CN114137055A - Electrochemical gas detection device and gas detection method - Google Patents

Electrochemical gas detection device and gas detection method Download PDF

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Publication number
CN114137055A
CN114137055A CN202111641235.5A CN202111641235A CN114137055A CN 114137055 A CN114137055 A CN 114137055A CN 202111641235 A CN202111641235 A CN 202111641235A CN 114137055 A CN114137055 A CN 114137055A
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gas
sensor
electrochemical
gas detection
concentration
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郭安波
李亮
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Suzhou Promisense Electronic Technology Co ltd
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Suzhou Promisense Electronic Technology Co ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G01N27/4162—Systems investigating the composition of gases, by the influence exerted on ionic conductivity in a liquid
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/10—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using catalysis

Abstract

The invention discloses an electrochemical gas detection device and a detection method, which are used for detecting nitrous oxide (N) in the atmosphere2O) content comprising a catalytic device, a cooling device, a calculation unit, a first CO (carbon monoxide) sensor electrically connected to the calculation unit and a second CO (carbon monoxide) sensor electrically connected to the calculation unit. By adopting the combined use of the electrochemical CO sensor and the catalytic device, compared with the prior optical detection method, infrared method and the like, the method realizes the low-cost detection of the ppb level N in the atmosphere2O gas concentration, the electrochemical gas detection device is suitable for most environment-friendly detection of N in greenhouse gas2And the method has wide application prospect in the case of O concentration.

