JP6264898B2 - Steam pipe loss measurement system and measurement method - Google Patents

Description

  The present invention relates to a steam pipe loss measuring system and measuring method.

  In factories in the industrial field, steam is used for a wide range of applications from heating in production processes to heating and humidification of air conditioning. Steam can cover a wide temperature range from a low temperature range of about 45 ° C. to a high temperature range of about 170 ° C., so to speak, it is an easy-to-use heat medium. For this reason, steam pipes are generally laid in many places in the factory, and steam is generally sent to each production process from a centrally installed boiler.

  FIG. 6 shows a general conceptual diagram of a steam system laid in a factory. Steam produced by a steam production device such as a boiler is sent to a steam header and used for heating in a production process or heating / humidification of an air conditioner. Steam used for various purposes is collected as drain, collected in a return water tank, etc., and then supplied again to the boiler. Further, a plurality of steam traps for discharging drains generated by condensation of steam accompanying heat radiation from the piping are arranged in the middle of the piping.

  In the steam system shown in FIG. 6, the following four losses can be considered with respect to the input fuel energy. (1) Loss of boiler: Loss that becomes apparent by calculating the amount of heat produced by the boiler with respect to the boiler fuel flow (so-called loss associated with boiler efficiency), (2) Loss during air supply (piping): Loss discharged from the steam trap on the pipe due to heat radiation from the pipe, or loss due to leaked steam from the damaged part of the valve or pipe, (3) Trap loss after the load equipment: From the steam trap to collect the drain (4) Loss of recovery: loss from piping to return drain. Temperature drops due to water replenished to prevent pump cavitation when the return water tank is open to the atmosphere, for example. Loss by doing. The energy obtained by subtracting these losses (1) to (4) from the fuel supplied to the boiler is the energy that is effectively utilized in the production process and air conditioning equipment.

  Loss at the time of air supply (piping) (hereinafter referred to as “piping loss”) includes the following three types of loss. (1) The drain loss is a loss in which the steam in the pipe is condensed and drained along with heat radiation from the pipe and is discharged from the steam trap. (2) The trap leak is a loss in which the steam in the pipe leaks simultaneously when the drain trapped by the sweep trap is discharged. (3) Leakage such as piping is a loss in which steam leaks due to physical damage or the like in a piping system including steam piping, valves, flanges, and the like.

  The pipe loss measurement method is as follows. That is, a steam flow meter is installed on each of the pipe inlet side (immediately after the boiler outlet) and the pipe outlet side (immediately before various load facilities), and the loss is calculated based on the comparison of the measurement results. However, in this method, since it becomes possible to measure by directly installing the steam flow meter on the pipe, if the pipe outlet side has a complicated configuration, it is necessary to install a plurality of flow meters. Moreover, it is necessary to cut the existing steam pipes for new installation. In addition, the wetness may not be fully evaluated because not all the moisture (drain) is removed from the steam trap.

As another method for measuring the pipe loss, there is a method using a special device such as a thermography. However, this method is expensive, requires specialized technology for analysis and evaluation of measurement results, and tends to be insufficient in pipe surface temperature measurement accuracy. Evaluation of thermal conductivity of steam pipes or insulation materials. Has problems such as being relatively difficult.
On the other hand, there is provided a method of measuring a steam pipe loss by measuring the amount of evaporation in the steam pipe in this state in an unloaded state in which the internal space of the steam pipe is substantially closed space (for example, Patent Document 1).

Japanese Patent No. 4924762

  When there is no load, the flow velocity in the steam pipe becomes almost zero, but when a load facility such as a heat utilization device is actually operated (during normal operation), a flow speed is generated in the steam pipe. The flow velocity generated in the steam pipe has a considerable influence on the pipe loss. However, in the measurement method of the above prior art, the influence of the flow velocity generated in the steam pipe is not taken into consideration. Therefore, it has been desired to provide a new technique capable of measuring the pipe loss with high accuracy by taking into consideration the influence of the flow velocity in the steam pipe.

  An object of this invention is to provide the measuring system and measuring method which can measure the loss of a steam pipe, especially piping loss with high precision.

