JP2020165382A - Control method for gas differential pressure power generation apparatus, gas differential pressure power generation apparatus, and control program therefor - Google Patents

Abstract

To provide a control method for a gas differential pressure power generation apparatus capable of generating power by directly controlling generation power based on a differential pressure of a fuel gas which occurs in regulating a pressure of the fuel gas to be supplied, the gas differential pressure power generation apparatus, and a control program therefor.SOLUTION: A control method for a gas differential pressure power generation apparatus 1 includes providing a threshold which is set correspondingly to output generated by a generator 30 or a valve opening of a flow control valve 10, within a power generation allowable zone as timing to change an expansion turbine 20 between a first expansion turbine 21 and a second expansion turbine 22, the expansion turbine to be operated within the power generation allowable zone defined as a flow band of urban gas in which power can be generated by the expansion turbine 20, in the flow bands of urban gas which can be distributed by a gas supply system 50.SELECTED DRAWING: Figure 1

Description

According to the present invention, for example, in a gas pressure regulating facility such as an LNG terminal or a governor station, gas differential pressure power generation is performed by utilizing the differential pressure of the generated fuel gas when adjusting the pressure of the supplied fuel gas. It relates to a control method of a device, a gas differential pressure power generation device, and a control program thereof.

City gas made from liquefied natural gas (LNG), which is a fuel gas, is supplied to customers through a conduit that communicates with a supplier such as an LNG terminal. Since the amount of city gas used varies depending on the size of the customer, the conduits are, in order from the supplier side, a high-pressure conduit for supplying to a large-scale customer and a high-pressure conduit for supplying to a medium-sized customer. The medium-pressure conduit and finally the low-voltage conduit for supplying to small-scale customers such as general households are connected in stages. Among the conduits, governor stations and the like are installed between the supply source and the high-pressure conduit, between the high-pressure conduit and the medium-pressure conduit, and between the medium-pressure conduit and the low-pressure conduit.

At the governor station, etc., the pressure of city gas is regulated, and the gas pressure regulator decompresses the primary pressure of the city gas on the supply source side, and the city gas on the secondary side is suitable for use on the demand side. The pressure is regulated. In addition, at governor stations and the like, power generation is performed using the differential pressure of the generated city gas as the pressure of the city gas is adjusted for the purpose of recovering the energy contained in the expanding city gas at the time of pressure adjustment. Sometimes. An example of the gas differential pressure type power generation device is disclosed in Patent Document 1.

Patent Document 1 supplies city gas with a governor that reduces the pressure on the primary side and regulates the pressure to a predetermined secondary side pressure, and an expansion turbine that expands the city gas from the primary side and reduces the pressure to the secondary side. It is a city gas differential pressure device with an energy recovery device connected in parallel in the system. In Patent Document 1, when the supply flow rate of city gas to the secondary side is detected and the supply flow rate of city gas changes in a flow rate band exceeding the minimum flow rate within a preset stable operating flow rate range in the governor. In the expansion turbine, the supply flow rate of city gas exceeding the minimum flow rate is flowed to the expansion turbine while following within a stable operating range and at a predetermined rate of change or less. By driving an expansion turbine supplied with city gas, a generator generates electricity to obtain electrical energy.

According to Patent Document 1, it is possible to effectively recover the energy (electrical energy) of the city gas by the pressure difference of the city gas while controlling the pressure on the secondary side to a stable state. The governor is said to respond to rapid changes in demand for city gas, and expansion turbines are said to recover electrical energy in response to gradual changes in demand.

Japanese Patent No. 35975552

Governor stations, etc. are provided in stages in the distribution process from the source of city gas to the destination of demand at multiple locations, and at any stage, the governor station, etc. regulates the pressure of a huge amount of city gas. Therefore, the amount of energy latent in city gas at the time of pressure regulation is very large. Therefore, since there is ample room for effective use of this energy, from the viewpoint of promoting energy saving, etc., we are trying to provide the market with the electric power obtained by utilizing the differential pressure of city gas at the time of pressure regulation. Then, quantitative and more precise management of electric energy becomes indispensable on the governor station or the like.

However, in such a case, in Patent Document 1, the drive of the expansion turbine is controlled based on the supply flow rate and pressure of the city gas flowing on the secondary side in the gas supply system, and the generated power is controlled. It is not something that is directly controlled. Therefore, it is difficult to more precisely control and adjust the electric power generated during the driving of the expansion turbine. Therefore, the technique of Patent Document 1 is not suitable for applications in which the amount of generated power is controlled and adjusted more accurately, power is supplied to the grid, and demand management is performed precisely.

The present invention has been made to solve the above-mentioned problems, and it is possible to directly control and generate power based on the differential pressure of the fuel gas generated when the pressure of the fuel gas to be supplied is adjusted. It is an object of the present invention to provide a control method of a gas differential pressure type power generation device, a gas differential pressure type power generation device, and a control program thereof.

The control method of the gas differential pressure type power generator, which is one aspect of the present invention made to solve the above problems, is a fuel distributed on a gas supply system that supplies fuel gas from a supply source side to a demand destination side. A governor that reduces the pressure on the primary side to regulate the pressure on the secondary side and an expansion turbine that reduces the pressure on the secondary side by expanding the fuel gas flowing from the primary side are arranged in parallel with the gas. The gas differential pressure type power generator connected to and connected to the above is provided with a control means for electrically controlling and a gas flow rate control means for controlling the flow of fuel gas flowing into the primary side of the expansion turbine. A plurality of expansion turbines are provided in a mode in which they are assembled with a generator to be connected, and the plurality of expansion turbines are connected to the gas supply system in a state of being connected in parallel, and are connected to at least the first expansion turbine. The said that the second expansion turbine is included, and the operation is performed within the power generation allowable region which is the flow zone of the fuel gas that can be generated by the expansion turbine in the flow band of the fuel gas that can be distributed in the gas supply system. As the timing for changing the expansion turbine, a threshold value set corresponding to at least one of the output generated by the generator and the valve opening degree of the gas flow rate control means is provided within the power generation allowable region. At the time of circulation of fuel gas, the control means controls the valve opening degree of the gas flow rate control means while acquiring the output value generated by the generator, and at the expansion turbine in operation, the threshold value is reached. When the state is reached, at least the first expansion turbine and the second expansion turbine are changed from the expansion turbine to be continuously operated with the threshold value as a boundary. ..

According to this aspect, in the gas differential pressure type power generation device according to the present invention, the electric power generated by the generator can be quantitatively and more precisely managed by the control means. Further, even if the amount of fuel gas used changes at the demand destination and the flow rate of the fuel gas flowing through the gas supply system fluctuates, for example, in a governor station or the like, the gas differential pressure type power generation device according to the present invention is pressure-regulated. The latent energy (electrical energy) of the fuel gas generated by the gas can be effectively recovered. Further, in the gas differential pressure type power generation device according to the present invention, the control means controls the power generation output of the generator of the expansion turbine in order to meet the power demand in line with the planned power generation value by controlling the gas flow rate control means. To adjust. Therefore, the gas differential pressure type power generation device according to the present invention can easily achieve the "simultaneous equal amount of planned values" for which a power generation plan is determined in advance.

In the above aspect, the first expansion turbine is capable of exerting the largest second maximum output within the range of the variable output of the generator of the second expansion turbine, whereas it is variable. It is preferable that the turbine is connected to the generator that includes the second maximum output within the output range and is capable of exerting a first maximum output larger than the second maximum output.

According to this aspect, even if the flow rate of the fuel gas flowing on the gas supply system fluctuates significantly, the energy of the city gas generated by the pressure regulation can be continuously recovered. In addition, the gas differential pressure power generation device according to the present invention has higher power generation efficiency and an output range with respect to the electric power generated based on the differential pressure of the fuel gas generated when the pressure of the supplied fuel gas is adjusted. It can generate electricity in a wider range.

In the above aspect, it is preferable that the gas flow rate control means is provided for the plurality of expansion turbines in a one-to-one combination with the individual expansion turbines.

According to this aspect, the plurality of expansion turbines can be operated under optimum conditions based on the individual gas flow control means.

In the above aspect, among the plurality of expansion turbines including the first expansion turbine and the second expansion turbine, the power generation is accompanied by the replacement of the expansion turbines that are operated with the threshold value as a boundary. When the machine continues to generate electricity, the control means starts the operation of the next expansion turbine to be newly operated in advance in accordance with the time when the threshold is reached, and is already in operation when the threshold is reached. It is preferable that the operation of the expansion turbine is stopped, and after the time when the threshold value is reached, the next expansion turbine starts to operate in a steady operation state with respect to the generator.

According to this aspect, when responding to fluctuations in the flow rate of fuel gas flowing through the gas supply system, power generation by the generator is performed by, for example, a generator of the first expansion turbine and a generator of the second expansion turbine. Even if the switch is made, when the threshold value is reached, the power generation output does not fluctuate significantly, and the power generation can be continued at the power generation output according to the flow rate of the fuel gas flowing through the gas supply system.

