Large air separation FAQ

The start-up of the air separation plant includes three stages: cooling, hydrops and purification. For a certain equipment, the start-up time is roughly certain. As for the low-pressure air separation equipment, there is no room to adjust the pressure of the air compressor. Generally, it depends on two expansion machines working at the same time to increase the refrigerating capacity in the start-up stage and shorten the start-up time. Even so, according to the maximum refrigeration capacity and the cooling required by cooling and Hydrops of the device, the start-up time of the device needs to be more than 36 hours. Large air separation plants are generally equipped with liquid oxygen storage tanks as emergency standby oxygen. If necessary, can liquid oxygen be filled into the tower to shorten the start-up time of the air separation plant? Theoretically, it is completely possible. For example, if filling 1M3 liquid oxygen into the main cooling, it is equivalent to providing 0.47 × 1...

When the working condition of the air separation plant is stable, the cooling capacity of the unit keeps balance with the cooling capacity consumption, and the temperature, pressure, liquid level and other parameters of each part in the unit no longer change with time. The main cooling is the bond connecting the upper tower and the lower tower. The rising nitrogen from the lower tower is heated and condensed in the main cooling, and the reflux liquid oxygen from the upper tower is absorbed and evaporated in the main cooling. When the amount of recirculation liquid is equal to the evaporation, the liquid level remains unchanged. When the processed air enters the tower, it has certain "moisture content", that is, a small part of it is liquid. Most of the air will be liquefied in the main cooling. As for the low-pressure air separation equipment, the air going into the tower is composed of the air at the cold end of the main heat exchanger and the air passing through the liquid purifie...

The process of extracting neon and helium from the air separation plant is divided into three steps: the first step is to produce crude neon and helium; the second step is to produce pure neon and helium mixture; the third step is to separate neon and helium, and get pure neon, pure helium products. The purpose of crude neon and helium preparation is to remove nitrogen from raw materials and make them concentrated. Because the boiling points of nitrogen, neon and helium differ greatly, which is over 50 K, it can be separated in the condenser or auxiliary tower by using low pressure liquid nitrogen as cold source, make the nitrogen in the feed gas of neon and helium with the pressure of the lower tower condense, and get the content of neon and helium about 1% ~ 3%, the rest is the mixture of crude neon and helium of nitrogen, and then enter the pure neon and helium preparation process. Some processes of crude neon and helium need to go through hydrogen removal and nitrogen removal. T...

Molecular sieve is a kind of crystal of siovenate, which has many micropores with uniform aperture size. The skeleton is usually negatively charged, and there is a cation in the pore channel that balances the negative charge of the skeleton. The earliest molecular sieve found was natural zeolite. People found that the ore exploited near the crater would produce bubbles after heating, so it was called zeolite. In 1930s, United Carbide Company of the United States firstly artificially synthesized 4A and 13X molecular sieves, and applied the molecular sieves as desicides in petrochemical industry. Later United Carbon Company successively discovered Y-type molecular sieve and applied it to the catalytic field, replacing the previous application of silicon-aluminum balls, which increased the gasoline production rate by more than 15%. At that time, the world's annual crude oil consumption was 400 million tons, and generate economic benefits of 8 billion dollars. Later, a series of molecul...

The technical requirements of molecular sieve purifier include: 1. the manufacture, inspection and acceptance of the molecular sieve adsorption cylinder should comply with "pressure vessel safety technology supervision regulations" and CB 150-1998 "steel pressure vessel", it should also comply with the provisions of "The design and manufacturing technical conditions of adsorber for large and medium-sized air separation plant. 2. the molecular sieve adsorption cylinder A, B class welding joints for 100% ray detection, quality should meet the JB/t4730-2005 "pressure equipment nondestructive testing" n level requirements, the penetration test of the weld seam of the socket and the barrel head meets the level I requirement of JB/t4730-2005. 3. After the equipment is manufactured, conduct the air pressure test with 0.69MPa (gauge pressure), and then conduct the air tightness test with 0.6MPa (gauge pressure). The test method is in accordance with gb150-1998 and relevant provisions. 4....

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The air pressure test on site is mainly to check the air tightness of the air separation plant. The following problems should be paid attention to during Pressure Test: 1) oxygen is strictly forbidden to be used as the pressure test air source; 2) clean and oil-free pressure test air source should be applied to the oil-free equipment without degreasing after pressure test; 3) the pressure gauge used for pressure test should be checked and sealed before using. Before the pressure test, check carefully whether the pressure gauge valve has been opened; 4) during the pressure test, do not knock the pressure test container with a hammer; 5) during the pressure test, do not dismantle or tighten the screws; 6) when using nitrogen cylinder or air source with higher pressure level to inflate and test pressure to the container with lower pressure, pressure reducing valve should be installed, and direct inflating is strictly prohibited. 7) pressure test after the inflation reaches the specifie...

Oxygen (O2) is a colorless, odorless and odorless gas. The molecular weight is 32. The relative density is 1.429 (Air = 1 ). The melting point is-218.4 ℃. Boiling point is-183℃. Can be liquefied and solidified. Liquid oxygen is sky blue. Slightly soluble in water. It is not very active at normal temperature, and it is not easy to have effects on many substances; but it is very active at high temperature, and can be directly combined with various elements. Fuel Fuel. Oxygen is the substance on which living creatures depend. It is widely used in industrial production. Acetylene-oxygen flame is used for metal welding and cutting. In metallurgical industry, oxygen is used for iron and steel smelting, steel rolling and non-ferrous metal refining. Oxygen is widely used in medical treatment and deep work. Modern industry adopts the method of cooling separation to produce oxygen. According to the pressure of compressed air in its production process, it can be divided into four types: High p...

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