CN115684080A - VOCs concentration online monitoring system and method for oil gas recovery system of finished oil depot - Google Patents
VOCs concentration online monitoring system and method for oil gas recovery system of finished oil depot Download PDFInfo
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Abstract
The invention particularly relates to a VOCs concentration online monitoring system and method for a product oil depot oil gas recovery system. The monitoring system comprises a control system and field detection equipment, wherein light generated by a light source generating device enters the field detection equipment through optical fibers, emergent light of the field detection equipment enters a photoelectric detector through the optical fibers, and the photoelectric detector is connected with a data acquisition card. The light source generating device and the data acquisition card are both connected with the computer. The on-site detection equipment comprises a gas pool, a laser collimating mirror, a temperature sensor and a gas pressure sensor, wherein the gas pool is divided into a detection gas pool and a reference gas pool, an incident light port and an emergent light port are formed below the gas pool, and a reflector is arranged on the inner side above the gas pool; the laser collimating lens is arranged at the position of the incident light port and the emergent light port, the laser collimating lens is connected with the optical fiber, and the temperature sensor and the air pressure sensor are connected with the data acquisition card. The invention can monitor the oil gas concentration of the discharge port and the easy leakage point of the oil gas recovery system of the finished oil depot in real time.
Description
Technical Field
The invention relates to the field of detection of concentration of VOCs (volatile organic compounds) of an oil gas recovery system of a finished oil depot, and particularly provides a multi-azimuth reflective online detection method for detecting concentration of VOCs at a discharge port and a leakage point of the oil gas recovery system of the finished oil depot.
Background
Because the volatility of the gasoline causes the gasoline to release a large amount of oil gas in the processes of storage, transportation and sale, and the environmental air is polluted. The oil gas contains a large amount of hydrocarbon organic compounds with boiling points below 120 ℃, such as alkane, alkene, benzene series and the like, wherein the alkane is taken as the main component and accounts for about 50 percent. Many carcinogenic and teratogenic substances exist in hydrocarbon VOCs, and have great harm to human bodies and surrounding environments. Meanwhile, the hydrocarbon VOCs are key precursor substances in the troposphere and have the characteristics of strong activity, volatility and the like. Under appropriate conditions, a photochemical reaction occurs. The hydrocarbon VOCs combine with nitrogen oxides, halogenated hydrocarbons and other organic pollutants in the atmosphere to generate ozone (O) 3 ) Fine Particulate Matter (PM) 2.5 ) And Secondary Organic Aerosols (SOA), leading to urban haze and photochemical pollution.
The oil gas pollution problem is solved, and the environmental pollution problem caused by oil gas is reduced. At present, oil gas recovery systems are additionally arranged in oil depots of China in operation to recover and treat volatile oil gas in the processes of storage, loading, unloading and sale so as to reduce the influence on the environment. Therefore, the real-time detection of the concentrations of the hydrocarbon VOCs at the discharge port and the easy leakage point of the oil gas recovery system is an important measure for effectively monitoring and preventing the environmental pollution.
Disclosure of Invention
Because volatile oil gas VOCs has stronger extinction ability, consequently, can utilize optical technology to carry out real-time supervision to the oil gas concentration of oil gas recovery system discharge port and easy leak point. The invention provides a monitoring system and a monitoring method for monitoring VOCs concentration of a discharge port and an easy leakage point of an oil gas recovery system of a finished oil depot in real time.
The invention specifically adopts the following technical scheme:
a VOCs concentration online monitoring system of a product oil depot oil gas recovery system comprises a control system and field detection equipment.
The control system comprises a light source generating device, a photoelectric detector, a data acquisition card and a computer, wherein light generated by the light source generating device enters the field detection equipment through optical fiber reflection, emergent light enters the input end of the photoelectric detector through optical fiber, and the output end of the photoelectric detector is connected with the data acquisition card. The light source generating device and the data acquisition card are both connected with the computer.
