Dryer Effluent Monitoring in a Chemical Pilot Plant via Fiber-Optic Near-Infrared Spectroscopy

1998 ◽  
Vol 52 (5) ◽  
pp. 717-724 ◽  
Author(s):  
Charity Coffey ◽  
Alex Predoehl ◽  
Dwight S. Walker
Keyword(s):  
Real Time ◽  
Pilot Plant ◽  
Near Infrared ◽  
Fiber Optic ◽  
Tunable Filter ◽  
Calibration Model ◽  
Gas Cell ◽  
Rotary Dryer ◽  
Vapor Stream ◽  
Effluent Stream

The monitoring of the effluent of a rotary dryer has been developed and implemented. The vapor stream between the dryer and the vacuum is monitored in real time by a process fiber-optic coupled near-infrared (NIR) spectrometer. A partial least-squares (PLS) calibration model was developed on the basis of solvents typically used in a chemical pilot plant and uploaded to an acousto-optic tunable filter NIR (AOTF-NIR). The AOTF-NIR is well suited to process monitoring as it electrically scans a crystal and hence has no moving parts. The AOTF-NIR continuously fits the PLS model to the currently collected spectrum. The returned values can be used to follow the drying process and determine when the material can be unloaded from the dryer. The effluent stream was monitored by placing a gas cell in-line with the vapor stream. The gas cell is fiber-optic coupled to a NIR instrument located 20 m away. The results indicate that the percent vapor in the effluent stream can be monitored in real time and thus be used to determine when the product is free of solvent.

scholarly journals Real-Time Release Testing of Herbal Extract Powder by Near-Infrared Spectroscopy considering the Uncertainty around Specification Limits

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Guolin Shi ◽  
Bing Xu ◽  
Xin Wang ◽  
Zhong Xue ◽  
Xinyuan Shi ◽  
...  
Keyword(s):  
Product Quality ◽  
Real Time ◽  
Near Infrared ◽  
Multivariate Calibration ◽  
Process Analytical Technology ◽  
Herbal Extract ◽  
Calibration Model ◽  
Validation Data ◽  
Specification Limits ◽  
Release Testing

The concept of real-time release testing (RTRT) has recently been adopted by the production of pharmaceuticals in order to provide high-level guarantee of product quality. Process analytical technology (PAT) is an attractive and efficient way for realizing RTRT. In this paper, near-infrared (NIR) determination of cryptotanshinone and tanshinoneIIA content in tanshinone extract powders was taken as the research object. The aim of NIR analysis is to reliably declare the extract product as compliant with its specification limits or not. First, the NIR quantification method was developed and the parameters of the multivariate calibration model were optimized. The reliable concentration ranges covering the specification limits of two APIs were successfully verified by the accuracy profile (AP) methodology. Then, with the designed validation data from AP, the unreliability graph as the decision tool was built. Innovatively, the β-content, γ-confidence tolerance intervals (β-CTIs) around the specification limits were estimated. During routine use, the boundary of β-CTIs could help decide whether the NIR prediction results are acceptable. The proposed method quantified the analysis risk near the specification limits and confirmed that the unreliable region was useful to release the product quality in a real-time way. Such release strategy could be extended for other PAT applications to improve the reliability of results.

The Detection of Soil Parameters by Portable near Infrared Spectrometer

2011 ◽  
Vol 128-129 ◽  
pp. 718-726 ◽  
Author(s):  
Yu Fei Li ◽  
Da Cheng Wang ◽  
Dong Yan Zhang ◽  
Da Zhou Zhu
Keyword(s):  
Organic Matter ◽  
Near Infrared ◽  
Ammonium Nitrogen ◽  
Tunable Filter ◽  
Field Analysis ◽  
Soil Parameters ◽  
Calibration Model ◽  
Infrared Spectrometer ◽  
Near Infrared Spectrometer ◽  
Nitric Nitrogen

Soil test is the key-point for formulated fertilization. The traditional chemical analysis methods for estimating soil nutritional parameters were time-consuming. The present aims to use portable acousto-optic tunable filter (AOTF) near-infrared (NIR) spectrometer to measure soil parameters, thus provide basis for field analysis of soil quality. A total of 231 soil samples were collected, Partial least squares (PLS) was used to construct the calibration model between the NIR spectra and the reference values measure by standard chemical methods, including organic matter, pH, ammonium nitrogen, nitric nitrogen, and total kalium content. Results showed that the prediction of organic matter and pH had high correlation (R=0.8745, R=0.8594, respectively), the prediction of ammonium nitrogen and total kalium content were acceptable (SEP%=23.2595%, 10.1516%), and the calibration model for nitric nitrogen had the worst performance. The present study indicated that portable AOTF-NIR spectrometer could be used to measure the nutrient parameters of soil.

