Met Dynamics, in association with Bear Rock Solutions, has developed a sophisticated model of gyratory and cone crushers that can greatly aid the optimisation of process performance through the mechanical design of the crushers and liners.
The Kinematic Crusher Model (KCM) meshes a mechanical description of the crushing machine with the breakage characteristics of the feed material.
The KCM therefore allows the examination of not only process performance, but also the mechanical response of the crusher.
Based on the work of Bearman, Briggs and Evertsson, the model couples a geometric description of the crusher chamber with equations of particle motion and a population balance breakage model.
The model is then able to predict:
- product size distribution;
- power consumption;
- internal chamber conditions; and
- on-set of packing and power overload
for any given combination of:
- mantle and concave liner geometry;
- Closed Side Setting;
- eccentric throw and speed; and
- feed rate, size distribution and material hardness.
Some of the key model diagnostics include:
- Definition of the chamber choke point;
- Changes in bulk density due to size reduction and progression through the chamber;
- Distribution of crushing power and mantle pressure in the chamber;
- Ability of the liners to accept, nip and break materials at points through the chamber; and
- Crushing force or piston pressure developed during a cycle.
Crusher liner wear
The Kinematic Crusher Model also incorporates a simulation module that predicts liner wear over time.
Worn liners change the geometry of the crushing chamber and can result in drifting closed side settings, poor throughput, power consumption and product quality.
Automatic setting regulation is often used to compensate for liner wear. The KCM can simulate wear in both gyratory and cone crushers, with or without regulated setting controls.
The wear simulation allows a user to predict the economically optimal time to replace liners, given any set of material type, duty, throughput and product quality requirements.
The KCM has been integrated with the SysCAD flow sheet simulation platform, allowing both the steady-state and dynamic process analysis of circuits.
When coupled with Met Dynamics existing suite of customised crushing, grinding and classification models, highly complex flowsheet behaviour can be visualised, understood and optimised.
Flowsheet simulation is a powerful tool when applied to enterprise energy minimisation or plant product quality improvement activities.
Example flowsheet applications include:
- Selection and sizing of equipment for tightly coupled primary-secondary crushing systems;
- Plant-wide asset utilisation, including liner wear and replacement, optimised setting regulation;
- Improved feed preparation for downstream operations, e.g. SAG mill pebble crushing, HPGR presentation;
- Balanced multi-stage crushing, primary to quaternary, e.g. iron ore, aggregates production; or
- Energy-efficient comminution in a plant-wide context.