A method for evaluating the applicability of fuel components based on hysteresis time

Abstract

The present invention discloses a method for evaluating the applicability of fuel components based on the hysteresis time, belonging to the technical field of gas turbines. In addition to judging whether the calorific value meets the requirements, the present invention introduces the hysteresis time as a criterion to further predict the change of the oscillation performance of the combustion chamber under the new fuel; and according to the hysteresis time, the equivalence ratio and the geometric structure of the burner are improved, which can be well applied to the judgment of the applicability of the new fuel.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas turbines, and particularly relates to a method for evaluating the applicability of fuel components based on the hysteresis time. Background Art

[0002] For a certain existing gas turbine, it has a definite designed fuel. If other fuels are to be burned, it is usually necessary to confirm through tests whether the combustion chamber of this type of gas turbine can burn the new fuel, so as to evaluate the combustion performance, with the focus on flashback and oscillation performance.

[0003] This method has a long cycle, high cost, and many iteration times. Therefore, a method for predicting the applicability of fuel is aimed at preliminarily judging whether the combustion chamber of a gas turbine can burn a certain type of new fuel before the test, so as to reduce the test cost and shorten the verification cycle.

[0004] The commonly used method at present is to judge the fuel by calculating the calorific value of the fuel through its components, but this method cannot evaluate the oscillation performance of combustion and is prone to misjudgment. Summary of the Invention

[0005] To solve the technical problems existing in the prior art, the present invention provides a method for evaluating the applicability of fuel components based on the hysteresis time. Besides judging whether the calorific value meets the requirements, the hysteresis time is introduced as a criterion to further predict the change in the oscillation performance of the combustion chamber under the new fuel; and according to the hysteresis time, the equivalence ratio and the geometric structure of the burner are improved, which can be well applied to the judgment of the applicability of the new fuel.

[0006] The present invention provides a method for evaluating the applicability of fuel components based on the hysteresis time, including the following steps:

[0007] Determine the components and the molar calorific value of the components of the new fuel;

[0008] Conduct a calorific value determination of the new fuel. If the calorific value of the new fuel does not meet the calorific value requirement of the designed fuel, it is considered that the new fuel is not applicable to this gas turbine; if the calorific value of the new fuel meets the calorific value requirement of the designed fuel, then based on the hysteresis time, the oscillation performance of the new fuel is predicted. If the oscillation amplitude is less than or equal to the allowable oscillation amplitude, it is considered that the oscillation risk of the new fuel is small and it can be used for this gas turbine; if the oscillation amplitude is greater than the allowable oscillation amplitude, it is considered that the new fuel is not applicable to this gas turbine.

[0009] Preferably, when conducting a calorific value determination of the new fuel, if the calorific value of the new fuel does not meet the calorific value requirement of the designed fuel, it is considered that the new fuel is not applicable to this gas turbine and the evaluation ends; if the calorific value of the new fuel meets the calorific value requirement of the designed fuel, then the specific steps for predicting the oscillation performance of the new fuel based on the hysteresis time include:

[0010] The mixed calorific value of the new fuel is calculated based on the molar fractions and calorific values of the components in the new fuel.

[0011] Compare the mixed calorific value of the new fuel with the calorific value requirement of the designed fuel. If the calorific value deviation is within the preset range, it is considered that the new fuel can meet the combustion requirements, and the oscillation performance of the new fuel is predicted based on the hysteresis time. If the calorific value deviation exceeds the preset range, it is considered that the new fuel is not applicable to this combustion engine.

[0012] Preferably, predicting the oscillation performance of the new fuel based on the hysteresis time includes the following steps:

[0013] Obtain the relationship curve between the hysteresis time t and the oscillation amplitude A of the designed fuel through experimental data and operating data.

[0014] Utilize the influence of hydrogen content and carbon monoxide content on the hysteresis time to correct the relationship curve between the hysteresis time and the oscillation amplitude, and obtain the corrected relationship curve between the hysteresis time and the oscillation amplitude.

[0015] Determine the oscillation amplitude A' at the designed hysteresis time point after using the new fuel according to the corrected relationship curve between the hysteresis time and the oscillation amplitude.

[0016] Preferably, the relationship curve between the hysteresis time t and the oscillation amplitude A of the designed fuel is fitted into a trigonometric function relationship curve, defined as A = asin(wt + b) + c, where a, w, b, and c are constant coefficients obtained by fitting experimental data and operating data.

[0017] Preferably, the corrected relationship curve between the hysteresis time and the oscillation amplitude is A' = asin(wt' + b) + c;

[0018] where, t' = t(1 - r H2 + r CO );

[0019] r H2 is the hydrogen correction coefficient, defined as ;

[0020] r CO is the carbon monoxide correction coefficient, defined as ;

[0021] where, k1, k2, t D , t CO and t H2 are given constants, m H2 is the hydrogen molar fraction, and m CO is the carbon monoxide molar fraction.

[0022] Preferably, if the oscillation amplitude is greater than the allowable oscillation amplitude and it is determined that the new fuel is not suitable for this combustion engine, the equivalence ratio and the structure of the burner are improved according to the hydrogen correction coefficient and the carbon monoxide correction coefficient.

[0023] Preferably, if 1 - r H2 + r CO is less than 1, it indicates that the hysteresis time is shortened, and the length of the premixed section of the burner is increased or the equivalence ratio in the combustion zone is decreased;

[0024] If 1 - r H2 + r CO is greater than 1, it indicates that the hysteresis time is increased, and the length of the premixed section of the burner is decreased or the equivalence ratio in the combustion zone is increased.

[0025] Preferably, the hysteresis time t of the fuel is obtained by acquiring the heat release signal through a flame detector or a camera, and then comparing the heat release signal with the pressure pulsation signal.

[0026] Preferably, the oscillation amplitude A is obtained from the pressure pulsation signal.

[0027] Preferably, the calorific value is calculated according to the GB / T 11062 standard, and the preset range of the calorific value is obtained from the fuel gas standard of the combustion engine.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] In addition to judging whether the calorific value meets the requirements, the present invention introduces the hysteresis time as a criterion to further predict the change in the oscillation performance of the combustion chamber under the new fuel; and according to the hysteresis time, the equivalence ratio and the geometric structure of the burner are improved, which can be well applied to the judgment of the applicability of the new fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the relationship curve between the hysteresis time and the oscillation amplitude of an embodiment of the present invention, where A is the vibration amplitude before correction, the corresponding hysteresis time is t, A' is the vibration amplitude after correction, and the corresponding hysteresis time is t', and A D is an empirical value;

[0031] Figure 2 is the flow chart of the fuel component applicability evaluation method based on the hysteresis time of an embodiment of the present invention.

[0032] Figure 3 is the flow chart of the fuel component applicability evaluation method based on the hysteresis time of another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] The present invention provides a method for evaluating the applicability of fuel components based on the hysteresis time, including the following steps:

[0035] Determine the components and component molar calorific values of the new fuel;

[0036] Conduct a calorific value determination of the new fuel. If the calorific value of the new fuel does not meet the calorific value requirements of the designed fuel, it is considered that the new fuel is not applicable to this combustion engine; if the calorific value of the new fuel meets the calorific value requirements of the designed fuel, then based on the hysteresis time, predict the oscillation performance of the new fuel. If the oscillation amplitude is less than or equal to the allowed oscillation amplitude, it is considered that the oscillation risk of the new fuel is small and it can be used for this combustion engine. If the oscillation amplitude is greater than the allowed oscillation amplitude, it is considered that the new fuel is not applicable to this combustion engine.

[0037] According to a specific implementation scheme of the present invention, conduct a calorific value determination of the new fuel. If the calorific value of the new fuel does not meet the calorific value requirements of the designed fuel, it is considered that the new fuel is not applicable to this combustion engine and the evaluation ends; if the calorific value of the new fuel meets the calorific value requirements of the designed fuel, then predicting the oscillation performance of the new fuel based on the hysteresis time specifically includes:

[0038] Calculate the mixed calorific value of the new fuel according to the molar fractions and calorific values of the components in the new fuel;

[0039] Compare the mixed calorific value of the new fuel with the calorific value requirements of the designed fuel. If the calorific value deviation is within the preset range, it is considered that the new fuel can meet the combustion requirements, and predict the oscillation performance of the new fuel based on the hysteresis time; if the calorific value deviation exceeds the preset range, it is considered that the new fuel is not applicable to this combustion engine.

