JP6530635B2 - Center device and water supply position identification method - Google Patents

Description

  The present invention relates to a center device that identifies the position of feed water that has entered a gas supply pipe for supplying gas.

  In order to grasp the passing volume of hydrocarbon gas consumed by the consumer, the gas company places a gas meter at the demand point and charges based on the passing volume of gas measured by the gas meter. ing. Here, if the calorific value per unit volume of the gas supplied to the demand point is constant, the calorific value of the gas passing through the gas meter based on the gas passing volume, that is, the gas consumed by the consumer The total calorific value can be derived accurately. Therefore, billing can be properly performed.

  However, gas with different calorific value may be supplied to the demand point depending on time and place. In such a case, it is difficult for the conventional gas meter to measure only the passing volume of gas based on the passing volume of gas, so it is difficult to correctly derive the amount of passing heat, and there is a risk that it may not be possible to charge appropriately. is there.

  Therefore, assuming that the gas supplied to the demand point is a hydrocarbon gas, the temperature and sound velocity of the gas are measured, and the calorific value in the standard state of the gas is estimated based on the measured temperature and sound velocity. There has been proposed a gas meter configured to derive a passing calorific value based on the estimated calorific value in the standard state, the passing volume of gas, and the temperature of the gas (for example, Patent Document 1).

JP, 2013-210344, A

  By the way, when feed water intrudes into a gas supply pipe for supplying gas, the feed water may block the gas supply pipe, which may cause trouble in supply of gas to a demand point.

  However, in the gas meter system including the conventional gas meter and the gas meter of Patent Document 1, it is specified that the feed water is invading the gas supply pipe and the position of the feed water until the gas pipe is completely blocked with water. There was a problem that I could not do it.

  An object of this invention is to provide the center apparatus which can pinpoint the position of the feed water which infiltrated into the gas supply pipe in view of such a subject, and a feed water position specifying method.

To solve the above problems, the center device of the present invention, supplying a sonic velocity of the gas supplied to each of the plurality of gas meters, gas information acquisition unit that acquires from each of the gas meter of the plurality, the gas to the plurality of gas meters Water supply position specifying unit for specifying the position of water supply in the gas supply pipe based on the difference in the sound velocity of the gas of the plurality of gas meters connected upstream and downstream of the gas in the gas supply pipe .

  Further, the gas may include a hydrocarbon-based gas.

The heat generation amount deriving unit is further configured to derive a heat generation amount of the gas used in the gas meter based on the sound velocity of the gas, and the heat generation amount derivation unit is configured of the feed water specified by the water supply position specifying unit. It is preferable to derive a calorific value obtained by subtracting the calorific value of the inflowing water vapor with respect to the gas meter connected downstream of the position .

In the method for specifying the position of the feed water according to the present invention, the sound velocity of the gas supplied to each of the plurality of gas meters is obtained from each of the plurality of gas meters, and the gas supply pipe for supplying the gas to the plurality of gas meters is obtained. The position of the feed water in the gas supply pipe is determined based on the difference in the sound velocity of the gas of the plurality of gas meters connected from upstream to downstream of the gas.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the center apparatus which can pinpoint the position of the feed water which infiltrated into the gas supply pipe | tube, and the feed water position locating method.

It is an explanatory view showing a rough composition about information transmission of a gas meter system. FIG. 2 shows a gas supply conduit network. It is a functional block diagram showing a schematic configuration of a gas meter. It is a figure showing composition of an ultrasonic flowmeter. It is a figure explaining the waveform of the ultrasonic wave received with the ultrasonic transmitter-receiver of an ultrasonic flowmeter. It is a functional block diagram showing a schematic configuration of a gas production plant. It is a functional block diagram showing a schematic structure of a center device. It is a figure explaining the time-sequential change of the sound velocity of gas. It is a figure explaining a gas supply map. It is a figure which shows the relationship between temperature, sound speed, and calorific value of gas. It is a figure which shows the relationship between sound speed and unit calorific value. It is a figure which shows the relationship of the temperature and the speed of sound in the case of nitrogen-containing gas in the case of hydrocarbon-based gas only and in the case of hydrocarbon-based gas. It is a figure for demonstrating the speed of sound in a gas meter in, when feed water has infiltrated into the gas supply pipe | tube. It is a functional block diagram showing a schematic configuration of a gas meter according to a modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values and the like shown in this embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the specification and the drawings, elements having substantially the same functions and configurations will be denoted by the same reference numerals to omit repeated description, and elements not directly related to the present invention will not be illustrated. Do.

(Gas meter system 100)
FIG. 1 is an explanatory view showing a schematic configuration regarding information transmission of the gas meter system 100. As shown in FIG. As shown in FIG. 1, the gas meter system 100 is configured to include a plurality of gas meters 110, a plurality of gateway devices 112, a plurality of gas production factories 114, and a center device 116.

  The gas meter 110 derives the speed of sound and the flow rate of the gas supplied to the demand point 120, and controls the device 122 installed at the demand point 120 according to a command from the center device 116. The gateway device 112 collects data for one or more gas meters 110 and also delivers data to one or more gas meters 110.

