In this issue of Process Heating, we take a look at water treatment and corrosion control, heat transfer fluids and drying technology. Whether you need to make something hot or cool, wet or dry, you’ll find information to benefit your process.

In “Drying-Process Effects on Rayon Fibers,” Shannon Stanforth of Buhler Aeroglide reports on testing the company performed to determine how drying time and temperature affect key characteristics of rayon fibers. A versatile fiber, rayon is valued by consumers for its comfort, softness and breathability. Rayon producers seeking to increase production speed by increasing process air temperature and reducing product retention time within the oven must balance speed with the finished rayon characteristics. Drying at too high a temperature can cause yellowing of the rayon fibers, reducing their value. Stanforth details a study undertaken to measure how fiber whiteness and yellowness, strength and oil pickup are affected when the drying process parameters are adjusted.

Just how the sand used in hydraulic fracturing is produced is the focus of “Using Rotary and Fluid Bed Dryers for Drying Frac Sand” by David Phillips Heyl & Patterson Inc. The sand, which is mined in the Midwest and other areas from glacial deposits, must be washed, dried and refined by sorting before it can perform its essential role in oil- and gas-well production. Rotary or fluid-bed dryers can be used to perform the thermal processing.

Also in this issue, our Equipment Overview on Dryers provides you with a shortcut to prospective suppliers. In print and online, you can find companies that manufacture equipment with the capabilities and features you need for your process.

Aside from drying technologies, this issue also includes information on heat transfer fluids and water treatment. In “6 Takeaways for Heat Transfer Fluids,” Conrad Gamble, P.E., of Eastman Chemical Co. describes six common process challenges — situations you may have found yourself in — and explains what you should (and should not) do in those circumstances. To err may be human, but human error can certainly create problems. His advice may help your plant avoid pitfalls that have tripped others up.

In “Testing PG- and PDO-Based Heat Transfer Fluids,” Lirys Crawford of DuPont Tate & Lyle reports on testing performed on two types of glycols used as heat transfer fluids. As he notes, though the type of glycol used in the fluid formulation may not always be the primary consideration when choosing a product, PDO-based fluids can provide benefits for some applications.

 Finally, in “Taking Control of Corrosion,” the engineering staff at U.S. Water offers an overview of the 10 common types of corrosion as well as ways to avoid having it sideline your process equipment. Depending on the types of corrosive attack on your system, even small changes can weaken the equipment to the point of failure. Being aware of the mechanisms that contribute to corrosion can help when planning preventive maintenance and repairs.