Fuel calorific value measurement method and device

Abstract

The present invention discloses a fuel calorific value measurement method and device, which relates to the field of calorific value measurement technology. The method comprises the following steps: obtaining a sample gas; pre-treating the sample gas, allowing the pre-treated sample gas to enter a micro-burner assembly for combustion to generate flue gas; sampling and recording the numerical values ​​of flue gas components using a flue gas analyzer; establishing a relationship diagram between flue gas components and the calorific value of the fuel using a numerical analysis method; and obtaining the calorific value of the fuel. The present invention reduces the cost of calorific value measurement equipment, lowers the user access level, eliminates maintenance, and achieves real-time calorific value measurement, meeting the needs of small and micro users for low-cost, maintenance-free energy meters while ensuring high measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of calorific value measurement, and more particularly to a method and device for measuring the calorific value of fuel. Background Art

[0002] Currently, natural gas calorific value is commonly determined using gas chromatography, which measures components and calculates the calorific value. This method requires high equipment investment, complex maintenance, and skilled personnel for operation and maintenance. Furthermore, this method takes approximately 15 to 30 minutes to analyze a single sample, making real-time sampling and analysis impossible. Other methods that measure calorific value based on natural gas physical properties require extensive parameter databases, resulting in high development costs.

[0003] For low-pressure natural gas users such as small and micro enterprises and households that do not have the same metering conditions as gate stations, there is still a lack of corresponding natural gas energy metering equipment, and new calorific value measurement equipment is urgently needed to be developed.

[0004] Therefore, how to provide a fuel calorific value measurement method and equipment that can reduce development costs while ensuring high measurement accuracy and achieve real-time sampling and analysis is an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] In light of this, the present invention provides a method and device for measuring the calorific value of fuel. Analysis of combustion products reveals that the primary combustion products of natural gas are carbon dioxide and water. Clearly, the lower the ratio of carbon dioxide and water in the combustion products, the higher the calorific value of the natural gas. Therefore, by establishing a relationship between the composition of combustion products and the calorific value of natural gas, the calorific value of natural gas can be conveniently measured indirectly through flue gas analysis. This reduces the cost of calorific value measurement equipment, lowers the level of user access, eliminates maintenance, and enables real-time calorific value measurement, meeting the needs of small and micro-sized users for low-cost, maintenance-free energy meters while ensuring high measurement accuracy.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: a method for measuring the calorific value of fuel, comprising:

[0007] Obtaining sample gas;

[0008] The sample gas is pretreated, and the pretreated sample gas enters the micro burner assembly and burns to generate flue gas;

[0009] Use a flue gas analyzer to sample and record the values ​​of flue gas components;

[0010] Use numerical analysis methods to establish the relationship diagram between flue gas components and fuel calorific value;

[0011] Get the calorific value of the fuel.

[0012] Preferably, the flue gas components include CO2, CO, NO X , SO2, O2; the values ​​include the percentage of flue gas components, moisture content and temperature and pressure of the flue gas.

[0013] Preferably, pre-processing the sample gas includes: filtering the sample gas through a filter;

[0014] Regulating the pressure of the sample gas by a pressure reducing valve;

[0015] The flow rate of the sample gas is adjusted by a flow regulating valve.

[0016] Preferably, the pretreated sample gas enters the micro-burner assembly for combustion, comprising:

[0017] Controlling the shutoff valve to open, the sample gas enters the micro-burner assembly, and introducing air into the micro-burner assembly to completely burn the sample gas;

[0018] The control shut-off valve is closed, and the sample gas is stopped from entering the micro burner assembly.

