JP6209988B2 - Scale adhesion determination device - Google Patents

Description

  The present invention relates to a boiler scale adhesion determination device.

  2. Description of the Related Art Conventionally, steam boilers that have a plurality of water pipes and generate steam from water (canned water) supplied to the inside of the water pipe by heating the plurality of water pipes are widely used. In such a steam boiler, as the can water evaporates, hardness components contained in the can water are deposited and adhere to the inner surface of the water pipe as a scale. When the thickness of the scale attached to the water pipe increases, the heat applied to the water pipe becomes difficult to be transferred to the can water, and the temperature of the water pipe rises excessively, leading to the failure of the boiler. Therefore, a temperature sensor is disposed at a predetermined location of the water pipe, and the adhesion of the scale to the water pipe is determined based on the temperature of the water pipe measured by the temperature sensor (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 8-200705

  By the way, many scales adhere to the vicinity of the gas-liquid interface (water surface) inside the water pipe. And the water level of a water pipe changes with the operating condition of a boiler. Therefore, depending on the operation state of the boiler, the position where the temperature sensor is attached and the position where a lot of scales are attached may shift, and the temperature sensor may not be able to accurately determine the adhesion of the scales.

  Therefore, an object of the present invention is to provide a boiler scale adhesion determination device capable of accurately determining adhesion of scale to a water pipe.

  The present invention has a plurality of water pipes to which can water is supplied, and a scale for determining adhesion of scales to the plurality of water pipes in a boiler that generates steam from the can water by heating the plurality of water pipes A temperature sensor for measuring a surface temperature of the water pipe, a water level sensor for detecting a water level of canned water supplied to the water pipe, and a surface temperature of the water pipe measured by the temperature sensor is a reference temperature. A scale adhesion determination unit that determines that the scale has adhered when exceeding the difference, a difference calculation unit that calculates a difference in height between the water level detected by the water level sensor and the position where the temperature sensor is disposed, and The present invention relates to a scale adhesion determination device including a reference temperature correction unit that corrects the reference temperature based on a difference calculated by a difference calculation unit.

  Moreover, it is preferable that the difference calculation unit calculates the difference based on an average value of the water level of the can water for a predetermined period.

  According to the scale adhesion determination device of the present invention, it is possible to accurately determine the adhesion of the scale to the water pipe.

It is a figure which shows typically one Embodiment of a boiler provided with the scale adhesion determination apparatus of this invention. It is a figure which shows the state inside a water pipe typically, and is a figure which shows the state in which the water level of can water is substantially equal to the position where the temperature sensor is arrange | positioned. It is a figure which shows the state inside a water pipe typically, and is a figure which shows the state where the water level of can water is higher than the position where the temperature sensor is arrange | positioned.

Hereinafter, a preferred embodiment of a scale adhesion determination device of the present invention will be described with reference to the drawings.
The scale adhesion determination apparatus of this embodiment is incorporated in a steam boiler (hereinafter referred to as a boiler) that generates steam by heating water.
First, the overall configuration of the boiler 1 will be described with reference to FIG.
The boiler 1 includes a can body 10, a blower 20 that sends combustion air to the can body 10, an air supply duct 30 that connects the can body 10 and the blower 20, and combustion air circulates. A fuel supply device 40 for supplying gas, an exhaust pipe 50 through which combustion gas discharged from the can body 10 circulates, a water supply passage (not shown) for supplying water to the can body 10, and the combustion state of the boiler 1 The control apparatus 60 to control and the scale adhesion determination apparatus which determines adhesion of the scale to the boiler 1 are provided.

As shown in FIG. 1, the can 10 includes a boiler housing 11, a plurality of water pipes 12, a lower header 13, an upper header 14, and a burner 15.
The boiler housing | casing 11 comprises the external shape of the can 10, and is formed in the rectangular parallelepiped shape of planar view. An air supply port 16 is formed in the first side surface 11a located on one end side in the longitudinal direction of the boiler casing 11, and a second side surface 11b located on the other end side in the longitudinal direction of the boiler casing 11 is An exhaust port 17 is formed.

The plurality of water pipes 12 are disposed so as to extend in the vertical direction inside the boiler housing 11 and are disposed at predetermined intervals in the longitudinal direction and the width direction of the boiler housing 11.
The lower header 13 is disposed at the lower part of the boiler casing 11. The lower header 13 is connected to the lower ends of the plurality of water pipes 12.

The upper header 14 is disposed on the upper portion of the boiler casing 11. The upper header 14 is connected to the upper ends of the plurality of water pipes 12.
The burner 15 is disposed in the air supply port 16.

  The blower 20 includes a fan and a motor that rotates the fan. The blower 20 feeds combustion air into the can 10 as the fan rotates at a predetermined rotational speed.

