JP6481369B2 - Method for estimating the life of thermally expandable refractory materials - Google Patents

Description

  The present invention relates to a method for measuring the lifetime of a thermally expandable refractory material.

  For example, in a building such as a nuclear power plant, a large number of pipes and ducts are laid through through holes provided in a wall of the building. Various fluids are supplied and discharged through such piping. A seal structure is provided between the pipe and the through hole in order to ensure indoor or outdoor watertightness or airtightness.

  As an example of such a seal structure, one described in Patent Document 1 below is known. The sealing structure described in Patent Document 1 is provided on the outdoor side of a filling sealing material filled between the inner peripheral surface of the through hole and the outer peripheral surface of the arrangement member (pipe, etc.). And a stretchable member. With such a configuration, when the arrangement member is relatively displaced with respect to the through hole due to an external force such as an earthquake, the elastic member can follow the displacement, thereby ensuring the sealing performance before and after the earthquake. ing. In addition, in the case of the through-hole of the wall between a building, the elastic member may be installed in both surfaces of the filling sealing material.

  On the other hand, when pipes are passed through the through holes in the wall that partitions the building, there is also a demand to prevent the flame from burning into the adjacent building through the gap between the wall and the pipe. For this reason, an example in which a gap is filled with a thermally expandable refractory material is known. The heat-expandable refractory material includes a layered compound, and has a property of expanding in volume when exposed to a heat source having a specific temperature or higher. Specifically, intercalation compounds such as thermally expandable graphite and vermiculite are employed as such layered compounds. These intercalation compounds have a structure in which interlaminars having the property of gasifying and expanding by heat are interposed between layers. Interlayers exposed to heat gasify and expand when a certain temperature is reached. Thereby, the volume of a thermally expansible refractory material increases.

  If such a heat-expandable refractory material is applied to the through-hole entrance / exit of the wall of the building, the gap between the pipe and the inner wall of the through-hole caused by the earthquake etc. will expand the heat-expandable refractory material due to the heat at the time of fire Can be occluded. That is, it is possible to suppress the propagation of flame and heat to the adjacent building through this gap.

Japanese Patent Application Laid-Open No. 2014-5858

However, it has been conventionally known that it is difficult to estimate the life of the heat-expandable refractory material as described above. For example, in a plant such as the above-described nuclear power plant, the fluid supplied or discharged through a pipe communicating outside the building is often in a high temperature state. When the heat of such a high-temperature fluid reaches the intercalation compound contained in the heat-expandable refractory material, the intercalation compound may be heated to cause a desorption reaction of the interlaminar over a long period of time. When the elimination reaction proceeds, there is a concern that the expansion rate of the intercalation compound may be lower than the expected value, and there is a possibility that sufficient performance as a thermally expandable refractory material may not be exhibited when an actual disaster occurs. . Therefore, a technique that makes it possible to estimate the life of a thermally expandable refractory material easily and with high accuracy is desired.
In particular, there is no conventional method for estimating the expansion rate of an expanded refractory material under a specific temperature environment of an actual plant, for example, after being held for 5 years. In fact, there was no effective method other than conducting the test by holding at that temperature for 5 years.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an easy and highly accurate method for estimating the life of a heat-expandable refractory material.

In order to solve the above problems, the present invention employs the following means.
The thermal expansion refractory life estimation method according to one aspect of the present invention is a lifetime estimation method for a thermal expansion refractory material containing an intercalation compound, wherein the mass reduction rate and volume expansion when the intercalation compound is exposed to a specific temperature. When the intercalation compound is heated at a plurality of different heating rates, and the mass reduction rate calculation step for obtaining the allowable mass reduction rate that is the mass reduction rate in the required volume expansion rate by obtaining the relationship with the rate And a logarithm of each temperature increase rate and the temperature reached based on a measurement result in the temperature reached measurement step for each temperature increase rate, and a measurement result in the temperature reached measurement step. And the activation energy acquisition step of acquiring the slope of these plots as the value of the activation energy, and the activation energy based on the following equation: By substituting the value of Energy as an assignment value, including a service life calculation step of calculating the useful time to reach the permissible mass reduction rate at any temperature, the.
τ is the service life, ΔE is the activation energy, R is a gas constant, T is the ultimate temperature, and Φ is the rate of temperature increase.