[0019] Preferably, the fuel calorific value is obtained by establishing a relationship diagram between the flue gas components and the calorific value of the fuel using a numerical analysis method, including: calculating the carbon-hydrogen ratio in the flue gas components according to the numerical values ​​of the flue gas components;

[0020] The formula for calculating the carbon-hydrogen ratio is as follows:

[0021]

[0022] Where, Ψ represents the carbon-hydrogen ratio; is the amount of carbon dioxide in the flue gas, is the amount of carbon monoxide in the flue gas, The amount of water in the flue gas. The amount of moisture in the air that is carried into the flue gas;

[0023] According to the calculation results of the carbon-hydrogen ratio, the corresponding fuel calorific value is obtained by querying the calorific value relationship diagram.

[0024] Preferably, the sample gas is natural gas; and the fuel calorific value is the calorific value of natural gas.

[0025] A fuel calorific value measuring device, applied to the above-mentioned fuel calorific value measuring method, comprising: a sample gas sampling pipeline, a micro burner assembly, a flue gas analyzer and a control module;

[0026] The sample gas sampling pipeline, the micro burner assembly, and the flue gas analyzer are respectively connected to the control module;

[0027] The sample gas sampling pipeline is connected to the micro burner assembly;

[0028] The micro burner assembly is connected to the flue gas analyzer.

[0029] Preferably, the sample gas sampling pipeline comprises: a sample gas container, a filter, a sampling isolation valve, a pressure reducing valve, a flow regulating valve and a stop valve connected in sequence;

[0030] The control module controls the opening and closing of the stop valve.

[0031] Preferably, the micro burner assembly includes: a small burner, an ignition gun, a blower, a flue and a drain valve; wherein the ignition gun and the blower are controlled by a control module;

[0032] The flue is connected to the drain valve;

[0033] The flue is connected to the flue gas analyzer;

[0034] The small burner is communicated with the sample gas sampling pipeline and is used for introducing the sample gas and burning it through the ignition gun.

[0035] Preferably, the control module includes a control unit, a processing unit and a display unit;

[0036] The control unit is used to control the stop valve, ignition gun and air blower;

[0037] The processing unit is used to receive the value output by the flue gas analyzer and calculate the calorific value of the fuel;

[0038] The display unit is used to display the calorific value of the fuel.

[0039] It can be seen from the above technical solution that compared with the prior art, the present invention discloses a method and device for measuring the calorific value of fuel, including: obtaining sample gas; pre-treating the sample gas, and the pre-treated sample gas enters a micro-burner assembly for combustion to generate flue gas; using a flue gas analyzer to sample and record the numerical values ​​of flue gas components; using a numerical analysis method to establish a relationship diagram between flue gas components and the calorific value of fuel; and obtaining the calorific value of the fuel.

[0040] The present invention has the following beneficial effects:

[0041] (1) For users who have their own flue gas component analysis, the present invention is more convenient for determining calorific value, and the calorific value can be calculated directly through the program without adding additional equipment.

[0042] (2) The micro-burner assembly simulates combustion conditions to measure the flue gas components, and the gas calorific value is calculated by the device provided by the present invention. It is small in size, low in cost, maintenance-free, and has no technical requirements for users, which is conducive to large-scale promotion and use.

[0043] (3) The present invention is based on flue gas component analysis and is not only applicable to natural gas, but can also be applied to the calorific value measurement of most fuels; and provides a more flexible way for the calorific value measurement of fuels, which can be used in both fixed and portable ways.

[0044] (4) The present invention can realize continuous measurement of fuel calorific value, is more sensitive to changes in calorific value, and has higher accuracy than intermittent measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0046] Figure 1 This is a flow chart of a fuel calorific value measurement method provided by the present invention.

[0047] Figure 2 This is a structural schematic diagram of a fuel calorific value measuring device provided by the present invention.

[0048] Figure 3 This is a relationship diagram between the carbon-hydrogen ratio and the calorific value of the fuel provided by the present invention.

