The reflux liquid from the upper tower of the distillation tower is throttled from the lower tower to the liquid air and liquid nitrogen from the upper tower, and the reflux ratio of the upper tower is also adjusted by the liquid nitrogen throttle valve. Because the pressure of the liquid air and liquid nitrogen passing through the throttle valve in the lower tower decreases, the corresponding saturation temperature also needs to be reduced. If the undercooling of the liquid is not enough, it will cause partial liquid gasification. The gasification rate will reduce the reflux ratio of the upper tower and affect the purity of nitrogen. So to improve the subcooling of liquid nitrogen in the liquid air passing through the throttle valve, a subcooler is generally installed to increase the subcooling of liquid nitrogen in the liquid air.
DEAR Air Separation improves the automation level of air separation equipment and achieves unmanned operation, which is in line with the current national policies and guidelines. The main technological innovation points of the unmanned project research and development of DEAR Air Separation include: (1) one click start of fully automatic process control process; (2) Remote monitoring technology based on the Internet of Things and cloud technology: (3) Expansion mechanism cold monitoring and cold volume control technology; (4) The uninterrupted supply technology of instrument gas for air separation equipment was previously manually switched; (5) Seamless switching technology for backup systems. The application of this technology will have a positive impact on the industry.
