Large air separation FAQ

When the amount of treated air increases, the rising steam in the distillation column will increase, and the amount of liquid to be condensed in the main cooler will increase accordingly, so it has no effect on the reflux ratio in the column. The purity of oxygen and nitrogen remained unchanged in a certain range with the increase of gas volume, and the output increased proportionally with the increase of gas volume. However, with the increase of the amount of condensate in the main cooler, the heat load of the main cooler increases. When the heat transfer area is insufficient, the temperature difference of the main cooler will inevitably expand, and the pressure of the lower column will increase accordingly. At the same time, with the increase of gas velocity in the column, the amount of downflow liquid increases, and the liquid layer on the tray thickens, which increases the resistance of the tray and the pressure of the upper and lower columns. This will adversely affect the sepa

In the main column of the air separation column, the distribution of argon varies with the position of the liquid air inlet. With the increase of liquid air inlet position, the maximum concentration of argon enrichment zone in the stripping section also increases, and the nitrogen content in the distillate can be reduced. However, the argon content in the downstream also increases. In order to ensure the purity of oxygen, more trays are needed under the extraction port of argon fraction. Therefore, in the case of producing argon, the position of liquid air supply E1 should be appropriately increased compared with the case of not producing argon. Some unit is equipped with two liquid air inlet positions to meet the conditions of argon production and non argon production respectively. In the production of argon, in order to improve the extraction rate of argon, the content of argon in oxygen and nitrogen must be reduced. When the content of argon in exhaust nitrogen is more than 0.3%

There are 10 ways to transilluminate the welding seam of air separation unit, which are suitable for different occasions. Single wall is the most commonly used transilluminating method, but when the radiation source or film cannot enter the inside small diameter vessel and pipeline, double wall transilluminating method is adopted. The selection of transillumination method should consider all factors synthetically. For example, according to the principle of selecting the transillumination method which is beneficial and improves the sensitivity, single wall transillumination should be selected as far as possible. According to the principle which is conducive to the detection of corresponding defects, the outside radiation source is preferred for the detection of cracks on the inner wall of the container.

If the temperature after the expander of the air separation unit is too low, it should find out the cause of the low temperature and take measures to increase the temperature after the expander. If the low temperature of expander is caused by liquid air in front of expander, appropriate measures should be taken to reduce the liquid air level of lower column. If it is caused by other reasons, the more effective method is generally throttling in front of the expander. Throttling will not increase the temperature in front of the expander, but throttling will reduce the pressure in front of the expander, so the pressure difference between the front and the back of the expander will be reduced, the expander will do less work and the temperature will be reduced, so the temperature at the after of the expander can be increased.

1.In the process of preparation and implementation of hoisting construction, the safety and quality assurance system must ensure the normal operation,to ensure that the hoisting project meets the requirements of safety and quality. Before hoisting, safety and quality inspection must be carried out, and it must comply with the code forLifting construction of chemical engineering construction (HG20201-2000) and other regulations and specifications. 2.The crane performance shall meet the requirements of hoisting process, and the alarm and hydraulic system must be reliable. 3.Strictly implement the provisions of the technical documents attached to the crane. 4.The hoisting schedule of auxiliary crane should match that of main crane. 5.The hook deflection angle shall not be greater than 3°. 6.It is forbidden to drag the unitdirectly on the ground with crane. 7.Before unithoisting, trial hoisting shall be carried out. The clear hoisting distance and the foundation change at

1.The cold box foundation is divided into frame type and non frame type. The levelness of top surface of frame type frame shall not exceed 1 / 1000. All sections of the frame shall be placed vertically. All bottom plates of non frame type cold box shall be kept at the same level, and the levelness shall not exceed 1 / 1000.   2.When installing the cold box plate, the adjacent two sides can beassembled into a whole piece or angle type on the ground. The length error of each diagonal line a...

After a long-term operation of the air separation plant, the components in the cryogenic equipment and pipelines in the distillation system will be blocked due to ice or mechanical powder, which will increase the resistance of the fractionator. When the air separation plant has been in normal operation for about 2 years, the fractionator system should be heated and thawed to remove these deposits. When the molecular sieve adsorber and the main heat exchanger have water inflow or other faults, it is also necessary to stop and heat up. In general, the following methods will be used for heating and thawing.

After a long-term operation of the air separation plant, the components in the low-temperature equipment and pipelines of the distillation system will be blocked due to the internal precipitation of icing or mechanical powder, which will increase the resistance of the fractionating column. Therefore, after the normal operation of the air separation plant for about 2 years, the fractionating column system should be heated and thawed to remove these sediments. When the molecular sieve adsorber and the main heat exchanger have water or other faults, they must also be stopped for heating. The following describes several heating and thawing operation methods: