JP6648603B2 - Fuel supply device - Google Patents

Description

  The present invention relates to a fuel supply device.

  For example, Patent Literature 1 below discloses a fuel supply control device that supplies gaseous fuel to a combustion chamber of an internal combustion engine. This fuel supply control device supplies CNG (Compressed Natural Gas), that is, pressurized natural gas to the combustion chamber as gaseous fuel.

JP 2015-101956 A

  Incidentally, the natural gas has a boiling point of about -160 ° C. at normal pressure, as is well known, and does not easily reliquefy even when pressurized to supply it to the combustion chamber. However, in the case of a gaseous fuel containing a substance having a boiling point close to normal temperature as a component, reliquefaction may be a concern, and stable supply to the combustion chamber may not be possible.

  The present invention has been made in view of the above circumstances, and has as its object to prevent re-liquefaction of a gaseous fuel during supply of the gaseous fuel.

  In order to achieve the above object, the present invention provides, as a first solution means relating to a fuel supply device, a fuel supply device for supplying gaseous fuel to a predetermined location via a flow control valve, which is externally input. According to the required flow rate, after adjusting the upstream pressure and / or the upstream temperature of the flow control valve so that the gaseous fuel does not liquefy on the downstream side of the flow control valve, the opening degree of the flow control valve is adjusted. A means of providing a supply control means for setting is adopted.

  In the present invention, as a second solving means according to the fuel supply device, in the first solving means, the supply control means includes a first pressure gauge for detecting an upstream pressure of the flow control valve; A first thermometer that detects an upstream temperature of the control valve, a second pressure gauge that detects a downstream pressure of the flow control valve, the upstream pressure, the upstream temperature, the downstream pressure, Means for setting a change value of the upstream pressure based on the flow coefficient of the flow control valve and the saturated vapor pressure curve of the gaseous fuel.

  In the present invention, as a third solution of the fuel supply device, in the first or second solution, the supply control means may control the gaseous fuel within a predetermined allowable range set at the upstream pressure. Set the change value of the upstream pressure so that it does not liquefy on the downstream side of the flow control valve, and if the change value cannot prevent liquefaction of the gaseous fuel, adjust the upstream temperature. Means is adopted.

  In the present invention, as a fourth solution according to the fuel supply device, in any one of the first to third solutions, the gaseous fuel is ammonia and the predetermined portion is a combustion chamber of a gas turbine. , Is adopted.

  According to the present invention, the upstream pressure and / or the upstream temperature of the flow control valve is adjusted so that the gaseous fuel does not liquefy on the downstream side of the flow control valve in accordance with the required flow rate input from the outside. Since the supply control means for setting the opening degree of the flow control valve is provided, it is possible to prevent the gaseous fuel from being re-liquefied in the supply of the gaseous fuel.

1 is a system configuration diagram illustrating a functional configuration of a fuel supply device according to an embodiment of the present invention. 4 is a flowchart illustrating an operation of the fuel supply device according to the embodiment of the present invention. FIG. 4 is a characteristic diagram illustrating an operation of the fuel supply device according to the embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The fuel supply device A according to the present embodiment is an ammonia supply device that supplies ammonia N to the gas turbine E as shown in FIG. This fuel supply device A includes an ammonia supply source 1, a booster pump 2, a heating device 3, a flow control valve 4, a first pressure gauge 5, a first thermometer 6, a second pressure gauge 7, and a control device 8. It is provided as a component. Among such components, the first pressure gauge 5, the first thermometer 6, the second pressure gauge 7, and the control device 8 constitute a supply control unit in the present invention.

  As is well known, the gas turbine E is a compressor that compresses air to generate combustion air (compressed air), and combusts ammonia N supplied from the fuel supply device A using the combustion air. A combustor for generating gas and a turbine for generating power using the combustion gas of the combustor are provided. The fuel supply device A according to the present embodiment supplies ammonia N as a gaseous fuel to the combustion chamber of the combustor.

  The ammonia supply source 1 supplies ammonia N to the booster pump 2. The ammonia supply source 1 is, for example, an ammonia tank for storing a predetermined volume of liquid ammonia in a pressurized state. The ammonia is discharged from the ammonia tank to be decompressed and vaporized, and supplied to the booster pump 2 as ammonia N (gas fuel). A dispensing device.

  The pressure increasing pump 2 increases the pressure of ammonia N supplied from the ammonia supply source 1 to a required pressure of the gas turbine E. The combustion chamber of the gas turbine E to which ammonia N is supplied as a gaseous fuel is in a high-temperature and high-pressure environment. (Supply pressure) must be higher than the pressure in the combustion chamber. In view of such circumstances of the gas turbine E, the booster pump 2 boosts the ammonia N within the predetermined allowable range (not less than the lower limit value Pmin and not more than the upper limit value Pmax) in which the supply pressure is set in advance. To supply.

  The heating device 3 is provided at an intermediate portion of a pipe connecting the booster pump 2 and the flow control valve 4, that is, upstream of the flow control valve 4, and based on a heating instruction input from the controller 8, the heating device 3 To heat the ammonia N supplied to the flow control valve 4. As the heating device 3, a device capable of heating the ammonia N with a high response to the above-mentioned heating instruction, that is, a device excellent in the heat response is preferable, for example, an electric heater.

  The flow control valve 4 is a control valve that adjusts the opening based on the opening instruction input from the control device 8 and feeds back a measured value of the opening (a measured value of the opening) to the control device 8. . The flow control valve 4 has a predetermined flow coefficient as an amount indicating the passage performance for ammonia N (passing fluid). Such a flow control valve 4 is an electromagnetic valve whose opening degree changes within a predetermined range when a valve body is driven by a DC motor, for example.

  Here, the passage performance of a valve such as the flow control valve 4 is generally indicated by a flow coefficient. There are several types of the flow coefficient, such as an effective area, a Cv value, and a Kv value. In the present embodiment, the performance of the flow control valve 4 is indicated by the Cv value. This Cv value is defined for water, which is originally liquid, but for a gas such as ammonia N, for example, is defined by the following equation (1).

In this equation (1), “Q” is a reference temperature of ammonia N passing through the flow control valve 4, a volume flow rate at the reference temperature (m ³ / h), “k” is a coefficient, and “d” is ammonia. The specific gravity of N, “T ₁ ” is the temperature (° C.) of ammonia N on the upstream side (primary side) of the flow control valve 4, and “P ₁ ” is the pressure (MPa) of ammonia N on the upstream side (primary side). , “P ₂ ” is the pressure (MPa) of ammonia N on the downstream side (secondary side) of the flow control valve 4. That is, the relationship between the volume flow rate Q, the upstream pressure P ₁ , the upstream temperature T ₁ , and the downstream pressure P ₂ of the ammonia N passing through the flow control valve 4 is defined by Expression (1).

Further, such a flow control valve 4 changes the flow rate of the ammonia N by changing the opening degree in a certain range. That is, the Cv value of the flow control valve 4 changes within a predetermined range according to the opening degree. The relationship (opening characteristic) between the flow rate, the opening, and the Cv value in the flow control valve 4 and the above equation (1) are stored in the control device 8 in advance as characteristic information of the flow control valve 4. Note that the coefficient k in the above equation (1) is “4140” under the condition of the differential pressure of P ₂ > P _1/2 .

The first pressure gauge 5 detects the pressure (MPa) of ammonia N on the upstream side (primary side) of the flow control valve 4, that is, the upstream pressure P ₁ in Expression (1), and outputs the detected pressure to the control device 8. The first thermometer 6 detects the temperature (° C.) of the ammonia N on the upstream side (primary side), that is, the upstream temperature P ₁ in Expression (1), and outputs the detected temperature to the control device 8. The second pressure gauge 7 detects the pressure (MPa) of ammonia N on the downstream side (secondary side) of the flow control valve 4, that is, the downstream pressure P ₂ in Expression (1), and outputs the detected pressure to the control device 8.

