Table type non-methane total hydrocarbon analyzer

Abstract

The invention relates to the technical field of gas detection, and particularly discloses a table type non-methane total hydrocarbon analyzer which comprises an analyzer body, the analyzer body comprises an automatic sample injection module, and the automatic sample injection module comprises multiple groups of sample injection ports, a multi-way selector valve, a sample injection pump and a quantitative loop; the independent sample introduction module is provided with a plurality of groups of gas inlets and is used for introducing gas for single detection; an inlet gas dilution module; a hydrogen generator; an air purification module; the chromatographic separation module comprises a total hydrocarbon chromatographic column and a methane chromatographic column and is used for allowing total hydrocarbon components to pass through and separating methane in a sample; the analyzer provided by the invention is high in integration level and convenient to operate; the automatic sample injection unit is integrally designed, an external pipeline is not needed, automatic switching sample injection of samples is realized, manual intervention is reduced, and the operation complexity is reduced; an air inlet dilution module is arranged inside, the dilution ratio can be adjusted from 1: 1 to 1: 100, additional external dilution equipment is not needed, and pollution and errors in the pretreatment process are avoided; no high-pressure gas cylinder is needed, and the detection precision is high.

Description

Technical Field

[0001] This invention belongs to the field of gas detection technology, specifically relating to a benchtop non-methane total hydrocarbon analyzer. Background Technology

[0002] Non-methane hydrocarbons (NMHC) are a core indicator of volatile organic compounds (VOCs). In the atmosphere, they react with nitrogen oxides under sunlight to form photochemical smog, leading to increased ozone concentrations, reduced visibility, and toxic effects on the human respiratory and nervous systems. They are a key indicator for monitoring ambient air quality and controlling industrial pollution emissions in my country. With increasingly stringent environmental regulations, environmental monitoring stations, industrial parks, and petrochemical and chemical enterprises have significantly increased their demands for the timeliness, accuracy, and convenience of NMHC testing. Benchtop NMHC analyzers, combining laboratory-level accuracy with rapid on-site analysis capabilities, have become the mainstream testing equipment. Currently, the commonly used technical approach is "gas chromatography separation + flame ionization detector (FID) detection." However, existing instruments still have many technical shortcomings and cannot meet diverse needs.

[0003] Regarding the sample introduction system, most instruments are designed with a single sample interface. When conducting batch testing, it is necessary to frequently change the sample container manually, which is cumbersome and prone to introducing contamination or leakage during the transfer process, increasing the detection error. Although some instruments integrate multi-injection functions, they share the flow path for standard gas and sample injection, which can easily cause cross-contamination. Furthermore, they cannot simultaneously meet the requirements of "batch multi-well continuous detection" and "rapid analysis of single emergency samples", thus limiting their applicable scenarios.

[0004] The chromatographic separation system has obvious design flaws: some instruments use redundant configurations of multiple chromatographic columns, which, although attempting to accommodate the detection of multiple components, lack specificity for the separation of NMHC "total hydrocarbons-methane", resulting in lengthy processes and increased energy consumption; some instruments use only a single chromatographic column, which has weak separation capability for complex matrix samples such as industrial waste gases containing CO, CO2, and low-carbon alkanes, with the resolution of methane and impurity components often below 1.2, failing to meet the requirements for quantitative accuracy; and some total hydrocarbon chromatographic columns do not have inert inner walls, resulting in severe adsorption of polar components such as alkenes and aldehydes, which not only causes peak tailing but also shortens column life and increases maintenance costs.

[0005] In terms of gas supply, FID requires high-purity hydrogen and clean air. Existing instruments generally rely on high-pressure gas cylinders: transportation and storage require strict safety regulations, and there are risks of leakage and explosion during on-site testing; the limited capacity of gas cylinders requires frequent replacement, which increases costs and interrupts the testing process, and the purity of the gas is affected by storage time and transportation conditions, which can easily lead to fluctuations in test data.

[0006] The control and temperature control systems are not intelligent and have low accuracy: the control units can only execute basic instructions and lack automatic calibration, fault diagnosis and in-depth data analysis functions. The calibration curves and calculation results need to be drawn manually, which is cumbersome and prone to human error. Most of them adopt single-zone overall temperature control and cannot independently adjust the temperature according to the different requirements of total hydrocarbon column (requiring low temperature rapid sample passage) and methane column (requiring high temperature precise separation), which leads to a decrease in the separation efficiency of one component and affects the accuracy of detection.

[0007] In summary, existing benchtop non-methane total hydrocarbon analyzers have significant shortcomings in terms of sample introduction flexibility, separation efficiency, gas source safety, detection stability, and intelligent control, making it difficult to meet user needs. Summary of the Invention

[0008] The purpose of this invention is to provide a benchtop non-methane total hydrocarbon analyzer to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A benchtop non-methane total hydrocarbon analyzer includes: The analyzer body includes an automatic sample injection module, which comprises multiple injection ports, a multi-way selector valve, an injection pump, and a quantitative loop. The multi-way selector valve and injection ports are one-to-one, used for automatic switching of multiple sample injections. The injection pump is used to extract samples from the rear end and enter the quantitative loop through a designated injection port. The quantitative loop includes a total hydrocarbon column quantitative loop and a methane column quantitative loop, and the outlets are connected to the total hydrocarbon column and methane column of the chromatographic separation module respectively through switching valves. The independent sample introduction module is equipped with multiple gas inlets for introducing gas for a single test, thus enabling gas introduction. The intake dilution module is used to dilute the gas. A hydrogen generator is used to produce high-purity hydrogen, providing an independent hydrogen source for the FID detector; The air purification module is used to purify the ambient air and provide an independent air source for the FID detector. The chromatographic separation module includes a total hydrocarbon chromatographic column and a methane chromatographic column, which is a dual-column chromatographic separation module used for passing total hydrocarbon components through and separating methane from the sample; The FID detector is connected to the chromatographic separation module. When the analyte passes through the FID detector, it generates a special electrical signal for qualitative and quantitative analysis of the compound. The multi-zone temperature control module includes a column oven, a switching valve temperature control unit, and a detector temperature control unit, used for temperature control; The pressure control module includes two sets of EPC electronic pressure controllers for controlling the flow rates of hydrogen, air, and nitrogen. The inlet of one set of EPC electronic pressure controllers is connected to the hydrogen generator, air purification module, and independent sample injection module via a gas pipeline, and the outlet is connected to the FID detector via a gas pipeline. The inlet of the other set of EPC electronic pressure controllers is connected to the independent sample injection module via a gas pipeline, and the outlet is connected to the switching valve. The intelligent control module is electrically connected to the automatic sample injection module, the independent sample injection module, the gas dilution module, the hydrogen generator, the air purification module, the chromatographic separation module, the FID detector, the multi-zone temperature control module, and the pressure control module, respectively, and plays the role of controlling the operation of each module.