In the above aspect, the number of the expansion turbines to be operated is increased with respect to the plurality of expansion turbines including the first expansion turbine and the second expansion turbine, and the generator is generated. When the power generation is continued at, the control means starts the operation of the expansion turbine of the additional target to be newly operated in advance at the time when the threshold is reached, and after the time when the threshold is reached, the additional target of the additional target It is preferable that the expansion turbine starts to operate in a steady operating state with respect to the generator.

According to this aspect, even when the amount of fuel gas used increases at the demand destination and the flow rate of fuel gas flowing through the gas supply system increases, power is generated with a power generation output corresponding to the flow rate of fuel gas flowing through the gas supply system. You can continue.

In the above aspect, when the threshold value is reached, the gas flow rate control means causes the expansion turbine to be continuously operated by the gas flow rate control means based on the operating state of the expansion turbine to be added. It is preferable to control the flow rate of the fuel gas to be circulated.

According to this aspect, even if the number of generators increases due to the addition of the expansion turbine to be operated, the power generation output does not fluctuate significantly immediately after reaching the threshold value.

In the above aspect, among the plurality of expansion turbines including the first expansion turbine and the second expansion turbine, the number of the expansion turbines to be operated is reduced with respect to the threshold value to generate electricity. When the machine continues to generate electricity, the control means stops the operation of the expansion turbine to be reduced, which was in operation when the threshold is reached, and the continuation target which has been in operation since the threshold was reached. It is preferable that the expansion turbine is continuously operating in a steady operating state with respect to the generator.

According to this aspect, even when the amount of fuel gas used is reduced at the demand destination and the flow rate of fuel gas flowing through the gas supply system is reduced, power is generated with a power generation output corresponding to the flow rate of fuel gas flowing through the gas supply system. You can continue.

In the above aspect, when the control means reaches the threshold value, the fuel to be distributed to the expansion turbine to be continued by the gas flow rate control means based on the operating state of the expansion turbine to be reduced. It is preferable to control the flow rate of the gas.

According to this aspect, even if the number of generators is reduced by reducing the number of expansion turbines to be operated, the power generation output does not fluctuate significantly immediately after reaching the threshold value.

In the above aspect, the governor is opened when the flow rate of the fuel gas flowing in the power generation pipeline in which the plurality of expansion turbines are installed in the gas supply system exceeds the flow rate of the upper limit of the power generation allowable region. That is preferable.

According to this aspect, when the fuel gas satisfies the flow rate capable of generating power within the power generation allowable range and flows through the gas supply system in a large amount, the circulating fuel gas is used without waste and the generator efficiently generates power. The fuel gas that exceeds the upper limit of the permissible power generation area can be pressure-regulated by the governor and supplied to the demand destination side.

Further, the gas differential pressure type power generator, which is another aspect of the present invention made to solve the above problems, is distributed on a gas supply system that supplies fuel gas from the supply source side to the demand destination side. A governor that reduces the pressure on the primary side to the pressure on the secondary side with respect to the fuel gas, and an expansion turbine that reduces the pressure to the pressure on the secondary side by expanding the fuel gas flowing from the primary side. In the gas differential pressure type power generator connected in parallel, the expansion turbine has a plurality of expansion turbines in a form of being combined with a connected generator, and the plurality of expansion turbines are connected in parallel. In the state, it is connected to the gas supply system, and among the plurality of expansion turbines, at least the first expansion turbine and the second expansion turbine have the maximum output that can be generated by each of the generators. However, the control means includes a gas flow rate control means for controlling the flow of fuel gas flowing into the primary side of the expansion turbine and a control means for electrically controlling the expansion turbine, and the control means generates the power generator. The expansion turbine, which is electrically connected to the machine and the gas flow control means and includes at least one of the first expansion turbine or the second expansion turbine among the plurality of expansion turbines, is the gas. It is characterized in that it operates selectively based on the flow rate of the fuel gas controlled by the flow rate control means.

According to this aspect, even when the amount of fuel gas used changes at the demand destination and the flow rate of the fuel gas flowing through the gas supply system fluctuates, the gas supply does not cause a large fluctuation in the power output by the generator. Power can be generated with the power output according to the flow rate of fuel gas flowing through the system.

In the above aspect, it is preferable that the gas flow rate control means is provided for the plurality of expansion turbines in a one-to-one combination with the individual expansion turbines.

According to this aspect, the plurality of expansion turbines can be operated under optimum conditions based on the individual gas flow control means.

In the above aspect, it is preferable to provide a gas heating means for heating the fuel gas.

According to this aspect, even if the fuel gas is decompressed by the expansion turbine, the temperature of the fuel gas can be maintained at the temperature required for supply. Therefore, the fuel gas is continuously supplied after passing through the expansion turbine. When supplying to the downstream side of the system, it is possible to avoid hindering its operation.

Further, the control program of the gas differential pressure type power generator, which is another aspect of the present invention, has been made to solve the above problems, on the gas supply system for supplying fuel gas from the supply source side to the demand destination side. A governor that reduces the pressure on the primary side to the pressure on the secondary side with respect to the flowing fuel gas, and an expansion turbine that reduces the pressure on the secondary side by expanding the fuel gas flowing from the primary side. A control means that is connected in parallel and connected to perform electrical control, a storage means, and a gas flow rate control means that controls the flow of fuel gas flowing into the primary side of the expansion turbine. A plurality of expansion turbines are provided in a mode in which they are assembled with a generator to be connected, and the plurality of expansion turbines are connected to the gas supply system in a state of being connected in parallel, and among the plurality of expansion turbines. At least in the first expansion turbine and the second expansion turbine, the first expansion turbine exerts the largest second maximum output within the range of the output variable by the generator of the second expansion turbine. A gas differential pressure type connected to the generator that includes the second maximum output within a variable output range and can exhibit a first maximum output larger than the second maximum output. In the control program for the power generator, the expansion turbine is operated within the power generation allowable region which is the flow zone of the fuel gas that can be generated by the expansion turbine in the flow band of the fuel gas that can be distributed in the gas supply system. As the timing to change, a threshold value set corresponding to at least one of the output generated by the generator or the valve opening degree of the gas flow rate control means is provided in the power generation allowable region, and the flow of fuel gas. At that time, at least when the output generated by the generator is continuously acquired, the valve opening degree of the gas flow rate control means is controlled, and the expansion turbine in operation reaches the threshold value. The first expansion turbine and the second expansion turbine are characterized in that the expansion turbine that is continuously operated is changed with the threshold value as a boundary.

According to this aspect, the gas differential pressure type power generation device which is the target of the control program of the gas differential pressure type power generation device according to the present invention is automatically operated based on the flow of fuel gas flowing on the gas supply system at the time of pressure adjustment. Power can be generated by the differential pressure of the generated fuel gas.

According to the control method of the gas differential pressure type power generation device, the gas differential pressure type power generation device, and the control program thereof according to the present invention, the generated power is directly converted based on the differential pressure of the fuel gas generated when the pressure of the fuel gas to be supplied is adjusted. It can be controlled to generate electricity.

It is a system diagram which shows the outline of the gas differential pressure type power generation apparatus which concerns on embodiment. It is a series of system diagrams from the supply source to the supply destination of city gas. For a plurality of expansion turbines configured in the gas differential pressure power generation device according to the embodiment, the relationship between the ratio of the flow rate to the rated flow rate and the ratio of the power generation output to the rated output of the generator for one expansion turbine. It is an illustrated graph. It is a time chart diagram concerning the control method of the gas differential pressure type power generation apparatus which concerns on embodiment, (a) is the relationship with the flow rate of gas flowing through a power generation line, and (b) is with the power generation output W2 of a second expansion turbine. (C) is the relationship with the power generation output W1 of the first expansion turbine, (d) is the relationship with the total power generation output (W1 + W2) of both expansion turbines, and (e) is the relationship with the second flow control valve. The relationship with the valve opening D2, (f) shows the relationship with the valve opening D1 of the first flow control valve, and (g) shows the relationship with the pressure of the gas flowing through the secondary side pipeline. It is a figure. It is a graph which showed the relationship between the power generation power supplied by the gas differential pressure type power generation apparatus which concerns on embodiment, and the power generation power plan value as an example.

Hereinafter, embodiments of a gas differential pressure power generation device, a gas differential pressure power generation device, and a control program thereof according to the present invention will be described in detail with reference to the drawings. The gas differential pressure power generation device according to the present invention is installed in, for example, an LNG terminal, a governor station, or a gas pressure regulating facility such as a factory having a facility for regulating fuel gas. Hereinafter, in the present embodiment, the governor The case where it is installed in a station will be described as a representative.

First, a series of distribution processes from the supply source to the supply destination of city gas will be briefly explained. FIG. 2 is a series of system diagrams from the supply source to the supply destination of city gas. As shown in FIG. 2, city gas (fuel gas) made from liquefied natural gas (LNG) or the like is supplied to the customer 57 through a gas supply system 50 communicating from a supply source 56 such as an LNG terminal. Will be done. Although not shown in FIG. 2, in the actual gas supply system 50, in addition to the governor station 60, there is a gas pressure regulating facility having a gas pressure regulating power generation facility in the factory, but this embodiment Then, for convenience of explanation, only the governor station 60 is shown in FIG. 2, and the reference of such a gas pressure regulating facility is omitted.