  The gas generating plant 114 generates a gas to be supplied to the demand point, and specifies a gas characteristic showing a relationship between the temperature of the generated gas, the speed of sound and the calorific value per unit volume (hereinafter also referred to as unit calorific value).

  The center apparatus 116 is configured by a computer or the like, and belongs to a manager of the gas meter system 100 such as a gas company. The center device 116 collects data of one or more gateway devices 112 and delivers data to one or more gateway devices 112. Therefore, the information possessed by the gas meters 110 disposed at all the demand points 120 can be collectively managed by the center device 116.

  Here, wireless communication is performed between the gateway device 112 and the center device 116 through an existing communication network such as a mobile phone network including the base station 118 or a Personal Handyphone System (PHS) network. Further, wireless communication is performed between the gas meters 110 and between the gas meter 110 and the gateway device 112 through, for example, a smart meter wireless system (U-Bus Air) using a 920 MHz band.

  Further, the center device 116 executes wired communication with the gas generating plant 114 through the existing communication network, and collects information (gas characteristics) of the one or more gas generating plants 114.

  FIG. 2 shows a gas supply conduit network 130. As shown in FIG. 2, the gas supply conduit network 130 is constituted by a plurality of gas meters 110 and a gas supply pipe 132 distributed to a plurality of gas production plants 114. In other words, the plurality of gas meters 110 and the plurality of gas production plants 114 are connected via the gas supply conduit network 130 (gas supply pipe 132).

  Then, the gases generated in the plurality of gas production plants 114 are supplied to the gas meter 110 through the gas supply pipes 132 constituting the gas supply conduit network 130. Therefore, although the gas generated in the plurality of gas production plants 114 is supplied to the gas supply conduit network 130, the movement by the gas transport in the gas pipe is dominant over the diffusion of the gas in the gas pipe. , The gases produced by the plurality of gas producing plants 114 are hardly mixed.

  On the other hand, in the gas meter 110, among the gases generated in the plurality of gas production plants 114, the gas produced in any of the gas production plants 114 is supplied. And even if it is the same gas meter 110, the generation origin (gas production factory 114) of the supplied gas, ie, the supplied gas, may differ depending on time.

  Therefore, in the gas meter system 100 according to the present embodiment, the configuration (the gas production plant 114) of the gas supplied to the gas meter 110 is specified by the configuration of the gas meter 110, the gas production plant 114 and the center device 116 described in detail below. , Accurately derive the unit calorific value of the gas passing through the gas meter 110. Then, when the feed water enters the gas supply pipe 132 for supplying the gas from the gas production plant 114 to the gas meter 110, it is possible to specify the position where the feed water has infiltrated in the gas supply pipe.

(Gas meter 110)
FIG. 3 is a functional block diagram showing a schematic configuration of the gas meter 110. As shown in FIG. The gas meter 110 includes an ultrasonic flowmeter 150, a shutoff valve 152, a communication circuit 154, a gas meter storage unit 156, and a gas meter control unit 158.

  FIG. 4 is a diagram showing the configuration of the ultrasonic flowmeter 150. As shown in FIG. The ultrasonic flowmeter 150 is an arrival time difference type flowmeter, and as shown in FIG. 4, two points, upstream and downstream, along the flow of the gas flow path 140 (indicated by white arrows in FIG. 4). And a pair of ultrasonic transmitters / receivers 150a, 150b disposed in one of the ultrasonic transmitters / receivers 150a, 150b to the other ultrasonic transmitter / receiver 150b, 150a. It can be measured bi-directionally at every unit time. The propagation times t1 and t2 are used by the sound velocity deriving unit 160 described later.

  Here, since the pair of ultrasonic transmitters / receivers 150a, 150b are disposed on the upstream side and the downstream side of the gas flow path 140, the ultrasonic waves propagating between the two are affected by the flow velocity of the gas and The ultrasonic wave propagated from the downstream side is accelerated, and the ultrasonic wave propagated from the downstream side to the upstream side is decelerated. Here, the propagation time of the ultrasonic wave propagated from the upstream ultrasonic transmitter-receiver 150a to the downstream ultrasonic transmitter-receiver 150b is t1, and the ultrasonic transmitter-receiver 150a upstream from the downstream ultrasonic transmitter-receiver 150b. The propagation time of the ultrasonic wave to be propagated to t.

  Returning to FIG. 3, the shutoff valve 152 is constituted by, for example, a solenoid valve or a solenoid valve using a stepping motor, and shuts off or opens the gas flow path. The communication circuit 154 establishes wireless communication with the gateway device 112 and other gas meters 110. The gas meter storage unit 156 includes a ROM, a RAM, a flash memory, an HDD, and the like, and stores programs and various data used for the gas meter 110.

  The gas meter control unit 158 is configured of a CPU and a DSP, and controls the entire gas meter 110 using a program stored in the gas meter storage unit 156. Further, the gas meter control unit 158 functions as a sound velocity deriving unit 160, a flow rate deriving unit 162, a blocking unit 164, and a meter communication unit 166.

