JP7162831B2 - Controllers, control systems and programs - Google Patents

Description

The present invention relates to control devices, control systems, and programs.

In recent years, due to growing interest in environmental issues, attention has been focused on natural gas, which enables low-pollution combustion. It is known that natural gas has a lower carbon/hydrogen ratio than petroleum or coal, and emits less carbon dioxide when 1 mol of natural gas is burned. It is also known that the amount of NOx (nitrogen oxides) and SOx (sulfur oxides) emitted during combustion is small because N and S components are removed when natural gas is liquefied during transportation. .

Natural gas is a mixture composed mainly of methane, but also hydrocarbons such as ethane and propane. It is known that the ratio of each component varies depending on the production area. The calorific value of natural gas is determined by the abundance ratio of each component. Therefore, when using natural gas from different production areas, the amount of heat generated will also be different.

Natural gas is usually used in a state of being liquefied and stored in a tank or the like. When the amount of liquefied natural gas in the tank decreases and part of the liquefied natural gas evaporates, methane, which has a low specific gravity, tends to exist more in the upper part of the tank, and propane, which has a higher specific gravity, tends to exist in the lower part. be. When the natural gas is discharged from such a tank, the convection generated in the vaporized natural gas becomes significant when the amount of liquefied natural gas in the tank is reduced. When the natural gas convects inside the tank in this manner, the composition of the natural gas may change periodically. In that case, the calorific value of the natural gas may change periodically as the composition ratio of the natural gas changes. As a result, it is assumed that the amount of heat will change abruptly, causing the flame to lengthen or cause a misfire.
A combustion control method capable of suppressing periodic fluctuations in the heat quantity of natural gas in a continuously operating combustor is known (Patent Document 1).

Japanese Unexamined Patent Application Publication No. 2018-31499

The composition of the components of the gas mixture used for combustion may be unknown. For example, when natural gas is stored in different tanks and used by switching from one tank to the other, the natural gas stored in each tank is mixed with natural gas from different production areas. and may differ in fuel composition. Therefore, the fuel composition of natural gas may change as the tank is switched. As a result, the fuel composition of natural gas changed, and the fuel composition became unknown, and there were cases where stable combustion was not possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a control device, a control system, and a program capable of stably burning a mixed gas whose component composition is unknown.

The present invention has been made to solve the above problems, and one aspect of the present invention is to provide a constant total flow rate of a mixed gas whose component composition is unknown and air mixed with the mixed gas, and a flow rate calculation unit that calculates a gas flow rate of the mixed gas and an air flow rate of the air based on a component ratio of the mixed gas when the equivalence ratio between the mixed gas and the air is constant; and A gas flow control unit that controls the flow rate of the mixed gas flowing through the gas pipe based on the gas flow rate calculated by the calculation unit; and a measurement unit that measures the density of the mixed gas indicating the component ratio of the mixed gas. A gas that mixes the mixed gas supplied by the gas pipe and the air supplied by the air pipe at a connection portion between the gas pipe and the air pipe from a measurement position on the route of the gas pipe arranged. a control comprising an air flow rate control section that controls the flow rate of the air flowing through the air pipe based on the delay time corresponding to the distance to the air mixing section and the air flow rate calculated by the flow rate calculation section; It is a device.

In one aspect of the present invention, the control device further includes a component ratio calculator that calculates a component ratio of the mixed gas based on the density at the measurement position, and the flow rate calculator calculates the component A gas flow rate of the mixed gas and an air flow rate of the air are calculated based on the component ratio of the mixed gas indicated by the density calculated by the ratio calculation unit.

Further, according to one aspect of the present invention, in the control device described above, the gas flow rate adjustment valve controlled by the gas flow rate control unit is disposed downstream of the measurement position in the gas pipe, and the air flow rate control unit and controlling the air flow rate of the air based on the transmission time according to the distance from the measurement position to the gas flow rate control valve , the delay time, and the air flow rate calculated by the flow rate calculator .

In one aspect of the present invention, the control device further includes a delay time calculation unit that calculates the delay time based on the density of the mixed gas and the distance from the measurement position to the gas-air mixing unit. Prepare.

Further, one aspect of the present invention includes the control device described above, a gas flow rate adjustment valve arranged on the route of the gas pipe for adjusting the flow rate of the mixed gas flowing through the gas pipe, and on the route of the air pipe and an air flow control valve arranged in the air pipe for adjusting the flow rate of the air flowing through the air pipe.

Further, according to one aspect of the present invention, a computer is provided with a constant total flow rate of a mixed gas whose component composition is unknown and air mixed with the mixed gas, and a constant equivalence ratio between the mixed gas and the air. a flow rate calculation step of calculating the gas flow rate of the mixed gas and the air flow rate of the air based on the component ratio of the mixed gas, and based on the gas flow rate calculated in the flow rate calculation step a gas flow rate control step of controlling the flow rate of the mixed gas flowing through the gas pipe; and measurement on the route of the gas pipe in which a measurement unit for measuring the density of the mixed gas indicating the component ratio of the mixed gas is arranged. a delay time according to the distance from a position to a gas-air mixing section that mixes the mixed gas supplied by the gas pipe and the air supplied by the air pipe at the junction of the gas pipe and the air pipe. and an air flow rate control step of controlling the flow rate of the air flowing through the air pipe based on the air flow rate calculated by the flow rate calculator.

ADVANTAGE OF THE INVENTION According to this invention, the mixed gas whose component composition is unknown can be burned stably.

It is a figure which shows an example of the control system which concerns on embodiment of this invention. It is a figure which shows an example of a structure of the control apparatus which concerns on embodiment of this invention. FIG. 2 is a diagram showing an example of a simulated fuel supply system for fuel composed of three kinds of gases according to the embodiment of the present invention; It is a figure which shows an example of the flame height which concerns on embodiment of this invention. FIG. 4 is a diagram showing an example of a component ratio of simulated fuel gas according to the embodiment of the present invention; FIG. 4 is a diagram showing an example of a method of changing the flow rate of each gas contained in the simulated fuel gas according to the embodiment of the present invention; It is a figure which shows an example of fuel flow constant conditions which concern on embodiment of this invention. It is a figure which shows an example of equivalence-ratio constant conditions which concern on embodiment of this invention. It is a figure which shows an example of the calculation method of the delay time which concerns on embodiment of this invention. It is a figure which shows an example of the relationship between the volume fraction of methane and the output value of a gas density meter which concerns on embodiment of this invention. FIG. 4 is a diagram showing an example of the relationship between the correction value of the gas mass flow controller and the volume fraction of methane according to the embodiment of the present invention; FIG. 4 is a diagram showing an example of temporal changes of various variables under fuel composition switching conditions using the gas density meter according to the embodiment of the present invention. It is a figure which shows an example of the experimental result in each condition which concerns on embodiment of this invention. FIG. 5 is a diagram showing an example of experimental results under a constant equivalence ratio condition for comparison with the present embodiment. It is a figure which shows an example of the experimental result on the fuel flow rate constant condition for comparison with this embodiment. FIG. 5 is a diagram showing a first example of experimental results in air flow rate control for comparison with the present embodiment; FIG. 7 is a diagram showing a second example of experimental results in fuel flow rate control for comparison with the present embodiment;

(embodiment)
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of a control system S according to this embodiment. The control system S includes a natural gas supply system R1, a gas density meter 3, a gas mass flow controller (MFC) 4, a signal converter 5, a compressor 6, a valve V1, an air mass flow controller 7, and a controller 8. , an AD/DA conversion board 9, a burner 10, a gas pipe GP1, a gas pipe GP2, a gas pipe GP3, and an air pipe AP.

A natural gas supply system R1 supplies the control system S with natural gas G0. The natural gas supply system R1 includes a gas tank 1, a gas tank 2, a valve V11, a valve V12, and a gas pipe GP0. The natural gas supply system R1 is connected to the gas density meter 3 via a gas pipe GP1.

Gas tank 1 stores a first natural gas. A valve V11 is provided between the gas tank 1 and the gas pipe GP0. The valve V11 allows the first natural gas to flow from the gas tank 1 into the gas pipe GP0 at a constant pressure.
Gas tank 2 stores a second natural gas. Here, the composition ratio of the second natural gas is different from the composition ratio of the first natural gas. A valve V12 is provided between the gas tank 2 and the gas pipe GP0. The valve V12 allows the second natural gas to flow from the gas tank 2 into the gas line GP0 at a constant pressure.
Valve V11 and valve V12 are pressure reducing valves.

Natural gas G0 is supplied from gas tank 1 or gas tank 2 . The natural gas G0 is the first natural gas supplied from the gas tank 1, the second natural gas supplied from the gas tank 2, or the first natural gas supplied from the gas tank 1 and the gas tank 2. It is a mixed gas with the second natural gas that is used.
Gas pipe GP0 is connected via position P to gas pipe GP1.
Hereinafter, the natural gas G0 may be distinguished by different names such as a gas before density measurement G1, a gas after density measurement G2, and a gas after flow rate adjustment G3, depending on the gas pipe through which the natural gas G0 passes.

The gas density meter 3 measures the density of the pre-density-measurement gas G1 flowing from the gas pipe GP1. Here, the gas before density measurement G1 is the natural gas G0 supplied from the natural gas supply system R1.
The gas density meter 3 is, for example, a vibrating gas density meter. The gas density meter 3 incorporates a thin-walled cylindrical vibrator (resonator), and its resonance frequency changes depending on the density of the pre-density-measurement gas G1 flowing around it. The gas density meter 3 measures the density of the pre-density-measurement gas G1 by measuring this resonance frequency.

The gas density meter 3 is connected to the gas mass flow controller 4 via a gas pipe GP2. The density of the pre-density-measurement gas G1 is measured by the gas density meter 3 and flows into the gas mass flow controller 4 as the post-density-measurement gas G2. The time required for the density-measured gas G2 to reach the gas mass flow controller 4 from the gas density meter 3 through the gas pipe GP2 is called a transmission time _tt . In other words, the transmission time _tt is the time corresponding to the distance from the measurement position on the path of the gas pipe where the gas density meter 3 is arranged to the gas mass flow controller 4 .

On the other hand, the gas density meter 3 is connected to the signal converter 5 by wiring for input/output signals. The gas density meter 3 outputs a current indicating the measured density value to the signal converter 5 .

The gas mass flow controller 4 controls the flow rate of the density-measured gas G2 under the control of the controller 8 . The gas mass flow controller 4 is a valve that is arranged on the path of the gas pipe and adjusts the flow rate of the natural gas G0 flowing through the gas pipe. A gas mass flow controller 4 is arranged downstream of the gas density meter 3 .
Gas mass flow controller 4 is controlled by controller 8 via AD/DA conversion board 9 . The gas mass flow controller 4 is connected to the AD/DA conversion board 9 by wiring for input/output signals.

The gas mass flow controller 4 is connected to the confluence point β via a gas pipe GP3. The density-measured gas G2 is flow-controlled by the gas mass flow controller 4 and flows into the confluence point β as the flow-rate-adjusted gas G3. The time required for the flow-adjusted gas G3 to reach the confluence point β from the gas mass flow controller 4 through the gas pipe GP3 is called a delay time _td . Also, let L be the length of the gas pipe GP3. The length L is equal to the distance from the gas mass flow controller 4 to the junction β.

The signal converter 5 converts the current value output by the gas density meter 3 into a voltage value. The signal converter 5 supplies the converted voltage value to the AD/DA conversion board 9 . The signal converter 5 is connected to the AD/DA conversion board 9 by wiring for input/output signals.

Compressor 6 supplies air AR via valve V1 and air mass flow controller 7 to junction β. A valve V1 is provided between the compressor 6 and the air mass flow controller 7 . Valve V1 allows air AR to flow from compressor 6 to air mass flow controller 7 at constant pressure. Valve V1 is a pressure reducing valve.

The air mass flow controller 7 controls the flow rate of the air AR under the control of the controller 8 . The air mass flow controller 7 is a valve that is arranged on the route of the air pipe AP and adjusts the flow rate of the air AR that flows through the air pipe AP. The air mass flow controller 7 is connected to the junction β via an air pipe AP. The air AR whose flow rate is controlled by the air mass flow controller 7 flows into the confluence point β.
The air mass flow controller 7 is connected to the AD/DA conversion board 9 by wiring for input/output signals.

A control device 8 controls the gas mass flow controller 4 and the air mass flow controller 7 via an AD/DA conversion board 9 . In other words, the control device 8 controls the flow rate of the flow-adjusted gas G3 flowing out from the gas mass flow controller 4 and the flow rate of the air AR flowing out from the air mass flow controller 7 .
The control device 8 is connected to the AD/DA conversion board 9 by wiring for input/output signals. The control device 8 is, for example, a PC (Personal Computer).