Description

Electrochemical gas detection device and gas detection method
Technical Field
The invention relates to the field of gas detection, in particular to an electrochemical gas detection device and a gas detection method.
Background
Global warming is the most significant environmental problem facing humans to date, the main cause of which is the emission of greenhouse gases produced by human activities. Greenhouse gases mainly include water vapor (H)2O), carbon dioxide (CO)2) Ozone (O)3) Methane (CH)4) Nitrous oxide (N)2O), Perfluorocarbons (PFCs), Hydrofluorocarbons (HFCs), chlorofluorocarbons (HCFCs), and sulfur hexafluoride (SF)6) And the like.
Detecting trace amounts of N in the atmosphere2The method mainly adopted by the greenhouse gas O comprises the following steps: quantum Cascade Laser Analysis Systems (QCLAS), Cavity ring-down absorption spectroscopy (CRLAS), Gas Filter coherent Infrared spectroscopy (GFC), and Non-Dispersive Infrared (NDIR). But the equipment used by the former two is very expensive; GFC stability was good, but ppb level N could not be detected2O, the technical problem of gas leakage of a coherent filtering gas chamber, and CO2The problem of cross-interference; NDIR is inexpensive and simple in structure, but cannot detect N at ppb level2O, low resolution, large temperature drift, and poor long-term stability.
At present, the direct measurement of N by an electrochemical gas sensor does not exist in the market2Method of O due to N2O is chemically stable and is not easily oxidized or reduced at normal temperature. Manufacturers of large electrochemical sensors have no electrochemical principle of N2O-sensors, which customers are forced to have, can only measure ppb levels of N using expensive optical instruments2The O concentration.
Therefore, it is necessary to provide a new N2An O gas detection device and a gas detection method are provided to solve the above problems.
Disclosure of Invention
In view of the above disadvantages of the prior art, the present invention provides a method for detecting N in the atmosphere2The gas detection device for O content adopts cheap pure electrochemical and chemical catalytic methods to detect the N in the atmosphere at ppb level instead of expensive optical methods2The concentration of O gas.
In order to achieve the purpose, the invention adopts the following technical scheme: an electrochemical gas detection device for detecting nitrous oxide (N) in atmosphere2O) content comprising a catalytic device, a cooling device, a calculation unit, a first CO (carbon monoxide) sensor electrically connected to the calculation unit and a second CO (carbon monoxide) sensor electrically connected to the calculation unit.
As a further improvement of the invention, the air outlet of the first CO sensor is connected with the air inlet of the catalytic device, the air outlet of the catalytic device is connected with the air inlet of the cooling device, and the air outlet of the cooling device is connected with the air inlet of the second CO sensor.
As a further development of the invention, the first CO sensor and the second CO sensor are both electrochemical CO sensors.
As a further development of the invention, the first CO sensor and the second CO sensor each have a resolution in ppb level.
As a further improvement of the present invention, the first CO sensor and the second CO sensor each include an electrode, a filter, a gas permeable membrane, an electrolyte, an electrode lead-out wire, and a case.
As a further development of the invention, the electrodes comprise a working electrode, a counter electrode and a reference electrode.
In order to achieve the purpose, the invention also adopts the following technical scheme: a gas detection method comprises the electrochemical gas detection device and further comprises the following steps:
s1: the measured gas enters a first CO sensor, the first CO sensor detects the CO concentration C1 in the measured gas and transmits C1 to the calculation unit;
s2: the measured gas enters the catalytic device from the first CO sensor, and N in the measured gas is generated under the action of the catalyst and high temperature2Reaction of O and CO to N2And CO2；
S3: the reacted gas to be detected enters a cooling device from a catalytic device, and the gas to be detected is cooled to room temperature;
s4: the cooled measured gas enters a second CO sensor from the cooling device, and the second CO sensor detects the CO concentration C2 in the measured gas at the moment and transmits C2 to the calculating unit;
s5: the measured gas is discharged to the atmosphere, and the calculating unit calculates the target value, namely N in the measured gas according to the known C1 and C22Concentration C of ON2O。
As a further improvement of the present invention, in step S2, the catalyst is a particulate metal or metal oxide catalyst.
As a further improvement of the invention, the catalyst is molecular sieve particles loaded with iron ions, copper clusters and alpha-MnO2One or more of the nanorods.
As a further improvement of the invention, in step S5, N in the measured gas2Concentration C of ON2O＝C1-C2。
Compared with the prior art, the electrochemical gas detection device and the gas detection method have the beneficial effects that:
(1) expensive optical methods are completely abandoned, and cheap pure electrochemical and chemical catalytic methods are adopted to detect N in the atmosphere at ppb level2The concentration of O gas greatly reduces the cost compared with the prior art;
(2) the electrochemical CO sensor has the biggest characteristics that the current is completely in direct proportion to the CO concentration, and the output signal and the gas concentration are in a good linear relation, so that the signal processing and display are very convenient;
(3) the atmosphere contains CO at a concentration of 300-400 ppb and the atmosphere contains N2The concentration of O is lower than that of CO, so the atmospheric environment is reduced to N2O provides a reducing agent.
Drawings
Fig. 1 is a schematic structural diagram and a schematic flow diagram of a detected gas of an electrochemical gas detection device according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. If several embodiments exist, the features of these embodiments may be combined with each other without conflict. When the description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The statements made in the following exemplary detailed description do not represent all implementations consistent with the present disclosure; rather, they are merely examples of apparatus, products, and/or methods consistent with certain aspects of the invention, as set forth in the claims below.
The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. As used in the specification and claims of this invention, the singular form of "a", "an", or "the" is intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be understood that the use of terms such as "first," "second," and the like, in the description and in the claims of the present invention do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. Unless otherwise indicated, the terms "front," "back," "up," "down," and the like in the description of the invention are used for convenience of description and are not limited to a particular position or spatial orientation. The word "comprise" or "comprises", and the like, is an open-ended expression meaning that an element that precedes "includes" or "comprising" includes "that the element that follows" includes "or" comprises "and its equivalents, that do not preclude the element that precedes" includes "or" comprising "from also including other elements. If the invention is referred to as "a plurality", it means two or more.
Referring to fig. 1, the present invention discloses an electrochemical gas detecting device for detecting nitrous oxide (N) in the atmosphere2O) content comprising a catalytic device, a cooling device, a calculation unit, a first CO (carbon monoxide) sensor electrically connected to the calculation unit and a second CO (carbon monoxide) sensor electrically connected to the calculation unit. The gas outlet of the first CO sensor is connected with the gas inlet of the catalytic device through a pipeline, the gas outlet of the catalytic device is connected with the gas inlet of the cooling device through a pipeline, and the gas outlet of the cooling device is connected with the gas inlet of the second CO sensor through a pipeline. The computing unit mainly processes various information data, and the computing unit in the invention is a common computing unit in the technical field of numerical control, and is not described in detail in the invention.
