Online measurement device and online measurement method

Abstract

The invention provides an on-line determination device and an on-line determination method, the on-line determination device comprises: a sample gas pipeline, the gas inlet of which is communicated with a chlorine gas production device; a gas inlet of the sample gas pretreatment device is communicated with a gas outlet of the sample gas pipeline, and the sample gas pretreatment device comprises a filtering assembly; a sample inlet of the gas chromatograph is communicated with a gas outlet of the sample gas pretreatment device; wherein in the extending direction from the gas inlet of the sample gas pipeline to the gas outlet of the sample gas pipeline, at least part of the sample gas pipeline is obliquely upwards arranged. By means of the technical scheme, the technical problem that in the prior art, an off-line chlorine measuring method is large in detection error can be solved.

Description

Technical Field

[0001] The present invention relates to a method for measuring chlorine, and in particular to an online measuring device and an online measuring method. Background Art

[0002] At present, the chlorine produced in the production of ion-exchange membrane caustic soda in the prior art is not suitable for analysis by explosion method and Ostwald gas analyzer because the purity of chlorine is relatively high and can generally reach 95%, and its impurity content is relatively low. Chlorine contains a small amount of hydrogen, oxygen, nitrogen and trace carbon dioxide, especially hydrogen. When the hydrogen content in chlorine reaches about 3.5%, under the influence of external conditions such as visible light, sparks or high temperature, direct chemical combination will cause explosion, so the impurity component content in chlorine is not only an important indicator of production process control, but also an indispensable safety technology control parameter. In the prior art, the components in chlorine can be analyzed by gas chromatograph, and the specific detection principle is: chlorine enters the chromatographic column quantitatively by a six-way valve, and each component is separated and enters the detector when flowing through the filling chromatographic column, so that the temperature of the metal wire in the detector decreases, the resistance value changes, and a corresponding signal is generated on the signal recording diagram. If a standard mixed gas with a known component content is used as a reference, the changes in these signals can be interpreted as the content of the measured gas. In the prior art, when using a gas chromatograph to analyze the composition of chlorine, an off-line determination method is often used, that is, the oxygen in the chlorine is manually collected and then the oxygen in the chlorine is introduced into the gas chromatograph for detection.

[0003] However, the following problems often exist when using such an offline measurement method: 1) The sampling tube is not sealed enough, and air infiltration may cause large deviations in the measured content. When the remaining gas is tested again, the reduced sample amount may increase the possibility of increased detection operation errors. 2) The operation of introducing gas into the chromatograph is cumbersome, and there are safety hazards such as chlorine leakage, which poses too great a safety risk for laboratory operations. 3) When the sample chlorine contains a lot of water, it is more corrosive to the instrument. 4) This method is a laboratory test, which requires sampling replacement time, sample transportation time, sample analysis time, and data reporting time. The overall analysis takes a long time, there are many operation links, the efficiency is not high, and the safety risk is high. Summary of the invention

[0004] The main purpose of the present invention is to provide an online measuring device and an online measuring method to solve the technical problem that the offline measuring method of chlorine in the prior art often has a large detection error.

[0005] In order to achieve the above object, according to one aspect of the present invention, an online determination device is provided, comprising:

[0006] A sample gas pipeline, wherein the gas inlet of the sample gas pipeline is connected to the chlorine production device;

[0007] A sample gas pretreatment device, wherein the gas inlet of the sample gas pretreatment device is connected to the gas outlet of the sample gas pipeline, and the sample gas pretreatment device comprises a filter assembly;

[0008] A gas chromatograph, wherein the sample inlet of the gas chromatograph is connected to the gas outlet of the sample gas pretreatment device;

[0009] Wherein, along the extending direction from the air inlet of the sample gas pipeline to the air outlet of the sample gas pipeline, at least a part of the sample gas pipeline is arranged to be inclined upward.

[0010] Further, the angle between at least part of the sample gas pipeline and the horizontal plane is α, 15°≤α≤30°; and / or,

[0011] There are multiple sample gas pipelines, and the multiple sample gas pipelines can be selectively connected or disconnected with the sample gas pretreatment device.

[0012] Furthermore, the online measuring device also includes:

[0013] A buffer tank is arranged between the sample gas pretreatment device and the gas outlet of the sample gas pipeline. The buffer tank has a buffer space, and a flow cross-section of the buffer space is larger than a flow cross-section of the sample gas pipeline.