[0049] Among them, 1-sample gas container, 2-filter, 3-sampling isolation valve, 4-pressure reducing valve, 5-flow regulating valve, 6-stop valve, 7-small burner, 8-ignition gun, 9-air blower, 10-control module, 11-flue gas analyzer, 12-flue duct, 13-drain valve. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] An embodiment of the present invention discloses a method and device for measuring the calorific value of a fuel, comprising: obtaining a sample gas; pre-treating the sample gas, allowing the pre-treated sample gas to enter a micro-burner assembly for combustion to generate flue gas; sampling and recording the numerical values ​​of flue gas components using a flue gas analyzer; establishing a relationship diagram between the flue gas components and the calorific value of the fuel using a numerical analysis method; and obtaining the calorific value of the fuel. This embodiment of the present invention reduces the cost of calorific value measurement equipment, lowers the user access level, eliminates maintenance, and achieves real-time calorific value measurement, meeting the needs of small and micro users for low-cost, maintenance-free energy meters while ensuring high measurement accuracy.

[0052] Example 1

[0053] This embodiment discloses a method for measuring the calorific value of fuel. Figure 1 As shown, the method includes: obtaining sample gas; pre-treating the sample gas, allowing the pre-treated sample gas to enter a micro-burner assembly for combustion to generate flue gas; using a flue gas analyzer to sample and record the values ​​of flue gas components; using a numerical analysis method to establish a relationship diagram between flue gas components and the calorific value of fuel, and obtaining the calorific value of the fuel by calculating the carbon-hydrogen ratio.

[0054] Specifically, the embodiment of the present invention establishes a calorific value database through a large number of experiments, and then obtains the calorific value relationship between the flue gas components and the fuel, and establishes a calorific value relationship diagram between the flue gas components and the fuel. Taking the carbon-hydrogen ratio in the flue gas components as an example, Figure 3 As shown, with the carbon-hydrogen ratio as the horizontal axis and the calorific value of the fuel as the vertical axis, a relationship diagram between the carbon-hydrogen ratio and the calorific value of the fuel is established; the calorific value of the fuel is obtained by looking up the diagram through the calculated carbon-hydrogen ratio.

[0055] Specifically, the flue gas components include CO2, CO, NO X , SO2, O2; the values ​​include the percentage of flue gas components, moisture content and temperature and pressure of the flue gas.

[0056] Specifically, the sample gas is pretreated, including: filtering the sample gas through a filter; regulating the pressure of the sample gas through a pressure reducing valve; regulating the flow of the sample gas through a flow regulating valve; adjusting the flow and pressure of the sampling gas, and ensuring the cleanliness of the sample gas.

[0057] Specifically, the pretreated sample gas enters the micro-burner assembly for combustion, including: controlling the shut-off valve to open, allowing the sample gas to enter the micro-burner assembly, introducing air into the micro-burner assembly to ensure complete combustion of the sample gas; controlling the shut-off valve to close, stopping the sample gas from entering the micro-burner assembly.

[0058] The specific numerical analysis method includes: using the ideal gas state equation: PV = NRT, calculating the molar volume Vm of each gas component per unit amount of substance under corresponding working conditions:

[0059]

[0060] Where N=1, P is the flue gas pressure, R is the ideal gas constant, and T is the thermodynamic temperature of the flue gas.

[0061] Furthermore, a numerical analysis method is used to establish a relationship diagram between the flue gas components and the calorific value of the fuel to obtain the calorific value of the fuel, including: calculating the carbon-hydrogen ratio of the flue gas components according to the numerical values ​​of the flue gas components;

[0062] The formula for calculating the carbon-hydrogen ratio is as follows:

[0063]

[0064] Where, Ψ represents the carbon-hydrogen ratio; is the amount of carbon dioxide in the flue gas, is the amount of carbon monoxide in the flue gas, The amount of water in the flue gas. The amount of moisture in the air that is carried into the flue gas;

[0065] According to the calculation results of the carbon-hydrogen ratio, the corresponding fuel calorific value is obtained by querying the calorific value relationship diagram.

[0066] Specifically, the sample gas is natural gas; and the fuel calorific value is the calorific value of natural gas.

