JP5191410B2 - High temperature fluid heating device - Google Patents

Description

The present invention relates to a high-temperature fluid heating apparatus that heats a fluid to raise the temperature, and more specifically, heats a fluid flowing in a tubular body by heat transfer from the tubular body by inductively heating a conductive tubular body to generate heat. The present invention relates to a high-temperature fluid heating apparatus.
More specifically, the present invention relates to a high-temperature fluid heating apparatus suitable for heating a fluid to a high temperature exceeding the Curie temperature (magnetic transformation point) of the magnetic heat-resistant material forming the heat generating tube.
A superheated steam generator that further heats saturated steam such as steam to generate superheated steam is a typical example of a high-temperature fluid heating apparatus.

  A high-temperature fluid heating device that continuously generates a high-temperature fluid heats the fluid in the tube while passing the fluid through the hollow of the tube. Gas heating and electromagnetic induction heating are frequently used as heating means. However, even when using electromagnetic induction, an induction heating element is used for the tube, and high frequency is applied to the electromagnetic coil outside the tube. The so-called tube heat generation type that heats the tube body by energization (see, for example, Patent Document 1), adopts an electromagnetic induction non-heat generation body for the tube body, and inserts the electromagnetic induction heating element in the tube body to the outside of the tube. In other words, it is divided into a so-called in-tube heat generation type that heats the insert in the tube body by high-frequency energization of the electromagnetic coil (see, for example, Patent Documents 2 and 3).

  An electromagnetic induction non-heating element is made of a non-magnetic non-conductive heat-resistant material, and the non-magnetic non-conductive heat-resistant material exhibits non-magnetism in the sense that the magnetic transformation is not obvious because it has no or no magnetism and absorbs electromagnetic waves. It shows non-conductivity in the sense that there are more proportions to pass than it does, shows heat resistance in the sense that it is generally classified as suitable for use in areas where heat stress occurs, for example, Examples thereof include ceramic, FRP, and fluororesin (see Patent Document 2, paragraph 0012).

  The electromagnetic induction heating element is made of non-magnetic conductive heat-resistant material or magnetic conductive heat-resistant material, and if it matches the coil shape and high-frequency application conditions, it can absorb the electromagnetic wave and act as a heating element. It is shown. Non-magnetism and heat resistance have the same meaning as described above, and magnetism means that the onset of magnetic transformation and the Curie temperature are clear. Nonmagnetic conductive heat-resistant materials include, for example, austenitic stainless steel (Patent Document 1, paragraph 0011), carbon ceramic composite material (see Patent Document 2, paragraph 0019), carbon, graphite, platinum, nickel, mnemonic steel (Patent Document 3). (See the lower left column on page 5), Inconel (registered trademark), Hastelloy (registered trademark). Examples of the magnetic conductive heat-resistant material include martensitic stainless steel (see Patent Document 2, paragraph 0012), carbon steel (Patent Document 1, paragraph 0011), Kanthal (registered trademark) and other chromium / aluminum steel (Fe-Cr-). Al).

8A to 8D show a tubular body heat generation type superheated steam generator 10, where FIG. 8A is a left side view, FIG. 8B is a front view where a heat insulating material is removed, and FIG. Overall block diagram including temperature control circuit and other cooperating devices, (d) is a block diagram of the temperature control circuit,
This superheated steam generator 10 is described in the background art column of Patent Document 1, and its main body / mechanism (see FIGS. 8A and 8B) is an introduction section 11 for introducing saturated steam. And a heating unit 12 that heats the saturated steam to superheated steam, and a discharge unit 16 that discharges the superheated steam.

  The introduction part 11 and the discharge part 16 are formed of a funnel-like or trumpet-like cylinder in order to change the diameter of the steam flow path. The heating unit 12 includes a plurality of tube bodies 13 arranged in parallel and an induction coil 17 that is comprehensively wound around a group of tube bodies 13 via a heat insulating material (not shown). The tubular body 13 is made of a conductive material that is induction-heated by high-frequency energization to the induction coil 17, one end is connected to the introduction portion 11, the other end is connected to the discharge portion 16, and the hollow portion is a steam channel. It has become.

