Compact TOC analyzer with integrated carrier gas preparation

Abstract

The invention relates to a compact TOC analyzer with integrated carrier gas preparation. A method for generating a purge carrier gas for a TOC analyzer (1) from ambient air wherein the method comprises: directing a carrier gas consisting of ambient air from an inlet (2) of the TOC analyzer (1) to a pre-chamber (6) and a # imgabs0 # absorber (7) by at least one filter (3), at least one flow sensor (4), a humidifier (5); in the pre-combustion chamber (6), organic impurities in the air are oxidized to # imgabs 1 # at a temperature of 680 DEG C or higher, and the # imgabs 2 # absorber (7) preferably includes soda lime that adsorbs # imgabs 3 # generated in the pre-combustion chamber.

Description

Technical Field

[0001] The present invention relates to a TOC analyzer with integrated carrier gas preparation, a method for preparing a carrier gas from ambient air, and a method for measuring the TOC content using the TOC analyzer according to the present invention. Background Art

[0002] When determining the total organic carbon (TOC) of a liquid sample, the organic components are oxidized to form . In a liquid sample, the carbon contained therein is usually converted to carbon dioxide in a wet chemical manner or using UV or combustion methods. The sample is burned in a high-temperature furnace at 680 °C - 1200 °C. In the combustion method (especially at a temperature of <1000 °C), a catalyst is often used to ensure complete oxidation. Thus, in an aqueous sample, in addition to carbon dioxide and other combustion gases, water vapor also appears and is usually condensed and separated from the carbon dioxide gas after combustion. Before the carbon dioxide gas enters the analysis unit, sometimes filters and absorbers or adsorbers are used to remove dust, aerosols, and other gas components from the carbon dioxide gas. With the help of a carrier gas, the resulting is guided to the detector, where is measured.

[0003] Then, the organic carbon initially present in the sample can be directly derived from the measured amount. When analyzing TOC, the carrier gas used in the analyzer does not need to be, otherwise this will distort the measurement result.

[0004] Oxygen or a mixture of oxygen and nitrogen, (treated) compressed air, and ambient air are used as the carrier gas, where this air must be purified of organic compounds to be free of . When using ambient air, it must be free of or other carbon-containing compounds, preferably organic compounds. The carbon content is determined by means of a non-dispersive infrared (NDIR) sensor.

[0005] The supply via an external gas source depends on a central gas source on the one hand, and the central gas source is not available everywhere where the analyzer is used. The alternative of using an external gas supply with portable cylinders is expensive.

[0006] When using ambient air, the air is treated outside the analysis device. The external air treatment requires a large amount of space and expensive compressors. Summary of the Invention

[0007] Based on the prior art, the object of the present invention is to provide a compact TOC analysis device that does not require the use of an external carrier gas source.

[0008] This object is achieved by a TOC analyzer for determining the carbon content of a sample according to the present invention, comprising:

[0009] An inlet for a carrier gas to enter the TOC analyzer, wherein the carrier gas is configured to be guided to a high-temperature furnace via:

[0010] - At least one filter,

[0011] - At least one flow sensor,

[0012] - A humidifier, and

[0013] - A pre-combustion chamber designed as a high-temperature combustion chamber to oxidize organic impurities in the air into ,

[0014] - An absorber, the absorber preferably comprises soda lime,

[0015] - At least one pump,

[0016] wherein

[0017] The high-temperature furnace is designed to evaporate or oxidize the sample at a high temperature to form water vapor and carbon dioxide gas;

[0018] The carrier gas is configured to transport the carbon dioxide gas generated during the oxidation of the sample in the high-temperature furnace to the analysis unit;

[0019] At least one flow sensor and at least one pump are designed to regulate the flow rate of the carrier gas through the high-temperature furnace;

[0020] An injection unit configured to inject a liquid sample into the high-temperature furnace;

[0021] An analysis unit designed to measure the carbon content of the sample based on the carbon dioxide gas generated by the oxidation of the sample; and

[0022] A data processing unit designed to perform the following steps:

[0023] Controlling the carrier gas flow rate by

[0024] At least one pump,

[0025] At least one flow sensor,

[0026] Controlling and / or regulating the injection unit (18), and

[0027] Determining the carbon content of the sample.

[0028] In one embodiment, the introduced carrier gas consists of ambient air.

[0029] In one embodiment, a condensation unit and an acid filter are arranged between the high-temperature furnace and the analysis unit.

[0030] The high-temperature furnace typically operates at 680 - 1,200 °C. According to the method of the present invention, the preferred temperature is 680 °C.

[0031] The condensation unit is designed to condense the water vapor obtained in the high-temperature furnace. The acid filter is designed to remove aerosols from the gas stream.

[0032] In one embodiment, at least one pump is at least one diaphragm pump. In one embodiment, at least one diaphragm pump is designed to achieve a pressure of 400 mbar.

[0033] In one embodiment, the analysis unit includes a non-dispersive infrared (NDIR) sensor.

[0034] In one embodiment, a flow sensor is connected downstream of the filter and the analysis unit.

