JP2015222222A - Method of collecting exhaust gas component by use of on-line derivatization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of collecting an exhaust gas component by use of on-line derivatization which stably analyzes a gas component, in collecting the gas component by use of a collecting material for gas analysis.SOLUTION: A pre-stage collecting material 20 including a sampling probe 18 arranged in an exhaust gas flow and filled with absorbent with impregnated derivatization reaction, is connected to a post-stage collecting material 21 filled with absorbent, on the subsequent stage. The exhaust gas is sucked through the sampling probe 18. The pre-stage collecting material 20 collects a gas component having a hydroxy group, as derivative, by silanization, acylation, or alkylation. The post-stage collecting material 21 collects a gas component passing through the pre-stage collecting material 20.

Description

  The present invention relates to a method for collecting exhaust gas components using on-line derivatization for analyzing gas components contained in diesel exhaust gas.

Diesel exhaust gas is a mixture of particulate matter and gaseous matter. The particulate matter is referred to as DEP (Diesel Exhaust Particulate), and is solid particles (PM) made of carbon and ash, and includes SOF (Soluble Organic Fraction) and the like aggregated and adsorbed on the solid particles. The gaseous substances are mostly N ₂ , CO ₂ , and O ₂ , but contain NOx and SOx harmful components and a wide variety of hydrocarbons due to fuel combustion.

  Diesel exhaust gas aftertreatment devices include DPF (Diesel Paticulate Filter) that collects PM and DEP, DOC (Diesel Oxidation Catalyst) that oxidizes HC, NOx storage reduction catalyst (LNT) that removes NOx and SOx. An aftertreatment system using Lean NOx Trap or NSR (NOx Strage Reduction), urea SCR (Selective Catalystic Reduction), etc. has been put into practical use.

  However, hydrocarbons in gas components include components that cannot be removed by diesel exhaust gas aftertreatment equipment, and among these, as gas components contained in PRTR (Pollutant Relese and Transfer Register) targets , Formaldehyde, benzene, benzaldehyde, 1,3-butadiene, toluene, trimethylbenzene, styrene, xylene, ethylbenzene, acetaldehyde, acrolein, etc. Among them, formaldehyde, 1,3-butadiene, benzene, which are said to have a high carcinogenic risk Quantitative analysis of acetaldehyde has become an important issue.

  Conventionally, GC / MS (gas chromatograph mass spectrometer) and GC / FID (gas chromatograph hydrogen ionization detector) are used for analysis of gas components in exhaust gas. In order to perform analysis with these analyzers, it is necessary to collect exhaust gas, and there are a method of collecting in a bag and a method of collecting in a collecting material.

  However, the method of collecting in a bag has a limit in exhaust gas capacity and is not suitable for quantitative analysis.

  The method of collecting the gas component in the collection material is to fill the collection material with an adsorbent, suck the exhaust gas through the collection material for a certain period of time, and adsorb the gas component in the exhaust gas to the adsorbent. After the collection, this collection material is set in GC / MS, and the gas component adsorbed by the adsorbent in the collection material is heated and desorbed to analyze the gas component.

  A gas component is adsorbed by the collecting material and analyzed by GC / MS or GC / FID, whereby a quantitative analysis of the gas component with high accuracy can be performed.

International publication WO2011 / 065381 JP 2010-164467 A JP 2010-151607 A

  However, in the exhaust gas, aldehydes and carboxylic acids are unstable components that can be thermally decomposed or altered because they have a carbonyl group (C = O) or a hydroxy group (OH) in the molecule. Yes, even if components change during collection or are collected, stable analysis is difficult because they are exposed to high temperatures when introduced into the analyzer.

  That is, as the adsorbent used for the collection material, a physical adsorbent such as Tnax TA (registered trademark) or activated carbon made of porous polymer beads is used, but the component to be collected is applied to the collection material by physical adsorption. Since it is held, there is a problem that it is not possible to prevent changes in components during collection or when exposed to high temperatures in order to be completely vaporized at the stage of introduction into the analyzer.

  Therefore, an object of the present invention is to solve the above-mentioned problems, collect gas components using a collection material, and perform gas analysis of the exhaust gas using on-line derivatization that enables stable analysis of the gas components. It is in providing the collection method of a gas component.

  In order to achieve the above object, the present invention is directed to a sampling probe that is exposed to a sampling probe in an exhaust gas flow, and a pre-stage collecting material that is filled with an adsorbent impregnated with a derivatization reaction. Connect the downstream collector filled with the agent, suck the exhaust gas through the sampling probe, and in the upstream collector, the gas component having a hydroxy group as a derivative by silylation or acylation or alkylation reaction An exhaust gas component collecting method using on-line derivatization, characterized in that a gas component that has been collected and broke through a preceding collection material is collected by a subsequent collection material.