The AD/DA conversion board 9 acquires the density value of the pre-density-measurement gas G<b>1 supplied from the gas density meter 3 via the signal converter 5 . The AD/DA conversion board 9 supplies the acquired density value of the pre-density-measurement gas G1 to the controller 8 .
The AD/DA conversion board 9 supplies a control signal for controlling the gas mass flow controller 4 to the gas mass flow controller 4 through wiring for input/output signals under the control of the control device 8 .
The AD/DA conversion board 9 supplies a control signal for controlling the air mass flow controller 7 to the air mass flow controller 7 via wiring for input/output signals under the control of the control device 8 .

The burner 10 burns the air-mixed gas G4 flowing from the junction β to form a flame. Here, the air mixed gas G4 is a gas obtained by mixing the flow-adjusted gas G3 that has passed through the gas pipe GP3 and the air AR that has passed through the air pipe AP.

Next, the configuration of the control device 8 will be described with reference to FIG.
FIG. 2 is a diagram showing an example of the configuration of the control device 8 according to this embodiment. The control device 8 includes a density acquisition section 80, a component ratio calculation section 81, a flow rate calculation section 82, a gas flow rate control section 83, a delay time calculation section 84, a storage section 85, and an air flow rate control section 86. Prepare.

The density acquisition unit 80 acquires the value of the density of the post-density-measurement gas G2 measured by the gas density meter 3 . Here, the density acquisition unit 80 acquires the density value of the post-density-measurement gas G2 via the signal converter 5 and the AD/DA conversion board 9 . However, the signal converter 5 and the AD/DA conversion board 9 are omitted in FIG.
The density obtaining unit 80 supplies the obtained density value of the post-density-measurement gas G<b>2 to the component ratio calculating unit 81 . Further, the density acquisition unit 80 supplies the acquired density value of the post-density-measurement gas G<b>2 to the delay time calculation unit 84 .

The component ratio calculator 81 calculates the component ratio of the post-density-measurement gas G<b>2 from the value of the density of the post-density-measurement gas G<b>2 acquired by the density acquisition unit 80 . The component ratio calculator 81 supplies the calculated component ratio of the density-measured gas G<b>2 to the flow rate calculator 82 .

Here, the density value of the post-density-measurement gas G2 acquired by the density acquisition unit 80 is the density value of the natural gas G0 at the measurement position on the route of the gas pipe in which the gas density meter 3 is arranged. Therefore, the component ratio calculator 81 calculates the component ratio of the mixed gas based on the density of the natural gas G0 at the measurement position on the route of the gas pipe where the gas density meter 3 for measuring the density indicating the component ratio of the natural gas G0 is arranged. Calculate the ratio.

The flow rate calculator 82 calculates the gas flow rate of the gas G3 after flow rate adjustment and the air flow rate of the air AR flowing out from the gas mass flow controller 4 based on the component ratio of the gas G2 after density measurement calculated by the component ratio calculator 81. do. Here, when the total flow rate of the gas G3 after the flow rate adjustment and the air AR is constant and the equivalence ratio between the gas G3 after the flow rate adjustment and the air AR is constant, the gas flow rate of the gas G3 after the flow rate adjustment is calculated as follows: and the air flow rate of the air AR.
The flow rate calculator 82 supplies gas flow rate information indicating the calculated gas flow rate to the gas flow rate controller 83 . In addition, the flow rate calculator 82 supplies air flow rate information indicating the calculated air flow rate to the air flow rate controller 86 .

Here, the fixed total flow rate of the gas G3 after flow rate adjustment and the air AR means that the flow rate of the gas G3 after flow rate adjustment flowing into the confluence point β and the flow rate of the air AR flowing into the confluence point β are each constant. This is the condition. In other words, the constant total flow rate of the gas G3 after flow rate adjustment and the air AR is a condition under which the flow rate of the air-mixed gas G4 flowing out from the confluence point β is constant.
Further, the constant equivalence ratio between the gas G3 and the air AR after the flow rate adjustment refers to the value obtained by dividing the volume ratio of the gas G3 and the air AR after the flow rate adjustment by the volume ratio of the fuel and air in the stoichiometric mixture ratio. 1).

Here, Q _fuel represents the volume of gas G3 after flow rate adjustment, and Q _air represents the volume of air AR. Also, the stoichiometric fuel-air ratio (F/A) _st represents the volume ratio of fuel and air in the stoichiometric mixture ratio.
The constant equivalence ratio between the gas G3 after flow rate adjustment and the air AR is a condition that the equivalence ratio of the air-mixed gas G4 flowing out from the confluence point β is constant.

As described above, the flow rate calculation unit 82 sets the total flow rate of the natural gas G0 whose composition is unknown and the air AR mixed with the natural gas G0 to be constant, and the equivalence ratio between the natural gas G0 and the air AR. When constant, the gas flow rate of the natural gas G0 and the air flow rate of the air AR are calculated based on the component ratio of the natural gas G0. Here, the component ratio of the natural gas G0 is the component ratio indicated by the density of the natural gas G0 calculated by the component ratio calculator 81 . Therefore, the flow rate calculator 82 calculates the gas flow rate of the natural gas G0 and the air flow rate of the air AR based on the component ratio of the natural gas G0 indicated by the density of the natural gas G0 calculated by the component ratio calculator 81 .

The gas flow rate control section 83 controls the gas mass flow controller 4 based on the gas flow rate information supplied by the gas flow rate control section 83 . The gas flow rate control unit 83 controls the flow rate of the gas G3 after flow rate adjustment by controlling the gas mass flow controller 4 . Here, the gas flow rate control unit 83 supplies a signal for controlling the flow rate of the gas G3 after flow rate adjustment to the gas mass flow controller 4 via the AD/DA conversion board 9 .
As described above, the gas flow control section 83 controls the flow rate of the natural gas G0 flowing through the gas pipe GP3 based on the gas flow rate calculated by the flow rate calculation section 82 .

The delay time calculator 84 calculates the delay time TDT according to the distance from the measurement position on the route of the gas pipe where the gas density meter 3 is arranged to the confluence point β. In the delay time TDT, the gas G2 after the density measurement flows from the gas density meter 3 through the gas pipe GP2 into the gas mass flow controller 4, flows out from the gas mass flow controller 4 as the gas G3 after the flow rate adjustment, and passes through the gas pipe GP3. is the time required to reach the confluence point β. Therefore, the delay time TDT is equal to the transmission time _tt plus the delay time _td .
The delay time calculator 84 may calculate the transmission time _tt and the delay time _td , respectively, and add the calculated transmission time _tt and the delay time _td to obtain the delay time TDT.

