JP5824254B2 - Gas engine gas flow measuring device and method - Google Patents

Description

  The present invention relates to a gas flow rate measuring apparatus and method for a gas engine that measures the flow rate of fuel gas supplied to a gas engine.

  In recent years, in power plants and the like, technological development for high-efficiency power generation is accelerating, and a high-efficiency gas engine as a driving source is also demanded. A highly accurate flow meter is indispensable for measuring the fuel consumption of a gas engine, and a positive displacement flow meter that is not affected by electrical noise or the like is generally used. However, the positive displacement flowmeter is susceptible to the pulsation of fuel gas generated by a pressure regulating valve or the like provided in the fuel gas supply line to the gas engine, and there is a problem in measurement accuracy. Therefore, in Patent Document 1, a buffer means is provided in the middle of the pipe connecting the pressure regulating valve and the flow meter to reduce the influence of pulsation caused by the pressure regulating valve, thereby improving the flow rate measurement accuracy.

Japanese Patent No. 3259820

  However, the buffer means of Patent Document 1 has a fixed mesh structure, and when the pressure loss is large, the influence cannot be ignored. For example, if the pressure loss in the mesh structure is large, the loss must be compensated by increasing the boosting capacity of the gas booster, which increases the energy consumption of the entire facility, resulting in the energy efficiency of the power plant. Will be reduced.

  Accordingly, an object of the present invention is to achieve both improvement in fuel gas flow rate measurement accuracy and improvement in energy efficiency.

  The present invention has been made in view of the above circumstances, and a gas flow rate measuring device for a gas engine according to the present invention is a gas flow rate measuring device for a gas engine that measures the flow rate of fuel gas supplied to the gas engine. A booster for boosting the fuel gas supplied from the fuel gas supply source; a first flow rate measuring unit for measuring the flow rate of the fuel gas boosted by the booster; and a downstream side of the first flow rate measurer. A pressure adjusting means for adjusting a supply pressure of the fuel gas supplied to the gas engine, and a throttle portion provided between the first flow rate measuring means and the pressure adjusting means for suppressing fuel gas pulsation And the buffer means is configured to variably adjust the opening of the throttle portion.

  According to the above configuration, the opening degree of the throttle part of the buffer means can be variably adjusted, so that the throttle part opening degree is set so that pressure loss in the throttle part does not become excessive while reducing the influence of pulsation by the throttle part. It can be set easily. That is, it is possible to suppress the pressure loss in the buffering means while making it possible to measure the flow rate with high accuracy, and it becomes unnecessary to increase the pressure of the fuel gas by the pressure increasing means. Therefore, it is possible to achieve both improvement in fuel gas flow rate measurement accuracy and improvement in energy efficiency.

  The opening degree of the throttle part is a correlation between the flow amplitude value of the fuel gas depending on the opening degree of the throttle part and the integrated flow rate value per predetermined time of the fuel gas measured by the first flow rate measuring means. May be set using the rate of change of the integrated flow rate value.

  According to the above configuration, the throttle unit refers to the rate of change of the integrated flow value (the amount of change of the integrated flow value when the flow amplitude value changes by a predetermined amount) from the correlation between the flow amplitude value and the integrated flow value. By setting the degree of opening, it is possible to suitably set the degree of opening of the throttle part so that the pressure loss in the throttle part does not become excessive while reducing the influence of pulsation by the throttle part.

  In the correlation, the opening degree of the throttle portion may be set in a range where the rate of change of the integrated flow rate value is less than a predetermined value and the flow rate amplitude value is greater than or equal to a predetermined value.

  According to the above configuration, the flow rate amplitude value in the range where the rate of change of the integrated flow rate value is small (i.e., the opening of the throttle portion) is selected, and while realizing highly accurate flow rate measurement with reduced influence of pulsation, It is possible to prevent an increase in pressure loss due to an excessively small flow amplitude value, and it is possible to set a good throttle opening degree in terms of both flow measurement accuracy and energy efficiency.

  The opening at the largest flow amplitude value among the flow amplitude values at which the rate of change of the integrated flow value is less than a predetermined value in the correlation may be set as the opening of the throttle portion.

  According to the above-described configuration, it is possible to obtain the throttle opening with the least pressure loss within a range where the flow rate measurement accuracy is good, and it is possible to set the optimum throttle opening with the necessary minimum pulsation buffer.

