technologies. LNG utilization is a capital-intensive, chain-like systems project with closely interconnected upstream and downstream components, consisting of six stages: natural gas extraction, natural gas liquefaction, LNG transportation, LNG reception and gasification, natural gas transmission pipelines, and end-users of natural gas. Since natural gas shrinks by 620 times after liquefaction, it is easy to transport economically and reliably. Replacing deep-sea and underground long-distance pipelines with LNG carriers can save substantial investment in risky pipelines and reduce transportation costs. Based on economic considerations related to gas transportation, pipeline transport of gas is most cost-effective over distances of around 3,000 km; beyond 3,500 km, shipping liquefied natural gas becomes more advantageous, offering better economic benefits compared to pipeline transport. LNG plays a significant role in balancing global natural gas supply; it can address energy shortages, ensuring a steady supply for those without access to gas or those whose gas reserves are running low. For regions that already have access to gas, it can help with peak load management and supply supplementation. It not only diversifies the sources of natural gas but also holds great economic value. LNG has many advantages over underground gas storage for peak shaving in city gasification. For example: its location selection is not restricted by geographical location, geological structure, distance, capacity, etc.; it requires less land, has low costs, a short construction period, and is easy to maintain. In cities without gas fields or salt cavern aquifers, it is difficult to build underground gas storage facilities, and therefore LNG is needed for peak shaving. This technology is already fairly mature abroad; for example, LNG is used for peak shaving in the United States, the United Kingdom, and parts of Canada. Our country is also introducing this technology. Liquefied natural gas contains a large amount of low-temperature energy; at 1 atmosphere pressure, it can release approximately 879 KJ/kg of energy in its gaseous state at room temperature. Its cold energy can be utilized for power generation via cryogenic methods, air separation, ultra-low temperature freezers, the production of dry ice, and the freezing of food products. Since the LNG plant removes impurities from the gas during preprocessing, the flue gases emitted when LNG is burned as fuel contain very low levels of SO2 and NOx. Therefore, it is known as a clean energy source; it is widely used for power generation, urban household gas, and industrial gas, reducing air pollution and contributing to the coordinated development of the economy and the environment.