  Such superheated steam generator 10 is used for drying, volume reduction, cooking, sterilization and the like for waste oil, waste plastic, garbage, food, equipment, etc., for which the use of superheated steam is expanding. In many cases, a temperature control circuit is provided to supply superheated steam having a temperature suitable for the purpose of use. In the temperature control, feedback control is performed by PID calculation (proportional / integral / derivative), which is easy to use when there is a single control object, and the induction coil is set so that the detected temperature becomes the target temperature. 17 energization control is performed. The target of the temperature control is usually the discharge steam temperature or the temperature of the processing unit installed at the subsequent stage of the discharge unit.

  An example of feedback control of the discharge steam temperature is shown (see FIG. 8C). The superheated steam generator 10 is provided with a heating element thermometer 21, a discharge steam thermometer 22, and a temperature control circuit 23. . The heating element thermometer 21 is made of, for example, a thermocouple, and is attached to a substantially central position in the axial direction with respect to the outer peripheral surface of the tube body 13 serving as a heating element, detects the temperature of the heating element, and detects the detected temperature Ta. It is sent to the temperature control circuit 23. The discharge steam thermometer 22 is also composed of, for example, a thermocouple, which is attached to the discharge unit 16 or attached to a superheated steam supply pipe or the like immediately downstream thereof, and the temperature of the superheated steam discharged from the superheated steam generator 10. The detected temperature Tb is sent to the temperature control circuit 23.

  The temperature control circuit 23 (FIG. 8C) is a temperature controller (for example, commercially available) in which a comparison operation circuit (CMP.) For reporting and a PID operation circuit (PID) for tracking control are incorporated in one package. It is simply implemented using an electronic temperature controller. This temperature controller comprises two manual reference temperature setting means and two external signal input means, and inputs one set value and one external signal to the comparison operation circuit, and sets the other set values and Other external signals are input to the PID arithmetic circuit. The PID constant of the PID arithmetic circuit, that is, the proportional coefficient, the integral term coefficient, and the differential term coefficient can also be set manually or automatically (auto-tuning).

  Then, the temperature control circuit 23 adopting this is set with the set temperature (set value) for the comparison calculation circuit as the heating element upper limit temperature Sa, and the external signal to the comparison calculation circuit as the detection temperature Ta of the heating element thermometer 21. When the detected temperature Ta exceeds the heating element upper limit temperature Sa, an alarm signal Aa is output from the comparison operation circuit. The temperature control circuit 23 uses the set temperature for the PID calculation circuit as the discharge steam target temperature Gb, the external signal to the PID calculation circuit as the detection temperature Tb of the discharge steam thermometer 22, and the detection temperature Tb as the discharge steam target temperature. An energization command Ia for causing the high frequency power supply 24 to output a coil current Ib that approaches Gb is output from the comparison operation circuit.

The energization command Ia and the alarm signal Aa are sent from the temperature control circuit 23 to the high frequency power supply 24, and the high frequency power supply 24 applies the coil current Ib corresponding to the energization command Ia to the induction coil 17 of the heating unit 12 of the superheated steam generator 10. In addition to outputting, when the alarm signal Aa becomes significant, the output of the coil current Ib is forcibly stopped.
In addition (see FIG. 8C), a saturated steam generator 25 that supplies saturated steam is installed upstream of the superheated steam generator 10, and processing is performed using superheated steam downstream of the superheated steam generator 10. The processing part 26 of the superheated steam processing apparatus which performs is installed.

  When operating such a superheated steam generator 10 or the like, first, the heating element upper limit temperature Sa, the discharge steam target temperature Gb, and the PID constant are set in the temperature control circuit 23. The heating element upper limit temperature Sa is determined by the material of the tube body 13 and is set to, for example, about 600 ° C. to 650 ° C. when general-purpose austenitic stainless steel or carbon steel is used. The discharge steam target temperature Gb is determined by the required specifications of the superheated steam processing device 26, and is set to, for example, about 200 ° C. to 500 ° C. within a range lower than the heating element upper limit temperature Sa, depending on the purpose of use and use conditions. . The PID constant is basically determined based on the operating characteristics of the heating unit 12 and the high-frequency power source 24, but is also affected by the amount of steam supplied from the saturated steam generator 25 and the temperature of the discharged steam to the superheated steam processing device 26. It is also adjusted on site.