According to an aspect of the present invention, a system for measuring a loss of a steam pipe connected to a steam production apparatus and a load facility, the first apparatus creating a substantially closed space including at least a part of the steam pipe; A second device for controlling the amount of steam supplied from the steam producing device into the steam tube so as to keep the pressure in the steam tube substantially constant, and a value relating to the amount of evaporation in the substantially closed space. Using the measurement result of the third device, the fourth device for measuring the loss of the steam pipe using the measurement result of the third device, and the information on the heat dissipation corresponding to the flow state of the steam in the steam pipe A fifth device that corrects the measurement value of the loss, and the fifth device is a correction obtained from the in-tube heat transfer coefficient corresponding to the liquid film thickness that adheres to the steam pipe that varies depending on the flow velocity of the steam. The measured value of the loss using the coefficient That correct.

According to another aspect of the present invention, there is provided a method for measuring a loss of a steam pipe connected to a steam production apparatus and a load facility. The loss measurement method includes a first step of creating a substantially closed space including at least a part of the steam pipe, and the steam production apparatus from the steam production apparatus so as to keep the pressure in the steam pipe substantially constant. The second step of controlling the amount of steam supplied into the pipe, the third step of measuring the value related to the amount of evaporation in the substantially closed space, and the measurement result of the value related to the amount of steam supplied, A fourth step of measuring the loss of the pipe, and a fifth step of correcting the measured value of the loss using information related to heat dissipation corresponding to the flow state of the steam in the steam pipe. In the fifth step, , we correct the measured value of the loss by using a correction coefficient obtained from the tube heat transfer coefficient which corresponds to the liquid film thickness to adhere to the steam pipe that varies with the flow rate of the steam.

  According to the measurement system and the measurement method, it is possible to preferably measure the pipe loss by using the measurement result of the value related to the steam supply amount to the substantially closed space.

It is the schematic which shows a loss measurement system. It is a schematic diagram which shows a control unit. It is a graph regarding the average liquid film thickness of a downward annular flow. It is a graph regarding the dimensionless heat transfer coefficient by general velocity distribution. It is the schematic which shows the modification of a loss measurement system. It is a conceptual diagram which shows a general steam system.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing a loss measurement system 1. In FIG. 1, the steam pipe 10 is disposed between a steam production apparatus 20 (such as a boiler) and a load facility 30. Steam from the steam production apparatus 20 flows through the steam pipe 10 and is sent to the load facility 30. In the load facility 30, steam or steam heat is used. The steam discharged from the load facility 30 is collected as a drain, collected in the return water tank 25, and then supplied again to the steam production apparatus 20. The steam pipe 10 is heat-retained by heat retention means (not shown). Various known heat retaining means can be applied. The heat retaining means includes, for example, a heat retaining material that covers the outer surface of the steam pipe 10.

  The steam pipe 10 is provided with a plurality of steam traps ST1, ST2, and ST3 that discharge drains generated by condensation of steam accompanying heat dissipation in the pipes. In FIG. 1, the number of steam traps STn is three. The number of steam traps STn varies depending on equipment specifications. At least a part of the drain generated by condensation in the steam pipe 10 is captured by the steam traps ST1, ST2, and ST3. Various known steam traps are applicable. Normally, the steam traps ST1, ST2 and ST3 have a structure capable of appropriately discharging the captured drain.

  Between the steam production apparatus 20 and the steam trap ST1 in the steam pipe 10, a flow sensor 42 and a pressure sensor (third apparatus) 44 are disposed. At least the measurement result of the pressure sensor 44 is sent to the control unit (second device) 40. In the steam supply system including the steam production apparatus 20, the supply of steam can be controlled based on the measurement result of the pressure sensor 44 so that the internal pressure of the steam pipe 10 is constant.

  A valve (first device) 27 is disposed near the inlet of the load facility 30 in the steam pipe 10 (between the final steam trap ST3 and the load facility 30). By opening the valve 27, steam from the steam production apparatus 20 can be input to the load facility 30. By closing the valve 27, the steam input from the steam production apparatus 20 to the load facility 30 is shut off.