The amount of city gas used varies depending on the size of the demand destination. Therefore, the gas supply system 50 has a high-pressure conduit 53 for supplying to the large-scale demand destination 57A and a medium-pressure conduit 53 for supplying to the medium-scale demand destination 57B such as hospitals and entertainment facilities in order from the supply source 56 side. The 54 and the low-voltage conduit 55 for supplying to the small-scale customer 57C such as a general household are connected in stages. In the high pressure conduit 53, the pressure of the city gas is as high as 1.0 MPa or more. In the medium pressure conduit 54, the pressure of the city gas is a medium pressure of 0.1 MPa or more and less than 1.0 MPa, and in the low pressure conduit 55, it is a low pressure of less than 0.1 MPa.

Of the gas supply system 50, a governor station 60 is installed between the supply source 56 and the high pressure conduit 53, between the high pressure conduit 53 and the medium pressure conduit 54, and between the medium pressure conduit 54 and the low pressure conduit 55. Will be done. At the governor station 60, the city gas flowing through the gas supply system 50 reduces the pressure on the primary side, which is the supply source 56 side, and regulates the pressure to a pressure suitable for use on the demand destination 57 side, which is the secondary side. Further, at the time of pressure regulation, power generation is performed using the differential pressure of the generated city gas for the purpose of recovering the energy contained in the expanding city gas, and the gas differential pressure type power generation according to the present embodiment is used to generate the power generation. Device 1 is used.

As shown in FIG. 2, the gas differential pressure type power generation device 1 is provided at a plurality of governor stations 60. Specifically, the gas differential pressure type power generation device 1 is provided at the first governor station 61 located between the supply source 56 and the high pressure conduit 53. At the first governor station 61, the city gas flowing through the gas supply system 50 by the gas differential pressure type power generation device 1 is changed from a state where the pressure on the supply source 56 side (primary side) is higher than the pressure on the high pressure conduit 53 side to the high pressure conduit 53. The pressure is regulated to the high pressure state on the side (secondary side). Further, even in the area where the high-pressure conduit 53 is laid, the fourth governor station 64 is provided between the first governor station 61 and the large-scale customer 57A to regulate the pressure of the city gas flowing through the high-pressure conduit 53. It has been.

Further, the gas differential pressure type power generation device 1 is provided at the second governor station 62 located between the high pressure conduit 53 and the medium pressure conduit 54. At the second governor station 62, the city gas flowing through the gas supply system 50 is moved from the high pressure state on the high pressure conduit 53 side (primary side) to the inside of the medium pressure conduit 54 side (secondary side) by the gas differential pressure type power generation device 1. The pressure is adjusted to the pressure state. Further, even in the area where the medium pressure conduit 54 is laid, the fifth governor station 65 is provided between the second governor station 62 and the medium-scale customer 57B, and the pressure of the city gas flowing through the medium pressure conduit 54 is regulated. Is being done.

Further, the gas differential pressure type power generation device 1 is provided at the third governor station 63 located between the medium pressure conduit 54 and the low voltage conduit 55. At the third governor station 63, the city gas flowing through the gas supply system 50 is moved from the medium pressure state on the medium pressure conduit 54 side (primary side) to the low pressure conduit 55 side (secondary side) by the gas differential pressure type power generation device 1. The pressure is adjusted to a low pressure state.

In the present embodiment, at the first governor station 61, the pressure of the city gas was adjusted with respect to the primary side from a state higher than the pressure on the high pressure conduit 53 side to a high pressure state on the secondary side. At the second governor station 62, the city gas was regulated from the high pressure state on the primary side to the medium pressure state on the secondary side. At the third governor station 63, the city gas was regulated from the medium pressure state on the primary side to the low pressure state on the secondary side. However, when adjusting the pressure of city gas at the governor station 60, the pressure adjustment conditions such as the pressure on the primary side, the pressure on the secondary side, and the pressure difference between the primary side and the secondary side are actually required in the on-site equipment. It suffices as long as it satisfies the pressure regulation condition of the city gas, and can be changed as appropriate.

Next, the outline of the gas differential pressure type power generation device will be described with reference to FIG. FIG. 1 is a system diagram showing an outline of a gas differential pressure type power generation device according to an embodiment. As shown in FIG. 1, the gas differential pressure type power generation device 1 includes a power generation line 5, a governor 9, a plurality of flow rate control valves 10 (gas flow rate control means), a shutoff valve 15, and a plurality of pressure gauges 16. Expansion turbine 20, heat exchanger 35 (gas heating means), control unit 2 (control means), storage unit 3 (storage means), generator 30, first power meter 36 and second power meter. It has 37 mag. Both the flow control valve 10 and the expansion turbine 20 are two in this embodiment. The governor 9 is installed on the main pipe of the gas supply system 50, reduces the pressure on the primary side flowing through the primary side gas supply system 51 to the city gas flowing through the gas supply system 50, and reduces the pressure on the primary side to the secondary side gas supply system 52. Adjust to the pressure on the secondary side that flows through.

When city gas generates power through the power generation line 5, if the city gas is flowing through the gas supply system 50 at a sufficient flow rate and the city gas flow becomes surplus for the power generation line 5, the governor is used. No. 9 opens, the city gas is also flowed over the main pipe of the gas supply system 50, and the excess city gas is regulated by the governor 9. On the contrary, the governor 9 may be open in the absence of surplus city gas.

First, the gas piping system of the gas differential pressure type power generation device 1 will be described. The power generation line 5 in which the two expansion turbines 20 are installed is connected in parallel with the governor 9 and communicates with the branch pipe forming a part of the gas supply system 50. The power generation pipeline 5 includes a primary side pipeline portion 6, a parallel pipeline portion 7, and a secondary side pipeline portion 8. Specifically, of the power generation pipeline 5, the primary side pipeline portion 6 is connected and communicated with the primary side gas supply system 51 in parallel, and the secondary side pipeline portion 8 is the secondary side gas. It is connected and communicated with the supply system 52 in parallel. The parallel pipeline portion 7 is formed by connecting the pipelines of a plurality of systems (two systems in this embodiment) in parallel according to the number of expansion turbines 20 and the like to be configured, and is formed by connecting the primary side pipeline portion 6 and the secondary side. It is connected in series with the pipeline portion 8.

In the present embodiment, a heat exchanger 35 is provided in the primary side pipeline portion 6 as a gas heating means for heating the city gas flowing through the parallel pipeline portion 7. Further, a shutoff valve 15 is provided in the primary side pipeline portion 6 in series with the heat exchanger 35 to allow or completely shut off the flow of city gas flowing through the primary side pipeline portion 6. It is a valve. The pressure gauge 16 measures the pressure of the city gas flowing through the secondary side pipeline portion 8.

The two expansion turbines 20 (first expansion turbine 21, second expansion turbine 22) are installed in the parallel pipeline portion 7. Specifically, one expansion turbine 20 is installed in each pipeline of the parallel pipeline portion 7, and in the parallel pipeline portion 7, the first expansion turbine 21 and the second expansion turbine 22 are connected in parallel. ing. Both of the two expansion turbines 20 are configured in a manner in which they are assembled with a generator 30 to be connected. The expansion turbine 20 reduces the pressure on the primary side by expanding the city gas flowing from the primary gas supply system 51 to the pressure on the secondary side of the city gas flowing through the secondary gas supply system 52. Along with adjusting the pressure, the generator 30 can generate power by rotating the turbine based on the flow of city gas.

Next, the generator 30 of the expansion turbine 20 will be described. In the governor station 60 (first governor stations 61 to 5th governor stations 65), the maximum output W1max that can be generated by the first generator 31 of the first expansion turbine 21 is the second generator 32 of the second expansion turbine 22. It is larger than the maximum output W2max that can generate electricity. As an example, the capacity such as the output of the generator 30 to be installed differs depending on the distribution conditions of the city gas actually regulated at the site, but the gas differential pressure type power generation device 1 installed at the first governor station 61 In the case of, as the output of the generator 30 (first generator 31, second generator 32), for example, the output W1 that can be generated by the first generator 31 is a maximum of 300 kW (W1max), and the second generator 32. The maximum output W2 that can be generated by the above is 125 kW (W2max) or the like.

That is, the second expansion turbine 22 is connected to the generator 32 capable of exhibiting the largest second maximum output W2max within the range of the variable output W2. With respect to the second expansion turbine 22, the first expansion turbine 21 includes the second maximum output W2max within the range of the variable output W1 and can exhibit the first maximum output W1max larger than the second maximum output W2max. It is connected to the generator 31.

