Experiences with operator training simulators in a refinery A review from the refinery process automation expert: Practical steps to make OTS a success story

Special guest editor: Tibor Szabo
Experiences with operator training simulators in a refinery

The appearance and gradual dissemination of training simulators will make simulation-based vocational training increasingly important. This critical role no longer prevails only in aircraft simulations, but it is also becoming more and more widespread in the operation of power plants, oil refineries, nuclear power stations and other industrial process technologies.
First principle simulation software applications used nowadays are enabled to provide not just fundamental training but are also capable of generating complex drills and exercises encompassing the broadest spectrum of operations.
They contribute to significant learning time reduction and greatly increase operators’ skills in terms of control. At the same time, they can substantially boost operational reliability and reduce process risks next to improved efficiency and profitability. Optimal and energy efficient operation is one of the most pressing tasks in a refinery. In this regard, one can state that High Fidelity priority simulation software available nowadays (e.g. Hysys®, UniSim®, PRO/II) also truly do have this kind of potential.
Today’s high level advanced process automation environment makes it possible to purchase certain simulation training tools or tool systems with a broad spectrum and capacities. Such tools may constitute an asset particularly for companies which have high expectations and aim for efficient operational priorities. Such simulation training tools not only make it possible to conduct high standard simulation based training courses, but they also serve as a fundamental guarantee for them. They may be used – in conjunction with written training materials, instructions, available documentation and process diagrams – to ensure that plant control personnel are confident, dedicated and well skilled. 

In 2005 MOL launched the first Operator Training Simulator (OTS) Project. The first two UniSim based training simulators were implemented in 2007 (at Duna Refinery’s Fluid Catalytic Cracking and Reforming units). Now there are nine High Fidelity simulators in operation at Duna Refinery in Százhalombatta. These systems were installed in five training rooms, each close to their respective technologies. It is a very important criterion for training attendants to be close to their workplaces thus making possible for them to practice using simulators at any time their work allows. Another experience was (again, as expected) that high standard training can only be attained through whole plant simulation. If process control, plant startup, plant shutdown or even operational interruption situations are exercised with plant modelling, it can significantly boost operator capabilities and deepen their know-how about technological processes.

Training sessions and experiences

In order to provide the reader with accurate and comprehensive impression, it is important to present the fundamental components of training system whose existence, function and operation are indispensable conditions for efficient and high standard training. 

A well-prepared specialist with high standard technological knowledge is one of the fundamental guarantees for the operation and use of Operator Training Simulators.

The full-time instructor can be considered as the system’s owner. There are 5 full-time OTS instructors employed at Duna Refinery. Their main duties include compiling training exercises and developing them to the level of efficient training tasks. In addition, they are also responsible for preparing, organising and conducting training sessions. Continuous use of the system contributes to refining of the implemented model, making it even more accurate (with the participation of the maintenance group). One of the full-time instructors’ critical tasks, which at once also carries the greatest responsibility is the implementation and evaluation of yearly OTS examinations for every operator and shift manager. In addition, they also make recommendations and remarks to improve the efficiency of the system operation. Using specified KPIs (key performance indexes) they draft yearly reports about the system’s operability and accuracy, efficiency of training sessions, as well as the maintenance process.


Scheduling of training sessions is an important action. Without scheduling operating the system would be incomprehensible for the users, and it would be impossible to keep track of utilisation indicators. A preliminary schedule (drafted by the instructors) is created every six months. It contains all information that guarantees full utilisation of the system and conducting of training sessions. They use 6 different colour codes to identify the activities and provide useful framework for utilisation of the systems.


When an exercise is created on a conceptual level, in many cases it is not enough just to upload it to the training simulator and drill it. Instead, operators and shift managers should receive these tasks in a detailed form.

This is necessary because education, rather than testing is the most important goal of the training sessions. In other words, knowledge transfer should deepen skills and lay the appropriate foundations for a highly efficient operator staff pool.

This is why it is important to generate more complicated, complex exercises in written form as well, and make them available at the instrument room and on MOL’s intranet site to everyone interested.


An examination period follows exercises and training sessions. According to refinery practice, these are linked to on-the-job training session examinations. OTS system provides, an automatic evaluation software report (which is part of the OTS system) and on the other written feedback that assesses examinations in a complex way. 

Besides electronic evaluation, a written assessment form is also used. It delivers a much more complex, comprehensive and broad scope performance assessment. This comprehensive impression is important because it allows making an inference how incidents occurring during real operation would be managed. Categories evaluated in writing include:

  • Information collection (shift handover / takeover procedure) 
  • Accurate and unequivocal identification of the situation that arose during the exercise
  • Communication during the execution of the exercise 
  • Abiding by HSE considerations, safety engineering requirements, operating requirements
  • Efficiency, accuracy, diligence of interventions effected during the exercise,
  • Execution of task, elimination of simulated event, the occasional restoring of normal operational conditions.

These two forms of evaluation guarantee the accurate, unbiased and comprehensive percentage score that serves as the basis for the various employees’ performance assessment,
influencing their future salary and bonuses.


Nature and efficiency of maintenance is the alpha and the omega of our work, they strongly influence the usefulness of OTS system. The properly functioning, efficient and successful system can be sustained on the long run only by appropriate maintenance and support thus improving or at least maintaining the usefulness of OTS system. 

This is why we continuously track every activity related to maintenance and repair that is conducted on any of the OTS systems. Currently all completed operations are entered in the appropriate ‘drawer’ of the electronic shift log after they are completed. At the same time, such entries also entail approvals by the instructor.


