Aggregate plant flow modeling in North America relies
heavily on the use of crusher manufacturer provided gradations.These gradation estimates may provide a
useful starting point when no other data are available.At existing plants, sporadic measurements of
crusher feed and discharge gradations may be available.These gradations may represent different
plant processes or modes and therefore must be managed separately in the plant
flow simulator.Furthermore, what
happens when you change a screen upstream of the crusher during “WhatIf” scenarios.Did your plant flow modeling program
dynamically change the crusher discharge based on the resulting change to the
crusher feed using “real-world” measured data?
Stonemont works with over 2000 plants in North America and
has noticed that there is a growing trend to implement more regular sampling in
aggregate plants beyond the finished products, especially at crushers.Certainly our crusherQC product facilitates
the entry, analysis, and reporting of this data.However, there has to be a better way to
utilize this data in plant flow modeling than static discharge gradations that
are no longer useful in “What If” scenarios.One answer is to create a dynamic model of the crusher using crusher
tests analyzed by crusherQC and implement the model in plantFlow.
Example of Crusher Modeling in crusherQC and plantFlow.
Crusher modeling in crusherQC and plantFlow uses the Whiten
(1972) crusher model to simulate the classification and breakage functions of
the crushing process.The Whiten model
requires that classification parameters (K1,K2,K3) and a breakage parameter
(T10) be defined.These parameters
relate back to the crushing process; K1 is the size below which all particles
escape breakage; K2 is the size above which all particles are crushed; K3
describes the shape of the classification function; T10 is the percent of
product passing 1/10th of the original particle size, after
breakage.These parameters can be
readily determined by fitting the appropriate equations to crusher feed and discharge
gradations.However, what makes the
model useful is that the parameters are largely functions of flow rate, feed
size and liner characteristics.For
example, the cone crushing process at a particular operation can be effectively
modeled using “real-world” measured values such as closed-side setting (css),
flow rate (tph), 80% passing feed (f80), liner age (lhr), and a few other
optional parameters.Crusher modeling in
crusherQC and plantFlow has been optimized by allowing the user to quickly evaluate
which parameters (CSS, TPH, etc.) best-fit the crusher model.
The end result is an aggregate plant flow simulation model
that dynamically simulates changes to the crusher discharge gradation resulting
from a changing feed distribution caused from crusher, screen, or other plant
configuration changes upstream. For more information contact Stonemont Solutions, Inc.