Here, ammonia N, which is a gaseous fuel of the present embodiment, has a boiling point of about −33 ° C. and is a gaseous inorganic compound at normal temperature and normal pressure. Ammonia N having such physical properties is liquefied at normal temperature (20 ° C.) under a pressure of about 0.857 MPa (8.46 atm), so that transportation and storage costs are low, and carbon (C) is used as a constituent element. Because it does not contain it, it is attracting attention as a fuel that does not emit carbon dioxide (CO ₂ ) by combustion.

  Since such ammonia N has a higher latent heat of vaporization than fuel of a general gas turbine E, it is difficult to burn when supplied to a combustion chamber as a liquid (liquid fuel). Preferably, it is supplied to the chamber. However, when ammonia N is supplied to the gas turbine E as a gaseous fuel because it has the above-described properties, the ammonia N is located downstream of the flow control valve 4 (2) where pressure loss locally occurs in the supply path. There is a possibility of re-liquefaction in the following side).

The control device 8 controls the overall operation of the fuel supply device A, and is a software control for automatically controlling the booster pump 2, the heating device 3, and the flow control valve 4 based on a control program stored in an internal memory in advance. Device. More specifically, the control device 8 controls the upstream pressure P ₁ , the upstream temperature T _1, and the downstream pressure input from the first pressure gauge 5, the first thermometer 6, and the second pressure gauge 7 described above. receiving the pressure P ₂ as a control amount, processing the control amount with a predetermined algorithm based on the required flow rate which is inputted from the characteristic information and an external pre-stored flow rate control valve 4 of the characteristic information and ammonia N in the internal memory Thus, the respective operation amounts of the booster pump 2, the heating device 3, and the flow control valve 4 are calculated.

  The control device 8 stores in advance the characteristic information of the ammonia N in addition to the characteristic information of the flow control valve 4 described above. The characteristic information of the ammonia N indicates a saturated vapor pressure curve of ammonia as a substance, that is, a phase state (a gas phase or a liquid phase) of the ammonia according to the temperature and the pressure.

  The required flow rate is input from outside the fuel supply device A, and the outside is, for example, an engine control device that comprehensively controls the operation of the gas turbine E. The control device 8 in the fuel supply device A controls the supply amount of ammonia N (gas fuel) to be supplied to the gas turbine E based on the required flow rate instructed by the engine control device, which is the host control system.

  It should be noted that the control device 8 and the first pressure gauge 5, the first thermometer 6, and the second pressure gauge 7 are configured to supply ammonia N (gas fuel) in accordance with a required flow rate input from the outside. Supply control means for setting the opening of the flow control valve 4 after adjusting the upstream pressure of the flow control valve 4 and, if necessary, the upstream temperature so as not to liquefy on the downstream side of the flow control valve 4. ing. That is, the fuel supply device A configured for this purpose is a device that supplies ammonia N (gas fuel) to the gas turbine E (predetermined location) via the flow control valve 4.

  Next, the operation of the fuel supply device A will be described in detail with reference to FIGS. FIG. 2 is a flowchart illustrating a procedure of the ammonia N supply control process performed by the control device 8. The fuel supply device A according to the present embodiment automatically controls the boosting pump 2, the heating device 3, and the flow control valve 4 according to the processing procedure of this flowchart.

  The fuel supply device A supplies ammonia N to the gas turbine E as a gaseous fuel, and therefore has a sufficient margin (pressure margin and pressure margin) for the state of ammonia N (pressure P and temperature T) so that ammonia N is not liquefied. Ammonia N must be supplied to gas turbine E in a state where the temperature margin is secured.

