JP2014055694A - Steam supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam supply system capable of reducing heat loss.SOLUTION: A steam supply system 1 comprises: a steam generating device 2 which generates steam; a steam supply passage 3 which sends the steam generated by the steam generating device 2 to steam utilization equipment 50; a steam superheater 4 which is installed on the steam supply passage 3 and superheats the steam generated by the steam generating device 2; and a control device 5 which controls the steam superheater 4. The control device 5 controls the steam superheater 4 on the basis of a parameter with respect to a dryness fraction of the steam generated by the steam generating device 2 so that the steam superheated by the steam superheater 4 has a predetermined degree of superheat. Thus, the steam supply system 1 can stabilize the degree of superheat of the steam in accordance with the dryness fraction thereof and thereby restraining generation of drain. Therefore, the steam supply system 1 can reduce heat loss associated with a portion of the steam to be emitted when discharging the drain.

Description

  The present invention relates to a steam supply system.

  As a conventional steam supply system, for example, Patent Document 1 describes a steam transport pipe drain generation prevention device including a superheater, a steam transport pipe, a pressure detection means and a temperature detection means, and a controller. Yes. The superheater superheats the steam generated in the boiler. The steam transport pipe supplies the steam superheated by the superheater to the steam using device. The pressure detecting means and the temperature detecting means are provided immediately before the steam using device of the steam transport pipe. The controller inputs detection signals from the pressure detection means and the temperature detection means and issues a control signal for controlling the superheater. And this drain generation prevention device of the steam transport pipe detects, for example, the pressure and temperature immediately before the steam using device of the superheated steam flowing through the steam transport pipe, and sets the superheater so as to maintain a temperature slightly higher than the saturation temperature. Control.

JP 09-137911 A

  By the way, although the drain generation prevention device of the steam transport pipe described in Patent Document 1 described above suppresses the generation of drain in the steam transport pipe by the above configuration, for example, for the change in the dryness of steam, etc. Therefore, there is room for improvement, such as the effect of heat loss and overheating due to the response delay of superheat control.

  This invention is made | formed in view of said situation, Comprising: It aims at providing the steam supply system which can reduce a heat loss.

  In order to achieve the above object, a steam supply system according to the present invention includes a steam generator that generates steam, a steam supply path that supplies the steam generated by the steam generator to a steam-using device, and the steam A steam superheater that is provided on a supply path and superheats the steam generated by the steam generator; and a control device that controls the steam superheater, wherein the controller is generated by the steam generator. The steam superheater is controlled based on a parameter related to the degree of dryness of the steam, and the superheat degree of the steam superheated by the steam superheater is controlled to a predetermined superheat degree.

  Further, in the steam supply system, the steam generator generates steam by combustion heat when the fuel is combusted, and the parameter relating to the dryness of the steam generated by the steam generator is the steam The amount of combustion of the fuel in the generator and the pressure in the steam generator may be included.

  Further, in the steam supply system, the steam generator generates steam using an electric heater as a heat source, and the parameter relating to the dryness of the steam generated by the steam generator is the parameter in the steam generator. The output of an electric heater and the pressure in the said steam generator can be included.

  In the steam supply system, the steam generator has a detector that detects the concentration of water in the interior, and parameters related to the dryness of the steam generated by the steam generator are detected by the detector. It is possible to include the concentration of water inside the steam generator.

  Further, in the steam supply system, the steam generator has a measuring instrument that measures an operation time, and a parameter relating to the dryness of the steam generated by the steam generator is the steam measured by the instrument. It may include the operating time of the generator.

  The steam supply system according to the present invention controls the steam superheater based on a parameter related to the dryness of steam generated by the steam generator by the control device, and sets the superheat degree of the steam superheated by the steam superheater to a predetermined value. By controlling the superheat degree, it is possible to stabilize the superheat degree of the steam according to the dryness of the steam, so it is possible to suppress the generation of drain and to accompany the discharge of some steam at the time of drain discharge Heat loss can be reduced.

1 is a diagram illustrating a schematic configuration of a steam supply system according to Embodiment 1. FIG. It is a figure which shows schematic structure of the steam supply system which concerns on Embodiment 2. FIG.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

[Embodiment 1]
FIG. 1 is a diagram illustrating a schematic configuration of a steam supply system according to the first embodiment.

  A steam supply system 1 according to this embodiment shown in FIG. 1 is a system that supplies steam to various steam-using devices (load devices) 50 that operate using steam as a heating source or a power source. The steam supply system 1 of the present embodiment includes a boiler 2 as a steam generator, a steam supply path 3, a superheater 4 as a steam superheater, and a control device 5.

  The boiler 2 generates steam. The boiler 2 generates saturated steam St1 by various heat source methods. The saturated steam St1 is a steam in a range of steam containing slightly liquid water to 100% dry steam.

