dc.contributor.advisor | Skogestad, Sigurd | |
dc.contributor.advisor | Susort, Nils Arne | |
dc.contributor.author | Vo, Phuong Ny Lillian Nguyen | |
dc.date.accessioned | 2023-09-27T17:21:38Z | |
dc.date.available | 2023-09-27T17:21:38Z | |
dc.date.issued | 2023 | |
dc.identifier | no.ntnu:inspera:146714212:35169578 | |
dc.identifier.uri | https://hdl.handle.net/11250/3092545 | |
dc.description | Full text not available | |
dc.description.abstract | I denne oppgaven ble det undersøkt om den nåværende temperaturreguleringen avDyneas formaldehyd sølvkatalysatorprosess kan forbedres. Den nåværende temperaturreguleringen har rom for forbedring, ettersom den strever i visse perioder. Oppgaven tar utgangspunkt i en eksisterende
matematisk dynamisk modell av prosessen, skrevet i MATLAB. Tre kontrollstrukturer ble implementert og studert: den nåværende tilbakekoblingen med valve position controller, tillegg
foroverkobling med input transformasjon og Nonlinear Model Predictive Control (NMPC).
Tilbakekoblings- og tillegg foroverkoblingsstrukturene ble implementert ved å kode dem inn
i modellen og det ble brukt modellens eksisterende løser, ode15s. NMPC ble implementert med
CasADI i MATLAB, hvor optimaliseringsproblemet ble løst ved hjelp av orthogonal collocation
metoden. Til slutt ble alle reguleringsstrukturene simulert, plottet og sammenlignet.
Resultatene viste at den foreslåtte tillegg foroverkoblingsstrukturen regulerte reaktortemperaturen
bedre enn den nåværende tilbakekoblingsstrukturen. Forbedringen skyldes strammere
regulering, som også forebygger metning og tap av regulering. NMPC viste seg å regulere
reaktortemperaturen enda bedre enn både tilbake- og tillegg foroverkobling, på grunn av dens
prediktive handling. Reguleringen var mer effektiv og reagerte tidligere, noe som førte til redusert
avvik i reaktortemperaturen fra settpunktet.
Den enkleste måten å forbedre temperaturreguleringen var å bruke de nye tuningparameterne
fra SIMC-regelen. Disse nye reguleringsinnstillingene førte til strammere regulering med
færre inngrep av sikkerhetstiltak. Denne endringen gir kanskje ikke den beste forbedringen, men
den kan på egen hånd betydelig styrke temperaturreguleringen. | |
dc.description.abstract | This thesis aimed to research if the current temperature control of Dynea’s formaldehyde silver
catalyst process could be improved. The current control has room for improvement as it
struggles at certain periods, especially during transient operation. The study started off with an
existing mathematical dynamic model of the process, written in MATLAB. Three control structures
were implemented and studied: the current feedback control with valve position controller,
added feedforward control with input transformation and Nonlinear Model Predictive Control
(NMPC).
The feedback and added feedforward control structures were implemented by coding them
on top of the model and used with the existing solver, ode15s. NMPC was implemented with
CasADI in MATLAB, where the optimization problem was solved using the orthogonal collocation
method. Finally, all control structures were simulated, plotted and compared.
The results showed that the proposed added feedforward structure was able to control the
reactor temperature better than the existing feedback control. This improvement was due to
tighter control, which also prevents saturation and loss of control. Furthermore, NMPC appeared
to control the reactor temperature even better than both the feedback and added feedforward
structures, due to its predictive action. The control was more effective and reacted earlier, resulting
in reduced deviation in the reactor temperature from the setpoint.
The simplest way to improve the temperature control was to use the new tuning parameters
from the SIMC-rule. These new control settings resulted in tighter control with fewer interventions
of safety measures. While this change may not yield the best improvement, it could
significantly boost the temperature control on its own. | |
dc.language | eng | |
dc.publisher | NTNU | |
dc.title | Control of formaldehyde silver catalyst reactor system | |
dc.type | Master thesis | |