1. The utility model provides a natural gas combustible gas component concentration on-line measuring device which characterized in that includes: a gas pipeline, an air inlet pipe, a gas chamber packaging sub-device, a transparent window, an LED array, a first condensing lens, a second condensing lens, a pressure sensor, a temperature sensor, a data acquisition card, a PC (personal computer), a spectrometer, an electronic control unit, a gas engine and an exhaust pipe, wherein,

one end of the gas pipeline is a natural gas inlet, and the other end of the gas pipeline is connected with the gas engine; the intake pipe respectively with the gas pipeline with gas chamber encapsulation sub-device connects, gas chamber encapsulation sub-device with the blast pipe is connected, gas chamber encapsulation sub-device both ends are equipped with transparent window respectively, and two transparent windows all set up a condensing lens, near intake pipe's the first condensing lens outside is equipped with the LED array, near blast pipe's the second condensing lens outside is equipped with the spectrum appearance, pressure sensor with temperature sensor's one end all sets up the inside of gas chamber encapsulation sub-device, pressure sensor with temperature sensor's the other end with data acquisition card connects, the PC respectively with data acquisition card LED array with the spectrum appearance is connected, electronic control unit respectively with gas engine with the PC is connected.

2. The on-line measuring device for the concentration of the natural gas combustible gas components according to claim 1, wherein the LED array comprises m LED light sources with different central wavelengths, and the LED light sources are sequentially lightened by the PC.

3. The on-line measuring device for the concentration of the natural gas combustible gas component of claim 1, wherein the transparent window is used for injecting the light processed by the first condenser lens into the gas chamber packaging sub-device and injecting the light passing through the gas chamber packaging sub-device to the second condenser lens.

4. The on-line measuring device for the concentration of the natural gas combustible gas components according to claim 1, wherein the spectrometer is used for measuring absorbance signals of light with different central wavelengths which is converted into collimated light through the first condenser lens and the second condenser lens.

5. The on-line measuring device for the natural gas combustible gas component concentration according to claim 1, wherein the pressure sensor is used for measuring a natural gas pressure value in the gas chamber packaging sub-device, and the temperature sensor is used for measuring a natural gas temperature value in the gas chamber packaging sub-device.

6. The on-line measuring device for the component concentration of natural gas and combustible gas of claim 1, wherein the data acquisition card is used for acquiring a pressure value of the pressure sensor and a temperature value of the temperature sensor.

7. The on-line measuring device for the concentration of the natural gas combustible gas components according to claim 1, wherein the PC is used for solving the concentration of the components in the mixed gas according to the beer-Lambert law by processing the pressure value, the temperature value and the absorbance signal.

8. The on-line measuring device for the concentration of the natural gas combustible gas components according to claim 1, wherein the electronic control unit regulates the gas engine according to the concentration of the mixed gas components calculated by the PC.

Background

With the increasing demand for energy conservation and environmental protection and the stricter emission regulations, the clean and low-carbon fossil fuel, natural gas, receives more and more attention, and natural gas engines are widely paid attention due to the characteristics of good thermal efficiency and low emission. The natural gas fuel mainly comprises mixed gas of methane, ethane, propane, butane, carbon dioxide, nitrogen and the like. Firstly, natural gas sources are different, geographical position differences, seasonal changes of natural gas quality and differences of manufacturers and preparation processes cause in-situ differences of natural gas quality, secondly, a large-scale natural gas pipeline network switches valves and adjusts flow rate, lighter molecules of an liquefied natural gas tank evaporate before heavier molecules, and sudden changes of the torque of a propeller of an liquefied natural gas ship cause changes of gas flow flowing to an engine, so that differences of the natural gas quality in the using process are caused.

Research shows that the Otto cycle engine is very sensitive to the quality change of natural gas, and methane value and heat value are used as evaluation indexes for evaluating the quality of the natural gas and are widely concerned at home and abroad. No matter the methane value of natural gas or the heat value of the natural gas is researched, the core problem of researching the concentration of combustible gas components of the natural gas is not solved, methane, ethane, propane and butane are used as the combustible gas components in the natural gas, the unstable operation of an Otto cycle engine can be brought by the rapid change of the component concentration, and the flameout of the engine, the abnormal starting of the engine and even the damage of the engine can be caused under some conditions.

