There are also trace acetylene and hydrocarbons in the air. Although they are adsorbed by the acetylene adsorber, the adsorption efficiency can only reach about 97%, and the rest will also threaten the safety production of the air separation unit. In order to eliminate the accumulated impurities such as water, carbon dioxide and acetylene, when the air separation unit runs for a certain period of time, it is necessary to stop the unit for heating and blowing.Air separation plant.The relationship between the refrigeration capacity of expander and various factors is as follows: the larger the expansion capacity is, the larger the total refrigeration capacity is. However, for the low-pressure air separation unit, the expansion air is directly sent to the upper column to participate in the distillation, too much expansion air will affect the distillation effect. This is what the separation process does not want.In order to avoid the increase of hydrocarbon concentration in liquid oxygen, according to the material balance, it is necessary to extract part of liquid oxygen from the main cooler and extract part of hydrocarbon from the main cooler. The minimum amount of liquid oxygen extracted is equal to 1% of the gas oxygen output, and then gasified separately.
Air separation plant.Liquid oxygen is a kind of low temperature and strong combustion supporting material. There is a large amount of liquid oxygen stored in the liquid oxygen tank. In addition to preventing leakage and low temperature burns, we should also be alert to the risk of explosion.In the air separation plant, the positive flow pressure air is cooled by the expanded low temperature air. If air wants to expand, it must be compressed first, and compression will consume energy. Air expansion can be achieved by throttling or expander expansion. However, the temperature drop of this expansion is limited.If the cooling water has been sprayed, the air is easy to carry water when it comes out of the cooling tower, so it is required to inflate the air in the tower first, and then start the water pump to supply water and spray after the pressure rises and the air flow is stable.In terms of manufacturing process, limited by the size of salt bath furnace, the maximum length of plate unit can only be 2.1m, and the section size is 750mm × 700mm ~ 1100mm × 1000mm. At present, with the development of technology, the longest plate unit can be 6m long.
Air separation plant.The quality of the liquefier can be judged by the difference between the temperature after the expander and the temperature of the waste nitrogen out of the liquefier. If the temperature rise is large, it means that the working condition is good; if the temperature rise is not obvious, the liquefier may be blocked and not play a role in liquefaction.If the air temperature in front of the expander increases, the unit refrigerating capacity will increase, but the expansion capacity will decrease, and the total refrigerating capacity will remain unchanged, that is, the temperature changes within the allowable range, which has little impact on the operation of the air separation unit. If the temperature of expansion air increases and the cooling capacity of expander decreases, the liquid air capacity will decrease and the liquid oxygen level will drop because the temperature before throttling also increases.Air separation plant.Machinery industry, mainly used for metal cutting and welding. Oxygen is used as combustion supporting agent of acetylene to produce high temperature flame and melt metal. In national defense industry, liquid oxygen is often used as the combustion supporting agent of rocket. The combustible material soaked in liquid oxygen has strong explosiveness and can be used to make liquid oxygen explosive. In addition, in the medical sector, oxygen is also an indispensable material for first aid and adjuvant treatment of patients. Therefore, oxygen production is an indispensable part of the national economy.