  As the boiler 2, various types such as a combustion boiler and an electric boiler can be used. FIG. 1 illustrates a combustion boiler 2 as an example. In the case of the combustion type, the boiler 2 is provided with a combustion device, which heats and evaporates can water in the can body 21 by combustion heat when fuel is combusted in the combustion device to generate saturated steam St1. . In the case of the combustion type, the combustion apparatus of the boiler 2 is supplied with fuel from the fuel supply path 22 via the fuel valve 23 and the like, and is supplied with combustion air from the air supply path 24. In this case, as the fuel, for example, gas fuel such as city gas, propane gas and biogas, liquid fuel such as heavy oil and kerosene are used. In the case of a combustion type, the boiler 2 can use various types, such as a once-through boiler, a furnace flue tube boiler, a water tube boiler, and the like. When the boiler 2 is an electric type, an electric heater is inserted into the can body 21, and the can water in the can body 21 is directly heated and evaporated by using the electric heater as a heat source to generate saturated steam St1. In the case of an electric type, the boiler 2 is configured not to include the fuel supply path 22, the fuel valve 23, and the air supply path 24 described above. The boiler 2 includes a can pressure sensor 9 described later, a concentration sensor 10 as a detector, and a boiler control device 25 that controls the operation of the boiler 2 based on detection values of these sensors and the like.

  The steam supply path 3 is a steam supply line for sending the steam generated by the boiler 2 to the steam using device 50. The steam supply path 3 includes a pipe, a flow rate adjustment valve, a check valve, a branch portion, and the like. The steam supply path 3 of the present embodiment includes at least a saturated steam pipe 31 and a superheated steam pipe 32.

  The saturated steam pipe 31 connects a steam outlet of the boiler 2 and a steam inlet of a superheater 4 described later. The saturated steam pipe 31 allows the steam to flow inside, and feeds the saturated steam St <b> 1 generated by the boiler 2 to the superheater 4. The superheated steam pipe 32 connects the steam outlet of the superheater 4 and the steam inlet of the steam using device 50. The superheated steam pipe 32 allows the steam to flow inside, and sends the superheated steam St2 heated by the superheater 4 to the steam using device 50 as described later. Note that both the saturated steam pipe 31 and the superheated steam pipe 32 may be configured by combining a plurality of pipes, a flow rate adjusting valve, a check valve, a branch portion, and the like.

The superheater 4 is a so-called super heater that is provided on the steam supply path 3 and superheats the steam generated by the boiler 2. As described above, the superheater 4 is provided between the saturated steam pipe 31 and the superheated steam pipe 32, the saturated steam pipe 31 is connected to the steam inlet, and the superheated steam pipe 32 is connected to the steam outlet. The superheater 4 superheats the saturated steam St1 sent from the boiler 2 through the saturated steam pipe 31 by various heat source methods, and generates superheated steam St2 having a temperature higher than the temperature of the saturated steam St1 having the same pressure. . The superheated steam St2 is a colorless and transparent H ₂ O gas obtained by heating the saturated steam St1 evaporated at a constant pressure saturation temperature to a higher temperature while maintaining a constant pressure.

  As the superheater 4, various types such as an electric superheater and a heat exchanger superheater can be used. In the case of an electric type, the superheater 4 uses the electric heater provided inside the superheater as a heat source to superheat the saturated steam St1 and generate superheated steam St2. In the case of a heat exchanger type, the superheater 4 uses the heat exchange medium supplied inside the superheater as a heat source, and heat-exchanges the heat exchange medium and the saturated steam St1, thereby superheating the saturated steam St1 and superheated steam St2. Is generated. In this case, as the heat exchange medium, for example, high-temperature heat medium oil from the heat medium boiler, combustion exhaust gas discharged from the boiler 2, high-pressure steam supplied from another boiler, or the like is used. In addition, the superheater 4 can also use a depressurizing superheater or the like.

  The superheater 4 is electrically connected to the control device 5, and the heating output is controlled by the control device 5. The heating output in the superheater 4 corresponds to the amount of heat (heating amount) given to the saturated steam St1 passing through the superheater 4. Here, in the case of an electric type, the heating output in the superheater 4 can be increased or decreased by adjusting the voltage (or energization amount) to the electric heater in the superheater 4. Further, in the case of a heat exchanger type, the heating output in the superheater 4 can be increased or decreased by adjusting the supply amount (flow rate) or temperature of the heat exchange medium supplied into the superheater 4. The superheater 4 increases the amount of heat applied to the saturated steam St1 as the heating output increases, and the degree of superheat of the generated superheated steam St2 increases. On the other hand, as the heating output of the superheater 4 decreases, the amount of heat applied to the saturated steam St1 decreases, and the degree of superheat of the generated superheated steam St2 decreases.

Here, the superheat degree of the superheated steam St2 is an index that represents the degree of superheat of the superheated steam St2 with respect to the saturated steam St1. As the degree of superheat of the superheated steam St2, for example, the difference between the temperature of the superheated steam St2 (superheated steam temperature) and the temperature of the saturated steam St1 (saturated steam temperature) can be used as represented by the following formula (1). .

Superheat degree (Deg) = superheated steam temperature (° C.) − Saturated steam temperature (° C.) (1)

  The control device 5 controls each part of the steam supply system 1 including the superheater 4. The control device 5 includes an electronic circuit mainly composed of a microcomputer including a CPU, a ROM, a RAM, and an interface.