Therefore, a device capable of measuring the component concentration of the natural gas combustible gas in real time on line is urgently needed, and the change of the component concentration of the natural gas combustible gas is known in time so as to adjust the engine correspondingly.

Disclosure of Invention

The present invention is directed to solving, to some extent, one of the technical problems in the related art.

Therefore, the invention provides an on-line measuring device for the concentration of the components of the natural gas combustible gas.

In order to achieve the above object, an embodiment of the present invention provides an online measurement apparatus for a component concentration of a natural gas combustible gas, including: the gas-powered LED comprises a gas pipeline, a gas inlet pipe, a gas chamber packaging sub-device, a transparent window, an LED array, a first condensing lens, a second condensing lens, a pressure sensor, a temperature sensor, a data acquisition card, a PC (personal computer), a spectrometer, an electronic control unit, a gas engine and an exhaust pipe, wherein one end of the gas pipeline is a natural gas inlet, and the other end of the gas pipeline is connected with the gas engine; the intake pipe respectively with the gas pipeline with gas chamber encapsulation sub-device connects, gas chamber encapsulation sub-device with the blast pipe is connected, gas chamber encapsulation sub-device both ends are equipped with transparent window respectively, and two transparent windows all set up a condensing lens, near intake pipe's the first condensing lens outside is equipped with the LED array, near blast pipe's the second condensing lens outside is equipped with the spectrum appearance, pressure sensor with temperature sensor's one end all sets up the inside of gas chamber encapsulation sub-device, pressure sensor with temperature sensor's the other end with data acquisition card connects, the PC respectively with data acquisition card LED array with the spectrum appearance is connected, electronic control unit respectively with gas engine with the PC is connected.

The online measuring device for the component concentration of the combustible natural gas overcomes the problems of engine flameout, abnormal operation, calculation of natural gas heat value and natural gas anti-knock performance index methane number and the like caused by rapid change of the component concentration of the combustible natural gas, and has the advantages of online, real-time, high precision, low cost, compact structure, rapid reaction, non-contact measurement and the like.

In addition, the online measuring device for the concentration of the natural gas combustible gas component according to the embodiment of the invention can also have the following additional technical characteristics:

further, in an embodiment of the present invention, the LED array includes m LED light sources with different center wavelengths, and the LED light sources are sequentially turned on by the PC.

Further, in an embodiment of the present invention, the transparent window is configured to inject the light processed by the first condenser lens into the gas chamber sealing sub-device, and to inject the light passing through the gas chamber sealing sub-device to the second condenser lens.

Further, in an embodiment of the present invention, the spectrometer is configured to measure absorbance signals of light of different center wavelengths that is converted into collimated light by the first condenser lens and the second condenser lens.

Further, in an embodiment of the present invention, the pressure sensor is configured to measure a pressure value of natural gas in the gas chamber packaging sub-assembly, and the temperature sensor is configured to measure a temperature value of natural gas in the gas chamber packaging sub-assembly.

Further, in an embodiment of the present invention, the data acquisition card is configured to acquire a pressure value of the pressure sensor and a temperature value of the temperature sensor.

Further, in one embodiment of the present invention, the PC processes the pressure, temperature and absorbance signals according to the beer-Lambert law to solve for the mixed gas component concentrations.

Further, in one embodiment of the present invention, the electronic control unit regulates the gas engine based on the mixed gas component concentration calculated by the PC.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural diagram of an on-line measuring device for the concentration of combustible gas components in natural gas according to an embodiment of the invention;

fig. 2 is a schematic structural diagram of an LED array in an online measuring device for the concentration of a natural gas combustible gas component according to an embodiment of the invention.

Description of reference numerals: the device comprises a 100-natural gas combustible gas component concentration online measuring device, a 1-gas pipeline, a 2-gas engine, a 3-gas inlet pipe, a 4-gas chamber packaging sub-device, a 5-gas outlet pipe, a 6-transparent window, a 7-first condensing lens, an 8-second condensing lens, a 9-LED array, a 91-LED light source, a 10-spectrometer, an 11-pressure sensor, a 12-temperature sensor, a 13-data acquisition card, a 14-PC and a 15-electronic control unit.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

The on-line measuring device for the concentration of the combustible gas component of the natural gas according to the embodiment of the invention is described below with reference to the attached drawings.

