With the progress of the times and the development of economy, people's life is getting better and better. However, in this context, China's social energy consumption is also in continuous consumption, serious damage to the environment. Therefore, energy saving and consumption reduction has become a key link in social development. Energy saving air separation unit is more and more favored by customers. The patent of ultra-low pressure discharge and energy saving possessed by DEAR air separation can reduce the energy consumption of unit by 5% - 15% and save a lot of operating costs of users. To provide energy-saving air separation unit for customers and help the industry to develop better is the direction that DEAR air separation has been striving for.