Therefore, the control unit 8, the supply amount of the ammonia N is supplied to the gas turbine as E (flow rate), the next request to the current request flow Q _n flow Q _{n + 1} is inputted (step S1), and the request The opening of the flow control valve 4 corresponding to the flow rate, that is, the next opening K _{n + 1} to be set instead of the current opening K _n , and the downstream pressure P ₂ and the downstream temperature T ₂ at the opening K _{n + 1} are estimated. (Step S2). Note that “n” is a subscript indicating time.

That is, the control device 8 determines the next opening Kn _{+ 1} and the Cv value _{Mn + 1 of} the flow control valve 4 corresponding to the next required flow Qn _{+ 1} based on the opening characteristic stored in advance as the characteristic information of the flow control valve 4. And Further, the control unit 8, the following Cv value M _{n + 1} and the required flow rate Q _{n + 1} and the first pressure gauge 5 and the upstream pressure P ₁ and the upstream temperature T ₁ of the formula inputted from the first thermometer 6 by substituting in (1), identifies a downstream pressure P ₂ corresponding to the next required flow rate Q _{n + 1.} Further, the control unit 8, by substituting the temperature-change due to the pressure change of the gas stored in advance the downstream pressure P ₂ as the control information, the downstream temperature T ₂ corresponding to the next required flow rate Q _{n + 1} To identify.

Then, the control device 8 determines whether or not the next opening degree K _{n + 1} specified in the process of step S2 is smaller than the current opening degree K _n , that is, whether or not to operate the flow control valve 4 in the closing direction. (Step S3). When the determination in step S3 is “Yes”, the controller 8 sets the state point of the ammonia N and the ammonia N on the downstream side of the flow control valve 4 when the flow control valve 4 is operated to the next opening degree _{Kn + 1} . The distance R from the saturated vapor pressure curve L is calculated (step S4). That is, as shown in FIG. 3, in the state space of the ammonia N including the pressure P and the temperature T, the control device 8 controls the downstream pressure P ₂ and the downstream temperature T ₂ corresponding to the next opening degree _{Kn + 1} . The shortest distance between the determined state point C _{n + 1} and the saturated vapor pressure curve L is calculated as the distance R.

Then, the control device 8 determines whether or not the ammonia N may be liquefied at the state point C _{n + 1} based on the distance R (step S5). That is, as shown in FIG. 3, the control device 8 determines whether the state point C _{n + 1} is located in the “liquid region” or the “gas region” of the ammonia N having the saturated vapor pressure curve L as a boundary line by the distance. R is determined based on R, it is determined that there is a possibility that ammonia N may be liquefied if it is located in the "liquid region" or if it is located in the "gas region" but the pressure margin and / or temperature margin is not sufficient If it is located in the "gas region" with a sufficient pressure margin and / or temperature margin, it is determined that there is no possibility that ammonia N is liquefied.

If the determination in step S5 is “Yes”, that is, if there is a possibility that the ammonia N may be liquefied at the state point C _{n + 1} , in order to eliminate the possibility, the discharge pressure of the booster pump 2, that is, the upstream pressure P ₁ Needs to be decompressed. That is, as shown in FIG. 3, when the state point C _{n + 1} is located in the “liquid region”, as one method, the downstream pressure P ₂ is reduced by lowering the upstream pressure P ₁ , and the state point C _{n + 1} is reduced. the it is possible to position in the same manner as "gas region" and the current state point C _n. From this viewpoint, the controller 8 calculates the upstream pressure P ₁ of the change value for distance the current state point C _n from the saturated vapor pressure curve L (pressure change value P _1a) (step S6).