[0014] Furthermore, the online measuring device also includes:

[0015] a gas-liquid separator, arranged between the buffer tank and the sample gas pretreatment device; and / or,

[0016] a switch valve, arranged between the gas-liquid separator and the sample gas pretreatment device, the switch valve being openable and closable; and / or,

[0017] A water cooling pipe is sleeved on the sample gas pipe, and the water cooling pipe is spaced apart from at least a portion of the sample gas pipe to form a water cooling heat exchange channel.

[0018] Furthermore, the filter assembly includes a plurality of filters, and the plurality of filters are connected and arranged in sequence; the sample gas pretreatment device also includes:

[0019] a vortex condenser, arranged between two adjacent filters; and / or,

[0020] A flow regulating valve is arranged between the filter assembly and the sampling port of the gas chromatograph, and the opening size of the flow regulating valve is adjustable.

[0021] Furthermore, the online measuring device also includes:

[0022] A communication module, wherein the communication module is connected to the gas chromatograph;

[0023] A control module, connected to the communication module by signal, the communication module is used to transmit the information detected by the gas chromatograph to the control module;

[0024] Wherein, the control module is connected with the gas chromatograph by signal so as to control the gas chromatograph through the control module.

[0025] Further, the sample gas pipeline is made of titanium alloy material; and / or,

[0026] The chlorine production device is installed in an electrolysis room, the sample gas pipeline is passed through the wall of the electrolysis room, and at least part of the sample gas pipeline is located outside the electrolysis room.

[0027] Furthermore, the gas chromatograph adopts a two-valve three-column structure, which includes a ten-way valve, a six-way valve, a Hastelloy column and two stainless steel columns. The gas chromatograph uses argon or nitrogen as a carrier gas.

[0028] According to another aspect of the present invention, an online measurement method is provided, which is applicable to the online measurement device provided above, and the online measurement method comprises:

[0029] Opening the air valve and carrier gas valve of the gas chromatograph of the online measuring device, and adjusting the air pressure through the air valve and adjusting the carrier gas pressure through the carrier gas valve;

[0030] Adjusting the inlet pressure and inlet flow rate of the gas chromatograph;

[0031] Setting the initial temperature of the column of the gas chromatograph, the initial temperature of the injector of the gas chromatograph and the initial temperature of the detector of the gas chromatograph, and controlling the column of the gas chromatograph, the injector of the gas chromatograph and the detector of the gas chromatograph to increase the temperature;

[0032] Setting the opening control conditions of the ten-way valve and the six-way valve of the gas chromatograph;

[0033] The sampling port of the gas chromatograph is controlled to perform sampling, collection and detection.

[0034] Furthermore, before controlling the sampling port of the gas chromatograph to perform sampling collection and detection, the online determination method further comprises: introducing a standard gas into the sampling port of the gas chromatograph and detecting the standard gas; and / or,

[0035] After controlling the sampling port of the gas chromatograph to perform sampling collection and detection, the online measurement method further includes: after completing the collection and detection of the sample gas, first turning off the power of the gas chromatograph, and continuously introducing the carrier gas into the gas chromatograph within a predetermined time.

[0036] By applying the technical solution of the present invention, the contamination of the gas chromatograph by liquid substances in the sample gas is effectively avoided through the inclined setting of the sample gas pipeline and the optimized design of the pretreatment device, and the purity of the sample gas collection is improved, thereby improving the accuracy and reliability of the test results. The titanium alloy sample gas pipeline adopted has excellent corrosion resistance and extends the service life of the device. At the same time, through the cooperation of the communication module and the control module, remote monitoring and data transmission are realized, which improves the convenience and safety of operation. The overall design enables the device to adapt to harsh industrial environments, ensures the continuity and stability of online measurement, and has significant benefits for the monitoring and optimization of the chlorine production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0038] Figure 1 A schematic diagram of the layout of an online determination device provided according to an embodiment of the present invention is shown;

[0039] Figure 2 It shows a schematic structural diagram of an online determination device provided according to an embodiment of the present invention;

[0040] Figure 3 A schematic structural diagram of a gas chromatograph provided according to an embodiment of the present invention is shown.