  The air supply duct 30 has an upstream end connected to the blower 20 and a downstream end connected to the air supply port 16. The air supply duct 30 supplies the combustion air sent from the blower 20 to the can body 10.

The fuel supply device 40 includes a gas supply line 41, and an adjustment valve 42 and a nozzle 43 provided in the gas supply line.
The gas supply line 41 is connected to the air supply duct 30 and supplies fuel gas to the air supply duct 30.
The adjustment valve 42 adjusts the flow rate of the fuel gas supplied to the air supply duct 30.
The nozzle 43 is disposed at the tip of the gas supply line 41 and jets fuel gas into the air supply duct 30.

  The exhaust tube 50 is connected to the exhaust port 17. The exhaust tube 50 discharges the combustion gas generated by the combustion of the fuel gas inside the can 10.

The control device 60 changes the combustion state (combustion rate) of the boiler 1 according to the steam consumption by the load equipment to which the boiler 1 supplies steam, and adjusts the steam generation amount. More specifically, the control device 60 controls the combustion rate of the boiler 1 by controlling the supply amount of combustion air and the supply amount of fuel gas to the can body 10 by the blower 20.
Further, the control device 60 controls the water level of the can water inside the plurality of water pipes 12 according to the combustion state of the boiler 1. More specifically, since the can water boils violently when the combustion rate of the boiler 1 is high, the can water is easily accompanied by the steam generated in the water pipe 12 and collected in the upper header 14. Therefore, when the combustion rate of the boiler 1 is high, the control device 60 prevents the steam generated by lowering the water level of the can water from decreasing. On the other hand, when the combustion rate of the boiler 1 is low, the water level of the can water is increased to prevent overheating of the water pipe 12.
The control device 60 includes a scale adhesion determination unit 130, a difference calculation unit 140, and a reference temperature correction unit 150, which will be described later, and performs scale adhesion determination.

  According to the boiler 1 described above, the combustion air sent into the air supply duct 30 by the blower 20 is mixed with the fuel gas supplied from the gas supply line 41, and the mixed gas of the fuel gas and the combustion air is burner. 15 is injected into the inside of the can 10 and burned. Then, the water (canned water) supplied from the lower header 13 to the inside of the plurality of water pipes 12 is heated by the heat generated with the combustion of the mixed gas by the burner 15 to generate steam. The steam generated in the plurality of water pipes 12 is collected in the upper header 14 and then led to the outside through a steam outlet pipe (not shown). Further, the combustion gas generated by the combustion of the mixed gas is discharged from the exhaust tube 50 to the outside.

  By the way, in the inside of the water pipe 12, with the evaporation of the can water, the hardness component contained in the can water is deposited and adheres to the inner surface of the water pipe 12 as a scale. When the thickness of the scale attached to the water pipe 12 increases, the heat applied to the water pipe 12 becomes difficult to be transmitted to the can water, the temperature of the water pipe 12 rises excessively, leading to the failure of the boiler 1.

Therefore, in the boiler 1 of the present embodiment, it is determined whether or not the scale has adhered to the water pipe 12 by the scale adhesion determination device.
The scale adhesion determination device determines whether scale has adhered to the water pipe 12 based on the surface temperature of the water pipe 12.
In the present embodiment, the scale adhesion determination device is different from the temperature sensor 110 that measures the surface temperature of the water pipe 12, the water level sensor 120 that detects the water level of the can water supplied to the water pipe 12, and the scale adhesion determination unit 130. A calculation unit 140 and a reference temperature correction unit 150 are provided.

The temperature sensor 110 is disposed in any one of the plurality of water pipes 12 and measures the surface temperature of the water pipe 12. The temperature sensor 110 is disposed at a predetermined height in the predetermined water pipe 12 among the plurality of water pipes 12. The water pipe 12 to which the temperature sensor 110 is attached is determined according to the amount of scale attached, the thermal load, and the like. The temperature of the surface of the water pipe 12 measured by the temperature sensor 110 is transmitted to the control device 60 as a measurement signal.
The water level sensor 120 detects the water level of the can water stored in the water pipe 12. The water level detected by the water level sensor 120 is transmitted to the control device 60 as a detection signal.

  The scale adhesion determination unit 130 determines that the scale has adhered to the water pipe 12 when the surface temperature of the water pipe 12 measured by the temperature sensor 110 exceeds the reference temperature. That is, as the scale adheres to the water pipe 12, the temperature of the water pipe 12 rises because the heat applied to the water pipe 12 becomes difficult to be transmitted to the can water. Therefore, the scale adhesion determination unit 130 attaches the scale to the water pipe 12 when the surface temperature of the water pipe 12 measured by the temperature sensor 110 exceeds a predetermined reference temperature that does not reach when the scale is not attached. Is determined. In this case, the scale adhesion determination unit 130 notifies that the scale is adhered in a predetermined manner (for example, an alarm).

