Gas measuring apparatus and method for measuring cyanide in the presence of hydrogen cyanide.

Abstract

A gas measuring device (100) for measuring cyanide in the presence of hydrogen cyanide. The gas measuring device (100) includes a measuring chamber (101), heating elements (103, 203), and electrochemical sensors (105, 200); wherein the measuring chamber (101) is configured to contain a sample; wherein the heating element (103) is configured to thermally decompose the cyanide contained in the sample into decomposition products; and wherein the sensors (105, 200) are configured to detect the decomposition products of cyanide obtained by thermal decomposition. Furthermore, the described invention relates to a method for measuring cyanide in the presence of hydrogen cyanide.

Description

Technical Field

[0001] This invention relates to a gas measuring device and method for measuring cyanide in the presence of hydrogen cyanide. Background Technology

[0002] In agriculture, fumigation (i.e., disinfection by smoking) is a common method for eliminating germs and bacteria on products that are later used and exported in the food industry.

[0003] In the past, methyl bromide was commonly used for fumigation. However, due to its strong carcinogenic effects, its use has been banned in some countries. Cyanide has been proven effective as an alternative.

[0004] Since cyanide often appears in the gas supply along with hydrogen cyanide (HCN), it is necessary to measure cyanide in the presence of hydrogen cyanide.

[0005] Semiconductor sensors are typically used to measure cyanide; however, these sensors exhibit limited sensitivity and stability, and consequently, they are unsuitable or only conditionally suitable for detecting occupational exposure limits exceeding 5 ppm.

[0006] In addition, cyanide can be measured using a mass spectrometer. However, because mass spectrometers are not lightweight and are complex to use, they are also unsuitable or only conditionally suitable for detecting occupational exposure limits exceeding 5 ppm.

[0007] JP 2008 076 235 A describes a method for measuring cyanide, in which hydrogen sulfide is vaporized from a sample so that the sample can be measured by means of a hydrogen cyanide gas sensor. Summary of the Invention

[0008] Based on the prior art described above, the objective of this invention is to provide a method for measuring cyanide that at least partially avoids these drawbacks. Therefore, the objective of this invention is to provide a method for reliably and simply identifying exposures exceeding permissible occupational exposure limits for cyanide.

[0009] The foregoing task is addressed by the subject matter of the respective independent claims. Further features and details of the invention are derived from the dependent claims, the specification, and the drawings. Here, the features and details described in connection with the gas measuring device also apply to the features and details described in connection with the method according to the invention, and in all cases the reverse, so that reference is always made to the disclosures regarding various aspects of the invention, or that reference is always possible to the disclosures regarding various aspects of the invention.

[0010] According to the first aspect, to address this task, a gas measuring device for measuring cyanide in the presence of hydrogen cyanide is introduced. The gas measuring device includes a measuring chamber, a heating element, and an electrochemical sensor. The measuring chamber is configured to contain a sample. The heating element is configured to thermally decompose the cyanide contained in the sample into decomposition products. The sensor is configured to detect the decomposition products of cyanide obtained through thermal decomposition.

[0011] The gas measuring device according to the invention is configured to reliably or selectively determine the concentration of cyanide in a sample with high sensitivity, particularly the sensitivity that allows reliable verification of cyanide from a concentration of 1 ppm, even in the presence of hydrogen cyanide.

[0012] To measure the concentration of cyanide in a sample, the described gas measuring device includes an electrochemical master sensor, which is used in combination with a heating element, such as a heating wire or a heating plate.

[0013] Since electrochemical sensors cannot directly detect or measure cyanide, the present invention employs a heating element to thermally decompose the corresponding cyanide molecules in the sample. Specifically, the heating element performs the pyrolysis of the cyanide molecules. The thermal decomposition forms decomposition products, such as nitrogen oxides or hydrogen cyanide, which can be detected by the electrochemical main sensor configured according to the present invention.

[0014] The temperature can be selected based on the reaction conditions present in the chamber of the described gas measuring device, and this temperature is set by means of a heating element to thermally decompose the corresponding cyanide molecules. In particular, the temperature can be set based on the corresponding catalyst present in the chamber. Alternatively or additionally, it is conceivable to set the temperature based on other reaction conditions, such as, for example, the relative humidity present in the chamber.

[0015] The heating element provided according to the invention can be freely arranged within the chamber of the described gas measuring device. This means that the heating element and the sensor can be arranged separately from each other. Alternatively, the heating element and the sensor may be arranged in a combined or integrated manner in a single or combined component.