[0010] Preferably, the injection port is configured as a sixteen-position injection port, that is, there are sixteen groups of injection ports, and the multi-way selection valve is configured as a sixteen-way selection valve, with each of the sixteen selection valves corresponding to one of the sixteen injection ports, for automatic switching of multiple groups of samples for injection.

[0011] Preferably, the independent sample introduction module includes an external nitrogen inlet, an external air inlet, an external hydrogen inlet, an external standard gas inlet, and a dilution sample inlet. The external nitrogen inlet, the external air inlet, the external hydrogen inlet, the external standard gas inlet, and the dilution sample inlet are sequentially arranged on the outside of the analyzer body, respectively for connecting nitrogen, air, hydrogen, standard gas, and sample gas for a single detection, to realize gas introduction.

[0012] Preferably, the gas dilution module includes a mixing chamber, a dilution gas inlet, a sampling pump, and a mass flow controller. Two sets of mass flow controllers are configured, each a high-precision MFC flow meter. One set of mass flow controllers has its inlet and outlet connected to the external nitrogen inlet and the mixing chamber, respectively. The inlet of the other set of mass flow controllers is connected to a three-way selector valve, with the other two ends connected to the sampling pump and the external standard gas inlet, respectively. The sampling pump is connected to the dilution sample inlet. The outlet of the other set of mass flow controllers is connected to the mixing chamber. The mixing chamber has a volume of 10 mL, and its inner wall is inertized to prevent sample adsorption.

[0013] Preferably, the hydrogen generator is configured as a proton exchange membrane electrolysis water type, which is a hydrogen generator in the prior art. It removes water through a gas-water separator and silica gel, and the outlet is connected to the hydrogen inlet of the pressure control module through a pipeline. The air purification module comprises two parts: an air pump and an air purification device. The air purification device includes a high-temperature hydrocarbon removal unit, a silica gel dehydration unit, and a molecular sieve impurity removal unit connected in series. It is an existing air purification device. The inlet is connected to the air pump, and the outlet is connected to the air inlet of the pressure control module.

[0014] Preferably, the total hydrocarbon chromatographic column is a silanized stainless steel empty column, used for the non-retention passage of total hydrocarbon components; The methane-specific chromatographic column is an inert stainless steel packed column, used for the specific separation of methane in samples; The outlet of the mixing chamber of the gas dilution module is connected to an injection loop via a three-way valve and a switching valve. The injection loop is connected to the inlet of the methane column and the total hydrocarbon column via the switching valve. The outlets of the methane column and the total hydrocarbon column are both connected to the FID detector via the switching valve 13.

[0015] Preferably, the FID detector includes a combustion chamber, an ignition assembly, an ion collecting electrode, and a signal processing unit. It is a high-sensitivity FID detector in the prior art. The hydrogen inlet and air inlet of the FID detector are respectively connected to the hydrogen and air outlets of a set of EPC electronic pressure controllers to ensure the accuracy and repeatability of the detection data.

[0016] Preferably, the column oven has two independent temperature control zones, which correspond one-to-one with the total hydrocarbon column and the methane column, respectively. The temperature control range is 30-200℃, the temperature control accuracy is ±0.5℃, and platinum resistance temperature measurement is used. The switching valve temperature control unit is used to control the temperature of the switching valve, ensuring that the switching valve maintains a high temperature and avoiding the adsorption of the target compound. The temperature control range is 30-200℃, and the temperature control accuracy is ±0.5℃. Platinum resistance thermometer is used to measure the temperature, which can achieve temperature control for the switching valve temperature control unit in the prior art. The detector temperature control unit encloses the combustion chamber of the FID detector, with a temperature control range of 180-350℃ and a temperature control accuracy of ±0.5℃. The detector temperature control unit is equipped with an insulation layer made of aluminum silicate cotton with a thickness of 20mm to reduce heat loss. It can be used as a detector temperature control unit in the prior art to achieve temperature control.

[0017] Preferably, the pressure control module includes two sets of EPC electronic pressure controllers, one set of which serves as a hydrogen pressure control unit and an air pressure control unit, and the other set of which serves as a nitrogen pressure control unit. The EPC electronic pressure controller includes a circuit board, a pressure sensor, an air inlet, an air outlet proportional valve, and an air resistance. Gas flows in through the air inlet, and the circuit board controls the proportional valve to reach the specified pressure, which is then output through the air outlet via the air resistance. The pressure sensor provides feedback on the real-time pressure. The inlet of the hydrogen pressure control unit is connected to the outlet of the hydrogen generator and the external hydrogen inlet in the independent sample injection module, and the outlet of the hydrogen pressure control unit is connected to the FID detector to control the hydrogen supply. The inlet of the air pressure control unit is connected to the outlet of the air purification module and the external air inlet in the independent sample injection module. The outlet of the air pressure control unit is connected to the FID detector to control the air supply. The inlet of the nitrogen pressure control unit is connected to the external nitrogen inlet in the independent injection module, and the outlet of the nitrogen pressure control unit is connected to a switching valve, which is a 14-way switching valve. The switching valve is connected to the dual-column chromatography separation module to provide nitrogen carrier gas for chromatographic analysis and control the nitrogen flow rate.