When the superheated steam generator 10 or the like is operated, saturated steam is supplied from the saturated steam generator 25 to the superheated steam generator 10, and the saturated steam is heated by the heating unit 12 of the superheated steam generator 10 to be superheated steam. Then, the superheated steam is supplied from the superheated steam generation device 10 to the superheated steam processing device 26, and a desired superheated steam treatment is performed in the superheated steam processing device 26.
At that time, if the PID constant is appropriately set and the amount of steam is in an appropriate range, an appropriate energization command Ia is issued from the temperature control circuit 23 to the high frequency power supply 24, and the induction coil of the superheated steam generator 10 is output from the high frequency power supply 24. 17, an appropriate coil current Ib is caused to flow, the detected temperature Tb of the discharge steam thermometer 22 becomes the discharge steam target temperature Gb, and the detected temperature Ta of the heating element thermometer 21 is satisfactory unless the discharge steam target temperature Gb is unreasonable. Remains below the heating element upper limit temperature Sa.

8 (e) to 8 (f) show another superheated steam generator 30 of a tubular body heat generation type, (e) is a left side view, and (f) is a front view of a place where a heat insulating material is removed.
This superheated steam generator 30 is described in the Example column of Patent Document 1, and differs from the superheated steam generator 10 described above in that the induction coil 17 is an induction coil 31 having a different winding state. Is a point.

The induction coil 31 is also made of a water-coolable copper tube or the like, and is wound around the outer periphery of the tube body 13 in the heating unit 12. However, the winding density is not uniform, and the coil is discharged roughly toward the introduction unit 11. It is dense near the part 16. The ratio depends on the temperature difference between the saturated steam and the superheated steam, but is preferably about [1: 2] to [1: 4], for example.
In this case, based on the density of the winding of the induction coil 31, the amount of heat input by induction heating is small near the introduction part 11 and large near the discharge part 16, so that the heat transfer efficiency from the tube 13 to the steam of the hollow part 14 is improved. The heating efficiency of the entire heating unit 12 is improved.

JP 2007-024336 A JP 2000-065312 A Japanese Patent Laid-Open No. 02-192687

  By the way, such superheated steam generators 10 and 30 of the tube exothermic type are currently used for steam generation of 700 ° C. or less, but high temperature heating exceeding that, for example, fluids to temperatures exceeding 800 ° C. or 1000 ° C. As a measure to meet this demand, a non-magnetic conductive heat-resistant material is used for the former heating element after multiple stages of the internal heating element in the superheated steam generator of the pipe heating type. However, it has been proposed to use a special carbon ceramic composite material for the heating element at the latter stage (see Patent Document 2). However, special carbon ceramic composite materials have poor durability at high temperatures, and non-magnetic non-conductive heat-resistant materials used in pipe heat generation type pipes also have low impact resistance and poor sealing performance at high temperatures. .

  On the other hand, in the tube heating type superheated steam generator, the non-magnetic non-conductive heat-resistant material or magnetic conductive heat-resistant material is used for the tube, not the non-magnetic non-conductive heat-resistant material. Inconvenience due to the use of can be avoided. Moreover, the cost increase of a high frequency power supply can be avoided by narrowing the high frequency application condition to one. Furthermore, nonmagnetic conductive heat-resistant materials and magnetic conductive heat-resistant materials are not only excellent in durability but also relatively inexpensive and easily available. For example, SUS310 or Inconel 600 is easy to use for nonmagnetic conductive heat-resistant materials, and Kanthal is easy to use for magnetic conductive heat-resistant materials. Therefore, it is desired to improve the tube heating type superheated steam generator so that it can be used up to a high temperature.

  However, in the case of the above-described non-magnetic conductive heat-resistant material that is easy to use, the long-term heat-resistant temperature, which is a practical upper limit temperature, is about 800 ° C., and the durability is insufficient at a temperature higher than that. In addition, in the case of the above-described easy-to-use magnetic conductive heat-resistant material, durability is good even at a high temperature such as 1000 ° C. or higher, but magnetic transformation occurs at a Curie temperature existing between normal temperature and 800 ° C. If the electromagnetic induction conditions of the induction coil and the high frequency power supply are matched to the lower temperature side than the Curie temperature, inconvenience occurs on the higher temperature side than the Curie temperature, and if the electromagnetic induction conditions of the induction coil and the high frequency power supply are matched to the higher temperature side than the Curie temperature, the Curie temperature Inconvenience occurs at lower temperatures.