  The adsorbent packed in the pre-stage collection material is impregnated with a derivatization reagent consisting of a trimethylsilylating agent, an acylating agent or an alkylating agent diluted in a solvent, and this is dried in a helium stream. It is preferable that a pre-stage collecting material is formed.

  The adsorbent used for the pre-stage collection material and the post-stage collection material is preferably composed of porous polymer beads and a carbon-type adsorbent.

  Add a certain amount of internal standard substance for derivatization efficiency correction to the pre-collecting material, add an internal standard substance for quantitative analysis during gas analysis, and correct derivatization efficiency during GC / MS analysis The internal efficiency of the internal standard substance used for the analysis is corrected for the collection efficiency of the gas component adsorbed and derivatized by the pre-stage collection material. It is preferable to perform a quantitative analysis.

  When the exhaust gas is sucked through the sampling probe, it is preferable to remove the DEP content in the exhaust gas through the filter and suck the exhaust gas from which the DEP content has been removed with the sampling probe.

  According to the present invention, a sampling probe is connected to a pre-stage collector in which an adsorbent is impregnated with a derivatization reaction, and a post-stage collector made of an adsorbent is connected to a subsequent stage to collect gas components in the exhaust gas. Therefore, an excellent effect is achieved in that accurate analysis can be performed even with a thermally unstable gas substance.

It is the schematic which shows one embodiment of this invention. It is a figure which shows the detail of the front | former stage collection material shown in FIG.

  A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 denotes an exhaust gas introduction cylinder for introducing diesel exhaust gas, which is branched and connected from an exhaust gas pipe (not shown) of the diesel engine.

  The exhaust gas introduction cylinder 10 is configured by connecting an introduction part 11, a main body part 12 and a discharge part 13 with flanges 14 and 15, and a particle collection filter for collecting DEP between the flanges 14 and 14 on the introduction side. 16 is provided, and a backup particle collecting filter 17 is provided between the flanges 15 on the discharge side.

  An exhaust gas sampling probe 18 is provided in the main body 12 so as to penetrate the trunk of the main body 12. The sampling probe 18 on the outside of the main body 12 has a front-stage collecting material 20, and a rear-stage collecting material 20. The collecting material 21 is connected in a detachable manner.

  Although details are omitted on the downstream side of the post-stage collection material 21, it is connected to a pump, and exhaust gas can be sucked through the sampling probe 18 by driving the pump.

  As shown in FIGS. 2 (a) and 2 (b), the pre-stage collection material 20 is filled with an adsorbent 22 impregnated with a derivatization reaction in a glass tube 24. 25 and sealed.

  More specifically, as the adsorbent 22, weakly polar porous polymer beads (Tnax TA) based on 2.6-Diphenyl-p-phenylene Oxide and carbon-based (Carbotrap-based: registered trademark) are used. After filling 100 to 150 mg in a glass tube 24 (for example, diameter 7 mmφ (inner diameter 4 mmφ), length L50 mm) as in a), as shown in FIG. Dilute derivatizing reagents such as trimethylsilylating agent, acylating agent and alkylating agent with a solvent, impregnate them, add a certain amount of internal standard substance for derivatization efficiency correction, and then dry under He flow Let the pre-collection material 20 be.

  As the trimethylsilylating agent, BSTFA (N, O-bis (trimethylsilyl) trifluoraacetamide) + TMCS (Trimethylchlosilan), BSTFA or the like is used, as the acylating agent, acetic anhydride or the like is used, and as the alkylating agent, PFBHA (pentafluoro) is used. Benzoylhydroxylamine hydrochloride) and the like are used. The derivatization reagent diluted with acetonitrile to a concentration of about 1 mM is used to impregnate the adsorbent 22 with 2 to 4 ml.

  Further, as an internal standard substance for derivatization efficiency correction, a certain amount of oxalic acid d-form is added.

  The drying under the He stream is impregnated with the derivatization reagent and dried, and then the internal standard substance is added and then dried again under the He stream. You may dry under airflow.

  The post-stage collector 21 is formed by filling 100 to 150 mg of the same adsorbent as the pre-stage collector 20 and sealing both sides with quartz wool 25 and 25.

  The upstream collection material 20 is detachably connected to the sampling probe 18, and the downstream collection material 21 is detachably connected to the upstream collection material 20, and a pump (not shown) is connected to the downstream collection material 21. The suction pipe connected to) is detachably connected.