  The buffer means may be configured to variably adjust the opening of the throttle portion.

  According to the above configuration, the throttle opening can be easily adjusted, and the opening can be easily readjusted even when the fuel gas supply pressure changes after setting the throttle opening to the optimum value. it can.

  The apparatus may further include a second flow rate measuring unit that is provided in series with the first flow rate measuring unit and that calculates a flow amplitude value of the fuel gas.

  According to the said structure, the failure of a flow measurement means can be grasped | ascertained at an early stage by using two flow measurement means. Further, when a mass flow meter is used as the second flow rate measuring means, the flow rate amplitude can be easily calculated, and the optimum value of the aperture of the throttle can be set with higher accuracy.

  The gas flow rate measuring method for a gas engine according to the present invention is a gas flow rate measuring method for a gas engine for measuring a flow rate of a fuel gas supplied to the gas engine, and boosts the fuel gas supplied from a fuel gas supply source. A pressure increase step, a first flow rate measurement step for measuring the flow rate of the boosted fuel gas, a pressure adjustment step for adjusting the supply pressure of the fuel gas supplied to the gas engine, and suppression of fuel gas pulsation by throttling A buffering step, and an opening degree setting step of variably adjusting and setting the opening degree of the throttle.

  According to the above method, by adjusting the throttle opening, it is possible to easily set the throttle opening so that the pressure loss in the throttle does not become excessive while reducing the influence of pulsation by the throttle. That is, it is possible to suppress the pressure loss in the buffering process while making it possible to measure the flow rate with high accuracy, and it is not necessary to increase the pressure of the fuel gas unnecessarily in the pressure increasing process. Therefore, it is possible to achieve both improvement in fuel gas flow rate measurement accuracy and improvement in energy efficiency.

  An amplitude calculating step of calculating a flow amplitude value of the fuel gas according to the opening of the throttle, and an integrated flow calculating step of calculating an integrated flow value per predetermined time of the fuel gas according to the opening of the throttle, respectively. In the opening degree setting step, the opening degree of the throttle may be set using the rate of change of the integrated flow value in the correlation between the flow rate amplitude value and the integrated flow value. .

  According to the above method, the change rate of the integrated flow value (the change amount of the integrated flow value when the flow amplitude value changes by a predetermined amount) is referred to from the correlation between the flow amplitude value and the integrated flow value. By setting the opening, it is possible to suitably set the opening of the throttle portion so that the pressure loss in the throttle does not become excessive while reducing the influence of pulsation by the throttle.

  In the opening degree setting step, the opening degree of the throttle portion may be set in a range where the rate of change of the integrated flow rate value is less than a predetermined value and the flow rate amplitude value is not less than a predetermined value in the correlation.

  According to the method, the flow rate amplitude value (that is, the opening degree of the throttle) in the range where the change rate of the integrated flow rate value is small is selected, and the flow rate is reduced while realizing the highly accurate flow rate measurement with reduced influence of pulsation. It is possible to prevent the amplitude value from becoming too small and increase the pressure loss, and it is possible to set a favorable throttle opening degree in terms of both flow measurement accuracy and energy efficiency.

In the opening setting step, the opening at the largest flow amplitude value among the flow amplitude values at which the rate of change of the integrated flow value is less than a predetermined value in the correlation is set as the opening of the throttle.
According to the above method, it is possible to obtain a throttle opening with the least pressure loss within a range in which the flow rate measurement accuracy is good, and it is possible to set an optimum throttle opening.

  In the amplitude calculating step and the integrated flow rate calculating step, the flow rate amplitude value and the integrated flow value at each opening are calculated by changing the opening of the throttle from large to small, and in the opening setting step, the amplitude is calculated. Immediately before the rate of change of the integrated flow rate value is less than or equal to the predetermined value while changing the opening of the throttle from large to small in the calculation step and the integrated flow rate calculation step Or an opening in the vicinity thereof may be set as the opening of the throttle.

  According to the above method, the rate of change of the integrated flow rate value decreases as the aperture of the throttle is changed from large to small, and the opening when the rate of change becomes greater than a predetermined value and less than a predetermined value. Therefore, when setting the throttle opening, it is not necessary to change the throttle opening in the whole opening range, and the time required for opening setting is shortened. be able to. In addition, the flow rate is not stable when the throttle is low, but by changing the throttle opening from large to small, the flow amplitude value and integrated flow value can be calculated while the flow rate is stable. Therefore, it is possible to set the optimum throttle opening with high accuracy.