  In the control device 5, for example, various sensors attached to various parts of the steam supply system 1 such as the pressure sensor 6, the outside air temperature sensor 7, and the superheated steam temperature sensor 8 are electrically connected, and an electrical signal corresponding to the detection result. Is entered. The control device 5 is electrically connected to a boiler control device 25 that controls each part of the boiler 2, and can exchange various electric signals between the control device 5 and the boiler control device 25. In the boiler control device 25, for example, various sensors such as the in-can pressure sensor 9 and the concentration sensor 10 are electrically connected, and an electric signal corresponding to the detection result is input. The in-can pressure sensor 9 detects the pressure in the can body 21 of the boiler 2. The concentration sensor 10 detects the concentration of the can water in the can 21 of the boiler 2. The concentration sensor 10 detects, for example, electrical conductivity of can water (1 / electric resistance of can water) [mS / m (milli Siemens per meter)]. The boiler water in the boiler 2 has a higher ion conductivity because it has a higher ion content and more easily conducts electricity. The concentration sensor 10 detects the concentration of the boiler water of the boiler 2 using this principle. The boiler control device 25 has a function of a timer (measuring instrument) that measures the operation time of the boiler 2. The boiler control device 25 controls the operation of the boiler 2 based on the detection value of the sensor or the like. For example, the operation of the boiler 2 based on the pressure in the can 21 is started, stopped, switched between combustion, and various abnormal values. Operations necessary for operation such as judgment, water supply, and blow are automatically performed. The control device 5 includes a pressure sensor and a concentration sensor different from the in-can pressure sensor 9 and the concentration sensor 10, and can independently obtain the pressure of the can body 21 and the concentration of the can water of the boiler 2. In this way, the superheat degree may be controlled based on the operation time of the boiler 2, the switching signal of the combustion device, and the like, the pressure in the can 21, and the concentration of the boiler water in the boiler 2.

  The control device 5 executes control programs stored in the storage unit on the basis of various input signals and various maps input from various sensors, thereby providing control signals to the respective parts of the steam supply system 1 including the superheater 4. To control these. The control device 5 can adjust the superheat degree of the superheated steam St2 superheated by the superheater 4 by controlling the superheater 4 and adjusting the heating output in the superheater 4. When the superheater 4 is an electric type, the control device 5 controls the voltage (input) to the electric heater in the superheater 4 to adjust the heating output in the superheater 4, and the superheated steam St 2. The superheat degree can be adjusted to a target superheat degree as a predetermined superheat degree. Moreover, when the superheater 4 is a heat exchanger type, the control device 5 controls the supply amount and temperature (input) of the heat exchange medium supplied into the superheater 4, thereby By adjusting the heating output, the superheat degree of the superheated steam St2 can be adjusted to the target superheat degree. At this time, for example, the control device 5 calculates the above formula (1) based on the saturated steam temperature obtained from the air supply pressure detected by the pressure sensor 6 and the superheated steam temperature detected by the superheated steam temperature sensor 8. It is possible to calculate the actual degree of superheat of the superheated steam St2 superheated by the superheater 4. Thereby, the control apparatus 5 can determine whether the superheat degree of the superheated steam St2 overheated with the superheater 4 is adjusted to the target superheat degree.

  Here, the target superheat degree is a target superheat degree of the superheated steam St2 heated by the superheater 4. Typically, this target superheat degree is a superheat degree at which no drain is generated before the steam reaches the steam using device 50 when the steam is supplied to the steam using device 50 in the steam supply path 3. The control device 5 is provided with a superheat degree setting unit 11 in terms of functional concept, and the superheat degree setting unit 11 sets a target superheat degree.

  The superheat degree setting unit 11 sets a target superheat degree based on a desired superheat degree allowed by the steam using device 50, a heat radiation amount of the steam supply path 3, and the like. Here, the steam having a desired superheat degree allowed by the steam using device 50 is a steam that is almost saturated when the steam reaches the steam using device 50 or a degree that does not affect the steam using device 50. This is a concept including slightly superheated steam having a superheat degree of. The amount of heat released from the steam supply path 3 corresponds to the amount of heat released before the steam is supplied to the steam using device 50 through the steam supply path 3. The heat release amount of the steam supply path 3 may be a heat release amount that has been investigated and measured in advance by a staff member, an operator, an operator, or the like as a fixed value, or may be appropriately calculated by the superheat degree setting unit 11. . The superheat degree setting unit 11 calculates the heat release amount of the steam supply path 3 according to, for example, information on the status of the steam supply path 3, an index representing the surrounding environment, an index representing the air supply pressure in the steam supply path 3, and the like. can do. Information on the status of the steam supply path 3 includes, for example, the overall length of the steam supply path 3, the laying position, the piping configuration such as the flange shape, the pipe thermal conductivity, the performance of the heat insulating material, the number of branch pipes, the number of various valves, Information on the operating state of other devices connected to the branch pipe, the operating state of various valves, and the like. The index representing the surrounding environment includes, for example, humidity, season, time zone, and the like in addition to the temperature around the steam supply path 3 detected by the outside air temperature sensor 7. The index representing the air supply pressure in the steam supply path 3 is, for example, the air supply pressure in the saturated steam pipe 31 detected by the pressure sensor 6.

  And the superheat degree setting part 11 is the superheater 4 based on the heat dissipation of the steam supply path 3 at the present time, the dryness of the steam supplied from the boiler 2, the superheat degree permitted by the steam using device 50, etc. The target superheat degree of the superheated steam St2 to be superheated is set. That is, when the superheat degree setting unit 11 sends the steam to the steam using device 50 through the steam supply path 3, even if the heat is dissipated by the current heat dissipation amount of the steam supply path 3, the steam is still in the steam using device. The target superheat degree is set so that drain does not occur before reaching 50 and is supplied to the steam-using device 50 at an allowable superheat degree. Further, the superheat degree setting unit 11 has the amount of heat of the superheated steam St2 superheated by the superheater 4 equal to the heat dissipation amount of the steam supply path 3 calculated above or the calculated steam supply path. The target superheat degree is set so that the heat quantity is a predetermined amount higher than the heat radiation quantity of 3. Here, the predetermined amount is, for example, the amount of heat corresponding to the slightly superheated steam that does not affect the steam using device 50.

