JPH0517548U - Particulate rate continuous analyzer - Google Patents

Abstract

(57) [Summary] [Purpose] sof, dry soot, sulf in particulates
(EN) Provided is a particulate continuous analysis device capable of continuously performing quantitative analysis by separating ate. [Structure] A sample gas S flowing in a sample channel 1 and a reference gas R flowing in a reference channel 2 from which particulates have been removed are introduced into a heating combustion furnace 6, and these gases are installed in a combustion pipe 25. After contacting the oxidation catalyst formed by twisting strip-shaped platinum, the infrared gas analyzer 7 detects the gas concentration of the combustion gas in both the channels 1 and 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a continuous particulate analyzer for quantitatively analyzing particulates (fine particles such as soot) in exhaust gas from a diesel engine.

[0002]

[Prior Art]

 As a method of measuring particulate matter in the exhaust gas of a diesel engine, a fixed volume of high-temperature exhaust gas discharged from a diesel engine is introduced into the gas flow passage, and a collection filter installed in this gas flow passage is used. A filter collection / balance weighing method is generally known in which particulates are collected, the filter is weighed with a precision balance or the like, and quantitative analysis is performed based on the weight difference from the filter before the particulate collection.

[0003]

[Problems to be solved by the device]

 However, in the above-mentioned filter collection / balance weighing method, the water adsorbed on the filter has a great influence as a measurement error, and therefore it is necessary to perform heat treatment at a temperature at which only the water in the filter is removed.

Further, the particulate matter usually contains a volatile HC component called a sof (soluble organic fraction) which is soluble in an organic solvent, a C component called a dry soot, and a sulfate, B) Sof must be extracted with an organic solvent, and (b) sulfate must be extracted and measured with distilled water or an eluent for ion chromatography. Therefore, it takes a long time to complete all the measurements, and the work itself requires a great deal of skill, so that there is a drawback that the analysis results vary from person to person.

Moreover, the filter that collects the particulates must be removed from the gas flow path, and therefore, there is a disadvantage that continuous measurement cannot be performed.

Therefore, as a method for continuously measuring particulates, an instantaneous particle densitometer (TEOM), which detects a change in mass when collecting particulates in a filter as a change in bending resonance frequency of a pipe or the like, is irradiated with light. However, a heart ridge type smoke meter for measuring the transmittance has been developed.

However, in the above method, it is not possible to measure sof and dry soot separately, and there is a problem that the correlation with the generally used filter collection / balance method is insufficient. There are also many points.

The present invention has been made in consideration of the above-mentioned matters, and its purpose is to make sof, dry soot, and soot during particulate formation with high accuracy in a short time even if not an expert. It is an object of the present invention to provide a continuous particulate analyzer that can separate sulfate and perform quantitative analysis continuously.

[0009]

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the first invention of the particulate continuous analysis apparatus according to the present invention is a sample flow path to which exhaust gas from a diesel engine is supplied at a constant volume and a sample flow path branched from the sample flow path. A reference flow path provided with a filter for collecting particulates contained therein, a combustion tube for heating the sample gas flowing through the sample flow path, and a combustion tube for heating the reference gas flowing through the reference flow path, An analyzer for analyzing combustion gas that has passed through these combustion tubes is provided, and HC, C, S in the sample gas can be determined from the difference in H ₂ O concentration, CO ₂ concentration and SO ₂ concentration in the sample gas and the reference gas. Is a continuous particulate analyzer that is configured to obtain the respective concentrations of the oxidation catalyst installed in the combustion pipe. In Saku-shaped, and is characterized in that configured in a shape twisted.

The second invention is characterized in that at least the inner surface of the combustion tube is formed of an oxidation catalyst material.

[0011]

[Action]

 According to the above characteristic structure, sof, dry soot, and sulfate can be separated for quantitative analysis without the need for treatment such as solvent extraction, and there is no need to use a precision balance or an organic solvent. Therefore, there is no individual difference in the analysis result, and even an unskilled person can perform highly accurate measurement. In addition, since it is possible to continuously measure the exhaust gas emitted from the diesel engine, it is possible to measure the emission characteristics of the particulates during transient operation in real time.

Furthermore, since a combustion tube having a unique structure is used, an output error caused by a difference in flow rate between the sample gas and the reference gas in the analyzer and a change in response speed is eliminated, and high-precision measurement is possible.

[0013]

【Example】

 Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. This corresponds to the first consideration.

