Perfectly blending powders and granules can be a significant process engineering challenge. Achieving a uniform blend depends on many variables: the right amounts of the right ingredients; the right particle sizes, moisture content, and temperature; the right process parameters like blender fill fraction, rotation rate, and blend time; and many other product-specific variables. Blending processes are typically qualified through careful experiment by blending batch after batch, varying parameters, taking the resulting blends to the lab for analysis, and then locking down on the single approach that works best. But what happens when one component arrives with a different particle size, or the factory is especially humid that day? There is still a path to a perfect blend, but it might not be the one qualified by process engineering. A bad blend can create any number of problems, from poor tableting to out-of-spec, waste product to, in the worst case, product recalls. One needs a process that can adapt to changing conditions and deliver the perfect blend every time.
One powerful way to build adaptability into a process is real-time process monitoring. Real-time monitoring can flag a process that is off course and, in many cases, even provide insight on what course corrections are needed. Near-infrared spectroscopy (NIRS) is a non-invasive, non-destructive method of chemical analysis ideally suited to real-time blend monitoring. Most NIRS instruments are benchtop, though, so how does one connect a bulky, wired instrument to a 1000 liter tumble blender rotating at 12 RPM? Of course, one can’t. But thanks to technological innovations in miniaturization and photonics, all of the essential functions of a benchtop NIRS are now embodied in a lightweight, battery-powered, wireless instrument—the VIAVI MicroNIR™ PAT-Wx—that can be readily mounted onto a tumble blender. Real-time blend monitoring has arrived.
The MicroNIR PAT-Wx is a full-function, built-to-purpose spectrometer specifically designed for real-time, non-contact monitoring of processes on dynamic or moving equipment like tumble blenders. It is fitted with an internal nine-axis inertial measurement unit (IMU) that enables highly accurate and repeatable triggering of the spectral acquisition at ideal, predetermined points in the blender rotation. The PAT-Wx is supported by MicroNIR Pro software, a complete, easy-to-use, GMP-compliant chemometric modeling suite with tools specifically designed to monitor blending processes. Chemometric modeling is typically a time-consuming process, but MicroNIR Pro software includes “unsupervised” blend-monitoring algorithms that require no prior training or model-building, making adoption a simple matter. The algorithms can provide process insight and determine the perfect end point, avoiding over- and under-blending. The PAT-Wx is rated for use in hazardous locations and is safe in the presence of flammable gases, vapors, dust, and fibers, certified worldwide by ATEX, NEC, and IECEx. A model for ordinary, non-hazardous locations is also available.
Real-time NIR blend monitoring yields tremendous benefits to pharmaceutical, nutraceutical, food, and feed manufacturers. NIRS provides insight on process dynamics to accelerate process development, minimize production cycle time, and reduce the cost of producing high-quality products.