Liquid nitrogen is an inert, colorless, odorless gas. It does not cause corrosion, non-combustible. This gas makes up most of the atmosphere (78.03% of the total). Although liquid nitrogen does not support combustion, it is inert, except when it is heated to very high temperatures, where it combines with some of the active metals, such as lithium, magnesium. Due to this compound, nitrides are formed. It can also interact with oxygen, resulting in the formation of nitrogen oxides, and in the combination of nitrogen with hydrogen in the presence of catalysts, ammonia.
Obtaining liquid nitrogen in an industrial environment
Liquid nitrogen and in the form of gas are obtained in the same way - from atmospheric air. In laboratories, it is obtained during the decomposition of ammonium nitrite. This is an exothermic reaction. That is why it passes with the release of 80 kcal (335 kJ) of energy. To obtain liquid nitrogen, cooling of the vessel is required, although heating is required to start the reaction. Also, molecular nitrogen in industry is obtained by fractional distillation of liquid air in the atmosphere. This method can also produce “atmospheric nitrogen”. All the methods by which they achieve the production of liquid nitrogen are aimed at creating a safe and clean product for industry, medicine and household chemicals.
Impact on human health
Although liquid nitrogen is not toxic and inert, it can provoke strangulation of a person, as it can displace oxygen in the air below the level necessary to maintain life. Excessive amounts of nitrogen can cause dizziness, nausea, vomiting, loss of consciousness, and death. Death can be the result of a loss of orientation and consciousness, which may impede self-evacuation from a contaminated area. With a low oxygen concentration, loss of consciousness and death can occur in a matter of seconds. Personnel, including rescuers, should not enter rooms without self-contained breathing apparatus or respirators if the oxygen concentration is below 19.5%.
If liquid nitrogen, then it is stored in special containers. This is necessary in order to protect others from the consequences of interaction with the element. Liquid nitrogen is stored at pressures up to 350 MPa in containers with volumes from 80 to 450 liters.
Liquid nitrogen - storage and use
Store and use this product only in rooms with good ventilation. It should not be stored in a closed space. Obtaining liquid nitrogen in the laboratory also involves special methods of its storage in containers. Cryogenic containers are equipped with special devices for relieving pressure and controlling internal pressure. Under normal conditions, they are safe. In no case should you turn on, remove or engage in any other interaction with a pressure relief device. Liquid nitrogen must not get on exposed parts of the body.
Containers in which liquid nitrogen is stored should only be used and stored in an upright position. Do not drop containers, do not store them on their sides. Also, vessels containing the substance cannot be disposed of on their own. If you have difficulty operating the container or valve, discontinue use immediately.
Personal Protective Equipment (PPE)
For safety reasons, you should definitely familiarize yourself with the properties of liquid nitrogen before starting work. It is necessary to protect the eyes and the most sensitive parts of the body from the vapor of cryogenic fluid. Obtaining liquid nitrogen in the laboratory and its use involves the availability of personal protective equipment. Must be: a protective mask or goggles, loose-fitting leather gloves, a long-sleeved shirt and pants without cuffs, you also need protective shoes, especially for those who handle containers. Respiratory organs must also be protected with special masks.