Liquefied air separation FAQ

The heat capacity of the Plate-fin switching heat exchanger is small, and the start-up time of the air separation plant is short, which is 30 ~ 36 H level; the start time of the air separation unit with stone cooler needs 48 ~ 60h. In terms of operation, master the essentials of operation: prevent moisture and carbon dioxide from being brought into the tower; strictly control the temperature difference between the cold end and the hot end; pay attention to the cooling of the main cooling; give full play to the refrigeration capacity of multiple expansion machines; reasonable allocation and utilization of cooling capacity, depending on the potential of the equipment itself to shorten the start-up time. Because of the large heat capacity of the stone cooler, it takes quite a long time to cool down to normal temperature after heating. The air of the turbine air compressor can be used to blow the stuffing to near normal temperature before starting the expansion machine, and hot air can ...

What should be paid attention to after using molecular sieve to purify air?

If the automatic adjustment system of the liquid level of the air cooling tower fails, it is easy to cause water accidents of the air separation tower, so the reliability of the self-adjustment system of the liquid level must be improved. Attention should be paid when installing: 1) the differential pressure transmitter should be installed on the same reference horizontal plane with the air cooling tower bottom; 2) the positive pressure and negative pressure diversion pipes should be introduced into the differential pressure transmitter on the same horizontal plane; 3) in winter, heating and antifreezing measures should be taken to prevent the static water in the diversion pipe from freezing. In order to improve its working stability and accuracy, a standard liquid level container can be installed in the negative pressure lead-out pipe. In the standard liquid level container, the height H of the liquid level is maintained constant by supplementary water and overflow pipe, which is g...

With the increasingly wide application of cryogenic liquid, in order to reduce material cost, improve storage efficiency, reduce equipment floor area, reduce energy consumption in the process of manufacturing, transportation and installation, and realize the green manufacturing concept of simultaneous development of safety production and energy saving, large-scale design has become the leading development direction of atmospheric pressure storage tank.   At present, the com...

Liquid appears too early in the liquid purifier, which means that the liquid purifier is connected too early. If the temperature condition of the switching heat exchanger has not been established, liquid will appear in the liquidator, which will result in the reduction of the flow gas of the switching heat exchanger due to the production of liquid, thus it is impossible to guarantee self-cleaning. Moreover, partial liquefaction of air will shrink the volume and reduce the pressure, thus increasing the positive flow air volume, which is not good for self-cleaning of switching heat exchanger. In addition, the backflow gas prematurely uses part of the cold energy for liquefaction, which will make the air in the switching heat exchanger can not be cooled to the working temperature as soon as possible, and even the temperature may rise. In this way, more carbon dioxide will be brought into the tower. Therefore, it is unfavorable for the liquid purifier to appear liquid too early. During ...

The forced valve of the Oxygen concentrator located separately on the upper and lower towers of the air separation unit fails, which causes changes in the tower

How to Determine the Leakage of the Main Condensate Evaporator in an Air Separation Plant

The liquid in the lower tower mainly comes from the liquid flowing from the first tower plate at the bottom. The liquid flowing down from the top Tower plate contacts with the air entering the tower on the first tower plate, part of the liquid evaporates, and the oxygen concentration in the liquid increases before flowing into the liquid kettle. However, its oxygen concentration is limited by the oxygen concentration (20.9% O2) of the air entering the tower, which is always lower than its equilibrium concentration. For example, when the pressure of the tower is 0.55 MPA, the oxygen concentration in the liquid which is balanced with the vapor containing 20.9% oxygen is 40.8%, while the actual oxygen concentration in the air should be lower than this value. Equilibrium concentration is related to pressure. With the increase of pressure, the equilibrium concentration decreases, and the oxygen concentration in liquid air also decreases. For example, when the pressure is 0.6MPa, the equi...

In the whole low-pressure air separation process, some are equipped with a liquid purifier, and some are equipped with two or even three liquidators, which make part of the air liquefied by the cold energy of polluted nitrogen, pure nitrogen or pure oxygen respectively. Some even combine the liquid purifier with liquid air and liquid nitrogen supercooler. The air flowing through the liquid purifier comes from the washing air of the lower tower or the low temperature air at the cold end of the switching heat exchanger. The function of the liquid purifier is related to the air separation process and start-up mode. Generally, it has the following functions: 1) in the stage of starting the hydrops, the liquidator plays the role of liquefied air and accumulating liquid. In some processes, the liquid purifier is not set up separately. For example, the 6500m 3/h air separation plant of the French liquefied air company makes the liquid air cooler, the sewage nitrogen cooler and the expansio...

The subcooler of the distillation tower of an air separation plant

Liquid gasification filling system consists of liquid storage tank, liquid pump and air purifier. In order to ensure the normal operation of the liquid pump, besides the reliability of the structure of the pump itself, the piping technology is also very critical. Improper piping, if it is light, it will cause "cavitation phenomenon" of the liquid pump, and the decrease of flow rate will lead to large mechanical loss of the pump; if it is serious, the filling pressure cannot be improved due to the serious gasification of the liquid in the pipe, the pump cannot work normally. Therefore, the following problems should be paid attention to when piping: 1) the base of the storage tank should be over 1m higher than the center of the liquid oxygen pump to ensure that the inlet of the pump has a higher static pressure (higher than the saturation pressure corresponding to the temperature ); 2) shorten the length of the pipeline from the storage tank to the pump inlet as much as possible to re...

What are the types of distillation tower plates in air separation equipment and what are their applications