Air separation plant selection and operation guide

Does a DEAR Biogas purification unit work with a piston compressor in reverse?

The air cooling tower is the core equipment of the air separation precooling system, which is mainly used to cool and wash the high-temperature compressed air discharged from the air compressor, provide qualified low-temperature gas source for subsequent molecular sieve purification and cold box rectification, and ensure the stable operation of the whole unit. The air cooling tower adopts the countercurrent packing heat exchange structure, the tower is filled with high-efficiency packing, and the top is equipped with a spray device and a wire mesh demister. During operation, the high-temperature compressed air at 80 to 100 ℃ discharged by the air compressor enters from the bottom of the tower and flows from bottom to top; The cooling water is the normal temperature make-up water and the low-temperature chilled water prepared by the water-cooling tower, which is sprayed from top to bottom from the tower top, and the air and water are fully contacted in reverse for heat exchange. Under t

Regulation of liquid nitrogen throttle valveThe opening of the liquid nitrogen throttle valve not only affects the reflux ratio of the upper tower, but also affects the reflux ratio of the lower tower. When the opening is increased, the reflux ratio of the upper tower increases, while the reflux ratio of the lower tower decreases, the purity of the nitrogen in the upper tower increases, and the purity of the oxygen enriched night sky in the lower tower increases. However, after the opening is over, the purity of the liquid nitrogen decreases, and the reduction of the reflux ratio of the upper tower is also detrimental to the improvement of the purity of the liquid oxygen. Therefore, an equilibrium point should be found for the opening of the liquid nitrogen throttle valve. We can generally use the purity difference between liquid nitrogen and gas nitrogen to judge whether the opening is appropriate. Generally, the purity of the sprayed liquid nitrogen is equal to that of the upper towe

In the field of air separation, entropy is the core thermodynamic parameter to measure the energy quality and irreversibility of the system, which directly determines the energy consumption level and operation efficiency of the unit. Entropy, with the symbol s, is essentially a measure of the degree of chaos and energy unavailability of a system, in kj/(kg ・ K). The second law of thermodynamics clearly states that the total entropy of an isolated system only increases but does not decrease, that is, the principle of entropy increase. The higher the entropy, the lower the energy quality, and the more difficult it is to convert into cold energy or useful work; The smaller the entropy, the more orderly the energy, and the more sufficient the available energy. The essence of air separation unit is the combination of cryogenic refrigeration and distillation separation, and the whole process is closely related to entropy. The ideal reversible process is an isentropic process, and the entropy

The full low pressure liquid air separation plant uses molecular sieve adsorption and purification, pressurized turbine expander refrigeration, regular packing on the tower, hydrogen-free hydrogen production, oxygen and nitrogen outside the compression process. Before the liquid air separation plant is sand stripped, a sand stripping plan and contingency measures are developed. Training for external construction teams, for all kinds of maintenance work tickets, etc. Firstly, open all the manhol...

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