[0041] The above drawings include the following reference numerals:

[0042] 10. Sample gas pipeline;

[0043] 20. Sample gas pretreatment device; 21. Filter; 22. Vortex condenser; 23. Flow control valve;

[0044] 30. Gas chromatograph; 31. Ten-way valve; 32. Six-way valve;

[0045] 40. Buffer tank;

[0046] 50. Gas-liquid separator;

[0047] 60. Switch valve;

[0048] 70. Pipeline support;

[0049] 80. Chlorine production equipment. DETAILED DESCRIPTION

[0050] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0051] like Figures 1 to 3 As shown, one embodiment of the present invention provides an online measuring device, which includes a sample gas pipeline 10, a sample gas pretreatment device 20 and a gas chromatograph 30. The air inlet of the sample gas pipeline 10 is connected to the chlorine production device 80; the air inlet of the sample gas pretreatment device 20 is connected to the air outlet of the sample gas pipeline 10, and the sample gas pretreatment device 20 includes a filter assembly; the sample inlet of the gas chromatograph 30 is connected to the air outlet of the sample gas pretreatment device 20. Among them, along the extension direction from the air inlet of the sample gas pipeline 10 to the air outlet of the sample gas pipeline 10, at least part of the sample gas pipeline 10 is arranged to be inclined upward.

[0052] By adopting the online measuring device provided in this embodiment, by making at least part of the sample gas pipeline 10 tilt upward, it is convenient to make part of the water in the sample gas be separated under the action of gravity and reflux along the sample pipeline, thereby reducing the water content of the sample gas in the sample gas pipeline 10; by setting the sample gas pretreatment device 20 with a filter component, it is convenient to effectively filter the components other than chlorine in the sample gas, and the components other than chlorine mainly include a small amount of liquid water, tar and other substances, thereby reducing the influence of water and tar on the gas chromatograph 30, and facilitating the protection of the gas chromatograph 30. In addition, the above-mentioned online measuring device does not need to sample chlorine through a sampling tube and collect it in a predetermined container, but directly samples from the chlorine production device 80, ensuring the accuracy of sampling, and will not consider the problem of affecting the sampling accuracy due to the sealing problem of the sampling tube, and also reduces the situation of manual sampling, sampling operation and testing, and does not require manual participation in the whole process, which improves the safety and convenience of operation. Therefore, the online measurement device provided in this embodiment can solve the technical problem that the offline measurement method of chlorine in the prior art often has a large detection error.

[0053] In addition, the online measurement device provided in this embodiment can realize online detection, and there is no need for laboratory testing after sample collection. There will be no problems such as insufficient representativeness of sample gas, large detection errors, and delayed detection information. There is no need to introduce the sample gas into the gas chromatograph. The situation of high water content in chlorine gas can also be improved through the filtering component to avoid corrosion of the instrument by more water in chlorine gas. There is no need for laboratory testing, thereby improving the detection safety of sample gas (mainly chlorine gas) and realizing the functions of continuous detection and feedback.

[0054] Specifically, at least a portion of the sample gas pipeline 10 is supported by the pipeline support 70 .

[0055] Specifically, the sample gas coming out of the chlorine production device 80 can be called single-tank wet chlorine gas, which has a high water content and contains salt, alkali, tar and the like.

[0056] Specifically, at least part of the sample gas pipeline 10 has an angle α with the horizontal plane, 15°≤α≤30°, so that the moisture of the sample gas in the sample gas pipeline 10 can be better separated under the action of gravity and the separated moisture can be effectively ensured to flow back smoothly.

[0057] Specifically, there are multiple sample gas pipelines 10, and the multiple sample gas pipelines 10 can be selectively connected or disconnected with the sample gas pretreatment device 20. With such a structural setting, it is convenient to connect with a corresponding sample gas pipeline 10 according to actual production needs to detect the sample gas in the corresponding sample gas pipeline 10. Specifically, a corresponding switch valve 60 can be provided on each sample gas pipeline 10 or at the connection with each sample gas pipeline 10 to achieve the connection or disconnection of each sample gas pipeline 10 with the sample gas pretreatment device 20.

[0058] Specifically, the switch valve 60 is a pneumatic valve.

[0059] In this embodiment, the online measurement device further includes a buffer tank 40, which is disposed between the sample gas pretreatment device 20 and the gas outlet of the sample gas pipeline 10. The buffer tank 40 has a buffer space, and the flow cross section of the buffer space is larger than the flow cross section of the sample gas pipeline 10. With such a structural setting, it is possible to condense and reflux water with a greater probability while stabilizing the sample gas inlet pressure, thereby avoiding large fluctuations in the sample gas inlet pressure.