  According to such a method, the time to reach the allowable mass reduction rate can be easily estimated from the value of the activation energy of the intercalation compound. Here, the allowable mass reduction rate is the value of the mass reduction rate when exhibiting the required volume expansion rate. That is, by obtaining the time to reach this allowable mass reduction rate, it is possible to estimate the time during which the required volume expansion rate can be maintained, that is, the lifetime.

  Furthermore, in the method for estimating the lifetime of the thermally expandable refractory material according to one aspect of the present invention, each step from the ultimate temperature measurement step to the activation energy acquisition step is performed a plurality of times for each of the plurality of different mass reduction rates. A repetition step of obtaining a plurality of values of the activation energy by repeating, a determination step of determining whether a difference between the values of the plurality of activation energy is equal to or less than a target threshold value, A substitution value determination step of determining a value of the activation energy as the substitution value in the durable time calculation step when it is determined in the determination step that the difference is equal to or less than the threshold value; Also good.

  According to such a method, the values of activation energies under different mass reduction rates are respectively obtained by the repetition step, and these activation energies are compared in subsequent determination steps. If the difference between these activation energies is less than or equal to the threshold value, it is recognized that they have undergone the same reaction mechanism, so that the accuracy and reliability of the result value obtained in the subsequent service life calculation step is further increased. Can do.

  ADVANTAGE OF THE INVENTION According to this invention, the lifetime estimation method of an easily and highly accurate heat-expandable refractory material can be provided.

It is sectional drawing of the seal structure which concerns on embodiment of this invention. It is an example of the graph which shows the relationship between the mass decreasing rate and the retention days (hours) in the thermally expansible refractory material which concerns on embodiment of this invention. It is an example of the graph which shows the relationship between the thermal expansion coefficient and mass reduction rate in the thermally expansible refractory material which concerns on embodiment of this invention. It is an example of the graph which shows the relationship between the mass decreasing rate for every temperature rising rate, and ultimate temperature in the thermally expansible refractory material which concerns on embodiment of this invention. It is an example of the graph which shows the relationship between the logarithm of the temperature increase rate in the thermally expansible refractory material which concerns on embodiment of this invention, and the reciprocal number of ultimate temperature. It is a graph which shows the relationship between the mass reduction | decrease rate of a thermally expansible refractory material in an Example of this invention, and retention days (hours). It is a graph which shows the relationship between the mass decreasing rate for every temperature increase rate of the thermally expansible refractory material in the Example of this invention, and ultimate temperature. It is a graph which shows the relationship between the logarithm of the temperature increase rate of the thermally expansible refractory material in the Example of this invention, and the reciprocal number of ultimate temperature. It is a step figure showing a life presumption method concerning an embodiment of the present invention. It is a step figure showing a life presumption method with confirmation of a single reaction mechanism concerning an embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings and mathematical formulas.
For example, in a building of a nuclear power generation facility, a life estimation method for a heat-expandable refractory material according to the present embodiment includes a through hole 11 of a wall portion 10 constituting the building, and an arrangement including pipes and ducts inserted through the through hole 11. The present invention is applied to the seal structure 100 provided between the installation member 12 (see FIG. 1A).

  The wall 10 is formed of concrete or the like, and separates the inside and outside of the building and the building. Assuming a case where a fire occurs after an earthquake, the surface on which the fire is generated is the surface 10A and the surface on which the fire is not generated is the surface 10B across the wall 10. Further, a through hole 11 is formed in the wall portion 10 to communicate the surface 10A side and the surface 10B side.