Here, an example will be described in which the delay time calculator 84 calculates a correction value for correcting the pre-calculated initial delay time TDT0 when calculating the delay time TDT.
The delay time calculator 84 acquires the value of the density of the post-density-measurement gas G<b>2 supplied from the density acquirer 80 . The delay time calculator 84 acquires the delay time information 850 from the storage unit 85 . Here, the delay time information 850 is information indicating the initial delay time TDT0. The initial delay time _td0 is the value of the delay time TDT calculated in advance according to the length of the gas pipe GP2 and the length (length L) of the gas pipe GP3.

The delay time calculation unit 84 calculates the delay time TDT by correcting the initial delay time TDT0 indicated by the delay time information 850 based on the obtained density value of the density-measured gas G2. That is, the delay time calculator 84 calculates a correction value for correcting the pre-calculated initial delay time TDT0.

Here, the initial delay time TDT0 is a time calculated based on the distance from the measurement position on the path of the gas pipe where the gas density meter 3 is arranged to the confluence point β. Therefore, the delay time calculation unit 84 calculates the delay time TDT based on the density of the natural gas G0 and the distance from the measurement position on the route of the gas pipe where the gas density meter 3 is arranged to the confluence point β. do.
The delay time calculator 84 supplies the calculated delay time TDT to the air flow controller 86 .
Storage unit 85 stores delay time information 850 .

The air flow control unit 86 controls the flow rate of the air AR flowing through the air pipe AP based on the delay time TDT calculated by the delay time calculation unit 84 and the air flow rate of the air AR calculated by the flow rate calculation unit 82 .

Here, the delay time TDT calculated by the delay time calculation unit 84 is defined as the distance from the measurement position on the path of the gas pipe where the gas density meter 3 for measuring the density indicating the component ratio of the gas G2 after density measurement is arranged. This is the time corresponding to the distance to the confluence point β where the flow rate-adjusted gas G3 supplied by GP3 and the air AR supplied by the air pipe AP are mixed at the joint between the gas pipe GP3 and the air pipe AP.
Therefore, the air flow controller 86 controls the flow rate of the natural gas G0 and the air supplied by the gas pipe from the measurement position on the gas pipe route where the gas density meter 3 for measuring the physical quantity indicating the component ratio of the natural gas G0 is arranged. Based on the delay time TDT corresponding to the distance to the confluence point β where the air AR supplied by the pipe is mixed at the connection portion between the gas pipe and the air pipe AP, and the air flow rate calculated by the flow rate calculation unit 82, It controls the flow rate of the air AR flowing through the air pipe AP. Here, the physical quantity indicating the component ratio of the natural gas G0 is the density of the mixed gas.

Also, the air flow rate control section 86 may control the air flow rate of the air AR based on the transmission time _tt calculated by the delay time calculation section 84 . Here, the air flow rate control unit 86 may control the air flow rate of the air AR based on the transmission time _tt in addition to the delay time _td , or may control the air flow rate of the air AR based only on the transmission time _tt . may be controlled.

In the present embodiment, the case where the delay time calculator 84 calculates a correction value for correcting the pre-calculated initial delay time _td0 has been described as an example, but the present invention is not limited to this. The delay time calculator 84 may calculate the delay time TDT based on the value of the density of the post-density-measurement gas G2. When the delay time calculation unit 84 calculates the delay time TDT based on the value of the density of the post-density-measurement gas G2, the delay time information 850 does not have to be stored in the storage unit 85 .

Further, in the present embodiment, a case where the density value of the mixed gas acquired by the density acquisition unit 80 is measured by the gas density meter 3 will be described, but the present invention is not limited to this. The value of the density of the mixed gas acquired by the density acquisition unit 80 may be measured, for example, by an optical method using a laser, gas chromatography, or the like.

In the following, in order to explain the effect of the control system S, the case where the control system S includes a simulated fuel supply system R2 instead of the natural gas supply system R1 and controls the flow rate of a mixed gas with a known component ratio is described. explain.

FIG. 3 is a diagram showing an example of a simulated fuel supply system R2 for fuel composed of three kinds of gases according to this embodiment. A simulated fuel supply system R2 is connected to the control system S shown in FIG. Here, the simulated fuel gas G10 is a mixed gas for simulating natural gas and contains methane, ethane, and propane. The combustion characteristics of natural gas are known to be nearly similar to those of three gas mixtures of methane, ethane and propane. The component ratio of the simulated fuel gas G10 is known. The component ratio of the simulated fuel gas G10 will be described later with reference to FIG.

The simulated fuel supply system R2 includes a methane cylinder C1, an ethane cylinder C2, a propane cylinder C3, a valve V21, a valve V22, a valve V23, a gas mass flow controller 21, a gas mass flow controller 22, a gas mass flow controller 23, and a valve V3 and a gas pipe GP10.

Methane cylinder C1 stores methane. A valve V<b>21 is provided between the methane cylinder C<b>1 and the gas mass flow controller 21 . Valve V21 allows methane to flow from methane cylinder C1 to gas mass flow controller 21 at constant pressure.
Ethane cylinder C2 stores ethane. A valve V<b>22 is provided between the ethane cylinder C<b>2 and the gas mass flow controller 22 . Valve V22 allows ethane to flow from ethane cylinder C2 to gas mass flow controller 22 at constant pressure.
Propane cylinder C3 stores propane. A valve V23 is provided between the propane cylinder C3 and the gas mass flow controller 23. Valve V23 allows propane to flow from propane cylinder C3 to gas mass flow controller 23 at constant pressure.

A gas mass flow controller 21 controls the flow rate of methane. A gas mass flow controller 22 controls the flow rate of ethane. A gas mass flow controller 23 controls the flow rate of propane. Gas mass flow controller 21 , gas mass flow controller 22 , and gas mass flow controller 23 are controlled by controller 8 via AD/DA conversion board 9 .

Methane supplied from the gas mass flow controller 21, ethane supplied from the gas mass flow controller 22, and propane supplied from the gas mass flow controller 23 are joined and mixed at the confluence point α. Each mixed gas flows into the position P through the gas pipe GP10 as the simulated fuel gas G10.

A valve V3 is installed in a flow path leading to the outside air. The valve V3 controls the flow rate of the simulated fuel gas G10 independently of the flow rates of methane supplied from the gas mass flow controller 21, ethane supplied from the gas mass flow controller 22, and propane supplied from the gas mass flow controller 23. It's a valve.

In this embodiment, the flame height H is measured to check the stability of the flame formed in the burner 10. FIG. The flame height H will now be described with reference to FIG.
FIG. 4 is a diagram showing an example of the flame height H according to this embodiment. Flame height H is the height from the exit of burner 10 to the tip of the flame. The flame height H is measured, for example, by photographing the behavior of the flame using a high-speed camera equipped with an image intensifier.