A full day workshop is organised every year affording us an excellent opportunity to shed light on jobs from the preceding year, completed tasks, evaluations, and everything else that happened in the OTS framework. Representatives from every plant that has an OTS, from other refineries in MOL Group, and Duna Refinery’s management usually attend the event. The presentations, discussion and sometimes debates at the event all contribute significantly to the success of OTS.

Training process

Training is a complex process made up of many stages. The exercise has to correspond perfectly to situations that occur during real plant operations. Another critically important part of the various exercises is that the task should never be too simple or overly complicated. They always need to be aligned with the capabilities of personnel and should carry extra content that can be the key to improving and deepening staff’s skills.

Since the appearance of the simulators, substantial emphasis has been placed on which subjects ought to be exercised during various training sessions. At Duna Refinery we continuously strive to leverage the opportunities the model provides, and the knowledge that has been accumulated in the life of the instructors and plants. Based on these assets, we are in the process of developing a system with the main elements already in-use since go-live.

However, continuous improvement is required in order to broaden operators’ skills and create interesting, efficient exercises that also provoke thinking.

The training method called ‘WHOM’, an acronym based on the first letters of its four components, is the next stop of this development.


What if

This part of the ‘WHOM’ training sessions is about exercises that occur very rarely at the given plant or have not occurred at all. They include the types of incidents that have been discussed on multiple occasions in theory, but never happened before. However, they may occur at any time. Compiling such exercises is the instructor’s task. Recommendations from operators and shift managers are welcomed. The following exercises can be listed here:

  • Redundant pump stop
  • Sequence of transmitters failures
  • Heard but not experienced unit failures, etc.


This is the category that assumes the execution of exercises which occurred at the given plant some time before. These are the typical exercises for which scenarios are drafted. This is important because there were colleagues, who did not go through the incident at the real plant. These colleagues need to be well informed about processes, fully understand the series of actions that were executed, and they have to learn about the possibly incorrect interventions. The following exercises can be listed here:

  • Unit upset
  • Failures
  • Mistreat
  • Instrument failure
  • Pump upset
  • Compressor upset, etc.


This is the training category, for which improvement and perfection is currently under way. Energy consumption optimisation and production efficiency improvement are among the most important requirements for refineries. OTS offers an excellent opportunity for operators to improve their related knowledge. Using training simulators optimisation exercises can be repeated at any time and training attendees will be able to leverage know-how acquired during simulation training in real operational circumstances. Furthermore, they will be able to learn how to abide by the ever more stringent energy efficiency parameters and stricter quality requirements. As it was mentioned, the introduction of this kind of practice is currently in progress. For the sake of the greatest possible complexity and efficiency of the system, a few modifications had been made. 

They impact Honeywell’s UniSim® operation and DCS (distributed control system) interfaces. Allow for the traceability of optimal function, efficient operation or energy efficient intervention, the display of some parameters (e.g. density, composition) found in the model on the HMI (Human-Machine Interface) is indispensable.
In this way attendees in training can see parameter and quality changes they cause through their interventions in efficient and less efficient operations of the various processes.
The transparency of such parameters represent a challenge to the burnt out operator staff practices – ‘Stay on the safe side’ or ‘From father to son’ training – that are present in many places and do not always entail efficient operations.
The following exercises can be listed here:

  • Unit startup
  • Unit shutdown
  • Heater startup / shutdown
  • Compressor startup, etc.

Statistical data

Activities and evaluations that are summarised every year and constitute the basis of any assessment. Utilisation is one of the most important metrics for us, as well as for anyone interested. 

According to our assessment utilisation rate of the various OTS systems calculated as the ratio of used time to the available total accounted for about 75%. 

Besides these statistical data, different kinds of other information received about exercises, examination topics, trainers’ work and system reliability are likewise assessed. All of our data shows that although we have achieved significant improvement since the start, we still have a lot of potential not only in terms of training quality or quantity, but also in that of the level of our organisation. Shortcomings are corrected or eliminated continuously.

Development efforts

When we discuss maintenance or improvement of a company’s stability, efficiency or operability, components that are the key to higher performance – e.g. properly trained, highly qualified plant personnel at hand – must be treated as critical criteria. Every tool enabling the given employee to do – as it is expected – high standardized work as soon as possible must be treated as critical. 



Increasing the utilisation of training simulators used at Duna Refinery could be one of our priority goals. This could be achieved not only through even more training sessions for shift staff already subject to mandatory training, but also by engaging colleagues from other refineries within MOL Group. Additionally, ‘promoting’ training could also be a priority goal. This means that involving colleagues who would like to improve technological knowledge and experiences is also a possibility. In addition, engaging workers from plants that use similar technology could also be a goal for future training courses.


About the author

Tibor Szabó is a process automation expert for Production Excellence Department at MOL Duna Refinery. He is the OTS System Administrator in the Refinery, supervising and managing OTS operation, giving advices and supporting the instructors and liaising between the instructors and the supplier. Tibor has been working for MOL since 1994. He worked in FCC unit 13 years. Beside OTS system administration he has contributed to more projects. He has led the expert team in the preparation of the Electronic-logbook system and has been contributing to alarm management project in Duna Refinery. In addition, he is also a member of the project team to control energy efficiency and energy consumption all over the Downstream segment. Tibor received a bachelor’s degree from University of Gödöllő (Hungary). Connect with Tibor via LinkedIn.


This article was originally published in MOL Group scientific magazine 2013/1, original paper can be downloaded here.