  The sound velocity deriving unit 160 derives the sound velocity based on the propagation times t1 and t2 measured by the ultrasonic flow meter 150. The flow rate deriving unit 162 derives the flow rate of the gas based on the propagation times t1 and t2 measured by the ultrasonic flowmeter 150.

  The shutoff unit 164 controls the shutoff valve 152 to control the supply and demand of gas. The meter communication unit 166 exchanges information with the center apparatus 116 through the communication circuit 154, and, for example, the information on the sound velocity derived by the sound velocity deriving unit 160 and the flow rate derived by the flow rate deriving unit 162 can be transmitted to the center apparatus 116 every hour. Send. However, the present embodiment is also applicable to a configuration without the shutoff unit 164 and the shutoff valve 152.

  Hereinafter, detailed processing of the sound velocity deriving unit 160 and the flow amount deriving unit 162 will be described.

(Sound velocity deriving unit 160)
FIG. 5 is a diagram for explaining the waveform of the ultrasonic wave received by the ultrasonic transmitter-receivers 150a and 150b of the ultrasonic flowmeter 150. As shown in FIG. As shown in FIG. 5, the ultrasonic wave transmitted from the ultrasonic wave transmitter / receiver 150a or 150b of the ultrasonic flow meter 150 has a small amplitude immediately after the start of reception, and the amplitude gradually increases, and the amplitude after several cycles of wavelength Reaches its peak, and then the amplitude decreases again. When the ultrasonic transmitters / receivers 150a, 150b receive ultrasonic waves transmitted from the paired ultrasonic transmitters / receivers 150b, 150a, the first several circumferential wavelengths are small due to the problem of sensitivity and S / N ratio. It is difficult to define the arrival time of the wave with high accuracy, and it is determined that the ultrasonic wave is received when the ultrasonic wave after several rounds of wavelength whose amplitude has increased to some extent is zero-crossed (shown by black dots in FIG. 5) Do.

  Therefore, in the ultrasonic flowmeter 150, the propagation times t1 and t2 from transmission to reception of the ultrasonic wave are longer by the delay arrival time equivalent to about two wavelengths than the original arrival time. . That is, in the propagation times t1 and t2, an error corresponding to the delay arrival time occurs.

  Here, the gas flow rate is usually derived based on the difference between the propagation time t1 and the propagation time t2. Therefore, even if the propagation times t1 and t2 both have an error corresponding to the delay arrival time with respect to the original arrival time, the delay arrival time is canceled by taking the difference between the propagation time t1 and the propagation time t2. The influence of this error is reduced when deriving the flow rate.

  On the other hand, since the sound velocity deriving unit 160 derives the sound velocity based on the propagation times t1 and t2 measured by the ultrasonic flow meter 150, if there is an error for the delay arrival time in the propagation times t1 and t2, the sound velocity is indicated. It is affected by this error when deriving.

  Therefore, the sound velocity deriving unit 160 subtracts the delay arrival time which is an error from the propagation times t1 and t2 measured by the ultrasonic flow meter 150, and derives arrival times ta1 and ta2 corresponding to the original arrival times.

なお、Ｌは一対の超音波送受信器１５０ａ、１５０ｂ間の距離を示し、Ｖはガスの流速を示す。 And arrival time ta1, ta2 corresponded to original arrival time can be expressed like a formula (1).

In addition, L shows the distance between a pair of ultrasonic transmitter-receivers 150a and 150b, V shows the flow velocity of gas.

Therefore, the sound velocity deriving unit 160 derives the sound velocity C based on the arrival times ta1 and ta2 corresponding to the original arrival time, using the following equation (2) in which the above equation (1) is simultaneously established.

  As described above, the sound velocity deriving unit 160 subtracts the delay arrival time of the ultrasonic wave that can not be detected with a small amplitude from the propagation times t1 and t2 measured by the ultrasonic flow meter 150, and corresponds to the original arrival time. The velocity of sound C can be accurately derived by deriving the velocity of sound C based on the arrival times ta1 and ta2 using the above equation (2). The delay arrival time may be measured in advance for each one of the sound velocity deriving units 160 by experiment, and the sound velocity deriving unit 160 of the same design measures one standard delay arrival time and one You may omit the measurement of a stand.

そして、流量導出部１６２は、導出したガスの流速Ｖに、ガス流路の断面積を乗算することにより、ガスの流量を導出する。 (Flow rate derivation unit 162)
The flow rate deriving unit 162 derives the flow velocity V of the gas based on the propagation times t1 and t2 measured by the ultrasonic flowmeter 150 using the following equation (3).

Then, the flow rate deriving unit 162 derives the flow rate of the gas by multiplying the flow rate V of the derived gas by the cross-sectional area of the gas flow path.

(Gas production plant 114)
FIG. 6 is a functional block diagram showing a schematic configuration of the gas production plant 114. As shown in FIG. As shown in FIG. 6, the gas production plant 114 includes a gas production unit 170, a gas chromatography 172, a communication circuit 174, a plant storage unit 176, and a plant control unit 178.