Fig. 1 is a schematic structural diagram of an on-line measuring device for the concentration of a natural gas combustible gas component according to an embodiment of the invention.

As shown in fig. 1, the apparatus 100 includes: the device comprises a gas pipeline 1, a gas engine 2, an air inlet pipe 3, a gas chamber packaging sub-device 4, an air outlet pipe 5, a transparent window 6, a first condenser lens 7, a second condenser lens 8, an LED array 9, a spectrometer 10, a pressure sensor 11, a temperature sensor 12, a data acquisition card 13, a PC (personal computer) 14 and an Electronic Control Unit (ECU) 15.

Wherein, one end of the gas pipeline 1 is a natural gas inlet, and the other end is connected with the gas engine 2; the gas inlet pipe 3 is respectively connected with the gas pipeline 1 and the gas chamber packaging sub-device 4, the gas chamber packaging sub-device 4 is connected with the gas exhaust pipe 5, transparent windows 6 are respectively arranged at two ends of the gas chamber packaging sub-device 4, each transparent window 6 is provided with a condensing lens, an LED array 9 is arranged on the outer side of a first condensing lens 7 near the gas inlet pipe 3, a spectrometer 10 is arranged on the outer side of a second condensing lens 8 near the gas exhaust pipe 5, one ends of a pressure sensor 11 and a temperature sensor 12 are respectively arranged in the gas chamber packaging sub-device 4, the other ends of the pressure sensor 11 and the temperature sensor 12 are connected with a data acquisition card 13, a PC 14 is respectively connected with the data acquisition card 13, the LED array 9 and the spectrometer 10, and an ECU15 is respectively connected with the gas engine 2.

Furthermore, the gas pipeline 1, the gas inlet pipe 3, the gas chamber packaging sub-device 4, the transparent window 6 and the exhaust pipe 5 in the embodiment of the invention form a gas component circulation and sealing part, so that the gas leakage phenomenon cannot occur; the LED array 9, the condensing lens, the incident light, the PC 14 and the spectrometer 10 form a fuel gas component detection part; the pressure sensor 11, the temperature sensor 12, the data acquisition card 13, the PC 14, the spectrometer 10, the ECU15 and the gas engine 2 form a signal acquisition and transmission part.

Further, as shown in fig. 2, the LED array 9 includes m LED light sources (91, etc.) with different central wavelengths, the LED light sources are sequentially turned on by the PC 14, specifically, the central wavelengths of each LED light source in the LED array 9 are different, the number of the LED light sources in the LED array 9 depends on the size of m in the operational equation matrix, and the PC 14 controls the LED light sources to be sequentially turned on, and the lights with different wavelengths are sequentially detected by the spectrometer 10 to obtain absorbance signals thereof. The LED light source has the advantages of stable light, high reliability, easy miniaturization integration, long service life, strong adaptability to severe environment and low price.

Wherein, the operation equation matrix is:

[Z]＝lg^e·L·[X][Y] (1)

wherein, the matrix equation [ X ] under the conditions of temperature and pressure]By a pair matrix [ Z ]]By measuring, the matrix [ Y ] can be solved]In addition, [ X ]]Lambda of rear₁Lλ_mIs meant to denote the interpretation matrix X, and is merely a notation, meaning that the first row represents λ₁The measured data is not part of the equation.

Further, the transparent window 6 is used for injecting the light processed by the first condenser lens 7 into the gas chamber packaging sub-device 4 and injecting the light passing through the gas chamber packaging sub-device 4 to the second condenser lens 8.

Further, the spectrometer 10 is used to measure absorbance signals of light of different center wavelengths that are changed into collimated light by the first condenser lens 7 and the second condenser lens 8.

Further, the pressure sensor 11 is used for measuring the pressure value of the natural gas in the gas chamber packaging sub-device 4, and the temperature sensor 12 is used for measuring the temperature value of the natural gas in the gas chamber packaging sub-device 4.

Further, the data acquisition card 13 is used for acquiring the pressure value of the pressure sensor 11 and the temperature value of the temperature sensor 12.

Further, the PC 14 processes the pressure value, the temperature value and the absorbance signal according to the beer-Lambert law to solve the component concentration of the mixed gas.