Next, the component ratio of the simulated fuel gas G10 will be explained.
FIG. 5 is a diagram showing an example of the component ratio of the simulated fuel gas G10 according to this embodiment. In this embodiment, simulated fuel gas G10 having five different component ratios of methane, ethane, and propane is used. However, the case where the component ratio of the simulated fuel gas G10 changes from component ratio type A to component ratio type E will be described below as an example.

A method of changing the flow rate of each gas contained in the simulated fuel gas G10 will be described.
FIG. 6 is a diagram showing an example of a method for changing the flow rate of each gas contained in the simulated fuel gas G10 according to this embodiment. In this embodiment, the gas mass flow controller 21, the gas mass flow controller 22, the gas mass flow controller 23, and the air mass flow controller 7 are used to control the flow rates of methane, ethane, propane, and air AR, and the components of the simulated fuel gas G10 Realize a transitional change in the ratio.

When switching the simulated fuel gas G10 from one component ratio to another, the flow rate of each gas contained in the simulated fuel gas G10 was changed linearly. Here, the time required for switching is defined as transition time _tv .
The control device 8 supplies a signal for controlling the flow rate to the gas mass flow controller 21, the gas mass flow controller 22, the gas mass flow controller 23, and the air mass flow controller 7 every 20 ms, and switches the flow rate of each gas.

Next, with reference to FIGS. 7 and 8, the conditions for the flow rates of the simulated fuel gas G10 and air during transient changes in the component ratio of the simulated fuel gas G10 will be described.
FIG. 7 is a diagram showing an example of a constant fuel flow rate condition according to this embodiment. Here, the total flow rate is the sum of the flow rate of the simulated fuel gas G10 and the flow rate of the air AR. Under the constant fuel flow rate condition, the flow rate of the simulated fuel gas G10 and the flow rate of the air AR are kept constant, and the component ratio of the simulated fuel gas G10 is switched. The total flow rate in this embodiment is, for example, a flow rate at which the average flow velocity of the air-mixed gas G4 at the outlet of the burner 10 is 0.8 m/s.

FIG. 8 is a diagram showing an example of equivalence ratio constant conditions according to the present embodiment. Under the constant equivalence ratio condition, the component ratio of the simulated fuel gas G10 is switched so that the equivalence ratio becomes a constant value. Under the constant equivalence ratio condition of the present embodiment, the equivalence ratio is, for example, a constant value of 0.85.

In the control system S of this embodiment, the air flow rate is calculated based on the delay time TDT. Unlike the control system S, when the air flow rate is calculated without being based on the delay time TDT, the flame height H fluctuates with time and overshoots.
Here the change in flow rate is transmitted by pressure propagation. Therefore, changes in flow rate propagate at the speed of sound. On the other hand, changes in component ratios propagate at convective velocities. A change in component ratio propagates slower than a change in flow rate propagates. In the control system S, in controlling the fuel flow rate, the time required to transmit changes in the flow rate is negligibly short, but the time required to transmit changes in the component ratio is long to the extent that it cannot be ignored. It is considered that the reason why the flame height H overshoots is that the delay time TDT occurs according to the length from the position where the component ratio changes to the confluence point β.

Experimental results when the air flow rate is calculated without being based on the delay time TDT will be described with reference to FIGS. 14 and 15 for comparison with the present embodiment. 14 and 15 show graphs respectively showing the fuel flow rate at the confluence point α, the fuel flow rate at the confluence point β, the air flow rate, and the equivalence ratio at the confluence point β. Here, the fuel flow rate is the flow rate of the simulated fuel gas G10.

FIG. 14 is a diagram showing an example of experimental results under a constant equivalence ratio condition for comparison with the present embodiment. In the example of FIG. 14, the component ratio of the simulated fuel gas G10 changes from component ratio type A to component ratio type E under the constant equivalence ratio condition.

First, at the junction α, the change in the component ratio of the simulated fuel gas G10 and the change in the fuel flow rate occur only during the transition time _tv (time t11 to time t12). When the component ratio of the simulated fuel gas G10 changes and the fuel flow rate changes at the confluence point α, the air flow rate changes at the same time (time t11 to time t12).
However, at the confluence point β, the fuel flow rate changes instantaneously (time t11 to time t12). It takes only the delay time t _d (time t11 to time t13) corresponding to the time.
Therefore, the simulated fuel gas G10 of the component ratio type A flows at a flow rate smaller than that assumed in accordance with the simulated fuel gas G10 of the component ratio type E, and the equivalence ratio becomes smaller than assumed under the constant equivalence ratio condition. Since the equivalence ratio is smaller than assumed under the constant equivalence ratio condition, it is considered that the flame height H overshoots.

FIG. 15 is a diagram showing an example of experimental results under constant fuel flow rate conditions for comparison with the present embodiment. In the example of FIG. 15, under the constant fuel flow rate condition, the component ratio of the simulated fuel gas G10 changes from component ratio type A to component ratio type E (time t21 to time t22). Note that the air flow rate is constant under the constant fuel flow rate condition.
First, at the junction α, the change in the component ratio of the simulated fuel gas G10 occurs only during the transition time _tv . Here, the component ratio of the simulated fuel gas G10 changes from the component ratio type A to the component ratio type E by linearly decreasing the component ratio type A and linearly increasing the component ratio type E. When the change in the component ratio of the simulated fuel gas G10 occurs at the confluence point α for the transition time tv, at the confluence point β, the change in the component ratio of the simulated fuel gas _G10 occurs for the transition time _tv after the delay time _td (time t23 to time t24).

Under the constant fuel flow rate condition, there is no change in the air flow rate and no change in the fuel flow rate, so the equivalence ratio does not change due to the delay time _td , and the time at which the change in the component ratio reaches the outlet of the burner 10 changes. Under the constant fuel flow rate condition, the magnitude of change in the flame height H does not depend on the length of the passage of the simulated fuel gas G10, and the start time of the change differs according to the length of the passage.

Next, with reference to _FIGS . 16 and 17, experimental results in the case where the equivalence ratio of the simulated fuel gas G10 at the confluence point β is kept constant in consideration of the delay time td will be described.
FIG. 16 is a diagram showing a first example of experimental results in air flow rate control for comparison with the present embodiment. In the example of FIG. 16, under the constant equivalence ratio condition, the component ratio of the simulated fuel gas G10 changes from component ratio type A to component ratio type E (time t31 to time t32). However, in the example of FIG. 16, the fuel flow rate of the simulated fuel gas G10 becomes a smaller value than assumed under the constant equivalence ratio condition when the component ratio of the simulated fuel gas G10 changes.

