In the air separation equipment, air volume is the core feed parameter of the rectifying column, and its size directly determines the operation stability, separation efficiency and product quality of the rectifying column. Reasonable control of air volume is the key to ensure smooth rectification process.
When the air volume is within the design range, the gas-liquid two-phase contact in the rectifying column is sufficient, the proportion of rising steam to falling liquid is balanced, the nitrogen, oxygen and other components can be effectively separated according to the design requirements, the product purity and output can meet the standard, the pressure, temperature and other parameters in the rectifying column are stable, and the energy consumption is at a reasonable level.
If the air volume is too large, it will exceed the processing capacity of the rectifying column, causing the rising steam flow rate in the column to be too fast, resulting in flooding and destroying the gas-liquid balance. At this time, the pressure in the column rises, the temperature fluctuates, the mass and heat transfer efficiency decreases, the product purity decreases, and the tray may be damaged, the equipment operating load and energy consumption increase, and the shutdown adjustment is required in serious cases.
When the air volume is too small, the rising steam is insufficient, the liquid-gas ratio is unbalanced, the mass transfer impetus in the column is weakened, the separation effect is worse, the product output is reduced, and the liquid leakage phenomenon is easy to occur, resulting in unstable operation of the rectification column, which will also increase the energy consumption per unit product and cannot meet the production demand.
To sum up, the air volume shall strictly match the design load of the rectifying column to avoid too large or too small, so as to ensure the efficient and stable operation of the rectifying column and realize the optimal balance between product quality and energy consumption.