The on-site detection equipment comprises a gas pool, a laser collimating mirror, a temperature sensor and a gas pressure sensor, wherein the gas pool is divided into a detection gas pool and a reference gas pool, the detection gas pool is arranged at a discharge port and an easy leakage point of the oil gas recovery system, and the reference gas pool is arranged at a safe area. The gas tank is provided with gas holes around the gas tank, an incident light port and an emergent light port are arranged below the gas tank, and a reflector is arranged on the inner side above the gas tank; the laser collimating lens is arranged at the position of the incident light port and the emergent light port and connected with the optical fiber, so that light generated by the light source generating device enters the gas pool through the optical fiber after passing through the laser collimating lens, and light coming out of the gas pool enters the photoelectric detector through the optical fiber after passing through the laser collimating lens. And the temperature sensor and the air pressure sensor are both connected with the data acquisition card. The data acquisition card comprises a photoelectric data acquisition card, a temperature data acquisition card and an air pressure data acquisition card, and the photoelectric detector, the temperature sensor and the air pressure sensor are respectively connected with the photoelectric data acquisition card, the temperature data acquisition card and the air pressure data acquisition card.
In a further preferred scheme, the light source generating device comprises a laser controller, a semiconductor laser and an optical fiber coupler which are sequentially connected, and the optical fiber coupler is connected with the field detection equipment through an optical fiber; the laser controller is also connected with a computer.
In a further preferred embodiment, the semiconductor laser is a DFB tunable semiconductor laser that produces a signal characterized by a center wavenumber of 3081cm -1 With a period of 1s at 1cm -1 Sawtooth-shaped sweep-frequency light within the range. The fiber coupler is a 1 × 2 single-mode fiber coupler, the two ends of the fiber coupler are connected by FC flanges, and the splitting ratio is 50. The optical fiber is an aluminum trifluoride glass optical fiber, and can effectively reduce the loss in transmitting mid-infrared band light.
In a further preferred scheme, the gas pool is an aluminum metal cuboid, and a reflector bracket is arranged on the inner side above the gas pool and used for supporting a reflector.
The reflector is metal film plated glass; the laser collimating lens is an aspheric lens with an FC flange interface at the tail and an AR coating at the head.
The photoelectric detector adopts indium arsenic antimony material, can detect the light of 2000nm ~ 5000nm wave band. The photoelectric signal, temperature and air pressure data acquisition card adopts C8051F120, has the functions of data acquisition, A/D conversion, signal transmission and the like, and can meet the basic requirements of data processing of the invention.
A VOCs concentration online monitoring method for a product oil depot oil gas recovery system comprises the following steps:
(1) And (3) determining the easy leakage points of the oil gas recovery system of the finished oil depot through detection data analysis, and setting the on-site detection equipment aiming at the easy leakage points and the discharge port of the oil gas recovery system. Specifically, the PVC air bag is adopted to collect gas at each easy leakage point of a finished oil depot oil gas recovery system, and then the gas is analyzed by a gas chromatograph to finally determine the point position of on-site detection equipment.
(2) The central wave number emitted by the semiconductor laser is 3081cm -1 The period is 1s and is 1cm -1 The sawtooth frequency-sweeping light in the range is coupled into the optical fiber and then divided into two paths by the optical fiber coupler.
(3) Light passes through the laser collimating lens along the optical fiber, enters the detection gas pool on one way, enters the reference gas pool on the other way, and gas (ambient air around the monitored point) freely flows through the gas holes in the gas pool body.
(4) The light enters the gas tank, is reflected by the reflector, is coupled into the optical fiber again by the laser collimating mirror and is transmitted to the photoelectric detector.
(5) The data acquisition card acquires data output by the photoelectric detector, the temperature sensor and the air pressure sensor.
(6) And after the data acquisition card transmits the data to the computer, the concentration of VOCs at the monitored point of the oil gas recovery system is calculated, and a user can realize online monitoring of the concentration of VOCs at the discharge port and the easy leakage point of the oil gas recovery system of the finished oil depot through a human-computer interaction interface. The man-machine interaction interface adopts Qt programming and has the functions of data operation, real-time checking of detection data, historical data backtracking and standard exceeding data checking.
In the step (6), the concentration of VOCs at the monitored point of the oil gas recovery system is calculated by adopting the following formula:
wherein, c General assembly The concentration value of VOCs at the monitored point of the oil gas recovery system is represented, and the concentration value of olefin at the monitored point of the oil gas recovery system is represented by c; h 0 Represents a direct current component; s (T) represents the gas absorption line intensity; t represents the real-time temperature near the oil gas recovery system of the reservoir area; l is a detection effective optical path; Δ v c Representing full width at half maximum.