  As is apparent from the above description, according to the present invention, it is possible to achieve both improvement in fuel gas flow rate measurement accuracy and improvement in energy efficiency.

It is a block diagram which shows the power plant provided with the gas flow measuring device of the gas engine which concerns on embodiment of this invention. It is a graph showing the flow volume amplitude value of the fuel gas supplied to the gas engine shown in FIG. 3 is a graph showing a correlation between an integrated flow rate value per unit time of fuel gas supplied to the gas engine shown in FIG. 1 and a flow rate amplitude value of FIG. It is a flowchart explaining the procedure which determines the aperture opening degree of the shock absorber shown in FIG. 5 is a graph showing a correlation between an integrated flow rate value per unit time and a flow amplitude value measured during the procedure of FIG.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram showing a power plant 1 including a gas flow rate measuring device 3 for a gas engine 2 according to an embodiment of the present invention. As shown in FIG. 1, the gas engine 2 is a reciprocating multi-cylinder four-stroke engine that uses fuel gas such as natural gas or city gas as a main fuel, and drives a generator (not shown) of the power plant 1. It is used as a prime mover. A piston 5 is inserted into the cylinder 4 so as to be able to reciprocate. The piston 5 is connected to a crankshaft (not shown) as an output shaft. A space above the piston 5 in the cylinder 4 is a main combustion chamber 6. An air supply port 8 is connected to the main combustion chamber 6 via an air supply valve 7, and an exhaust port 10 is connected via an exhaust valve 9. A main fuel gas supply valve 11 for injecting fuel gas is provided in the air supply port 8. A sub-combustion chamber 12 is adjacent to the main combustion chamber 6 via a partition wall 13. The auxiliary combustion chamber 12 communicates with the main combustion chamber 6 through a communication hole 14 formed in the partition wall 13. The auxiliary combustion chamber 12 is provided with an auxiliary fuel gas supply valve 15 for injecting fuel gas and an ignition plug 16 for burning the air-fuel mixture.

  According to the gas engine 2, in the supply stroke, the main combustion chamber 6 is supplied with an air-fuel mixture including air and fuel gas injected by the main fuel gas supply valve 11 from the supply port 8, and is supplied to the sub-combustion chamber 12. Is supplied with an air-fuel mixture containing fuel gas injected by the auxiliary fuel gas supply valve 15. After the air-fuel mixture in the main combustion chamber 6 and the sub-combustion chamber 12 is compressed in the compression stroke, the spark plug 16 operates at a predetermined timing to ignite the air-fuel mixture in the sub-combustion chamber 12. The flame generated in the sub-combustion chamber 12 propagates into the main combustion chamber 6 through the communication hole 14, and the air-fuel mixture in the main combustion chamber 6 is ignited. As a result, the piston 5 moves downward to perform the expansion stroke. In the exhaust stroke, the gas in the main combustion chamber 6 is discharged to the outside through the exhaust port 10.

  The power plant 1 is provided with a main controller 17 that controls the gas engine 2 so that the power generator generates power at a constant output. The main controller 17 is connected to a gas valve controller 18 that drives the main fuel gas supply valve 11 and the auxiliary fuel gas supply valve 15. The main controller 17 is connected to a spark plug driver 19 that drives the spark plug 16. The main controller 17 has various input information such as the output of a generator (not shown) driven by the gas engine 2, the pressure and temperature of the supply air supplied to the supply port 8, and the crank angle of the gas engine 2. Input from the sensor. The main control device 17 outputs a command signal to the gas valve control device 18 and the spark plug driver 19 based on the input information, and controls the operation of the fuel gas supply valves 11 and 15 and the spark plug 16.

  The power plant 1 is provided with a gas flow rate measuring device 3 that measures the flow rate of the fuel gas supplied to the gas engine 2. The gas flow rate measuring device 3 includes a fuel gas supply pipe 20 that supplies fuel gas to the gas engine 2. The fuel gas supply pipe 20 is a fuel gas common supply pipe provided with a gas booster 24 (pressure increase means) for increasing the pressure of fuel gas supplied from an external fuel gas supply source (not shown) to a set pressure. The fuel gas supply pipe 20 branches into a main fuel gas supply pipe 22 and a sub fuel gas supply pipe 23 on the downstream side of the fuel gas common supply pipe 21. The main fuel gas supply pipe 22 is provided with a main pressure adjustment valve 25 (pressure adjustment means) for adjusting the supply pressure of the fuel gas supplied to the fuel gas supply valve 11. The auxiliary fuel gas supply pipe 23 is provided with an auxiliary pressure adjusting valve 26 (pressure adjusting means) that adjusts the supply pressure supplied to the auxiliary fuel gas supply valve 15.

