Category: Plastics & Chemicals

Plastics & Chemicals

Rules of Thumb: Flow Parameters

Stephen Hall discusses the golden rules for design RULES of thumb are sometimes misleading. Engineers often discuss rules of thumb for pipe sizing. Velocity (1–4 m/s) and Reynolds number (>10,000) are cited, as are pressure drop (20-80 kPa/100 m) and shear stress (>5 Pa). Given a flow rate and pipe size, these charts give a…

Plastics & Chemicals

Rules of Thumb: Chromatography Systems

Stephen Hall provides practical insights into on-the-job problems CHROMATOGRAPHY forms the heart of the purification train for many bioprocess facilities. In a typical train, three or four chromatography steps are used to remove impurities and side products from the bulk product that is harvested from bioreactors. Each step employs a specific resin that preferentially bonds…

Plastics & Chemicals

Handle with Care

Nikodem Siwek explains how to get the most from your pH measurement devices THE arduous nature of chemicals processing applications can be especially tough on pH sensors, making correct selection and maintenance especially important. This article looks at how to get the best performance out of pH measurement equipment and how developments in digital sensing…

Plastics & Chemicals

Rules of Thumb: Control Valve Lift

Stephen Hall discusses the golden rules for design CONTROL valves provide a way to modulate the flow rate through a line, maintain the level in a tank, or adjust the pressure in a pipe. A sensor measures the desired value and a controller slightly opens or closes a valve if the measured value differs from…

Plastics & Chemicals

Carbon Capture: But Not as We Know It

Rotating packed beds can play a part in making carbon capture smaller and cheaper CLIMATE change is the most important long-term issue facing humanity. It is now clear that the sum consequences of business-as-usual CO2 emission would place severe strains on global food security and water supply, causing substantial damage to social, economic, and political…

Plastics & Chemicals

Opening Up Instrumentation

John de Mello explains how scientific instrumentation is becoming more open, more affordable and easier to make UNTIL recently, if you needed a scientific instrument, you had two options: you could buy a ready-made system or you could design and build one yourself. The first option was expensive, but the second was tricky and time-consuming.…

Plastics & Chemicals

Rules of Thumb: Tanks and Vessels

VESSELS provide many functions in a chemical plant. They have many forms and sizes, and are fabricated from nearly any structural material. Vessels contain valuable inventory that can be hazardous to life and property if released, so it’s important for process engineers to pay close attention to the use, sizing, and design of all of…

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