Further, the first CO sensor and the second CO sensor are both electrochemical CO sensors and both have a resolution on the ppb level. The first CO sensor and the second CO sensor respectively comprise an electrode, a filter, a breathable film, electrolyte, an electrode outgoing line and a shell. Wherein the electrodes include a working electrode, a counter electrode, and a reference electrode.
The cooling device in this embodiment adopts a section of stainless steel tube, and the gas to be measured passes through the stainless steel tube, and uses the fan to cool the stainless steel tube and then indirectly cool the gas to be measured. Alternatively, in some embodiments of the present invention, other conventional gas cooling devices, such as a condenser tube, etc., may be used.
The first CO sensor and the second CO sensor in the electrochemical gas detection device are respectively electrically connected with the computing unit, the collected electric signals are output to the computing unit, the computing unit converts the received electric signals into data information, the data information is calculated according to a set computing program, and finally a detection result is output.
The invention also provides a gas detection method based on the electrochemical gas detection device, which comprises the following steps:
s1: the measured gas enters a first CO sensor, the first CO sensor detects the CO concentration C1 in the measured gas and transmits C1 to the calculation unit;
s2: the measured gas enters the catalytic device from the first CO sensor, and N in the measured gas is generated under the action of the catalyst and high temperature2Reaction of O and CO to N2And CO2；
S3: the reacted gas to be detected enters a cooling device from a catalytic device, and the gas to be detected is cooled to room temperature;
s4: the cooled measured gas enters a second CO sensor from the cooling device, and the second CO sensor detects the CO concentration C2 in the measured gas at the moment and transmits C2 to the calculating unit;
s5: the measured gas is discharged to the atmosphere, and the calculating unit calculates the target value, namely N in the measured gas according to the known C1 and C22Concentration C of ON2O。
The gas to be detected is atmospheric air, and the electrochemical gas detection device is mainly used for detecting N in the atmosphere2And (4) the content of O.
In addition to the above examples, the catalyst used in step S2 was a metal or metal oxide catalyst in the form of particles, and further, the catalyst used in step S2 was molecular sieve particles loaded with iron ions, copper clusters, α -MnO2One or more of the nanorods.
It will be appreciated by those skilled in the art that the principle of operation of a chemical sensor is: the conducting system of the chemical sensor receives the response signal of the recognition system, and transmits the response signal to the electronic system for amplification or conversion output in the form of voltage, current or light intensity through the electrode, the optical fiber or the mass sensitive element, and finally the response signal of the recognition system is converted into a signal which can be used as an analysis by people, and the quantity of the object to be detected in the sample is detected.
As will be understood by those skilled in the art, the electrochemical CO sensor is designed in a closed structure, and is usually used in combination with an alarm, and takes potentiostatic electrolysis as a basic principle, and has a chemical reaction formula:
a working electrode: CO 22+H2O→CO2+2H++2e-
Counter electrode: 1/2O2+2H++2e-→H2O
And (3) total reaction: 2CO + O2→2CO2
This redox reversible reaction occurs all the time between the working electrode and the counter electrode and creates a potential difference between the electrodes. But also limits the range in which the carbon monoxide gas concentration can be detected, since the reactions occurring at both electrodes polarize the electrodes, which makes it difficult to maintain the interpolar potential constant. In order to maintain the interelectrode potential constant, a reference electrode is introduced, in the three-electrode electrochemical gas sensor, the output end of the three-electrode electrochemical gas sensor reflects the potential change between the reference electrode and the working electrode, and the reference electrode does not participate in oxidation or reduction reaction, so that the interelectrode potential can be maintained constant (namely constant potential), and the potential change is directly related to the change of the carbon oxide concentration. When the gas sensor generates an output current, its magnitude is proportional to the concentration of the gas. The concentration of carbon monoxide can be detected by measuring the output current of the sensor through the electrode lead wires by an external circuit, and the linear measurement range is wide.
In step S2, the catalytic device in this embodiment adopts a high-temperature quartz tube, and the quartz tube is filled with a granular chemical catalyst, but of course, other high-temperature resistant tubes and other catalysts with different shapes may also be adopted, and the granular catalyst increases the contact area between the detected gas and the catalyst, so that the reaction is more complete.
To make CO and N in the atmosphere2Reaction of O to CO2And N2While avoiding CO and O2Reaction takes place, the atmosphere contains a large amount of O2Further, the reaction amount of CO is interfered. Therefore, it is necessary to use a special catalyst for promoting CO and N2O reacts and blocks CO and O2The reaction takes place. CO and O2Reaction to CO2The condition is combustion, and a large number of experiments show that the adoption of the metal or metal oxide catalyst under the high-temperature condition can promote CO and N2Reaction of O, and prevention of CO and O2Further, molecular sieve particles having iron ions supported therein, copper clusters and α -MnO2The effect of the nano-rod catalyst is best.
The first CO sensor detects the original CO concentration C1 in the atmosphere, and the second CO sensor detects CO and N2The CO concentration remaining after the O reaction was C2. Since one CO molecule will reduce one N2O minutes, so the decrease in CO concentration is N in the atmosphere2Concentration of O, i.e. CN2O＝C1-C2。
The essence of the invention lies in that the combination of an electrochemical CO sensor and a catalytic device is adopted to form a new N2An O detection device realizes low-cost detection of N at ppb level in the atmosphere2O gas concentration, using special catalyst to make original CO and N in atmosphere2O reaction, and others are avoidedInterference of reaction, remaining with N in the detection process2CO from O reaction, indirectly measuring N in the original atmosphere2The O concentration.
In summary, compared with the prior art, the electrochemical gas detection device and the gas detection method of the present invention have the following advantages:
(1) expensive optical methods are completely abandoned, and cheap pure electrochemical and chemical catalytic methods are adopted to detect N in the atmosphere at ppb level2The concentration of O gas greatly reduces the cost compared with the prior art;
(2) the electrochemical CO sensor has the biggest characteristics that the current is completely in direct proportion to the CO concentration, and the output signal and the gas concentration are in a good linear relation, so that the signal processing and display are very convenient;
(3) the atmosphere contains CO at a concentration of 300-400 ppb and the atmosphere contains N2The concentration of O is lower than that of CO, so the atmospheric environment is reduced to N2O provides a reducing agent.
The above embodiments are only for illustrating the invention and not for limiting the technical solutions described in the invention, and the understanding of the present specification should be based on the technical personnel in the technical field, and although the present specification has described the invention in detail by referring to the above embodiments, the technical personnel in the technical field should understand that the technical personnel in the technical field can still make modifications or equivalent substitutions to the present invention, and all the technical solutions and modifications thereof without departing from the spirit and scope of the present invention should be covered in the claims of the present invention.

