System for measuring carbon component contained in particulate matter

Abstract

In this system, the carbon component of atmospheric particulate matter (PM2.5) is measured by: heating a sample in a first oven under such conditions as to fractionate the carbon component into carbon fractions; completely converting each carbon fraction into carbon dioxide gas in a second oven; and then measuring the amount of carbon dioxide gas in the carbon fraction precisely. In the system, the problem that a TCD detector cannot measure a low-concentration fraction is solved by using a combustion gas in a non-diluted state, though a combustion gas diluted 150-fold is used in a conventional elemental analyzer. Thus, the present invention develops an international standard instrument in which one standard sample is used and which enables simple standardized measuring acceptable to The International System of Units (SI).

Claims

1. An analysis measurement method, in a combustion type analysis measurement system for measuring a carbon component of a fine particulate matter comprising a first furnace, a second furnace, a combustion tube arranged over the first furnace and the second furnace and having a metal catalyst filled in a portion corresponding to the second furnace, and a TCD detector, the method comprising: a step a) for thermally separating organic carbon by heating a sample including the fine particulate matter in the combustion tube to a temperature from 120 C. to 550 C. corresponding to an organic carbon fraction, and thermally separating elemental carbon by heating the sample to a temperature not less than 550 C. corresponding to an elemental carbon fraction while adding oxygen in the first furnace, a step b) for adding oxygen to the sample and heating the metal catalyst filled in the combustion tube in which the sample and oxygen pass through at a temperature from 550 C. to 1050 C. to oxidize the carbon component completely to CO.sub.2 in the second furnace, and a step c) for measuring CO.sub.2 produced by completely oxidizing a low carbon-containing organic compound standard sample whose carbon content is known by heating in the first furnace and oxidizing in the second furnace as in steps a) and b), making a calibration line that is a relational expression between an electric signal output from the TCD detector and the carbon content of the low carbon-containing organic compound standard sample, and measuring an amount of the carbon component of the fine particulate matter with the TCD detector based on the calibration line.

2. A combustion type analysis measurement system for measuring a carbon component of a fine particulate matter, comprising: a combustion tube arranged over a first furnace and a second furnace and having a metal catalyst filled in a portion corresponding to the second furnace, a first furnace for thermally separating organic carbon by heating a sample including a fine particulate matter in the combustion tube to a temperature from 120 C. to 550 C. corresponding to an organic carbon fraction, and thermally separating an elemental carbon by heating the sample to a temperature not less than 550 C. corresponding to an elemental carbon fraction while adding oxygen, and a second furnace for adding oxygen to the sample and heating a metal catalyst filled in said combustion tube in which the sample and oxygen pass through at a temperature from 550 C. to 1050 C. to oxidize the carbon component completely to CO.sub.2, and a TCD detector for measuring an amount of the carbon component of the fine particulate matter by first measuring CO.sub.2 produced by completely oxidizing a low carbon-containing organic compound standard sample whose carbon content is known by heating in the first furnace and oxidizing in the second furnace, making a calibration line that is a relational expression between an electric signal output from the TCD detector and the carbon content of the low carbon-containing organic compound standard sample, and measuring the amount of the carbon component of the fine particulate matter with the TCD detector based on the calibration line.

3. The combustion type analysis measurement system according to claim 2, further comprising a TCD detector for measuring moisture of the sample by first measuring moisture produced by making a low moisture-containing organic compound standard sample whose moisture content is known by heating in the first furnace and oxidizing in the second furnace, making a calibration line that is a relational expression between an electric signal output from the TCD detector for measuring moisture of the sample and the moisture content of the low moisture-containing organic compound standard sample, and measuring the amount of moisture of the fine particulate matter with TCD detector for measuring moisture of the sample based on the calibration line.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a system constitution in an analysis device of the present invention;

(2) FIG. 2 is a constitution of the carbon fractions and the measurement conditions of the present invention;

(3) FIG. 3 is a diagram showing the calibration line in TCD detector in the analysis device according to the present invention;

(4) FIG. 4 is a diagram showing detected samples at low concentration in TCD detector in the analysis device according to the present invention;

(5) FIG. 5 is a flow chart of fractional determination of carbon fractions of the present invention;

(6) FIG. 6 is another embodiment of a system constitution in an analysis device of the present invention; and

(7) FIG. 7 is another embodiment of a constitution of the carbon fractions and the measurement conditions of the other embodiment.

MODE FOR CARRYING OUT THE INVENTION

(8) As shown in FIG. 1, a system constitution of an analysis device according to a working mode of the present invention is to have combustion tube crossing two ovens or combustion tubes installing on two ovens respectively, wherein a first oven is used for separating carbon fractions and a second oven combusts every carbon fraction completely with enough oxygen, an effect of metal catalyst filled in the combustion tube and high temperature in order to carry out accuracy detection. There is a diffuser before going to a detection system to make the measured gas to proper detection concentration.