  A flow rate sensor 46 that measures the amount of water supplied to the steam producing apparatus 20 is disposed near the return water tank 25. The measurement result of the flow sensor 46 is sent to the control unit 40. The control unit (fourth device) 40 can measure the piping loss in the steam pipe 10 based on the measurement result of the flow sensor 46. Moreover, in this embodiment, the control unit (5th apparatus) 40 can correct | amend the measured value of piping loss using the information regarding the thermal radiation corresponding to the flow state of the steam in a steam pipe so that it may mention later. The loss measurement system 1 can include a valve 27, a flow sensor 42, a pressure sensor 44, a flow sensor 46, and a control unit 40.

  FIG. 2 is a schematic diagram showing the control unit 40. In FIG. 2, the computing device 50 is, for example, a computer system. The control unit 40 includes an input device 127 and a display device (output device) 128 in addition to the calculation device 50. The computing device 50 includes a converter 123 such as an A / D converter, a CPU (arithmetic processing means) 124, a memory 125, and the like. Measurement data sent from a sensor (such as the flow sensor 46) of the loss measurement system 1 is converted by the converter 123 or the like as necessary, and is taken into the CPU 124. In addition, initial setting values, temporary data, and the like are taken into the computing device 50 via the input device 127 and the like. The display device 128 can display information regarding input data, information regarding calculation, and the like.

  Based on the measurement data and the information stored in the memory 125, the CPU 124 can execute a calculation related to the loss of the steam pipe. For example, the heat loss (pipe loss) of the steam pipe 10 can be calculated using the measurement result of the flow sensor 46, and the calculated pipe loss can be corrected as described later. Hereinafter, an example of a calculation method related to the loss of the steam pipe 10 will be described.

  This measurement method focuses on the amount of water supplied to the steam production apparatus 20 such as a boiler that produces steam. The steam produced by the steam production apparatus 20 is collected after working at various loads while generating a loss. In this measurement method, steam is prevented from flowing into the load facility 30 such as (1) stopping the load facility 30 or (2) closing the valve 27 immediately before the load facility 30. That is, a substantially closed space mainly including the internal space of the steam pipe 10 is created. Hereinafter, this state is appropriately referred to as “no load”. The steam production apparatus 20 supplies steam so as to keep the pressure in the steam pipe 10 constant. This is to supply steam that has been evaporated from the steam pipe 10 and escaped from the steam pipe 10, that is, steam drainage due to heat radiation. Drain is appropriately discharged from the steam traps ST1, ST2, and ST3. If the steam production apparatus 20 is operated in the same manner as in normal times, the amount of water supplied becomes a loss in the piping.

  In the measurement, the amount of water supplied to the steam production apparatus 20 is measured as a value related to the amount of evaporation in a substantially closed space, and the steam pipe is based on the obtained water supply amount and the produced steam properties and the like based on the formula (1). Calculate the loss.

_{Q = F w × (h s} -C 0 T c) / S ... (1)

here,
Q: Steam pipe loss (kW)
F _w : Amount of water supply (measured value) (kg)
h _s : saturated steam enthalpy of production steam (kJ / kg)
T _c : Outside air temperature during measurement (environmental temperature) (° C)
S: Measurement time (s)
C ₀ : Specific heat of water (kJ / kg · ° C)

Here, when there is no load (when the steam supply to the load equipment is zero), the amount of steam supplied from the boiler to keep the steam piping pressure constant is the amount of drain condensed by heat dissipation in the steam piping, or from piping / valves. The amount of leaked steam is basically equal. In other words, it is considered that the amount of heat lost in the steam pipe can be grasped by measuring the amount of steam generated by the boiler when there is no load.
However, it is assumed that the heat transfer coefficient in the pipe is greatly different between no load and normal operation.

  Therefore, the degree of influence on the overall heat transfer coefficient is examined using the heat transfer coefficient in the pipe during no load and normal operation.

  The following formula (2) shows the basic formula for heat dissipation.

here,
q: Amount of heat dissipated per unit pipe length (W / m),
T ₀ : Pipe internal temperature (pipe steam temperature) (° C),
T ₁ : outside air temperature (atmospheric temperature) (° C.)
α ₁ : In-pipe heat transfer coefficient (W / m ² / ° C.),
α ₂ : heat transfer coefficient from the heat insulating material surface to the atmosphere (W / m ² / ° C.),
λ ₁ : thermal conductivity of heat insulation (W / m / ° C.)
r ₀ : Pipe inner diameter (m),
r ₁ : Piping outer diameter (m),
r ₂ : heat insulation outer diameter (outer diameter of heat insulating material) (m).

