Compared with the original equipment, what are the technical improvements of the new small air separation plant?

Since 1990s, some mature advanced technologies of oxygen generation have also been applied in small air separation plants, which have reduced cold loss, improved efficiency, reduced operating pressure and saved energy, simplifies the operation. Mainly in the following aspects:
1) replacing the tube-wound heat exchanger with the Plate-fin Heat Exchanger results in improved heat transfer performance, reduced the consumption of metal materials, and also made the temperature difference at the hot end of the heat exchanger from the original 5 ~ 7℃ to 2 ~ At 3℃, the cooling loss of incomplete heat exchange is reduced, which can reduce the working pressure of the unit. After the condensation evaporator adopts the narrow channel Plate-fin Heat Exchanger, the heat transfer temperature difference of the main cooling can be reduced from 2.5 ℃ to 1.25 ℃, and the condensation pressure of the lower tower can be reduced by 0.04MPa, which is beneficial to reduce the discharge pressure of the air compressor;
2) adopt direct cooling air precooling system. In order to improve the adsorption performance of the molecular sieve, before the air enters the purifier, the refrigerating machine provides cold energy to precool the air. In order to improve the heat exchange effect, the chilled agent is adopted to conduct heat exchange with air directly in the evaporator, which simplifies the cooling system and makes it easy to operate;
3) adopt long-period adsorber group. Extending the switching time of the adsorber from 8 h to 24 h greatly simplifies the operation. However, the filling amount of the adsorbents is less than doubled, which also reduces the consumption of recycled gas and power;
4) try to use structured packing structure (upper tower) or mixed structure of copper (circulation tower type distillation tower) and aluminum (heat exchanger, pipeline) in the distillation column. But we need to solve the welding problem of copper and aluminum;
5) adopt vertical non-lubricating air compressor and oxygen compressor, which can greatly prolong the life of vulnerable parts and improve the mechanical performance;
6) use gas bearing turbine expansion unit to replace piston expansion machine to improve the efficiency of expansion machine.