Cement, Energy and Environment

I I I QCX/BiendExpert Raw mix control 1 at- line X RF Feeder set points ~ Software module .... Process Row - Sample flow Raw material feed • • • . ' , . • • • . . . ' . I - I ftl-' -:l:: ' • . III! J -- •-aama ' v- , ·u :-Rf.-tnl . - ;...... ' I \ 0 - Control loop .. -~ - -·- '--r~-,4--• QCX Core - Analysis data flow @At-Une XRF @t...bXRF Applying best practice sample preparation, the control loop is self contained, e.g. compared to earlier at-line x-ray solutions from FLSmidth a dual "inner & outer" loop control structure is no longer necessary. The at-line XRF application is based on a series of spot samples (optionally few minutes composite samples) taken with some minutes interval. If the central laboratory XRF analyzer is also part of the installed QCX system structure, a simple switching can activate the laboratory XRF based control loop to take over responsibility for the mix control , now based on conventional samp ling. This provides a robust structure which is tolerant to errors in any of the two analysis instruments. Operationa l benefits At-line XRF analysis is one of more possible technologies delivering tight raw meal quality control. On-line PGNAA (Prompt Gamma Neutron Activation Analysis) installed on the feed stream to a raw mill is another widely applied technology. Both technologies can be regarded as mature with +20 years of application history and several successful installations behind them. One major advantage with the X- ray based at-line technology is that it does not employ any radioactive components. !hus, n~ time consuming paper work is Involved 1n obtaining shipp ing of radioactive sourc~s/neu tron tubes, as well as obtaining operational permits for same, which is one of the burdens coming with PGNAAs. While an at- line XRF installation will demand more maintenance work than what's associated with PGNAAs, an at-line XRF solution employing a cost effective XRF analyzer is available at a lower installed price than a PGNAA solution for the same on-line raw mix quality control objectives. In fact, when compared to the PGNAA concept, FLSmidth's new at-line XRF solution for raw mill quality control offers many advantages. Foremost, best practice sample preparation eliminates the need for frequent 'check' samples (outer loop samples/bias compensation samples) employed by most other on-line/at-line analysis applications around the raw mill. In summary, in a comparison with a PGNAA based QC concept , the at-line XRF solution offers: • • • • • • • Lower initial capital investment Lower operating costs No safety issues with neutron radiation No red tape associated with neutron source delivery Best practice analytical performance Ability to analyze ad-hoc manually- introduced samples Ability to support two nearby sampling points with one unit • Even better control performance. Courtesy: Industrial Angles, May 2014, Vol.3, Issue II, pp 59-62 II