[0016] Furthermore, the heating element can be configured to at least partially decompose cyanide contained in the sample into nitrogen oxides, while the sensor is configured to detect nitrogen oxides.

[0017] Since nitrogen oxides (such as nitric oxide or nitrogen dioxide) can be detected simply and accurately using electrochemical sensors, setting the heating element to a temperature range for the decomposition of cyanide into nitrogen oxides (that is, into nitric oxide and / or nitrogen dioxide) is particularly advantageous for the operation of the gas measuring device described.

[0018] Furthermore, the gas measuring device may include a calculation unit configured to calculate the concentration of hydrogen cyanide contained in the sample based on measurements determined by a sensor. Alternatively, the gas measuring device may include a calculation unit, and the sensor may be configured to detect hydrogen cyanide, wherein the calculation unit is configured to calculate the concentration of hydrogen cyanide contained in the sample based on measurements determined by the sensor during a first time period prior to thermal decomposition by the heating element, and to calculate the concentration of cyanide contained in the sample based on measurements determined by the sensor during a second time period after thermal decomposition by the heating element.

[0019] Using a computing unit, such as a computer or any other form of programmable circuit, the concentration of cyanide in a given sample can be deduced by using pre-given coefficients from measurements determined, for example, by a sensor in the described gas measuring device. To determine or update the coefficients, the sensor can be calibrated, for example, based on a calibration sample.

[0020] The sensor provided according to the invention may be sensitive to hydrogen cyanide, wherein, in order to avoid interaction between hydrogen cyanide already present in the corresponding sample and hydrogen cyanide produced by the thermal decomposition process, the concentration of hydrogen cyanide already present in the sample is determined before the thermal decomposition process. Correspondingly, based on the difference between the measurements determined before and after the thermal decomposition process, the concentration of cyanide that has been decomposed into hydrogen cyanide can be inferred, and the concentration of hydrogen cyanide initially present in the sample can be inferred.

[0021] Furthermore, the gas measuring device may be configured to have a surface that acts as a catalyst in the thermal decomposition of cyanide.

[0022] By using a catalyst or catalytic surface, the temperature required for the thermal cracking process of cyanide molecules by the heating element provided according to the present invention can be reduced. Furthermore, by appropriately selecting the material of the corresponding surface and, in conjunction with appropriately selecting the temperature set by the heating element, the corresponding cracking products generated by the cracking process can be influenced, such as the formation of nitrogen oxides or hydrogen cyanide through the cracking process.

[0023] In addition, the surface may be configured to include at least one material from the following list: platinum, palladium, ruthenium, rhodium, iridium, and osmium.

[0024] Depending on the selection of one or more materials used for the surface provided according to the invention, thermal energy is required more or less for pyrolysis. Correspondingly, depending on the selection of materials or combinations of materials, a suitable heating element can be selected, preferably having minimal energy consumption.

[0025] The material or combination of materials of the surface provided according to the present invention can be provided directly or in a supported manner on alumina, zirconium oxide, silicon oxide, cerium oxide or ceramic.

[0026] Alternatively, the sensor and heating element can be configured to be combined into an integrated assembly, and the heating element can be configured to heat the surface of the assembly.

[0027] Compact and energy-efficient measurement units can be provided using integrated components, such as catalytic combustion devices with pulistor beads. The outer surface of the pulistor beads can be made of a catalytic material that reduces the energy required for the pyrolysis process.

[0028] Furthermore, the heating element, or a combination of the heating element and the surface, can be configured to decompose cyanide contained in the sample into nitrogen oxides or into hydrogen cyanide.

[0029] By combining the heating element and the catalytic surface, the pyrolysis products generated during the thermal cracking process can be precisely predetermined. In particular, the energy input provided by the catalytic surface or the heating element can be quantified such that nitrogen oxides or hydrogen cyanide are formed.

[0030] In addition, the measuring chamber can be configured to include filtration units that are permeable to cyanide and impermeable to hydrogen cyanide.

[0031] To minimize the influence of hydrogen cyanide on the detection of cyanide, the described gas measuring device may include a filter that prevents hydrogen cyanide from entering the chamber of the gas measuring device. Alternatively, the filter unit may be a membrane, such as a PTFE membrane, which is permeable to both hydrogen cyanide and cyanide, and is configured to minimize the flow influence on detection performed using a sensor provided according to the invention.

[0032] Additionally, the gas measuring device may be configured to include a pump for introducing a sample into the measuring chamber.

[0033] The gas measuring device described can be a passive gas measuring device based on the diffusion principle, or it can include a pump that can actively extract a sample from the environment and introduce the sample into the chamber of the gas measuring device.

