Why should average pressure be performed when the molecular sieve adsorber is switched?

The liquid air level in the lower column is one of the core parameters of air separation distillation, and its fluctuation directly affects the product purity and system stability. The causes of liquid level fluctuation can be summarized into four categories: gas source disturbance, valve failure, instrument distortion and abnormal working conditions in the tower. 1、 Inlet gas volume and pressure fluctuation. This is the most common cause. Unstable exhaust pressure of air compressor and sudden reduction of gas volume during switching of molecular sieve adsorber will lead to fluctuation of air volume entering the tower. The lower tower is very sensitive to the change of gas volume, and the liquid level will fluctuate immediately. In addition, the abnormal working condition of the booster or the adjustment of the expander gas volume will also indirectly disturb the liquid level of the lower tower through the cooling capacity balance. 2、 Valve regulating system failure. The liquid air thr

In the operation of the air separation unit, the superheat of the expanded air sent to the upper column is a key parameter affecting the stability of distillation conditions and product purity. The fluctuation of superheat will directly change the gas-liquid load and mass transfer efficiency of the upper column, and then affect the distillation effect and energy consumption of the unit. If the superheat of the expanded air is too high, the gas entering the upper tower will carry a large amount of excess heat, which will significantly increase the gas phase temperature in the tower and aggravate the consumption of cooling capacity in the tower. This will lead to the decrease of reflux ratio in the distillation section of the upper column, insufficient gas-liquid two-phase contact, and poor mass transfer and heat transfer efficiency. At the same time, the increase of superheated gas will raise the rising gas flow in the tower and destroy the balance of distillation conditions, resulting