An arrangement member 12 formed in a tubular shape is inserted into the through hole 11. The opening diameter of the through hole 11 is formed larger than the outer diameter of the disposing member 12. Thereby, a certain gap is formed between the inner peripheral surface of the through hole 11 and the outer peripheral surface of the disposing member 12. A seal body 13 is provided in the gap between the through hole 11 and the outer peripheral surface of the disposing member 12 to ensure water tightness or air tightness between the indoor and outdoor buildings.
Furthermore, in order to prevent a flame from propagating to an adjacent building when a fire occurs after a further gap is generated between the arrangement member 12 and the inner wall of the through hole 11 due to an earthquake disaster or the like, A refractory material 14 is installed.

The seal body 13 includes a filling sealing material 13A, an elastic member 13C, and a breaker material 13B interposed between the filling sealing material 13A and the elastic member 13C. Further, a heat-expandable refractory material 14 is provided on the outside of the stretchable member 13C (that is, the side facing the indoor side or the outdoor side).
The seal body 13 and the thermally expandable refractory material 14 are fixed to the inner peripheral surface of the through hole 11 by a fixing material (not shown).

  The filling sealing material 13A is formed of an elastic foam material having heat resistance. The filling sealing material 13A is filled between the inner peripheral surface of the through-hole 11 and the disposing member 12 in a liquid phase state and then cured, whereby the inner peripheral surface of the through-hole 11 and the disposing member 12 are cured. It is a member that ensures water tightness by sealing the gap.

  The stretchable member 13C is a member having high stretchability provided on both the outdoor side and the indoor side of the filling sealing material 13A. The outer peripheral side of the elastic member 13 </ b> C is fixed to the inner peripheral surface of the through hole 11, and the inner peripheral side is fixed to the outer peripheral surface of the disposing member 12. Furthermore, it is desirable to apply a primer (not shown) between the elastic member 13C and the disposing member 12 and between the elastic member 13C and the through hole 11. With this primer, the adhesive strength between the elastic member 13C and the through hole 11 and the adhesive strength between the elastic member 13C and the disposing member 12 can be improved.

  The breaker material 13B is provided to allow relative movement between the filling seal material 13A and the elastic member 13C. As such a breaker material 13B, for example, foamed polyethylene molded into a plate shape, polytetrafluoroethylene film, release paper such as silicone processed paper, or the like is preferably used.

  The heat-expandable refractory material 14 has a property of expanding in volume when exposed to a heat source such as a flame. Examples of such a material include layered compounds such as thermally expandable graphite and vermiculite. Furthermore, the heat-expandable refractory material may have a matrix component for maintaining the shape as a component other than the above layered compound. The matrix component is desirably an organic component that disappears during combustion so as not to hinder expansion of the layered compound. As such materials, rubber materials such as butyl rubber, fluorine rubber, chloroprene rubber, and nitrile rubber, and oily materials such as mineral oil are particularly preferably used. The weight ratio of the layered compound in the thermally expandable refractory material is desirably 10 to 60% by weight.

  As the fixing material, for example, rock wool or mortar is used. Further, a heat retaining member may be provided between the seal body 13 and the thermally expandable refractory material 14 and the disposing member 12.

  The heat-expandable graphite is a carbon compound including at least a graphite layer in which hexagonal plate-like crystals composed of carbon atoms are laminated, and an interlayer inserted between these graphite layers (interlayers). As an example of the interlayer, for example, a compound containing sulfate and water can be considered.

  When such a heat-expandable graphite is heated, the above-mentioned interlayer is rapidly decomposed and gasified. The gasified interlayer sharply expands the interval between adjacent graphite layers. As a result, the volume of the thermally expandable graphite expands.

  Further, vermiculite is a clay mineral composed of a layer in which plate-like crystals made of silica alumina are laminated and an interlayer inserted between the layers. As an example of the interlayer, for example, ions of alkali metal or alkaline earth metal and water can be considered.

  Furthermore, the heat-expandable refractory material 14 expanded by heat such as a fire can hold the expanded shape for a certain time.

