A case study of Frontrol System on TEREOS' plant and results.
We asked some questions to Luciano Rangel, the engineer responsible for the implementation of the advanced process control in two ethanol and sugar plants in Brazil, about the application of Frontrol System. Initially his short Résumé is presented.
Name: Luciano Rangel
Company: Tereos
Position in the Company: Process Specialist
Short Résumé: Luciano Rangel has earned many degrees throughout his life. Some of them are his Bachelor's Degree in Electrical Engineering (UFTM), Computer Engineering (UNIUBE), System Analysis and Development (IFTM), and Mathematics (UNESP Rio Preto). He also holds an MBA in Project Management (FGV) and a Masters in Advanced Process Control. He has been working with industrial automation at Tereos since 2015. As a process specialist, he has already implemented solutions involving plant information management systems (PIMS), advanced process control (APC), and real-time optimization systems (RTO). He is currently working on projects related to ​​digital transformation/issues and to the Industry 4.0.
What is your opinion about the application of Frontrol System to control the density of ethanol distillation columns?
We know that more than 90% of our industrial process is controlled through PID type controllers which have good performace combined with its simplicity. However, some parts of the process are often difficult to achieve good efficiency just using traditional PID control. Variability in results may come from processes with nonlinear characteristics, with high dead time, multiple inputs and multiple outputs, equations that are difficult to estimate, or with wide operating ranges.
In distillation columns, all these items can be present, and that makes it unfeasible to use PID controllers. It is necessary to go to the top layer and use alternatives such as fuzzy control to operate the process more efficiently. That is why we chose to use fuzzy logic to control density, wine flow, column level and pressure.
Regarding the deployment of Frontrol System, what did you notice in terms of infrastructure needs and deployment time?
After the infrastructure implementation and the creation of the logics are finalized by the plant automation specialist, the whole implementation lasts for 1 week and then another 2 weeks for tuning control parameters and training the operators. The involvement of the operators and the managers is essential, as at the end they are the ones who will use the tool.
Would it be possible to measure the reduction of the process variability and the steam savings after the implementation of Frontrol System?
The use of advanced control in the distillation columns brought positive results with important reduction in the process variability and higher ethanol production.
Data was evaluated between 09/01/2020 and 11/20/2020 with the advanced control applied to the columns at different times. The error was calculated by the percentage difference between the set point and the process variable. It can be seen in the figure below that the control error is smaller when the advanced control system is enabled.
As shown in the figure below, the average control error was also 91.2% lower when the Frontrol System was enabled.
Ethanol production was 9.2% higher when the Frontrol System was running in the plant, as shown below.
It also contributed to reducing the number of operator interventions in the process. The reduction was from 28 interventions per hour to 0 interventions.
Describe your experience with the application of the Frontrol System to control the pH of dosed broth.
Frontrol System was also applied to pH control of sugar dosed broth in the Tereos sugar mills UICA and UIM, in São Paulo, Brazil
Goal: Reduced variability of the dosed broth pH.
The proposed method allows the integration of the control loops, predicting disturbances and resulting in a stable and efficient process.
An important variability reduction was obtained for the dosed broth pH in the Tereos plants of UICA and UIM, as shown in the figure below.
What is your opinion regarding the contribution of Frontrol System to the implementation stage of the industry 4.0 process at Tereos?
The industry 4.0 program projects bring returns on one of the three pillars: cost reduction, experience gain, and safety. With advanced control, we have seen a reduction in process variability that results in operating closer to the restrictions. That is, we are able to make more use of the asset capacity, thus reducing the cost of utilities such as steam and water, which brings a very high added value to the operation. We consider that every plant must have advanced control and we are looking forward to implementing that in all of them.