  The fuel gas common supply pipe 21 is provided with a positive displacement flow meter 27 (first flow rate measuring means) for measuring the flow rate of the fuel gas boosted to the set pressure by the gas booster 24. The gas flow rate measured by the positive displacement flow meter 27 when the power plant is in operation is used to calculate fuel consumption (power generation efficiency). The positive displacement flow meter 27 is a flow meter that measures a gas flow rate from the number of rotations of a rotor such as a gear that rotates in proportion to the passing volume of fuel gas flowing through the common fuel gas supply pipe 21. Therefore, the positive displacement flowmeter 27 has a low failure probability and is not affected by electrical noise even if the usage environment during power plant operation is poor.

  The fuel gas common supply pipe 21 is provided with a variable throttle valve 28 (buffer means) at a position between the positive displacement flow meter 27 and the pressure regulating valves 25 and 26. The variable throttle valve 28 is a valve having a throttle portion whose opening degree can be adjusted, and is used as a buffer device for suppressing pulsation of fuel gas in the fuel gas common supply pipe 21 provided with the positive displacement flow meter 27. . The fuel gas common supply pipe 21 is provided with a mass flow meter 29 (second flow rate measuring means) for calculating the flow amplitude value of the fuel gas in series immediately upstream of the positive displacement flow meter 27. Although the mass flow meter 29 can easily calculate the flow amplitude value by outputting the instantaneous flow rate as a pulse, it may be affected by sensor failure or noise depending on the use environment during operation of the power plant.

  FIG. 2 is a graph showing the flow amplitude value of the fuel gas supplied to the gas engine 2 shown in FIG. As shown in FIG. 2, the instantaneous flow rate measured by the mass flow meter 29 periodically increases and decreases due to the opening and closing of the fuel gas supply valves 11 and 15 and the effects of the springs of the pressure adjustment valves 25 and 26, etc. The fuel gas flowing through the supply pipe 21 pulsates. The flow amplitude value of the fuel gas depends on the opening of the variable throttle valve 28. Specifically, the flow amplitude value of the fuel gas increases when the opening degree of the variable throttle valve 28 is large (the flow passage cross section of the throttle part is large), and the opening degree of the variable throttle valve 28 is small (of the throttle part). It becomes smaller when the flow path cross section is small. That is, when the opening of the variable throttle valve 28 is reduced, the pulsation buffering effect is increased.

  FIG. 3 is a graph showing the correlation between the integrated flow rate value per unit time of the fuel gas supplied to the gas engine 2 shown in FIG. 1 and the flow rate amplitude value of FIG. As shown in FIG. 3, since the flow amplitude value increases by increasing the opening of the variable throttle valve 28, the integrated flow rate value measured by the positive displacement flow meter 27 increases in a quadratic curve. Will be. However, since the pressure of the fuel gas is adjusted by the gas booster 24 and the pressure adjustment valves 25 and 26, the actual integrated flow rate value should be substantially constant even if the opening of the variable throttle valve 28 changes. When actually measured by the mass flow meter 29, the integrated flow value becomes substantially constant (however, when the opening of the variable throttle valve 28 is extremely small, the flow of fuel gas is hindered and the actual integrated flow value also decreases. ). That is, as the flow amplitude value increases, the measurement accuracy of the positive displacement flow meter 27 decreases, and more integrated flow values per unit time are measured than actually. This is because the inertial force acts on the rotor of the positive displacement flow meter 27 due to the pulsation of the flow of the fuel gas, so that the rotor of the positive displacement flow meter 27 rotates more than the passing volume of the fuel gas. Because it ends up. Therefore, as the flow amplitude value increases, the measurement accuracy of the positive displacement flow meter 27 deteriorates, and as the flow amplitude value decreases, the measurement accuracy of the positive displacement flow meter 27 improves.

