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WO1998002734A1 - Commande de processus industriel repartie utilisant la spectroscopie a imagerie - Google Patents

Commande de processus industriel repartie utilisant la spectroscopie a imagerie Download PDF

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Publication number
WO1998002734A1
WO1998002734A1 PCT/US1997/012202 US9712202W WO9802734A1 WO 1998002734 A1 WO1998002734 A1 WO 1998002734A1 US 9712202 W US9712202 W US 9712202W WO 9802734 A1 WO9802734 A1 WO 9802734A1
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WO
WIPO (PCT)
Prior art keywords
location
optical
output
raman
imaging spectrometer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1997/012202
Other languages
English (en)
Inventor
Colin J. H. Brenan
Ian Hunter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MIRAGE TECHNOLOGIES
Original Assignee
MIRAGE TECHNOLOGIES
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by MIRAGE TECHNOLOGIES filed Critical MIRAGE TECHNOLOGIES
Publication of WO1998002734A1 publication Critical patent/WO1998002734A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28—Investigating the spectrum
    • G01J3/2889—Rapid scan spectrometers; Time resolved spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28—Investigating the spectrum
    • G01J3/2823—Imaging spectrometer
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28—Investigating the spectrum
    • G01J3/44—Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/65—Raman scattering
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/85—Investigating moving fluids or granular solids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/85—Investigating moving fluids or granular solids
    • G01N21/8507—Probe photometers, i.e. with optical measuring part dipped into fluid sample

