MODULE 8 Assessment of Existing Plants and Model Calibration

Once a simulator such as MODSIM has been mastered, the simulation of even complex plants becomes a straightforward task. It is a matter of specifying the flowsheet, choosing suitable models for the unit operations and characterising the feed material. The real difficulty with the method lies in the choice of parameters and settings for the unt models. In most cases these values do not have absolute values and they must be chosen to suit the characteristics of the particular material that is to be processed in a particular plant or installation . Usually the parameters have values that are strongly influenced by the material that is to be processed, so parameters parameter values must be obtained for every project. Parameters for the models can be obtained from data collected in the laboratory or from data that is collected on an operating plant. Clearly the second alternative is not available if the plant does not yet exist. A number of standard laboratory methods have been developed to measure the parameters for many of the models and one of these will be discussed later in the course. We will concentrate in this module on methods that can be used to obtain model parameter values from operating plant data and on the interpretation of these values in terms of plant performance.

OBJECTIVES OF THIS MODULE

1. Learn to use the features in MODSIM that can be used to compare simulation output with real data.

2. Learn to interpret parameter values in terms of the operating characteristics of the units and to diagnose operating problems.

3. Learn how to use simulation to achieve better plant operation.

Two examples are included in this module. The first examines an existing conventional grinding circuit and the second an existing milling circuit that has specific mineral liberation characteristics.

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