AU682193B2 – Method and device for the quantative determination of material in a sample
– Google Patents
AU682193B2 – Method and device for the quantative determination of material in a sample
– Google Patents
Method and device for the quantative determination of material in a sample
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Publication number
AU682193B2
AU682193B2
AU69941/94A
AU6994194A
AU682193B2
AU 682193 B2
AU682193 B2
AU 682193B2
AU 69941/94 A
AU69941/94 A
AU 69941/94A
AU 6994194 A
AU6994194 A
AU 6994194A
AU 682193 B2
AU682193 B2
AU 682193B2
Authority
AU
Australia
Prior art keywords
sample
unit
photoemitting
signal
measurement
Prior art date
1993-06-29
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
AU69941/94A
Other versions
AU6994194A
(en
Inventor
Helmut Hackfort
Georg Hinzen
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.)
Forschungszentrum Juelich GmbH
Original Assignee
Forschungszentrum Juelich GmbH
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.)
1993-06-29
Filing date
1994-06-24
Publication date
1997-09-25
1994-06-24
Application filed by Forschungszentrum Juelich GmbH
filed
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Forschungszentrum Juelich GmbH
1995-01-24
Publication of AU6994194A
publication
Critical
patent/AU6994194A/en
1997-09-25
Application granted
granted
Critical
1997-09-25
Publication of AU682193B2
publication
Critical
patent/AU682193B2/en
2014-06-24
Anticipated expiration
legal-status
Critical
Status
Ceased
legal-status
Critical
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Classifications
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
G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
G—PHYSICS
G01—MEASURING; TESTING
G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 – G01N31/00
G01N33/22—Fuels, explosives
G01N33/222—Solid fuels, e.g. coal
Description
P:\OPER\MJC69941-94.133- 11/7/9 -1- METHOD W AND DEVICE FOR THE QUANTITATIVE DETECTION OF MATERIAL IN A SAMPLE The present invention concerns a method of and a device for the quantitative detection of material in a sample. The material is in the form of submicrometric particles covered by a photoemitting substance.
Such a method and device would be useful in many applications, for detecting the amount of coal in a fuel that is to be burned for example or the amount of organic material in a foodstuff or other sample.
Obtaining surface-specific information about floating particles by measuring photoemission is known from German 3 422 054 C2.
The procedure comprises the quantitative detection of substances that evaporate off the particles at a specific temperature. The signal detected in the photoemission section of the apparatus is employed as a measure of the amount of material which has precipitated onto the surface of the aerosol.
S
*S S 4U +7 o’ P:\OPER\MJC\I9941-94.133 11197 -2- According to a first aspect of the present invention there is provided a method of quantitatively detecting material in a sample, said material being of a type that can be converted by heat treatment into submicrometric particles covered by photoemitting substances, said method comprising heating the material in the sample to a photoemitting state and subjected while in that state to photoemission measurement, and determining the proportion of material in the sample from the signal obtained from that measurement in conjunction with empirical data obtained from a reference sample containing a previously detected quantity of the material or by using data obtained for the material by calibration.
Research (cf. the discussion of the figures hereinafter) has S 15 demonstrated that there is a direct relationship between the signal obtained from a photoelectric aerosol sensor and the proportion of material in a sample, assuming that the material is covered with a photoemitting substance.
20 To convert it into a photoemitting state it can be practical to first treat the material in the sample mechanically, to grind it for example. It may also be useful to dilute the sample before or during the heat treatment that generates the photoemitting state by adding an appropriate form of non-emitting inert solid.
In an embodiment of the method of the invention an additional i support, in the form of an inert solid, can be added to the S sample before or S WO 95/01563, PCT/DE94/00731. Translation from German 1 during the heat treatment. The additional support is intended 2 to adsorb the substance that generates the signal and is 3 optionally present in the form of a vapor and to make it 4 accessible to measurement.
6 It can also be practical to add a carrier, an inert gas for 7 example, to the sample.
9 If the sample has been properly prepared, the material can be continuously submitted to photoemission measurement and a 11 corresponding continuous result signal obtained.
12 13 If the sample contains more than one photoemitting material, 14 some or all of the sample can be converted into different photoemitting states and submitted to photoemission 16 measurement, with empirical data obtained from corresponding 17 reference samples or corresponding data obtained from 18 calibration being taken into consideration during 19 quantitative detection of the materials.
21 If the material is an organic material and the photoemitting 22 substance that covers the submicrometric particles is a poly- 23 aromatic hydrocarbon, it will be practical to heat the sample 24 to 600 to 1000 o C and preferably to 750 to 850 o C to convert it to a photoemitting state.
I 3 P:\OI’ER\MC\6991-94.133 11 97 -4- The method of detecting the proportion of material in a sample can be employed in technology in various ways.
If measurement is continuous, the empirical signal can be employed as a parameter for controlling or regulating a combustion process.
In another approach to applying the method in accordance with the present invention, the result of the detection of the material can be employed to verify the quality of the sample (a foodstuffs sample for example).
