Nitrogen blockage prevention and control method for argon generation system of air separation device

Abstract

The invention discloses a nitrogen blockage prevention and control method for an argon generation system of an air separation device. The nitrogen blockage prevention and control method comprises the steps that the measured values of the important indicators including the argon content of an argon fraction, the argon fraction temperature and the argon content at the top of a crude argon column II are selected as manipulated variables, wherein the argon content of the argon fraction and the argon fraction temperature serve as the first line of defense for monitoring whether nitrogen blockage occurs or not, and the argon content at the top of the crude argon column II serves as the second line of defense; the gaseous oxygen taking-out quantity, the upper column pure liquid nitrogen backflow quantity and the crude argon extraction quantity are selected as operating variables; the optimal control increment of each operating variable is calculated through a predictive control algorithm, wherein the gaseous oxygen taking-out control increment and the upper column pure liquid nitrogen backflow control increment are used for adjusting the argon fraction argon content and the argon fraction temperature of a main column, and the crude argon extraction control increment is used for adjusting the argon content at the top of crude argon column II; and in addition, a feedforward control function is further designed for a controller, the switching pressure-increasing process, affecting the argon fraction argon content and the argon fraction temperature, of a molecular sieve purifier is used as an event variable and introduced into the disturbance variable of the controller, and feedforward information is provided for the two operating variables including the gaseous oxygen taking-out quantity and the pure liquid nitrogen backflow quantity.

Description

technical field [0001] The invention relates to a nitrogen plug prevention and control method for an argon production system of an air separation unit, and belongs to the technical field of air separation control engineering. Background technique [0002] Argon is the most abundant noble gas in the air. figure 1 A process for producing argon by air separation is given. The raw material air is rectified in the low-pressure column of the main column, and the product nitrogen will be obtained at the top of the column, and the product oxygen will be obtained at the bottom of the column, and an argon enrichment zone will be formed in the stripping section. The extraction of argon is to extract a certain amount of gas-phase argon fraction from the middle and lower part of the low-pressure tower, and enter the crude argon tower for rectification. Due to the large number of plates in the crude argon column, the height of the column is not conducive to installation and maintenance o...

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Problems solved by technology

[0008] In order to overcome the deficiencies of the existing air separation argon system nitrogen plug prevention and control scheme that cannot adapt to the dynamic characteristics of air separation argon operation, strong nonlinearity and coupling between loops, the present invention provides a real-time online monitoring and adjustment Changes in oxygen, argon, and nitrogen content in the argon production system, realizing online real-time monitoring and control of the nitrogen plug in the air separation unit, a nitrogen plug prevention and control method for the argon production system of the air separation unit

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