Since the fuel flow is less than expected in the constant equivalence ratio condition, the air flow is controlled to temporarily decrease during the delay time _td . Therefore, although the equivalence ratio is kept constant, the total flow rate temporarily decreases (time t31 to time t34). In the example of FIG. 16, the total flow rate is controlled so that the average flow velocity of the air-mixed gas G4 at the outlet of the burner 10 is 0.8 m/s before and after the change in the component ratio of the simulated fuel gas G10. there is

FIG. 17 is a diagram showing a second example of experimental results in fuel flow rate control for comparison with the present embodiment. In the example of FIG. 17, under the constant equivalence ratio condition, the component ratio of the simulated fuel gas G10 changes from component ratio type A to component ratio type E (time t41 to time t42).
The fuel flow rate is maintained at a value corresponding to the component ratio type A from when the change in the component ratio of the simulated fuel gas G10 at the junction α occurs until the delay time _td elapses. As a result, the fuel flow rate does not change until the change in the component ratio reaches the confluence point β (time t41 to time t43). The air flow rate also does not change until the change in the component ratio reaches the confluence point β (time t41 to time t43). Therefore, in the example of FIG. 17, the equivalence ratio and total flow rate are kept constant. Here, the total flow rate is controlled so that the average flow velocity of the air mixed gas G4 at the outlet of the burner 10 is 0.8 m/s.

In the control based on the delay time td in _FIGS . 16 and 17, it is necessary to calculate the delay time _td according to the length L of the flow path from the junction α to the junction β. Here, a method for calculating the delay time _td will be described with reference to FIG.
FIG. 9 is a diagram showing an example of a delay time calculation method according to the present embodiment. The delay time _td depends on the fuel flow rate. Here, since the fuel flow rate changes with time, the delay time _td also changes with time. Assuming that the volume of the simulated fuel gas G10 corresponding to the delay time td is the volume Vd( _t ), the volume Vd(t) is expressed using Equation (2).

Here, the area A _channel is the cross-sectional area of the channel from the junction α to the junction β. On the other hand, volume Vd(t) can be expressed using equation (3).

where the flow rate Q _fuel (t) is the fuel flow rate. Therefore, the lag time _td is calculated by solving the equation for the lag time td obtained by eliminating the volume Vd( _t ) from equations (2) and (3). However, the integration of equation (3) is calculated by treating the time and the flow rate Q _fuel (t) as discrete values as shown in FIG.

Next, with reference to FIGS. 10 and 11, a method of measuring the density of the simulated fuel gas G10 with the gas density meter 3, detecting changes in the component ratio of the simulated fuel gas G10 with the control device 8, and controlling the flow rate. explain.
FIG. 10 is a diagram showing an example of the relationship between the volume fraction of methane and the output value of the gas density meter 3 according to this embodiment. A graph GR1 shows the relationship between the volume fraction of methane and the output value of the gas density meter 3 for a given component ratio of the simulated fuel gas G10 in the steady state.

In the predetermined component ratio of the simulated fuel gas G10 in the steady state, the volume fraction of methane, the volume fraction of ethane, and the volume fraction of propane are paired for each volume fraction of methane. However, in the predetermined component ratio of the simulated fuel gas G10 in the steady state, the ratio of the volume fraction of ethane to the volume fraction of propane was set to 5:1 regardless of the volume fraction of methane.

From the graph GR1, the volume fraction of methane and the output value of the gas density meter 3 are linear. Therefore, the volume fraction of methane can be calculated from the output value of the gas density meter 3 from the graph GR1. Furthermore, the component ratio of the simulated fuel gas G10 can be calculated from the volume fraction of methane using a predetermined component ratio of the simulated fuel gas G10 in the steady state.

Next, the relationship between the component ratio of the simulated fuel gas G10 and the gas flow rate output by the gas mass flow controller 4 will be described with reference to FIG.

FIG. 11 is a diagram showing an example of the relationship between the correction value of the gas mass flow controller 4 and the volume fraction of methane according to this embodiment. The gas flow rate output by the gas mass flow controller 4 depends on the type of flowing gas. Therefore, if the component ratio of the simulated fuel gas G10 changes, the output flow rate will change even if the gas mass flow controller 4 is given the same flow rate indication value. Therefore, it is necessary to calibrate the indicated flow rate and the actual flow rate.
A coefficient kMFC for correcting the actual flow rate Q output with respect to the flow rate command value Qinput is defined using equation (4).

A graph GR2 shows the relationship between the coefficient kMFC, which is the correction coefficient of the gas mass flow controller 4, and the volume fraction of methane. Graph GR2 is approximated by a quadratic function.

Next, a method for calculating the fuel flow rate from the volume fraction of methane will be described. The equivalence ratio r is represented by Equation (1) described above. Assuming that the volume fraction of methane is Φ _CH4 , the volume fraction of ethane is Φ _C2H6 , and the volume fraction of propane is Φ _C3H8 , the stoichiometric fuel-air ratio (F/A) _st in equation (1) is expressed by equation (5) is represented using

Therefore, the stoichiometric fuel-air ratio (F/A) _st is expressed as a function of the volume fraction of methane. However, the value of the international standard atmosphere was used for the volume fraction of oxygen in the air. Also, the total flow rate Q _total is expressed as in Equation (6).

Under the constant equivalence ratio condition and the constant fuel flow rate condition, if the volume fraction of methane is known from equations (1), (5), and (6), the flow rate Q _fuel and the air flow rate Q _air can be calculated by the formula It can be calculated using (7) and equation (8).

In the flow path system in which the gas density meter 3 is installed, it takes a transmission time _tt for the simulated fuel gas G10 having the component ratio output from the gas density meter 3 to reach the gas mass flow controller 4 . Also, it takes a delay time _td for the simulated fuel gas G10 to reach the confluence point β from the outlet of the gas mass flow controller 4 . Therefore, the command value Q _input to the gas mass flow controller 4 at time t is expressed by equation (9) from equations (4) and (7).

Here, Φ _input is the volume fraction of methane obtained from the value of the density of the simulated fuel gas G10 measured by the gas density meter 3.

FIG. 12 is a diagram showing an example of temporal changes of various variables under fuel composition switching conditions using the gas density meter 3 according to the present embodiment. In FIG. 12, the component ratio of the simulated fuel gas G10 changes from component ratio type A to component ratio type E. In FIG.

