METHOD AND EQUIPMENT FOR LOW TEMPERATURE SEPARATION OF AIR

PROBLEM TO BE SOLVED: To provide a method and equipment for low temperature separation of air which enable attainment of stable operations in a full load state and an insufficient load state, while maintaining a sufficient pressure difference for a transfer fraction between a high- pressure tower and a low-pressure tower or between the high-pressure tower and an evaporation chamber of a condenser in the top of a crude argon tower even when the structural height of a fractionator is large due to the use of a low-pressure-loss filling, and which enable avoidance of useless consumption of gas resources as relaxation gas, in particular, on the occasion. SOLUTION: Source air 1 is introduced into a fractionator 3 and transfer fractions 6 and 7 of concentration ρ are taken out as liquids from reservoirs in the fractionator and sent to separate processes 5 and 23 after expansion 14, 14a and 18. A liquid level in the reservoirs 24 and 16 is under a first pressure p1 at a first level h1, while fractions after the expansion are supplied to the separate processes 5 and 23 under a second pressure p2(p2h1). The difference Δp=p1-p2 between the two pressures is smaller than the liquid-column Static pressure (phydr=p.g.[h2-h1]) of the fractions between the first and second levels. The expansion is executed within the range wherein Δp is large enough to supply the fractions to the separate processes 5 and 23 and in such a manner that bubbles generated in the expansion may reduce the concentration of the fractions.