[0034] Additionally, the gas measuring device may be configured to include an auxiliary sensor, wherein the sensor is configured to detect nitrogen oxides, and the auxiliary sensor is configured to detect hydrogen cyanide.

[0035] By using two sensors—one for detecting nitrogen oxides and one for detecting hydrogen cyanide—the concentrations of the two gases, namely cyanide and hydrogen cyanide, can be determined.

[0036] In a second aspect, the invention relates to a method for measuring cyanide in the presence of hydrogen cyanide, wherein the method comprises: a providing step for providing a possible construction scheme of the gas measuring device described herein; a conveying step for conveying a sample into the measuring chamber of the gas measuring device; a pyrolysis step for thermally pyrolyzing the cyanide in the sample by means of a heating element of the gas measuring device; and a detection step for detecting the pyrolysis products of the cyanide produced by the pyrolysis step by means of a sensor of the gas measuring device.

[0037] In particular, the method described is used to operate the gas measuring device described.

[0038] Optionally, the method may further include a detection step for detecting hydrogen cyanide. In addition to detecting pyrolysis products, hydrogen cyanide detection can also be used to determine information about the concentration of hydrogen cyanide in the sample, in addition to information about the cyanide concentration. Alternatively, detection of hydrogen cyanide can be performed to detect the pyrolysis products themselves.

[0039] Furthermore, it can be configured to perform hydrogen cyanide detection using a sensor in a first detection step prior to pyrolysis, and in a second detection step after pyrolysis. Attached Figure Description

[0040] Further improvements to the invention will derive from the following description of several embodiments of the invention, illustrated in the figures. All features and / or advantages (including construction details and spatial arrangements) derived from the claims, specification, or drawings may individually or in various combinations reflect the inventive essence. Schematably, respectively:

[0041] Figure 1 A schematic diagram of a possible construction scheme for a gas measuring device according to the present invention is shown.

[0042] Figure 2 A schematic diagram illustrating a possible construction scheme for a sensor according to the present invention is shown.

[0043] Figure 3 A schematic diagram of the process of the method according to the present invention is shown. Detailed Implementation

[0044] exist Figure 1 The image shows a gas measuring device 100. The gas measuring device 100 includes a measuring chamber 101, a heating element 103, and an electrochemical sensor 105.

[0045] To measure the concentration of cyanide in the presence of hydrogen cyanide, the sample in the measuring chamber 101 is heated by a heating element 103, thereby causing the sample to undergo thermal decomposition. The decomposition products formed through thermal decomposition are detected by a sensor 105. Based on the measurement determined by the sensor 105, the concentration of cyanide in the sample can be deduced, for example, using an optional computing unit 107.

[0046] Alternatively, the measurement value determined by sensor 105 can be directly used to represent the concentration of cyanide in the sample. For this purpose, sensor 105 can be connected to output unit 109, such as a display and / or speaker.

[0047] The calculation unit 107 can be configured to output a warning via the output unit 109 if the concentration of cyanide or hydrogen cyanide detected in the corresponding sample is above a predetermined threshold.

[0048] In this invention, the gas measuring device 100 is a mobile or portable gas measuring device with a power supply, which allows the gas measuring device to be used "on the spot".

[0049] In order to minimize the energy requirement for cyanide molecules in the thermal pyrolysis sample, or to check or control the pyrolysis process of selected pyrolysis products, such as nitrogen oxides or hydrogen cyanide, a catalytic surface 111 may be arranged in the chamber 101, especially on the heating element 103.

[0050] exist Figure 2 The sensor 200 is shown in the figure. The sensor 200 is an integrated component and includes a measuring electrode 201, a heating element 203, and a catalytic surface 205 in the form of a catalytic bead, which surrounds the heating element 203 or is constructed as an integral part of the heating element 203. Correspondingly, the heat energy generated by the heating element 203 is transferred to the catalytic surface 205.

[0051] Once cyanide molecules come into contact with the catalytic surface 205, they are thermally decomposed into, for example, nitrogen dioxide and carbon dioxide due to the heat energy introduced into the catalytic surface 205 and the catalytic properties of the catalytic surface 205.

[0052] Sensor 200 is specifically configured to detect nitrogen dioxide and, correspondingly, determine a measurement value based on the measured nitrogen dioxide concentration. Correspondingly, the determined measurement value is proportional to the cyanide concentration and enables an assessment of whether the cyanide concentration in the environment is above or below a predetermined threshold.