The beneficial effects of the invention are as follows:
1. the detection real-time performance is strong: compared with other detection methods and detection means, the detection system designed by the invention can be deployed on line, and can be used for monitoring the concentration of VOCs at the discharge port and the easy leakage point of the oil gas recovery system of the finished oil depot in real time;
2. the safety risk is extremely low: according to the detection principle and the system structure, only optical devices exist in a detection field, the insulation performance is good, and the safety risk is extremely low compared with other detection methods in a flammable and explosive environment of a finished oil depot;
3. the detection probe is miniaturized: compared with the large concentration monitoring instrument arranged on site at present, the small detection probe designed by the invention can be arranged at the discharge port and the easy leakage point of the oil gas recovery system of the finished oil depot for accurate detection;
4. optical fiber transmission detection light: the detection probe is connected through an optical fiber, and the light source and the optical signal processing system can be arranged in a control room of the finished oil depot;
5. the reflective structure: by adopting the optical reflection principle, compared with a transmission type, the volume of the detection device can be reduced, so that the detection mode is more convenient, the detection part is more accurate, and the detection scene is wider;
6. the detection accuracy is high: the method adopts a double-light path design, one is a detection light path, the other is a reference light path, the reference light path is placed in a safe area, zero gas is introduced into a gas pool, and the acquired optical signal of the reference light path can effectively avoid the measurement error caused by a fitting baseline method. And meanwhile, an absorption spectrum line correction algorithm is introduced, so that the detection precision is improved.
7. The detection is highly representative: the oil gas recovery system of the oil depot is detected and analyzed in detail to obtain the easy leakage points of the oil gas recovery system, so that the arrangement of the detection system is more targeted;
8. the measurement result is reliable, and is suitable for extensively: the invention can also be used for monitoring the leakage concentration of the oil gas recovery system in other oil storage and oil selling environments such as a gas station and the like.
Drawings
Fig. 1 is a structure diagram of a product oil depot oil gas recovery system.
FIG. 2 is a flow chart of an online monitoring system for VOCs at a point of easy leakage of a product oil depot oil gas recovery system.
FIG. 3 is a first internal structure diagram of a detection gas pool of a discharge port of a product oil depot oil gas recovery system and an easy-leakage point VOCs online monitoring system.
Fig. 4 is a second structure diagram of the internal structure of the gas pool for detecting the oil gas recovery system discharge port of the finished oil depot and the easy-leakage point VOCs on-line monitoring system.
In the attached fig. 3 and 4, 1 is a gas cell body, 2 is a gas hole, 3 is a reflector, 4 is an incident light port, 5 is an emergent light port, 6 is a laser collimator, 7 is an FC flange interface, and 8 is an optical fiber.
Detailed Description
The present invention will be described in more detail with reference to the following embodiments for understanding the technical solutions of the present invention, but the present invention is not limited to the scope of the present invention.
Example 1
In the embodiment, the online monitoring system and method for the concentration of VOCs (volatile organic compounds) at the discharge port and the easy-leakage point of the oil-gas recovery system of the reflective finished oil depot are specifically described from the aspects of detection point selection, measurement principle and system structure.
1. Detection point selection
The oil gas recovery system of the finished oil depot mainly adopts an activated carbon adsorption method to adsorb oil gas generated by an oil depot tank field and loading and unloading facilities so as to reduce the pollution to the environment.
The specific structure of the oil gas recovery system of the finished oil depot is shown in figure 1, and the oil gas recovery system comprises three parts which are respectively as follows: an adsorption unit, a vacuum regeneration (desorption) unit and an oil gas absorption unit. The adsorption unit absorbs the light hydrocarbon components in the oil gas by utilizing the different affinity of the activated carbon and the air and the light hydrocarbon components in the oil gas, thereby realizing the separation of the light hydrocarbon and the air; the desorption unit adopts a vacuum pump to pump out the oil gas adsorbed by the activated carbon, so that the activated carbon recovers the adsorption function, the oil gas can be adsorbed again, and then the high-concentration oil gas is conveyed into the absorption tower; the absorption unit sprays and absorbs the oil gas subjected to desorption treatment in the absorption tower by using the liquid gasoline in the oil storage tank, so that the oil gas is converted into the liquid gasoline and then is input into the oil storage tank.
