The safety requirements of liquid oxygen are more stringent than that of oxygen, in addition to the general safety requirements of oxygen, it is also necessary to prevent the chemical explosion of acetylene accumulation and precipitation in liquid oxygen, to prevent the violent evaporation of liquid resulting in physical explosion, to prevent the damage of low-temperature liquid equipment and frostbite, etc., and to ensure the safety of liquid oxygen storage tanks



The safety technical requirements of nitrogen machine manufacturers for nitrogen machine liquid oxygen storage tanks are as follows.



The liquid oxygen storage tank is generally placed in a safe place near the air separation equipment, away from the fire source, heat source and fuel source, and the safety distance between railways, roads and buildings is the same as the requirements of the oxygen storage tank.

(2) The liquid oxygen storage tank in the form of powder vacuum insulation, the inner cylinder is made of stainless steel with good low temperature performance, the outer cylinder is made of carbon steel, the interlayer is filled with pearlitic sand insulation material, and the vacuum is pumped to 1.36 ~ 6.8Pa to achieve the insulation effect, in order to prevent the drastic evaporation of liquid oxygen and overpressure. In use, the vacuum degree of the sandwich should be regularly monitored, and any abnormality should be handled immediately.

③ pearlite sand insulated liquid oxygen storage tank, the inner tube is high-strength alloy aluminum, the outer tube is carbon steel, the sandwich is filled with enough thick pearlite insulation material, the bottom with a certain thickness of foam glass brick or slag wool insulation, to prevent severe evaporation of liquid oxygen, overpressure. Its basis can be referred to the basis of air separation equipment, to waterproof and anti-freezing, to adapt to the requirements of low temperature conditions.

④ The inner wall of the liquid oxygen storage tank should be strictly degreased, and degreasing agents such as carbon tetrachloride are generally used to defat. Liquid oxygen storage tanks should be strictly welded, flaw detection and inspection, and the technical requirements are the same as that of oxygen storage tanks. Because its inner cylinder is stainless steel or high-strength alloy aluminum, it is generally welded by argon arc welding.

(5) The inner and outer cylinders of the liquid oxygen storage tank should be tested for strength and air tightness. Its practices, requirements, standards, etc., similar to oxygen storage tanks, due to low temperatures, so the requirements are more stringent. •

The use of liquid oxygen storage tank is strictly prohibited overpressure, liquid oxygen storage tank because it is the storage of low-temperature liquid, in order to reduce cold loss and prevent severe evaporation overpressure by heat, powder vacuum insulated storage tank, must often monitor the sandwich vacuum and tank pressure, if necessary, vacuum to improve the vacuum. For the powder (pearlite sand) adiabatic liquid oxygen storage tank, the interlayer pearlite sand should be filled, filled, and filled with dry nitrogen and dry pearlite sand to improve the adiabatic effect.

In the liquid oxygen storage tank, due to the continuous evaporation of liquid oxygen, the acetylene concentration may increase, resulting in accumulation and precipitation. In order to prevent explosions, the acetylene content in liquid oxygen is analyzed once a week and controlled below 0.1X10_6. When the standard is exceeded, the air separation device should continuously transport liquid oxygen to the liquid oxygen storage tank to dilute the acetylene concentration, and start the liquid oxygen pump and carburizer to transport outward to eliminate the danger. If the liquid oxygen in the liquid oxygen storage tank can be often transported outward for use, this hidden danger can be eradicated.

⑧ Prevent liquid oxygen leakage of frozen facilities and frostbitten people, and maintain positive pressure in the liquid oxygen storage tank. Prevent wet air inhalation, causing freezing blockage. Before the liquid oxygen storage tank is used, dry nitrogen should be blown to remove moisture, and the exhaust dew point should not be higher than 45°c.

⑨ Oxygen has magnetic sensitivity, under the action of discharge, it is easy to form a very high chemical activity of smelly oxygen, which is the excitation energy of detonation, so in the liquid oxygen tank radius of 30m do not allow open fire or electric spark, must use explosion-proof electrical appliances.

⑩ Liquid oxygen storage tank is not allowed to fill the tank liquid storage, the maximum filling volume is 95% of the geometric volume or according to the equipment manual operation, because liquid oxygen is liquid, its compressibility is very small, when the full tank liquid storage, the temperature rises, the volume expansion, will cause the liquid oxygen storage tank rupture accident.