  However, if the opening of the variable throttle valve 28 is reduced too much to reduce the flow amplitude value, the pressure loss at the variable throttle valve 28 increases. If the pressure loss at the variable throttle valve 28 is large, the loss must be compensated by increasing the pressure boosting capacity of the gas booster 24. Therefore, the energy consumption of the entire power plant 1 increases, resulting in power generation. The energy efficiency of the plant 1 will fall.

  Here, focusing on the tendency of the graph of FIG. 3, the integrated flow rate value measured by the positive displacement flow meter 27 does not increase in proportion to the increase in the flow rate amplitude value. In the range where the flow amplitude value is small, the rate of increase of the integrated flow value per unit time measured by the positive displacement flow meter 27 is small, and in the range where the flow amplitude value is large, per unit time measured by the positive displacement flow meter 27. The increase rate of the integrated flow rate value becomes larger. Therefore, the opening of the variable throttle valve 28 when the flow amplitude value is as large as possible within the range in which the increase rate of the integrated flow value per unit time measured by the positive displacement flow meter 27 is small is the final set opening. If it does so, the optimal opening degree can be obtained in terms of both flow measurement accuracy and energy efficiency. Therefore, in the gas flow rate measuring device 3, the change in the accumulated flow value in the correlation between the flow amplitude value calculated from the mass flow meter 29 and the accumulated flow value per unit time measured by the positive displacement flow meter 27. The opening of the variable throttle valve 28 when the rate is less than the predetermined value and the flow amplitude value is greater than or equal to the predetermined value is set to the opening during normal operation (during power generation). Note that a flow rate amplitude value can also be measured by a positive displacement flow meter with a pulse output function.

  FIG. 4 is a flowchart for explaining the procedure for determining the throttle opening of the shock absorber shown in FIG. FIG. 5 is a graph showing the correlation between the integrated flow rate value per unit time measured during the procedure of FIG. 4 and the flow rate amplitude value. The procedure of FIG. 4 is performed in a state in which the fuel gas supplied to the gas engine 2 is boosted to a predetermined pressure by the gas booster 24 and the gas engine 2 is trial run. As shown in FIGS. 4 and 5, first, the opening of the variable throttle valve 28 is set to the initial opening (step S1). The initial opening is calculated by changing the opening of the variable throttle valve 28 from large to small in the subsequent process and calculating the flow amplitude value and integrated flow value at each opening. The opening is determined to be larger than the opening that is expected to exist.

  Next, 1 is substituted for the number of measurements n (step S2). Then, the mass flow meter 29 measures the nth (n = 1) flow amplitude value A (n) (step S3), and the positive displacement flowmeter 27 measures the nth (n = 1) unit time. The integrated flow value F (n) is measured (step S4). The integrated flow rate value F (n) at each measurement point is an average value of values measured for 5 minutes or more. Next, n + 1 is substituted for the number of measurements n and n is incremented by 1 (step S5), and the opening of the variable throttle valve 28 is reduced (step S6). At this time, a value obtained by subtracting a value corresponding to a predetermined percentage (for example, 5%) of the current integrated flow value F (n-1) from the current flow amplitude value A (n-1) is the next flow amplitude value. The opening degree of the variable throttle valve 28 is determined so as to be A (n). At this time, the difference between the n-th opening and the (n + 1) -th opening is reduced as n increases, so that the working time can be shortened while ensuring the optimum throttle opening determination accuracy. it can.

  Then, the n-th (n = 2) flow amplitude value A (n) is measured by the mass flow meter 29 (step S7), and the n-th (n = 2) unit time per unit time is measured by the positive displacement flow meter 27. The integrated flow value F (n) is measured (step S8). In FIG. 5, the measurement point consisting of the flow amplitude value and the integrated flow value measured at the (n-1) th time (n = 2), and the flow amplitude value and the integrated value measured at the nth time (n = 2). It is determined whether or not the rate of change of the integrated flow rate value with respect to the measurement point consisting of the flow rate value is less than a predetermined value α. Specifically, it is determined whether or not Formula 1 is satisfied (step S9). The predetermined value α is a rate of change near the optimum point in FIG. 3 that has been examined in advance, and is a value selected from a range of 0.05 to 0.2 (for example, 0.1) in this example. .