  FIG. 9 is a graph showing the temperature rise characteristics of a tubular body heating type superheated steam generator in order to specifically explain these inconveniences, and (a) to (c) all show on the horizontal axis. Time is taken and temperature is taken on the vertical axis. (A) is a temperature rise characteristic graph when a non-magnetic conductive heat-resistant material is used for the electromagnetic induction heating element, and (b) is a physical property at a temperature lower than the Curie temperature using the magnetic conductive heat-resistant material for the electromagnetic induction heating element. Graph of temperature rise when the electromagnetic induction conditions are adapted, (c) shows the temperature rise when the magnetic induction heat generating material is made of a magnetic conductive heat-resistant material and the electromagnetic induction conditions are adapted to physical properties higher than the Curie temperature. It is a characteristic graph. Regarding the temperature rise characteristic graph in this figure and other figures, A indicates a Curie temperature of, for example, 600 ° C., B indicates a lower control target temperature set at, for example, 760 ° C., and C indicates, for example, a non-temperature of 800 ° C. The upper limit temperature of the magnetic conductive heat-resistant material is indicated, and D indicates a higher control target temperature set to 1000 ° C., for example.

  When a nonmagnetic conductive heat-resistant material such as SUS310 or Inconel 600 is used for the tubular body 13 which is an electromagnetic induction heating element (see FIG. 9A), electromagnetic induction such as the shape of the induction coil 17 and the output setting of the high frequency power supply 24 is performed. The condition is adapted to the physical properties at a temperature lower than the upper limit temperature C of the nonmagnetic conductive heat-resistant material and reaches the upper limit temperature C of the nonmagnetic conductive heat-resistant material after the time T1 has elapsed from the start time T0. It is used only at the control target temperature B lower than the temperature C (see the solid line graph in the figure). If the control target temperature D higher than the nonmagnetic conductive heat-resistant material upper limit temperature C is set in the temperature control circuit 23 ignoring the durability and damage, the time T2 (= T1 × ( 1.2 to 1.3)) After the passage, the control target temperature D is reached (see the broken line graph in the figure).

  Further, when a magnetic conductive heat-resistant material such as Kanthal is used for the tube body 13 and the shape of the coil 17 and the high-frequency application conditions are adapted to the physical properties lower than the Curie temperature A (see FIG. 9B), the Curie temperature A The temperature rises as quickly as in the case of the non-magnetic conductive heat-resistant material, but after exceeding the Curie temperature A, the electromagnetic induction conditions will not be met due to the change in physical properties of the tube 13, so the heating efficiency is reduced. The control target temperature D reaches the control target temperature D after the time T3 (= T2 × (3 to 6)) that is several times longer than the time T2 has elapsed (see the solid line graph in the figure). Note that the Curie temperature A may not be higher than the Curie temperature A depending on the type of magnetic conductive heat-resistant material and electromagnetic induction conditions (refer to the broken line graph in the figure). Although it is possible to raise the temperature exceeding this, it is inevitable that the time T3 to reach the control target temperature D is prolonged. In this case, the temperature controllability in a high temperature range exceeding the Curie temperature A is also deteriorated due to a decrease in heating efficiency.

  In contrast, in order to use a magnetic conductive heat-resistant material such as Kanthal for the tube body 13 and to adapt the shape of the coil 17 and the high-frequency application conditions to the physical properties higher than the Curie temperature A, for example, the induction coil 17 and the tube body 13 When the distance is shortened or the frequency of the output of the high frequency power supply 24 is changed (see FIG. 9C), the temperature rise characteristic and the temperature controllability are relatively good in the high temperature range exceeding the Curie temperature A, so that it becomes practical. However, since it takes a long time to reach the Curie temperature A from the start of energization, the time T4 (= T4 × (3 to 6)), which is several times longer than the time T2, elapses to reach the control target temperature D. (See the solid line graph in the figure).

As an improvement measure, it can be imagined that the time to reach the control target temperature D is shortened by switching the electromagnetic induction condition between a low temperature range that does not reach the Curie temperature A and a high temperature range that exceeds the Curie temperature A.
However, making the winding diameter of the coil 17 variable is difficult from the technical and cost viewpoints, and even if the output frequency of the high frequency power supply 24 can be switched, the cost of the high frequency power supply 24 is increased. Not desirable.
Therefore, the structure of the heating tube in the tube heating type high-temperature fluid heating device is devised so that the temperature rise time can be shortened even with the induction coil diameter fixed or with the induction coil diameter and applied power frequency fixed. This is a technical issue.

  The high-temperature fluid heating apparatus of the present invention (Solution means 1) was devised to solve such a problem, and an introduction part for introducing a fluid to be heated, a discharge part for discharging the heating fluid, , One end connected to the introduction portion and the other end connected to the discharge portion, and a hollow heat-generating tube body that forms a flow path, and a tube that surrounds the outer peripheral portion of the tube body and energizes the tube when energized In the high-temperature fluid heating apparatus including an induction coil for induction heating the body, an introduction side portion connected to the introduction portion of the tube is made of a nonmagnetic conductive heat-resistant material, and is connected to the discharge portion of the tube. The discharge side portion is made of a magnetic conductive heat resistant material, and the upper limit temperature of the nonmagnetic conductive heat resistant material is higher than the Curie temperature of the magnetic conductive heat resistant material.

  The high-temperature fluid heating device of the present invention is (the solution means 2), the high-temperature fluid heating device of the solution means 1, wherein the induction coil includes the introduction side portion of the tube body and the discharge side portion of the tube body. Is also fixed in a surrounding state.

  Furthermore, the high-temperature fluid heating apparatus of the present invention (Solution means 3) is the high-temperature fluid heating apparatus of the above-described solution means 1, wherein the induction coil is moved in the axial direction, and the discharge side portion of the tubular body When the detected temperature is lower than the Curie temperature of the magnetic conductive heat-resistant material, the induction coil is moved toward the introduction side portion of the tubular body by the moving mechanism. When the detected temperature is higher than the Curie temperature of the magnetic conductive heat-resistant material, the induction coil is moved by the moving mechanism while the detected temperature is lower than the upper limit temperature of the non-magnetic conductive heat-resistant material. The discharge side portion is moved toward the discharge side portion so that the induction coil surrounds the discharge side portion.

  The high-temperature fluid heating device of the present invention (solution 4) is the high-temperature fluid heating device of the solution 3, wherein the moving mechanism moves the induction coil with a fixed length. And

  The high-temperature fluid heating apparatus according to the present invention (Solution means 5) is the high-temperature fluid heating apparatus according to Solution 3, wherein the moving mechanism moves the induction coil by expanding and contracting. .

  In such a high-temperature fluid heating apparatus of the present invention (Solution 1, first claim 1), while the tube body heat generation type is taken over as the basic structure, the introduction side portion of the tube body is nonmagnetic conductive. By adopting a heat-resistant material and adopting a magnetic conductive heat-resistant material for the discharge side part of the tube, the electromagnetic induction conditions including the induction coil diameter are set to the Curie temperature of the magnetic conductive heat-resistant material on the discharge side of the tube. If it is adapted to the super physical properties, the electromagnetic induction conditions are compatible with the physical properties after loss of magnetism, so the physical properties of the non-magnetic conductive heat-resistant material on the introduction side of the tube are generally compatible. At the beginning of the time, the discharge side portion of the tube has a high magnetic resistance due to the shallow magnetic penetration depth, and most of the input power is concentrated, so that the temperature rises quickly and the introduction side portion also Although the power that contributes to heating is weak compared to its length, the discharge side part There is also steadily raising the temperature heat transfer from. When the temperature of the discharge side portion exceeds the Curie temperature, the electrical and magnetic characteristics of the entire tube body are substantially constant, so that the entire tube is efficiently heated and the temperature is increased more rapidly.

