Large air separation FAQ

1.The purpose of purging is to purge the welding slag and dirt left in the pipeline and container. 2.The principle of purging is doing the outside columnfirstly,and the inside column after. The purging should be carried out one pipeline by one. 3.When purging the system, the filter core on the equipment inlet pipe should be removed. 4.When purging the pipe outside the cold box, all the valves connected with the cold box should be disconnected to prevent dirt from entering the valve and column. 5.The purging of each system should be repeated for many times. The purging time shall not be less than 4 hours. 6.To check whether the purging is complete, wet white filter paper or white cloth shouldbe used to placeat the outlet of purging. After 5 minutes, it is qualified if it is clean and free of obvious mechanical impurities.

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...

When the amount of processing air is reduced, the rising steam and reflux liquid in the upper column will be reduced, but the reflux ratio will not change. Therefore, the reduction of processing air in a small range will not affect the purity of oxygen and nitrogen, and the reduction of processing air volume will help to reduce the pressure of the upper and lower columns. However, according to the material balance, the production of oxygen and nitrogen will naturally decrease when the amount of processing air is reduced. If the amount of processing air is too small, there will be leakage on the tray. If the heat and mass exchange of the leaked liquid is not sufficient, the purity of oxygen and nitrogen will be greatly affected, and even the normal production can not be realized. Therefore, the minimum allowable load of distillation column is generally specified.

Air separation unit is a kind of unit that takes air as raw material, transforms air into liquid by low temperature cryogenic method which compresses and circulates air, and then gradually separates oxygen, nitrogen, argon and other inert gases from liquid air by distillation. At present, the air separation unit produced in China has many forms and types. There are unit for the production of gaseous oxygen and nitrogen, as well as unit for the production of liquid oxygen and nitrogen. However, there are four types of basic processes: high pressure, medium pressure and low pressure, and full low pressure process. The production scale of air separation unit in China has developed from the original oxygen generator which can only produce 20m³/ h (oxygen) to the current large-scale air production capacity of 20000 m³/ h, 30000 m³/ h and 50000 m³/ h (oxygen). The air separation unit can be divided into 5 basic systems in terms of process 1. Impurity purification system: the mechani

The air separation column mainly includes main heat exchanger, liquefier, distillation column, condensing evaporator, etc. The main heat exchanger, condensing evaporator and liquefier are plate type of heat exchangers. It is a new type of all aluminum metal composite partition heat exchanger. The average temperature difference is small, and the heat exchange efficiency is as high as 98-99%. Distillation column is the unit of air separation. The types of column unit are classified according to the internal parts. The sieve plate column with sieve plate, the bubble cap column with bubble cap plate, and the packed column with packing material. The sieve plate is widely used in air separation distillation column because of its simple structure, easy manufacture and high efficiency. Packed column is mainly used for distillation column with diameter less than 0.8m and height less than 7m. Bubble column is seldom used because of its complicated structure and difficult manufacture. Turbine

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: