JP2013029392A - Contact angle measurement device and prediction method for behavior of combustion ash in boiler furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact angle measurement device that can predict a wet state of combustion ashes in a boiler furnace by heating the interior of a chamber and cooling a pedestal, and a prediction method for behavior of combustion ashes in a boiler furnace.SOLUTION: There is provided a contact angle measurement device 1 which measures the contact angle of a sample 7 placed on a pedestal 6 provided in a container 4. The contact angle measurement device includes heating means 8 of heating the sample in the container; cooling means 9 of cooling the pedestal; first temperature detection means 10 of detecting temperature in the container; second temperature detection means 11 of detecting temperature of the pedestal; control means 14 of controlling the heating means and cooling means on the basis of detection results of the first temperature detection means and second temperature detection means; imaging means 12 of imaging a state of the sample heated by the heating means; and image analysis means 14 of determining the contact angle on the basis of an image picked up by the imaging means.

Description

  The present invention relates to a contact angle measuring device for measuring the wet state of a liquid with respect to a solid, particularly a contact angle measuring device for measuring a contact angle of a substance having a high melting point such as coal combustion ash and the behavior of combustion ash in a boiler furnace. It relates to the prediction method.

  When measuring the wet state of the liquid with respect to the solid, a contact angle measuring device is used. The contact angle measuring device has a pedestal and a test piece placed on the pedestal, and is dropped onto the test piece. The contact angle of the sample was measured by capturing the sample with a camera from the side and analyzing the acquired image.

  When measuring the contact angle of a sample that is solid at room temperature, such as slag, the test piece and sample are heated together by heating the pedestal, or the inside of an airtight chamber is tested. The contact angle of the sample was measured after the piece and the sample were heated together to melt the sample.

  One of the methods for measuring the contact angle after melting by heating is combustion ash of coal in a coal-fired boiler. In coal-fired boilers, the use of low-quality inferior coal is being promoted due to the expansion of the types of coal currently used, but inferior coal has a high ash content and a high alkali metal content, so the melting point of combustion ash Also lower. For this reason, there is a possibility that phenomena that hinder the stable operation of the boiler, such as inhibition of heat transfer and blockage of the flow path, accompanying the increase in the amount of combustion ash particles adhering to the furnace wall of the boiler may occur.

  Therefore, the wet state of the ash particles of the combustion ash on the furnace wall of the boiler is predicted, the cause of the ash particles adhering to the furnace wall of the boiler is elucidated, and the degree of ash particle adhesion to the furnace wall is predicted. There is a need for a way to do that.

  However, in the case of the conventional contact angle measuring device, the sample and the test piece contacting the sample in the chamber are integrally heated and cooled, so that the ash particles heated to the furnace atmosphere and the ash particles It was difficult to reproduce the in-furnace environment of the boiler in which the temperature of the furnace wall where the ash adheres was lower than the atmosphere in the furnace, and it was difficult to predict the wet state of the ash particles in the furnace.

  An illumination system that holds a substrate on a plate that can be heated by a resistance heater or that can be cooled using the Peltier effect, and projects a light and dark stripe pattern at equal intervals onto droplets dropped on the surface of the substrate. Provided, and the substrate and the droplet dropped onto the substrate are integrally heated or cooled by the plate, and point cloud data representing the 3D shape of the surface of the droplet is obtained from the stripe pattern obtained by the illumination system However, there is a device disclosed in Patent Document 1 as a contact angle measuring device for obtaining a contact angle of a droplet from the point cloud data.

JP 2003-148937 A

  In view of such circumstances, the present invention provides a contact angle measuring device and a boiler furnace that can predict the wet state of combustion ash in the boiler furnace by heating the chamber and cooling the pedestal. A method for predicting the behavior of combustion ash is provided.