  When there is no load (no flow), the steam flow rate is low and can be regarded as almost zero. On the other hand, during normal operation, the steam flow rate is high and a flow rate is generated in the pipe. Moreover, in the steam pipe 10 at the time of normal operation, it becomes an annular flow in which drain condensed by heat radiation adheres to the pipe wall as a liquid film. The thickness of the liquid film adhering to the tube wall varies depending on the flow velocity in the steam tube 10.

Here, the flow state (annular flow) of the steam in the steam pipe 10 during normal operation will be described.
FIG. 3 is a graph relating to the average liquid film thickness of the downward annular flow. FIG. 4 is a graph relating to a dimensionless heat transfer coefficient based on a general velocity distribution. In FIG. 3, the horizontal axis indicates the Reynolds number, and the vertical axis indicates the thickness of the liquid film. In FIG. 4, the horizontal axis indicates the Reynolds number, the vertical axis indicates the heat transfer coefficient (W / m ² / ° C.) in the tube, the solid line indicates the tendency of the turbulent liquid film, and the dotted line indicates the laminar liquid film. It shows a trend. In the normal operation in the present embodiment, the case of the laminar liquid film in FIG. 4 is applied. 3 and 4, τ is a shearing force exerted on the surface of the liquid film attached to the tube wall by the vapor flow flowing through the vapor tube 10. The shear force τ is expressed by the following formula (3).

here,
c _f : coefficient of friction at the gas-liquid boundary,
γ _v : specific weight of steam,
g: acceleration of gravity,
u _v : steam flow rate,
u _l : liquid film flow rate.

  As shown in FIG. 3, it can be seen that the thickness of the liquid film increases in an OR linear manner almost in proportion to the Reynolds number (that is, the vapor flow velocity). This is a common tendency regardless of the magnitude of the shearing force τ. Moreover, as shown in FIG. 4, in the case of a laminar liquid film, it can be seen that the heat transfer coefficient in the tube decreases as the Reynolds number increases.

That is, during normal operation (in a state where there is a flow), the thickness of the liquid film increases as the Reynolds number increases (the increase in the flow rate of steam). Since the liquid film adhering to the tube wall becomes a thermal resistance, the thermal resistance increases as the thickness of the liquid film increases. As a result, the in-tube heat transfer coefficient defined by α ₁ in the above formula (2) is affected. That is, during normal operation (in a state where there is a flow), it is necessary to use the heat transfer coefficient in the tube in consideration of the heat dissipation characteristics that vary with the flow velocity.

  Therefore, in the evaluation method according to the present embodiment, the measurement result of the steam pipe loss Q at the time of no load (correction) is corrected by correcting the measurement result of the steam pipe loss Q at the time of no load shown by the above formula (1). The later measured value) can be used as it is as a result of pipe loss during normal operation.

  In the present embodiment, the correction coefficient used for the correction is defined based on information on heat dissipation corresponding to the flow state of the steam in the steam pipe 10. Specifically, as described later, it is defined by the ratio (qr / qm) of the theoretical heat dissipation amount qr during normal operation and the theoretical heat dissipation amount qm in the no-load state.

Hereinafter, a method for calculating the correction coefficient will be described.
First, the theoretical amount of heat release qr of the steam pipe 10 during normal operation (flowing state) is defined. In this case, the Reynolds number (steam flow velocity) is obtained by calculation as information relating to the flow state of the steam. The Reynolds number is obtained from, for example, the pipe diameter, the steam flow rate, the density, the viscosity, and the like.

Subsequently, the in-tube heat transfer coefficient is obtained using the Reynolds number obtained by calculation as described above and the graph shown in FIG. Here, in the graph shown in FIG. 4, the heat transfer coefficient in the tube varies depending on the shearing force. Therefore, the shear force τ is calculated based on the above equation (3) using values related to the vapor flow rate and the liquid film flow rate. Then, the tube heat transfer coefficient corresponding to the calculated shear strength τ determined from the graph shown in FIG. 4, the obtained tube heat transfer coefficient is replaced with alpha ₁ in the formula (2).

  Thereby, the theoretical heat radiation amount qr in the normal operation can be derived from the above equation (2).

