The regulation of the cooling capacity of the air separation unit is a complex and delicate process, involving several operational aspects and parameter adjustments.
Appropriate closing of the oxygen and nitrogen delivery valves can increase the low and medium pressure, thus reducing the cooling capacity. Turbine expander air inlet adjustment adjustable nozzle, the opening is small, the refrigeration capacity is reduced. If the main cooling liquid level increases, the yield and purity of the product gas oxygen, argon distillate in the oxygen content decreases, so that the distillation conditions deteriorate, then the expansion air volume should be reduced. Open the bottom of the heat exchanger blow-off valve, you can exclude some of the overcooled liquefied air, which helps to regulate the amount of cold. When there is liquid oxygen level in the main cooling, the throttle valve of the main tower startup line should be fully closed to regulate the cooling capacity. Proper control of the air compressor cooling water can increase the temperature of the high-pressure air into the tower, which affects the cooling capacity. During the cooling phase, the cooling capacity of the expander should be maximized. As the temperature in the tower decreases, the expansion volume should be gradually increased to regulate the working condition of the expander and maintain the maximum cooling capacity. Appropriate discharge of some liquid oxygen can consume part of the cooling capacity. However, it should be noted that the liquid oxygen level should not be lower than a certain value to avoid affecting the normal operation of the air separation unit.
In the process of adjusting the cooling capacity, it should be kept stable and avoid drastic fluctuation. Keep the pressure inside the air separation unit stable and avoid over-pressure or low-pressure operation. Closely monitor the purity of the product oxygen to ensure that it meets the production requirements.