(9) Firstly, change of electrical signals before and after passing through a moisture absorption tube is measured by a detector, and H (g) is determined due to a calibration line obtained with organic compound standard samples in advance.

(10) Next, change of electrical signals before and after passing through an absorption tube for carbon dioxide gas is measured by a detector, and C (g) is determined due to a calibration line obtained with organic compound standard samples in advance similarly. A suction pump is installed at an end thereof as a constant speed device.

Working Example No. 1

(11) As shown in FIG. 2, setting temperatures of the carbon fractions and analysis atmosphere are determined and separated in the first oven, and the carbon components are made to carbon dioxide gas by enough oxygen amount, metal catalyst and high temperature combustion in the second oven. Every carbon fraction is determined in the same calibration line in the second oven and the total amount of moisture in the measured value is used for correcting weight of the sample. The total value of every carbon fraction matches the total amount of carbon measured in the case that the sample enters directly into the second oven. Even if the carbon fractions are omitted, organic carbon and inorganic carbon can be measured accurately by measurement of OC, EC and CC.

(12) As shown in FIG. 3a, the calibration line was made by using authenticated organic compound standard sample. In this working example, the existing elemental analyzer (Yanaco CHN corder MT-6) was used and an elemental analysis standard sample SP-1 made by Kishida Chemical certificated by Standard Sample Committee of Informal Social Gathering for Organic Microanalysis Res. was used, but, if using the standard sample certified internationally, this analysis system is useful as an international standard device.

(13) Though a measuring method for international standard has not been established yet, a guideline for an air quality by WHO is 25 (g/m.sup.3) of a daily average and extremely low value of the carbon component thereof must be measured, but, in a working example shown in FIG. 3b, an elemental analysis standard sample SP-15 made by Kishida Chemical certificated by Standard Sample Committee of Informal Social Gathering for Organic Microanalysis Res. was used similarly, and 5.3 g of carbon was detected, and further, if the diffuser in the method according to the present invention makes low concentration impossible to be measured in existing devices proper, it can achieve detection capability close to FID detector.

(14) The working mode shown in FIG. 4 shows analysis errors verified by using an elemental analysis standard sample SP-9 made by Kishida Chemical certificated by Standard Sample Committee of Informal Social Gathering for Organic Microanalysis Res. by the existing elemental analyzer (Yanaco CHN corder MT-6), the analysis errors are 0.1-0.9 g and 0.1-1.3 g about carbon amount and hydrogen amount (g) respectively. Though this detection is analytical precision about the concentration in the case of attenuating combustion gas with He by 150 mL of the pump, the analysis device according to the present invention uses as a constant speed function by placing the pump for attenuating the combustion gas at the rear of the detector, and the diffuser is installed at the position instead of the pump to make homogeneous but not to attenuate, so that detection in the low concentration can be possible by ability of FID detector.

(15) FIG. 5 shows a flowchart of this working mode. If PM2.5 trapped on the quartz filter enters into the first oven together with the quartz filter, working advances along a program based on the flowchart automatically to obtain C (g) and H (g). Firstly, OC1 is separated at a heating step, and next, oxygen is added enough to be combusted OC1 completely at a high temperature step, and then, OC1 is adjusted to suitable detection concentration at a diffusion step, and finally, by advancing to a detection step, measured value of OC1 can be obtained in a measurement value calculation step.

(16) Subsequently, in the heating step, OC2 is separated, and the working is repeated to the measurement value calculation step. The calibration line is simple because using the same line in every carbon fraction. If N detector is added therein, N can be measured at the same time. If the mass concentration is corrected by obtaining the moisture content from the total amount of hydrogen and mass concentration of PM2.5, there is an advantage to be able to obtain the mass concentration without the trouble for drying accurately.

INDUSTRIAL APPLICABILITY

(17) Environmental problem by PM2.5 is not only domestic, and a lot of PM2.5 flied from neighbor countries is serious in our country and in human health. Though it involves business activity in agriculture or in industry deeply, there is also possibility that analysis of atmosphere dust by the measurement causes new industry. The method that can measure easily according to the invention is useful in the foreign countries as an independent technology and can be disseminated widely.

(18) The method according to the present invention is effective as a means for measurement along the international standard because reliability of the measured value can be proved if reliability of the measured value is measured together with data of the standard samples traced in the suitable different international System of Units SI as a monitor corresponding to the detected amount near the measured value of the sample by using the calibration line using the standard sample traced in the International System of Units SI.

EXPLAIN OF LETTERS OR NUMERALS

(19) 1. The first oven for separation of carbon fractions 2. The second oven for combustion of carbon fractions 3. Combustion tube 4. Sample introduction bar 5. Combustion gas diffuser 6. TCD detector 7. H.sub.2O absorption tube 8. CO.sup.2 absorption tube 9. Magnetic valve 10. Constant-speed suction pump 11. Third furnace (reduction furnace)