Definitions

  • the present invention relates to systems and methods for providing real time on-line control of processes, such as chemical processes, that are monitored using spectrometers.
  • Typical analysis of petroleum products during the production process involves performing gas chromatography on periodic samples. Although accurate, this process is time consuming, labor intensive and the substantial lag time can result in considerable costs when production errors do occur.
  • a preferred method of analysis would involved real-time and in-line monitoring from a remote location. If accurate, such a monitoring method would allow intelligent process control.
  • Raman spectroscopy has been demonstrated as a viable alternative to mid- or near-IR absorbance/reflectance spectroscopic methods in quantitative assessment of petroleum sample composition.
  • Advances in near-IR laser diode, photosensor and optical filter technologies has resulted in the construction of high optical throughput Raman spectrometers capable of low fluorescent Raman spectral acquisition from petroleum products.
  • these instruments When combined with multivariate statistical analysis, these instruments have been shown to measure the gas oil cetane number and cetane index, the percenl fuel composition for liquid fuel mixtures of unleaded gasolines, super-unleaded gasoline and diesel fuels and the concentrations of benzene and other aromatic compounds.
  • Raman spectroscopic analyses of aviation fuel have determined its general hydrocarbon makeup, aromatic components and additives. Summary of the Invention
  • a system for providing real-time control of a process that is monitored at a plurality of process locations by spectrometric techniques.
  • the system utilizes an imaging spectrometer having an optical image input and a spectral image output.
  • a plurality of modules are employed; one module is disposed in each process location.
  • Each module has an illumination source for illuminating such location; a collector for collecting light that has been scattered at such location and directing such light to a collector output; and an optical fiber arranged to provide optical communication from the collector output to a pixel location of the optical image input of the imaging spectrometer.
  • an optical transducer is placed in communication with the spectral image output of the imaging spectrometer.
  • the optical transducer provides as an output, spectral data, associated with each pixel location of the optical image input and therefore associated with each process location, for the purpose of process control.
  • the spectrometer may, but need not necessarily, be a Raman spectrometer. Indeed, a plurality of types of spectrometry may be employed simultaneously for implementing the process control.
  • Fig. 1 is a schematic of a preferred embodiment of system in accordance with the present invention.
  • Fig. 2 is a schematic showing how a plurality of systems of a type such as shown in Fig. 1 may be used for control of more complex or more distributed processes.
  • a system for providing real-time control of a process that is monitored at a plurality of process locations by spectrometric techniques.
  • the present embodiment for example may be used, for example, for real-time in - line monitoring of fuel composition based on fiber-optic Raman spectroscopic detection and analysis from multiple points distributed at critical junctures in the process stream.
  • the output of the monitoring system could then be used as one parameter for feedback control of the petroleum refining or blending process.
  • the system design is self-contained and modular for flexible and easy reconfiguration or upgrade to satisfy new measurement requirements as they arise.
  • a real-time computer-based data acquisition system acquires and processes the spectrochemical information before submission in a standardized format to the global process controller.
  • illumination of a molecular ensemble with a beam of monoenergetic optical photons having an energy outside any molecular absorption bands results in a large number of elastically (Rayleigh) scattered photons.
  • a small fraction of the incident photons, however, are inelastically (Raman) scattered by inducing transitions between vibrotational molecular energy states in which the molecular polarizability and the final state wavefunction belong to the same symmetry group.
  • the scattered light spectrum consists of a dominant Rayleigh line at energy offsets equal to the energy gained or lost by the Raman scattered photons that corresponds to :he energy difference between the initial and final molecular states, raman line intensities are dependent on the magnitude of the derived molecular polarizability tensor and the number of molecules in the initial energy state.
  • Confocal Raman spectroscopic imaging (and Raman spectroscopic imaging in general) is advantageous in many respects and, interestingly, spectroscopic imaging principles can be applied here. Compare the confoc al Raman spectroscopic and reflected intensity images acquired from a mixtL.re of two optically similar yet chemically distinct substances, potassium sulfate (K 2 S0 4 and NaHC0 3 . The dominant Raman spectral lines used to discriminate K 2 S0 4 from NaHC0 3 are 960 cm “1 and 1040 cm “1 , respectively.
  • Fig. 1 are shown the two subsystems utilized in accordance with the embodiment referred to above: one for illumination and collection of the Raman scattered light from the sample (the Illumination/Collection (I/C) modules 11) and the second for Raman spectral analysis, namely, a Raman interferometric spectrometer 12.
  • the sample resides inside a pipe 13 but in actuality the sample can be located anywhere accessible to an optical fiber bundle.
  • Each subsystem is designed to be self- contained and modular for easy extension of the sensing network and for flexible reconfiguration to meet the changing measurement requirements of the user.
  • An I/C module 11 contains a miniature distributed Bragg reflector (DBR) near-IR laser diode operating at approximately 850 nm with an output power >50 mW to illuminate through a lens /window the liquid flowing in the pipe.
  • DBR distributed Bragg reflector
  • a new technological development in diode lasers, the DBR laser is preferred over the more common index-guided diode laser because a DBR laser exhibits no mode hopping, shows no frequency hysteresis as a function of both temperature and current changes and emits substantially less broadband radiation.
  • a near-IR wavelength laser diode is selected to minimize interfering fluorescent emission from the liquid and to take advantage of the maximal quantum efficiency in this wavelength range of the silicon photosensor that detects the scattered Raman light.
  • Light backscattered from the liquid in pipe 13 is collected and input into a group of fused silica fibers 14 tapped from a larger fiber bundle 15 that acts as an optical "bus" to transmit the light from each module to the imaging Raman spectrometer 12.
  • the fiber bundled output illuminates through a cylindrical lens 16 the spectrometer after removal of the source illumination component by a laser line filter 17.
  • a filter could also be located in each I/C module 11 to minimize induced optical fiber fluorescence if that proves to be problematic.
  • the Raman spectrometer 12 shown is one based on ta Michelson-type interferometer.
  • Light from the fiber bundle 15 is amplitude-divided by the beamsplitter 121, reflected from a mirror 122 (at a distance determined by mirror control 124) and recombined by the same beamsplitter 121 to be imaged onto an array 123 of photosensors. Moving one 6
  • the Raman imaging spectrometer 12 allows simultaneous multiplex detection of Raman signals from multiple 1/ C modules 11 linked to the spectrometer 12 via the optical fiber bundle 15.
  • the Raman Michelson imaging spectrometer depicted in Fig. 1 Its optical configuration is such that each group of optical fibers 14 carrying Raman scattered light from a given module 11 illuminates a spatially localized group of pixels on the CCD camera after propagation through interferometer. Each module 11, therefore, is assigned a correlate spatial position on the CCD photosensor array 123. Scanning the interferometer over a given number of optical lags records the scattered light autocorrelation function (interferogram) for each module 11.
  • the recorded interferograms are then input to computer 18 and the Raman spectral signal from each module is recovered on taking the digital Fourier transform of each measured autocorrelation function.
  • This spatially multiplexed approach therefore constructs Raman spectral "images" of the process where each "pixel” in the spectral "image” corresponds to a different sensor 11 located at a different point in the process stream.
  • All signal processing and command and control system functions are implemented with a computer 18 integrated with a suitable data acquisition system.
  • a computer 18 integrated with a suitable data acquisition system.
  • I/C modules 11 per Raman spectrometer 12.
  • FIG. 2 to handle more spectral measurements of the process, it is possible to utilize a plurality of spectrometer systems 21, each with a spectrometer module 12 and associated I/C modules 11.
  • the spectral output from each spectrometer module 12 is placed on a high speed bus 23 used for communication between computer 22 and each spectrometer system 21.
  • the particular architecture and design for bus 23 and computer 22 are not a part of the present invention.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)