  The gas generation unit 170 generates a hydrocarbon-based gas by vaporizing the LNG, and supplies the gas to the gas supply pipe 132 (gas supply conduit network 130). The gas chromatography 172 analyzes the components of the gas generated by the gas generator 170 and supplied to the gas supply conduit network 130. The communication circuit 174 establishes wired communication with the center device 116. The factory storage unit 176 includes a ROM, a RAM, a flash memory, an HDD, and the like, and stores programs and various data used in the gas production factory 114.

  The factory control unit 178 includes a CPU and a DSP, and controls the entire gas generating factory 114 based on a program stored in the factory storage unit 176. The factory control unit 178 also functions as a gas characteristic identification unit 180 and a factory communication unit 182.

  The gas-characteristic specifying unit 180 specifies the relationship among the temperature, the sound velocity, and the unit calorific value of the gas generated by the gas generator 170 based on the component of the gas analyzed by the gas chromatography 172 as the gas characteristic. Specifically, the ratio of the hydrocarbon-based gas to the total of the components of the gas analyzed by the gas chromatography 172, the unit for the temperature and the speed of sound of the hydrocarbon-based gas of the components of the analyzed gas The gas characteristics are derived from the relationship of calorific value. The relationship (gas characteristics) of the unit calorific value to the temperature of the hydrocarbon-based gas and the velocity of sound is stored in advance in the factory storage unit 176. In addition, the gas production plant 114 is provided with a sound velocity deriving unit for deriving the sound velocity, and the relationship (gas characteristics) of the unit calorific value to the sound velocity of the hydrocarbon-based gas is derived based on the derived sound velocity. Good.

  Therefore, the gas characteristic specifying unit 180 is stored in the factory storage unit 176 when the mixed gas such as nitrogen, oxygen, and steam does not enter the hydrocarbon-based gas generated by the gas generation unit 170. The gas characteristics of hydrocarbon gas are read out as they are. On the other hand, when the miscellaneous gas is invading the hydrocarbon-based gas generated by the gas generation unit 170, the gas-characteristic specifying unit 180 stores the hydrocarbon-based gas stored in the factory storage unit 176. For the characteristics, the gas characteristics in which the proportion of hydrocarbon-based gas is considered will be derived.

  The factory communication unit 182 exchanges information with the center apparatus 116 through the communication circuit 174, and transmits information on the gas characteristic specified by the gas characteristic specifying unit 180 to the center apparatus 116 as needed.

  As described above, each gas production plant 114 transmits information on the gas characteristics of the gas delivered to the gas supply conduit network 130 to the center apparatus 116 as needed based on the analysis result of the generated gas component.

(Center device 116)
FIG. 7 is a functional block diagram showing a schematic configuration of the center device 116. As shown in FIG. As shown in FIG. 7, the center device 116 includes a communication circuit 190, a usage amount storage unit 192, a device storage unit 194, a gas characteristic storage unit 196, and a center control unit 198.

  The communication circuit 190 establishes wireless communication with the gateway device 112 via the base station 118 and establishes wired communication with the gas production plant 114. The usage amount storage unit 192 includes a ROM, a RAM, a flash memory, an HDD, and the like, and stores the velocity of sound and the flow rate of the gas received from each gas meter 110 in association with the gas meter 110. Therefore, the usage amount storage unit 192 holds the transition of the sound velocity and flow rate of the past gas for each gas meter 110. The device storage unit 194 includes a ROM, a RAM, a flash memory, an HDD, etc. like the usage storage unit 192, and stores the device 122 used via the gas meter 110 such as a pilot device in association with the gas meter 110. . The gas characteristic storage unit 196 is composed of a ROM, a RAM, a flash memory, an HDD, etc., similarly to the usage amount storage unit 192, associates the gas characteristic received from the gas production plant 114 with the gas production plant 114, and accumulates it. Therefore, the gas characteristic storage unit 196 holds the transition of the past gas characteristic for each gas production plant 114.

  The center control unit 198 is configured of a CPU and a DSP, and is stored in the usage storage unit 192, the device storage unit 194, and the gas characteristic storage unit 196 when executing the water supply position specifying process (the water supply position specifying method). The entire center device 116 is controlled based on the information. Further, the center control unit 198 functions as a center communication unit (gas information acquisition unit) 200, a factory identification unit 202, a calorific value derivation unit 204, a passing calorific value derivation unit 206, a water supply position identification unit 208, and an abnormality diagnosis unit 210. Do.

  The center communication unit 200 exchanges information with each gas meter 110 through the communication circuit 190, for example, receives and acquires the sound velocity and the flow rate of the gas from the gas meter 110. In addition, the center communication unit 200 exchanges information with each gas producing plant 114 through the communication circuit 190, and receives gas characteristics from the gas producing plant 114, for example.

  The plant specifying unit 202 is a generation source of the gas supplied to the gas meter 110 based on the sound velocity itself of the gas received from the gas meter 110 or its time-series change and the gas characteristic received from the gas generation plant 114, that is, Among the plurality of gas producing plants 114, the gas producing plant 114 which has produced the supplied gas is specified.