  Therefore, when the heat-expandable refractory material 14 is installed on both sides of the seal body 13, a gap 15 is generated between the seal body 13 and the heat-expandable refractory material 14 and the disposing member 12 due to the earthquake, and then a fire occurs. Even so, it is possible to suppress the propagation of the flame to the adjacent building. Specifically, as shown in FIG. 1B, the seal body 13 and the thermally expandable refractory material 14 are damaged or deformed by the earthquake, and at the same time, a fire is generated in the vicinity of the wall 10 (surface 10A side). In this case, the entire thermally expandable refractory material 14 (14A) before expansion exposed to the flame temperature expands in volume, thereby closing the entire through-hole 11 including the damaged portion (14B). Thereby, the propagation of the flame to the surface 10B side in the wall part 10 is prevented, and the fire spread to the adjacent building can be prevented.

    Here, in the above-described nuclear power plant or the like, the fluid flowing in the disposing member 12 is not higher than the decomposition temperature at which the thermal expansion refractory material 14 is decomposed, but is in a relatively high temperature state. Many. When such fluid heat reaches the intercalation compound in the heat-expandable refractory material 14, the interlaminar may gradually desorb from the intercalation compound during long-term operation. When this elimination reaction proceeds, there is a concern that the expansion coefficient of the intercalation compound is lower than a preset design value. In such a case, it is determined that the thermally expandable refractory material 14 has reached the end of its useful life.

  The lifetime estimation method of the thermally expandable refractory material 14 according to the present embodiment is used to estimate the lifetime of the thermally expandable refractory material 14 operated in an environment where the above-described desorption reaction can occur. Specifically, this lifetime estimation method includes a mass reduction rate calculation step, an ultimate temperature measurement step, an activation energy acquisition step, and a service life calculation step.

  In the mass reduction rate calculation step, a mass reduction rate is calculated when the thermally expandable refractory material is held for a long time at a constant environmental temperature. The mass reduction rate is a mass percent (wt%) of the mass reduction caused by the above desorption reaction with respect to the mass (initial mass) of the thermally expandable refractory material in the initial state. This mass reduction rate exhibits the following characteristics.

  As shown in FIG. 2, when the heat-expandable refractory material is held for a long time at a specific environmental temperature equal to or lower than the above decomposition temperature value, immediately after the start of the holding time, Mass reduction occurs due to desorption of substances adsorbed on the layered compound with an adsorption energy smaller than the activation energy, or low-temperature volatile components in the matrix. Next, mass loss accompanying delamination of the interlayer occurs.

Mass when a certain retention time has elapsed and desorption of a substance having an activation energy equal to or lower than the desorption activation energy corresponding to a certain holding temperature is completed and a specific mass reduction rate is reached. The decrease is substantially terminated.
In addition, as shown in FIG. 3, the coefficient of thermal expansion of the thermally expandable refractory material has a characteristic that depends on the value of the mass reduction rate. That is, when the mass reduction rate takes a specific value, the coefficient of thermal expansion is uniquely determined. Furthermore, when the value of the mass reduction rate increases, the thermal expansion coefficient tends to decrease.

  When the above-mentioned heat-expandable refractory material is applied, the necessary thermal expansion coefficient is determined in advance as the target thermal expansion coefficient X1 based on the opening diameter of the through holes and the amount of use of the heat-expandable refractory material. . That is, the heat-expandable refractory material expanded by the target coefficient of thermal expansion X1 can sufficiently close the through hole.

  Here, when the mass reduction rate takes a specific value as described above, the thermal expansion coefficient is uniquely determined. Therefore, based on a predetermined target thermal expansion coefficient X1, a mass reduction rate that can achieve this value (hereinafter defined as an allowable mass reduction rate wt1) is obtained. Thus, the mass reduction rate calculation step is completed.

  In order to actually determine the allowable mass reduction rate wt1, by holding the sample section of the thermally expandable refractory material at a constant environmental temperature, the graph shown in FIG. By burning at a temperature equal to or higher than the decomposition temperature of the object, for example, at 600 ° C., a graph showing the correlation between the coefficient of thermal expansion and the mass reduction rate shown in FIG. 3 can be obtained.