Specifically, this section relates to absorbance calculations, linear superposition of absorbance, absorption spectra, beer-lambert law, matrix equation operations, multi-wavelength fitting, and the like.

The absorbance is defined as follows:

wherein, A absorbance, I₀Initial light intensity, I_tThe intensity of the transmitted light;

the beer-Lambert is defined as follows:

wherein the content of the first and second substances,gas absorption cross section, L optical path, C gas concentration;

the following equation (4) can be found:

from the linear superposition of the absorbances:

A＝A₁+A₂+…+A_m (6)

the absorbance is determined by wavelength, temperature, pressure and optical path, and the absorption cross section under different wavelength, temperature and pressure conditions needs to be measured in advance in the measurement system, namely [ X ] in the formula (2)]Matrix, [ X ]]The matrix is an mxn-order matrix, m represents the number of different LED light sources, n represents the number of components of the mixed gas to be measured, and m is larger than or equal to n, when m is equal to n, the unknown concentration number is equal to the number of solving equations, and the matrix [ Y ] can be directly obtained]When m is greater than n, the number of the representative equations is greater than the unknown concentration number, so that the existing matrix equation has no definite solution, the reliability is set to be epsilon (for example, epsilon is 0.05), and when the matrix [ X ] is used][Y_{Solution (II)}]Result of (A) [ Z ]_{Solution (II)}]Satisfy, | A_{Solution of m}-A_mLess than or equal to epsilon, namely the matrix [ Y |)_{Solution (II)}]When m is larger than n, the accuracy of concentration solution can be improved.Represents the absorption cross section of the nth component at the mth wavelength under certain temperature and pressure conditions. Matrix [ Z ]]Is an m × 1 order matrix representing m absorbance results measured, wherein the initial intensity I₀Measured without the introduction of a fuel gas component. Matrix [ Y]Is an n × 1 order matrix representing the respective concentrations of the n mixture components.

By sorting the formula (5) and the formula (6) and combining multi-wavelength solution, the matrix equation of the formula (1) and the component concentration [ Y ] of the mixed gas can be obtained, wherein L is the optical path and the known parameters of the measuring system.

Further, the electronic control unit ECU15 regulates the gas engine in advance in accordance with the mixed gas component concentrations calculated by the PC 14.

Therefore, the specific working process of the embodiment of the invention is as follows: natural gas in a gas pipeline 1 flows into a gas chamber packaging sub-device 4 through a gas inlet pipe, the natural gas flows back to the gas pipeline 1 through a gas outlet pipe 5 after being filled into the gas chamber, an LED array 9 is powered by an LED power supply, a PC (personal computer) 14 controls the LED array 9 to sequentially light LED light sources in the array, so that the LED light sources with different wavelengths in the LED array 9 emit light with different wavelengths, the emitted light with different wavelengths and divergent light is converted into collimated light through a first condenser lens 7, the collimated light passes through a transparent window 6 and is incident into the gas chamber packaging sub-device 4, the light with different wavelengths is attenuated after the energy of the natural gas is absorbed by the natural gas, the initial light intensity and the light intensity (transmitted light intensity) absorbed by the natural gas satisfy the beer-Lambert law, the light passes through the gas chamber, passes through the transparent window 6 at the other end and is condensed by a second condenser lens 8, a spectrometer 10 detects an absorbance signal of the spectrometer 10, and transmits the detected absorbance signal to a PC end, the data acquisition card 13 transmits the acquired pressure signals and temperature signals to the PC 14, the component concentration of the natural gas and combustible gas is obtained through multi-wavelength fitting and matrix equation operation, and finally the ECU15 obtains the component concentration of the mixed gas to adjust the gas engine through calculation according to the PC 14.

According to the on-line measuring device for the component concentration of the natural gas combustible gas provided by the embodiment of the invention, the change of the component concentration of the natural gas combustible gas is measured on line in real time by collecting the natural gas which is introduced into the combustion chamber from a gas pipeline of the natural gas engine, the problems that the engine cannot normally run and the methane number and the calorific value of the natural gas fuel are calculated due to the rapid change of the component concentration of the combustible gas are solved, and the whole system has the advantages of simplicity in operation, low cost, strong adaptability to severe environments, low maintenance cost, safety, no pollution, real-time measurement, high reliability and the like.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.