In my cub reporter days, I worked part-time at a service station and auto parts store. My job primarily consisted of accepting payment from those purchasing gas and selling the sundries one might pick up at a neighborhood quick-stop shop. My area occupied a small nook near the entrance, while the rest of the building was given over to a complete automotive parts store along with two repair bays where mechanics worked during the day. The pay was great for a part-time job, the job wasn’t taxing, and I met a lot of interesting people. In all, it was ideal side-gig until the night it burned to the ground.
As luck would have it, I was one of two who closed up shop on the last night. A few hours later, a family member of mine was driving by and noticed the smoke and flames. The fire department was quickly called, followed by a call to me. Strangely (or perhaps not so strangely, in hindsight), the fire inspector found all of these facts rather … convenient. Though I hadn’t done anything wrong or out of the ordinary, both my colleague and I faced some tough questions about what had happened while we were closing shop. We were both cleared when the cause was identified as spontaneous combustion of some rags the mechanics had left piled in a cardboard box.
Though decades have passed, I still remember my surprise at the source. (This was before my Process Heating days, and I didn’t understand yet how many ways things can ignite if the three legs of the fire triangle are satisfied.) I see echoes of that surprise when I speak about the dangers of combustible dust. Just as the mechanics grew lax with their oil- and grease-filled rags, overlooking their hazard potential, some of those in plants with chronic powder and dust buildup throughout the plant may overlook the hazards. Familiarity breeds complacency.
In his article, “Understanding Your Powder’s Self-Heating Hazards,” Dr. Vahid Ebadat, the CEO of Stonehouse Process Safety Inc., Princeton, N.J., focuses on methods to test dry bulk powders in your facility to determine if, and at what quantity, the material will self-heat, smolder and combust. As Dr. Ebadat says, “Knowing your powder’s potential for self-heating will allow you to specify operating, storage, packaging and transportation conditions that will reduce the risk of self-heating.” The article describes four tests used to simulate the conditions that the powder experiences during drying and downstream processes to quantify the powder’s potential for self-heating.
Also in this issue, Steven Onsager and John Hober of Precision Quincy, South Beloit, Ill., look at the reasons that ovens may require repair, retrofits or even replacement. Industrial ovens are incredibly long-lived process equipment — 20 and 30 years is common for process ovens, and even 50 years is not unheard of. At the same time, the products for which the ovens are used for thermal processing evolve with changes in customer demand, manufacturing materials used, and markets served. Though the oven’s most basic function — to thermally process product — remains, such changes may lead to a day when the processor realizes the oven is not meeting the company’s needs. In those moments, a new system may be the best option, it pays to weigh whether repairs or retrofits can reestablish efficient processing.
In “Drying with IIoT and Cloud-Based Data Management,” Paul McKeithan of Bühler Aeroglide, Cary, N.C., explains how process automation and controls allow you to monitor drying operations and manage the process based on key performance indicators. Smart sensors and integrated controls allow drying product to precise moisture levels without overdrying, helping processors to better control operating costs.
Finally, in “Heat-Exchange Technologies for Effective Food Pasteurization.” Matt Hale of Atlanta-based HRS Heat Exchangers describes how pasteurization technology may be able to help some food processors improve or upgrade current processing capabilities.