FIG. 3 shows the ratio of the flow rate to the rated flow rate and the ratio of the power generation output to the rated output of the generator for each expansion turbine of the plurality of expansion turbines configured in the gas differential pressure power generation device according to the embodiment. It is a graph exemplifying the relationship with. In the expansion turbine 20, the rated flow rate of city gas that can flow in from the primary side is larger in the first expansion turbine 21 than in the second expansion turbine 22. On the other hand, in the first expansion turbine 21 and the second expansion turbine 22, the ratio of the flow rate of the city gas actually flowing in from the primary side to the rated flow rate of each is 40% or more, as shown in FIG. Then, in both the first expansion turbine 21 and the second expansion turbine 22, the flow rate of the city gas flowing in from the primary side becomes the power generation allowable region PB described later. The generator 30 of the first expansion turbine 21 and the second generator 32 of the second expansion turbine 22 generate power under the flow rate of city gas in the power generation allowable region PB.

The output generated by the generator 30 (first generator 31, second generator 32) is, for example, power supply to an external market, a destination for use at the installation location of the governor station 60, or the like. It is transmitted to the first 40. Alternatively, when transmitting power to the power supply destination 40, the power is temporarily stored in a storage battery or the like.

Next, the flow rate control valve 10 and the like will be described. The flow rate control valve 10 is a valve that controls the flow of city gas flowing into the primary side of the expansion turbine 20. The flow rate control valve 10 is installed in each of the two expansion turbines 20 in a one-to-one combination with one expansion turbine 20. Both of the two flow rate control valves 10 (the first flow rate control valve 11 and the second flow rate control valve 12) are provided in the parallel pipeline portion 7.

Specifically, in the first line (upper line in FIG. 1) of the parallel line section 7, the first flow control valve 11 is connected in series with the primary side of the first expansion turbine 21. It is paired with the first expansion turbine 21 in a one-to-one relationship. Further, in the second pipeline (lower pipeline in FIG. 1) of the parallel pipeline portion 7, the second flow rate control valve 12 is connected in series with the primary side of the second expansion turbine 22, and is second. It is paired with the expansion turbine 22 in a one-to-one relationship.

By the way, when the city gas circulates in the expansion turbine 20, the temperature of the city gas drops when the city gas expands with decompression. If the cold city gas is supplied to the downstream side of the gas supply system 50 after passing through the expansion turbine 20, the operation of the city gas flowing through the gas supply system 50 is hindered due to the cold city gas. There is a risk of causing it. In order to prevent such a phenomenon, a heat exchanger 35 is provided on the primary side of the expansion turbine 20, and the temperature of the city gas is raised in advance by the heat exchanger 35. In addition to the heat exchanger 35, the gas heating means may be, for example, a heater or the like, as long as it can heat the city gas that flows through the primary side pipeline portion 6 and flows into the primary side of the expansion turbine 20. The heat exchanger 35 is not particularly limited. Further, the position where the gas heating means such as the heat exchanger 35 is provided is the primary side of the power generation line 5 as long as it is a line capable of heating the city gas that has passed through the expansion turbine 20. It is not limited to the pipeline portion 6.

Next, the electric wiring system of the gas differential pressure type power generation device 1 will be described. The control unit 2 includes a storage unit 3, a first flow control valve 11, a second flow control valve 12, a shutoff valve 15, a wattmeter 16, a first generator 31 of the first expansion turbine 21, and a first. The second generator 32 of the two expansion turbines 22, the first wattmeter 36, the second wattmeter 37, a temperature sensor (not shown), and the like are electrically connected to each other. The control unit 2 is roughly divided into a control unit, a calculation unit, and a storage unit 3, and includes a known microcomputer (not shown) including a central processing unit (CPU), a memory, and the like.

The memory of the storage unit 3 stores a control program for the gas differential pressure type power generation device 1 for automating the power generation by the control method of the gas differential pressure type power generation device 1 described later. In this control program, among the flow zones of city gas that can be distributed in the gas supply system 50, the expansion turbine 20 to be operated is changed in the power generation allowable region PB that is the flow zone of city gas that can be generated by the expansion turbine 20. As the timing for this, the output W generated by the generator 30 or the threshold value TP set corresponding to the valve opening D of the flow control valve 10 is provided in the power generation allowable region PB. When the city gas is circulated, the power generation output W of the generator 30 is continuously acquired, the valve opening D of the flow control valve 10 is controlled, and the expansion turbine 20 in operation reaches the threshold value TP. Taking this opportunity, the expansion turbine 20 to be continuously operated is changed for the first expansion turbine 21 and the second expansion turbine 22 with the threshold value TP as a boundary.

Further, in the memory of the storage unit 3, the first power meter 36 detects the power generation output W1 of the first generator 31, and the second power meter 37 detects the power generation output W2 of the second generator 32. Then, by feeding back these detected values to the control unit 2, a program necessary for automatically selecting the generator 30 of the expansion turbine 20 to be operated is stored. In addition, a program required to automatically select the generator 30 of the expansion turbine 20 to be operated by feedforwarding the planned amount of generated power is stored. Further, as shown in FIG. 4 (g), the flow rate control valve 10 (by feeding back the pressure value detected by the pressure gauge 16 to the control unit 2 so that the pressure of the secondary side pipeline portion 8 becomes constant). A program necessary for automatically controlling the valve opening D of the first flow rate control valve 11 and the second flow rate control valve 12) is stored. In addition, a program for measuring the temperature of city gas with a thermometer (not shown), a program for controlling automatic opening and closing of a solenoid valve (not shown), and other programs are stored in advance. Further, in the memory of the storage unit 3, as an operation reference of the shutoff valve 15, the city gas flowing through the power generation line 5 is regarded as an abnormal state due to, for example, an excessive flow rate, an excessive pressure, an excessive temperature, or the like. The set value, the set value of the pressure after pressure adjustment detected by the pressure gauge 16, and the like can be stored.

Based on the control program stored in the storage unit 3, the control unit 2 controls the valve opening degree of the flow control valve 10, operates the expansion turbine 20, and controls the output generated by the generator 30. Performs electrical control on electrical components and control equipment. In the gas differential pressure power generation device 1, of the two expansion turbines 20, the first expansion turbine 21 or the second expansion turbine 22 selectively selects the flow rate of city gas controlled by the flow control valve 10. Operate.

Next, the control method of the gas differential pressure type power generation device 1 according to the present embodiment will be described with reference to FIG. FIG. 4 is an exemplary time chart diagram per day when supplying city gas to a demand destination with respect to the control method of the gas differential pressure type power generation device according to the embodiment. FIG. 4A is a diagram showing the relationship with the flow rate of gas flowing through the power generation line. The time chart shown in FIG. 4 is merely an example for convenience of explanation, and the behavior of the graph may differ from the actual distribution mode of the supplied city gas.

The flow rate of city gas circulating in the gas supply system 50 corresponds to the amount of city gas used at the demand destination 57. As shown in FIG. 4A, during the day when the amount of city gas used is relatively low, for example, the first time zone I such as early morning when human activity is relatively low, or the activity is completed. This is the fifth time zone V, etc., such as midnight when the person went to bed. The time zone in which the amount of city gas used increases most is, for example, the third time zone III such as the daytime when human activity is active. Further, the second time zone II in the middle from the first time zone I to the third time zone III is a time zone in which the amount of city gas used tends to gradually increase from the first time zone I. On the contrary, the fourth time zone IV, which is in the middle from the third time zone III to the fifth time zone V, is a time zone in which the amount of city gas used tends to gradually decrease from the third time zone III. is there.

The control method of the gas differential pressure type power generation device 1 according to the present embodiment is a power generation allowable region which is a flow zone of the city gas that can be generated by the expansion turbine 20 among the flow zones of the city gas that can be distributed by the gas supply system 50. As the timing to change the expansion turbine 20 to be operated in the PB, the threshold TP set corresponding to at least one of the output W generated by the generator 30 and the valve opening D of the flow control valve 10 is allowed to generate power. It is provided in the area PB. Further, in the control method of the gas differential pressure type power generation device 1, when city gas flows through the power generation line 5, the control unit 2 detects and acquires the output W generated by the generator 30, and the flow control valve 10 When the valve opening D of the above is controlled and the expansion turbine 20 in operation reaches the threshold value TP, the first expansion turbine 21 and the second expansion turbine 22 are separated from each other by the threshold value TP. , Change the expansion turbine 20 to be continuously operated.

Further, in the control method of the gas differential pressure type power generation device 1, the city gas supplied from the primary side gas supply system 51 of the gas supply system 50 is supplied from the gas supply system 50 through the power generation line 5 regardless of the opening and closing of the governor 9. , It circulates in the power generation allowable region PB and is pumped to the secondary gas supply system 52. The governor 9 may be closed while the city gas circulates in the power generation line 5 within the power generation allowable area PB. The control unit 2 constantly detects and acquires the power generation output W2 by the second generator 32 and the valve opening degree D2 of the second flow rate control valve 12. Further, the control unit 2 constantly detects and acquires the power generation output W1 by the first generator 31 and the valve opening degree D1 of the first flow rate control valve 11.