[0040] According to a specific implementation scheme of the present invention, predicting the oscillation performance of the new fuel based on the hysteresis time includes the following steps:

[0041] Obtain the relationship curve between the hysteresis time t and the oscillation amplitude A of the designed fuel through experimental data and operation data;

[0042] Utilize the influence of hydrogen content and carbon monoxide content on the hysteresis time to correct the relationship curve between the hysteresis time and the oscillation amplitude, and obtain the corrected relationship curve between the hysteresis time and the oscillation amplitude;

[0043] Determine the oscillation amplitude A’ at the designed hysteresis time point after using the new fuel according to the relationship curve between the corrected hysteresis time and the oscillation amplitude.

[0044] According to a specific embodiment of the present invention, the relationship curve between the hysteresis time t and the oscillation amplitude A of the designed fuel is fitted to a trigonometric function curve, defined as A = asin(wt + b) + c, where a, w, b, and c are constant coefficients obtained by fitting experimental data and operating data.

[0045] According to a specific embodiment of the present invention, the relationship curve between the corrected hysteresis time and the oscillation amplitude is A’ = asin(wt’ + b) + c;

[0046] where, t’ = t(1 - r H2 + r CO );

[0047] r H2 is the hydrogen correction coefficient, defined as ;

[0048] r CO is the carbon monoxide correction coefficient, defined as ;

[0049] where, k1, k2, t D , t CO and t H2 are given constants, m H2 is the hydrogen mole fraction, m CO is the carbon monoxide mole fraction.

[0050] According to a specific embodiment of the present invention, it further includes that if the oscillation amplitude is greater than the allowable oscillation amplitude, when it is considered that the new fuel is not applicable to this internal combustion engine, the equivalence ratio and the structure of the burner are improved according to the hydrogen correction coefficient and the carbon monoxide correction coefficient.

[0051] According to a specific embodiment of the present invention, if 1 - r H2 + r CO is less than 1, it indicates that the hysteresis time is shortened, and the length of the premixed section of the burner is increased or the equivalence ratio in the combustion zone is reduced;

[0052] If 1 - r H2 + r CO is greater than 1, it indicates that the hysteresis time is increased, and the length of the premixed section of the burner is reduced or the equivalence ratio in the combustion zone is increased.

[0053] According to a specific embodiment of the present invention, the hysteresis time t of the fuel is obtained by obtaining the heat release signal through a flame detector or a camera, and then comparing the heat release signal with the pressure pulsation signal.

[0054] According to a specific embodiment of the present invention, the oscillation amplitude A is obtained from the pressure pulsation signal.

[0055] According to a specific embodiment of the present invention, the calorific value is calculated according to the GB / T 11062 standard, and the preset range of the calorific value is obtained from the fuel gas standard of the gas turbine.

[0056] Embodiment 1

[0057] As Figure 2 shown, the present invention provides a method for evaluating the applicability of fuel components based on the hysteresis time, including the following steps:

[0058] Determine the components and component molar calorific values of the new fuel;

[0059] Perform a calorific value determination for the new fuel. If the calorific value of the new fuel does not meet the design fuel calorific value requirement, it is considered that the new fuel is not applicable to this gas turbine; if the calorific value of the new fuel meets the design fuel calorific value requirement, then based on the hysteresis time, perform a pre-judgment on the oscillation performance of the new fuel. If the oscillation amplitude is less than or equal to the allowable oscillation amplitude, it is considered that the oscillation risk of the new fuel is small and it can be used for this gas turbine; if the oscillation amplitude is greater than the allowable oscillation amplitude, it is considered that the new fuel is not applicable to this gas turbine.