In order to analyze the position of the easy-to-leak point and effectively monitor the concentration of the discharge port, the oil gas discharge port and each easy-to-leak point in the first half of 2022 years of a certain finished product oil depot are detected, and the detection results are shown in tables 1 and 2.
TABLE 1 oil gas concentration detection data list of oil gas recovery system discharge port in the first half 2022 year of a certain product oil depot
TABLE 2 oil gas mass fraction detection data of oil gas recovery system of a certain product oil depot under different conditions of easy leakage sealing points
As can also be seen from tables 1 and 2, the locations to be monitored in the oil recovery system of the product oil depot include: oil gas discharge port, vacuum pump rotary seal, fuel feed pump rotary seal and scavenge pump rotary seal.
The working principle of the oil gas recovery system of the finished oil depot can be obtained, the oil gas concentration monitoring firstly needs to meet the detection of an oil gas discharge port, and the discharge concentration is monitored in real time, so that the condition that the finished oil depot does not exceed standard and discharge to pollute the environment is ensured; secondly, the vacuum pump, the oil supply pump and the oil return pump are rotating equipment, and when the oil gas recovery system works normally, oil gas (liquid) is easy to leak from a rotating sealing part, so that the quality fraction of the leakage exceeds the standard; the vibration generated during the operation of the pump can cause the connecting flanges of the inlet pipeline and the outlet pipeline of the pump to generate vibration, so that fastening bolts are loosened, and the leakage mass fraction exceeds the standard; when the oil tank truck loads oil at the oil loading position of a finished oil depot, the leakage mass fraction at the oil-gas connecting port exceeds the standard because an operator does not clamp the connecting port or damage the sealing gasket in the connecting port.
2. Principle of measurement
Since gasoline has strong volatility, the composition of gasoline leaking from the exhaust port and the easy leakage point is substantially identical to the light component of gasoline. The data in table 3 can be obtained by examining the gasoline component of a certain gasoline pool, and from the data in table 3, it can be seen that the content of olefin in gasoline is about 15%.
TABLE 3 detection data of gasoline component in certain product oil depot
| Number of times | Detecting items | Quality index | The result of the detection |
| 1 | Olefin content (volume fraction)/% | ≤19 | 14.1 |
| 2 | Olefin content (volume fraction)/%) | ≤19 | 15.8 |
| 3 | Olefin content (volume fraction)/%) | ≤19 | 16.0 |
| 4 | Olefin content (volume fraction)/%) | ≤19 | 14.7 |
The query shows that the-CH = CH of olefin in gasoline 2 The basic vibration of the infrared extension of the group occurs at 3081cm -1 Therefore, the center wave number of 3081cm is selected in the present invention -1 The light source is used for monitoring the oil gas concentration of the discharge port and the easy leakage point of the oil gas recovery system in real time.
The detection principle is as follows:
since gasoline has strong volatility, the composition of gasoline leaking from the exhaust port and the easy leakage point is substantially identical to the light component of gasoline. When light with specific frequency is emitted into oil gas to be detected, the transmitted light intensity is weakened due to the absorption of light inside the molecules of the substance to be detected. The incident light intensity and the transmitted light intensity satisfy the following conditions:
I(v)＝I 0 (v) exp (-S (T) phi (v) PcL), formula (1);
in the formula (1), L is effective optical path for detection and has a unit of [ cm [)](ii) a P is ambient air pressure in atm](ii) a c is olefin concentration of monitored point of oil gas recovery system, and volume fraction (unit is [ ppm)]) Characterizing; v is the frequency of the probe light in cm -1 ]；I 0 (v) Is the intensity of the incident light; i (v) is the intensity of transmitted light. Phi (v) is a gas absorption linear function, and since the VOCs concentration online monitoring system of the oil gas recovery system of the finished oil depot operates at normal temperature, the pressure in the gas pool has great influence on the gas concentration, and the spontaneous radiation and uniform broadening caused by collision with other particles are dominant, the gas absorption linear function is described by adopting a Lorentz linear form, and the unit is [ cm ] (cm)]。
In the formula (2), v is the probe light frequency in [ cm ] -1 ]；v 0 For detecting the center frequency of light, in units of [ cm ] -1 ]；Δv c Represents a half-height width in [ cm ] -1 ]，Δν c Represented by the following formula (3):
in the formula (3), gamma is a gas pressure broadening coefficient, and gamma =0.087, T represents the real-time temperature near the oil and gas recovery system of the reservoir area; t is 0 =296k and p is ambient pressure.