  The present invention relates to a contact angle measuring apparatus for measuring a contact angle of a sample placed on a pedestal provided in a container, wherein the heating means heats the sample in the container, and the cooling means cools the pedestal. A first temperature detecting means for detecting the temperature in the container, a second temperature detecting means for detecting the temperature of the pedestal, and detection by the first temperature detecting means and the second temperature detecting means. Based on the result, a control means for controlling the heating means and the cooling means, an imaging means for imaging the state of the sample heated by the heating means, and an image for obtaining a contact angle based on the image captured by the imaging means The present invention relates to a contact angle measuring device comprising an analyzing means.

  The present invention also relates to a contact angle measuring apparatus further comprising a gas supply means for supplying a reducing gas into the container and a gas exhaust means for exhausting the atmosphere in the container.

  Furthermore, the present invention includes a step of heating the atmosphere in the container and the coal combustion ash placed on the pedestal by the heating means, a step of cooling the pedestal by the cooling means, the atmosphere in the container and the pedestal The temperature of the boiler is equal to the furnace atmosphere and the furnace wall of the boiler, the process of simulating the furnace environment of the boiler, the process of imaging the combustion ash melted on the pedestal by the imaging means, and the image analysis The present invention relates to a method for predicting the behavior of combustion ash in a boiler furnace having a step of measuring a contact angle of combustion ash based on an image picked up by means.

  According to the present invention, there is provided a contact angle measuring device for measuring a contact angle of a sample placed on a pedestal provided in a container, the heating means for heating the sample in the container, and the pedestal is cooled. Cooling means, first temperature detection means for detecting the temperature in the container, second temperature detection means for detecting the temperature of the pedestal, the first temperature detection means and the second temperature detection means A control means for controlling the heating means and the cooling means based on the detection result, an imaging means for imaging the state of the sample heated by the heating means, and a contact angle based on the image taken by the imaging means. It is possible to simulate the boiler furnace environment by predicting the degree of adhesion of ash particles to the furnace wall in the furnace, and to maintain the boiler. Easy time setting In addition, the amount of ash particles adhering to the furnace wall can be reduced by mixing different types of coal or changing operating conditions, etc., and maintenance costs can be reduced by extending the maintenance cycle. .

  According to the invention, the heating means heats the atmosphere in the container and the coal combustion ash placed on the pedestal; the cooling means cools the pedestal; the atmosphere in the container; and A step of reproducing the environment inside the boiler in a pseudo manner by making the temperature of the pedestal equivalent to the furnace atmosphere and the wall of the boiler, a step of imaging the combustion ash melted on the pedestal by an imaging means, and an image And a step of measuring the contact angle of the combustion ash based on the image taken by the analysis means, so that the degree of adhesion of the ash particles melted by the combustion ash to the furnace wall in the furnace can be predicted, and the boiler The maintenance period can be easily set, and the amount of ash particles adhering to the furnace wall can be reduced by mixing different types of coal or changing the operating conditions, thereby extending the maintenance cycle. Maintenance There is exhibited an excellent effect that it is possible to achieve a reduction of the door.

It is a schematic block diagram of the contact angle measuring apparatus which concerns on the 1st Example of this invention. It is explanatory drawing explaining the measurement of a contact angle by this contact angle measuring apparatus. It is explanatory drawing which shows the form of the ash particle in the furnace of a boiler. It is a graph which shows the relationship between the contact angle of the ash particle | grains in a boiler furnace, adhesion to a furnace wall, and a repulsion. It is a schematic block diagram of the contact angle measuring apparatus which concerns on the 2nd Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, referring to FIG. 1, a contact angle measuring apparatus according to a first embodiment of the present invention will be described.

  The contact angle measuring device 1 in the first embodiment is composed of a sample holding unit 2 and a sample measuring unit 3.

