Digital twin technology is becoming increasingly widely acknowledged as a more effective and risk-free way to test and achieve operational advances.
In the mining industry, while the process of comminution plays a vital role in liberating valuable minerals from ore, achieving optimal control of comminution circuits is an ongoing challenge, with large variations in feed and operating conditions affecting efficiency. In a recent project, technology pioneer ABB, and Swedish multinational metals, mining, and smelting company Boliden discovered new ways to address this issue — through the use of a digital twin.
The evaluation was conducted at Boliden’s Aitik site, where a digital twin representing the comminution process was used to evaluate different control strategies for addressing a range of processing scenarios.
“The virtual environment of the digital twin enables experiments that are unobtrusive to everyday plant operations,” shares Ryan Koorts, Global Product Marketing Manager – Process Performance, Digital business, Process Industries at ABB.
“As well as removing the risks of business disruption, these exercises can be performed in a relatively short time, with the possibility of testing extreme operational conditions as well as different circuit configurations. The result, as shown by the ABB and Boliden project, is the development of multiple robust control strategies capable of dealing with the vast array of possible scenarios that can occur on-site in the mining industry.”
Ryan Koorts has been at ABB since 2017, having worked at companies including Vector, SGS and 4Sight (formally BlueESP) focusing on process plant optimisation utilising advanced process control in mining, oil and gas refining and cement industries. Based in Switzerland, he is currently ABB’s Global Product Marketing Manager – Process Performance, Digital business, Process Industries.
Significant operational improvements using a digital twin
In the project, three main components were used to create a virtual environment.
“An OPC connection interacted with the digital twin plant simulator in real-time, enabling the tracking of data of the simulated plant as well as the implementation of changes from external sources to control the process,” Koorts says.
“A direct copy of the ABB 800xA plant control system, including customised logic and interlocks, was used for the base layer control. This approach was followed to maintain, as far as possible, a realistic replication or virtual version of the actual plant setup and configuration. ABB Ability™ Expert Optimizer forms part of the ABB Industrial Software suite and hosts the advanced process control (APC) strategy.
“For a primary grinding circuit, the key optimisation objectives are to improve the mineral liberation, maximise production, decrease energy consumption, reduce the usage of grinding media, and improve process stability. APC is a useful tool for balancing these objectives in real-time and optimising the economic model of the plant. Controlling a grinding process presents several key challenges, including large time delays, uncontrollable disturbances, nonlinear process behaviour and a lack of instrumentation, and most importantly, varying operator expertise levels and attention – highlighting the need for an autonomous standardised APC solution
“APC is a technology that is geared to tackle multivariable type problems, typically experienced in complex process plants. APC constantly looks to minimise process variability and drive the process to an optimum, as defined by the user. Leveraging the digital twin platform, the APC tool could be rigorously tested, adapted and tuned before undergoing a benchmarking exercise. A comprehensive number of simulations were run in the digital twin environment to test the performance of the control strategy. The APC solution in ABB Ability™ Expert Optimizer was then compared to the current on-site PID-based control strategy. The key results achieved through digital twin technology were:
- Throughput increased from 1% to 3%
- Maximisation of torque increased from 1% to 7%
- Disturbance rejection increased from 0.5% to 3.5%
- Response time and circuit stability with STD reduced by > 5%
How can digital twins positively affect the mining industry?
The project results highlight the extensive value of digital twin technology for the mining and minerals industry, successfully using the comminution digital twin to evaluate multiple operating scenarios under different control strategies — without disrupting plant operations.
“The simulations show that the APC controller improved process performance in relation to the four main KPIs: throughput, utilised energy, grinding energy and sieve size,” confirms Koorts.
“This success was directly related to the fidelity and accuracy of the digital twin simulation. The impact of the project demonstrates that, with the right approach, pairing up industry with digital innovation can drive significant operational improvements, while supporting business-as-usual.”
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