Increased reliability of cruise ship’s LNG systems design with simulation-aided testing at Meyer Turku

Meyer Turku is one of the world’s largest and most advanced manufacturers of large cruise ships and passenger ferries. The highly modern luxury cruisers built at the Turku shipyard in Finland are known worldwide for their cutting-edge technology. A recent example of this is the Icon of the Seas, the world’s largest cruise ship built to date.

In the striving for more sustainable solutions, Meyer Turku has adopted LNG (Liquefied Natural Gas) as a marine fuel, a cleaner alternative to traditional marine fuel. Despite its environmental benefits, designing and commissioning of marine LNG systems for cruise ships presents unique challenges. These include higher procurement and installation costs, tighter safety requirements, and the need for rigorous operational testing and crew training.

To tackle some of these challenges, Meyer Turku partners with Semantum, a company expert in dynamic simulation solutions, to apply simulation-aided testing for the LNG fuel system of a state-of-the-art cruise ship. The project aims to ensure system reliability, reduce commissioning and FAT time, and enhance operational safety through simulation-aided tools.

  

A simulation-based solution based in Apros

At the core of the solution is Apros, a dynamic process simulation software developed for modeling and simulation of complex systems such as power plants and energy systems. Apros is instrumental in modeling the LNG fuel system in its entirety, including tanks, bunkering stations, vaporizers, boil-off gas compressors, auxiliary systems, and key control applications. This first-principles dynamic simulation enables a precise, high-fidelity representation of the system's behavior under various conditions.

The testing environment is built on an OPC UA-based architecture, ensuring seamless communication between the simulation environment and the actual control systems. OPC UA (Open Platform Communications Unified Architecture) is an industrial protocol for data exchange. This allows Apros to interface directly with Siemens SIMATIC PCS 7, the real Distributed Control System (DCS), and SIMIT, Siemens' simulation platform.

  

Simulation-aided testing of the cruise ship’s LNG fuel system

Simulation-aided testing refers to the use of simulation to test a system under study. In this project, the LNG fuel system is tested in two phases

1. Model-in-the-Loop (MIL) testing:

   In the MIL phase, the LNG system's simulation model is controlled by a control application model. This virtual setup allows the multi-disciplinary team to test different process designs, verify control logic, and identify potential issues. Apros' toolsets are used to systematically configure and execute the tests, ensuring precise synchronization and control over the process.

   Key outcomes of this first phase include verifying the behavior of control loops, analyzing transient impacts under operational changes, and identifying over 10 critical design issues. These refinements reduce the risk of malfunctions during commissioning.

2. Software-in-the-Loop (SIL) testing:

   In the SIL phase, the real control application in SIMATIC PCS 7 is connected to the LNG system simulation model via OPC UA. Over 1,200 tags are exchanged between the control system and the simulation environment, allowing realistic testing of sequences, interlocks, and safety protocols under simulated operational scenarios. This phase validated the real control application.

   A key strength of the setup is its flexibility. The test configurations from the MIL phase are easily adapted for SIL testing with minor adjustments. The SIL phase confirms the reliability of the control application, uncovers additional areas for optimization, and prepares the system for operational use and training applications. It also reduces time for FAT. Additionally, the same configuration is used for basic crew training.

 

  

  

Key role of Apros and OPC UA

Together, Apros and OPC UA are the foundations of the testing environment, creating a powerful synergy that streamlines the testing process and improves the overall reliability of the LNG system.

• Apros enables the development of a high-fidelity dynamic simulation of the LNG fuel system, capturing the behavior of complex processes such as boil-off gas management and operation transients and steady states. Its toolset and connectivity capabilities ensure the seamless execution of systematic testing, allowing stakeholders to verify the control application against a realistic process model. The simulation platform also facilitates iterative refinement to the system design and served as a foundation for future crew training systems and digital twins.
• OPC UA plays a key role in integrating simulation and control systems. Its data exchange capabilities ensure the continuous synchronization of process and automation variables between Apros and SIMATIC PCS 7. This allows comprehensive testing of control logic, operational sequences, and safety functions.

  

Key outcomes of simulation-aided testing for Meyer Turku

• Increased system reliability: Over 10 design and control issues were identified and addressed during MIL testing. Key safety-critical functions, such as emergency shutdown protocols, were rigorously tested and validated.
• Streamlined commissioning: By addressing potential failures early in the simulation phases, the team reduced commissioning time.
• Enhanced insights and training: The simulation environment provided a deep understanding of the LNG system’s behavior, offering valuable insights to both engineers and operators.
• Successful factory acceptance testing (FAT): FAT benefited from the refined simulation model, enabling realistic testing of the control application before the physical system is operational. This reduced FAT duration and increased confidence in system reliability. This is one of the main results from the SIL testing.

  

Future impact

The outcome of this work enables also adoption of other simulation-aided methods, such as crew training systems and operational digital twins. Furthermore, these results highlight the power of simulation-aided testing in design, commissioning and operation of modern cruise ships.