Long tube and short tube condensing evaporators are tubular type. The copper tubes are arranged vertically according to concentric circles or equilateral triangles. Brass tube sheets are installed at the top and bottom. The tubes and tube sheets are soldered with tin. The long tube is for liquid oxygen evaporation, and the short tube is for gas nitrogen condensation. The length of long tube is about 3M. The refrigeration capacity of air separation plant includes expander refrigeration capacity and throttling refrigeration capacity. After the expansion air of medium pressure air separation unit enters the lower tower for liquefaction, it also enters the upper tower through liquid throttling, while the expansion air of low pressure air separation unit no longer passes through throttle valve. So, is it only the part of gas (or liquid) passing through the throttle valve that produces throttling effect and refrigeration capacity? In fact, this is not the case.
If the explosion of air separation plant is serious, the whole equipment will be damaged and even casualties will be caused; The slight explosion occurred in the local position, which reduced the purity of oxygen products and could not maintain normal production. Explosions are all related to the accumulation of flammable substances hydrocarbons in liquid oxygen. For the medium pressure air separation plant, the low temperature air from the main heat exchanger enters the lower tower by throttling expansion, so as to ensure that the air entering the tower has a certain moisture content. For the expansion of cryogenic liquid, the energy loss of liquid throttling is small, and there is no significant difference between expander expansion and throttling expansion. The structure and operation of throttling valve are much simpler than expander. Therefore, throttling expansion is adopted when the liquid from lower tower expands to upper tower.
Generally, the hydrogenation amount of air separation plant manufacturer should be increased by 1% excess hydrogen according to the hydrogen amount required for complete reaction of hydrogen and oxygen. The purpose is to make the oxygen in the crude argon react fully and further improve the purity of the refined argon. According to the calculated amount of hydrogenation and start hydrogenation, the process should be slow“ "Cooling capacity" is a kind of idiom in the field of refrigeration. Because in order to get a lower temperature than the environment, it depends on the power consumption of refrigeration. That is to say, there is a price to be paid to remove heat from cold objects. Because its temperature is lower than the ambient temperature, it has the ability to spontaneously absorb heat from the environment. The air separation unit with switching purification process refers to the self removal of water and carbon dioxide in the channel of switching plate fin heat exchanger (or cold accumulator) by switching the switching valve. In the air separation unit with switching purification process, circulation or intermediate extraction is often used to reduce the temperature difference at the cold end of plate fin heat exchanger (or cold accumulator);
Medium pressure blow off: after high pressure blow off, close the main inlet valve of high pressure air and open the blow off valve of oil-water separator. Install high pressure and medium pressure gauges, install and close throttle-1 valve. Close the blow-1 and blow-2 valves, then open the main inlet valve of high pressure air and close the blow off valve. For the purification process of molecular sieve adsorption, the adsorption capacity of molecular sieve is related to temperature. The lower the temperature is, the larger the adsorption capacity is. For a certain size of adsorber, the working cycle can be long, or for a certain adsorption cycle, the designed adsorber volume can be small, so it is also required to pre cool the air to the lowest possible temperature. In the nitrogen water precooler, the cooling capacity of nitrogen is fully recovered and utilized to cool the air.