  Subsequently, an ultimate temperature measurement step is performed based on the above-described allowable mass reduction rate wt1. In the ultimate temperature measurement step, a temperature value indicating the allowable mass reduction rate wt1 is obtained. Specifically, the mass change of the sample section is measured while raising the ambient temperature of the sample section at a constant rate, and the temperature value at the time when the allowable mass reduction rate wt1 is reached is acquired as the reached temperature T. .

  In the present embodiment, as shown in FIG. 4, the ultimate temperatures T (T1, T2, T3, T4) are measured for each of a plurality (four) of temperature increase rates Φ1, Φ2, Φ3, and Φ4. .

  Subsequently, the subsequent activation energy acquisition step is executed based on each value of the reached temperature T. In this step, the activation energy when the interlayer of the thermally expandable refractory is desorbed is estimated based on the Ozawa method, which is a well-known method for non-constant temperature kinetic analysis. Details of this step will be described below.

  The Ozawa method shows that there is a relationship represented by the following equation (1) among the above-described temperature increase rate Φ, activation energy ΔE, and ultimate temperature T. In the formula (1), R represents a gas constant.

  Here, when the relationship between the logarithm (LogΦ) of each of the temperature rising speeds Φ1 to Φ4 and the reciprocal number (1 / T1, 1 / T2, 1 / T3, 1 / T4) of each of the reached temperatures T1 to T4 is plotted, A graph as shown in FIG. 5 is obtained. As shown in this graph, under a specific mass reduction rate (allowable mass reduction rate wt1), the relationship between the logarithm of the temperature increase rate Φ and the reciprocal of the ultimate temperature T has a constant slope A. It can be seen that it can be approximated as a function (linear approximation). That is, when the expression (1) is transformed into the expression (1 ′), LogΦ is expressed as a linear function of 1 / T having an inclination A of (0.4567 × ΔE) / R.

  Since the gas constant R is a given value, the activation energy value (ΔE1) when the allowable mass reduction rate wt1 is taken can be uniquely determined based on the value of the slope A. Thus, the activation energy acquisition step is completed.

  Subsequently, a subsequent service life calculation step is performed based on the activation energy value ΔE1. In this step, by substituting the activation energy value ΔE1 as a substitution value based on the equation (2) shown by the Ozawa method described above, the time τ until the allowable mass reduction rate wt1 at an arbitrary temperature is reached. calculate. As shown in the equation (2), in the Ozawa method, the time τ until reaching a predetermined mass reduction rate is determined based on the value of the activation energy ΔE and each value of the heating rate Φ. It is shown.

  The value of τ is obtained by substituting the activation energy ΔE and the temperature increase rate Φ into the above equation (2). Here, as described above, in the present embodiment, when the allowable mass reduction rate wt1 is reached, it is determined that the useful life of the thermally expandable refractory material has been reached. Therefore, this τ represents the service life of the thermally expandable refractory material, that is, the lifetime. Thus, all the steps of the method for estimating the lifetime of the thermally expandable refractory material according to the present embodiment are completed.

  According to such a method, based on the value of the activation energy of the thermally expandable refractory material, the life can be easily and accurately obtained by the analysis based on the Ozawa method described above. In addition, in this method, the only step that requires an actually measured value based on the experiment is the mass reduction rate calculation step for calculating the allowable mass reduction rate wt1, and therefore, the thermal expansion fire resistance in a relatively short time. The life (lifetime) of the material can be estimated.

  Thereby, in addition to the above-described seal body 13, for example, when a thermally expandable refractory material is applied to a part of the seal structure 100, the life of the thermally expandable refractory material can be easily and accurately known. A maintenance plan can be easily created.

  In addition, according to the above-described method, it is possible to design and manufacture a heat-expandable refractory material having a desired life (durable time) based on the environmental temperature under the application environment.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings and numerical formula, the concrete structure is not restricted to this embodiment, The change of the range which does not deviate from the summary of this invention, etc. are included.