S (T) in the formula (1) represents the gas absorption line intensity in [ atm [ ] -1 cm -2 ]Represented by the following formula (4):
S(T 0 ) Is at T 0 The line intensity of an absorption spectrum line at the temperature of =296K, T can be brought in by the real-time temperature near a reservoir oil and gas recovery system, T 0 =296K, h is the Planck constant, c 0 Is the speed of light in vacuum, E is the energy of the ground level, k is the Boltzmann constant, v 0 For the absorption line center frequency, Q (T) is the absorption line partition function at T temperature, Q (T) 0 ) Is T 0 The expression of the distribution function of the absorption line at the temperature is shown in the formula (5):
in the formula (5), E i Is the energy of the i-th energy level, g i I degree of degeneracy of the i-th level, h is Planck constant, c 0 The speed of light in vacuum, k is the Boltzmann constant, and T is the real-time temperature near the reservoir oil and gas recovery system.
For a two-level system structure, the ground level energy is E 1 ＝184.62cm -1 Excited state energy level of E 2 ＝hv+E 1 Degeneracy of ground state energy level of g 1 =14, excited state level degeneracy g 2 =13. Thus, the absorption line partition function is expressed by equation (6):
and (3) obtaining the concentration of the gas to be measured by inversion of the following formula (7):
performing Fourier series expansion on the formula:
in the formula (8), H n For Fourier series of n ordersThe number t is the time variable of the detection light;
extracting a direct current component:
in the formula (9), H 0 Indicating the dc component, dt represents the differential to t, t is the time variable of the probe light.
In the [0,1 ]]In the interior of said container body,
so that:
thus, the concentration of
D.c. component H 0 In a linear relationship with each other, and is,
the oil gas concentration can be finally calculated by the analysis data of the gasoline components as follows:
wherein, c General (1) And C represents the olefin concentration of the monitored point of the oil gas recovery system.
In general, the light source generating device emits a central wave number of 3081cm into the detection gas cell -1 The period is 1s and is 1cm -1 Sawtooth-shaped sweep-frequency light within the range. When the incident light passes through the gas pool containing the VOCs gas, the incident light is absorbed by olefin in the gas pool,thereby causing a change in light intensity. The content of olefin in the VOCs gas can be indirectly obtained by measuring the intensity of the reflected light through a photoelectric detector, and finally the total content of the VOCs gas is obtained by removing the olefin proportion.
3. On-line monitoring system structure
According to the measurement principle of the concentration of VOCs at the discharge port and the easy leakage point of the oil gas recovery system of the reflective finished oil depot, the VOCs concentration online monitoring system of the oil gas recovery system of the finished oil depot is set up, as shown in FIG. 2, the monitoring system comprises a control room and field detection equipment, and a laser controller, a DFB tunable semiconductor laser, a 1. The laser controller is connected with the DFB tunable semiconductor laser, the DFB tunable semiconductor laser is connected with the 1. The data acquisition card comprises a photoelectric data acquisition card, a temperature data acquisition card and an air pressure data acquisition card, wherein the photoelectric detector, the temperature sensor and the air pressure sensor are respectively connected with the photoelectric data acquisition card, the temperature data acquisition card and the air pressure data acquisition card.
As shown in fig. 3 and 4, oil gas recovery system includes the gas pond, the gas pond divide into and detects the gas pond and consult the gas pond, and the gas pond includes that the gas pond body 1 of gas pocket is opened to the whole body, and gas pond body 1 is aluminium metal cuboid, and the gas pocket 2 is opened to the whole body, and open 1 below of gas pond body has incident light mouth 4 and emergent light mouth 5, and there is speculum 3 inside the gas pond body 1 top. The incident light port 4 and the emergent light port 5 are provided with a laser collimating mirror 6, and the laser collimating mirror 6 is connected with an optical fiber 8 through an FC flange interface 7.