  Next, the theoretical amount of heat release qm of the steam pipe 10 in a no-load state (state without flow) is defined. In this case, first, the Reynolds number (steam flow velocity) is obtained as information regarding the flow state of the steam in the steam pipe 10. In the no-load state, the liquid film thickness can be regarded as almost zero. From the graph shown in FIG. 3, the Reynolds number at which the liquid film becomes almost zero can be extrapolated.

Subsequently, the in-tube heat transfer coefficient is obtained using the Reynolds number extrapolated as described above and the graph shown in FIG. Here, in the graph shown in FIG. 4, the heat transfer coefficient in the tube varies depending on the shearing force. Since there is no flow in the pipe in the no-load state, the shearing force τ calculated from the difference between the vapor flow rate and the liquid film flow rate can be regarded as almost zero. Therefore, the heat transfer coefficient in the tube corresponding to the shearing force τ = 0 is obtained from the graph shown in FIG. 4, and the obtained heat transfer coefficient in the tube is replaced with α _{1 in the} above equation (2).

  Thereby, the theoretical heat radiation amount qm in the no-load state is derived from the above formula (2).

  In the present embodiment, the ratio (qr / qm) of the theoretical heat dissipation amount qr during normal operation and the theoretical heat dissipation amount qm in the no-load state, calculated as described above, is used as the correction coefficient.

  Subsequently, the control unit 4 multiplies the correction coefficient (qr / qm) to correct the steam pipe loss Q calculated by the above formula (1).

  Here, in the measurement of the steam pipe loss Q, a trap checker is used to measure the amount of steam discharged from the steam trap at the same time as the drain discharge, that is, the trap leak. Therefore, the steam pipe loss Q includes drain loss and trapley cloth.

  Note that the above-described correction coefficient may be applied to the entire steam pipe loss Q including the trapley cross, or the correction coefficient may be applied to the steam pipe loss Q excluding the trap leak cross.

As described above, according to the present embodiment, the steam pipe loss can be measured by measuring the amount of evaporation at no load. In this case, piping with a correction coefficient calculated on the basis of information on heat dissipation characteristics in the flow state of steam in the steam pipe 10 (characteristics in which the influence of the liquid film on the heat transfer coefficient in the pipe changes depending on the steam flow velocity (Reynolds number)). Loss is corrected. Therefore, the pipe loss measured by the no-load measurement becomes highly accurate in which the influence due to the fluctuation of the flow velocity accompanying the normal operation is accurately corrected. Therefore, according to the measuring method according to the present embodiment, the steam pipe loss can be measured with high accuracy.
Further, since the loss calculation based on the no-load evaporation amount is simple as in the measurement method of the present embodiment, there is an advantage that it is not necessary to modify the equipment.

  In the above description, the case where the Reynolds number obtained by calculation is used as an initial value in the case of obtaining the theoretical heat release qr during normal operation has been described as an example, but the present invention is not limited to this. For example, a value obtained by measuring the film thickness of the liquid film attached to the pipe wall of the steam pipe 10 with an ultrasonic sensor or the like may be used as the initial value.

  In this case, the Reynolds number is obtained from the measured thickness of the liquid film and the graph shown in FIG. Here, the graph shown in FIG. 3 has different Reynolds numbers depending on the shearing force. Therefore, the Reynolds number is obtained by setting the initial value of the shearing force τ to zero.

  Subsequently, the in-tube heat transfer coefficient is obtained from the Reynolds number obtained from the thickness of the liquid film using the graph shown in FIG. Here, in the graph shown in FIG. 4 as well, although the heat transfer coefficient in the pipe varies depending on the shearing force, the temporary heat transfer coefficient in the pipe is obtained by setting the initial value of the shearing force τ to zero, similarly to the Reynolds number.

  By replacing the temporary heat transfer coefficient obtained in this way with α1 in the above equation (2), a temporary heat release amount is obtained from the above equation (2) (step S1). Subsequently, the drain flow rate in the steam pipe is calculated from the provisional heat radiation amount. The following formula (4) is used to calculate the drain flow rate.

  q ′ × l = Δh × G (4)

here,
q ′: Temporary heat dissipation (W / m),
l: length of steam pipe (m),
Δh: heat of condensation at pipe pressure (evaporation heat; J / Kg)
G: Drain flow rate (Kg / s)

  That is, if the provisional heat radiation amount q ′ is obtained, the drain flow rate G is obtained from the known l and Δh.