  For example, in the above-described embodiment, the value of the activation energy ΔE is acquired by sequentially executing the mass reduction rate calculation step, the reached temperature measurement step, and the activation energy acquisition step once each. An example in which the subsequent service life calculation step is executed based on the above has been described.

However, in order to improve the estimation accuracy of activation energy, that is, the lifetime estimation accuracy, as shown in FIG. 10, a determination is made of a repetition step including a plurality of these temperature measurement steps and activation energy acquisition steps. You may perform a step and a substitution value determination step.
In addition, when changing the target thermal expansion magnification, it is necessary to perform again from the mass reduction rate calculation step.

  Specifically, in the repetition step, for each of a plurality of different mass reduction rates, the steps from the ultimate temperature measurement step to the activation energy acquisition step are repeated a plurality of times, thereby obtaining a plurality of activation energy values. get.

  Furthermore, a plurality of activation energy values obtained by the repetition step are compared with each other, and a step (determination step) for determining whether or not a difference between these values is equal to or less than a predetermined target threshold value is executed. . In this determination step, when it is determined that the values of the plurality of activation energies are equal to or less than the threshold value, the activation energy at the mass reduction rate to be estimated for life is selected from the plurality of activation energy values. Then, the value is substituted as a substitution value in the formula (2) referred to in the above-mentioned service life calculation step (substitution value determination step).

  In the method including the repetition step and the determination step as described above, when it is determined that the difference between the activation energy values is equal to or less than the threshold value, that is, when the activation energy values are determined to be substantially equal to each other. The mass reduction of the target heat-expandable refractory material in the range of the plurality of mass reduction rates can be regarded as occurring chemically through a single reaction mechanism (elimination reaction). Thereby, it is possible to further improve the reliability and accuracy of the service life value (τ) of the finally obtained heat-expandable refractory material.

  Next, examples of the present invention will be described. In this example, an example is shown in which a test for estimating the lifetime of a thermally expandable refractory material is performed based on the same method as in the above embodiment.

  In this test, thermally expandable graphite was used as the thermally expandable refractory material. First, the thermally expandable graphite was held for a certain period in a heating environment at a certain temperature, and the mass reduction rate was measured. The environmental temperature at this time was 110 ° C., and the holding period was 30 days. As shown in FIG. 6, after reaching the mass reduction rate of 3.5% on the 5th day of holding, it was found that almost no mass reduction occurred until the 30th day.

  Subsequently, the thermally expandable graphite held at 110 ° C. for 5 days and 30 days was burned in an electric furnace at 600 ° C. for 30 minutes, and the volume expansion coefficient (thermal expansion coefficient) before and after combustion was measured. It was confirmed that it was double. That is, if the mass reduction rate is less than 3.5 wt%, it is estimated that this thermally expandable graphite exhibits a thermal expansion coefficient of at least about 10 times.

  Subsequently, the thermally expandable graphite was heated at four different temperature rising rates, and the relationship between the respective mass reduction rates and temperatures was measured. Specifically, the heating rate Φ was set to four of 2.5, 5, 10, and 20. A measurement result is shown as a mass reduction rate curve of FIG. Each plot in FIG. 7 represents an inverse value (1 / T) of the reached temperature T of the thermally expandable graphite when the mass reduction rate is reached. From the results shown in FIG. 9, for example, the reciprocal value (1 / T) of the reached temperature when the mass reduction rate reaches 4 wt% under the temperature rising rate Φ = 5 (deg./min) is 0.00210. I understand that there is.

  Thus, it can be seen that the mass decrease rate curve shifts to the high temperature side as the temperature increase rate Φ increases. This shift amount is recognized to depend on the value of the activation energy required for the decomposition and gasification of the interlayer contained in the thermally expandable graphite.