  FIG. 8 is a diagram for explaining time-series changes in the sound velocity of gas. FIG. 8 (a) is a diagram for explaining the change in the velocity of sound when the gas supplied to the gas meter 110 is changed when the temperature of the gas is constant, and FIG. 8 (b) is the temperature of the gas Is a diagram for explaining the change in the speed of sound when the gas supplied to the gas meter 110 is changed when the value of x is not constant.

  As shown in FIG. 8A, at the time when the temperature of the gas is constant and the gas supplied to the gas meter 110 is not changed (before time t11 and after time t11), the speed of sound is also It is constant. Then, when the gas supplied at time t11 is changed, that is, when the gas supply source (gas production plant 114) is changed, the sound velocity of the gas is also changed.

  Also, as shown in FIG. 8B, in the time when the temperature of the gas is not constant and the gas supplied to the gas meter 110 is not changed (before time t12 and after time t12), The sound velocity of the gas also changes according to the temperature of the gas. Then, when the gas supplied at time t12 is changed, that is, when the gas supply source (gas production plant 114) is changed, the velocity of sound of the gas is more abrupt than in the case where it is changed according to the temperature of the gas. Change (in steps).

  That is, as shown in FIGS. 8A and 8B, regardless of whether the temperature of the gas is constant or not, when the supplied gas is changed, the velocity of sound of the gas also changes rapidly.

  Therefore, the factory identification unit 202 derives the time-series change of the sound velocity of the gas received from the gas meter 110, more specifically, the derivative value of the sound velocity of the gas, and the derived derivative value is the source of the gas supply source. If the predetermined threshold that is considered to be changed is exceeded, it is determined that the supplied gas has been changed.

  Here, the plant specifying unit 202 monitors which gas meter 110 the gas generated at the gas generating plant 114 is supplied to the gas supply conduit network 130 in a time series manner, thereby generating which gas meter 110 generates which gas. A gas supply map is generated which indicates whether the gas generated at the factory 114 is being supplied. Then, when the plant specifying unit 202 determines that the gas supplied to the gas meter 110 of 1 is changed, the gas generated at any of the gas generating plants 114 is referred to by referring to the gas supply map. Identify what is being supplied to 110.

  FIG. 9 is a diagram for explaining a gas supply map. Here, as described above, the plurality of gas meters 110 are disposed in the gas supply conduit network 130, and the gas is supplied to each of the gas meters 110 in a state where the gases generated in the plurality of gas production plants 114 are mixed. Be done.

  For example, as illustrated in FIG. 9A, in the gas supply conduit network 130, it is assumed that the gas generated at each gas generation plant 114 is supplied to the gas meter 110 (demand point) with the boundary 134 as the boundary. Do. Then, as shown in FIG. 9B, in the gas supply conduit network 130, when the supply range of the gas generated in each gas generating plant 114 changes with the passage of time, the boundary 134 also changes. Become. Then, when the sound velocity of the gas derived in the gas meter 110 changes rapidly, the plant specifying unit 202 updates the gas supply map by specifying the change in the boundary 134 from the sound velocities of the gas in the plurality of gas meters 110. Do.

  Thus, the factory identification unit 202 monitors the sound velocity of the gas derived by the plurality of gas meters 110 in time series, and determines the timing of the rapid change of the sound velocity of the gas derived by the plurality of gas meters 110 Then, it is determined to which gas meter 110 the gas generated at which gas production plant 114 is supplied, and the gas supply map is updated. In other words, it can be said that the gas supply map indicates to which range the gas generated at each gas production plant 114 is supplied in the gas supply network 130.

  When the gas production plant 114 that has generated the gas supplied to the gas meter 110 is identified, the calorific value derivation unit 204 is based on the identified gas properties of the gas production plant 114 and the speed of sound received from the gas meter 110. , To derive the unit calorific value of the gas.

  FIG. 10 is a diagram showing the relationship between the temperature, the speed of sound, and the type of gas (the calorific value in the standard state). FIG. 11 is a diagram showing the relationship between the speed of sound and the unit heating value. Below, the calorific value in a standard state is also called standard calorific value.

  Here, as shown in FIG. 10, regardless of the type (standard calorific value) of hydrocarbon-based gas, if the temperature of the gas is low, the speed of sound of the gas will be slowed, and as the temperature of the gas becomes higher, The speed of sound increases. On the other hand, when the type of gas (standard calorific value) is different, the sound velocity of the gas is different even if the temperature of the gas is the same, and the temperature of the gas is different even if the sound velocity of the gas is the same. More specifically, as the standard calorific value of gas increases, the sound velocity of the gas decreases even if the temperature of the gas is the same, and the temperature of the gas increases even if the sound velocity of the gas is the same .

If the temperature and sound velocity of the gas can be specified by such characteristics, it is possible to estimate the type of gas (standard calorific value). For example, when the temperature of the gas is 20 ° C. and the sound velocity of the gas is 415 m / s, the type of gas (standard calorific value) can be estimated to be 44.4 MJ / Nm ³ .