  The exhaust gas is collected by flowing exhaust gas into the exhaust gas introduction cylinder 10 at 100 L / min (50 to 150 L / min) at a temperature of 35 ° C. (50 ° C. or less), and 0.1 L from the sampling probe 18 with a pump For example, the sampling time is 15 to 30 minutes, the gas component is collected in the upstream collection material 20, and the gas component that broke through the upstream collection material 20 is collected in the downstream collection material 21. .

At the time of this collection, since the adsorbent 22 of the pre-stage collection material 20 is impregnated with a derivatization reagent, gas components having OH groups or CO groups such as thermally unstable oxalic acid are silylated. It is derivatized by (—OSiR ³ ) or acylation (—OC (═O) R) reaction or alkylation (═N—OCH ₂ —C ₆ F ₅ ) and collected in a stable state.

  In this way, thermally unstable components are converted into thermally stable substances by derivatization reactions (silylation reactions, acylation reactions, alkylation reactions) at the collection stage, enabling stable analysis. be able to. At the same time, the pre-collecting material 20 can also collect gas components that do not require derivatization. These derivatizations can make alcohols, amides, amines, amino acids, carboxylic acids, enols, phenols, etc. free of steric hindrance into stable forms. Further, the gas component that broke through the upstream collecting material 20 can be collected by the downstream collecting material 21.

  The pre-stage collection material 20 and the post-stage collection material 21 that collected the gas component are then set in the heat desorption type GC / MS, and the gas component adsorbed by the adsorbent in the collection material is desorbed by heating. Analyze gas components.

  At this time, an internal standard material (such as silylated oxalic acid) for quantitative analysis is added to the pre-collecting material 20, and the results of spectral analysis of the internal standard material for derivatization efficiency correction are performed during GC / MS analysis. Then, the collection efficiency of the gas component adsorbed and derivatized by the pre-stage collection material is corrected, and the corrected gas component is quantitatively analyzed based on the spectrum analysis result of the internal standard substance for quantitative analysis. By this quantitative analysis, the amount of exhaust gas that has passed through the upstream collection material 20 and the downstream collection material 21 is known, and the concentration of each gas component in the exhaust gas can be determined from the corrected gas component amount.

  The DEP collected by the particle collection filters 16 and 17 detects the amount of PM, and performs GC / MS analysis on the SOF that has adhered and condensed on the PM.

  As described above, the present invention enables simultaneous collection of gas components and particles, which is very useful for grasping the properties of particles and gases contained in the exhaust gas.

  Since the derivatization reaction is very fast, the derivatization is almost completed when the exhaust gas enters the pre-stage collection material 20, so that even a component that is very easily decomposed can be collected in a stable state. become.

10 Exhaust gas introduction cylinder 18 Sampling probe 20 Pre-stage collection material 21 Post-stage collection material

Claims (5)

  A sampling probe is faced in the exhaust gas flow, and a pre-stage collection material filled with an adsorbent impregnated with a derivatization reaction and a post-stage collection material filled with an adsorbent in the subsequent stage are connected to the sampling probe. Then, the exhaust gas is sucked through the sampling probe, and the gas component having a hydroxy group is collected as a derivative by silylation, acylation or alkylation reaction with the pre-stage collection material, and the pre-stage collection material is broken through. A method for collecting exhaust gas components using on-line derivatization, wherein the collected gas components are collected by a post-stage collecting material.   The adsorbent packed in the pre-stage collection material is impregnated with a derivatization reagent consisting of a trimethylsilylating agent, an acylating agent or an alkylating agent diluted in a solvent, and this is dried in a helium stream. The method for collecting exhaust gas components using on-line derivatization according to claim 1, wherein the pre-stage collecting material is formed.   The method for collecting exhaust gas components using on-line derivatization according to claim 1 or 2, wherein the adsorbent used for the pre-stage collection material and the post-stage collection material comprises porous polymer beads and a carbon-type adsorbent.   Add a certain amount of internal standard substance for derivatization efficiency correction to the pre-collecting material, add an internal standard substance for quantitative analysis during gas analysis, and correct derivatization efficiency during GC / MS analysis The internal efficiency of the internal standard substance used for the analysis is corrected for the collection efficiency of the gas component adsorbed and derivatized by the pre-stage collection material. The method for collecting exhaust gas components using on-line derivatization according to claim 2, wherein quantitative analysis is performed.   5. When exhaust gas is sucked through the sampling probe, DEP content in the exhaust gas is removed through the exhaust gas through a filter, and the exhaust gas from which the DEP content has been removed is sucked by the sampling probe. A method for collecting exhaust gas components using on-line derivatization according to claim 1.

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