According to a second aspect of the invention there is provided a device for carrying out the method according to claim 1, 15 characterized by a photoemitting sensor that emits an electric empirical signal, a unit upstream of the sensor that generates photoemitting material, an electronic unit downstream of the sensor that determines the proportion of material in the sample from the signal obtained from that measurement in conjunction 20 with empirical data obtained from a reference sample containing a previously detected quantity of the material or by using data obtained for the material by calibration, displaying the resulting value or emitting it in the form of a digital or electric value.
The unit upstream of the sensor can be a unit for heat-treating the sample if the material can thereby be converted into a photoemitting state. When the material is organic, the heattreating unit should be adjustable to a prescribed temperature of 600 to 1000 0
C.
A unit for introducing a non-emitting inert solid and/or a unit for introducing more support can be optionally positioned upstream of the heat-treating unit in the methods hereintofore described.
WO 95/01563, PCT/DE94/00731, Translation from German 1 When the device is employed for continuous detection of the 2 material, an accessory for continuously supplying the sample 3 can be provided and the electronic unit can be designed to 4 continuously output the empirical signal. A control-orregulating unit can for practical purposes be provided 6 downstream of the electronic unit.
7 8 The teaching in accordance with the present invention 9 provides a rapid and reliable device for samples of combustible material or material with a combustible portion.
11 12 The results of sample detection or analysis can be employed 3 with coal for example for product monitoring and for 14 equipment operations and/or process control in harvesting and processing, trade, and power-plant exploitation. Individual 16 coal-dust burners can be directly controlled in accordance 17 with how much coal or coal equivalent is supplied. The 18 combustion process can also be regulated by incorporating 19 exhaust analysis.
21 The sequence will now be described.
22 23 A fluid sample, of coal dust for example, is 24 produced and heated.
5
I
P:\OPER\MJCV69 I1-94.133 1 I7/9 -6- Heat treatment produces an exhaust-gas aerosol covered with poly-aromatic hydrocarbons (PAH) depending on the organic content of sample on the heat (temperature, duration, etc.), and on the composition of the ambient gas.
The poly-aromatic hydrocarbon coverage of the flowing exhaust-gas aerosol is measured by on-line aerosol photoemission.
For convenience the method and device in accordance with the present invention will now be further described with reference to the accompanying drawing, and empirical results of the detection of material in a sample will be provided. However it is to be understood that the particularity of the following 15 description does not supersede the generality of the preceding description. The steps employed in this research are essentially the same as those of the empirical method. No unit for evaluating and comparison and for generating a signal for controlling the process was employed for this research. The
S..
20 procedure of extracting a sample from a process was simulated.
Steps involved in the method
A.
Extraction of a sample during processing or dispersing a sample ee 25 through a carrier air, nitrogen, oxygen, etc.) e 25 through a carrier (air, nitrogen, oxygen, etc.) ,WO 95/01563, PCT/DE94/00731, Translation from German 1 continuously or 2 discontinuously 3 4 continuous or discontinuous forwarding of the sample.
6 B 7 Conditioning of a dusty sample by heat treatment (e.g.
8 exposure to heat, flash drying, or laser) 9 B,1 11 Use of one or more temperatures.
12 13 B.2 14 Conditioning dilution, addition of an inert supplementary aerosol, or drying) of the submicrometric 16 aerosol sample.
17 18 C.
19 Analysis unit (commercial sensor unit)electrostatic filter for absorbing already charged 21 particles, ultraviolet-radiation unit, and 22 electrometer and amplifier.
23 24 D.
Interpretation unit.
7 *WO 95/01563, PCT/DE94/00731, Translation from German 1 In the accompanying drawing, 2 3 Figure 1 illustrates the method of converting a sample by 4 heat treatment and measurement of the submicrometric aerosol.
6 Figure 2 is a schematic illustration of the device for 7 measurement and signal generation.
8 9 Figure 3 is an illustration of the princip?.e of aerosol photoeiission (APE) and of an ultraviolet-irradiation 11 unit.
12 13 Figure 4 is a graph of signal curves obtained by quantitative 14 measurement.
16 Figure 5 is a graph of signal curves obtained by qualitative 17 measurement (where PAS stands for “photoelectric aerosol 18 sensor”).
19 Figure 6 illustrate a device for research to detect material 21 in a sample.
22 23 24 Figure 1 is a schematic illustration representing the conversion of a particle of dust by heat treatment followed 8 I *WO 95/01563, PCT/DE94/00731, Translation from German 1 by measurement of the submicrometric combustion aerosol. The 2 diameter DI of one particle in the sample is originally on the 3 order of 1 to 1000 pm. Heat treatment is accompanied by 4 exposure to temperatures of up to approximately 1000 O C. The result is a submicrometric combustion aerosol with particle 6 diameters DII of approximately 10 to 400 nm. Radiation with 7 ultraviolet light generates an ionizing current
