Properties of liquid ammonia and its hazards

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This post was last edited by huanghong on 2021-2-3 at 17:21. Liquid ammonia is ammonia in a liquefied state, also known as anhydrous ammonia; it is a colorless liquid that is corrosive and volatile. It is formed when gaseous ammonia is pressurized to 0.7–0.8 MPa, with a large amount of heat being released in the process; conversely, a large amount of heat is absorbed when liquid ammonia evaporates. Due to its excellent thermodynamic properties, liquid ammonia is widely used as a refrigerant in cooling systems. Liquid ammonia is toxic, and ammonia gas has a strong, irritating odor that is harmful to the human body. When the ammonia concentration in the air reaches 0.5–0.6% (by volume), a person can be poisoned after staying there for half an hour; concentrations above 0.6–1% may lead to death. At room temperature, ammonia is a flammable gas, but it is difficult to ignite. It can be ignited at 11–14%, and an explosion will occur if exposed to an open flame at 16–25% (the explosive range is 16%–25%), with 17% being the concentration most prone to causing ignition. The concentration at which the maximum explosion pressure is achieved is 22.5%. Ammonia leaks not only pollute the atmosphere but also cause significant damage to plants and animals. Liquid ammonia splashing on human skin can also cause frostbite. Liquid ammonia is widely used in industry; it is corrosive and volatile, which results in a relatively high incidence of chemical accidents. In recent years, accidents involving ammonia-related enterprises have occurred frequently. For example, on June 3, 2013, a particularly severe fire broke out at Jilin Baoyuanfeng Poultry Industry Co., Ltd. in Dehui City, Jilin Province, resulting in 121 deaths and 76 injuries ； On August 31, 2013, an ammonia leak occurred at Shanghai Wengpai Refrigeration Industry Co., Ltd., resulting in 15 deaths, 7 serious injuries, and 18 minor injuries.