[0018] Preferably, the intelligent control module includes a main control board, a control switch, a touch screen, a data storage module, a communication interface, and a fault diagnosis unit. This intelligent control module is a control system in the prior art, which will not be described in detail here. The main control board is electrically connected to the automatic sample injection module, the independent sample injection module, the gas dilution module, the hydrogen generator, the air purification module, the chromatographic separation module, the FID detector, the multi-zone temperature control module, the pressure control module, and the data storage module, respectively, and is used to control sample injection switching, dilution ratio, chromatographic separation, detection signal acquisition, and data processing. The fault diagnosis unit can monitor abnormalities in flow rate, temperature, and pressure, and trigger audible and visual alarms. It can be a fault diagnosis unit in the prior art.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. High integration and convenient operation: The automatic sample introduction unit is designed as an integrated unit, eliminating the need for external tubing and enabling automatic sample switching and introduction, reducing manual intervention and operational complexity; the control unit supports touch operation and automatic data processing, simplifying the detection process to "sample loading - parameter setting - detection start", which can be completed by a single person. 2. Wide applicable concentration range: Built-in air intake dilution module with an adjustable dilution ratio of 1:1 to 1:100, capable of detecting non-methane total hydrocarbons from 0.1 mg / m³ (ambient air) to 10000 mg / m³ (high concentration industrial waste gas), eliminating the need for additional external dilution equipment and avoiding pollution and errors during the pretreatment process; 3. No need for high-pressure gas cylinders, safe and convenient: The hydrogen generator produces high-purity hydrogen, and the air purification module treats the ambient air, replacing traditional high-pressure hydrogen cylinders and air cylinders. This eliminates the safety risks of transporting and storing gas cylinders, and there is no need to frequently replace gas cylinders, reducing operating costs (only periodic replenishment of deionized water and replacement of purification filter cartridges are required). 4. High detection accuracy: It adopts a high-precision mass flow controller (flow accuracy ±1% FS), a high-selectivity chromatographic column (methane resolution ≥1.5) and a high-sensitivity FID detector (detection limit ≤0.05mg / m³) to ensure the accuracy and repeatability of detection data (relative standard deviation RSD ≤3%). Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the present invention. Figure 3 This is a rear view of the internal structure of this invention patent; Figure 4 This is a right-side view of the present invention patent; Figure 5 This is a left-side view of the present invention patent; Figure 6 This is a schematic diagram of the gas path connection during sample injection according to the present invention patent. Figure 7 This is a schematic diagram of the gas path connection during the measurement state after sample injection, as shown in this invention patent. Figure 8 This is a schematic diagram of the gas path connection during sample dilution injection according to the present invention patent. Figure 9 This is a schematic diagram of the gas path connection during standard gas injection according to the present invention patent. In the diagram: 1. Control switch; 2. Sixteen-position injection port; 3. Sixteen-way selector valve; 4. EPC electronic pressure controller; 5. Valve motor; 6. MFC flow meter; 7. Intelligent control module; 8. Hydrogen generator; 9. Air purification module; 10. Independent injection module; 11. FID detector; 12. Chromatographic separation module; 13. Fourteen-way switching valve; 14. External nitrogen inlet; 15. External air inlet; 16. External hydrogen inlet; 17. External standard gas inlet; 18. Dilution sample inlet; 19. Touch screen display. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figures 1-9 As shown, a benchtop non-methane total hydrocarbon analyzer includes: The analyzer body includes an automatic sample injection module, which comprises multiple injection ports, a multi-way selector valve, an injection pump, and a quantitative loop. The multi-way selector valve and the injection ports are one-to-one, used for automatic switching of multiple sample injections. The injection pump is used to extract samples from the rear end and enter the quantitative loop through a designated injection port. The quantitative loop includes a total hydrocarbon column quantitative loop and a methane column quantitative loop, and the outlets are respectively connected to the total hydrocarbon chromatographic column and the methane chromatographic column of the chromatographic separation module 12 through a switching valve 13. The independent sample introduction module 10 is equipped with multiple gas inlets for introducing gas for a single detection, thus realizing gas introduction. The intake dilution module is used to dilute the gas. Hydrogen generator 8 is used to produce high-purity hydrogen; providing an independent hydrogen source for FID detector 11; Air purification module 9 is used to extract and purify ambient air, providing an independent air source for FID detector 11; The chromatographic separation module 12 includes a total hydrocarbon chromatographic column and a methane chromatographic column, which is a dual-column chromatographic separation module 12, used for passing total hydrocarbon components through and separating methane from the sample; FID detector 11 is connected to chromatographic separation module 12. When the analyte passes through FID detector 11, it generates a special electrical signal for qualitative and quantitative analysis of the compound. The multi-zone temperature control module includes a column oven, a switching valve temperature control unit, and a detector temperature control unit, used for temperature control; The pressure control module includes two sets of EPC electronic pressure controllers 4, which are used to control the flow rates of hydrogen, air, and nitrogen. The inlet of one set of EPC electronic pressure controllers is connected to the hydrogen generator 8, the air purification module 9, and the independent sample injection module 10 through a gas pipeline, and the outlet is connected to the FID detector 11 through a gas pipeline. The inlet of the other set of EPC electronic pressure controllers is connected to the independent sample injection module 10 through a gas pipeline, and the outlet is connected to the switching valve 13. The intelligent control module 7 is electrically connected to the automatic sample injection module, the independent sample injection module 10, the gas dilution module, the hydrogen generator 8, the air purification module 9, the chromatographic separation module 12, the FID detector 11, the multi-zone temperature control module, and the pressure control module, respectively, and plays the role of controlling the operation of each module.

[0023] Furthermore, the injection port is set to a sixteen-position injection port 2, that is, there are sixteen groups of injection ports. The multi-way selection valve is set to a sixteen-way selection valve 3, which corresponds one-to-one with the sixteen-position injection port 2 and is used for automatic switching injection of multiple groups of samples.