[0067] Example 2

[0068] This embodiment discloses a fuel calorific value measuring device, such as Figure 2 As shown, it includes: a sample gas sampling pipeline, a micro burner assembly, a flue gas analyzer 11 and a control module 10; the sample gas sampling pipeline, the micro burner assembly, and the flue gas analyzer 11 are respectively connected to the control module 10; the sample gas sampling pipeline is connected to the micro burner assembly; the micro burner assembly is connected to the flue gas analyzer 11.

[0069] Specifically, the sample gas sampling pipeline includes: a sample gas container 1, a filter 2, a sampling isolation valve 3, a pressure reducing valve 4, a flow regulating valve 5 and a stop valve 6 connected in sequence; a control module 10 controls the opening and closing of the stop valve 6.

[0070] Specifically, the micro burner assembly includes: a small burner 7, an ignition gun 8, an air blower 9, a flue 12 and a drain valve 13; wherein, the ignition gun 8 and the air blower 9 are controlled by a control module 10; the flue 12 and the drain valve 13 are connected; the flue 12 is connected to the flue gas analyzer 11; the small burner 7 is connected to the sample gas sampling pipeline, which is used to introduce sample gas and burn it through the ignition gun 8.

[0071] Specifically, the control module 10 includes a control unit, a processing unit and a display unit; the control unit is used to control the stop valve 6, the ignition gun 8 and the air blower 9; the processing unit is used to receive the numerical value output by the flue gas analyzer 11 and calculate the calorific value of the fuel; the display unit is used to display the calorific value of the fuel.

[0072] Example 3

[0073] This embodiment discloses a method for measuring the calorific value of natural gas, comprising: introducing excess air into a micro burner 7 to completely burn the sample gas, sampling and recording CO2, CO, NO in the flue gas using a flue gas analyzer 11, and X , SO2, O2, and other components, as well as moisture content, calculate the carbon-to-hydrogen ratio of the flue gas components, and compare the carbon-to-hydrogen ratio with the fuel's calorific value to directly obtain the fuel's calorific value. The main components of this embodiment include: a sample gas sampling pipeline, a micro-burner assembly, a flue gas analyzer 11, and a control module 10. Furthermore, users with their own flue gas analyzer 11 can directly calculate the calorific value of natural gas using combustion flue gas products.

[0074] Among them, the sample gas sampling pipeline mainly includes: a filter 2, a sampling isolation valve 3, a pressure reducing valve 4, a flow regulating valve 5, and a stop valve 6 controlled by a control unit 10, which can adjust the flow and pressure of the sampled gas and ensure the cleanliness of the gas.

[0075] The micro burner assembly mainly includes: a small burner 7, an ignition gun 8, a blower 9, a flue, a sewage valve 13, etc., wherein the ignition gun 8 and the blower 9 are controlled by a control unit 10.

[0076] The flue gas analyzer 11 is connected to the tail flue of the micro burner, sampling and analyzing from the tail flue, and measuring the content of combustion products in the sample gas, mainly including: CO2, CO, NO X , SO2, O2 and other components as well as the moisture content, and measure the temperature and pressure of the flue gas.

[0077] The control unit 10 is mainly used to control the ignition of the micro burner, receive data from the gas analyzer, obtain the percentage of flue gas component content, and calculate and generate corresponding calorific value data.

[0078] The calculation method is to calculate the carbon-hydrogen ratio in the sample gas through the flue gas components, and obtain the calorific value of the sample gas through the carbon-hydrogen ratio and calorific value relationship curve built into the system.

[0079] Furthermore, the calculation method is: using the ideal gas state equation: PV=NRT to calculate the molar volume Vm of each gas component under corresponding working conditions.

[0080] For example, the formula for calculating the carbon-hydrogen ratio is:

[0081]

[0082] Where: Ψ is the carbon-hydrogen ratio in the flue gas components, is the amount of carbon dioxide in the flue gas, is the amount of carbon monoxide in the flue gas, The amount of water in the flue gas. It indicates the amount of moisture in the air brought into the flue gas.

