PART 1: Dynamic process simulators can take the safety onus off mining plant operators, writes Neil Freeman.
The traditional view that minerals processing operations are all about shovels and conveyors is changing. There is an increasing awareness of the complexity and demanding requirements for the efficient operation and maintenance of mineral processing plants. Coupling this with occupational health and safety places a heavy onus of training on owners. This two-part serries attempts to take the onus off mining plant operators.
Extensive use of dynamic process simulators is becoming the norm for greenfield facilities in metals and mining, including alumina refineries. Many leading companies (including Rio Tinto Alcan) are benefiting from the use of dynamic simulation for greenfield projects and control upgrades because of the inherent risk in new process plant design and the complexity of controls. Interactive simulation provides enhanced operator training.
Simulator benefits
One of the major benefits of using simulation technology is for improving operator effectiveness. In many operations the equipment is used continuously and many operators are not well practiced in running under start up, shut down, or emergency conditions. Similarly, in new installations, operators may have even less skills in managing the process and the knowledge of the equipment limits, even under normal operating conditions. The essential mechanisms in learning are comprehension and repetition.
BYL
Building a simulator
A correctly-built dynamic simulation is a tool that can be used throughout an operations lifecycle. In order to fully realise the benefits it is necessary that a full high fidelity model of the process is built.
A high fidelity process simulation model will provide realistic hands-on experience without risk of damaging the plant. The simulator must have the same look and feel as the real plant.
For a project, the major uses of dynamic simulation are for process engineering, control engineering and operations training. Each of these areas will provide significant benefits, and the simulator should provide for all these functions.
Simulator applications
A custom simulation model of the process, control and logic systems can be delivered which would include malfunctions, process disturbances, training performance assessment, event recording, third party applications and training exercises. This simulation model can then be used during start-up and shut down, during normal operations and when new technologies – either control or process – are trialled. It can be specifically used to train operators, maintenance and engineering personnel how to run the plant.
Some vendors offer standard models which are ‘off-the-shelf’ examples of typical processes which meet industry standards and specifications. Although generic in nature, standard models are realistic in how they operate and respond to changes. They include process-specific malfunctions and disturbances, selected user functions, and training exercises. They may utilise a distributed control system (DCS) operator console or the colour monitor of the simulation computer.
The standard models are a useful alternative when only general process knowledge is required, or when the simulation budget is limited.
A custom dynamic simulation model can be used during the engineering design phase of the process and control systems to vet designs and uncover potential start-up problems. It can also be used to assist in evaluating modifications to existing plants. It can be specifically used to: test design philosophy; locate design flaws; identify constraints in existing or proposed equipment; test alternate designs; develop start up and operations plans and procedures; and conduct HAZOP studies.
Some dynamic simulators offer full emulation of control algorithms for DCS or PLC systems. This allows for the validation of control strategies off-line. As well, the simulation model can be connected to the operator console and the control devices to completely check out the implementation of the DCS control database, safety systems, graphics and alarming systems.
[Part 2 of ‘Training with dynamic simulation’ will be published in the July issue of PACE magazine.]
Honeywell Process Solutions