And controlling the sawtooth frequency sweeping light of the DFB tunable semiconductor laser by a laser controller in a control room. The detection light emitted by the light source is coupled into an optical fiber and then is divided into two paths by a 1. The detection light enters the inlet of the gas tank body along the optical fiber, and the optical fiber light enters the aluminum metal gas tank after being expanded and collimated by the laser collimating lens. The side surface of the aluminum metal gas pool is provided with a plurality of air holes for free flow of gas. The detection light enters the gas cell body, is reflected by the two reflectors and then passes through the laser collimating mirror, and then is re-coupled into the optical fiber, the optical fiber transmits the light to the photoelectric detector in the control room, the output end of the photoelectric detector is connected with the input end of the photoelectric data acquisition card, and the photoelectric data acquisition card transmits the data to the computer through A/D conversion. Meanwhile, because the change of the discharge port and the easy leakage point of the oil gas recovery system of the finished oil depot and the change of the air pressure and the temperature of the safe region are extremely small, the environmental data collected by the temperature sensor and the air pressure sensor arranged in the safe region are respectively transmitted to the temperature data acquisition card and the air pressure data acquisition card and then transmitted to the computer, and the real-time concentration values of the VOCs of the discharge port and the easy leakage point of the oil gas recovery system of the finished oil depot can be calculated. A block flow diagram of the monitoring system is shown in fig. 2.
The light source of the oil gas recovery system is from a DFB tunable semiconductor laser, and the central wave number of the light source light is 3081cm -1 The period is 1s and is 1cm -1 Sawtooth-shaped frequency-sweeping light within a range; the optical fiber is an aluminum trifluoride-based glass optical fiber, so that the loss in transmitting intermediate infrared band light can be effectively reduced; the laser collimating lens is an FC flange interface at the tail part and an AR film-coated aspheric lens at the head part; the reflector is metal film plated glass; 1, the single-mode fiber coupler is an optical fiber coupler with FC flange interfaces at two ends and a splitting ratio of 50; the photoelectric detector is made of indium, arsenic and antimony and can detect light with a wave band of 2000 nm-5000 nm. The data acquisition card adopts C8051F120, has the functions of data acquisition, A/D conversion, signal transmission and the like, and can meet the basic requirement on data processing of the invention; the man-machine interaction interface adopts Qt programming and has the functions of data operation, real-time checking of detection data, backtracking of historical data and checking of over-standard data.
Detecting and analyzing data of the easy-leakage point, collecting the easy-leakage point gas of the oil gas recovery system of the finished oil depot by adopting a PVC (polyvinyl chloride) air bag, and then sending the easy-leakage point gas to a laboratory for analysis by a gas chromatograph to finally determine the easy-leakage point to be detected; the system analyzes the components of the gasoline in the finished product oil depot through a laboratory, and confirms that the proportion of the olefin in the gasoline is about 15 percent.
The above-described embodiments are merely preferred embodiments of the present invention, and not intended to limit the scope of the invention, so that equivalent changes or modifications in the structure, features and principles described in the present invention should be included in the claims of the present invention.
Claims (10)
1. The online monitoring system for the concentration of VOCs in the oil gas recovery system of the finished oil depot is characterized by comprising a control system and field detection equipment;
the control system comprises a light source generating device, a photoelectric detector, a data acquisition card and a computer, wherein light generated by the light source generating device enters field detection equipment through optical fibers, light coming out of the field detection equipment enters the photoelectric detector through the optical fibers, and the photoelectric detector is connected with the data acquisition card; the data acquisition card of the light source generating device is connected with the computer;
the on-site detection equipment comprises a gas pool, a laser collimating mirror, a temperature sensor and a gas pressure sensor, wherein the gas pool is divided into a detection gas pool and a reference gas pool, an incident light port and an emergent light port are formed below the gas pool, and a reflector is arranged on the inner side above the gas pool; the laser collimating lens is arranged at the position of the incident light port and the emergent light port and is connected with the optical fiber; and the temperature sensor and the air pressure sensor are connected with the data acquisition card.