[0060] Specifically, the chlorine production device 80 generates chlorine by an electrolytic device using an electrolytic process. The chlorine produced by the electrolytic process contains saturated water, with a water content of about 20%. Simple filtration and separation cannot meet the requirements of long-term chromatographic detection. In this application, physical separation is achieved by setting the sample gas pipeline 10, so that the sample gas is continuously raised after being taken out, and the precipitated water is allowed to flow back naturally in combination with the principle of low process pressure. At the same time, most of the structures of the online detection device are separated from the electrolytic device to ensure that the sample gas pipeline 10 can fully condense and precipitate water and salt substances. Therefore, the pipeline is laid at an elevation angle of 15-30°, and a 50mm buffer tank 40 is added to stabilize the gas pressure fluctuation entering the gas chromatograph 30. Subsequently, it enters the chromatographic detection system after three-stage filtration and vortex condensation.

[0061] Specifically, the online measuring device further includes a gas-liquid separator 50, which is arranged between the buffer tank 40 and the sample gas pretreatment device 20. With such a structural arrangement, it is convenient to separate the liquid in the sample gas, thereby facilitating better reduction of the liquid in the sample gas and preventing the liquid from entering the gas chromatograph 30 and causing damage to the instrument.

[0062] Specifically, the gas-liquid separator 50 includes a plurality of bent pipes arranged back and forth, so that the sample gas flows in the longer bent pipes to achieve separation.

[0063] Specifically, the online measuring device further includes a switch valve 60, which is arranged between the gas-liquid separator 50 and the sample gas pretreatment device 20, and the switch valve 60 can be opened and closed. With such a setting, it is convenient to determine whether the sample gas separated by the gas-liquid separator 50 enters the sample gas pretreatment device 20 by turning on and off the switch valve 60, so as to facilitate operation.

[0064] Specifically, the online measuring device further includes a water cooling pipe, which is sleeved on the sample gas pipe 10, and the water cooling pipe is spaced apart from at least a portion of the sample gas pipe 10 to form a water cooling heat exchange channel. With such a structural arrangement, the sample gas can be cooled by the coolant introduced into the water cooling heat exchange channel, thereby avoiding the situation where the temperature of the sample gas entering the gas chromatograph 30 is too high.

[0065] In this embodiment, the filter assembly includes a plurality of filters 21, and the plurality of filters 21 are connected and arranged in sequence, so as to better improve the filtering effect on the sample gas.

[0066] Specifically, the filter 21 filters out solid or liquid substances in the sample gas by changing the pore size. The solid substances may be salt particles, and the liquid substances may include water and / or tar.

[0067] Specifically, the sample gas pretreatment device 20 further includes a vortex condenser 22, which is disposed between two adjacent filters 21. Thus, by disposing the vortex condenser 22, the liquid in the sample gas can be better separated, so as to better reduce the liquid component in the sample gas.

[0068] Specifically, the sample gas pretreatment device 20 further includes a flow regulating valve 23, which is arranged between the filter assembly and the sample inlet of the gas chromatograph 30, and the opening size of the flow regulating valve 23 is adjustable. With such a structural arrangement, the flow rate of the sample gas entering the gas chromatograph 30 can be adaptively adjusted, and the flow rate of the sample gas can be adjusted and controlled conveniently.

[0069] In this embodiment, the online determination device further includes a communication module and a control module, the communication module is connected to the gas chromatograph 30; the control module is connected to the communication module by signal, and the communication module is used to transmit the information detected by the gas chromatograph 30 to the control module; wherein the control module is connected to the gas chromatograph 30 by signal, so as to control the gas chromatograph 30 through the control module. With such a structural setting, it is convenient to transmit the detection result of the gas chromatograph 30 to the control module. Specifically, the control module also includes a display unit, and the detection result of the gas chromatograph 30 can be displayed by the display unit, so as to facilitate the staff to observe. In addition, the control module is connected to the switch valve 60 and the gas chromatograph 30, and the control module controls the switch of the switch valve 60 to determine whether the sample gas enters the sample gas pretreatment device 20 and the gas chromatograph 30, and the control module controls the opening and closing of the valve in the gas chromatograph 30. The flow control valve 23 is also connected to the control module, and the control module controls the opening size of the flow control valve 23. In this way, it is convenient to realize the automatic adjustment and control of the entire online determination device, reducing manual participation. In addition, since all structures of the online measuring device except the sample gas pipeline 10 can be effectively isolated from the sample gas production device, the safety of the use of the online measuring device is effectively guaranteed.