  And the control apparatus 5 controls the superheater 4 based on the target superheat degree set as mentioned above, and adjusts the superheat degree of the superheated steam St2. Here, the control device 5 calculates the actual superheat degree at the present time according to the saturated steam temperature obtained from the air supply pressure detected by the pressure sensor 6 and the superheated steam temperature detected by the superheated steam temperature sensor 8. . And the control apparatus 5 controls the superheater 4 so that the calculated actual superheat degree at the present time may become said target superheat degree. In this case, the control device 5 controls the superheater 4 and adjusts the heating output in the superheater 4 to adjust the superheat degree of the superheated steam St2 superheated by the superheater 4 to the target superheat degree.

  As a result, the control device 5 makes the amount of heat of the superheated steam superheated by the superheater 4 equal to the calculated heat dissipation amount of the steam supply path 3 or from the calculated heat dissipation amount of the steam supply path 3. The amount of heat can be controlled to be high. In other words, the control device 5 superheats so that the saturated steam St1 generated by the boiler 2 becomes superheated steam St2 having a heat quantity equivalent to or slightly higher than the heat radiation amount of the steam supply path 3 as the heat quantity of the superheat. The device 4 can be controlled. As a result, the steam supply system 1 can send the superheat degree of the steam superheated by the superheater 4 to the steam using device 50 as the superheat degree at which no drain is generated.

  In the steam supply system 1 configured as described above, the saturated steam St1 generated by the boiler 2 is supplied to the superheater 4 via the saturated steam pipe 31 of the steam supply path 3. The steam supply system 1 superheats the saturated steam St1 sent by the superheater 4 to generate superheated steam St2. In the steam supply system 1, the superheated steam St <b> 2 generated by the superheater 4 is sent to the steam using device 50 through the superheated steam pipe 32 of the steam supply path 3.

  At this time, the control device 5 controls the superheater 4 and adjusts the heating output in the superheater 4, thereby determining the degree of superheat of the superheated steam St <b> 2 overheated by the superheater 4, the amount of heat released from the steam supply path 3, steam The target superheat degree is adjusted according to the dryness of the water and the allowable superheat degree. Thereby, the steam supply system 1 can supply heat to the steam using device 50 so that the steam is superheated in anticipation of heat dissipation in the steam supply path 3 and no drain is generated before reaching the steam using device 50. That is, even if the steam supply system 1 dissipates heat in the steam supply path 3 when the steam generated in the boiler 2 is supplied to the steam using device 50, the heat dissipation is generated by the heat (sensible heat) of the superheated steam St2. Can be complemented. Therefore, the steam supply system 1 can supply the steam using device 50 with steam having a desired superheat degree permitted by the steam using device 50 and before reaching the steam using device 50 in the steam supply path 3. It is possible to suppress a part of the water from being condensed, and it is possible to suppress the generation of drain.

  In the steam supply system 1, when steam is used in the steam using device 50, a part of the steam is condensed and drainage is generated. The drain condensed by the steam using device 50 is separated and collected by the steam trap 51 or the like. Then, the collected drain is supplied again into the boiler body 21 of the boiler 2 as the boiler water of the boiler 2.

  By the way, this steam supply system 1 has a possibility that the dryness of saturated steam St1 generated with the boiler 2 may change according to the operation state of the boiler 2, etc. In the steam supply system 1, the degree of dryness of the saturated steam St <b> 1 flowing into the superheater 4 may change, so that the superheated degree of the superheated steam St <b> 2 heated by the superheater 4 may not be stable. As a result, the steam supply system 1 cannot accurately adjust the degree of superheat of the superheated steam St2 heated by the superheater 4, and as a result, before the steam supply device 3 reaches the steam using device 50, the steam supply system 1 Condensation may occur and drainage may occur. In this case, in order to eliminate the influence of the inflow of drain into the steam-using device 50, the steam supply system 1 needs to discharge the generated drain to the outside of the steam supply path 3, for example. At this time, for example, when the steam supply system 1 discharges drain from a steam trap or the like, not only the drain but also a part of the steam may be discharged, which may cause heat loss.

  Therefore, the steam supply system 1 of the present embodiment controls the superheater 4 according to the dryness of the steam generated by the boiler 2 as described above, so that the superheater 4 always has a stable superheat degree. Superheated steam St2 is generated to suppress the generation of drain and to reduce heat loss due to partial steam discharge during drain discharge.

  Specifically, the control device 5 controls the superheater 4 based on a parameter related to the dryness of the steam generated by the boiler 2, and determines the superheat degree of the superheated steam St <b> 2 heated by the superheater 4 as the target. Control to superheat.

Here, the degree of dryness of the steam is an index that represents the weight ratio between the gas phase portion in the steam and the liquid phase, and more specifically, an index that represents the ratio of the dry saturated steam contained in the wet saturated steam. is there. The dryness of the steam can be expressed by, for example, the following formula (2).

Dryness = (1-wetness) = (1-liquid weight in steam / total steam weight) (2)

  In the overheating of the saturated steam St1 in the superheater 4, for example, the amount of heat for superheating 100% dry steam is determined by [specific heat × steam amount × superheat degree], but when steam contains moisture (ie, In the case of dryness <1), an additional amount of heat corresponding to the latent heat of steam is required. For this reason, the dryness of the saturated steam St1 flowing into the superheater 4 affects the overheating of the saturated steam St1 in the superheater 4. For example, when the superheater 4 superheats the saturated steam St1 having a high dryness and the saturated steam St1 having a low dryness at the same pressure to the same superheat degree, the superheater 4 has a lower dryness than the saturated steam St1 having a high dryness. A larger amount of heat is required when the saturated steam St1 is overheated.