  By the way, based on the relationship between the temperature, the speed of sound and the type of gas (standard calorific value) shown in FIG. 10, the temperature and the temperature for different types of gas (standard calorific value) when the speed of sound is made equal to 405 m / s. The unit calorific value is shown in Table 1.

As apparent from Table 1, when the sound velocity is made equal to 405 m / s, the unit calorific value is about 43.5 ± 0.5 MJ / m regardless of the type of gas (standard calorific value) and temperature. It becomes a fixed value that fits in ³ .

  Further, as shown in FIG. 11, regardless of the type of gas (standard calorific value), the speed of sound and the unit calorific value can be represented by the relation of substantially the same line. Therefore, it can be understood that the unit calorific value can be derived based only on the speed of sound regardless of the type of gas (standard calorific value). In Table 1 and FIG. 11, although there is a slight error in the relationship between the speed of sound and the unit heat generation amount depending on the type of gas (standard heat generation amount), the error is about ± 2.5% or less The unit calorific value can be accurately derived using only the velocity of sound, regardless of the type of gas.

  In the following, it will be theoretically described that it is possible to derive the unit heating value with only the sound velocity C.

ここで、γは混合気体の比熱比を示し、Ｒは気体定数（Ｊ／ｍｏｌ／Ｋ）を示し、Ｍは混合気体の平均分子量（ｋｇ／ｍｏｌ）を示す。 The sound velocity C can be expressed by the following equation (4).

Here, γ indicates the specific heat ratio of the mixed gas, R indicates the gas constant (J / mol / K), and M indicates the average molecular weight (kg / mol) of the mixed gas.

ここで、ＣＶ_０は標準発熱量（ｋＪ／Ｎｍ^３）を示し、ａ、ｂは定数（飽和炭化水素の理想気体の場合、ａ＝２．１×１０^６、ｂ＝７．４×１０^３、飽和炭化水素の実在気体の場合、ａ＝２．４×１０^６、ｂ＝５．７×１０^２）を示す。 Further, the relationship between the gas density (average molecular weight) and the standard calorific value can be represented by the following formula (5).

Here, CV ₀ indicates a standard calorific value (kJ / Nm ³ ), and a and b indicate constants (in the case of an ideal gas of saturated hydrocarbon, a = 2.1 × 10 ⁶ , b = 7.4 × 10 ³ In the case of a saturated hydrocarbon real gas, a = 2.4 × 10 ⁶ , b = 5.7 × 10 ² ).

ここで、ＣＶ_Ｔは温度Ｔにおける単位発熱量（ｋＪ／ｍ^３）を示し、ｐは温度Ｔにおける圧力（供給圧力、Ｐａ）を示し、ｐ_０は標準圧力（１０１３２５Ｐａ）を示し、Ｔ_０は標準温度（２７３．１５Ｋ）を示す。 Moreover, the unit calorific value of the gas in the temperature T can be represented by following formula (6).

Here, CV _T represents a unit calorific value (kJ / m ³ ) at temperature T, p represents a pressure (supply pressure, Pa) at temperature T, p ₀ represents a standard pressure (101325 Pa), and T ₀ is The standard temperature (273.15 K) is shown.

ここで、Ｍは都市ガスであれば１６〜２０程度であり、ａ>>ｂ／Ｍの関係が成り立つため、式（７）は式（８）と表すことができる。

The following equation (7) can be derived from these equations (4) to (6).

Here, if M is city gas, it is about 16 to 20, and the relationship of a >> b / M holds, so equation (7) can be expressed as equation (8).

  As described above, since the equation (8) is not affected by the temperature T at the time of measurement, if the supply pressure p is known, the unit calorific value is derived only from the speed of sound C without measuring the temperature T. It is understood that is possible. In the case where the unit calorific value is derived only from the speed of sound C without measuring the temperature T, the accuracy of the derivation is slightly high if it is a straight chain saturated hydrocarbon gas. Further, it is known that the speed of sound is hardly influenced by the pressure, so that the pressure p may be corrected according to the normal Boyle's law by measuring the pressure, if necessary.

  The passing heat generation amount deriving unit 206 integrates the product of the unit heating value of the gas derived by the heat generation amount deriving unit 204 and the flow rate received from the gas meter 110 with respect to the time axis, whereby the heat generation of the gas is generated. Derive the quantity.

  By the way, when the feed water enters the gas supply pipe 132, the gas feed pipe 132 may be blocked by the feed water, which may cause trouble in the supply of the gas to the gas supply location (the gas meter 110). Therefore, it is necessary to specify the position of the feed water before the gas supply pipe 132 is blocked by the feed water.

