| Abstract |
The Department of Energy (DOE) Industries of the Future (IOF) program seeks development and implementation of technologies that make industry more efficient - in particular, more energy-efficient. Quantum Magnetics, Inc. (QM), a wholly-owned subsidiary of GE Security, received an award under the program to investigate roles for low-cost Nuclear Magnetic Resonance (NMR) technology in furtherance of these goals. Most NMR systems are designed for high-resolution spectroscopy applications. These systems use intense magnetic fields produced by superconducting magnets that drive price and operating cost to levels beyond industry tolerance. At low magnetic fields, achievable at low cost, one loses the ability to obtain spectroscopic information. However, measuring the time constants associated with the NMR signal, called NMR relaxometry, gives indications of chemical and physical states of interest to process control and optimization. It was the purpose of this effort to investigate the technical and economic feasibility of using such low-field, low-cost NMR to monitor parameters enabling greater process efficiencies. The primary target industry identified in the Cooperative Development Agreement was the wood industry, where the moisture content of wood is a key process parameter from the time the cut tree enters a mill until the time it is delivered as pieces of lumber. Extracting the moisture is energy consuming, and improvements in drying efficiency stand to reduce costs and emissions substantially. QM designed and developed a new, low-cost NMR instrument suitable for inspecting lumber up to 3 inches by 12 inches in cross section, and other materials of similar size. Low cost is achieved via an inexpensive, permanent magnet and low-cost NMR spectrometer electronics. Laboratory testing demonstrated that the NMR system is capable of accurate (plus or minus 0.5%) measurements of the moisture content of wood for moisture ranging from 2% to over 140% (referenced to the wood's dry weight). Accuracy exceeded that offered by existing instrumentation when the moisture content was in excess of the fiber saturation point (approximately 20%). Accuracy was independent of the wood form: solid wood, wood chips or sawdust. The prototype NMR system was designed and built for incorporation and use in a beta test site. Beta testing is under way at the pilot plant operated by the Pulp and Paper Research Institute of Canada (PAPRICAN) in Vancouver, B.C. |