[0024] Furthermore, the independent sample introduction module 10 includes an external nitrogen inlet 14, an external air inlet 15, an external hydrogen inlet 16, an external standard gas inlet 17, and a dilution sample inlet 18. The external nitrogen inlet 14, external air inlet 15, external hydrogen inlet 16, external standard gas inlet 17, and dilution sample inlet 18 are sequentially arranged on the outside of the analyzer body, which are used to connect nitrogen, air, hydrogen, standard gas, and sample gas for a single detection, respectively, to realize gas introduction.

[0025] Furthermore, the gas dilution module includes a mixing chamber, a dilution gas inlet, a sampling pump, and a mass flow controller. Two sets of mass flow controllers are configured, each a high-precision MFC flow meter 6. One set of mass flow controllers has its inlet and outlet connected to the external nitrogen inlet 14 and the mixing chamber, respectively. The inlet of the other set of mass flow controllers is connected to a three-way selector valve, with the other two ends connected to the sampling pump and the external standard gas inlet 17, respectively. The sampling pump is connected to the dilution sample inlet 18. The outlet of the other set of mass flow controllers is connected to the mixing chamber, which has a volume of 10 mL. The inner wall of the mixing chamber is inertized to prevent sample adsorption.

[0026] Furthermore, the hydrogen generator 8 is configured as a proton exchange membrane electrolysis water type, which is the hydrogen generator 8 in the prior art. It removes water through a gas-water separator and silica gel, and the outlet is connected to the hydrogen inlet of the pressure control module through a pipeline. The air purification module 9 includes an air pump and an air purification device. The air purification device includes a high-temperature hydrocarbon removal unit, a silica gel dehydration unit, and a molecular sieve impurity removal unit connected in series. It is an air purification device in the prior art. The inlet is connected to the air pump, and the outlet is connected to the air inlet of the pressure control module.

[0027] Furthermore, the total hydrocarbon chromatographic column is a silanized stainless steel empty column, used for the non-retention passage of total hydrocarbon components; The methane-specific chromatographic column is an inert stainless steel packed column used for the specific separation of methane in samples; The outlet of the mixing chamber of the gas dilution module is connected to an injection loop via a three-way valve and a switching valve 13. The injection loop is connected to the inlet of the methane column and the total hydrocarbon column via the switching valve 13. The outlets of the methane column and the total hydrocarbon column are both connected to the FID detector 11 via the switching valve 13.

[0028] Furthermore, the FID detector 11 includes a combustion chamber (made of quartz to avoid carbon deposition), an ignition assembly (automatic ignition), an ion collecting electrode (gold-plated to improve conductivity), and a signal processing unit. It is a high-sensitivity FID detector 11 in the prior art. The hydrogen inlet and air inlet of the FID detector 11 are respectively connected to the hydrogen and air outlets of a set of EPC electronic pressure controllers 4 to ensure the accuracy and repeatability of the detection data.

[0029] Furthermore, the column oven has two independent temperature control zones, corresponding one-to-one with the total hydrocarbon column and the methane column, respectively. The temperature control range is 30-200℃, the temperature control accuracy is ±0.5℃, and the temperature is measured by a platinum resistance thermometer (PT100). The switching valve temperature control unit is used to control the temperature of the switching valve 13, ensuring that the switching valve maintains a high temperature and avoiding the adsorption of the target compound. The temperature control range is 30-200℃, and the temperature control accuracy is ±0.5℃. It uses platinum resistance (PT100) temperature measurement, which can achieve temperature control for the switching valve temperature control unit in the existing technology. The detector temperature control unit encloses the combustion chamber of the FID detector 11, with a temperature control range of 180-350℃ and a temperature control accuracy of ±0.5℃. The detector temperature control unit is equipped with an insulation layer made of aluminum silicate cotton with a thickness of 20mm to reduce heat loss. It can achieve temperature control for the detector temperature control unit in the prior art.

[0030] Furthermore, the pressure control module includes two sets of EPC electronic pressure controllers 4, one set of which serves as a hydrogen pressure control unit and an air pressure control unit, and the other set of which serves as a nitrogen pressure control unit.

[0031] The EPC electronic pressure controller 4 includes a circuit board, a pressure sensor, an air inlet, an air outlet proportional valve, and an air resistance. Gas flows in through the air inlet, and the circuit board controls the proportional valve to reach the specified pressure, which is then output through the air outlet via the air resistance. The pressure sensor provides feedback on the real-time pressure.

[0032] The inlet of the hydrogen pressure control unit is connected to the outlet of the hydrogen generator 8 and the external hydrogen inlet 16 in the independent sample injection module 10. The outlet of the hydrogen pressure control unit is connected to the FID detector 11 to control the hydrogen supply. The inlet of the air pressure control unit is connected to the outlet of the air purification module 9 and the external air inlet 15 in the independent sample injection module 10. The outlet of the air pressure control unit is connected to the FID detector 11 to control the air supply. The inlet of the nitrogen pressure control unit is connected to the external nitrogen inlet 14 in the independent sample injection module 10. The outlet of the nitrogen pressure control unit is connected to a switching valve, which is a 14-way switching valve 13. The switching valve is connected to the dual-column chromatography separation module 12. The 14-way switching valve 13 is connected to a valve motor 5, which is used to control the 14-way switching valve 13 to switch.

[0033] Furthermore, the intelligent control module 7 includes a main control board, a control switch 1, a touch display screen 19, a data storage module, a communication interface, and a fault diagnosis unit. This intelligent control module 7 is a control system in the prior art, which will not be described in detail here. The main control board is electrically connected to the automatic sample injection module, the independent sample injection module 10, the gas dilution module, the hydrogen generator 8, the air purification module 9, the chromatographic separation module 12, the FID detector 11, the multi-zone temperature control module, the pressure control module, and the data storage module, respectively, and is used to control sample injection switching, dilution ratio, chromatographic separation, detection signal acquisition, and data processing. The fault diagnosis unit can monitor abnormalities in flow rate, temperature, and pressure, and trigger audible and visual alarms, which can be a fault diagnosis unit in the prior art.

