Applicant hierarchical fuzzy controller for concentration control of simulated moving bed

Chaofan Xie,Yang-Jie Tang

doi:10.1038/s41598-021-97134-5

Chaofan Xie, Yang-Jie Tang

Open Access

https://doi.org/10.1038/s41598-021-97134-5

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Abstract

Simulated moving bed (SMB) is a kind of continuous process which can increase the efficiency of adsorbents in the adsorbent bed. It contains several sectors of flow rate, the switching time of valves and many other possible influencing variables, moreover, these parameters are highly sensitive, so it is very difficult to achieve precise prediction and control. Model predictive control and PID controller are often used in industrial system. Model predictive control needs a lot of accurate industry experience data, and PID controller depends on the selection of control parameters. Therefore, SMB needs an intelligent controller to bypass those complex mechanisms and parameter adjustment processes. This paper we propose the hierarchical fuzzy controller fuzzy controller which is applied to the SMB system to observe the final concentration. Compared with the PID and MPC controller, it is found that the hierarchical fuzzy controller can control good without knowing the system parameters too accurately.

Highlights

Simulated moving bed (SMB) is a kind of continuous process which can increase the efficiency of adsorbents in the adsorbent bed
Defines the output control parameter flow rate QI, QII, QIII during the SMB operation process, three independent fuzzy controllers act on three regions, for the input of the third region, we use the weighted average of the input errors of the first region and the second region, taking the single pole fuzzification value where the center value is (NB,NS,ZE,PS,PB) = {0.15, 0.1, 0, − 0.1, − 0.15} for QI (NB,NS,ZE,PS,PB) = {0.006, 0.004, 0, − 0.004, − 0.006} for QII . (NB, NS, ZE, PS, PB) = {0.08, 0.05, 0, − 0.05, − 0.08} for QIII
The SMB process is digitalized by using centered difference method, in this way, the concentration data of materials changing with time and space can be generated, and the data trend charts with different parameters can be obtained

Summary

Introduction

Simulated moving bed (SMB) is a kind of continuous process which can increase the efficiency of adsorbents in the adsorbent bed. Csijec t (t) = Cij−1(ln−1, t), other where Cf the feed stream concentration and Q is the flow rate in each section, use formula (8–10), can get the boundary numerate condition: Cij(w+1, k)+Cij(w+1, k+1) = Cij(w−1, k + 1)+Cij(w − 1, k)

Results

Conclusion