  The control device 5 of the present embodiment controls the superheater 4 based on a parameter related to the dryness of the saturated steam St1, based on the influence of the dryness of the saturated steam St1 on the superheat of the saturated steam St1 in the superheater 4. .

  Here, the parameter related to the dryness of the saturated steam St1 is a physical quantity that causes a change in the dryness of the saturated steam St1, and is typically a physical quantity related to the operating state of the boiler 2. Examples of the physical quantity related to the operation state of the boiler 2 that affects the dryness include, for example, a physical quantity indicating the load state of the boiler 2, the pressure in the boiler 2, the quality of water supplied to the boiler 2, the concentration of the boiler water in the boiler 2, The operation time of the boiler 2 is mentioned. Here, the parameters related to the dryness of the saturated steam St1 are, for example, when the boiler 2 is a combustion type, the combustion amount of the boiler 2 and the pressure in the boiler 2, the concentration of the boiler water in the boiler 2, and the boiler 2 It includes at least one of driving hours and the like. The combustion amount of the boiler 2 can be detected based on the pressure of the fuel supply path 22, the opening / closing signal of the fuel valve 25 output from the boiler control device 25, the opening degree of the fuel valve 25, and the like. As the pressure in the boiler 2, the pressure in the can body 21 (hereinafter also referred to as “in-can pressure”) detected by the in-can pressure sensor 9 can be used. The quality of the water supplied to the boiler 2 may be one that has been inspected and acquired in advance or one that has been detected by various sensors. As the concentration of the can water inside the boiler 2, the concentration of the can water of the boiler 2 detected by the concentration sensor 10 can be used. As the operation time of the boiler 2, the operation time of the boiler 2 measured by the timer of the boiler control device 25 can be used. Further, for example, when the boiler 2 is an electric type, the output (input voltage) of the electric heater in the boiler 2 is used as a parameter relating to the dryness of the saturated steam St1 instead of the combustion amount of the boiler 2. it can.

  For example, when the boiler 2 is a combustion type, the dryness of the saturated steam St1 tends to be lower as the pressure inside the boiler 2 is lower and the combustion amount of the boiler 2 is larger (that is, the combustion load is higher). is there. On the other hand, the dryness of the saturated steam St1 tends to increase as the pressure inside the boiler of the boiler 2 is higher and the combustion amount of the boiler 2 is smaller (that is, the combustion load is lower). Similarly, when the boiler 2 is an electric type, the dryness of the saturated steam St1 is such that the lower the pressure in the can of the boiler 2 and the higher the output (input voltage) of the electric heater in the boiler 2 (that is, the electric output load is). It tends to be lower). On the other hand, the dryness of the saturated steam St1 tends to increase as the pressure inside the boiler of the boiler 2 is higher and the output of the electric heater in the boiler 2 is smaller (that is, the electrical output load is lower).

  Moreover, when the operation time becomes long, the boiler 2 tends to increase the concentration of impurities in the can water by repeating evaporation, and the foaming of the can water in the can body 21 tends to increase. And when the foaming of can water becomes large in the boiler 2, a phenomenon called so-called carry-over in which part of the can water is mixed into the steam occurs, and the dryness of the saturated steam St1 decreases. Thus, the dryness of the saturated steam St1 supplied from the boiler 2 changes according to the concentration of the can water. For this reason, the boiler 2 performs all blows which discharge all the can water in the boiler 2 when the operation of the boiler 2 is finished when the concentration of the can water exceeds the allowable value or the operation time exceeds the allowable time. , Replace all canned water with fresh water. In general, during operation of the boiler 2 in order to keep the permissible steam dryness, the boiler 2 is operated while the boiler 2 is operated so that the concentration of the can water is kept below the allowable value. Concentration blow (intermittent blow) operation to discharge part of the water and replace it with fresh water is performed automatically.

  And the dryness of saturated steam St1 tends to become low with the increase in the concentration of can water when the operation time of the boiler 2 becomes long, and when the operation time of the boiler 2 is short, the concentration of the can water rises too much. It tends to be high because it does not. This is also related to the quality of the water supplied to the boiler 2. If the electric conductivity of the water supply is high, the enrichment will increase even if the operation time of the boiler 2 is short, and the dryness will tend to decrease. If the electric conductivity is low, even if the operation time of the boiler 2 becomes long, the concentration does not advance and the dryness does not decrease. In addition, what is necessary is just to use the total operation time from the last all blows typically as the operation time of the boiler 2. FIG. In this case, the operation time of the boiler 2 is, for example, 1 hour when operated at 100% load for 1 hour, 0.5 hour when operated at 50% load for 1 hour, Just add up the time.

  The control device 5 of the present embodiment uses the combustion amount of the boiler 2 (output of the electric heater when the boiler 2 is an electric type), the pressure in the can, and the quality of water supplied to the boiler 2 as parameters relating to the dryness of the saturated steam St1. The control amount of the superheater 4 is controlled based on at least one of the concentration of the boiler water in the boiler 2, the operation time of the boiler 2, and the like. Here, the control amount of the superheater 4 is the heating output described above. When the superheater 4 is an electric type, the voltage (input) to the electric heater in the superheater 4 and the superheater 4 exchange heat. In the case of a vessel type, it is the supply amount and temperature of the heat exchange medium supplied into the superheater 4.