  Subsequently, the shear force τ in the steam pipe in the no-load state is obtained again using the drain flow rate G obtained from the provisional heat radiation amount q ′. As shown in the above equation (3), the shear force τ is calculated from the difference between the vapor flow rate and the liquid film flow rate. Here, the steam flow velocity is obtained by proportionally distributing the flow rate of the entire pipe calculated based on the flow rate sensor 42 by the distance to the steam traps ST1, ST2, ST3, for example. Further, the liquid film flow rate can be calculated from the drain flow rate G. That is, the shearing force τ can be obtained again by using the above formula (3) (step S2).

  Subsequently, the Reynolds number, the in-tube heat transfer coefficient, and the shear force τ are obtained again using the shear force τ and the thickness of the liquid film obtained as described above (step S3). That is, step S1 to step S3 are sequentially repeated until the shearing force τ converges to a constant value.

In this way, the shear force τ in the steam pipe 10 during normal operation can be calculated with high accuracy. Therefore, heat dissipation characteristics (increase in thermal resistance due to the presence of a liquid film) in the flow state of steam during normal operation are taken into account by using the accurately calculated shear force τ and the measured value of the liquid film thickness. Obtain the heat transfer coefficient in the pipe. The theoretical heat release qr during normal operation may be calculated from the above equation (2) by replacing the in-tube heat transfer coefficient thus obtained with α ₁ in the above equation (2).

  In the above embodiment, the valve opening / closing control may be automatic or manual. Periodic loss measurement can be performed to verify damage to piping systems and deterioration of heat insulation performance.

  In the above description, the amount of water supplied to the steam production apparatus 20 is measured as a value related to the amount of evaporation in a substantially closed space. Alternatively, the amount of fuel used in the steam production apparatus 20 can be measured as a value related to the amount of evaporation in a substantially closed space. Further alternatively, the steam flow rate in the substantially closed space can be directly measured as a value for the amount of evaporation in the substantially closed space.

  FIG. 5 shows a modification of the loss measurement system. In FIG. 5, a plurality of steam lines 10A, 10B, and 10C corresponding to the plurality of load facilities 30A, 30B, and 30C are provided. The steam line 10A corresponding to the load facility 30A includes a plurality of steam traps STA1, STA2, and STA3, a flow rate sensor 42A, and a valve 27A. Similarly, the steam line 10B corresponding to the load facility 30B includes a plurality of steam traps STB1, STB2, STB3, a flow sensor 42B, and a valve 27B, and the steam line 10C corresponding to the load facility 30C includes a plurality of steams. Traps STC1, STC2, STC3, a flow sensor 42C, and a valve 27C are included. The valves 27A, 27B, and 27C are respectively near the entrance of the load facility 30A (30B and 30B) in the steam line 10A (10B and 10C) (the final steam trap STA3 (STB3 and STC3) and the load facility 30A (30B and 30B). Between).

  In FIG. 5, the loss of the entire steam system can be calculated by closing all the valves 27A, 27B, and 27C. In this case, as a value related to the amount of evaporation in a substantially closed space, the amount of water supplied to the steam production apparatus 20 is measured by the flow rate sensor 46, and the loss in the steam piping is determined from the obtained amount of water supply and the produced steam properties. It can be calculated and corrected using the correction factors described above. Alternatively, the loss in the steam pipe can be calculated by measuring the amount of fuel used in the steam production apparatus 20 as a value related to the amount of evaporation in a substantially closed space.

  Further, by closing the valve 27A and opening the valves 27B and 27C, the loss of the steam line corresponding to the load facility 30A can be calculated during the operation of the load facilities 30B and 30C. In this case, the loss in the steam line can be calculated by directly measuring the steam flow rate in the target steam line by the flow rate sensor 42A as a value related to the evaporation amount in the substantially closed space.

  Note that the heat dissipation amount q (W / m) per unit pipe length obtained from the measurement results is a value under the pipe diameter and the heat insulation diameter at the measurement point. You may spend it.