Abstract

Système permettant de commander un processus industriel en temps réel. Le processus est contrôlé au niveau de plusieurs emplacements. A chaque emplacement, il est éclairé par une source d'éclairage, et la lumière diffusée est captée et dirigée, par l'intermédiaire d'un ensemble de fibres optiques, sur un emplacement de pixel à l'entrée d'un spectromètre d'imagerie. Des informations spectrales associées à chaque emplacement du processus sont ensuite utilisées pour la commande des processus.
PCT/US1997/012202 1996-07-15 1997-07-15 Commande de processus industriel repartie utilisant la spectroscopie a imagerie Ceased WO1998002734A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US2177596P 1996-07-15 1996-07-15
US60/021,775 1996-07-15

Publications (1)

Publication Number Publication Date
WO1998002734A1 true WO1998002734A1 (fr) 1998-01-22

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Application Number Title Priority Date Filing Date
PCT/US1997/012202 Ceased WO1998002734A1 (fr) 1996-07-15 1997-07-15 Commande de processus industriel repartie utilisant la spectroscopie a imagerie

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100390945B1 (ko) * 2000-12-29 2003-07-10 주식회사 하이닉스반도체 플래쉬 메모리 셀의 소거 속도 측정 회로
EP1495317B1 (fr) * 2002-04-13 2015-11-18 Endress + Hauser Conducta GmbH + Co. KG Systeme de determination spectrometrique d'une grandeur de processus physique et/ou chimique

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2245971A (en) * 1990-06-22 1992-01-15 Nat Res Dev Spectrometers
US5139334A (en) * 1990-09-17 1992-08-18 Boston Advanced Technologies, Inc. Hydrocarbon analysis based on low resolution raman spectral analysis
US5412465A (en) * 1993-08-02 1995-05-02 The United States Of America As Represented By The United States Department Of Energy Method for verification of constituents of a process stream just as they go through an inlet of a reaction vessel

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2245971A (en) * 1990-06-22 1992-01-15 Nat Res Dev Spectrometers
US5139334A (en) * 1990-09-17 1992-08-18 Boston Advanced Technologies, Inc. Hydrocarbon analysis based on low resolution raman spectral analysis
US5412465A (en) * 1993-08-02 1995-05-02 The United States Of America As Represented By The United States Department Of Energy Method for verification of constituents of a process stream just as they go through an inlet of a reaction vessel

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100390945B1 (ko) * 2000-12-29 2003-07-10 주식회사 하이닉스반도체 플래쉬 메모리 셀의 소거 속도 측정 회로
EP1495317B1 (fr) * 2002-04-13 2015-11-18 Endress + Hauser Conducta GmbH + Co. KG Systeme de determination spectrometrique d'une grandeur de processus physique et/ou chimique

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