Rapid variable load optimizing control method for oxygen and nitrogen rectification outer compression air separation plant

Abstract

The invention discloses a rapid variable load optimizing control method for an oxygen and nitrogen rectification outer compression air separation plant. A two-layer system structure in which large-range technology optimization and nonlinear predictive control are combined is adopted in the rapid variable load optimizing control method. A technology optimization calculation (RTO) module and a model predictive control (MPC) module are included. The RTO module calculates the optimal steady-state value of the process variable related to the load change according to the variable load requirement of the device and through the air separation low-temperature deep cooling technology optimizing calculation and sends the optimal steady-state value to the multi-variable predictive control MPC module; and the MPC module gradually pushes the device to the optimal steady-state work point obtained through calculation of the RTO module on the premise that equipment constraint is not violated and the product quality is guaranteed. The method solves the problem about nonlinearity in the variable load process, the problem about operation coupling, the problem about time optimum and the problem about energy consumption optimization, fluctuation of key variables of equipment can be more effectively reduced, and variable load operation is more rapidly and stably achieved.

Description

technical field [0001] The invention relates to a fast variable load optimization control method for oxygen and nitrogen rectification external compression air separation equipment, which belongs to the technical field of air separation equipment automation engineering. Background technique [0002] Raw material air is inhaled from the suction port, dust and other mechanical impurities are removed through the self-cleaning air filter, and the filtered air is compressed to about 0.602MPa in the air turbine compressor. After being pre-cooled by the air cooling tower, the cooling water enters the cooling tower in sections, the lower section is the circulating cooling water, and the upper section is the water cooled by the water cooling tower chiller. The air passes through the air cooling tower from bottom to top, and is cleaned while being cooled. After the air is cooled by the air cooling tower, the temperature drops to ~17°C, and then enters the switched molecular sieve pur...

AI Technical Summary

Problems solved by technology

In the absence of automatic load changing technology, the production load is often unable to be adjusted in time, and the excess oxygen can only be emptied, resulting in a high amount of oxygen release, resulting in a large amount of energy consumption and economic losses

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