FIG. 1 is a schematic diagram showing the structure of a particulate continuous analyzer according to the present invention. In FIG. 1, 1 is a sample in which exhaust gas (sample gas S) from a diesel engine flows in a constant volume. A flow channel 2 is a reference flow channel branched from the sample flow channel 1 at a point A, and the reference flow channel 2 is provided with a collection filter 3 mounted in a filter holder 4 and is connected to the sample gas S. The included party curates are collected here. The collection filter 3 is made of, for example, quartz or Teflon having a small amount of impurities. Reference numeral 5 is a filter holder (dummy) of the same type as the filter holder 4 mounted to make the dead volume the same as that of the reference flow channel 2, and no filter is mounted in this filter holder 5.

Reference numeral 6 denotes a heating and combustion furnace, which is configured to hold a temperature inside the furnace at a predetermined temperature for a certain period of time by a data processing device (not shown) and to perform heating up to about 1000 ° C. ..

Reference numeral 25 is a combustion tube provided in the heating combustion furnace 6, and 24 is an oxidation catalyst provided in the combustion tube 25. Here, a conventional general oxidation catalyst is composed of, for example, an alumina carrier coated with platinum or platinum wool, and when such an oxidation catalyst is used, when the gas is introduced into the combustion pipe, It is considered that the turbulent flow of the gas and the decrease of the flow rate occur, and the output value from the analyzer has an error.

Therefore, in the present invention, as shown in FIG. 2, for example, an oxidation catalyst 24 formed by twisting strip-shaped thin platinum (or copper) is inserted into a combustion tube 25 made of quartz or alumina. As a result, a swirl flow path is formed inside the combustion pipe 25. This increases the contact area between the gas and the oxidation catalyst 24, efficiently oxidizes the particulates and unburned components contained in the gas, and causes almost no turbulent flow of the gas or a decrease in the flow rate in the combustion pipe 25. Disappear. The inside of the combustion tube 25 is heated by the heater 26.

Reference numeral 7 denotes, for example, an infrared ray gas analyzer (hereinafter, simply referred to as a gas analyzer) of a difference measurement method for detecting the combustion gas that has passed through the heating combustion furnace 6. Reference numerals 8 and 9 are flow rate adjusting valves as flow rate control devices for the sample gas S and the reference gas R which flow through the sample flow path 1 and the reference flow path 2 and are supplied to the gas analyzer 7. The sample gas S and the reference gas R can be supplied to the total 7 in synchronization with each other without a time delay. For example, a mass flow controller is used as this flow rate adjusting valve. In addition, 10 is a bypass pump.

As shown in FIG. 3, the gas analyzer 7 has light sources 13 and 14 arranged on one side of a sample cell 11 and a reference cell 12 which have independent optical paths, and has, for example, an H light source on the other side. An H ₂ O detector 15, a CO ₂ detector 16 and a SO ₂ detector 17 for simultaneously detecting a plurality of gases such as ₂ O, CO ₂ and SO ₂ are arranged in optical series with each other. There is. Reference numeral 18 denotes a modulation chopper provided between the cells 11 and 12 and the light sources 13 and 14 and configured to rotate by a drive mechanism (not shown).

Reference numeral 19 is a preamplifier for amplifying the output signals from the detectors 12, 13 and 14, 20 is an arithmetic circuit for arithmetically processing the gas concentration as an output signal, and 27 is a gas concentration display. It is an indicator for.

Referring again to FIG. 1, reference numeral 21 is a flow path for discharging gas from both cells 11 and 12 (see FIG. 2). In the discharge flow path 21, a critical flow venturi 22 and a discharge pump 23 are provided. Are connected in series.

A method for quantitatively analyzing particulates by this analyzer will now be described. A part of the sample gas S flowing through the sample channel 1 is branched into the reference channel 2 at the point A, and the collection filter 3 is collected. When passing through, the contained particulates are removed and become the reference gas R, which is introduced into the heating combustion furnace 6. Then, the remaining sample gas S is directly introduced into the heating combustion furnace 6 through the dummy filter holder 5 as it is.

The inside of the heating and combustion furnace 1 is heated to, for example, about 1000 ° C., CO and HC components are oxidized to CO ₂ and H ₂ O, and S components are also oxidized to SO ₂ . At this time, the combustion gas in both the flow paths 1 and 2 has the same flow rate and the same response speed by the configuration of the oxidation catalyst 24 and the adjustment of the flow rate adjusting valves 8 and 9 described above, respectively, for the sample cell 11 and reference cell It is supplied to the cell 12.

Then, by irradiating the cells 11 and 12 with infrared light from the light sources 13 and 14, the infrared light passing through the cells 11 and 12 is absorbed in the cells 11 and 12 after a predetermined absorption. , H ₂ O detector 15, CO ₂ detector 16, and SO ₂ detector 17, the sample gas S, the difference in concentration of each gas of H ₂ O, CO ₂ , and SO _{2 in} the reference gas R (for example, the sample gas The concentration difference between H ₂ O in the gas S and H ₂ O in the reference gas R. The same applies to CO ₂ and SO _2. )

Here, the atomic ratio of the H and C components can be roughly estimated depending on the type of exhaust gas, that is, the type of fuel. Therefore, the relational expression shown in the following formula 1 and the H ₂ O concentration detected by the detectors 15, 16 and 17 (difference in H ₂ O concentration in the sample gas S and the reference gas R), CO ₂ concentration (sample gas S and difference of the CO ₂ concentration in the reference gas R), SO ₂ concentration (the sample gas S and a number of 1 to SO difference ₂ concentration) in the reference gas R, b, c, that C (dry soot), HC (Sof), and the concentration of S can be obtained.