This will be described in detail. FIG. 4B is a diagram showing the relationship with the power generation output W2 of the second expansion turbine. FIG. 4C is a diagram showing the relationship with the power generation output W1 of the first expansion turbine. FIG. 4D is a diagram showing the relationship between the total power generation output (W1 + W2) of both expansion turbines. FIG. 4 (e) is a diagram showing the relationship with the valve opening degree D2 of the second flow rate control valve. FIG. 4 (f) is a diagram showing the relationship with the valve opening degree D1 of the first flow rate control valve. FIG. 4 (g) is a diagram showing the relationship with the pressure of the gas flowing through the secondary side pipeline portion. When changing two expansion turbines 20 (first expansion turbine 21 and second expansion turbine 22) in the control method of the gas differential pressure type power generation device 1 according to the present embodiment, "when replacing the expansion turbine 20". There are "when increasing the number of expansion turbines 20" and "when reducing the number of expansion turbines 20".

(1) When the expansion turbine 20 is replaced The generator 30 continues to generate electricity between the first expansion turbine 21 and the second expansion turbine 22 with the replacement of the expanding turbine 20 that operates at the threshold TP. At this time, the control unit 2 starts the operation of the next expansion turbine 20 to be newly operated in advance at the time when the threshold value TP is reached. At the same time as this start, when the threshold value TP is reached, the control unit 2 stops the operation of the expansion turbine 20 that has already been in operation. In the control unit 2, after the time when the threshold value TP is reached, the next expansion turbine 20 has started to operate with respect to the generator 30 in a steady operation state.

A specific description will be given with reference to FIG. First, when the expansion turbine 20 to be operated changes from the first time zone I to the second time zone II, in the first time zone I, the city gas is introduced into the second pipeline of the parallel pipeline portion 7 (in FIG. 1). , Lower pipeline), the second flow control valve 12 is circulated. The second expansion turbine 22 operates in the power generation allowable region PB based on the flow rate control of the city gas by the second flow rate control valve 12 (see FIG. 4B). On the other hand, the first expansion turbine 21 is stopped (see FIG. 4C). While the second expansion turbine 22 is in operation, the power generation output W2 of the second generator 32 approaches the second maximum output W2max of the threshold value TP1 (see FIG. 4B) (see the threshold value TP (TPU) in FIG. 3). ), The control unit 2 opens the valve opening D1 of the first flow rate control valve 11 as shown in FIG. 4 (f). As a result, the control unit 2 circulates the city gas through the first pipeline of the parallel pipeline portion 7 and starts the operation of the next expansion turbine 20 (first expansion turbine 21) to be newly operated in advance.

At the same time as the operation of the first expansion turbine 21, the control unit 2 closes the valve opening D2 of the second flow rate control valve 12 when the threshold value TP1 is reached, so that the parallel pipeline portion has been used so far. The flow of city gas flowing through the second pipeline of No. 7 is completely cut off. As a result, the control unit 2 stops the operation of the expansion turbine 20 (second expansion turbine 22) that has already been in operation, and stops the power generation by the second generator 32 (see FIG. 4B). Since the operation of the next expansion turbine 20 (first expansion turbine 21) has been started in advance and the first generator 31 has started power generation, the next expansion turbine 20 (first expansion) has been reached since the threshold TP1 was reached. As shown in FIG. 4C, the turbine 21) has started to operate in a steady operation state with respect to the generator 30 (first generator 31). Thus, between the first expansion turbine 21 and the second expansion turbine 22, the expansion turbine 20 that operates in the second time zone II alternates with the threshold value TP1 as a boundary. Therefore, even if the power generation by the generator 30 is switched from the second generator 32 to the first generator 31, the gas differential pressure type power generation device 1 causes a large fluctuation in the power generation output W when the threshold value TP1 is reached. It is possible to continue power generation with a power generation output W corresponding to the flow rate of city gas flowing through the power generation line 5.

Next, when the expansion turbine 20 to be operated changes from the 4th time zone IV to the 5th time zone V, in the 4th time zone IV, the city gas is supplied to the first pipeline of the parallel pipeline portion 7 (FIG. 1). The first flow control valve 11 is circulated through the middle and upper pipelines). The first expansion turbine 21 operates in the power generation allowable region PB based on the flow rate control of the city gas by the first flow rate control valve 11 (see FIG. 4C). On the other hand, the second expansion turbine 22 is stopped (see FIG. 4B). When the flow rate of city gas through the first flow rate control valve 11 gradually decreases during the operation of the first expansion turbine 21, the first expansion turbine 21 moves based on the flow rate control of the city gas by the first flow rate control valve 11. It approaches the threshold TP4 (see FIG. 4 (a)) (see the threshold TP (TPL) in FIG. 3), which causes the operation to be disabled in the power generation allowable region PB. The control unit 2 sets the valve opening D2 of the second flow rate control valve 12 in an open state as shown in FIG. 4 (e) at the time when the threshold value TP4 (see FIG. 4C) is reached. As a result, the control unit 2 circulates the city gas through the second pipeline of the parallel pipeline portion 7 and starts the operation of the next expansion turbine 20 (second expansion turbine 22) to be newly operated in advance.

At the same time as the operation of the second expansion turbine 22, the control unit 2 closes the valve opening D1 of the first flow rate control valve 11 when the threshold value TP4 is reached. The flow of city gas flowing through the first pipeline of No. 7 is completely cut off. As a result, the control unit 2 stops the operation of the expansion turbine 20 (first expansion turbine 21) that has already been in operation, and stops the power generation by the first generator 31 (see FIG. 4C). Since the operation of the next expansion turbine 20 (second expansion turbine 22) is started in advance and the second generator 32 is starting power generation, the next expansion turbine 20 (second expansion) 20 (second expansion) is started after the time when the threshold value TP4 is reached. As shown in FIG. 4B, the turbine 22) has started to operate in a steady operation state with respect to the generator 30 (second generator 32). Thus, between the first expansion turbine 21 and the second expansion turbine 22, the expansion turbine 20 that operates in the fifth time zone V alternates at the threshold value TP4. Therefore, even if the power generation by the generator 30 is switched from the first generator 31 to the second generator 32, the gas differential pressure type power generation device 1 causes a large fluctuation in the power generation output W when the threshold value TP4 is reached. It is possible to continue power generation with a power generation output W corresponding to the flow rate of city gas flowing through the power generation line 5.

(2) When increasing the number of expansion turbines 20 When increasing the number of expansion turbines 20 to be operated with respect to the first expansion turbine 21 and the second expansion turbine 22 at the threshold TP and continuing power generation by the generator 30. , The control unit 2 starts the operation of the expansion turbine 20 to be newly operated in advance according to the time when the threshold TP is reached, and after the time when the threshold TP is reached, the expansion turbine 20 to be added generates power. The machine 30 has begun to operate in a steady operating state. Further, when the threshold value TP is reached, the control unit 2 uses the flow rate control valve 10 to distribute the city gas to the expansion turbine 20 to be continuously operated based on the operating state of the expansion turbine 20 to be added. Control the flow rate.

A specific description will be given with reference to FIG. From the second time zone II to the third time zone III, when the amount of city gas used gradually increases and the flow rate of city gas flowing through the power generation line 5 increases, the operation is performed in the second time zone II. In the 1 expansion turbine 21, the power generation output W1 by the first generator 31 approaches the first maximum output W1max. The control unit 2 is shown in FIG. 4 (e) at the time when the threshold value TP2 (see FIG. 4 (c)) (see the threshold value TP (TPU) in FIG. 3) approaching the first maximum output W1max is reached. As described above, the valve opening degree D2 of the second flow rate control valve 12 is opened. As a result, the control unit 2 circulates the city gas through the second pipeline of the parallel pipeline portion 7 and starts the operation of the expansion turbine 20 (second expansion turbine 22) to be newly operated in advance. As shown in FIG. 4B, the expansion turbine 20 (second expansion turbine 22) to be added is in a steady operating state with respect to the generator 30 (second generator 32) after reaching the threshold value TP2. It is starting to operate at.

On the other hand, when the threshold value TP2 is reached, the control unit 2 has a flow control valve 10 (as shown in FIG. 4F) based on the operating state of the expansion turbine 20 (second expansion turbine 22) to be added. The valve opening D of the first flow rate control valve 11) is slightly reduced to reduce the flow rate of city gas flowing to the expansion turbine 20 (first expansion turbine 21) to be continuously operated by a predetermined amount. As a result, in the first expansion turbine 21, the power generation output W1 by the first generator 31 is slightly reduced as shown in FIG. 4C, but as shown in FIG. 4A, the power generation line 5 Since the flow rate of city gas flowing into the parallel pipeline portion 7 is increasing, the power generation output W2 by the second generator 32 of the second expansion turbine 22 is gradually increasing. Therefore, in the second time zone II, the power generation by the generator 30 is performed by the first generator 31 alone, and in the third time zone III, the second generator 32 is connected to the first generator 31. In addition, in the gas differential pressure type power generation device 1, the power generation output W does not fluctuate significantly immediately after reaching the threshold value TP2 even if the state is switched to the state of performing the power generation. Therefore, the gas differential pressure type power generation device 1 has a power generation output W (W1 + W2) corresponding to the flow rate of city gas flowing through the power generation line 5, and can continue power generation as shown in FIG. 4 (d). ..

