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Fault detection on pulp pressure screens

University of British Columbia

In this thesis the development of a strategy for the detection and isolation of faults particular to the pressure screens commonly used in mechanical pulp mills is presented. After exploring several non-model and model-based approaches for fault detection and isolation (FDI), a method is chosen. The method relies on the simultaneous identification of the states and process coefficients of a dynamic model for said screens. The criterion used in developing such a model is explained and the concept of "dynamical" friction coefficients as fault detection indicators is introduced. A technique called the Singular Pencil Matrix (SPM) for simultaneous identification of states and process coefficients is discussed and some simulation and industrial results using SPM are shown. As part of the validation of the dynamic model a reduced version of it is proposed and tested. The problem of modelling the process noise when applying SPM is discussed, some options are studied, and an alternative scheme based on cumulative functions for confirmation of screen faults is presented.

Thesis/Dissertation

application/pdf

2009-02-19

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http://hdl.handle.net/2429/4795

Electrical and Computer Engineering

University of British Columbia

UBCV

DSpace