On the other hand, if the determination in step S3 is "No", that is, if the next required flow rate Q _{n + 1} is a direction of requests to open the flow control valve 4, the control unit 8, the current upstream pressure P ₁ is sufficiently It is determined whether the pressure is set to an appropriate pressure (step S7). If the determination is “Yes”, the control device 8 operates the flow control valve 4 to the opening degree _{n + 1} corresponding to the next required flow rate Qn _{+ 1} (step S14). On the other hand, when the determination in step S7 is “No”, the control device 8 performs the process in step S6 to position the device in the “gas region” with a sufficient pressure margin and / or temperature margin. A change value (pressure change value P _1a ) of the upstream pressure P ₁ corresponding to the state point C _{n + 1} to be performed is calculated.

Here, as shown is Equation (1), changes in upstream pressure P ₁ (reduction) because involve changes of the flow rate Q a (reduced), so as to compensate for the change upstream pressure P ₁ (reduction) It is necessary to increase the Cv value _{Mn + 1} within the performance range of the flow control valve 4 (first constraint). Further, the upstream pressure P ₁ as described above is set lower limit Pmin and the upper limit value Pmax is the upstream pressure P ₁ is maintained the limit range defined by the lower limit Pmin and the upper limit Pmax (The second constraint).

Upstream pressure change value P _1a of the pressure P ₁ need to be determined under such first, second constraint. For example, as shown in FIG. 3, the upstream pressure if the current state point C _n on the downstream side is changed to the state point C _{n 'by} changing the P _1, the state point C _{n + 1} at the downstream state point C _{n + 1} '. In FIG. 3, the state point C _{n + 1} ′ is described as being located in the “liquid region”. However, depending on the position of the state point C _n with respect to the saturated vapor pressure curve L, the state point C _{n + 1} ′ is changed to the “gas region”. It is possible to be located.

Moreover, changing the upstream pressure P ₁ to a pressure change value P _1a, if the state point C _{n + 1 'is} located in the "liquid region" further corresponds is necessary in order to avoid liquefaction of ammonia N. That is, increase the downstream temperature T ₂ by raising the upstream temperature T ₁ (heating) is (heating), it is necessary to distance the current state point C _n from the saturated vapor pressure curve L I following. That is, as shown in FIG. 3, by raising the upstream temperature T ₁ of in addition to the step-down of the upstream pressure P _1, the state point C _{n + 1} located at the "liquid region"'to"gasregion" It is possible to set the located state point C _{n + 1} ".

Note that the rise in the upstream-side temperature T _1, it is necessary to increase the Cv value M _{n + 1} in the performance range of the flow rate control valve 4 to compensate for the change of the flow rate Q (reduction) associated therewith (a third constraint conditions). Further, it is necessary that the temperature does not exceed the heat resistance temperature (heat resistance temperature of equipment) of various devices shown in FIG. 1 (fourth constraint).

Now, the control device 8, in step S6, calculates the upstream pressure pressure change value P _1a of P ₁ in consideration of the first constraint. Then, the control device 8 determines whether or not the pressure change value _P1a satisfies a restriction range that is a second restriction condition (step S8). If the determination in step S7 is "Yes", the control device 8 determines the pressure change value _P1a as the next pressure set value (step S9), while the determination in step S7 is "No". In this case, the pressure change value _P1a is corrected so as to satisfy the limit range (step S10), and the corrected pressure change value _P1a is determined as the next pressure set value (step S9).

Then, the control device 8 calculates the distance R between the state point C _{n + 1} ′ corresponding to the pressure set value finally determined by the processing of steps S8 to S10 and the saturated vapor pressure curve L (step S11). Then, based on the distance R calculated in step S11, it is determined whether or not there is a possibility that ammonia N is liquefied at the state point C _{n + 1} ′ (step S12). Then, the control unit 8, if the determination in step S12 is "No", the upstream pressure P ₁ is set changes in pressure change value P _1a by adjusting the boost pump 2 (step S13), and on its The flow control valve 4 is adjusted to the opening corresponding to the required flow Qn _{+ 1} (step S14).

