ISSN: 1410-2331 Abdul Wahid, Multiloop Control Design 67 MULTI-LOOP CONTROL DESIGN IN MULTIVARIABLE (2X2) CONTINUOUS STIRRED TANK REACTOR Abdul Wahid, William Andreas Hambali Department of Chemical Engineering, Faculty of Engineering, University of Indonesia Kampus Baru UI Depok – 16424, Indonesia E-mail: wahid@che.ui.ac.id, w_a5291@yahoo.com Abstrak -- Dalam penelitian ini, desain dan tuning multi-loop untuk multivariabel (2x2) CSTR dilakukan untuk mencapai kinerja kontrol CSTR yang optimal. Penelitian ini menggunakan reaktor Model Bequette dan software MATLAB dan diharapkan dapat mengatasi gangguan dalam reaktor sehingga sistem reaktor mampu menstabilkan dengan cepat meskipun gangguan. Dalam penelitian ini, desain dibuat menggunakan pendekatan multi loop, bersama dengan PI controller sebagai langkah berikutnya. Kemudian, BLT dan metode penyetelan auto-tune digunakan dalam PI controller dan diberi gangguan dari metode find tuning. Performa kontroler kemudian dibandingkan. Hasil dari penelitian ini menunjukkan bahwa dalam hal penolakan gangguan, BLT lebih baik dari auto-tune berdasarkan perbandingan antara kedua performa kontroler. Untuk IAE dalam kasus suhu, BLT adalah 30% lebih baik dari auto-tune, tapi hampir sama untuk kasus konsentrasi. Untuk settling time untuk kasus konsentrasi, BLT adalah 30% lebih baik dari auto-tune, dan untuk kasus suhu, BLT adalah 18% lebih baik dari auto-tune. Untuk waktu kenaikan untuk kasus konsentrasi dan temperatur, BLT adalah 30% lebih baik dari auto-tune. Kata kunci : Pendekatan Multi-loop, Bequette reactor, Performa Pengendali Abstract -- With this study, the design and tuning of multi-loop for multivariable (2x2) CSTR will be made in order to achieve optimum CSTR control performance. This study used Bequette model reactor and MATLAB software and is expected to be able to cope with disturbances in the reactor so that the reactor system is able to stabilize quickly despite the distractions. In this study, the design will be made using multi-loop approach, along with PI controller as the next step. Then, BLT and auto-tune tuning method will be used in PI controller and given disturbances to both of tuning method. The controller performances are then compared. Results of the study are then analyzed for discussions and conclusions. Results from this study have shown that in terms of disturbance rejection, BLT is better than auto-tune based on comparison between both of controller performances. For IAE for the case of temperature, BLT is 30% better than auto-tune, but it is almost the same for the case of concentration. For settling time for the case of concentration, BLT is 30% better than auto-tune, and for the case of temperature, BLT is 18% better than auto-tune. For rise time for the case of concentration and temperature, BLT is 30% better than auto-tune. Keywors: Multi-loop approach, Bequette reactor, Controller performances. 1. INTRODUCTION CSTR reactor is used in big industries that require processes that can’t be stopped because the production has to remain continuous such as oil refineries and so on (Altmann, 2005). Usually in this type of reactor, the reaction occurs always not linear and has very high complexity. This kind of reaction is difficult to control by conventional method because it has multiple steady states in this equipment. Also reactor of this kind involves a multivariable system that’s why even proportional-Integral (PI) control system may not give good results for multivariable systems. This kind of condition also led to frequent interruptions to the CSTR reactor that would make the resulting product does not fit with what is desired (Farouq and Jayakummar, 2009) (Wu, 2000). That’s also why it’s necessary to have the control system that can work well in nonlinear and multivariable system. The approach will be used here is the multi-loop approach. Although it has been decades, there are already many successful multi-loop strategies have been used and proven to be a good approach thus it continue to be used. Because of its use of simple algorithms, it’s ease to be understanding by plant operating personnel, which is the result of its simple control structure. Since each controller will use only one measured controlled variable and adjust only one manipulated variable, the actions