  The sample holder 2 has a chamber 4 that is an airtight container, and the chamber 4 is provided with a transmission window 5 formed of a heat resistant material such as heat resistant glass. A desired material, for example, an iron pedestal 6 made of the same material as a furnace wall 16 (see FIG. 3), which will be described later, is provided on the bottom surface of the chamber 4, and a liquid or solid sample 7 is placed on the pedestal 6. Placed. A heater 8 as a heating means is provided above the pedestal 6, and the heater 8 heats the atmosphere in the chamber 4 and the sample 7 by resistance heating or infrared heating. If the amount of the sample 7 placed on the pedestal 6 is extremely small, laser heating may be used as the heater 8. The pedestal 6 is made of a plurality of pedestals 6 made of different materials, and the pedestals 6 can be freely exchanged according to conditions.

  Inside the pedestal 6 is provided a cooling pipe 9 as a cooling means. The cooling pipe 9 is connected to a cooling medium supply means (not shown) for flowing a cooling medium such as cooling water and cooling gas, and the pedestal 6 is cooled by flowing the cooling medium through the cooling pipe 9. It has become. Instead of providing the cooling pipe 9 in the pedestal 6, the Peltier element may be brought into close contact with the lower surface of the pedestal 6 and the pedestal 6 may be cooled by the Peltier element.

  The sample holder 2 has a first thermocouple 10 as a first temperature detection means inserted from the outside into the chamber 4 and a second thermocouple 11 as a second temperature detection means. doing. The tip of the first thermocouple 10 extends into the space between the base 6 and the heater 8 so that the temperature in the chamber 4 heated by the heater 8 can be detected. The tip of the second thermocouple 11 is fixed to the end of the pedestal 6 so that the temperature of the pedestal 6 cooled by the cooling pipe 9 can be detected. The temperature detecting means may be a radiation thermometer. When a radiation thermometer is used, the temperature of the sample 7 and the pedestal 6 is detected.

  The sample measurement unit 3 includes a CCD camera as an imaging unit or a digital camera 12 having an imaging unit such as a CMOS sensor, a monitor 13 as a display unit, and a control arithmetic unit having an image analysis unit and a control unit (hereinafter, referred to as a calculation unit). (Referred to as PC) 14. The PC 14 is connected to the digital camera 12 and the monitor 13 by communication means such as a LAN, the heater 8, a cooling medium supply means (not shown), the first thermocouple 10, and the second. The heater 8 and the cooling medium supply means are controlled based on the temperatures detected by the first thermocouple 10 and the second thermocouple 11. It is like.

  The sample 7 on the pedestal 6 is captured from the side by the digital camera 12 through the transmission window 5, and the captured image is displayed on the monitor 13 and output to the PC 14. The contact angle of the sample 7 with respect to the pedestal 6 is calculated based on the captured image.

  Next, the case where the contact angle of the combustion ash of coal sampled from the inside of the sample 7, for example, a boiler is measured using the contact angle measuring apparatus 1 described above will be described.

  First, the sample 7 is placed on the pedestal 6, the sample 7 is heated by the heater 8, and a cooling medium is circulated through the cooling pipe 9.

  Based on the temperature detected by the first thermocouple 10, the PC 14 has a temperature of about 800 ° C. to 1500 ° C., for example, so that the atmosphere in the chamber 4 and the temperature of the sample 7 are equivalent to the furnace atmosphere in the boiler. By heating the heater 8, the sample 7 is melted, and the melted sample 7 spreads on the pedestal 6. At this time, the temperature of the cooling medium flowing through the cooling pipe 9 is controlled by the PC 14 to be, for example, about 500 ° C. at the maximum, and the temperature of the pedestal 6 is 300 ° C. to 800 ° C. which is equivalent to the furnace wall 16 of the boiler. It is about.

  When the sample 7 is melted, the digital camera 12 acquires images of the pedestal 6 and the sample 7 as shown in FIG. 2, and the acquired image is displayed on the monitor 13 and output to the PC 14. Is done.

  By analyzing the acquired image by the PC 14, the angle at which the sample 7 contacts the surface of the pedestal 6 is calculated, and the contact angle θ of the sample 7 with respect to the pedestal 6 that is lower than the surface of the sample 7 is obtained. Can do.