(3) When reducing the number of expansion turbines 20 When the number of expansion turbines 20 to be operated is reduced with respect to the first expansion turbine 21 and the second expansion turbine 22 at the boundary of the threshold TP and the generator 30 continues to generate power. When the control unit 2 reaches the threshold TP, the operation of the expansion turbine 20 to be reduced, which has been operating, is stopped, and the expansion turbine 20 to be continuously operated after reaching the threshold TP generates power. The machine 30 is continuously operating in a steady operating state. Further, when the threshold value TP is reached, the control unit 2 controls the flow rate of the city gas to be distributed to the expansion turbine 20 to be continued by the flow rate control valve 10 based on the operating state of the expansion turbine 20 to be reduced. ..

A specific description will be given with reference to FIG. From the third time zone III to the fourth time zone IV, the amount of city gas used gradually decreases, and the flow rate of city gas flowing through the power generation line 5 decreases. In the present embodiment, the expansion turbine 20 to be reduced is preferentially the generator 30 having a small power generation output W with respect to the first expansion turbine 21 and the second expansion turbine 22 that are operated in the third time zone III. It is an expansion turbine 20 connected to. From the third time zone III to the fourth time zone IV, the amount of city gas used gradually decreases, and when the flow rate of city gas flowing through the power generation line 5 decreases, the second flow rate control is performed when the threshold value TP3 is reached. By closing the valve opening D2 of the valve 12, the flow of city gas that has been flowing through the second pipeline of the parallel pipeline portion 7 is completely shut off. As a result, the control unit 2 stops the operation of the expansion turbine 20 (second expansion turbine 22) to be reduced, which has been in operation, and stops the power generation by the second generator 32 (see FIG. 4B). On the other hand, the expansion turbine 20 (first expansion turbine 21), which has been in operation until now, is continuously operating in a steady operating state with respect to the generator 30 (first generator 31). ..

On the other hand, in the first expansion turbine 21, as shown in FIG. 4C, the power generation output W1 by the first generator 31 is reduced. When the threshold value TP3 is reached, the control unit 2 is a valve of the flow rate control valve 10 (first flow rate control valve 11), as shown in FIG. 4 (f), based on the operating state of the expansion turbine 20 to be reduced. The opening degree D is slightly widened, and the flow rate of the city gas distributed to the expansion turbine 20 (first expansion turbine 21) to be continuously operated is increased by a predetermined amount. As shown in FIG. 4 (a), the flow rate of the city gas flowing into the parallel pipeline portion 7 of the power generation pipeline 5 is reduced, and in the first expansion turbine 21, the first power generation is performed as shown in FIG. 4 (c). The power generation output W1 of the machine 31 tends to decrease. However, in the first expansion turbine 21, the power generation output W1 by the first generator 31 is reduced due to the increase in the valve opening D of the first flow control valve 11, due to the shutdown of the second expansion turbine 22 to be reduced. 2 The deficiency of the power generation output W2 by the generator can be absorbed. Therefore, in the third time zone III, the power generation by the generator 30 was performed by adding the second generator 32 to the first generator 31, and in the fourth time zone IV, the first generator 31 In the gas differential pressure type power generation device 1, the power generation output does not fluctuate significantly immediately after reaching the threshold value TP3 even if the state is switched to the state of performing the power generation by itself. Therefore, the gas differential pressure type power generation device 1 can continue power generation with a power generation output W (W1) corresponding to the flow rate of city gas flowing through the power generation line 5.

Next, the control method of the gas differential pressure type power generation device 1 according to the present embodiment, the gas differential pressure type power generation device 1, and the operation / effect of the control program thereof will be described.

The control method of the gas differential pressure type power generator 1 according to the present embodiment is on the primary side with respect to the city gas circulating on the gas supply system 50 that supplies city gas from the supply source 56 side to the demand destination 57 side. The governor 9 that reduces the pressure and regulates the pressure to the secondary side, and the expansion turbine 20 that reduces the pressure to the secondary side pressure by expanding the city gas flowing from the primary side are connected and connected in parallel. The gas differential pressure type power generator is provided with a control unit 2 for electrical control and a flow control valve 10 for controlling the flow of city gas flowing into the primary side of the expansion turbine 20, and the expansion turbine 20 includes. In this embodiment, the two expansion turbines 20 have two N = two and are connected to the gas supply system 50 in a state of being connected in parallel, in a mode in which the generator 30 is connected. Among the expansion turbines 20, in the first expansion turbine 21 and the second expansion turbine 22, the first expansion turbine 21 is the second largest within the range of the output variable by the second generator 32 of the second expansion turbine 22. While the maximum output W2max can be exhibited, the first generator that includes the second maximum output W2max within the variable output range and can exhibit the first maximum output W1max larger than the second maximum output W2max. An expansion turbine that is connected to 31 and is operated within the power generation allowable region PB that is the flow band of city gas that can be generated by the expansion turbine 20 among the flow bands of city gas that can be distributed by the gas supply system 50. As the timing for changing 20, a threshold value TP set corresponding to at least one of the output W generated by the generator 30 and the valve opening D of the flow control valve 10 is provided in the power generation allowable region PB. That is, when the city gas is circulated, the control unit 2 controls the valve opening D of the flow control valve 10 while acquiring the output W generated by the generator 30, and the expansion turbine 20 in operation has a threshold value TP. The first expansion turbine 21 and the second expansion turbine 22 are characterized in that the expansion turbine 20 that is continuously operated is changed with the threshold value TP as a boundary when the state reaches the above.

Due to this feature, even if the amount of city gas used changes at the demand destination 57 and the flow rate of city gas flowing through the power generation line 5 fluctuates significantly, at the governor station 60, the gas differential pressure type power generation device 1 is adjusted. The latent energy (electrical energy) of city gas generated by pressure can be continuously recovered. In addition, the gas differential pressure type power generation device 1 has higher power generation efficiency and a higher output range than the generated power W generated based on the differential pressure of the generated city gas when the pressure of the supplied city gas is adjusted. It can generate electricity in a wide range. Further, in the gas differential pressure type power generation device 1, the control unit 2 can quantitatively and more precisely manage the amount of electric power generated by the generator 30. In particular, from the viewpoint of promoting energy saving, etc., even when the electric power obtained by utilizing the differential pressure of city gas at the time of pressure regulation is provided to the market as the electric power supply destination 40 and sold, the gas differential pressure type power generation device. 1 can be easily applied to power sales that require "simultaneous equal amount of planned value" as an essential requirement, which has stricter control of the amount of electric power.

Here, the “simultaneous equal amount of planned values” will be described with reference to FIG. In the explanation, as illustrated above, the gas differential pressure type power generator 1 installed in the first governor station 61 uses the first generator 31 capable of generating a maximum of 300 kW (W1max) and a maximum of 125 kW (W2max). The case of the combination of the second generator 32 that enables power generation will be mentioned. FIG. 5 is a graph showing the relationship between the generated power supplied by the gas differential pressure type power generation device according to the embodiment and the planned power generation power generation value as an example.

When the electric power generated by the gas differential pressure type power generation device 1 is provided to the power supply destination 40, the gas differential pressure type power generation device 1 needs to generate electric power that satisfies the power generation plan value for which the power generation plan is determined in advance. In the gas differential pressure type power generation device 1 according to the present embodiment, the control unit 2 has a valve opening degree D of the first flow control valve 11 based on the power generation output W detected by the first power meter 36 and the second power meter 37. By controlling the valve opening D of the second flow control valve 12, the power generation output W of the generator 30 is controlled and adjusted in order to meet the power demand in line with the planned power generation value. Therefore, as shown in FIG. 5, the gas differential pressure type power generation device 1 can supply the generated power W to the power supply destination 40 in order to correspond to the planned power generation value, and therefore is indispensable for supplying the power supply destination 40. The requirement of "simultaneous planned value equal amount" can be easily achieved.

Further, in the control method of the gas differential pressure type power generation device 1 according to the present embodiment, the flow rate control valve 10 has an individual expansion turbine 20 for two expansion turbines 20 (first expansion turbine 21, second expansion turbine 22). It is characterized in that it is provided in a one-to-one pair with.

This feature allows the two expansion turbines 20 to operate under optimal conditions based on the individual flow control valves 10.

Further, in the control method of the gas differential pressure type power generation device 1 according to the present embodiment, the first expansion turbine 21 and the second expansion turbine 22 generate power by changing the expansion turbine 20 that operates at the threshold TP. When the machine 30 continues to generate electricity, the control unit 2 starts the operation of the next expansion turbine 20 to be newly operated in advance in accordance with the time when the threshold TP is reached, and is already in operation when the threshold TP is reached. The feature is that the operation of the previous expansion turbine 20 is stopped, and after the time when the threshold value TP is reached, the next expansion turbine 20 starts to operate with respect to the generator 30 in a steady operation state. ..

