In the distillation operation of air separation plant, product purity and energy consumption are the core indicators of mutual restriction. Excessive pursuit of high purity will lead to energy waste, and one-sided energy saving will easily lead to the purity not reaching the standard. Only by fine parameter regulation and system collaborative optimization, can the two-way balance between purity stability and energy saving and consumption reduction be achieved.
Optimizing distillation conditions is the core of balancing energy efficiency. In daily operation, it is necessary to abandon the bad habits of conservative operation, strictly control the purity margin on the premise of meeting the production indicators, stabilize the purity of oxygen and nitrogen products within the reasonable range of the lower limit of the contract, and eliminate excess purity and energy consumption. Focus on dynamic control of reflux ratio, maintain 1.1 to 1.25 times the economic reflux ratio, reduce reflux slightly when purity is surplus, and fine tune the increment in critical state to avoid increasing equipment load due to reflux redundancy. At the same time, the principle of "lower tower pressure stabilization and upper tower low pressure" is followed to reduce the upper tower operating pressure within the allowable range of the equipment and reduce the compression energy consumption and cooling capacity loss.
Strengthen the collaborative adaptation of cooling capacity and front-end system to further reduce invalid energy consumption. Accurately regulate the expansion air volume, match the stable working condition of the main cooling liquid level, and ensure the maximization of refrigeration efficiency. Strictly control the heat exchange temperature difference of the main heat exchanger, fully recover the waste nitrogen and residual cooling, and reduce the cold loss of the system. The synchronous linkage air compressor and purification system match the gas flow into the tower as required, eliminate excessive air intake and venting energy consumption, optimize the molecular sieve regeneration process, stabilize the air flow into the tower and reduce the fluctuation of distillation conditions.
The contradiction between purity and energy consumption can be effectively resolved through normalized and refined operation and maintenance and dynamic parameter optimization. On the basis of ensuring stable product quality and safe and stable production, the unit energy consumption of air separation equipment can be continuously reduced and the economic benefits of enterprise production can be improved.