  More specifically, the control device 5 increases the heating output (control amount) of the superheater 4 as the dryness of the saturated steam St1, which changes according to the parameter related to the dryness as described above, is lower. On the other hand, the control device 5 decreases the heating output (control amount) of the superheater 4 as the dryness of the saturated steam St1 is higher.

  As an example, the superheat degree setting unit 11 calculates the dryness of the saturated steam St1 from a map or a mathematical model based on the parameter related to the dryness of the saturated steam St1. In this case, the degree of dryness of the saturated steam St1 is determined based on, for example, on-site evaluation, parameters related to the degree of dryness of the saturated steam St1 (combustion amount of the boiler 2 (output of the electric heater when the boiler 2 is an electric type), can) The internal pressure, the quality of water supplied to the boiler 2, the concentration of boiler water in the boiler 2, the operation time of the boiler 2) are set in advance, and the storage unit of the control device 5 as a map or mathematical model Stored in

  The superheat degree setting unit 11 sets the target superheat degree based on the current heat dissipation amount of the steam supply path 3, the calculated dryness of the saturated steam St <b> 1, and the superheat degree allowed by the steam using device 50. To do. And the control apparatus 5 calculates the heating output (control amount) of the superheater 4 based on this target superheat degree and dryness, and controls the superheater 4 so that it may become the calculated heating output. In this case, the heating output of the superheater 4 is set so as to increase as the dryness of the saturated steam St1 decreases. Note that the control device 5 directly superheats from a map or the like based on the parameters related to the dryness of the saturated steam St1, the heat dissipation amount of the steam supply path 3 at the present time, and the degree of superheat allowed by the steam using device 50. The heating output (control amount) of the heater 4 may be calculated, and the superheater 4 may be controlled so as to obtain the calculated heating output.

  The steam supply system 1 configured as described above is based on a parameter related to the dryness of steam generated by the boiler 2 when the superheat degree of the superheated steam St2 heated by the superheater 4 is adjusted to the target superheat degree. Thus, the superheater 4 is controlled. Thereby, even if the dryness of saturated steam St1 changes according to the operating state etc. of the boiler 2, and the dryness of saturated steam St1 which flows into the superheater 4 changes, the steam supply system 1 of the said dryness changes. By adjusting the heating output in the superheater 4 according to the change, the superheater 4 can give the amount of heat corresponding to the dryness of the saturated steam St1 to the saturated steam St1. As a result, the steam supply system 1 can accurately adjust the superheat degree of the superheated steam St2, and can generate the superheated steam St2 having a stable superheat degree. Therefore, the steam supply system 1 can more reliably stabilize the superheat degree of the superheated steam St2 heated by the superheater 4 at the target superheat degree, and can stably supply the steam having a desired superheat degree. .

  Therefore, the steam supply system 1 can suppress a part of the steam from condensing before reaching the steam using device 50 in the steam supply path 3, and can more reliably suppress the generation of drain. . Therefore, the steam supply system 1 can suppress the occurrence of heat loss due to the partial discharge of steam due to, for example, discharging the generated drain to the outside of the steam supply path 3. Further, since the steam supply system 1 can suppress the generation of drain in the steam supply path 3, for example, the number of steam traps on the steam supply path 3 can be reduced, and trap loss and trap pipe loss can be reduced. Etc. can be suppressed. Thereby, the steam supply system 1 can perform more efficient operation, can reduce the manufacturing cost, and can reduce the burden of maintenance and inspection. Furthermore, since the steam supply system 1 can suppress the generation of drain in the steam supply path 3, the steam flow rate in the steam supply path 3 can be improved, and thus the steam supply path 3 is configured. The pipe diameter can be reduced. Thereby, since the steam supply system 1 can reduce the heat radiation amount itself in the entire pipe constituting the steam supply path 3, the heat loss can be suppressed also in this respect, and more efficient operation can be performed. . Further, the steam supply system 1 regenerates drain sensible heat by re-evaporating the drain generated in the steam supply path 3 at the time of cold start with the superheated steam St2 superheated by the superheater 4, and the amount of drain Can also be reduced. Furthermore, since the steam supply system 1 can suppress the generation of drain in the steam supply path 3, the generation of so-called erosion (piping erosion), water hammer (water hammer action), and the like can also be suppressed. Further, since the steam supply system 1 can suppress the generation of drain in the steam supply path 3, for example, the detection accuracy of various sensors such as a flow meter (not shown) provided in the steam supply path 3 is reduced. Can be suppressed.

  According to the steam supply system 1 according to the embodiment described above, the boiler 2 that generates steam, the steam supply path 3 that supplies the steam generated by the boiler 2 to the steam using device 50, and the steam supply path 3 A superheater 4 that is provided above and superheats the steam generated by the boiler 2 and a control device 5 that controls the superheater 4 are provided. The control device 5 estimates the dryness based on a parameter relating to the dryness of the steam generated by the boiler 2, controls the superheater 4 based on the estimated dryness, and controls the steam superheated by the superheater 4. The superheat degree is controlled to a predetermined superheat degree (target superheat degree). Therefore, since the steam supply system 1 can stabilize the degree of superheat of the steam according to the dryness of the steam, it is possible to suppress the generation of drain and accompany the discharge of a part of the steam when draining. Heat loss can be reduced. Thereby, the steam supply system 1 can perform more efficient operation, for example.