[0070] Specifically, the sample gas pipeline 10 is made of a titanium alloy material to prevent the sample gas pipeline 10 from being corroded by the sample gas, thereby ensuring the stability of the sample gas pipeline 10 .

[0071] Specifically, since the chlorine in the sample gas contains a lot of water, by selecting a corrosion-resistant titanium alloy pipe, the loss and replacement of chlorine can be reduced, and the water in the system can be effectively cooled and refluxed. Specifically, a Φ25mm diameter titanium alloy pipe can be used. A polytetrafluoroethylene hose can be used for connection within the pretreatment device and between the pretreatment device and the gas chromatograph 30.

[0072] Specifically, the chlorine production device 80 is installed in the electrolysis room, the sample gas pipeline 10 is installed on the wall of the electrolysis room, and at least part of the sample gas pipeline 10 is located outside the electrolysis room. With such a structural arrangement, at least part of the sample gas pipeline 10 of the online measurement device and the remaining structures can be arranged outside the electrolysis room, thereby facilitating better improvement of the setting safety of the online measurement device.

[0073] In this embodiment, the gas chromatograph 30 adopts a two-valve three-column structure, which includes a ten-way valve 31, a six-way valve 32, a Hastelloy column and two stainless steel columns, and the gas chromatograph 30 uses argon or nitrogen as a carrier gas. With such a setting, it is convenient to effectively ensure the detection accuracy of the gas chromatograph 30.

[0074] The sample gas pipeline 10 is led out from each single tank main pipe outlet pipeline (the single tank main pipe outlet pipeline is the outlet pipeline of the sample gas production device), and is arranged vertically upward, then passes through the wall of the electrolysis room and then continuously climbs at an elevation angle of 15-30 degrees. At the same time, a buffer tank 40 is added to allow the precipitated water and other impurities of the production system to settle and flow back to the corresponding single tank wet chlorine main pipe. The sample gas pipeline 10 can use a Φ25mm titanium pipeline. This arrangement must ensure that the air inlet of the sample gas pipeline 10 is located at a low position and the air outlet is located at a high position, so as to form a certain liquid level difference so that most of the precipitated water can continue to flow back to the main pipe outlet pipeline.

[0075] Subsequently, the sample gas is connected to the three-stage filtering and settling device (corresponding to the filtering component) in front of the gas chromatograph 30 to settle a small amount of liquid water, tar, etc. remaining in the wet chlorine gas. In order to ensure the adequacy of the replacement of the sample gas, the sample is arranged in two ways. One way (most of the sample gas) is directly discharged to the accident chlor-alkali absorption system, and the other way (a small part of the sample gas) enters the primary vortex condenser 22 in front of the online gas chromatograph 30 for treatment, so as to ensure that the sample gas temperature and water content meet the requirements of online gas chromatography analysis. The flow rate into the instrument is controlled at 20-50mL / min. After the sample gas is tested, it is discharged to the accident chlor-alkali absorption system. The system has a slight negative pressure and attention should be paid to the pressure.

[0076] The gas chromatograph 30 includes a detector, and can effectively separate five components through a 2-valve 3-column configuration. Column 1 is made of a Hastelloy column (shincarbon filler, corresponding to a cross-active carbon filler), which is used to pre-separate the sample gas and back-blow out the unnecessary components from the chromatogram; column 2 is a stainless steel column of a certain material (using a molecular sieve stationary phase), which is used to analyze hydrogen, oxygen, nitrogen, and methane components; column 3 is a stainless steel column of another material (using POLT Q filler, which is a copolymer of ethylstyrene and divinylbenzene, corresponding to a plastic stationary phase), which is used to analyze carbon dioxide components. Valve 1 of the 2 valves is a 10-way valve (10-way valve 31), and valve 2 of the 2 valves is a 6-way valve (6-way valve 32). The gas chromatograph 30 in this embodiment uses argon as the carrier gas. If there is no metering requirement for nitrogen in the system, nitrogen can also be used as the carrier gas.