[0035] The present invention also relates to a method for producing a purified carrier gas for a TOC analyzer from ambient air, wherein the method comprises:

[0036] Guiding the carrier gas consisting of ambient air from the inlet of the TOC analyzer through the following components to a storage container or a high-temperature furnace, wherein the treatment occurs within the TOC analyzer,

[0037] at least one filter,

[0038] at least one flow sensor,

[0039] a humidifier,

[0040] a pre-combustion chamber, in which the organic impurities in the air are oxidized to , and

[0041] an absorber, the absorber preferably includes soda lime, which adsorbs the generated in the pre-combustion chamber.

[0042] In one embodiment of the TOC analyzer or the method for producing a purified carrier gas according to the present invention, the filter has a pore size of 5 μm or less than 5 μm.

[0043] The present invention also relates to a method for determining the carbon content of a sample in a TOC analyzer according to the present invention or an embodiment thereof, comprising the following steps:

[0044] (i) Guide the carrier gas from the inlet of the TOC analyzer through the following components to the analysis unit,

[0045] at least one filter,

[0046] at least one flow sensor,

[0047] a humidifier, and

[0048] a pre-combustion chamber that oxidizes organic air impurities to ,

[0049] an absorber, the absorber preferably includes soda lime,

[0050] at least one pump, and

[0051] a high-temperature furnace (9);

[0052] (ii) Optionally stop the flow of the carrier gas through the high-temperature furnace;

[0053] (iii) Use an injection unit to inject a sample into the high-temperature furnace;

[0054] (iv) Evaporate and / or oxidize the sample at a temperature above 680 °C to form water vapor and carbon dioxide gas until the sample injected into the high-temperature furnace is evaporated;

[0055] (v) Start the flow of the carrier gas through the high-temperature furnace, thereby transporting the carbon dioxide gas generated during the evaporation and / or oxidation of the sample to the analysis unit (12); and

[0056] (vi) Determine the carbon content of the sample based on the carbon dioxide gas generated during the oxidation of the sample, with the introduced carrier gas consisting of ambient air.

[0057] In one embodiment of the method for generating a purified carrier gas or the method for determining the carbon content, during the evaporation of water and / or oxidation of the sample at a temperature above 680 °C to form water vapor and carbon dioxide gas, an oxidation catalyst is added, and the oxidation catalyst is selected from platinum (Pt) and palladium (Pd), and the platinum (Pt) and palladium (Pd) are applied as active components to a heat-resistant carrier material selected from or of.

[0058] In an embodiment where a sample with a volume of 1,000 μL or more is injected, the flow of the carrier gas is stopped during injection. In an embodiment where the injected volume is 100 - 200 μL, preferably 100 μL, the flow of the purified carrier gas is not stopped.

[0059] All embodiments of the above TOC analyzers and methods can be combined with each other in each case, provided that this is technically possible. Description of the Drawings

[0060] The following description explains the present invention in more detail with reference to the embodiments shown in the accompanying drawings.

[0061] In the figures:

[0062] Figure 1 : is the layout of a TOC analyzer according to the present invention. Detailed Description of the Invention

[0063] Figure 1 Shows the layout of an embodiment of a TOC analyzer (1) according to the present invention. Ambient air is guided through an inlet (2) of the TOC analyzer (1), through at least one filter (3), two flow sensors (4.1, 4.2) and a humidifier (5), to a pre-combustion chamber (6) and an absorber (7) - in the pre-combustion chamber (6) the organic impurities in the air are oxidized to , the absorber (7) preferably comprises soda lime for absorbing - thus obtaining a purified carrier gas. Then, the purified carrier gas is fed via a pump (8), preferably a diaphragm pump (8), to a high-temperature furnace (9).

[0064] When injecting a volume of more than 1,000 μL, the flow of the purified carrier gas is stopped, and the liquid sample to be analyzed is injected into the high-temperature furnace (9) via an injection unit (14). In the foregoing step, inorganic carbon compounds are removed from the liquid sample; wherein in this step, the purified carrier gas can also be used as a carrier gas.

[0065] The sample to be analyzed is evaporated under high-temperature conditions - for example at 680°C - 1200°C, preferably at a temperature above 68°C - and converted into . The carrier gas transports the carbon dioxide gas generated during sample evaporation and / or oxidation to an analysis unit (12). The analysis unit (12) including an NDIR sensor determines the carbon content of the sample based on the carbon dioxide gas generated during oxidation of the sample in the carrier gas stream with the purified carrier gas. The TOC analyzer (1) further includes a data processing unit (13), which is designed to control the flow rate of the carrier gas through at least one pump (8) or at least one flow sensor, control and / or regulate the injection unit (14), and determine the carbon content of the sample.

[0066] The carrier gas introduced into the TOC analyzer consists of ambient air. The flow sensors (4.1 - 4.2) control the flow rate of the carrier gas.

