Hazards of Ammonia and Preventive Measures

Today, we will continue to introduce another common gas-ammonia.  

What is Ammonia? 

Ammonia is an inorganic compound with the chemical formula NH3. It is a colorless gas with a strong pungent odor. Ammonia is commonly used in the production of liquid nitrogen, ammonia water, nitric acid, ammonium salts, and amines. It can be synthesized directly from nitrogen and hydrogen. Ammonia can burn the mucous membranes of the skin, eyes, and respiratory organs. Inhalation of excessive ammonia can cause pulmonary edema and even death.  

Hazards of Ammonia

Ammonia is a toxic and flammable gas, mainly generated in industries such as animal husbandry, petrochemicals, printing and dyeing factories, and textiles. It is one of the hazardous chemicals with a relatively high accident rate in China. In recent years, ammonia leakage and explosion incidents have occurred frequently in China. Cold storage facilities, aquatic food factories, ammonia-equipment workshops, fertilizer plants, chemical plants, and tank farms are common areas for ammonia leakage. The hazards of ammonia leakage have caused serious losses to the lives and property of the country and the people, attracting widespread attention from the whole society.

Ammonia has strong corrosiveness and has a corrosive and irritating effect on the contacted skin tissues. After ammonia poisoning, the throat and mouth feel obvious irritation. When inhaled into the human body, ammonia easily enters the blood through the alveoli and combines with hemoglobin, destroying the oxygen-carrying function. Inhalation of a large amount of ammonia in a short period can cause symptoms such as tearing, sore throat, hoarseness, coughing, sputum with blood streaks, chest tightness, and difficulty in breathing. In severe cases, pulmonary edema may occur. When the ammonia concentration in the air reaches 500-700mg/m³, "lightning-like" death may occur. Inhalation of excessive ammonia, resulting in a high ammonia concentration in the blood, will cause cardiac arrest and respiratory arrest, endangering life.  

Hazards of Ammonia Leakage  

01 Easy Vaporization and Diffusion

When ammonia leaks, it changes from a liquid phase to a gas phase. Liquid ammonia will rapidly vaporize, and its volume will expand rapidly. The liquid ammonia that has not been vaporized in time atomizes in the vapor in the form of liquid droplets. In the initial stage of leakage, due to the partial evaporation of liquid ammonia, the density of the ammonia-vapor cloud is higher than that of air. The ammonia drifts with the wind, and it is easy to form a large-area poisoned area and a combustion and explosion area.  

02 Prone to Poisoning and Casualties

Ammonia is a toxic, irritating, and foul-smelling gas that is easy to volatilize. When ammonia leaks into the atmosphere and diffuses to a certain extent, it is likely to cause acute poisoning and burns. The maximum allowable concentration of ammonia in the air is 30mg/m³. When the ammonia content in the air reaches 0.5-0.6%, it can cause poisoning to personnel within 30 minutes. The main ways for ammonia to invade the human body are the skin, respiratory tract, and digestive tract.  

03 Prone to Combustion and Explosion 

Ammonia is not only a toxic gas but also a flammable gas. The auto-ignition point of ammonia is 651℃, the combustion value is 2.37-2.51J/m³, the critical temperature is 132.5℃, and the critical pressure is 11.4Mpa. When the ammonia content in the air reaches 11-14%, it can burn when encountering an open flame, and its flame is yellow-green. The presence of oil increases the combustion risk.  

04 Prone to Environmental Pollution

Ammonia can pollute the air. Under the action of wind, this toxic gas drifts with the wind, causing large-scale air pollution and harming humans and livestock. If a large amount of liquid ammonia leaks into rivers, lakes, reservoirs, and other water bodies, it will cause water pollution. In severe cases, the water in this water body cannot be used without treatment.  

05 Prone to Secondary Accidents

Ammonia is unstable. It decomposes when heated and has violent chemical reactions when in contact with fluorine, chlorine, etc. In case of high heat, the internal pressure of the container increases, and there is a risk of cracking and explosion.  

06 Difficult to Dispose of

Ammonia is stored in containers in a liquid state after being pressurized or cooled from a gaseous state. Due to different storage methods of liquid ammonia, different pressures in the containers, different leakage locations, and different sizes of cracks, high technical requirements and great difficulties are involved in taking measures such as plugging and transferring.  

Safety Solutions for Ammonia Leakage

Monitoring and prevention in places prone to ammonia leakage can effectively reduce the occurrence of accidents and disasters. It is crucial to install ammonia detectors in a timely manner. Since the density of ammonia gas is lower than that of air, the ammonia detector should be installed 0.5-2 meters above the leakage point, and the sensor part should face downward. Do not install the ammonia detector in the following locations:

• Places directly affected by steam and lampblack;

② Places with large air volume, such as air supply ports, exhaust fans, and doors;

③ Places with a lot of water vapor and water droplets (relative humidity: ≥90%);

④ Places with a temperature below -20℃ or above 50℃;

⑤Places with strong electromagnetism.  

Instrument Recommendation 

The ammonia detector of Chuang'an Electronics uses high-quality sensors, which can monitor in real-time whether the ammonia leakage concentration exceeds the standard and issue sound and light warnings in a timely manner. It can also be connected to external devices such as exhaust fans and solenoid valves to ensure the safety of ammonia-using places. In order to ensure the accuracy and reliability of monitoring in the liquid ammonia area, ammonia detectors must undergo regular calibration and maintenance. Calibration should be carried out according to the manufacturer's guidelines to ensure the accuracy and reliability of the measurement results of ammonia detectors under different environmental conditions.

Although ammonia is an important chemical raw material, its dual-nature requires us to be cautious during use. By using high-performance detection instruments, users can more effectively monitor and control the emission and distribution of ammonia to ensure the safety of the working and living environment.