[0026]

[Equation 1]

In the above formula 1, a is a C concentration, that is, a dry soot concentration, b is an HC concentration, that is, a so f concentration, c is an S concentration, and x is H at a sof preset according to the type of fuel. The ratio of the number of atoms with C, α and β, are the concentrations of oxygen that are in excess of a, b, and c.

That is, the concentrations of sof, dry soot, and sulfate in the diesel engine exhaust gas can be separately determined from the atomic ratio x of H and C and the concentrations of H ₂ O, CO ₂ , and SO _2. .

FIG. 4 shows a second embodiment of the present invention, which corresponds to the second invention.

In the figure, 28 is a combustion tube formed in a cylindrical shape from an oxidation catalyst material such as platinum (or copper), and the oxidation catalyst 28 itself is configured so as to also serve as a combustion tube. As a result, similar to the first embodiment, the particulates and unburned components contained in the gas are efficiently oxidized, and the turbulent flow of the gas and the reduction of the flow rate hardly occur in the pipe. Here, the cylindrical tube may be made of quartz or alumina and the inner surface thereof may be coated with platinum (or copper) as an oxidation catalyst.

The other configurations are not different from those of the first embodiment, and the description thereof will be omitted.

As described above, in the present embodiment, the case where the infrared gas analyzer of the difference measurement method is used as the analyzer has been described, but the present invention is not limited to this, and the description and drawings of Japanese Utility Model Application No. 60-85105, for example, can be used. A fluid modulation type infrared gas analyzer for multi-component measurement as disclosed may be used.

[0033]

[Effect of the device]

 As described above, according to the present invention, it is possible to separate sof, dry soot, and sulfate for quantitative analysis without the need for pretreatment such as solvent extraction, and to carry out quantitative analysis. Since it is not necessary to use, there is no individual difference in the analysis results, and even an unskilled person can perform highly accurate measurement. In addition, since it is possible to continuously measure the exhaust gas emitted from the diesel engine, it is possible to measure the emission characteristics of the particulates during transient operation in real time.

Furthermore, since an oxidation catalyst having a unique structure is used, an output error caused by a difference in flow rate between the sample gas and the reference gas in the analyzer and a change in response speed is eliminated, and highly accurate measurement is possible. Become.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a particulate analyzer.

FIG. 2 is a diagram showing a structure of an oxidation catalyst according to a first invention.

FIG. 3 is a diagram schematically showing an infrared gas analyzer.

FIG. 4 is a diagram showing a structure of an oxidation catalyst according to a second invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sample flow path, 2 ... Reference flow path, 3 ... Filter, 6 ... Heating combustion furnace, 7 ... Gas analyzer, 24, 28 ... Oxidation catalyst, 25 ... Combustion tube.

Claims (2)

[Scope of utility model registration request] 1. A reference flow path comprising a sample flow path to which exhaust gas from a diesel engine is supplied in a constant volume, and a filter branched from the sample flow path to collect particulates contained in the sample gas. When,
A combustion pipe for heating the sample gas flowing through the sample flow passage and a combustion pipe for heating the reference gas flowing through the reference flow passage, and an analyzer for analyzing the combustion gas passing through these combustion pipes are provided. H ₂ O concentration difference, CO ₂ concentration difference, SO ₂
A continuous particulate analyzer for determining the respective concentrations of HC, C, and S in a sample gas from the difference in concentration, wherein the oxidation catalyst installed in the combustion tube is strip-shaped and twisted. A particulate continuous analyzer characterized by having a different shape. 2. A reference flow path comprising a sample flow path to which exhaust gas from a diesel engine is supplied in a constant volume and a filter branched from the sample flow path to collect particulates contained in the sample gas. When,
A combustion tube for heating the sample gas flowing through the sample flow path and a combustion tube for heating the reference gas flowing through the reference flow path, and an analyzer for analyzing the combustion gas passing through these combustion tubes are provided. H ₂ O concentration difference, CO ₂ concentration difference, SO ₂
A particulate continuous analyzer configured to determine the respective concentrations of HC, C, and S in a sample gas from the difference in concentration, wherein at least the inner surface of the combustion tube is formed of an oxidation catalyst material. Curate continuous analyzer.