Claims (10)

1. An electrochemical gas detection device for detecting nitrous oxide (N) in atmosphere2O), characterized in that: the device comprises a catalytic device, a cooling device, a calculation unit, a first CO (carbon monoxide) sensor and a second CO (carbon monoxide) sensor, wherein the first CO (carbon monoxide) sensor is electrically connected with the calculation unit, and the second CO (carbon monoxide) sensor is electrically connected with the calculation unit.
2. The electrochemical gas detection device according to claim 1, wherein: the gas outlet of the first CO sensor is connected with the gas inlet of the catalytic device, the gas outlet of the catalytic device is connected with the gas inlet of the cooling device, and the gas outlet of the cooling device is connected with the gas inlet of the second CO sensor.
3. The electrochemical gas detection device according to claim 1, wherein: the first CO sensor and the second CO sensor are both electrochemical CO sensors.
4. The electrochemical gas detection device according to claim 3, wherein: the first CO sensor and the second CO sensor each have a resolution on the ppb level.
5. The electrochemical gas detection device according to claim 3, wherein: the first CO sensor and the second CO sensor respectively comprise an electrode, a filter, a gas-permeable membrane, electrolyte, an electrode lead-out wire and a shell.
6. The electrochemical gas detection device according to claim 5, wherein: the electrodes include a working electrode, a counter electrode, and a reference electrode.
7. A gas detection method comprising the electrochemical gas detection device according to claim 1, further comprising the steps of:
s1: the measured gas enters a first CO sensor, the first CO sensor detects the CO concentration C1 in the measured gas and transmits C1 to the calculation unit;
s2: the measured gas enters the catalytic device from the first CO sensor, and N in the measured gas is generated under the action of the catalyst and high temperature2Reaction of O and CO to N2And CO2；
S3: the reacted gas to be detected enters a cooling device from a catalytic device, and the gas to be detected is cooled to room temperature;
s4: the cooled measured gas enters a second CO sensor from the cooling device, and the second CO sensor detects the CO concentration C2 in the measured gas at the moment and transmits C2 to the calculating unit;
s5: the measured gas is discharged to the atmosphere, and the calculating unit calculates the target value, namely N in the measured gas according to the known C1 and C22Concentration C of ON2O。
8. The gas detection method according to claim 7, characterized in that: in step S2, the catalyst is a particulate metal or metal oxide catalyst.
9. The gas detection method according to claim 8, characterized in that: the catalyst is molecular sieve particles loaded with iron ions, copper clusters and alpha-MnO2One or more of the nanorods.
10. The gas detection method according to claim 7, characterized in that: in step S5, N in the measured gas2Concentration C of ON2O＝C1-C2。
CN202111641235.5A 2021-12-29 2021-12-29 Electrochemical gas detection device and gas detection method Withdrawn CN114137055A (en)

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CN202111641235.5A CN114137055A (en) 2021-12-29 2021-12-29 Electrochemical gas detection device and gas detection method

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Application Number Priority Date Filing Date Title
CN202111641235.5A CN114137055A (en) 2021-12-29 2021-12-29 Electrochemical gas detection device and gas detection method

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CN114137055A true CN114137055A (en) 2022-03-04

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