Digital Twin of a Fertiliser Production Distributed Control System: Development, Use and Benefits

Keywords: Operator Training Simulator, training, ammonia, urea.

The Yara Babrala plant is a fully owned subsidiary of Yara ASA International and was commissioned in 1994. It has a single stream ammonia plant of 2,000 MTPD capacity and two streams of prilled urea plant of 1,750 MTPD each. The technology supplier of the ammonia plant is M/S HTAS (Haldor Topsoe) and that of urea is Snam Spa Italy. The site has been consistently recognised as one of the most energy and water efficient plants in the fertiliser sector, among similarly aged plants.

Yara Babrala was experiencing a high turnover of control room operators during 2007-08, which increased the need for faster training programs. At the same time the implementation of Advanced Process Control (APC) in the ammonia and urea plants meant that control room operators were not exposed as much as previously to startup, shut down and troubleshooting experiences. Many industrial accidents occur because of the gap in required competencies for plant operations, and a lack of practical exposure in handling process upsets and malfunctions. A high-fidelity Operator Training Simulator (OTS) can bridge this gap by combining both theoretical knowledge and practical experience by leveraging the technology modelling software through a customised OTS.

To address all these challenges Yara Babrala decided to implement a direct connect OTS for the ammonia and urea processes. The direct connect OTS deployed supports field and console stations functionality, and the models are scalable along with comprehensive training features. The console stations are exact replicas in terms of hardware and functionality of the real Distributed Control System (DCS), so that operators can practice in a simulated environment rather than on a real DCS. It enables operators to develop competencies in a safe, standardised, and repeatable manner. The evaluation features provide timely feedback to trainees. The built-in features help instructors to identify areas for improvement during training.

These OTS training modules enabled Yara Babrala to reduce the learning curve of new control room operators from around nine months to three months. In addition, the competency of experienced operators was enhanced by practicing unforeseen scenarios, plant upsets and learning from other plant’s incidents. Yara Babrala also used the OTS to test any proposed operating procedures (SOP), what if analysis, and HAZOP recommendations. The OTS has now become one of the main and effective training tools at the site and Yara Babrala has achieved all the envisaged benefits of the OTS project.