[0060] Embodiment 2

[0061] As Figure 3 shown, the present invention provides a method for evaluating the applicability of fuel components based on the hysteresis time, including the following steps:

[0062] Determine the components and component molar calorific values of the new fuel;

[0063] Perform a calorific value determination for the new fuel. If the calorific value of the new fuel does not meet the design fuel calorific value requirement, it is considered that the new fuel is not applicable to this gas turbine; if the calorific value of the new fuel meets the design fuel calorific value requirement, then based on the hysteresis time, perform a pre-judgment on the oscillation performance of the new fuel. If the oscillation amplitude is less than or equal to the allowable oscillation amplitude, it is considered that the oscillation risk of the new fuel is small and it can be used for this gas turbine; if the oscillation amplitude is greater than the allowable oscillation amplitude, it is considered that the new fuel is not applicable to this gas turbine. The calorific value is calculated according to the GB / T 11062 standard.

[0064] Furthermore, perform a calorific value determination for the new fuel. If the calorific value of the new fuel does not meet the design fuel calorific value requirement, it is considered that the new fuel is not applicable to this gas turbine and the evaluation ends; if the calorific value of the new fuel meets the design fuel calorific value requirement, then the specific steps for performing a pre-judgment on the oscillation performance of the new fuel based on the hysteresis time include:

[0065] Calculate the mixed calorific value of the new fuel according to the molar fractions and calorific values of the components in the new fuel;

[0066] Compare the calorific value of the new fuel mixture with the calorific value requirement of the designed fuel. If the calorific value deviation is within the preset range, it is considered that the new fuel can meet the combustion requirements, and the oscillation performance of the new fuel is predicted based on the lag time. If the calorific value deviation exceeds the preset range, it is considered that the new fuel is not applicable to this combustion engine. The preset range of the calorific value is obtained from the fuel gas specification of the combustion engine.

[0067] Among them, predicting the oscillation performance of the new fuel based on the lag time includes the following steps:

[0068] Obtain the heat release signal through the flame detector or camera, then compare the heat release signal with the pressure pulsation signal to obtain the lag time t of the fuel, obtain the oscillation amplitude A through the pressure pulsation signal, and then obtain the relationship curve between the lag time t and the oscillation amplitude A of the designed fuel through the regression calculation method. Fit the relationship curve between the lag time t and the oscillation amplitude A of the designed fuel into a trigonometric function relationship curve, as Figure 1 shown, which is the absolute value curve of this relationship curve, where A D is an empirical value, defined as A = asin(wt + b) + c, where a, w, b, and c are constant coefficients obtained by fitting experimental data and operation data.

[0069] The flame propagation speed of hydrogen is fast. With the burner structure unchanged, an increase in the hydrogen content will reduce the fuel lag time t. The flame propagation speed of carbon monoxide is slow, and an increase in the carbon monoxide content will increase the fuel lag time t. Utilize the influence of the hydrogen content and carbon monoxide content on the lag time t to correct the relationship curve between the lag time and the oscillation amplitude, and obtain the corrected relationship curve between the lag time and the oscillation amplitude; the corrected relationship curve between the lag time and the oscillation amplitude is A' = asin(wt' + b) + c;

[0070] where, t' = t(1 - r H2 + r CO );

[0071] r H2 is the hydrogen correction coefficient, defined as ;

[0072] r CO is the carbon monoxide correction coefficient, defined as ;

[0073] where, k1, k2, t D , t CO and t H2 are given constants, m H2 is the hydrogen mole fraction, and m CO is the carbon monoxide mole fraction;

[0074] Determine the oscillation amplitude A’ at the designed hysteresis time point after using the new fuel according to the relationship curve between the corrected hysteresis time and the oscillation amplitude;

[0075] It also includes that if the oscillation amplitude is greater than the allowable oscillation amplitude, it is considered that the new fuel is not applicable to this internal combustion engine. At this time, improve the equivalence ratio and the structure of the burner according to the hydrogen correction coefficient and the carbon monoxide correction coefficient.

[0076] Wherein, if 1 - r H2 + r CO is less than 1, it indicates that the hysteresis time is shortened, increase the length of the premixed section of the burner or reduce the equivalence ratio in the combustion zone;

[0077] If 1 - r H2 + r CO is greater than 1, it indicates that the hysteresis time is increased, reduce the length of the premixed section of the burner or increase the equivalence ratio in the combustion zone.