  The reference temperature is determined so that the boiler 1 is not damaged by overheating of the water pipe 12 even if the operation of the boiler 1 is continued for a predetermined period (for example, one week) after the scale adhesion determination unit 130 determines the adhesion of the scale. It is set with a certain margin for the superheat limit temperature of the water pipe 12 and stored in the control device 60.

  By the way, as schematically shown in FIGS. 2 and 3, the scale S adheres in the vicinity of the gas-liquid interface (water surface) inside the water pipe 12, and the amount of the scale S attached as the distance from the gas-liquid interface increases. Will decrease. As described above, the level of the can water inside the water pipe 12 varies depending on the combustion state of the boiler 1. Therefore, as shown in FIG. 2, when the water level L1 of the can water is in the vicinity of the position where the temperature sensor 110 is attached, the most superheated position (that is, the scale S adheres most by the temperature sensor 110). The temperature of the surface of the water pipe 12 at the position) can be measured, and the scale adhesion determination can be performed with high accuracy.

  On the other hand, as shown in FIG. 3, when the water level of the can water is away from the position where the temperature sensor 110 is attached, the temperature at the position where the scale S is most adhered cannot be measured by the temperature sensor 110. Therefore, the accuracy of scale adhesion determination may be reduced. That is, in such a case, even if the temperature measured by the temperature sensor 110 does not reach the reference temperature, the surface temperature of the water pipe 12 may reach the reference temperature at the position where the scale is most adhered. There is.

Therefore, in the scale adhesion determination apparatus of the present embodiment, the reference temperature is corrected by the difference calculation unit 140 and the reference temperature correction unit 150.
The difference calculation unit 140 calculates the difference in height between the water level detected by the water level sensor 120 and the position where the temperature sensor 110 is disposed. Specifically, information on the position where the temperature sensor 110 is arranged is stored in the control device 60, and the difference calculation unit 140 stores the information on the position of the temperature sensor 110 stored in the control device 60 and the water level sensor. Based on the water level measured by 120, the height difference is calculated.
Further, the difference calculation unit 140 may calculate the height difference based on an average value of a water level detected by the water level sensor 120 for a predetermined period (for example, one day).

The reference temperature correction unit 150 corrects the reference temperature to be determined by the scale adhesion determination unit 130 based on the height difference calculated by the difference calculation unit 140. More specifically, the control device 60 stores a relationship between the distance from the most superheated position where the scale adheres most and the temperature difference from the temperature of the most superheated position at the position of the distance as a table. And the reference temperature correction | amendment part 150 calculates | requires the temperature difference corresponding to the height difference (distance from the most superheat position) calculated by the difference calculation part 140 with reference to the table memorize | stored in the control apparatus 60, The reference temperature is corrected for the obtained temperature difference.
The reference temperature correction unit 150 corrects the reference temperature every predetermined period (for example, one day).

  Thus, by correcting the reference temperature based on the difference in height between the water level of the can water and the position where the temperature sensor 110 is disposed, the water level (the most superheated position) of the water pipe 12 depends on the combustion state of the boiler 1. Even if it changes, the adhesion of the scale can be determined based on the temperature of the surface of the water pipe 12 at the most superheated position. Therefore, more accurate scale adhesion determination can be performed.

  Further, when the difference calculation unit 140 calculates the difference based on the average value of the water level of the can water for a predetermined period, the operation tendency of the boiler 1 (for example, the boiler 1 normally has a combustion rate of 60%). Since the reference temperature can be corrected in accordance with, for example, combustion, scale adhesion can be determined in accordance with the usage status of each boiler 1.

  As mentioned above, although preferable one Embodiment of the scale adhesion determination apparatus of this invention was described, this invention is not restrict | limited to the above-mentioned embodiment, It can change suitably.

DESCRIPTION OF SYMBOLS 1 Boiler 12 Water pipe 110 Temperature sensor 120 Water level sensor 130 Scale adhesion determination part 140 Difference calculation part 150 Reference temperature correction part

Claims (2)

A scale adhesion determination device that has a plurality of water pipes to which can water is supplied and determines the adhesion of scales to the plurality of water pipes in a boiler that heats the plurality of water pipes and generates steam from the can water. There,
A temperature sensor for measuring the surface temperature of the water pipe;
A water level sensor for detecting the level of the can water supplied to the water pipe;
A scale adhesion determination unit that determines that a scale has adhered when the surface temperature of the water pipe measured by the temperature sensor exceeds a reference temperature;
A difference calculating unit that calculates a difference in height between a water level detected by the water level sensor and a position where the temperature sensor is disposed;
A scale adhesion determination device comprising: a reference temperature correction unit that corrects the reference temperature based on the difference calculated by the difference calculation unit.   The scale adhesion determination device according to claim 1, wherein the difference calculation unit calculates the difference based on an average value of the water level of the can water for a predetermined period.

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