Due to this feature, when the amount of city gas used changes at the demand destination 57 and the fluctuation of the flow rate of city gas flowing through the power generation line 5 is coped with, the power generation by the generator 30 is performed by the first generator 31 and the second generator 31. Even if the generator 32 switches, when the threshold value TP is reached, the power generation output W does not fluctuate significantly, and power generation is continued at the power generation output W corresponding to the flow rate of the city gas flowing through the power generation line 5. Can be done.

Further, in the control method of the gas differential pressure type power generation device 1 according to the present embodiment, the number of expansion turbines 20 to be operated is increased with respect to the first expansion turbine 21 and the second expansion turbine 22 with the threshold value TP as a boundary to generate power. When the machine 30 continues to generate power, the control unit 2 starts the operation of the expansion turbine 20 to be newly operated in advance in accordance with the time when the threshold TP is reached, and after the time when the threshold TP is reached, the addition target is added. The expansion turbine 20 of the above is characterized in that it has started to operate in a steady operation state with respect to the generator 30.

Due to this feature, even when the amount of city gas used at the demand destination 57 increases and the flow rate of city gas flowing through the power generation line 5 increases, the power generation output W (W1 + W2) according to the flow rate of city gas flowing through the power generation line 5 ), The power generation can be continued.

Further, in the control method of the gas differential pressure type power generation device 1 according to the present embodiment, when the control unit 2 reaches the threshold value TP, the flow rate control valve 10 is used based on the operating state of the expansion turbine 20 to be added. It is characterized by controlling the flow rate of city gas to be distributed to the expansion turbine 20 to be continuously operated.

Due to this feature, even if the number of generators 30 to be operated increases due to the addition of the expansion turbine 20 to be operated, the power generation output W does not fluctuate significantly immediately after reaching the threshold value TP.

Further, in the control method of the gas differential pressure type power generation device 1 according to the present embodiment, the number of expansion turbines 20 to be operated in the first expansion turbine 21 and the second expansion turbine 22 is reduced with the threshold value TP as a boundary, and the generator is generated. When power generation is continued at 30, the control unit 2 stops the operation of the expansion turbine 20 to be reduced, which was in operation when the threshold value TP is reached, and the continuation target which has been in operation since the time when the threshold value TP is reached. The expansion turbine 20 of the above is characterized in that the generator 30 is continuously operated in a steady operating state.

Due to this feature, even when the amount of city gas used at the demand destination 57 is reduced and the flow rate of city gas flowing through the power generation line 5 is reduced, the power generation output W corresponding to the flow rate of city gas flowing through the power generation line 5 is obtained. It is possible to continue power generation.

Further, in the control method of the gas differential pressure type power generation device 1 according to the present embodiment, when the control unit 2 reaches the threshold value TP, the flow rate control valve 10 is used based on the operating state of the expansion turbine 20 to be reduced. It is characterized by controlling the flow rate of city gas to be distributed to the expansion turbine 20 to be continued.

Due to this feature, even if the number of generators 30 to be operated is reduced by reducing the number of expansion turbines 20 to be operated, the power generation output W does not fluctuate significantly immediately after reaching the threshold value TP.

Further, in the control method of the gas differential pressure type power generation device 1 according to the present embodiment, the city gas flowing in the power generation line 5 in which the two expansion turbines 20 are installed in the gas supply system 50 is the upper limit of the power generation allowable region PB. When the flow rate of the governor 9 is exceeded, the governor 9 is open.

Due to this feature, when the city gas satisfies the flow rate that can be generated in the power generation allowable area PB and flows through the gas supply system 50 in a large amount, the circulating city gas is used without waste and the generator 30 efficiently generates power. The city gas that exceeds the upper limit of the power generation allowable region PB is pressure-regulated by the governor 9 and can be supplied to the demand destination 57 side.

Further, the gas differential pressure type power generator 1 according to the present embodiment has a pressure on the primary side with respect to the city gas circulating on the gas supply system 50 that supplies the city gas from the supply source 56 side to the demand destination 57 side. The governor 9 that decompresses and regulates the pressure to the secondary side and the expansion turbine 20 that decompresses the pressure to the secondary side by expanding the city gas flowing from the primary side are connected in parallel. In the gas differential pressure type power generator, the expansion turbine 20 has two expansion turbines 20 (first expansion turbine 21, second expansion turbine 22) in a mode in which the expansion turbine 20 is assembled with the connected generator 30. Is connected to the gas supply system 50 in a state of being connected in parallel, and in the first expansion turbine 21 and the second expansion turbine 22, the magnitude of the maximum output W that can be generated by each generator 30 is large. The control unit 2 includes a flow control valve 10 for controlling the flow of city gas flowing into the primary side of the expansion turbine 20 and a control unit 2 for electrically controlling the flow control. The valve 10 and the generator 30 are electrically connected, and the first expansion turbine 21 and the second expansion turbine 22 are selectively operated based on the flow rate of city gas controlled by the flow control valve 10. It is characterized by doing.

Due to this feature, even when the amount of city gas used changes at the demand destination 57 and the flow rate of city gas flowing through the power generation line 5 fluctuates, the power generation output W by the generator 30 does not fluctuate significantly. Power can be generated with a power generation output W corresponding to the flow rate of city gas flowing through the power generation line 5.

Further, in the gas differential pressure type power generation device 1 according to the present embodiment, the flow rate control valve 10 is provided for two expansion turbines 20 in a one-to-one pair with each expansion turbine 20. It is a feature.

This feature allows the two expansion turbines 20 to operate under optimal conditions based on the individual flow control valves 10.

Further, the gas differential pressure type power generation device 1 according to the present embodiment is characterized in that the primary side pipeline portion 6 on the primary side of the expansion turbine 20 is provided with a heat exchanger 35 for heating city gas. ..

Due to this feature, when the city gas flowing through the parallel pipeline portion 7 of the power generation pipeline 5 is decompressed by the expansion turbine 20, the secondary side of the expansion turbine 20 is heated by anticipating a decrease in temperature due to expansion. It is possible to prevent the temperature of the flowing city gas from dropping significantly from the temperature before decompression. Therefore, even if the city gas is depressurized by the expansion turbine 20, the temperature of the city gas can be maintained at the temperature required for supply. Therefore, after passing through the expansion turbine 20, the city gas is continuously supplied to the gas supply system 50. It is possible to avoid hindering the operation of the supply when supplying it to the downstream side of.

Further, the control program of the gas differential pressure power generator 1 according to the present embodiment includes the expansion turbine 20 (first expansion turbine 21, second expansion turbine 22) in the flow band of city gas that can be distributed in the gas supply system 50. The output W generated by the generator 30 or the valve opening D of the flow control valve 10 is the timing to change the expansion turbine 20 to be operated in the power generation allowable region PB which is the flow band of the city gas capable of generating power. A threshold TP set corresponding to at least one of them is provided in the power generation allowable region PB, the output generated by the generator 30 is continuously acquired during the circulation of city gas, and the valve opening degree of the flow control valve 10 is obtained. When D is controlled and the expansion turbine 20 in operation reaches the threshold value TP, the first expansion turbine 21 and the second expansion turbine 22 are continuously operated with the threshold value TP as a boundary. It is characterized in that the expansion turbine 20 to be made to be changed is changed.

Due to this feature, the gas differential pressure type power generation device 1 can generate power by the differential pressure of the city gas generated at the time of pressure regulation by automatic operation based on the flow of the city gas flowing through the gas supply system 50.

Therefore, according to the control method of the gas differential pressure type power generation device 1 according to the present embodiment, the control program of the gas differential pressure type power generation device 1, and the gas differential pressure type power generation device 1, the city generated at the time of adjusting the pressure of the supplied city gas. Based on the differential pressure of the gas, the generated power can be directly controlled to generate power.

Although the present invention has been described above in accordance with the embodiments, the present invention is not limited to the above-described embodiments, and can be appropriately modified and applied without departing from the gist thereof.

(1) For example, in the control method of the gas differential pressure power generation device 1 according to the embodiment, when the number of expansion turbines 20 is reduced as the flow rate of city gas is reduced, expansion connected to a generator having a small power generation output is performed. Prioritizing the turbine, the second expansion turbine 22 having a small power generation output W2 was designated as the expansion turbine 20 to be reduced. However, the expansion turbine to be reduced may be the first expansion turbine 21 having a large power generation output W1, and is connected to a generator having no margin in the power generation allowable region according to the amount of decrease in the flow rate of city gas that actually occurs. Any expansion turbine will do.

(2) Further, in the embodiment, the gas differential pressure type power generation device 1 including two expansion turbines 20 (first expansion turbine 21 and second expansion turbine 22) is mentioned. However, the gas differential pressure power generation device of the present invention may include an expansion turbine in addition to the first expansion turbine and the second expansion turbine among the plurality of expansion turbines. The expansion turbine included in addition to the first expansion turbine and the second expansion turbine is the same as at least one of the first expansion turbine or the second expansion turbine, or the first expansion turbine and the second expansion turbine. It may be connected to a generator having a power generation output different from that of the above.