[0053] exist Figure 3The diagram illustrates method 300. Method 300 includes: a providing step 301 for providing a possible construction scheme of the described gas measuring device; a delivery step 303 for delivering a sample into the measuring chamber of the gas measuring device; a pyrolysis step for thermally pyrolyzing cyanide in the sample using a heating element of the gas measuring device; and a detection step 305 for detecting pyrolysis products of cyanide generated by the pyrolysis step using a sensor of the gas measuring device.

[0054] List of reference numerals

[0055] 100 Gas Measuring Equipment

[0056] Measurement Room 101

[0057] 103 Heating element

[0058] 105 Sensors

[0059] 107 computing units

[0060] 109 Output Unit

[0061] 111 Catalytic Surface

[0062] 200 sensors

[0063] 201 Measuring Electrode

[0064] 203 Heating element

[0065] 205 Catalytic Surface

[0066] 300 methods

[0067] 301 provides steps

[0068] 303 Conveying Steps

[0069] 305 Detection steps.

Claims

1. A gas measuring device (100) for measuring cyanide in the presence of hydrogen cyanide. The gas measuring device (100) mentioned above includes: - Measurement Room (101) - Heating elements (103, 203). - Electrochemical sensor (105, 200). The measuring chamber (101) is configured to accommodate a sample. The heating element (103) is configured to thermally decompose the cyanide contained in the sample into pyrolysis products. The electrochemical sensor (105, 200) is configured to detect the pyrolysis products of the cyanide obtained through the thermal pyrolysis. The gas measuring device (100) has surfaces (111, 205) that act as catalysts in the thermal decomposition of cyanide, and the surfaces (111, 205) comprise at least one material from the following list: Platinum, palladium, ruthenium, rhodium, iridium, osmium The measuring chamber (101) includes a filtration unit that is permeable to cyanide and impermeable to hydrogen cyanide.

2. The gas measuring device (100) according to claim 1. Its features are, The heating elements (103, 203) are configured to at least partially decompose cyanide contained in the sample into nitrogen oxides, and The sensors (105, 200) are configured to detect nitrogen oxides.

3. The gas measuring device (100) according to claim 1 or 2. Its features are, The gas measuring device (100) includes a calculation unit (107) configured to calculate the concentration of hydrogen cyanide contained in the sample based on the measurement values ​​determined by the sensors (105, 200), or The gas measuring device (100) includes a computing unit (107), and the sensors (105, 200) are configured to detect hydrogen cyanide, wherein the computing unit (107) is configured to calculate the concentration of hydrogen cyanide contained in the sample based on measurements determined by the sensors (105, 200) during a first time period prior to thermal decomposition by the heating elements (103, 203), and to calculate the concentration of cyanide contained in the sample based on measurements determined by the sensors (105, 200) during a second time period after thermal decomposition by the heating elements (103, 203).

4. The gas measuring device (100) according to claim 1 or 2. Its features are, The sensors (105, 200) and the heating elements (103, 203) are combined into an integrated assembly, and the heating elements (103, 203) are configured to heat the surface of the assembly.

5. The gas measuring device (100) according to claim 1 or 2. Its features are, The heating element (103, 203) or a combination of the heating element (103, 203) and the surface (111, 205) is configured to decompose cyanide contained in the sample into nitrogen oxides or into hydrogen cyanide.

6. The gas measuring device (100) according to claim 1 or 2. Its features are, The gas measuring device (100) includes a pump for introducing a sample into the measuring chamber (101).

7. The gas measuring device (100) according to claim 1 or 2. Its features are, The sensor (200) or the heating element (103, 203) includes a catalytic bead.

8. The gas measuring device (100) according to claim 1 or 2. Its features are, The gas measuring device (100) includes an auxiliary sensor, wherein the sensor (105, 200) is configured to detect nitrogen oxides, and the auxiliary sensor is configured to detect hydrogen cyanide.

9. A method (300) for measuring cyanide in the presence of hydrogen cyanide, wherein, The method includes: - Provide (301) the gas measuring device (100) according to any one of claims 1 to 8. - The sample is transported to the measuring chamber (101) of the gas measuring device (100) (303). - The cyanide in the sample is thermally decomposed using the heating elements (103, 203) of the gas measuring device (100). - Using the sensors (105, 200) of the gas measuring device (100), the cracking products of the cyanide produced by the thermal cracking are detected (305).

10. The method (300) according to claim 9. Its features are, The method (300) further includes: - Detects hydrogen cyanide.

11. The method (300) according to claim 10. Its features are, In a first detection step prior to the pyrolysis, hydrogen cyanide is detected using the sensors (105, 200), and in a second detection step following the pyrolysis, hydrogen cyanide is detected using the sensors (105, 200).

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