FAQ

Sieve tray is one of the most widely used trays in air separation columns. Its main structure is that there are evenly distributed small holes with spacing of 2.1 ~ 3.25 mm and diameter of 0.8 ~ 0.13 mm on the tray. During the operation, the steam bubbling up through the liquid layer through the sieve hole, and the liquid on the tray can only flow in a fixed direction because it is held by the steam. The advantages of sieve tray column are simple manufacture and high efficiency. The disadvantages are that liquid may leak through the sieve hole when the load is too low.

The air in nature is not absolutely dry, and a certain amount of gaseous water vapor is always mixed inside, which is a conventional part of air. Under normal pressure and normal temperature, water vapor is evenly dispersed in the air and will not condense into liquid water, so we cannot directly observe water. In the air separation operation, the air is first compressed by the air compressor. After the air is compressed, the volume is greatly reduced, and the density of water vapor in unit space increases sharply. At the same time, the saturated water content of air will change with the increase of pressure. Under high pressure, the upper limit of water vapor contained in air tends to be fixed. When the water vapor content exceeds the saturation value corresponding to the pressure, the air will reach the supersaturated state, which has the basis of water precipitation. The air compression process will generate a lot of heat, and the high temperature environment can temporarily improve

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

The start-up and operation of liquid air separation plants requires the operator to be familiar with the performance and operation of the systems, machines and equipment in the liquid air separation plants, to be familiar with the process flow diagram of the liquid air separation plants, and to master the operation rules and operating characteristics of the liquid air separation plants. In order to ensure the purity of the product, the operator must be able to improve the quality of the product ...

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