  The results obtained by the contact angle measuring device 1 described above can be used, for example, for predicting the behavior of coal combustion ash in a coal-fired boiler furnace.

  As one of the causes that the ash particles 15 of the combustion ash adhere to the furnace wall 16 of the boiler, the ash particles 15 melt in the boiler that has become high temperature, and the droplets of the molten ash particles 15 adhere to the furnace wall 16. Can be mentioned.

  FIG. 3 is a view showing the concept of adhesion and repulsion of the molten ash particles 15 to the furnace wall 16 of the boiler. The ash particles 15 are roughly divided into five forms in the process of colliding with the furnace wall 16. Can do.

  In FIG. 3, 15 a indicates a molten form before the ash particles 15 collide with the furnace wall 16, 15 b indicates a form in which the ash particles 15 are most spread due to the collision with the furnace wall 16, and 15 c indicates the furnace. The form immediately before the ash particles 15 fly from the furnace wall 16 due to the reaction caused by the collision with the wall 16 is shown. 15d shows a stable form in which the ash particles 15 fly from the furnace wall 16 and then adhere to the furnace wall 16 without being separated from the furnace wall 16, and 15r shows a stable form. 16 shows a form repelled by 16 and separated from the furnace wall 16.

  When the energy Ec in the form of the ash particles 15c immediately before flying from the furnace wall 16 is larger than the energy Er in the form of the ash particles 15r in a state away from the furnace wall 16, the ash particles 15 are repelled. Then, when separated from the furnace wall 16 and when Ec is smaller than Er, the ash particles 15 adhere to the furnace wall 16 without separating. That is, if (Ec-Er) / Er is larger than 0, the ash particles 15 repel and separate from the furnace wall 16, and if (Ec-Er) / Er is 0 or less, the ash particles 15 are separated from the furnace wall. 16 is attached.

  Further, among various factors such as a collision angle and a collision speed of the ash particles 15 against the furnace wall 16, a particle diameter of the ash particles 15, and a contact angle of the ash particles 15 with respect to the furnace wall 16, the contact angle is the furnace wall 16. It is presumed to be affected by adhesion and repulsion.

  FIG. 4 is a graph showing the relationship between the contact angle with the furnace wall 16 and (Ec-Er) / Er.

  As shown in FIG. 4, the ash particles 15 have (Ec−Er) / Er = 0 when the contact angle with the furnace wall 16 is α. Therefore, if the contact angle is larger than α, the ash particles 15 are all repelled and separated from the furnace wall 16, and if the contact angle is α or less, the ash particles 15 adhere to the furnace wall 16. Further, the smaller the contact angle of the ash particles 15 is less than α and the smaller the contact angle, the easier it is to adhere to the furnace wall 16.

  Therefore, by measuring the contact angle of the ash particles 15 of the combustion ash burned in the furnace of the boiler, whether the ash particles 15 adhere to the furnace wall 16 or whether the ash particles 15 adhere to the furnace wall 16. It is possible to predict how much it will adhere.

  As described above, in the first embodiment, the inside of the chamber 4 can be made a high temperature atmosphere by the heater 8 and the pedestal 6 on which the molten sample 7 is placed is cooled by the cooling pipe 9. Can do. In other words, it is possible to simulate the environment inside the furnace of the boiler in which the furnace is heated by the burner and the inside of the furnace becomes a high temperature atmosphere and the wall of the furnace is lower than the atmosphere in the furnace by the water cooling structure.

  Therefore, the composition of the combustion ash collected from the boiler or the combustion ash is analyzed, and the sample 7 prepared so that the composition matches is applied to the contact angle measuring device 1, and the contact angle of the combustion ash or sample 7 is applied. By measuring the above, the degree of adhesion of the ash particles 15 to the furnace wall 16 in the furnace can be predicted, and the maintenance time of the boiler can be easily set.