[0034] Example 1: The analyzer's main body casing measures 450mm × 350mm × 250mm (length × width × height), is made of cold-rolled steel plate (with powder-coated surface), and has a built-in cooling fan. The 16-way selector valve of the automatic sample injection module is model VICI EH16W, ​​with 16 injection ports; Intake module: MFC flow meter 1 with a range of 0-3000 mL / min, MFC flow meter 2 with a range of 0-100 mL / min, mixing chamber volume of 10 mL; Gas source module: hydrogen generator (PEM technology, hydrogen production 50mL / min, purity 99.999%), air purification device (0.1μm particulate filter + activated carbon filter + 13X molecular sieve). Chromatographic separation module: Methane column (2.5m×4mm, GDX-502 support), total hydrocarbon column (1.5m×3mm, stainless steel inert tube); FID detector: detection limit 0.05mg / m³, response time ≤1s; control unit: 10.1-inch touchscreen, supports USB data export; Temperature control module: The temperature control range of the column temperature control chamber is 30-200℃ (accuracy ±0.1℃), and the temperature control of the FID detector is 300℃ (accuracy ±0.5℃).

[0035] When the instrument is powered on, connect a 220V AC power supply, connect nitrogen to the external nitrogen inlet 14, and inject pure water into the hydrogen generator 8 until the water level exceeds the minimum mark. Turn on the instrument switch. After the main control board is powered on, it automatically controls the sixteen-way selector valve 3 to return to its original position, the air pump automatically starts working, and provides air to the instrument through the air purification device. The hydrogen generator automatically starts working, providing hydrogen to the instrument. The main control board controls the electronic pressure controller to control the pressure and flow rate of air, hydrogen, and nitrogen. The main control board controls the chromatographic separation module, the fourteen-way switching valve 13, and the FID detector 9 to start heating to the set temperature. After the instrument temperature and pressure parameters are ready, the main control board issues an ignition command, providing high voltage to the FID detector for ignition. After successful ignition, the instrument enters the ready state and can be used for subsequent analysis.

[0036] Example 2: During sample injection (e.g.) Figure 6 Connect the gas collection bag containing the sample gas to the instrument's injection interface and open the gas collection bag valve. On the display screen, use the intelligent control module 7 to set the sample injection sequence for non-methane total hydrocarbons and start the analysis program. Set the sample name, sample location, dilution factor, number of injections, calibration curve, and other information. After the injection sequence information is sent, the instrument controls the temperature of each component according to the injection sequence information: switching valve temperature 120℃, FID detector temperature 300℃, and methane column and total hydrocarbon column temperatures 80℃. Once all instrument components reach their preset temperatures, the main control board issues a sample injection start command, the analysis program begins, the 16-port switching valve 3 switches to the predetermined position, and simultaneously the 1-port 3-way solenoid valve switches to the connection state between ports 1 and 3. At this time, the 14-port valve 13 is in the sample injection mode (OFF position), the sample pump operates, and the sample gas flows in through port 1 of the 14-port valve, enters the total hydrocarbon column quantitative loop 1 and the methane column quantitative loop 2 through port 14. The volume of both quantitative loops 1 and 2 is 1 mL. The remaining gas is discharged from the system through ports 3 and 2. The sample injection flow rate is 500 mL / min, and the injection time is 0.1 min.

[0037] After the injection stage is completed (e.g.) Figure 7The injection pump stops working, and the 14-way valve 13 switches to the analysis mode (ON position) driven by the motor. The electronic pressure controller EPC1 controls the nitrogen flow path 1 to enter the quantitative loop 1 from port 12 through port 13, purging the retained sample. The nitrogen inlet pressure of EPC1 is 0.4 MPa, and the outlet pressure is 7 psi. This gas flow then enters the total hydrocarbon analysis column (1.5 m × 3 mm, stainless steel inert tube) through ports 14 and 13 for separation, and finally enters the flame ionization detector (FID). At the same time, the nitrogen 3 flow path in EPC1 enters the quantitative loop 2 from port 9 through port 10, purging the remaining components, which then enter the methane analysis column (2.5 m × 4 mm, GDX-502 support) through ports 3 and 4 for separation, and also enters the FID detector. The hydrogen and air supply for the FID detector is controlled by an electronic pressure controller EPC2. The EPC2 air inlet pressure is 0.4 MPa, and the outlet air flow rate is 200 mL / min. The EPC2 hydrogen inlet pressure is 0.4 MPa, and the outlet hydrogen flow rate is 25 mL / min. The two gases mix in the FID chamber, and a high-voltage signal generated by the circuit board ignites the detector via the ignition coil. Upon successful ignition, the high-voltage signal shuts off, and the FID detector remains in combustion mode. Under normal ignition conditions, the baseline value of the FID detector's electrical signal is approximately 10 pA. A backflush process is set during the analysis, with a time limit of 1 minute. When the analysis time reaches the backflush start time, the fourteen-way valve 13 switches to the sample injection mode (OFF position) driven by the motor. Figure 6 The injection pump starts working, purging the total hydrocarbon column quantitative loop 1 and the methane column quantitative loop 2 at a flow rate of 500 mL / min, removing impurities that failed to enter the column with the carrier gas. Simultaneously, the nitrogen flow path 3 of the electronic pressure controller EPC1 backflushes the methane column, blowing out large molecules that move slowly within the methane column in the opposite direction. These molecules are then directly discharged from the analysis system through vent port 5 to prevent interference with subsequent measurements. The backflush pressure is 7 psi. The entire analysis process takes 2 minutes. The electrical signal generated by the FID is transmitted to the system main control board and converted into a corresponding chromatogram by the host computer software. After the analysis, the injection pump stops working, the backflush process stops, the host computer software processes the chromatogram data, and the results are stored in the instrument's built-in database and displayed on the screen.