[Formula 1]
{F (n-1) -F (n)} / {A (n-1) -A (n)} <α
If Equation 1 is not satisfied in step S9, the process returns to step S5 and is repeated. When Expression 1 is satisfied in Step S9, the opening degree of the variable throttle valve 28 is determined to be the opening degree at the (n-1) th time (Step S10). In the example of FIG. 5, Formula 1 is satisfied when the opening of the variable throttle valve 28 is the fifth opening, so the fourth opening immediately before or the opening in the vicinity thereof is set to the variable throttle valve 28. Set to the optimal opening.

  According to the above, the rate of change of the integrated flow value is referred to from the correlation between the flow rate amplitude value and the integrated flow value, and the largest flow amplitude value among the flow amplitude values at which the change rate is less than the predetermined value α. Is set to the opening of the variable throttle valve 28. Thereby, while realizing highly accurate flow measurement with reduced influence of pulsation, it is prevented that the flow amplitude value becomes too small and the pressure loss increases, and the gas booster 24 wastes fuel gas. There is no need to boost the voltage. Therefore, it is possible to achieve both improvement in fuel gas flow measurement accuracy and improvement in energy efficiency by optimizing the minimum pulsation buffering degree necessary for ensuring gas flow measurement accuracy.

  Further, the opening degree of the variable throttle valve 28 is changed from large to small, and the opening degree when the rate of change of the integrated flow rate value is greater than or equal to the predetermined value α and less than the predetermined value α is set at or near the opening degree. Since the optimum opening of the variable throttle valve 28 is set, it is not necessary to change the opening of the variable throttle valve 28 in the entire opening range when setting the opening of the variable throttle valve 28, and the optimum opening is determined. The work time required for this can be shortened. In addition, the flow rate is not stable when the variable throttle valve 28 is at a very low opening, but by changing the opening of the variable throttle valve 28 from large to small, the flow amplitude value and The integrated flow rate value can be calculated, and the optimum throttle opening can be set with high accuracy.

  Furthermore, since the variable throttle valve 28 is used as a shock absorber, it is easy to adjust the throttle opening, and the opening is also easy when the fuel gas supply pressure changes after the throttle opening is set to the optimum value. Can be readjusted. Further, since the mass flow meter 29 is provided in series with the positive displacement flow meter 27, the flow amplitude value can be easily and accurately calculated by the mass flow meter 29, and the failure of the positive displacement flow meter 27 can be grasped at an early stage. Can do. Moreover, the mass flow meter 29 is mainly used when determining the throttle opening before the power plant 1 is actually operated, and the positive displacement flow meter 27 is used for fuel consumption measurement. Fuel consumption can be measured with high accuracy.

  In the present embodiment, when Expression 1 is satisfied in Step S9, the opening degree of the variable throttle valve 28 is immediately determined as the opening degree at the (n-1) th time (Step S10). The accumulated flow value per unit time measured with the positive displacement flow meter 27 at the first time is a predetermined error from the accumulated flow value per unit time measured with the mass flow meter 29 at the (n-1) th time. When the condition of being in the range (for example, ± 2%) is also satisfied, the process may proceed from step S9 to step S10. In this embodiment, the integrated flow value is measured by the positive displacement flow meter 27 and the flow amplitude value is measured by the mass flow meter 29. However, the mass flow meter is abolished and the flow amplitude is obtained by the positive displacement flow meter with pulse output. Both the value and the integrated flow value may be measured. Further, instead of the variable throttle valve 28, a plurality of fixed throttle members having different throttle openings may be prepared, and a throttle member having an optimum throttle opening may be selected and installed. The gas engine 2 may be provided with a supercharger. Further, the present invention is not limited to the above-described embodiment, and the configuration can be changed, added, or deleted without departing from the spirit of the present invention.

  As described above, the gas flow rate measuring device and method for a gas engine according to the present invention has an excellent effect that makes it possible to achieve both improvement in fuel gas flow rate measurement accuracy and improvement in energy efficiency. It is beneficial to apply widely to gas engine power plants that can demonstrate the significance of the effect.