First, the flow rate of each gas at the junction α changes during the transition time _tv (time t1 to time t2), and the component ratio of the simulated fuel gas G10 at the junction α changes.
Next, the density of the simulated fuel gas G10 at the position where the gas density meter 3 is arranged changes (time t3 to time t4).

The coefficient k _MFC of the gas mass flow controller 4 is calibrated according to changes in the component ratio of the simulated fuel gas G10 (time t5 to time t6). The fuel flow rate at the position where the gas mass flow controller 4 is arranged is controlled with a delay of the transmission time _tt and the delay time _td . Here, the transmission time _tt is the time required for the simulated fuel gas G10 to propagate from the gas density meter 3 to the gas mass flow controller 4 through the gas pipe GP2. The delay time _td is the time required for the simulated fuel gas G10 to propagate through the gas pipe GP3 from the gas mass flow controller 4 to the confluence point β.
The transmission time _tt is calculated using the equations (2) and (3) in the same manner as the delay time _td .

The gas mass flow controller 4 controls the fuel flow rate of the simulated fuel gas G10 with a delay of the transmission time t _t and the delay time t _d (time t7 to time t8). Since the change in flow rate is transmitted by pressure propagation, the fuel flow rate at the confluence point β changes almost simultaneously with the change in fuel flow rate at the gas mass flow controller 4 (time t7 to time t8).

FIG. 13 is a diagram showing an example of experimental results under each condition according to this embodiment. FIG. 13 shows time variations of the flame height H under five types of conditions: constant fuel flow rate, constant equivalence ratio, air flow rate control, fuel flow rate control, and density meter control. Here, FIG. 13 shows the time variation of the flame height H when the transition time _tv is 1 s and the distance from the confluence point α to the confluence point β is 1500 mm. In FIG. 13, the component ratio of the simulated fuel gas G10 changes from component ratio type A to component ratio type E. In FIG.

Under the constant fuel flow rate condition and the constant equivalence ratio condition, control considering the delay time _td is not performed. In air flow rate control and fuel flow rate control, control is performed in consideration of the delay time _td . In the density meter control, the fuel flow rate and the air flow rate are controlled by the controller 8 based on the density of the simulated fuel gas G10 measured by the gas density meter 3 .

Fuel flow rate control is the most effective in suppressing fluctuations in flame height H under the five conditions shown in FIG. 13 . In fuel flow rate control, fluctuations in the flame height H are caused only by changes in the calorific value flow rate due to switching of the component ratio of the simulated fuel gas G10. For fuel flow control, the difference between the maximum and minimum flame height H is about 0.7 mm.
On the other hand, in the air flow rate control, fluctuations in the flame height H were observed due to increases and decreases in the air flow rate and delays in the response of the gas mass flow controller 4 . With air flow control, the difference between the maximum and minimum flame height H is about 2.6 mm.

In the density meter control, fluctuations in the flame height H are caused by changes in the density distribution of the simulated fuel gas G10 due to Taylor diffusion and delay in the response of the gas density meter 3. FIG. With densitometer control, the difference between the maximum and minimum flame height H is about 1.4 mm. In the density meter control, fluctuations in the flame height H can be suppressed as compared with the constant fuel flow rate condition and the constant equivalence ratio condition. Also, the variation in the flame height H under density meter control is not significantly larger than the variation in flame height H under fuel flow rate control.
Therefore, in the density meter control performed by the control device 8 based on the density of the simulated fuel gas G10 measured by the gas density meter 3, fluctuations in the flame height H could be suppressed.

As described above, the control device 8 according to this embodiment includes the flow rate calculator 82 , the gas flow rate controller 83 , and the air flow rate controller 86 .
The flow rate calculation unit 82 sets the total flow rate of the mixed gas (natural gas G0, simulated fuel gas G10) whose composition is unknown and the air AR mixed with the mixed gas (natural gas G0, simulated fuel gas G10) to be constant, In addition, when the equivalence ratio of the mixed gas (natural gas G0, simulated fuel gas G10) and air AR is constant, based on the component ratio of the mixed gas (natural gas G0, simulated fuel gas G10), the mixed gas (natural The gas flow rate of gas G0 and simulated fuel gas G10) and the air flow rate of air are calculated.
The gas flow rate control unit 83 controls the flow rate of the mixed gas (natural gas G0, simulated fuel gas G10) flowing through the gas pipe based on the gas flow rate calculated by the flow rate calculation unit 82 .
The air flow control unit 86 controls the flow rate of the mixed gas supplied by the gas pipe from a measurement position on the route of the gas pipe where the measuring unit (gas density meter 3) for measuring the physical quantity (density) indicating the component ratio of the mixed gas is arranged. Depending on the distance to the gas-air mixing section (confluence point β) where the gas (natural gas G0, simulated fuel gas G10) and the air AR supplied by the air pipe AP are mixed at the connection between the gas pipe and the air pipe AP The flow rate of the air AR flowing through the air pipe AP is controlled based on the delay time TDT obtained and the air flow rate calculated by the flow rate calculator 82 .

With this configuration, the control device 8 according to the present embodiment can control the air flow rate of the air AR based on the delay time TDT, so that the mixed gas whose component composition is unknown can be stably burned.

Further, the control device 8 according to this embodiment further includes a component ratio calculator 81 . In the control device 8 according to this embodiment, the physical quantity indicating the component ratio of the mixed gas is the density of the mixed gas (natural gas G0, simulated fuel gas G10).
The component ratio calculation unit 81 calculates the density indicating the component ratio of the mixed gas at the measurement position on the route of the gas pipe where the measurement unit (gas density meter 3) for measuring the physical quantity (density) indicating the component ratio of the mixed gas is arranged. , the component ratio of the mixed gas (natural gas G0, simulated fuel gas G10) is calculated.
Based on the component ratio of the mixed gas (natural gas G0, simulated fuel gas G10) indicated by the density calculated by the component ratio calculator 81, the flow rate calculation unit 82 calculates the gas mixture (natural gas G0, simulated fuel gas G10). A flow rate and an air flow rate of the air AR are calculated.

With this configuration, in the control device 8 according to the present embodiment, the component ratio of the mixed gas can be calculated in a shorter time than when using chromatography or the like. It is possible to stably burn the mixed gas in comparison.

In addition, in the control device 8 according to the present embodiment, the gas flow rate adjustment valve (gas mass flow controller 4) controlled by the gas flow rate control unit 83 is arranged in the gas pipe where the measuring unit (gas density meter 3) is arranged. Located downstream of the measurement position on the path. The air flow rate control unit 86 controls the air flow rate of the air AR based on the transmission time _tt corresponding to the distance from the measurement position to the gas flow control valve (gas mass flow controller 4).