[0077] By using the online measurement device provided in this embodiment, the single-tank wet chlorine is pre-treated and improved to achieve continuous gas entry into the chromatograph, and then the hydrogen, oxygen, nitrogen, and carbon dioxide components in the chlorine are quantitatively measured using online gas chromatography, and the chlorine content is obtained by subtraction to accurately understand the process control of the production system. The analysis results are then connected to the production distributed control system (corresponding to the control module) through the Modbus protocol (serial communication protocol), which can not only complete the online measurement of samples, but also realize the implementation of safe production. The data is mastered and controlled, and the production efficiency and safety factor are improved.

[0078] Specifically, the outlet pipeline pressure is generally around 20KPa, while the inlet gas flow rate of the gas chromatograph 30 is generally 20-50ml / min. The inner diameter of the inlet pipeline is selected to be 25mm, and the inner diameter of the buffer tank 40 is 50mm, so as to make it more likely to condense and reflux the water while stabilizing the influence of inlet pressure fluctuation. The sample gas temperature of the outlet pipeline is 80℃, and it passes through the electrolysis workshop and is cooled by ambient air to precipitate a large amount of liquid. When the ambient temperature exceeds 40 degrees Celsius, the sample gas pipeline 10 can be cooled by general cooling or air cooling.

[0079] Another embodiment of the present invention provides an online measurement method, which is applicable to the online measurement device provided above, and the online measurement method includes: opening the air valve and carrier gas valve of the gas chromatograph 30 of the online measurement device, and adjusting the air pressure through the air valve and adjusting the carrier gas pressure through the carrier gas valve; adjusting the inlet pressure and inlet flow of the gas chromatograph 30; setting the initial temperature of the column of the gas chromatograph 30, the initial temperature of the injector of the gas chromatograph 30 and the initial temperature of the detector of the gas chromatograph 30, and controlling the column of the gas chromatograph 30, the injector of the gas chromatograph 30 and the detector of the gas chromatograph 30 to increase the temperature; setting the opening control conditions of the ten-way valve 31 and the six-way valve 32 of the gas chromatograph 30; and controlling the injection port of the gas chromatograph 30 for sampling, collection and detection.

[0080] The online measurement method provided in this embodiment can facilitate the automatic collection and detection of the components of the sample gas, without the need to collect separately and then send it to the gas chromatograph 30 for analysis, thereby improving the accuracy of the detection. In addition, the specific steps of the above-mentioned online measurement method can facilitate the effective guarantee of the smooth collection and detection of the sample gas.

[0081] Specifically, before controlling the sampling port of the gas chromatograph 30 for sampling and collection detection, the online determination method further includes: introducing a standard gas into the sampling port of the gas chromatograph 30, and detecting the standard gas. The gas chromatograph 30 collects and calculates quantitatively using an external standard valve, so it is necessary to introduce a standard gas to determine the correction factor. This method can facilitate the accurate calculation of the sampler content.

[0082] Specifically, after controlling the sampling port of the gas chromatograph 30 to perform sampling collection and detection, the online measurement method further includes: after completing the collection and detection of the sample gas, first turning off the power of the gas chromatograph 30, and continuously introducing the carrier gas into the gas chromatograph 30 for a predetermined time. By adopting such a method, it is possible to cool down the gas chromatograph 30 by continuously introducing the carrier gas.

[0083] When there are multiple sample gas pipelines, one sample gas pipeline may start collecting gas at a first preset time, and another sample gas pipeline may start collecting gas at a second preset time.

[0084] In this embodiment, the standard gas conditions of the gas chromatograph 30 are: 1% hydrogen, 1% oxygen, 1% carbon monoxide, 1% carbon dioxide, 1% methane, and argon as a balance gas. Detection chromatographic conditions: quantitative loop: 0.5mL, bridge current: 70 mA. Temperature control conditions are: control the temperature of the sample gas to 70°C, control the temperature of the column furnace to 70°C, and control the temperature of the detector to 100°C. The pressure parameters of the specific scheme are: the carrier gas of the sample gas is 21PSI argon, and the corresponding air (air is the power source of the six-way valve 32 and the ten-way valve 31 of the gas chromatograph 30, which is the instrument gas) is 18PSI. When the gas chromatograph 30 is started for detection operation, the connection state of the ten-way valve 31 is switched at 0.01min after startup, the connection state of the six-way valve 32 is switched at 2min after startup, and then the connection state of the ten-way valve 31 is switched again at the 6th minute after startup, and the connection state of the six-way valve 32 is switched again at 12min after startup. The peak times of the corresponding components of the standard gas are: after starting the gas chromatograph, the peak time of hydrogen is 2.31min (corresponding to the startup detection time defined as zero time), the peak time of oxygen is 4.18min, the peak time of nitrogen is 4.83min, the peak time is 2.31min, the peak time of methane is 6.47min, and the peak time of carbon dioxide is 7.08min.