Further, if the fluid is supplied together with the temperature rise or at a later stage of the temperature rise, the temperature of the introduction side portion of the tube body can be kept lower than the temperature of the discharge side portion. Even under the constraint that the upper limit temperature of the magnetic conductive heat-resistant material is not exceeded, the discharge side portion of the tubular body can be heated to a high temperature exceeding the upper limit temperature of the non-magnetic conductive heat-resistant material.
As a result, the tube can be used up to a higher temperature than when only the non-magnetic conductive heat-resistant material is used, and the temperature rise time is shortened compared to when the tube is made only of the magnetic conductive heat-resistant material.
Therefore, according to the present invention, it is possible to realize a tubular body heat generation type high-temperature fluid heating apparatus capable of rapidly raising the temperature even when the induction coil diameter is fixed.

  Furthermore, by fixing the induction coil in a state surrounding the introduction side portion and the discharge side portion of the tubular body, the advantage of simple configuration is inherited from the tubular heating type, but in this case, if the fluid flow rate is small, Since the temperature suppression capability for the introduction side portion of the tubular body is weakened and the temperature of the introduction side portion of the tubular body easily exceeds the nonmagnetic conductive heat-resistant material upper limit temperature, it is difficult to use in a small flow rate region. Further, when the discharge steam temperature is near the Curie temperature, the temperature of the discharge side portion of the tube body is a mixture of the temperature equal to or higher than the Curie temperature and the temperature lower than the Curie temperature, so that electric control is difficult and heating efficiency is not optimal.

On the other hand, in the high-temperature fluid heating apparatus of the present invention (Solution means 2, initial claim 3), after introducing a moving mechanism for moving the induction coil in the axial direction, the induction coil is magnetic in the low temperature range. By removing from the conductive heat-resistant material and concentrating on the non-magnetic conductive heat-resistant material, it becomes easy to perform suitable heating over the entire portion facing the entire length of the induction coil. In addition, in the high temperature range, the induction coil is moved closer to the magnetic conductive heat-resistant material, so that the durability and strength of the non-magnetic conductive conductive heat-resistant material used for the introduction side of the tube are sufficient. Operation within the upper limit of the maintained temperature can be easily performed.
Therefore, according to the present invention, even if the induction coil diameter is fixed, the temperature control capability is high and stable in both high and low temperature ranges, and withstands long-term use without overheating even at high or low flow rates, and more quickly. It is possible to realize a tubular body heat generation type high-temperature fluid heating apparatus that raises the temperature.

Example 1 of the present invention shows the structure and operating characteristics of the high-temperature fluid heating device, (a) is a longitudinal front view of the main part with the heat insulating material and support legs removed, (b) is a circuit block diagram, (c) ) Is a temperature rise characteristic graph in which elapsed time is taken on the horizontal axis and temperature is taken on the vertical axis, and (d) is a temperature distribution graph in which the position on the tube is taken on the horizontal axis and the temperature is taken on the vertical axis. About Example 2 of this invention, the structure of a high temperature fluid heating apparatus is shown, (a) is a left view, (b) is the front view of the place which removed the heat insulating material, (c) is another high temperature fluid heating apparatus. The left side view, (d) is a front view of the place where the heat insulating material is removed. It is the temperature distribution graph which showed the subject at the time of small flow volume, took the position on a tubular body on the horizontal axis, and took temperature on the vertical axis | shaft. About Example 3 of this invention, the structure of a high temperature fluid heating apparatus is shown, (a) is a longitudinal front view of the principal part which removed the heat insulating material, the support leg, etc., (b) is a circuit block diagram, (c) is heat insulation. It is a vertical front view of the principal part which removed the material, the support leg, etc. The operating characteristics are shown, (a) is a temperature rise characteristic graph with elapsed time on the horizontal axis and temperature on the vertical axis, and (b) to (d) are vertical positions with the position on the tube taken on the horizontal axis. It is the temperature distribution graph which took temperature on the axis | shaft, (b) is the temperature distribution before coil movement, (c) is the temperature distribution after coil movement, (d) is the temperature distribution after coil movement which also reflected the influence of flow volume. It is. About Example 4 of this invention, the other structural example of a movement control is shown, and (a)-(b) all take the temperature of the nonmagnetic heat-resistant material part on the horizontal axis, and take the position of the induction coil on the vertical axis It is a characteristic graph, (a) is a simple hysteresis characteristic, (b) is the case of the characteristic which combined hysteresis with proportional control. About Example 5 of this invention, the structure of a high-temperature fluid heating apparatus is shown, (a)-(c) are all the vertical front views of the principal part which removed the heat insulating material, the support leg, etc., (a) is a coil movement The previous state, (b) is the state during coil movement, and (c) is the state after coil movement. The conventional superheated steam generator is shown, (a) is a left side view, (b) is a front view where the heat insulating material is removed, (c) is an overall block diagram including a temperature control circuit and other cooperating devices, (D) is a block diagram of a temperature control circuit, (e) is a left side view of another superheated steam generator, and (f) is a front view of a place where a heat insulating material is removed. The temperature rise characteristics of a conventional superheated steam generator are shown, and in each of (a) to (c), the horizontal axis is the elapsed time and the vertical axis is the temperature, and (a) is a non-magnetic conductive material for the electromagnetic induction heating element. Temperature rise characteristic graph when heat-resistant material is used, and (b) is a temperature rise characteristic graph when magnetically conductive heat-resistant material is used for the electromagnetic induction heating element and the electromagnetic induction conditions are adapted to physical properties lower than the Curie temperature. (C) is a temperature rise characteristic graph when a magnetic conductive heat-resistant material is used for the electromagnetic induction heating element and the electromagnetic induction conditions are adapted to the physical properties higher than the Curie temperature.

