The main tower of the air separation tower and the crude argon tower are organically connected through the position of the argon fraction extraction port, the liquid air feeding method, and the feeding port position.
When extracting argon fractions, it is beneficial for the separation of oxygen and nitrogen, improving the distillation conditions of the upper tower, increasing the purity of oxygen and nitrogen products, and increasing the extraction rate of oxygen. After extracting argon fraction, it has a significant impact on the working conditions from the liquid air inlet of the main tower to the fraction extraction port. Since the rising Vapor quality decreases and the reflux ratio increases, more trays are needed to ensure the purity of liquid oxygen. In addition, during this period, due to the extraction of 30% to 40% of the rising steam, the flow rate also decreases accordingly. If no measures are taken, it is easy to cause liquid leakage and reduce the distillation effect. Therefore, it is necessary to reduce the mesh area appropriately, and some adopt cross arrangement of bubble cap trays and mesh plates.
In addition, during the production of argon, it is necessary to extract a portion of the liquid air and liquid nitrogen from the main tower as a cold source. At the same time, due to the increase in equipment, the cold loss also increases accordingly. Therefore, it is required that the device produce more cooling capacity to maintain cooling balance. For medium pressure devices, it is necessary to increase the high pressure pressure; For a fully low-pressure device, the expansion can only be increased, which affects the distillation conditions of the upper tower and reduces the average nitrogen purity. Therefore, when the amount of expansion air entering the tower is limited and the cooling capacity is insufficient, the argon fraction can only be reduced.
