Analysis on the nature, use and leakage hazard of liquid ammonia

1、 The nature of liquid ammonia liquid ammonia, also known as anhydrous ammonia, is a colorless liquid with a strong irritant odor As an important chemical raw material, ammonia is usually pressurized or cooled to obtain liquid ammonia for the convenience of transportation and storage Liquid ammonia is widely used in industry, which is corrosive and volatile, so its chemical accident rate is very high Ammonia gas, with molecular formula NH3, is a toxic gas of class 2.3, which has strong toxicity and flammability Ammonia gas, colorless at normal temperature and pressure, has a strong irritant odor At 20 ℃ and 891kpa, it can liquefy and release a lot of heat When the temperature of liquid ammonia changes, the coefficient of volume change is very large Soluble in water, ethanol and hemi Molecular weight is 17.03, melting point is - 77.7 ℃, boiling point is - 33.5 ℃, gas density is 0.7708g/l, relative vapor density (air = 1) is 0.59, relative density (water = 1) is 0.7 (- 33 ℃), critical pressure is 11.40mpa, critical temperature is 132.5 ℃, saturated vapor pressure is 1013kpa (26 ℃), explosion limit is 15% - 30.2% (volume ratio), self ignition temperature is 630 ℃, larger explosion pressure 0.580MPa 。 2、 The use of liquid ammonia is widely used in the production of chemical fertilizers, such as nitric acid, urea, and other raw materials for medicine and pesticides Because liquid ammonia changes into gas ammonia after gasification, which can absorb a lot of heat, it is known as "refrigerant" At the same time, liquid ammonia has a certain bactericidal effect, so in poultry breeding industry, it is used for sterilization and cooling Liquid ammonia can also be used in rocket, daodan propellant, and mercerization of textiles At the same time, because of its special chemical properties, it is well used in semiconductor, metallurgical industry and chemical industry 3、 Hazards of leakage of liquid ammonia 1 Danger of combustion and explosion: extremely flammable, able to form explosive mixture with air, causing combustion and explosion in case of open fire and high heat; 2 Active reaction: violent chemical reaction will occur when contacting with fluorine, chlorine, etc.; 3 Health hazards: strong stimulation and corrosion to eyes and respiratory mucosa Acute ammonia poisoning causes eye and respiratory tract irritation symptoms, bronchitis and peribronchitis, pneumonia, and toxic pulmonary edema may occur in patients with severe poisoning High concentration of ammonia can cause reflex respiration and cardiac arrest Can cause eye and skin burns 4、 Prevention measures for leakage of liquid ammonia 1 Provide sufficient local exhaust and comprehensive ventilation in the workplace where liquid ammonia is used, keep away from fire and heat source, and prohibit smoking in the workplace; 2 Ammonia leakage detection alarm shall be set in the workshop and storage place where ammonia is produced and used Explosion proof ventilation equipment and system shall be used At least one set of positive pressure air respirator, long tube gas mask and rubber gloves shall be equipped When the ammonia concentration in the workplace exceeds the standard, the operator shall wear filter type anti-virus area Frostbite shall be prevented when liquid ammonia may be contacted Ammonia leakage detection alarm is a professional instrument to detect ammonia concentration When the ammonia concentration in the atmosphere reaches the preset value, the alarm will immediately send out an audible and visual alarm or linkage exhaust device, so as to remind people to take emergency rescue measures to ensure the production safety of the plant area