[0085] Specifically, the specific steps of the online detection method in this embodiment include the following:

[0086] (1) Open the air and carrier gas (argon) valves, adjust the instrument air pressure to about 0.5 MPa, and adjust the carrier gas argon pressure to about 0.5 MPa.

[0087] (2) Turn on the gas chromatograph 30, adjust the inlet pressure and flow rate, control the pressure at about 0.15 MPa, and the flow rate at about 200 mL / min. Set the column temperature to 70°C, the injector temperature to 70°C, and the detector temperature to 100°C. Click the start temperature control button, the instrument heats up, and when the state is ready and stable, set the bridge flow to 70 mA.

[0088] (3) Setting valve control conditions, specifically: when starting the gas chromatograph 30 for detection, the connection state of the ten-way valve 31 is switched at 0.01 min after the start-up, the connection state of the six-way valve 32 is switched at 2 min after the start-up, and then the connection state of the ten-way valve 31 is switched again at 6 min after the start-up, and the connection state of the six-way valve 32 is switched again at 12 min after the start-up.

[0089] (4) Standard gas injection and calibration: switch the injection port to the standard gas mode, wait for the baseline to stabilize and prepare for injection analysis. Connect the standard gas and adjust the flow rate of the standard gas to about 200 mL / min (or 150 is also OK, to ensure that the standard gas and sample injection are the same). Click "Start Collection", the injection volume is 0.5 mL, and the detection time is about 8 min.

[0090] (5) Sample test: Switch the inlet to the sample gas mode and start the collection. Continuous switching collection will be carried out according to the corresponding time switching logic. Repeat this process to switch and detect the chlorine gas in the production unit.

[0091] Specifically, when the online measurement device in this embodiment includes multiple sample gas pipelines 10, the corresponding time switching logic is to start the online measurement device, process and collect sample gas in one sample gas pipeline 10 within a first preset time period, and then perform detection, complete the detection of the sample gas through the gas chromatograph 30 within a second preset time period, and then perform detection on the next sample gas pipeline 10. Specifically, the first preset time period is 30 minutes, and the second preset time period is 30 minutes.

[0092] (6) Shutdown: When the production equipment is shut down or the instrument is inspected and maintained, please turn off the power first, then pass the carrier gas for 30 minutes to cool the instrument down, and finally close the carrier gas valve to complete the inspection.

[0093] For carrier gas, a design of connecting multiple carrier gas bottles and a non-stop diverter valve is adopted to achieve non-stop replacement of gas bottles and automatic switching due to insufficient gas bottle pressure.

[0094] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: it is suitable for the rapid and continuous detection application in the current continuous industrialized efficient production, reduces the manual sampling link, shortens the analysis time, and improves production safety. The increase of the sample gas pretreatment device realizes the preliminary gas-liquid separation through the air intake pipeline and the instrument layout, and then controls the pneumatic valve switching through the industrial software to realize the gas circulation switching of the multi-channel sample gas, and then removes the salt, alkali, water, tar and other impurities in the wet chlorine gas through the pretreatment equipment such as gas-liquid separator, filter, vortex condenser, etc., so that the wet chlorine gas meets the requirements of accurate and stable determination of online chromatography, reduces maintenance costs, and realizes the purpose of online detection. After adopting gas chromatography and combining the pretreatment device, the content of hydrogen, oxygen, nitrogen, methane and carbon dioxide components in chlorine can be continuously and accurately quantified. The data is transmitted to the production control system (corresponding to the control module) in real time through the communication module to realize online monitoring and regulation.

[0095] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0096] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0097] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0098] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0099] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An online measuring device, characterized in that: include: A sample gas pipeline (10), wherein the gas inlet of the sample gas pipeline (10) is connected to the chlorine production device; A sample gas pretreatment device (20), wherein the gas inlet of the sample gas pretreatment device (20) is connected to the gas outlet of the sample gas pipeline (10), and the sample gas pretreatment device (20) comprises a filter assembly; A gas chromatograph (30), wherein the sample inlet of the gas chromatograph (30) is connected to the gas outlet of the sample gas pretreatment device (20); Wherein, along the extension direction from the air inlet of the sample gas pipeline (10) to the air outlet of the sample gas pipeline (10), at least part of the sample gas pipeline (10) is arranged obliquely upward.