[0067] Reference numerals list

[0068] (1) TOC analyzer

[0069] (2) Inlet for carrier gas consisting of ambient air

[0070] (3) Filter

[0071] (4.1, 4.2) Flow sensor

[0072] (5) Humidifier

[0073] (6) High temperature pre-combustion chamber

[0074] (7) Absorber, soda lime

[0075] (8) Pumps, diaphragm pumps

[0076] (9) High temperature furnace

[0077] (10) Condensation unit

[0078] (11) Acid filter

[0079] (12) Analysis unit, NDIR sensor

[0080] (13) Data processing unit

[0081] (14) Injection unit

Claims

1. A TOC analyzer (1) for determining the carbon content of a sample, comprising: an inlet (2) for a carrier gas to enter the TOC analyzer, wherein the carrier gas is formed to be directed to a high temperature furnace (9) via - at least one filter (3); - at least one flow sensor (4), - a humidifier (5), and - a pre-combustion chamber (6), which is designed as a high-temperature combustion chamber to oxidize organic impurities in the air into , - The absorber (7) The absorber (7) preferably comprises soda lime, - at least one pump (8), in The high temperature furnace (9) is designed to evaporate or oxidize the sample at a high temperature to form water vapor and carbon dioxide gas; The carrier gas is formed to transport the carbon dioxide gas generated during oxidation of the sample in the high temperature furnace (9) to an analysis unit (12); The at least one flow sensor (4) and the at least one pump (8) are designed to adjust the flow rate of the carrier gas through the high temperature furnace (6); an injection unit (14), the injection unit (14) being configured to inject a liquid sample into the high-temperature furnace (9); an analysis unit (12) designed to measure the carbon content of the sample based on the carbon dioxide gas generated by the oxidation of the sample; and A data processing unit (13), wherein the data processing unit (13) is designed to perform the following steps: The carrier gas flow rate is controlled by The at least one pump (8), the at least one flow sensor, controlling and / or regulating the injection unit (14), and The carbon content of the sample is determined.

2. The TOC analyzer according to claim 1, wherein: The introduced carrier gas consists of ambient air.

3. The TOC analyzer according to claim 1 or 2, wherein: A condensation unit (10) and an acid filter (11) are arranged between the high-temperature furnace (9) and the analysis unit (12).

4. The TOC analyzer according to any one of claims 1 to 3, wherein The at least one pump (8) comprises at least one diaphragm pump (8).

5. The TOC analyzer according to any one of claims 1 to 4, wherein: The at least one diaphragm pump (8) is designed to achieve a pressure of 400 mbar.

6. The TOC analyzer according to any one of claims 1 to 5, wherein: The analysis unit (12) comprises a non-dispersive infrared (NDIR) sensor.

7. The TOC analyzer according to any one of claims 1 to 6, wherein: A flow sensor (10) is connected downstream of the filter (3) and the analysis unit (12).

8. A method for producing purified carrier gas for a TOC analyzer from ambient air wherein: The method comprises: A carrier gas consisting of ambient air is directed from the inlet (2) of the TOC analyzer (1) to a storage container or a high temperature furnace (9) via: at least one filter (3), at least one flow sensor (4), Humidifier (5), A pre-combustion chamber (6) in which organic impurities in the air are oxidized at a temperature above 680°C to ,as well as The absorber (7) The absorber (7) preferably comprises soda lime which absorbs the , Among other things, processing occurs within the TOC analyzer.

9. The TOC analyzer according to any one of claims 1 to 7 or the method according to claim 8, wherein: The filter (3) has a pore size of 5 μm or less.

10. Purified compressed air for a TOC analyzer, the purified compressed air being obtainable by the method according to claim 8 or 9 followed by compressing the air.

11. A method for determining the carbon content of a sample in a TOC analyzer (1) according to any one of claims 1 to 7, comprising the following steps: (i) directing a carrier gas from the inlet (2) of the TOC analyzer (1) to the analysis unit (12) by: at least one filter (3), at least one flow sensor (4), a humidifier (5), and A pre-combustion chamber (6) is provided, wherein the pre-combustion chamber (6) oxidizes the organic air impurities into ,as well as The absorber (7) The absorber (7) preferably comprises soda lime, at least one pump (8), and High temperature furnace (9); (ii) optionally stopping the flow of the carrier gas through the high temperature furnace (9); (iii) injecting the sample into the high temperature furnace (9) using the injection unit (14); (iv) evaporating and / or oxidizing the sample at a temperature above 680° C. to form water vapor and carbon dioxide gas until the sample injected into the high temperature furnace (6) is evaporated; (v) starting the flow of the carrier gas through the high temperature furnace (9) to deliver the carbon dioxide gas generated during evaporation and / or oxidation of the sample to an analysis unit (12); as well as (vi) determining the carbon content of the sample by means of the analysis unit (12) based on the carbon dioxide gas generated during the oxidation of the sample, wherein the carrier gas introduced consists of ambient air.

12. The method for producing a purified carrier gas according to claim 8 or 9 or the method for determining the carbon content of a sample in a TOC analyzer according to claim 11, wherein: During evaporation of water and / or oxidation of the sample to form water vapor and carbon dioxide gas at a temperature above 680°C, an oxidation catalyst is added, the oxidation catalyst being selected from platinum (Pt) and palladium (Pd), the platinum (Pt) and palladium (Pd) being applied as active components to a sample selected from or Heat resistant carrier material.

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