The size and heat insulation thickness of the steam pipe in the steam system may vary depending on the steam conditions (amount of steam used, pressure, temperature) of the load equipment. Even in such a case, if the heat radiation amount of a certain steam pipe is known, it is possible to obtain the heat radiation amount by performing correction based on differences in the pipe size, the insulation thickness, the pipe internal temperature, and the outside air temperature. is there. A correction calculation formula (5) for calculating a heat radiation amount corresponding to another pipe size and heat insulation thickness from a known heat radiation amount is shown below. This equation (5) can be derived from the above theoretical equation (2).
In the correction calculation formula (4), q ″: heat radiation amount per unit length (W / m) in another pipe, r1 ′: pipe outer diameter (m) of another pipe, r2 ′: another pipe Thermal insulation outer diameter (outer diameter of heat insulating material) (m), T0 ′: Internal temperature of another pipe (supply steam temperature) (° C.), T1 ′: Outside air temperature (air temperature) of another pipe (° C.) is there.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment. The numerical value used in the above description is an example, and the present invention is not limited to this. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Loss measurement system, 10 ... Steam pipe, 20 ... Steam production apparatus, 27 ... Valve, 30 ... Load equipment, 40 ... Control unit, 50 ... Calculation apparatus, 123 ... Converter, 124 ... CPU, 125 ... Memory, 127 ... input device, 128 ... display device.

Claims (8)

A system for measuring the loss of steam pipes connected to steam production equipment and load equipment,
A first device for creating a substantially closed space including at least a portion of the steam pipe;
A second device for controlling the amount of steam supplied from the steam producing device into the steam pipe so as to keep the pressure in the steam pipe substantially constant;
A third device for measuring a value relating to the amount of evaporation in the substantially closed space;
A fourth device for measuring the loss of the steam pipe using the measurement result of the third device;
A fifth device for correcting the measured value of the loss using information on heat dissipation corresponding to the flow state of the steam in the steam pipe ,
The fifth device, characterized that you correct the measured value of the loss by using a correction coefficient obtained from the tube heat transfer coefficient which corresponds to the liquid film thickness to adhere to the steam pipe that varies with the flow rate of the steam The steam pipe loss measurement system. The loss measurement system for a steam pipe according to claim 1, further comprising a liquid film measurement unit that measures a film thickness of the liquid film adhering to the steam pipe.   2. The apparatus according to claim 1, wherein the first device includes at least one of a means for stopping the load equipment and a means for closing a valve disposed in the steam pipe in the vicinity of an inlet of the load equipment. The steam pipe loss measurement system according to 2.   The fourth device comprises: means for measuring the amount of water supplied to the steam producing device; means for measuring the amount of fuel used in the steam producing device; and means for directly measuring the steam flow rate in the substantially closed space. The steam pipe loss measurement system according to any one of claims 1 to 3, comprising at least one. A method for measuring a loss of a steam pipe connected to a steam production apparatus and a load facility,
A first step of creating a substantially closed space including at least a portion of the steam pipe;
A second step of controlling the amount of steam supplied from the steam production apparatus into the steam pipe so as to keep the pressure in the steam pipe substantially constant;
A third step of measuring a value relating to the amount of evaporation in the substantially closed space;
A fourth step of measuring the loss of the steam pipe using the measurement result of the value related to the steam supply amount;
A fifth step of correcting the measured value of the loss using information on heat dissipation corresponding to the flow state of the steam in the steam pipe ,
Wherein in the fifth step, characterized that you correct the measured value of the loss by using a correction coefficient obtained from the tube heat transfer coefficient which corresponds to the liquid film thickness to adhere to the steam pipe that varies with the flow rate of the steam The steam pipe loss measurement method. 6. The steam pipe loss measuring method according to claim 5, wherein the fifth step includes a step of measuring a film thickness of the liquid film adhering to the steam pipe.   The first step includes at least one of a step of stopping the load facility and a step of closing a valve disposed in the steam pipe in the vicinity of an inlet of the load facility. 6. The steam pipe loss measurement method according to 6.   The fourth step includes a step of measuring the amount of water supplied to the steam production device, a step of measuring a fuel usage amount in the steam production device, and a step of directly measuring the steam flow rate in the substantially closed space. The steam pipe loss measuring method according to any one of claims 5 to 7, comprising at least one.

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