  On the other hand, since the gas generated in the gas generating plant 114 is in a dry state, when the feed water is intruding into the gas supply pipe 132, the position (location) where the feed water is infiltrating in the gas supply pipe 132 When the gas produced at the gas producing plant 114 passes through, the feed water is vaporized to become steam. Therefore, in such a case, the vaporized steam as well as the gas produced at the gas production plant 114 will be mixed and flow downstream. At this time, when the gas passes through the feed water section of several meters, the amount of water vapor in the gas rises to the saturated water vapor pressure. When the gas passing through the position where the feed water is inflow is, for example, 10 ° C., about 1% by volume of water vapor is mixed with the gas generated in the gas production plant 114. In addition, when the gas passing through the position where the feed water has infiltrated is, for example, 20 ° C., the gas generated in the gas generating plant 114 is mixed with water vapor of about 2% by volume ratio.

FIG. 12 is a view showing the relationship between the temperature and the speed of sound in the case of only a hydrocarbon-based gas and in the case where water vapor is mixed with the hydrocarbon-based gas. Here, as shown in FIG. 12, and if the standard calorific value 44.0 only hydrocarbon-based gas (MJ / Nm ^3), the standard calorific value of 44.0 (MJ / Nm ³⁾ hydrocarbon The relationship between the temperature and the speed of sound is represented on a different line in the case where 1% water vapor (water) is mixed with the system gas. Specifically, even at the same temperature, the speed of sound is faster in the case where 1% of steam is mixed with the hydrocarbon-based gas than in the case where only the hydrocarbon-based gas is mixed.

  Further, the unit calorific value also differs between the case of hydrocarbon-based gas alone and the case of 1% water vapor (water) entering the hydrocarbon-based gas. For example, the unit calorific value is about 0.6% lower in the case where 1% of water vapor infiltrates into the hydrocarbon-based gas than in the case where only the hydrocarbon-based gas is introduced.

  FIG. 13 is a diagram for explaining the velocity of sound at the gas meter 110 when the feed water is mixed in the gas supply pipe 132. As described above, when feed water enters the gas supply pipe 132, the sound velocity of the downstream gas becomes higher than that of the portion of the gas supply pipe 132 where the feed water is introduced. For example, as shown in FIG. 13, when the temperature is constant in the gas supply pipe 132 and the feed water 136 intrudes in the gas supply pipe 132, the position is more than the position where the feed water 136 intrudes in the gas supply pipe 132. In the gas meter 110 connected upstream, it is assumed that the sound velocity of the gas is derived as 415 m / s. In such a case, the hydrocarbon-based gas is mixed with steam on the downstream side of the feed water 136 in the gas supply pipe 132, and is connected downstream of the position where the feed water 136 infiltrates in the gas supply pipe 132. In the gas meter 110, the sound velocity of the gas is derived as, for example, 418 m / s.

  Therefore, the water supply position specifying unit 208 monitors the speed of sound of the gas derived by the plurality of gas meters 110 connected from the upstream to the downstream in the gas supply pipe 132 as calorific value information (gas information) related to the calorific value (illustrated) When the sound speed is high from a certain position to the downstream, it is determined that the feed water is intruding at the position (most upstream side) where the sound speed is high. That is, the water supply position specifying unit 208 specifies the position (most upstream side) at which the sound velocity is high as the position of the supply water based on the difference (difference) in the sound velocity of the gas from the upstream to the downstream in the gas supply pipe 132 .

  However, the sound velocity derived by the gas meter 110 also changes depending on the temperature of the supplied gas, as shown in FIG. 10, for example. However, when steam is mixed with the gas generated at the gas production plant 114, the speed of sound is always higher than when the steam generated at the gas production plant 114 is not mixed. Therefore, if the water supply position specifying unit 208 constantly monitors the sound velocity received from the gas meter 110 in time series, compared to the change in the sound velocity around the gas supply pipe 132, the feed water has infiltrated. It is possible to determine that the feed water is infiltrating at that position by determining the change in the speed of sound due to. For example, although the speed of sound around the gas supply pipe 132 is lowered as the air temperature is lowered, if the speed of sound is high in a certain area, the feed water infiltrates the area. It is determined that there is.

  Also, by storing the sound speed in association with the past weather and time (geographical information), the water supply position specifying unit 208 redundantly uses the past weather and time similar to the current weather and time. It may be determined that the feed water has infiltrated when the current speed of sound is always higher by a certain value than the speed of sound in the past as compared with the speed of sound associated. Thereby, the detection accuracy of the feed water can be improved.

  The abnormality diagnosis unit 210 diagnoses based on the transition of the past passing heat generation amount stored in the usage amount storage unit 192 whether or not the current passing heat generation amount is abnormal. The abnormality diagnosis unit 210 can also diagnose an abnormality based on the rated passage heating value of the gas in the device 122 stored in the device storage unit 194.

  As described above, the center device 116 according to the present embodiment is configured in the gas supply pipe 132 based on the difference in the velocity of sound derived by the plurality of gas meters 110 connected from the upstream to the downstream of the gas in the gas supply pipe 132. Identify the location of the feed water. Thus, when the feed water enters the gas supply pipe 132, the position of the feed water can be specified. That is, before the feed water enters the gas supply pipe 132 and the gas supply pipe 132 is closed, the position of the feed water can be identified early.