New Hybrid Algorithm for Maintaining Multivariate Quantitative Calibrations of a Near-Infrared Spectrometer

2002 ◽  
Vol 56 (5) ◽  
pp. 605-614 ◽  
Author(s):  
Christine M. Wehlburg ◽  
David M. Haaland ◽  
David K. Melgaard ◽  
Laura E. Martin
Keyword(s):  
Least Squares ◽  
Real Time ◽  
Hybrid Model ◽  
Hybrid Algorithm ◽  
Near Infrared ◽  
Multivariate Calibration ◽  
Calibration Model ◽  
Spectral Variation ◽  
Calibration Data

Our newly developed prediction-augmented classical least-squares/partial least-squares (PACLS/PLS) hybrid algorithm can correct for the presence of unmodeled sources of spectral variation such as instrument drift by explicitly incorporating known or empirically derived information about the unmodeled spectral variation. We have tested the ability of the new hybrid algorithm to maintain a multivariate calibration in the presence of instrument drift using a near-infrared (NIR) spectrometer (7500–11 000 cm−1) to quantitate dilute aqueous solutions containing glucose, ethanol, and urea. The spectral variations required to update the multivariate models for both short- and long-term drift were obtained using a single representative midpoint sample whose spectrum was repeatedly measured during collection of calibration data and during collection of separate validation sample spectra on three subsequent days. The performance of the PACLS/PLS model for maintaining a calibration was compared to PLS with subset recalibration, a method that has previously been applied to maintenance and transfer of calibration. Without drift corrections, both PACLS/PLS and PLS had poor predictive ability on sample spectra collected on subsequent days. Unlike previous maintenance of calibration studies that corrected for long-term drift only, the PACLS/PLS and PLS models demonstrated the best predictive abilities when short-term drift was also corrected. The PACLS/PLS hybrid model outperformed PLS with subset recalibration for near real-time predictions when instrument drift was determined from the repeat samples closest in time to the measurement of the unknown. Near real-time standard errors of prediction (SEPs) for the hybrid model were comparable to the cross-validated SEPs obtained with the original calibration model.

Fast Evaluation of Pectin Content in Ramie Using NIR Techniques

2011 ◽  
Vol 287-290 ◽  
pp. 2689-2692
Author(s):  
Wei Jiang ◽  
Guang Ting Han ◽  
Yuan Ming Zhang ◽  
Jian Hua Chen
Keyword(s):  
Near Infrared ◽  
Tunable Filter ◽  
Partial Least Square ◽  
Least Square ◽  
National Standard ◽  
Ramie Fiber ◽  
Calibration Model ◽  
Calibration Data ◽  
Fast Evaluation ◽  
Pectin Content

Near-infrared (NIR) prediction model of ramie pectin content was established in this research. Wet chemical analysis method which was based on Chinese national standard was conducted for getting calibration data, and NIR data of 60 ramie samples were collected using acousto-optic tunable filter (AOTF) near-infrared spectrometer. The NIR model of pectin of ramie were derived by partial least square (PLS) regression. Prediction of chemical composition of independent ramie samples showed that R/SEP values of pectin is 17.87. Such NIR calibration model can be utilized by ramie fiber manufacturers and breeding workers, in order to better manage the degumming process and evaluate the quality of ramie varieties.

Remote Raman Microimaging Using an AOTF and a Spatially Coherent Microfiber Optical Probe

1996 ◽  
Vol 50 (8) ◽  
pp. 1007-1014 ◽  
Author(s):  
H. Trey Skinner ◽  
Thomas F. Cooney ◽  
S. K. Sharma ◽  
S. M. Angel
Keyword(s):  
High Power ◽  
Near Infrared ◽  
Fiber Optic ◽  
High Spatial Resolution ◽  
Optical Probe ◽  
Tunable Filter ◽  
Line Of Sight ◽  
Phase Boundaries ◽  
Optical Fiber Bundle ◽  
Clear Line

A fiber-optic Raman microimaging probe is described that is suitable for acquiring high-spatial-resolution Raman images in sampling situations with no clear line of sight. A high-power near-infrared diode laser combined with an acousto-optic tunable filter and a spatially coherent optical fiber bundle allow fluorescence-free Raman images of remotely located samples to be acquired at distances up to several meters. The feasibility of this technique is demonstrated with Raman images of (1) a pellet containing a mixture of a highly scattering sample, bis-methylstyrylbenzene (BMSB), KCl, and graphite, and (2) a partially graphitized diamond. These images clearly show phase boundaries over an area of approximately 0.1 mm2 with ∼4-μm resolution.

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