[0038] After the above single analysis process is completed, the information for the next sample in the injection sequence is read, and the above steps are repeated until the entire injection sequence analysis is completed. After the injection sequence analysis is completed, the instrument returns to the ready state, and the user can perform operations such as method editing, sample data viewing, data processing, printing, and creating new sequences through the display screen.

[0039] Example 3: When performing sample dilution injection (e.g.) Figure 8The user connects the gas collection bag containing the sample gas to the sample dilution injection interface on the back of the instrument and opens the gas collection bag valve. On the display screen, the user sets the sample dilution sequence for non-methane total hydrocarbons, including sample name, sample location, dilution factor, injection count, calibration curve, and other information. After the injection sequence information is sent, the instrument controls the temperature of each component according to the injection sequence information: switching valve temperature 120℃, FID detector temperature 300℃, and methane and total hydrocarbon column temperatures 80℃. Once all instrument components reach the preset temperature, the system main control board first calculates and allocates the corresponding flow rates of mass flow controllers MFC1 and MFC2 based on the preset dilution factor. In this embodiment, the preset dilution factor is set to 10 times, and after calculation by the main control board, the preset flow rates of MFC1 and MFC2 are 100 and 900 mL / min, respectively. Subsequently, the second three-way solenoid valve switches to the connection state between interfaces 1 and 3. The sample gas is driven by a diaphragm pump and corresponding solenoid valves, with the flow rate precisely controlled by MFC1 and introduced into the mixing tank. Simultaneously, high-purity nitrogen is synchronously introduced into the mixing tank by MFC2. Afterwards, the No. 1 three-way solenoid valve switches to the connection state between interfaces 2 and 3, allowing the diluted mixed gas to enter the fourteen-way valve 13. When the flow rates of MFC1 and MFC2 reach the preset flow rates, the instrument main control board issues an injection start command, and the analysis program starts. At this time, the fourteen-way valve 13 is in injection mode (OFF position), the injection pump operates, and the sample gas flows in through port 1 of the fourteen-way valve, enters the total hydrocarbon column quantitative loop 1 and the methane column quantitative loop 2 through port 14, with each quantitative loop having a volume of 1 mL. The remaining gas is discharged from the system through ports 3 and 2. The injection flow rate is 500 mL / min, and the injection time is 0.1 min. After the injection stage, the injection pump and diaphragm pump stop operating, MFC1 and MFC2 close, and the No. 1 three-way solenoid valve switches to the connection state between interfaces 1 and 3. The 14-way valve 13 is switched to analysis mode (ON position) by the motor. Figure 7The electronic pressure controller EPC1 controls the nitrogen flow path 1 to enter the quantitative loop 1 through port 12 and port 13, purging the retained sample. The nitrogen inlet pressure of EPC1 is 0.4 MPa, and the outlet pressure is 7 psi. This gas flow then enters the total hydrocarbon analysis column (1.5 m × 3 mm, stainless steel inert tube) through ports 14 and 13 for separation, and finally enters the flame ionization detector (FID). Simultaneously, nitrogen flow path 3 in EPC1 enters the quantitative loop 2 through port 9 and port 10, purging the remaining components, which then enter the methane analysis column (2.5 m × 4 mm, GDX-502 support) through ports 3 and 4 for separation, and also enters the FID detector. The hydrogen and air supply for the FID detector is controlled by an electronic pressure controller EPC2. The EPC2 air inlet pressure is 0.4 MPa, and the outlet air flow rate is 200 mL / min. The EPC2 hydrogen inlet pressure is 0.4 MPa, and the outlet hydrogen flow rate is 25 mL / min. The two gases mix in the FID chamber, and a high-voltage signal generated by the circuit board ignites the detector via the ignition coil. Upon successful ignition, the high-voltage signal shuts off, and the FID detector remains in combustion mode. Under normal ignition conditions, the baseline value of the FID detector's electrical signal is approximately 10 pA. A backflush process is set during the analysis, with a time limit of 1 minute. When the analysis time reaches the backflush start time, the fourteen-way valve 13 switches to the sample injection mode (OFF position) driven by the motor. Figure 6 The injection pump starts working, purging the total hydrocarbon column quantitative loop 1 and the methane column quantitative loop 2 at a flow rate of 500 mL / min, removing impurities that failed to enter the column with the carrier gas. Simultaneously, the nitrogen flow path 3 of the electronic pressure controller EPC1 backflushes the methane column, blowing out large molecules that move slowly within the methane column in the opposite direction. These molecules are then directly discharged from the analysis system through vent port 5 to prevent interference with subsequent measurements. The backflush pressure is 7 psi. The entire analysis process takes 2 minutes. The electrical signal generated by the FID is transmitted to the system main control board and converted into a corresponding chromatogram by the host computer software. After the analysis, the injection pump stops working, the backflush process stops, the host computer software processes the chromatogram data, and the results are stored in the instrument's built-in database and displayed on the screen.

[0040] After the above single analysis process is completed, the information for the next sample in the injection sequence is read, and the above steps are repeated until the entire injection sequence analysis is completed. After the injection sequence analysis is completed, the instrument returns to the ready state, and the user can perform operations such as method editing, sample data viewing, data processing, printing, and creating new sequences through the display screen.