DESCRIPTION OF SYMBOLS 1 Power plant 2 Gas engine 3 Gas flow measuring device 20 Fuel gas supply pipe 24 Gas pressure | voltage riser (pressure | voltage riser)
25, 26 Main pressure regulating valve (pressure regulating means)
27 Volumetric flow meter (first flow rate measuring means)
28 Variable throttle valve (buffer means)
29 Mass flow meter (second flow rate measuring means)

Claims (8)

A gas flow rate measuring device for a gas engine for measuring a flow rate of fuel gas supplied to a gas engine,
Boosting means for boosting the fuel gas supplied from the fuel gas supply source;
First flow rate measuring means for measuring the flow rate of the fuel gas boosted by the boosting means;
Pressure adjusting means provided on the downstream side of the first flow rate measuring means for adjusting the supply pressure of the fuel gas supplied to the gas engine;
A buffer unit provided between the first flow rate measuring unit and the pressure adjusting unit, and having a throttle part for suppressing pulsation of fuel gas;
The buffer means is configured to variably adjust the opening of the throttle portion ,
The opening degree of the throttle part is a correlation between the flow amplitude value of the fuel gas depending on the opening degree of the throttle part and the integrated flow rate value per predetermined time of the fuel gas measured by the first flow rate measuring means. wherein Ru is set by using the rate of change of the integrated flow rate value at a gas flow rate measuring device for a gas engine. 2. The gas engine according to claim 1 , wherein, in the correlation, the degree of change of the integrated flow rate value is less than a predetermined value and the opening of the throttle unit is set in a range where the flow rate amplitude value is equal to or greater than a predetermined value. Gas flow measuring device. The rate of change of the integrated flow rate value in correlation opening of the largest flow rate amplitude value of said flow rate amplitude value is less than the predetermined value is set to an opening degree of the throttle portion, to claim 1 or 2 A gas flow measuring device for the gas engine as described. A gas flow rate measuring device for a gas engine for measuring a flow rate of fuel gas supplied to a gas engine,
Boosting means for boosting the fuel gas supplied from the fuel gas supply source;
First flow rate measuring means for measuring the flow rate of the fuel gas boosted by the boosting means;
Pressure adjusting means provided on the downstream side of the first flow rate measuring means for adjusting the supply pressure of the fuel gas supplied to the gas engine;
A buffer means provided between the first flow rate measuring means and the pressure adjusting means, and having a throttle part for suppressing pulsation of fuel gas;
Provided in series with the first flow measuring means comprises a second flow rate measuring means for calculating the flow rate amplitude value of the fuel gas, and
Said buffer means, an opening degree of the throttle portion is configured to be variably adjusted, the gas flow rate measuring device of the gas engine. A gas flow rate measuring method for a gas engine for measuring a flow rate of fuel gas supplied to a gas engine,
A boosting step of boosting the fuel gas supplied from the fuel gas supply source;
A first flow rate measuring step for measuring a flow rate of the boosted fuel gas;
A pressure adjusting step for adjusting the supply pressure of the fuel gas supplied to the gas engine;
A buffering process that suppresses fuel gas pulsation by means of a restriction;
An amplitude calculating step for calculating the flow amplitude value of the fuel gas according to the opening of the throttle;
An integrated flow rate calculating step for calculating an integrated flow rate value per predetermined time of the fuel gas according to the opening of the throttle;
An opening setting step of variably adjusting and setting the opening of the throttle ,
In the opening degree setting step, a gas flow rate measuring method for a gas engine, wherein the opening degree of the throttle is set using a rate of change of the integrated flow value in a correlation between the flow amplitude value and the integrated flow value. . In the opening degree setting step, the rate of change of the integrated flow rate value is less than the predetermined value and the flow rate amplitude value sets the aperture size of the diaphragm the range is not less than a predetermined value in the correlation to claim 5 The gas flow rate measuring method of the described gas engine. In the opening degree setting step, the opening degree at the largest flow amplitude value among the flow amplitude values at which the change rate of the integrated flow value is less than a predetermined value in the correlation is set as the opening degree of the throttle. Item 7. A gas flow rate measuring method for a gas engine according to Item 5 or 6 . In the amplitude calculating step and the integrated flow rate calculating step, the flow rate amplitude value and the integrated flow value at each opening are calculated by changing the opening of the throttle from large to small,
Wherein the opening degree setting step, wherein the aperture size of the diaphragm the amplitude calculating step and the integrated flow rate calculation step among going to change to large to small, the integrated flow rate value of the change rate of Tokoro value α or more or al set to an opening or aperture size of the diaphragm the the vicinity of the opening just before when it becomes less than Tokoro value alpha, the gas flow rate measuring method for a gas engine according to claim 5.

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