(3) Further, in the control method of the gas differential pressure type power generation device 1 according to the embodiment, the gas differential pressure type power generation device 1 is installed at the governor station 60. However, the gas differential pressure type power generation device of the present invention is installed not only at the governor station 60 but also at a gas pressure regulating facility such as a factory having a facility for regulating fuel gas, for example, in addition to the LNG terminal as described above. If the facility is a facility that uses the differential pressure of the generated fuel gas to generate power when adjusting the pressure of the supplied fuel gas, the installation location of the gas differential pressure power generation device of the present invention is It is not particularly limited.

1 Gas differential pressure type power generator 2 Control unit (control means)
3 Storage unit (memory means)
5 Power generation line 9 Governor 10 Flow control valve (gas flow control means)
11 First flow rate control valve (gas flow rate control means)
12 Second flow rate control valve (gas flow rate control means)
20 Expansion turbine 21 First expansion turbine (first expansion turbine)
22 Second expansion turbine (second expansion turbine)
30 Generator 31 First generator (generator)
32 Second generator (generator)
50 Gas supply system 56 Supply source 57 Demand destination PB Power generation allowable area W1max 1st maximum output W2max 2nd maximum output

Claims (13)

On the gas supply system that supplies fuel gas from the supply source side to the demand destination side, a governor that reduces the pressure on the primary side to the pressure on the secondary side with respect to the circulating fuel gas, and from the primary side A control means that electrically controls a gas differential pressure power generator connected in parallel with an expansion turbine that reduces the pressure to the secondary side pressure by expanding the circulating fuel gas, and the expansion. A gas flow control means for controlling the flow of fuel gas flowing into the primary side of the turbine is provided.
The expansion turbine has a plurality of expansion turbines in a form assembled with a connected generator, and the plurality of expansion turbines are connected to the gas supply system in a state of being connected in parallel, and at least the first expansion turbine. And include a second expansion turbine,
Among the flow zones of fuel gas that can be distributed in the gas supply system, the power generation is performed as a timing for changing the expansion turbine to be operated within the power generation allowable region that is the flow zone of the fuel gas that can be generated by the expansion turbine. A threshold value set corresponding to at least one of the output generated by the machine and the valve opening degree of the gas flow rate control means is provided within the power generation allowable region.
When the fuel gas is circulated, the control means controls the valve opening degree of the gas flow rate control means while acquiring the output value generated by the generator, and reaches the threshold value in the operating expansion turbine. When the state is reached, at least the first expansion turbine and the second expansion turbine are changed from the expansion turbine to be continuously operated with the threshold value as a boundary.
A control method for a gas differential pressure type power generator characterized by. In the control method of the gas differential pressure type power generation device according to claim 1,
The first expansion turbine is capable of exerting the largest second maximum output within the range of the variable output of the generator of the second expansion turbine, whereas the first expansion turbine is within the range of the variable output. Being connected to the generator that includes the second maximum output and is capable of exerting the first maximum output that is larger than the second maximum output.
A control method for a gas differential pressure type power generator characterized by. In the control method of the gas differential pressure type power generation device according to claim 1 or 2.
The gas flow rate control means is provided for the plurality of expansion turbines in a one-to-one pair with the individual expansion turbines.
A control method for a gas differential pressure type power generator characterized by. In the control method of the gas differential pressure type power generation device according to claim 2 or 3.
When the generator continues to generate electricity in the plurality of expansion turbines including the first expansion turbine and the second expansion turbine, with the expansion turbine being operated at the threshold value as a boundary. ,
The control means starts the operation of the next expansion turbine to be newly operated in advance in accordance with the time when the threshold value is reached, and when the threshold value is reached, the expansion turbine already in operation is started. Stop the operation of
After reaching the threshold value, the next expansion turbine has started to operate in a steady operating state with respect to the generator.
A control method for a gas differential pressure type power generator characterized by. In the control method of the gas differential pressure type power generation device according to claim 2 or 3.
When the number of the expansion turbines to be operated is increased with respect to the plurality of expansion turbines including the first expansion turbine and the second expansion turbine with the threshold value as a boundary and power generation is continued by the generator.
The control means starts the operation of the expansion turbine to be newly operated in advance at the time when the threshold value is reached.
After reaching the threshold value, the expansion turbine to be added has started to operate in a steady operating state with respect to the generator.
A control method for a gas differential pressure type power generator characterized by. In the control method of the gas differential pressure type power generation device according to claim 5.
When the control means reaches the threshold value, the flow rate of the fuel gas to be distributed to the expansion turbine to be continuously operated by the gas flow rate control means based on the operating state of the expansion turbine to be added. To control,
A control method for a gas differential pressure type power generator characterized by. In the control method of the gas differential pressure type power generation device according to claim 2 or 3.
When the number of the expansion turbines to be operated is reduced with the threshold value as a boundary among the plurality of expansion turbines including the first expansion turbine and the second expansion turbine, and power generation is continued by the generator. ,
When the threshold value is reached, the control means stops the operation of the expansion turbine to be reduced, which has been in operation.
The expansion turbine, which has been in operation since the time when the threshold value was reached, is continuously operating in a steady operating state with respect to the generator.
A control method for a gas differential pressure type power generator characterized by. In the control method of the gas differential pressure type power generation device according to claim 7.
When the threshold value is reached, the control means controls the flow rate of the fuel gas to be distributed to the expansion turbine to be continued by the gas flow rate control means based on the operating state of the expansion turbine to be reduced. thing,
A control method for a gas differential pressure type power generator characterized by. In the method for controlling a gas differential pressure power generation device according to any one of claims 1 to 8.
In the power generation line in which the plurality of expansion turbines are installed in the gas supply system,
When the flowing fuel gas exceeds the flow rate of the upper limit of the allowable power generation area, the governor is open.
A control method for a gas differential pressure type power generator characterized by. On the gas supply system that supplies fuel gas from the supply source side to the demand destination side, a governor that reduces the pressure on the primary side to the pressure on the secondary side with respect to the circulating fuel gas, and the primary side. In a gas differential pressure type power generation device in which an expansion turbine that reduces the pressure to the secondary side pressure by expanding the fuel gas flowing from the gas is connected in parallel.
The expansion turbine has a plurality of expansion turbines in a form assembled with a generator to be connected, and the plurality of expansion turbines are connected to the gas supply system in a state of being connected in parallel.
Of the plurality of expansion turbines, at least the first expansion turbine and the second expansion turbine have different maximum output sizes that can be generated by the generators.
A gas flow rate control means for controlling the flow of fuel gas flowing into the primary side of the expansion turbine, and
Equipped with control means for electrical control,
The control means is electrically connected to the generator and the gas flow rate control means.
Among the plurality of expansion turbines, the expansion turbine including at least one of the first expansion turbine or the second expansion turbine is selected based on the flow rate of the fuel gas controlled by the gas flow rate control means. To work
A gas differential pressure type power generator characterized by. In the gas differential pressure type power generation device according to claim 10.
The gas flow rate control means is provided for the plurality of expansion turbines in a one-to-one pair with the individual expansion turbines.
A gas differential pressure type power generator characterized by. In the gas differential pressure type power generation device according to claim 10 or 11.
Having a gas heating means to heat the fuel gas,
A gas differential pressure type power generator characterized by. On the gas supply system that supplies fuel gas from the supply source side to the demand destination side, a governor that reduces the pressure on the primary side to the pressure on the secondary side with respect to the circulating fuel gas, and from the primary side A control means, a storage means, and a primary expansion turbine that perform electrical control by connecting and connecting an expansion turbine that reduces the pressure to the secondary pressure by expanding the circulating fuel gas in parallel. A gas flow control means for controlling the flow of fuel gas flowing into the side is provided.
The expansion turbine has a plurality of expansion turbines in a form assembled with a generator to be connected, and the plurality of expansion turbines are connected to the gas supply system in a state of being connected in parallel, and the plurality of expansion turbines of the plurality of expansion turbines. Among them, at least in the first expansion turbine and the second expansion turbine, the first expansion turbine has the largest second maximum output within the range of the output variable by the generator of the second expansion turbine. The gas difference connected to the generator that includes the second maximum output within the variable output range and can exert the first maximum output larger than the second maximum output. In the control program for pressure generators,
Among the flow zones of fuel gas that can be distributed in the gas supply system, the power generation is performed as a timing for changing the expansion turbine to be operated within the power generation allowable region that is the flow zone of the fuel gas that can be generated by the expansion turbine. A threshold value set corresponding to at least one of the output generated by the machine and the valve opening degree of the gas flow control means is provided within the power generation allowable region.
When the fuel gas is circulated, the output generated by the generator is continuously acquired, the valve opening degree of the gas flow control means is controlled, and the expansion turbine in operation reaches the threshold value. To change the expansion turbine to be continuously operated at least with respect to the first expansion turbine and the second expansion turbine with the threshold value as a boundary.
A control program for a gas differential pressure power generator characterized by.

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