With this configuration, the control device 8 according to the present embodiment can burn the unburned adjusted gas more stably than when not based on the transmission time.

Moreover, the control device 8 according to the present embodiment further includes a delay time calculator 84 . The delay time calculation unit 84 calculates the delay time TDT from the density of the mixed gas (natural gas G0, simulated fuel gas G10) and the measurement position on the route of the gas pipe where the measurement unit (gas density meter 3) is arranged. A gas-air mixing section (junction point β).

With this configuration, the control device 8 according to the present embodiment can burn the unburned adjusted gas more stably than when based on a predetermined delay time.

The control system S according to this embodiment also includes a control device 8, a gas flow rate adjustment valve (gas mass flow controller 4), and an air flow rate adjustment valve (air mass flow controller 7).
A gas flow control valve (gas mass flow controller 4) is arranged on the path of the gas pipe and adjusts the flow rate of the mixed gas (natural gas G0, simulated fuel gas G10) flowing through the gas pipe.
An air flow rate adjustment valve (air mass flow controller 7) is arranged on the path of the air pipe AP and adjusts the flow rate of the air AR flowing through the air pipe AP.
With this configuration, the control system S according to the present embodiment can control the air flow rate of the air AR based on the delay time TDT, so that the mixed gas whose component composition is unknown can be stably burned.

Note that a part of the control device 8 in the above-described embodiment, for example, the density acquisition unit 80, the component ratio calculation unit 81, the flow rate calculation unit 82, the gas flow control unit 83, the delay time calculation unit 84, and the air flow control unit 86 may be realized by a computer. In that case, a program for realizing this control function may be recorded in a computer-readable recording medium, and the program recorded in this recording medium may be read into a computer system and executed. The "computer system" here is a computer system built in the control device 8, and includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible discs, magneto-optical discs, ROMs and CD-ROMs, and storage devices such as hard discs incorporated in computer systems. Furthermore, "computer-readable recording medium" means a medium that dynamically stores a program for a short period of time, such as a communication line for transmitting a program via a network such as the Internet or a communication line such as a telephone line. It may also include a volatile memory inside a computer system that serves as a server or client in that case, which holds the program for a certain period of time. Further, the program may be for realizing part of the functions described above, or may be capable of realizing the functions described above in combination with a program already recorded in the computer system.
Also, part or all of the control device 8 in the above-described embodiment may be implemented as an integrated circuit such as an LSI (Large Scale Integration). Each functional block of the control device 8 may be individually processorized, or a part or all of them may be integrated and processorized. Also, the method of circuit integration is not limited to LSI, but may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integration circuit technology that replaces LSI appears due to advances in semiconductor technology, an integrated circuit based on this technology may be used.

Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes, etc., can be made without departing from the gist of the present invention. It is possible to

S... Control system, 1... Gas tank, 2... Gas tank, 3... Gas density meter, 4... Gas mass flow controller, 5... Signal converter, 6... Compressor, 7... Air mass flow controller, 8... Control device, 9... AD/ DA conversion board 10 Burner R1 Natural gas supply system R2 Simulated fuel supply system GP0, GP1, GP2, GP3, GP10 Gas pipe AP Air pipe C1 Methane cylinder C2 Ethane cylinder C3... propane cylinder, V1, V11, V12, V21, V22, V23, V3... valve, 21, 22, 23... gas mass flow controller, 80... density acquisition unit, 81... component ratio calculation unit, 82... flow rate calculation unit, 83... Gas flow control unit, 84... Delay time calculation unit, 85... Storage unit, 850... Delay time information, 86... Air flow control unit

Claims (6)

When the total flow rate of a mixed gas whose component composition is unknown and the air mixed with the mixed gas is constant, and the equivalence ratio between the mixed gas and the air is constant, based on the component ratio of the mixed gas a flow rate calculation unit that calculates the gas flow rate of the mixed gas and the air flow rate of the air;
a gas flow control unit that controls the flow rate of the mixed gas flowing through the gas pipe based on the gas flow rate calculated by the flow rate calculation unit;
The mixed gas supplied by the gas pipe and the air pipe supplied from a measurement position on the route of the gas pipe where a measuring unit for measuring the density of the mixed gas indicating the component ratio of the mixed gas is arranged The air pipe is calculated based on the delay time corresponding to the distance to the gas-air mixing portion where the air is mixed at the connection portion between the gas pipe and the air pipe, and the air flow rate calculated by the flow rate calculation unit. and an air flow rate control unit that controls the flow rate of the air flowing through the air flow control device. further comprising a component ratio calculator that calculates a component ratio of the mixed gas based on the density at the measurement position;
2. The flow rate calculation unit calculates the gas flow rate of the mixed gas and the air flow rate of the air based on the component ratio of the mixed gas indicated by the density calculated by the component ratio calculation unit. controller. A gas flow control valve controlled by the gas flow control unit is arranged downstream of the measurement position in the gas pipe,
The air flow rate control unit controls the air flow rate of the air based on the transmission time corresponding to the distance from the measurement position to the gas flow rate adjustment valve , the delay time, and the air flow rate calculated by the flow rate calculation unit. The control device according to claim 1 or 2, which controls the . The delay time calculator according to any one of claims 1 to 3, further comprising a delay time calculator that calculates the delay time based on the density of the mixed gas and the distance from the measurement position to the gas-air mixing unit. controller. A control device according to any one of claims 1 to 4;
a gas flow rate adjustment valve arranged on the path of the gas pipe for adjusting the flow rate of the mixed gas flowing through the gas pipe;
A control system comprising: an air flow adjustment valve arranged on a path of the air pipe and adjusting a flow rate of the air flowing through the air pipe. to the computer,
When the total flow rate of a mixed gas whose component composition is unknown and the air mixed with the mixed gas is constant, and the equivalence ratio between the mixed gas and the air is constant, based on the component ratio of the mixed gas a flow rate calculation step of calculating the gas flow rate of the mixed gas and the air flow rate of the air;
a gas flow rate control step of controlling the flow rate of the mixed gas flowing through the gas pipe based on the gas flow rate calculated in the flow rate calculation step;
The mixed gas supplied by the gas pipe and the air pipe supplied from a measurement position on the route of the gas pipe where a measuring unit for measuring the density of the mixed gas indicating the component ratio of the mixed gas is arranged Based on the delay time according to the distance to the gas-air mixing portion where the air is mixed at the connection portion between the gas pipe and the air pipe, and the air flow rate calculated in the flow rate calculation step, the air and an air flow rate control step of controlling the flow rate of the air flowing through the pipe.

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