2. The online monitoring system for the concentration of VOCs in the oil and gas recovery system of the finished oil depot according to claim 1, wherein the light source generating device comprises a laser controller, a semiconductor laser and an optical fiber coupler which are sequentially connected, and the optical fiber coupler is connected with on-site detection equipment through an optical fiber; the laser controller is also connected with a computer.
3. The on-line monitoring system for VOCs concentration of oil and gas recovery system of finished oil depot according to claim 1, wherein the semiconductor laser is a DFB tunable semiconductor laser and the generation characteristic is that the central wave number is 3081cm -1 With a period of 1s at 1cm -1 Sawtooth-shaped sweep-frequency light within the range.
4. The online monitoring system for the concentration of VOCs in the oil and gas recovery system of the finished oil depot according to claim 1, wherein the optical fiber coupler is a 1 x 2 single-mode optical fiber coupler, FC flange interfaces are used at two ends, and the splitting ratio is 50; the optical fiber is an aluminum trifluoride glass optical fiber.
5. The system for monitoring the concentration of VOCs in the oil and gas recovery system of the finished oil depot according to claim 1, wherein the data acquisition card comprises a photoelectric data acquisition card, a temperature data acquisition card and an air pressure data acquisition card, and the photoelectric detector, the temperature sensor and the air pressure sensor are respectively connected with the photoelectric data acquisition card, the temperature data acquisition card and the air pressure data acquisition card.
6. The online monitoring system for the concentration of VOCs in the oil and gas recovery system of the finished oil depot according to claim 1, wherein the gas tank is provided with gas holes around the body, the detection gas tank is arranged at a discharge port and a leakage point of the oil and gas recovery system, and the reference gas tank is arranged at a safe region.
7. The on-line monitoring system for the concentration of VOCs in the oil and gas recovery system of the finished oil depot according to claim 1, wherein the reflector is metal film plated glass; the laser collimating lens uses FC flange interface at the tail and AR film plating aspheric lens at the head.
8. The on-line monitoring system for the concentration of VOCs in the oil and gas recovery system of the finished oil depot according to claim 1, wherein the photoelectric detector is made of indium-arsenic-antimony material to detect light in a wavelength band of 2000nm to 5000 nm.
9. The method for monitoring the concentration of VOCs in the oil gas recovery system of the finished oil depot by using the online monitoring system as claimed in claim 1 is characterized by comprising the following steps:
(1) Analyzing and determining easy leakage points of an oil gas recovery system of a finished oil depot, and setting the on-site detection equipment of any one of claims 1 to 8 aiming at a discharge port and the easy leakage points of the oil gas recovery system;
(2) The light source generating device emits light with a central wave number of 3081cm -1 The period is 1s and is 1cm -1 The sawtooth frequency-sweeping light in the range is coupled into the optical fiber and then divided into two paths;
(3) Light passes through a laser collimating lens along an optical fiber, one path of light enters a detection gas pool, and the other path of light enters a reference gas pool;
(4) The light enters the gas pool, is reflected by the reflector, is re-coupled into the optical fiber by the laser collimating mirror and is transmitted to the photoelectric detector;
(5) The data acquisition card acquires data output by the photoelectric detector, the temperature sensor and the air pressure sensor;
(6) And after the data acquisition card transmits the data to a computer, the concentration of VOCs at the discharge port and the easy leakage point of the oil gas recovery system is calculated, and a user monitors the concentration of VOCs at the discharge port and the easy leakage point of the oil gas recovery system of the finished oil depot on line through a human-computer interaction interface.
10. The monitoring method according to claim 10,
in the step (6), the concentration of VOCs is calculated by adopting the following formula:
wherein the content of the first and second substances,c general assembly The concentration of VOCs at the monitored point of the oil gas recovery system is represented, and the concentration of olefin at the monitored point of the oil gas recovery system is represented by c; h 0 Represents a direct current component; s (T) represents the gas absorption line intensity; t represents the real-time temperature near the oil gas recovery system of the reservoir area; l is an effective detection optical path; Δ v c Representing full width at half maximum.
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| US20220056824A1 (en) * | 2020-08-20 | 2022-02-24 | Denso International America, Inc. | Diagnostic systems and methods of vehicles using olfaction |
| US11828210B2 (en) * | 2020-08-20 | 2023-11-28 | Denso International America, Inc. | Diagnostic systems and methods of vehicles using olfaction |
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