2. The online measuring device according to claim 1, characterized in that: The angle between at least a portion of the sample gas pipeline (10) and the horizontal plane is α, 15°≤α≤30°; and / or, There are a plurality of sample gas pipelines (10), and the plurality of sample gas pipelines (10) can be selectively connected to or disconnected from the sample gas pretreatment device (20).

3. The online measuring device according to claim 1, characterized in that: The online measuring device also includes: A buffer tank (40) is arranged between the sample gas pretreatment device (20) and the gas outlet of the sample gas pipeline (10), wherein the buffer tank (40) has a buffer space, and a flow cross section of the buffer space is larger than a flow cross section of the sample gas pipeline (10).

4. The online measuring device according to claim 3, characterized in that: The online measuring device also includes: a gas-liquid separator (50), arranged between the buffer tank (40) and the sample gas pretreatment device (20); and / or, a switch valve (60) disposed between the gas-liquid separator (50) and the sample gas pretreatment device (20), wherein the switch valve (60) can be opened and closed; and / or, A water cooling pipe, wherein the water cooling pipe is sleeved on the sample gas pipe (10), and the water cooling pipe and at least a portion of the sample gas pipe (10) are spaced apart to form a water cooling heat exchange channel.

5. The on-line measuring device according to claim 1, characterized in that: The filter assembly comprises a plurality of filters (21), wherein the plurality of filters (21) are connected and arranged in sequence; the sample gas pretreatment device (20) further comprises: a vortex condenser (22), arranged between two adjacent filters (21); and / or, A flow regulating valve (23) is arranged between the filter assembly and the sampling port of the gas chromatograph (30), and the opening size of the flow regulating valve (23) is adjustable.

6. The online measuring device according to claim 1, characterized in that: The online measuring device also includes: a communication module, the communication module being connected to the gas chromatograph (30); a control module, connected to the communication module by signal, the communication module being used to transmit information detected by the gas chromatograph (30) to the control module; The control module is signal-connected to the gas chromatograph (30) so as to control the gas chromatograph (30) through the control module.

7. The on-line measuring device according to claim 1, characterized in that: The sample gas pipeline (10) is made of a titanium alloy material; and / or, The chlorine production device is installed in an electrolysis room, the sample gas pipeline (10) is passed through the wall of the electrolysis room, and at least part of the sample gas pipeline (10) is located outside the electrolysis room.

8. The on-line measuring device according to claim 1, characterized in that: The gas chromatograph (30) adopts a two-valve three-column structure, which includes a ten-way valve, a six-way valve, a Hastelloy column and two stainless steel columns. The gas chromatograph (30) uses argon or nitrogen as a carrier gas.

9. An online determination method, characterized in that: The online measurement device according to any one of claims 1 to 8, wherein the online measurement method comprises: Opening the air valve and carrier gas valve of the gas chromatograph of the online measuring device, and adjusting the air pressure through the air valve and adjusting the carrier gas pressure through the carrier gas valve; Adjusting the inlet pressure and inlet flow rate of the gas chromatograph; Setting the initial temperature of the column of the gas chromatograph, the initial temperature of the injector of the gas chromatograph and the initial temperature of the detector of the gas chromatograph, and controlling the column of the gas chromatograph, the injector of the gas chromatograph and the detector of the gas chromatograph to increase the temperature; Setting the opening control conditions of the ten-way valve and the six-way valve of the gas chromatograph; The sampling port of the gas chromatograph is controlled to perform sampling, collection and detection.

10. The online determination method according to claim 9, characterized in that: Before controlling the sampling port of the gas chromatograph to perform sampling collection and detection, the online determination method further comprises: introducing a standard gas into the sampling port of the gas chromatograph and detecting the standard gas; and / or, After controlling the sampling port of the gas chromatograph to perform sampling collection and detection, the online measurement method further includes: after completing the collection and detection of the sample gas, first turning off the power of the gas chromatograph, and continuously introducing the carrier gas into the gas chromatograph within a predetermined time.

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