<Modification>
FIG. 14 is a functional block diagram showing a schematic configuration of a gas meter 300 according to a modification. As shown in FIG. 14, the gas meter 300 differs from the above-described gas meter 110 in that a temperature sensor 302 is provided, and the other configuration is the same as that of the gas meter 110.

  The temperature sensor 302 measures the temperature of the supplied gas. Then, the meter communication unit 166 transmits the sound speed derived by the sound velocity deriving unit 160, the temperature measured by the temperature sensor 302, and the flow rate derived by the flow rate deriving unit 162 to the center apparatus 116 every hour.

In the center device 116, the calorific value deriving unit 204 derives the unit calorific value (MJ / m ³ ) of the gas based on the speed of sound and the temperature received from the gas meter 300.

  Further, the water supply position specifying unit 208 specifies the water supply position based on the unit calorific value of the gas derived by the calorific value deriving unit 204. As described above, when steam is mixed with the gas generated at the gas production plant 114, the unit calorific value decreases, so the feed water position specifying unit 208 connects the gas supply pipe 132 from the upstream to the downstream. By monitoring the unit calorific value with the gas meter 300, if the unit calorific value is low from a certain position to the downstream, the feed water enters the position where the unit calorific value is low (most upstream) I judge that it is.

  As described above, in the gas meter system having the gas meter 300, the gas meter 300 measures and derives the temperature and the speed of sound of the gas, and the center device 116 supplies the gas meter 300 with the gas supplied based on the temperature and the speed of sound. The position of the feed water can be specified by deriving and monitoring the unit calorific value.

  Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the appended claims, and of course these also fall within the technical scope of the present invention. It is understood.

  In the above embodiment, although the calorific value deriving unit 204 derives the unit calorific value based on the sound velocity, when the position of the feed water is specified, the downstream side is more than the position of the feed water. The unit calorific value which carried out subtraction correction of the calorific value of the water vapor which has entered may be derived to gas meter 110 connected to this. This makes it possible to charge more appropriately.

  In the above embodiment, the center device 116 derives the unit heating value based on the speed of sound derived by the gas meter 110 and the gas characteristic derived at the gas production plant 114. However, the present invention is not limited to this, and the unit calorific value may be derived using the above equation (8) based on the derived sound speed. In addition, the gas meter 110 may derive the passing calorific value.

  Further, in the above embodiment, the sound velocity is adapted as calorific value information (gas information) regarding the calorific value of the gas supplied to the gas meter 110, but a unit calorific value may be adapted. Further, when the unit calorific value is applied as calorific value information (gas information), referring to the gas supply map, the unit calorific value is generated in the range where the gas generated at the same gas generating plant 114 is supplied. It may be specified that the feed water is infiltrating in the region where the amount is low.

  In the above embodiment, the gas chromatography 172 analyzes the components of the gas generated by the gas generator 170 and supplied to the gas supply conduit network 130, but the gas supply conduit network 130 supplies Analyzers other than gas chromatography may be adapted, as long as they can analyze the components of the gas.

  In the above embodiment, the position of the feed water is specified based on the calorific value information (gas information) on the calorific value of the hydrocarbon gas, but hydrogen gas, oxygen gas, nitrogen gas, etc. Based on gas information (for example, sound velocity), the position of the feed water can also be specified using the difference between the gas information and the gas information in a mixed state of water vapor.

  The present invention relates to a center device for specifying the position of feed water that has entered the gas supply pipe for supplying gas, and a method for specifying the position of the feed water.

Reference Signs List 100 gas meter system 110 gas meter 114 gas generation factory 116 center device 150 ultrasonic flow meter 160 sound velocity deriving unit 162 flow rate deriving unit 170 gas generating unit 180 gas characteristic specifying unit 200 center communication unit (gas information acquiring unit)
202 Factory identification unit 204 Heat generation amount derivation unit 206 Passage heat generation amount derivation unit 208 Water supply position identification unit

Claims (4)

A gas information acquisition unit for acquiring the sound velocity of the gas supplied to each of the plurality of gas meters from each of the plurality of gas meters;
Based on the sound velocity difference of the gas gas meter from the upstream of the gas in the gas supply pipe plurality of connected to a downstream for supplying the gas to the plurality of gas meters, the position of the pointing water in the gas supply pipe A center device characterized by comprising a water supply position specifying unit for specifying.   The center apparatus according to claim 1, wherein the gas comprises a hydrocarbon-based gas. A calorific value deriving unit that derives the calorific value of the gas used in the gas meter based on the sound velocity of the gas;
The heat generation amount deriving unit
With respect to the gas meter connected downstream of the position of the feed water specified by the water supply position specifying unit, a heat generation amount obtained by subtracting and correcting the heat generation amount of the entering water vapor is derived. The center apparatus according to claim 1 or 2. The velocity of sound of the gas supplied to each of the plurality of gas meters is obtained from each of the plurality of gas meters,
The position of the feed water in the gas supply pipe is determined based on the difference in the velocity of sound of the gas of the gas meters connected upstream and downstream of the gas in the gas supply pipe for supplying the gas to the plurality of gas meters. Water supply location identification method to identify.

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