People often battle for long periods trying to tune a controller to eliminate problems. As I have often said, one of the biggest fallacies found in plants when it comes to control is that “all problems ...
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I have come across quite a few control loops that were doing a reasonable job of control and which were in fact completely unstable, and in some cases were working much better than if the loop had been ...
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I recently wrote a Case History about control problems in a minerals extraction plant in Portugal, which was experiencing great difficulty with the control on their flotation banks. I have also written ...
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I was recently asked to advise on a bad pH control problem in a water treatment plant. A new carbonisation bay had been installed at the plant: Figure 1 shows the layout of the bay and controls. Raw water ...
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I have written quite a few articles specifically dealing with control problems in mineral processing plants that are largely due to poor understanding, and apparently complete lack of concern of control ...
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The practice of industrial feedback control is one of the most misunderstood engineering disciplines in the world. The theory was developed by eminent mathematicians in the early 1900s and was based on ...
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The longer I work in the field of control loop optimisation, the more I learn that things often do not work the way one expects. I have spent over 30 years optimising literally thousands of feedback control ...
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Problems on a flow control loop    The first example is that of a flow control loop on a liquid flow. Figure 1 shows a closed loop test with a step change of setpoint.    Three problems immediately stand ...
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I have received some comments from Saul Mtakula, a control engineer originally from Zimbabwe but now residing in Canada, about one of my Case History articles, No. 126, published in 2012 under the heading ...
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A friend of mine was appointed to start an advanced control and optimisation group in a very large chemical plant and he hired a group of academically highly qualified young APC (advanced process control) ...
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In this article we look at three cases where great success was achieved through optimisation. The work was all done in a petro-chemical refinery.       Case study 1 The first example is of a reactor feed ...
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As a break from the problem reports presented in the last few Case Histories, this article will discuss some problems I encountered recently at a zinc mining plant in Europe where I carried out a base ...
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