【Weekly Topic】Week 28, 2011——How do air separation units achieve the transition between oxygen and nitrogen operating modes?
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If there is an excess of total oxygen, it is desired to produce more liquid oxygen; or if there is an excess of nitrogen, it is desired to produce more liquid nitrogen. Please explain briefly your process for switching between oxygen and nitrogen operation modes
If there’s an abundance of both oxygen and nitrogen, then add a liquefaction unit. Am I sitting on the sofa?
1. In the external compression process, as LS mentioned, the liquefaction unit can solve this problem. 2 If there is no liquefaction device during internal compression, and if oxygen or nitrogen is available in sufficient quantities, it’s fine to keep the liquid oxygen and liquid nitrogen valves fully open even if the expansion volume remains unchanged.
Reply to 3# Kitayama: If the internal compression is not specified as having special requirements during contract negotiation, it’s difficult to change the operating conditions. To make significant changes to the operating conditions, additional equipment such as heat exchangers is needed. Otherwise, it is not possible to produce more liquid either, as it is restricted by the equipment.
Each set of equipment is designed with a certain amount of design margin; when the total amounts of oxygen and nitrogen are sufficient, it is possible to increase the volume of liquid within a certain range. No matter how it is adjusted, it must comply with the principles of mass balance and energy balance. Whether it is internal compression or external compression, increasing the volume of liquid requires a comprehensive adjustment process. With the air volume and cooling capacity remaining constant, the operating conditions of the upper and lower towers are adjusted, as well as the amount of liquid oxygen or liquid nitrogen extracted. The valves feeding into the upper tower are fine-tuned to ensure stability in the system’s operating conditions.
I’d like to ask the experts here: are there many liquefaction units available in China? ? ? ? ? ? ? ? ? ?