[0041] Example 4: When performing standard gas injection (such as...) Figure 9The user connects the standard gas cylinder to the standard gas injection port on the back of the instrument via a pressure reducing valve and tubing, and opens the pressure reducing valve to control the standard gas pressure at approximately 0.2 MPa. The user then sets the standard gas injection sequence for non-methane total hydrocarbons on the display screen, specifying the sample name, sample location, dilution factor, number of injections, calibration curve, and other information. After the injection sequence information is sent, the instrument controls the temperature of each component according to the injection sequence information: the switching valve temperature is 120℃, the FID detector temperature is 300℃, and the methane and total hydrocarbon column temperatures are 80℃. Once all instrument components reach the preset temperature, the system main control board first calculates and allocates the corresponding flow rates of mass flow controllers MFC1 and MFC2 based on the preset dilution factor. In this embodiment, the preset dilution factor is set to 10 times, and after calculation by the main control board, the preset flow rates of MFC1 and MFC2 are 100 mL / min and 900 mL / min, respectively. Subsequently, the No. 2 three-way solenoid valve is switched to the state where interfaces 2 and 3 are connected, and the standard gas flow is precisely controlled by MFC1 and introduced into the mixing tank; simultaneously, high-purity nitrogen gas is controlled by MFC2 and synchronously flows into the mixing tank. Afterwards, the No. 1 three-way solenoid valve is switched to the state where interfaces 2 and 3 are connected, allowing the diluted mixed gas to enter the fourteen-way valve 13. When the flow rates of MFC1 and MFC2 reach the preset flow rates, the instrument main control board issues an injection start command, and the analysis program starts. At this time, the fourteen-way valve 13 is in injection mode (OFF position), the injection pump operates, and the sample gas flows in through port 1 of the fourteen-way valve, enters the total hydrocarbon column quantitative loop 1 and the methane column quantitative loop 2 through port 14, with each quantitative loop having a volume of 1 mL. The remaining gas is discharged from the system through ports 3 and 2. The injection flow rate is 500 mL / min, and the injection time is 0.1 min. After the injection stage is completed, the injection pump stops working, MFC1 and MFC2 are closed, and the No. 1 three-way solenoid valve is switched to the state where interfaces 1 and 3 are connected. The 14-way valve 13 is switched to analysis mode (ON position) by the motor. Figure 7The electronic pressure controller EPC1 controls the nitrogen flow path 1 to enter the quantitative loop 1 through port 12 and port 13, purging the retained sample. The nitrogen inlet pressure of EPC1 is 0.4 MPa, and the outlet pressure is 7 psi. This gas flow then enters the total hydrocarbon analysis column (1.5 m × 3 mm, stainless steel inert tube) through ports 14 and 13 for separation, and finally enters the flame ionization detector (FID). Simultaneously, nitrogen flow path 3 in EPC1 enters the quantitative loop 2 through port 9 and port 10, purging the remaining components, which then enter the methane analysis column (2.5 m × 4 mm, GDX-502 support) through ports 3 and 4 for separation, and also enters the FID detector. The hydrogen and air supply for the FID detector is controlled by an electronic pressure controller EPC2. The EPC2 air inlet pressure is 0.4 MPa, and the outlet air flow rate is 200 mL / min. The EPC2 hydrogen inlet pressure is 0.4 MPa, and the outlet hydrogen flow rate is 25 mL / min. The two gases mix in the FID chamber, and a high-voltage signal generated by the circuit board ignites the detector via the ignition coil. Upon successful ignition, the high-voltage signal shuts off, and the FID detector remains in combustion mode. Under normal ignition conditions, the baseline value of the FID detector's electrical signal is approximately 10 pA. A backflush process is set during the analysis, with a time limit of 1 minute. When the analysis time reaches the backflush start time, the fourteen-way valve 13 switches to the sample injection mode (OFF position) driven by the motor. Figure 6 The injection pump starts working, purging the total hydrocarbon column quantitative loop 1 and the methane column quantitative loop 2 at a flow rate of 500 mL / min, removing impurities that failed to enter the column with the carrier gas. Simultaneously, the nitrogen flow path 3 of the electronic pressure controller EPC1 backflushes the methane column, blowing out large molecules that move slowly within the methane column in the opposite direction. These molecules are then directly discharged from the analysis system through vent port 5 to prevent interference with subsequent measurements. The backflush pressure is 7 psi. The entire analysis process takes 2 minutes. The electrical signal generated by the FID is transmitted to the system main control board and converted into a corresponding chromatogram by the host computer software. After the analysis, the injection pump stops working, the backflush process stops, the host computer software processes the chromatogram data, and the results are stored in the instrument's built-in database and displayed on the screen.

[0042] After the above single analysis process is completed, the information for the next sample in the injection sequence is read, and the above steps are repeated until the entire injection sequence analysis is completed. After the injection sequence analysis is completed, the instrument returns to the ready state, and the user can perform operations such as method editing, sample data viewing, data processing, printing, and creating new sequences through the display screen.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A benchtop non-methane total hydrocarbon analyzer, characterized in that, include: The analyzer body includes an automatic sample injection module, which includes multiple injection ports, a multi-way selector valve, an injection pump, and a quantitative loop. The multi-way selector valve and the injection ports are one-to-one and are used for automatic switching of multiple samples. The injection pump is used to extract samples from the rear end and enter the quantitative loop through the designated injection port. The quantitative loop includes a total hydrocarbon column quantitative loop and a methane column quantitative loop. The outlets are connected to the total hydrocarbon chromatographic column and the methane chromatographic column of the chromatographic separation module (12) through a switching valve (13), respectively. The independent sample introduction module (10) is equipped with multiple gas inlets for introducing gas for single detection, thereby realizing gas introduction. The intake dilution module is used to dilute the gas. A hydrogen generator (8) is used to generate high-purity hydrogen to provide an independent hydrogen source for the FID detector (11); An air purification module (9) is used to purify ambient air and provide an independent air source for the FID detector (11); The chromatographic separation module (12) includes a total hydrocarbon chromatographic column and a methane chromatographic column, which is a dual-column chromatographic separation module (12) used for the passage and separation of total hydrocarbon components from methane in the sample; FID detector (11), which is connected to the chromatographic separation module (12), generates a special electrical signal when the analyte passes through the FID detector, which is used for the qualitative and quantitative analysis of the compound; The multi-zone temperature control module includes a column oven, a switching valve temperature control unit, and a detector temperature control unit, used for temperature control; The pressure control module includes two sets of EPC electronic pressure controllers (4) for controlling the flow rates of hydrogen, air, and nitrogen. The inlet of one set of EPC electronic pressure controllers is connected to the hydrogen generator (8), air purification module (9), and independent sample injection module (10) through a gas pipeline, and the outlet is connected to the FID detector (11) through a gas pipeline. The inlet of the other set of EPC electronic pressure controllers is connected to the independent sample injection module (10) through a gas pipeline, and the outlet is connected to the switching valve (13). The intelligent control module (7) is electrically connected to the automatic sample injection module, the independent sample injection module (10), the gas dilution module, the hydrogen generator (8), the air purification module (9), the chromatographic separation module (12), the FID detector (11), the multi-zone temperature control module, and the pressure control module, respectively.