On the other hand, if the determination in step S12 is "Yes", if that is not prevent the liquefied ammonia N Changing the upstream pressure P ₁ to a pressure change value P _1a, the control unit 8, the upstream temperature T ₁ of the changing value (temperature change value _{T 1a)} calculates (step S15). That is, the control device 8 determines the temperature change value _T1a by considering the third constraint described above. Then, the control device 8 determines whether or not the temperature change value _T1a satisfies a device heat-resistant temperature which is a fourth constraint condition (step S16).

If the determination in step S16 is “Yes”, the controller 8 determines the temperature change value _T1a as the next temperature set value (step S17), while the determination in step S16 is “No”. In the case of ( ₁ ), the temperature change value _T1a is corrected so as to satisfy the equipment heat-resistant temperature (Step S18), and the corrected temperature change value _T1a is determined as the next temperature set value (Step S17). Then, after the processing in step S17, the control device 8 determines whether there is a possibility that the ammonia N may be liquefied (step S20).

Then, the control unit 8, if the determination in step S20 is "Yes", by repeating the process of step S6, further away the current state point C _n from the saturated vapor pressure curve L. On the other hand, the control device 8, when the determination in step S20 is "No", thereby setting change upstream temperature T ₁ of the temperature change value T _1a by raising the heating temperature of the ammonia N by the heating device 3 (Step S13).

According to the present embodiment, when the supply to the gas turbine E ammonia N (gaseous fuel), as required upstream pressure P ₁ and the upstream temperature T ₁ of, if the upstream pressure P ₁ or necessary Therefore, liquefaction (reliquefaction) of ammonia N (gas fuel) can be prevented.

Note that the present invention is not limited to the above embodiment, and for example, the following modified examples can be considered.
(1) In the above embodiment, ammonia N was used as the gaseous fuel, but the present invention is not limited to this. The present invention is applicable to liquid fuels other than ammonia N.

(2) In the above embodiment, when there is a possibility that ammonia N liquefies is the upstream pressure P ₁ is adjusted preferentially, the upstream temperature T ₁ of adjusted preferentially optionally Is also good. It is also possible to adjust only one of the upstream pressure P ₁ or the upstream temperature T _1.

(3) In the above embodiment, the Cv value was used as the flow coefficient, but the present invention is not limited to this. If necessary, the effective area or the Kv value may be used.

A fuel supply device E gas turbine N ammonia (gas fuel)
DESCRIPTION OF SYMBOLS 1 Ammonia supply source 2 Boost pump 3 Heating device 4 Flow control valve 5 First pressure gauge 6 First thermometer 7 Second pressure gauge 8 Control device

Claims (4)

A fuel supply device for supplying gaseous fuel to a predetermined location via a flow control valve,
After adjusting the upstream pressure and / or the upstream temperature of the flow control valve so that the gaseous fuel does not liquefy on the downstream side of the flow control valve according to the required flow rate input from the outside, the flow rate control is performed. A fuel supply device comprising a supply control means for setting an opening degree of a valve. The supply control means,
A first pressure gauge for detecting an upstream pressure of the flow control valve;
A first thermometer for detecting an upstream temperature of the flow control valve;
A second pressure gauge for detecting a downstream pressure of the flow control valve;
A control device for setting a change value of the upstream pressure based on the upstream pressure, the upstream temperature, the downstream pressure, a flow coefficient of the flow control valve, and a saturated vapor pressure curve of the gaseous fuel. The fuel supply device according to claim 1, wherein:   The supply control means sets a change value of the upstream pressure so that the gaseous fuel does not liquefy on the downstream side of the flow control valve within a predetermined allowable range set at the upstream pressure, and 3. The fuel supply device according to claim 1, wherein when the liquefaction of the gaseous fuel cannot be prevented by the change value, the upstream temperature is adjusted. 4. The fuel supply device according to any one of claims 1 to 3, wherein the gaseous fuel is ammonia, and the predetermined location is a combustion chamber of a gas turbine.

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