Flow, level & control

Minimising costs through process optimisation

The control of industrial processes can be a complex operation involving multiple valves, sensors and controllers which means there are many considerations when looking for opportunities for process optimisation. Using best practice and ensuring control protocols are updated when process changes are implemented however, ensures the process remains efficient and effective. In this article, Greg Wainhouse, UK water segment manager at Bürkert, looks at some examples from different industries, where process optimisation can deliver significant improvements and reduce costs

way. From variable inputs to changing conditions and complex infrastructure, there is always another obstacle to overcome, but by taking advantage of expertise within the industry, it is possible to make significant practical improvements.


WasTe WaTer processInG One of the major challenges in the water treatment sector involves the sludge dewatering process, which in many cases involves high speed centrifuges that separate the solid and liquid fractions. To assist this process, a polymer is added to the sludge to help bind the solid particles together. The goal is to produce a final product that has the right consistency that makes transport efficient, without moving excess water to the fields, where it is spread as agricultural soil enhancer. The process has a number of variables,

including the percentage solids of the raw sludge, the flowrate of the sludge, the amount of polymer being added and the speed of the centrifuge. Of these, the solid content of the sludge is crucial to determine the settings for the rest of the process. There are several ways in which this can be

determined, including a process where a sludge sample is placed in a petri dish, and the water is evaporated off to obtain the mass of the solids. This is not a very efficient process and can take 45 minutes to complete. Once the results are available, the centrifuge and polymer settings can be adjusted and an improvement in the consistency of the dewatered sludge should be apparent. However, changes in the solids content can

occur frequently, which makes this process quite ineffective and labour intensive. In addition, it is a reactive process, more often


rocess control engineers are constantly aiming for perfection while all the time tackling the challenges that stand in their

Oxygen levels can be accurately controlled during fermentation to ensure optimum product quality

used when the consistency of the dried sludge does not meet expectations. During the time taken to observe the change, complete the test and alter the settings, the centrifuge has continued to discharge a sub- standard end product.

DealInG WITh solIDs In sUspensIon In the first instance, assessing the percentage of solids using a turbidity sensor located on the intake to the centrifuge will significantly increase the response time to any changes. These sensors look at refracted light to provide an approximation of the solids loading of the incoming sludge, but they can suffer from fouling problems, and the calibration process can be interpreted differently by various operators. By constantly monitoring the inlet of the

process, adjustments can be made quickly and the amount of processed sludge that falls below the required standard is minimised. Further improvements can be made by adding a flow meter, or better still a device that provides a mass flow measurement. By creating a pro-active system that makes

adjustments based on data from the inlet, as opposed to a reactive system that observes the results before implementing a change, process engineers will be following best practice. Furthermore, this setup reduces the amount of operator intervention and delivers a more stable output.

BreWInG perfecTIon An important part of the brewing process is adding oxygen to the wort to allow the yeast to thrive and create the alcohol and carbon dioxide. After the boiled wort has been chilled

April 2019 Instrumentation Monthly

Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80