2. The benchtop non-methane total hydrocarbon analyzer according to claim 1, characterized in that: The injection port is set to a sixteen-position injection port (2), and the multi-port selection valve is set to a sixteen-port selection valve (3). The sixteen-port selection valve (3) corresponds one-to-one with the sixteen-position injection port (2) and is used for automatic switching injection of multiple groups of samples.

3. A benchtop non-methane total hydrocarbon analyzer according to claim 2, characterized in that: The independent sample injection module (10) includes an external nitrogen inlet (14), an external air inlet (15), an external hydrogen inlet (16), an external standard gas inlet (17), and a dilution sample inlet (18). The external nitrogen inlet (14), the external air inlet (15), the external hydrogen inlet (16), the external standard gas inlet (17), and the dilution sample inlet (18) are sequentially arranged on the outside of the analyzer body.

4. A benchtop non-methane total hydrocarbon analyzer according to claim 3, characterized in that: The gas dilution module includes a mixing chamber, a dilution gas inlet, a sampling pump, and a mass flow controller. The mass flow controller is configured in two sets. The mass flow controller is an MFC flow meter (6). The inlet and outlet of one set of the mass flow controller are connected to the external nitrogen inlet (14) and the mixing chamber, respectively. The inlet of the other set of the mass flow controller is connected to a three-way selector valve. The other two ends of the three-way selector valve are connected to the sampling pump and the external standard gas inlet (17), respectively. The sampling pump is connected to the dilution sample inlet (18). The outlet of the other set of the mass flow controller is connected to the mixing chamber.

5. A benchtop non-methane total hydrocarbon analyzer according to claim 4, characterized in that: The hydrogen generator (8) is configured as a proton exchange membrane electrolysis water type; The air purification module (9) includes an air pump and an air purification device, wherein the air purification device includes a high-temperature hydrocarbon removal unit, a silica gel dehydration unit, and a molecular sieve impurity removal unit connected in series.

6. A benchtop non-methane total hydrocarbon analyzer according to claim 5, characterized in that: The total hydrocarbon chromatographic column is a silanized stainless steel empty column, used for the non-retention passage of total hydrocarbon components; The methane-specific chromatographic column is an inert stainless steel packed column, used for the specific separation of methane in samples; The outlet of the mixing chamber of the gas dilution module is connected to an injection loop via a three-way valve and a switching valve (13). The injection loop is connected to the inlet of the methane column and the total hydrocarbon column via the switching valve (13). The outlets of the methane column and the total hydrocarbon column are both connected to the FID detector (11) via the switching valve (13).

7. A benchtop non-methane total hydrocarbon analyzer according to claim 6, characterized in that: The FID detector (11) includes a combustion chamber, an ignition assembly, an ion collecting electrode and a signal processing unit. The hydrogen inlet and air inlet of the FID detector (11) are respectively connected to the hydrogen and air outlets of a set of EPC electronic pressure controllers (4).

8. A benchtop non-methane total hydrocarbon analyzer according to claim 7, characterized in that: The column oven is equipped with two independent temperature control zones, which correspond one-to-one with the total hydrocarbon column and the methane column, respectively. The switching valve temperature control unit is used to control the temperature of the switching valve (13); The detector temperature control unit encloses the combustion chamber of the FID detector (11), and the detector temperature control unit is provided with a heat insulation layer.

9. A benchtop non-methane total hydrocarbon analyzer according to claim 8, characterized in that: The pressure control module includes two sets of EPC electronic pressure controllers (4), one set of which serves as a hydrogen pressure control unit and an air pressure control unit, and the other set of which serves as a nitrogen pressure control unit. The EPC electronic pressure controller (4) includes a circuit board, a pressure sensor, an air inlet, an air outlet proportional valve, and an air resistance. Gas flows in through the air inlet, and the circuit board controls the proportional valve to reach the specified pressure and outputs it through the air outlet via the air resistance. The pressure sensor provides feedback on the real-time pressure. The inlet of the hydrogen pressure control unit is connected to the outlet of the hydrogen generator (8) and the external hydrogen inlet (16) in the independent sample injection module (10). The outlet of the hydrogen pressure control unit is connected to the FID detector (11) to control the hydrogen supply. The inlet of the air pressure control unit is connected to the outlet of the air purification module (9) and the external air inlet (15) in the independent sample injection module (10). The outlet of the air pressure control unit is connected to the FID detector (11) to control the air supply. The inlet of the nitrogen pressure control unit is connected to the external nitrogen inlet (14) in the independent sample injection module (10). The outlet of the nitrogen pressure control unit is connected to a switching valve, which is a fourteen-way switching valve (13). The switching valve is connected to the dual-column chromatography separation module (12). The fourteen-way switching valve (13) is connected to a valve motor (5), which is used to control the fourteen-way switching valve (13) to switch.

10. A benchtop non-methane total hydrocarbon analyzer according to claim 9, characterized in that: The intelligent control module (7) includes a main control board, a control switch (1), a touch screen (19), a data storage module, a communication interface, and a fault diagnosis unit. The main control board is electrically connected to the automatic sample injection module, the independent sample injection module (10), the gas dilution module, the hydrogen generator (8), the air purification module (9), the chromatographic separation module (12), the FID detector (11), the multi-zone temperature control module, the pressure control module, and the data storage module.

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