Method for producing argon arc welding gas
Argon arc welding is a welding technology using argon as shielding gas.
Argon is a colorless and odorless inert gas. It accounts for 0.934% of the atmospheric volume and 1.288% by mass.
Most of the argon used in daily life is produced by air separation (air separation) devices.
The air separation device is an industrial equipment, which is used to separate various gases in the air to produce oxygen, nitrogen and other rare gases. The following figure is the flow chart of the air separation device.
The operation of the air separation unit is based on two basic principles:
1, throttling expansion. The adiabatic expansion process of fluid (gas or liquid) through porous plug (or throttle valve) at higher pressure to lower pressure. Throttle expansion will cause the oil temperature to drop. If the gas is throttled and expanded repeatedly, the temperature will decrease continuously, and finally the gas can be liquefied;
2. Fractionation. A method for separating several mixtures with different boiling points; Its essence is repeated distillation.
The working flow of air separation unit is as follows:
The compressed air from the air compressor is sent to the rectification tower after the impurities such as water, carbon dioxide and hydrocarbons are removed by the purifier, and part of the air is sent back to the rectification tower after expansion and refrigeration by the expander. After the rising steam in the distillation column exchanges heat with the falling liquid, high-purity nitrogen is obtained at the top of the tower and high-purity oxygen is obtained at the bottom of the tower by using the different boiling points of different gases. By properly controlling the temperature and increasing the number of distillation columns, the distillation column can obtain the effect that the upper part is argon and the lower part is nitrogen, or the upper part is oxygen and the lower part is argon.