[0078] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included within the protection scope of the present invention.

Claims

1. A method for evaluating the suitability of fuel components based on hysteresis time, characterized in that: The steps include: Determine the composition and molar calorific value of the new fuel; The calorific value of the new fuel is determined. If the calorific value of the new fuel does not meet the design fuel calorific value requirement, it is considered that the new fuel is not suitable for this engine. If the calorific value of the new fuel meets the design fuel calorific value requirement, the oscillation performance of the new fuel is predicted based on the hysteresis time. If the oscillation amplitude is less than or equal to the allowed oscillation amplitude, it is considered that the oscillation risk of the new fuel is small and can be used for this engine. If the oscillation amplitude is greater than the allowed oscillation amplitude, it is considered that the new fuel is not suitable for this engine. Among them, the calorific value of the new fuel is determined. If the calorific value of the new fuel does not meet the design fuel calorific value requirement, it is considered that the new fuel is not suitable for the gas engine and the evaluation is terminated; if the calorific value of the new fuel meets the design fuel calorific value requirement, the oscillation performance prediction of the new fuel based on the hysteresis time specifically includes: According to the mole fraction and calorific value of each component in the new fuel, the mixed calorific value of the new fuel is calculated; Compare the mixed calorific value of the new fuel with the calorific value requirement of the designed fuel. If the calorific value deviation is within the preset range, it is considered that the new fuel can meet the combustion requirements, and the oscillation performance of the new fuel is predicted based on the hysteresis time; if the calorific value deviation exceeds the preset range, it is considered that the new fuel is not suitable for this gas engine; The prediction of the oscillation performance of the new fuel based on the hysteresis time includes the following steps: The relationship curve between the hysteresis time t and the oscillation amplitude A of the designed fuel is obtained through experimental data and operation data; The relationship curve between the hysteresis time and the oscillation amplitude is corrected by using the influence of the hydrogen content and the carbon monoxide content on the hysteresis time, so as to obtain the corrected relationship curve between the hysteresis time and the oscillation amplitude; The oscillation amplitude A' at the designed hysteresis time point after using the new fuel is determined based on the relationship curve between the corrected hysteresis time and the oscillation amplitude.

2. The fuel composition suitability evaluation method based on hysteresis time according to claim 1, characterized in that: The relationship curve between the hysteresis time t and the oscillation amplitude A of the design fuel is fitted into a trigonometric function relationship curve, which is defined as A=asin(wt+b)+c, where a, w, b, and c are constant coefficients obtained by fitting the experimental data and operating data.

3. The fuel composition suitability evaluation method based on hysteresis time according to claim 2, characterized in that: The relationship curve between the corrected hysteresis time and the oscillation amplitude is A'=asin(wt'+b)+c; Where t'=t(1-r H2 +r CO ); r H2 is the hydrogen correction factor, defined as ; r CO is the carbon monoxide correction factor, defined as ; Among them, k1, k2, t D ,t CO and t H2 is a given constant, m H2 is the mole fraction of hydrogen, m CO is the mole fraction of carbon monoxide.

4. The method for evaluating the suitability of fuel components based on hysteresis time according to claim 3, characterized in that: It also includes that if the oscillation amplitude is greater than the permissible oscillation amplitude, the new fuel is considered unsuitable for the engine, and the equivalence ratio and the structure of the burner are improved according to the hydrogen correction factor and the carbon monoxide correction factor, specifically: If 1-r H2 +r CO If it is less than 1, it means that the delay time is shortened, the length of the premixing section of the burner is increased, or the equivalence ratio of the combustion area is reduced; If 1-r H2 +r CO If it is greater than 1, it means that the delay time increases, the length of the burner premixing section is reduced, or the equivalence ratio of the combustion area is increased.

5. The fuel composition suitability evaluation method based on hysteresis time according to claim 2, characterized in that: The fuel delay time t is obtained by obtaining a heat release signal through a fire detector or a camera, and then the heat release signal is compared with the pressure pulsation signal.

6. The method for evaluating the suitability of fuel components based on hysteresis time according to claim 1, characterized in that: The oscillation amplitude A is obtained through the pressure pulsation signal.

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