[0083] The calorific value of the sample gas is obtained based on the calculated carbon-hydrogen ratio using the system's built-in carbon-hydrogen ratio and calorific value relationship curve.

[0084] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0085] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for measuring the calorific value of fuel, characterized in that: include: Obtaining sample gas; The sample gas is pretreated, and the pretreated sample gas enters the micro burner assembly and burns to generate flue gas; Use a flue gas analyzer to sample and record the values ​​of flue gas components; The numerical analysis method is used to establish the relationship diagram between flue gas components and fuel calorific value to obtain the fuel calorific value; A numerical analysis method is used to establish a relationship diagram between the flue gas components and the calorific value of the fuel to obtain the calorific value of the fuel, including: calculating the carbon-hydrogen ratio of the flue gas components according to the numerical values ​​of the flue gas components; The formula for calculating the carbon-hydrogen ratio is as follows: Where, Ψ represents the carbon-hydrogen ratio; is the amount of carbon dioxide in the flue gas, is the amount of carbon monoxide in the flue gas, The amount of water in the flue gas. The amount of moisture in the air that is carried into the flue gas; According to the calculation results of the carbon-hydrogen ratio, the corresponding fuel calorific value is obtained by querying the calorific value relationship diagram.

2. A fuel calorific value measurement method according to claim 1, characterized in that: The flue gas components include CO2, CO, NO X , SO2, O2; the values ​​include the percentage of flue gas components, moisture content and temperature and pressure of the flue gas.

3. A fuel calorific value measurement method according to claim 1, characterized in that: Pre-processing the sample gas includes: filtering the sample gas through a filter; Regulating the pressure of the sample gas by a pressure reducing valve; The flow rate of the sample gas is adjusted by a flow regulating valve.

4. A fuel calorific value measurement method according to claim 1, characterized in that: The pre-treated sample gas enters the micro burner assembly for combustion, including: Controlling the shutoff valve to open, the sample gas enters the micro-burner assembly, and introducing air into the micro-burner assembly to completely burn the sample gas; The control shut-off valve is closed, and the sample gas is stopped from entering the micro burner assembly.

5. A fuel calorific value measurement method according to claim 1, characterized in that: The sample gas is natural gas; and the fuel calorific value is the calorific value of natural gas.

6. A fuel calorific value measuring device, applied to a fuel calorific value measuring method according to any one of claims 1 to 5, characterized in that: include: A sample gas sampling pipeline, a micro burner assembly, a flue gas analyzer (11) and a control module (10); The sample gas sampling pipeline, the micro burner assembly, and the flue gas analyzer (11) are respectively connected to the control module (10); The sample gas sampling pipeline is connected to the micro burner assembly; The micro burner assembly is connected to the flue gas analyzer (11).

7. A fuel calorific value measuring device according to claim 6, characterized in that: The sample gas sampling pipeline comprises: a sample gas container (1), a filter (2), a sampling isolation valve (3), a pressure reducing valve (4), a flow regulating valve (5) and a stop valve (6) connected in sequence; The control module (10) controls the opening and closing of the stop valve (6).

8. A fuel calorific value measuring device according to claim 6, characterized in that: The micro burner assembly comprises: a small burner (7), an ignition gun (8), a blower (9), a flue (12) and a drain valve (13); wherein the ignition gun (8) and the blower (9) are controlled by a control module (10); The flue (12) is connected to the sewage valve (13); The flue (12) is in communication with the flue gas analyzer (11); The small burner (7) is in communication with the sample gas sampling pipeline and is used for introducing the sample gas and burning it through the ignition gun (8).

9. A fuel calorific value measuring device according to claim 6, characterized in that: The control module (10) includes a control unit, a processing unit and a display unit; The control unit is used to control the stop valve (6), the ignition gun (8) and the air blower (9); The processing unit is used to receive the value output by the flue gas analyzer (11) and calculate the calorific value of the fuel; The display unit is used to display the calorific value of the fuel.

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