[Embodiment 2]
FIG. 2 is a diagram illustrating a schematic configuration of a steam supply system according to the second embodiment. The steam supply system according to the second embodiment is different from the first embodiment in that it includes a bypass path and a flow rate adjusting device. In addition, about the structure, operation | movement, and effect which are common in embodiment mentioned above, the overlapping description is abbreviate | omitted as much as possible.

  In addition to the configuration of the steam supply system 1 (see FIG. 1), the steam supply system 201 of the present embodiment shown in FIG. 2 further includes a bypass pipe 210 as a bypass path and a flow rate control valve as a flow rate control device. 211.

  The bypass pipe 210 branches from the steam supply path 3, bypasses the superheater 4, and merges with the steam supply path 3 again. The bypass pipe 210 connects the upstream side of the superheater 4 and the downstream side of the superheater 4 with respect to the flow direction of the steam flowing through the steam supply path 3. Here, the bypass pipe 210 has one end connected to the saturated steam pipe 31 and branched from the saturated steam pipe 31, and the other end connected to the superheated steam pipe 32 and joined to the superheated steam pipe 32. In the bypass pipe 210, steam can flow inside, and a part of the saturated steam St <b> 1 generated in the boiler 2 can be sent from the saturated steam pipe 31 to the superheated steam pipe 32 by bypassing the superheater 4. . The bypass pipe 210 may be configured by combining a plurality of pipes.

  The flow rate adjustment valve 211 is controlled by the control device 5 and can adjust the flow rate of steam to the superheater 4 and the flow rate of steam to the bypass pipe 210. The flow rate adjusting valve 211 is provided on the bypass pipe 210, and the flow passage cross-sectional area of the bypass pipe 210 can be adjusted by adjusting the valve opening degree.

  Therefore, in the steam supply system 201, when the control device 5 controls the flow rate adjustment valve 211 to be adjusted to a predetermined valve opening, a part of the saturated steam St1 flows from the saturated steam pipe 31 to the bypass pipe 210. In the steam supply system 201, the saturated steam St <b> 1 flowing to the bypass pipe 210 bypasses the superheater 4, joins the superheated steam pipe 32, and is mixed with the superheated steam St <b> 2 superheated by the superheater 4. Thereby, the steam supply system 201 mixes the superheated steam St2 superheated by the superheater 4 and the saturated steam St1 that flows through the bypass pipe 210 and joins the superheated steam pipe 32, and the heat of the superheated steam St2 is saturated. Deprived of the steam St1, it becomes superheated steam St2 of a predetermined superheat degree and is sent to the steam using device 50.

  Note that the pressure sensor 6 of the present embodiment is provided in the saturated steam pipe 31 in the saturated steam pipe 31 at a detection position upstream of the branching portion between the saturated steam pipe 31 and the bypass pipe 210 in the steam flow direction. Detect air supply pressure. In addition, the superheated steam temperature sensor 8 is connected to the superheated steam pipe 32 at a detection position downstream from the junction of the superheated steam pipe 32 and the bypass pipe 210 with respect to the flow direction of the steam. The temperature of St2 is detected. The detection position of the superheated steam temperature sensor 8 can ignore the amount of heat dissipated in the superheated steam pipe 32 from the superheater 4 to the detection position, and the saturated steam St1 joined to the superheated steam pipe 32 from the bypass pipe 210 is superheater. 4 is set at a position where it is sufficiently mixed with the superheated steam St2 heated at 4. In the steam supply system 201, a mixing three-way valve or the like for sufficiently mixing the saturated steam St1 and the superheated steam St2 may be provided at a joining portion of the superheated steam pipe 32 and the bypass pipe 210.

  And the control apparatus 5 of this embodiment controls the superheater 4 and the flow control valve 211 based on the target superheat degree which the superheat degree setting part 11 set, and adjusts the superheat degree of the superheated steam St2. That is, the control device 5 calculates the actual superheat degree at the present time according to the saturated steam temperature obtained from the air supply pressure detected by the pressure sensor 6 and the superheated steam temperature detected by the superheated steam temperature sensor 8. Then, the control device 5 controls the superheater 4 and the flow rate adjustment valve 211 so that the calculated actual superheat degree at the present time becomes the target superheat degree. In this case, the control device 5 controls the superheater 4 and adjusts the heating output in the superheater 4, and also controls the flow rate adjustment valve 211 to flow the saturated steam St <b> 1 to the bypass pipe 210 (hereinafter, “ By adjusting the “bypass flow rate”, the superheat degree of the superheated steam St2 heated by the superheater 4 is adjusted to the target superheat degree.

  At this time, the control device 5 includes, as parameters relating to the dryness of the saturated steam St1, the combustion amount of the boiler 2 (output of the electric heater when the boiler 2 is an electric type), the pressure in the can, the quality of the water supplied to the boiler 2, The control amount of the superheater 4 and the control amount of the flow rate adjustment valve 211 are controlled based on at least one of the concentration of the can water of the boiler 2 and the operation time of the boiler 2. Here, the control amount of the superheater 4 is the heating output described above. When the superheater 4 is an electric type, the voltage (input) to the electric heater in the superheater 4 and the superheater 4 exchange heat. In the case of a vessel type, it is the supply amount and temperature (input) of the heat exchange medium supplied into the superheater 4. The control amount of the flow control valve 211 is the valve opening degree of the flow control valve 211.