  Next, when the natural logarithm (LogΦ) of the heating rate Φ and the reciprocal value (1 / T) of each achieved temperature are newly plotted from the mass reduction rate curve of FIG. 7, the result shown in FIG. 8 is obtained. As shown in the figure, it can be seen that the relationship between the value of LogΦ and the value of 1 / T can be linearly approximated at a specific mass reduction rate. The slope of this straight line depends on the value of the activation energy ΔE from the equation (1 ′) in the above-described embodiment. Furthermore, since the five approximate straight lines shown in FIG. 8 all have the same slope, it is recognized that the value of the activation energy ΔE is almost the same at any mass reduction rate. That is, it is confirmed that an elimination reaction having a single reaction mechanism occurs within a range including these five mass reduction rate values.

  Next, when the activation energy value ΔE is calculated based on the above equation (1 ′) from the slope of the approximate line when the mass reduction rate is 3.5 wt% in FIG. 8, ΔE≈235 kJ / mol. It became. Furthermore, when the value of ΔE was substituted into the above equation (2), the time to reach the mass reduction rate of 3.5 wt% under the ultimate temperature T = 110 (° C.) was calculated (service life time τ). The converted value τ ′ converted to days was τ′≈1470 (days).

  From the above results, it was estimated that the thermally expandable graphite used in this test can maintain a coefficient of thermal expansion of at least about 10 times over about 1470 days (about 4 years) when held at 110 ° C.

  Further, when the activation energy ΔE estimated by the above test is less than the above-mentioned 253 kJ / mol, in other words, when the delamination reaction of the interlayer is more likely to occur, the value of the service life τ is accordingly increased. Therefore, for example, when used as a thermally expandable refractory material in the above-described seal structure, the service life is shortened. On the other hand, when the value of ΔE is larger than 253 kJ / mol, since the value of the service life τ can be secured large, the service life can be extended. That is, it is possible to estimate the service life of the thermally expandable refractory material at the environmental temperature based on the value of the activation energy ΔE, and to increase the accuracy of the equipment maintenance plan accordingly.

100 ... Seal structure 10 ... Wall 10A ... Surface (fire occurrence side)
10B ... side (no fire occurrence side)
DESCRIPTION OF SYMBOLS 11 ... Through-hole 12 ... Arrangement member 13 ... Seal main body 14A ... Thermally expansible refractory material (before expansion)
14B ... Thermally expandable refractory material (after expansion)
15 ... Gap generated by the earthquake

Claims (2)

A method for estimating the lifetime of a thermally expandable refractory material containing an intercalation compound,
By calculating the relationship between the mass reduction rate and the volume expansion rate when the intercalation compound is exposed to a specific temperature, the mass reduction rate calculation for obtaining the allowable mass reduction rate which is the mass reduction rate in the required volume expansion rate is obtained. Steps,
An ultimate temperature measurement step for measuring the ultimate temperature at which the allowable mass reduction rate is reached when the intercalation compound is heated at a plurality of different temperature elevation rates, for each temperature elevation rate;
An activation energy acquisition step of plotting the relationship between the logarithm of each heating rate and the reciprocal of the ultimate temperature based on the measurement result in the ultimate temperature measurement step, and obtaining the slope of these plots as the value of the activation energy; ,
Based on the following formula, by substituting the value of the activation energy as a substitution value, a durable time calculating step for calculating a durable time until the allowable mass reduction rate at an arbitrary temperature is reached;
A method for estimating the life of a thermally expandable refractory material, comprising:

τ is the service life, ΔE is the activation energy, R is a gas constant, T is the ultimate temperature, and Φ is the rate of temperature increase. For each of a plurality of different mass reduction rates different from each other, by repeating each step from the ultimate temperature measurement step to the activation energy acquisition step multiple times, a repetition step of acquiring a plurality of activation energy values;
A determination step of determining whether a difference between the plurality of activation energy values is equal to or less than a target threshold;
In the determination step, when it is determined that the difference is equal to or less than the threshold value, a substitution value determination step that determines the value of the activation energy as the substitution value in the durable time calculation step;
The life estimation method of a thermally expandable refractory material according to claim 1, further comprising:

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