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How long does it take to reach steady state?

How long does it take a six-tray, 4-ft dia. deisobutanizer to achieve steady state? That depends on your definition of “steady state”. Some control experts regard 95% of “ultimate value” as a good definition, but how useful is that definition?…

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Preventing Self-Heating and Ignition in Drying Operations

Many solid materials can exhibit self-heating, which — if unchecked — can progress to a fire or even explosion. And even if the situation does not get that far, it is likely to affect the output of the process, in…

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When troubleshooting the extractor

I have an ongoing dispute with a longtime colleague, Bob Miller. I said he ruined my new safety boots. He said he didn’t. Bob was a young, fearless distillation engineer at a time when our extraction engineer refused to take…

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Gas-Liquid Mixing: Physical Considerations

Gas-liquid reactors in the chemical process industries (CPI) have increasingly been designed to handle larger manufacturing scales. Since gas-liquid reactors can represent substantial capital and operating costs for the user, optimizing mixing and maximizing productivity are critical. The need for…

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Heat Exchangers for Hot Acids: Material Selection

To make the modern materials we use every day, such as plastics, metals, electronics, pharmaceuticals, fuels and so on, strong acids are used to convert the earth’s raw materials into modern materials. In fact, so many tons of acid are…

A Clearer View Of Crystallizers

Improved understanding of crystallizer equipment and operation can aid purification efforts in the CPI Crystallization is a key purification technique for various sectors of the chemical process industries (CPI). Several approaches for industrial crystallization have evolved over time, and highly…

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Liquid-Gas Coalescers: Demystifying Performance Ratings

Engineers working in the chemical process industries (CPI) sometimes have to deal with aerosol contamination issues in which liquid-gas coalescers are routinely employed. For example, liquid-gas coalescers are used to protect compressors, liquid-gas contactors, turbines, low-NOx burners, metering and instrumentation…

New Piping Code for High-Purity Processes

In the emerging and ever-expanding areas of bioprocessing, where maintaining hygienic designs and practices is of paramount importance, and semiconductor manufacturing, which has its own stringent purity requirements, there is a need to standardize the essential codes and standards that…

Inspecting Fractionation Towers

Distillation columns are often workhorses in the chemical process industries (CPI), and at times, it is necessary to physically inspect the interior of a column. This article demonstrates what an inspection can reveal, by sharing the experience of actual fractionation-tower…

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Compact, High-efficiency Heat Exchangers: Understanding Fouling

The topic of fouling in heat exchangers has been of increasing interest in recent years, since it is so closely linked to the cost of building and running a chemical plant. It has been reported that fouling costs are about…