  In this case, the superheat degree setting unit 11, similarly to the above, the degree of dryness of the saturated steam St <b> 1 calculated based on the current heat dissipation amount of the steam supply path 3, the parameter related to the dryness of the saturated steam St <b> 1, and steam use The target superheat degree is set based on the superheat degree allowed by the device 50. And the control apparatus 5 calculates the heating output (control amount) of the superheater 4 and the valve opening degree (control amount) of the flow control valve 211 based on this target superheat degree and dryness, and calculated heating output The superheater 4 is controlled such that the flow rate adjustment valve 211 is controlled so as to achieve the calculated valve opening.

  The control device 5 may control the flow rate adjustment valve 211 based on the superheated steam temperature detected by the superheated steam temperature sensor 8 to adjust the bypass flow rate. More specifically, the control device 5 controls the flow rate control valve 211 based on the deviation between the actual superheat degree of the steam and the target superheat degree according to the superheated steam temperature detected by the superheated steam temperature sensor 8, and bypasses it. You may make it adjust the flow volume of the vapor | steam to the piping 210. FIG.

  Since the steam supply system 201 according to the embodiment described above can suppress the generation of drain, it is possible to reduce heat loss due to partial steam discharge during drain discharge. , More efficient driving can be performed.

  Furthermore, according to the steam supply system 201 according to the embodiment described above, the control is performed by the bypass pipe 210 that branches from the steam supply path 3, bypasses the superheater 4, and merges with the steam supply path 3 again. And a flow rate adjusting valve 211 that can adjust the flow rate of the steam to the superheater 4 and the flow rate of the steam to the bypass pipe 210. Accordingly, the steam supply system 201 adjusts the degree of superheat by adjusting the flow rate of the saturated steam St1 that bypasses the superheater 4, so as to adjust the degree of superheat simply by adjusting the heating output of the superheater 4. Thus, for example, the degree of superheat of the superheated steam St2 can be adjusted with good responsiveness regardless of the influence of the retained heat of the entire apparatus such as the superheater 4.

  The steam supply system according to the above-described embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the claims. The steam supply system according to the present embodiment may be configured by appropriately combining the components of the embodiments described above.

  For example, the steam supply systems 1, 201 described above may include a saturated steam temperature sensor that detects the temperature of the saturated steam St <b> 1 fed through the saturated steam pipe 31 instead of the pressure sensor 6. In this case, the control device 5 obtains the air supply pressure in the saturated steam pipe 31 (the pressure of the saturated steam St1 supplied through the saturated steam pipe 31) from the temperature of the saturated steam St1 detected by the saturated steam temperature sensor. it can.

  Moreover, the steam supply systems 1 and 201 described above may include a plurality of systems of steam supply paths 3 (steam supply lines), a superheater 4, and the like, corresponding to the plurality of steam using devices 50. In this case, the steam supply systems 1, 201 are provided with a plurality of systems of steam supply paths 3 via steam headers or the like for pressure division for each of a plurality of systems (that is, for each steam supply line and for each steam using device 50). . In this case, the control device 5 controls the superheater 4 corresponding to each system based on the dryness of the saturated steam St1 flowing into the superheater 4 for each system, and is superheated by each superheater 4. What is necessary is just to control the superheat degree of the vapor | steam which is a predetermined superheat degree (target superheat degree) for every system | strain.

1,201 Steam supply system 2 Boiler (steam generator)
3 Steam supply path 4 Superheater (steam superheater)
5 Control Device 6 Pressure Sensor 7 Outside Air Temperature Sensor 8 Superheated Steam Temperature Sensor 9 Can Pressure Sensor 10 Concentration Sensor (Detector)
11 Superheat Degree Setting Unit 21 Can 22 Fuel Supply Path 23 Fuel Valve 24 Air Supply Path 25 Boiler Control Device (Measurement Instrument)
31 Saturated Steam Pipe 32 Superheated Steam Pipe 50 Steam-Used Equipment 51 Steam Trap 210 Bypass Pipe 211 Flow Control Valve St1 Saturated Steam St2 Superheated Steam

Claims (5)

A steam generator for generating steam;
A steam supply path for sending the steam generated by the steam generator to a steam using device;
A steam superheater that is provided on the steam supply path and superheats the steam generated by the steam generator;
A controller for controlling the steam superheater,
The control device controls the steam superheater based on a parameter related to the dryness of the steam generated by the steam generator, and controls the superheat degree of the steam superheated by the steam superheater to a predetermined superheat degree. It is characterized by
Steam supply system. The steam generator generates steam by the heat of combustion when fuel is burned,
Parameters relating to the dryness of the steam generated by the steam generator include the amount of fuel burned in the steam generator and the pressure in the steam generator.
The steam supply system according to claim 1. The steam generator generates steam using an electric heater as a heat source,
Parameters relating to the dryness of the steam generated by the steam generator include the output of the electric heater in the steam generator and the pressure in the steam generator.
The steam supply system according to claim 1. The steam generator has a detector for detecting the concentration of water inside,
The parameter relating to the dryness of the steam generated by the steam generator includes the concentration of water inside the steam generator detected by the detector.
The steam supply system according to any one of claims 1 to 3. The steam generator has a measuring instrument for measuring the operation time,
The parameter relating to the dryness of the steam generated by the steam generator includes an operation time of the steam generator measured by the measuring instrument.
The steam supply system according to any one of claims 1 to 4.

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