  Further, the contact angle of the ash particles 15 for each coal is measured, and the degree of adhesion of the ash particles 15 to the furnace wall 16 is predicted, thereby mixing different types of coal or changing the operating conditions of the boiler. The amount of ash particles 15 adhering to the furnace wall 16 can be reduced by such a process, and the maintenance cost can be reduced by extending the maintenance cycle.

  Next, a second embodiment of the present invention will be described with reference to FIG. 5 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  In the second embodiment, a gas supply pipe 17 and a gas exhaust pipe 18 are connected to the chamber 4. The gas supply pipe 17 is provided with a gas supply valve 19 and is connected to a reducing gas supply source (not shown). The gas supply pipe 17, the gas supply valve 19, and the reducing gas supply source constitute a gas supply means 21 so that a reducing gas such as CO or H 2 is supplied into the chamber 4 by the gas supply means 21. It has become.

  The gas exhaust pipe 18 is provided with a gas exhaust valve 22 and connected to an exhaust device (not shown) such as a vacuum pump. The gas exhaust pipe 18, the gas exhaust valve 22, and the exhaust device constitute a gas exhaust means 23, and the atmosphere in the chamber 4 is exhausted by the gas exhaust means 23. In the second embodiment, the chamber 4, the base 6, the heater 8, the cooling pipe 9, the first thermocouple 10, the second thermocouple 11, the gas supply means 21, and the gas exhaust means 23 hold the sample. Part 2 is configured.

  In the second embodiment, the gas supply valve 19, the gas exhaust valve 22, and the exhaust device are electrically connected to the PC 14. The PC 14 opens the gas supply valve 19, and the gas exhaust valve. Control is performed so that the reducing gas is supplied into the chamber 4 with the valve 22 closed or the gas supply valve 19 is closed and the gas exhaust valve 22 is opened to exhaust the reducing gas from the chamber 4.

  In the second embodiment, a reducing gas is supplied into the chamber 4 to make the inside of the chamber 4 a reducing atmosphere, so that the environment inside the furnace of the boiler reproduced in the chamber 4 is simulated. The furnace environment can be made closer, and the degree of adhesion of the ash particles 15 (see FIG. 3) to the furnace wall 16 (see FIG. 3) in the furnace can be predicted with higher accuracy.

DESCRIPTION OF SYMBOLS 1 Contact angle measuring device 2 Sample holding part 3 Sample measuring part 4 Chamber 6 Base 7 Sample 8 Heater 9 Cooling piping 10 1st thermocouple 11 2nd thermocouple 12 Digital camera 14 PC
21 Gas supply means 23 Gas exhaust means

Claims (3)

  A contact angle measuring device for measuring a contact angle of a sample placed on a pedestal provided in a container, the heating means for heating the sample in the container, the cooling means for cooling the pedestal, and the container On the basis of the detection results of the first temperature detection means for detecting the temperature inside, the second temperature detection means for detecting the temperature of the pedestal, the first temperature detection means and the second temperature detection means. Control means for controlling the heating means and the cooling means, imaging means for imaging the state of the sample heated by the heating means, and image analysis means for obtaining a contact angle based on the image captured by the imaging means A contact angle measuring device comprising:   The contact angle measuring device according to claim 1, further comprising a gas supply unit that supplies a reducing gas into the container and a gas exhaust unit that exhausts the atmosphere in the container.   A step of heating the atmosphere in the container by the heating means and the combustion ash of coal placed on the pedestal; a step of cooling the pedestal by the cooling means; and the temperature of the atmosphere in the container and the pedestal and the furnace of the boiler The process of simulating the furnace environment of the boiler by making it equivalent to the internal atmosphere and furnace wall, the process of imaging the combustion ash melted on the pedestal by the imaging means, and the image captured by the image analysis means A method for predicting the behavior of combustion ash in a boiler furnace, comprising the step of measuring the contact angle of combustion ash based on

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