About the high temperature fluid heating apparatus of this invention, the specific form for implementing this is demonstrated by the following Examples 1-5.
The embodiment 1 shown in FIG. 1 embodies the above-described solution 1 (claims 1 and 2 at the beginning of the application), and the embodiment 2 shown in FIGS. 2 (a) and 2 (b) This is a modified example. FIG. 3 is an explanatory view of a further problem. In the third embodiment shown in FIGS. 4 to 5, the above-described solution 2 is embodied in a coil length fixing mode (claims 3 and 4 at the beginning of the application). Example 4 shown in FIGS. 6A and 6B is a modification thereof. Further, the fifth embodiment shown in FIG. 7 embodies the solution 2 described above in a coil expansion / contraction mode (claims 3 and 5 at the beginning of the application).
In the drawings, the same reference numerals are given to the same components as those in the prior art, and therefore, repeated explanations are omitted. Hereinafter, the differences from the prior art will be mainly described.

  A specific configuration of the high-temperature fluid heating apparatus according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a longitudinal front view of a main part of a high-temperature fluid heating apparatus 40 with the heat insulating material and support legs removed, and FIG. 1B is a block diagram of a control circuit and the like.

This high-temperature fluid heating device 40 is different from the superheated steam generator 10 described above in that the heating unit 12 equipped with a plurality of tubes 13 arranged in parallel has only one dissimilar material connecting tube 43. It is the point which becomes the heating part 42 equipped.
The pipe body 43 has been changed from a single material type to a dissimilar material connection pipe body, but the others have succeeded to those already described. Specifically, one end is connected to the introduction part 11 and the other end is connected to the discharge part 16 so that the hollow forms a flow path of the fluid to be heated, doubles as a heating element, and the tube 43 It is the same as in the past that the induction coil 17 is disposed in a place surrounding the outer peripheral portion, and that a baffle that disturbs the flow of fluid passing through the hollow portion of the tubular body may be inserted.

  A heat insulating material (not shown) interposed between the induction coil 17 and the tube 43, a temperature control circuit 23 responsible for energization of the induction coil 17, and a high-frequency power source 24 are also taken over. The set temperature for the PID calculation circuit of the temperature control circuit 23 is set to a control target temperature D of, for example, 1000 ° C. corresponding to the application purpose, and the detected temperature Tb of the discharge fluid thermometer 22 is brought close to the control target temperature D. The coil current Ib is supplied from the high frequency power supply 24 to the induction coil 17. In addition, although the illustration of the comparison arithmetic circuit portion that compares the detected temperature Ta of the thermometer 21 with the heating element upper limit temperature Sa and outputs the alarm signal Aa is omitted, it may be taken over.

  The dissimilar material connecting tube 43 is formed by rigidly and tightly connecting the introduction side portion 44 connected to the introduction portion 11 and the discharge side portion 45 continuous to the discharge portion 16 by welding or the like. A tube made of an easy-to-use nonmagnetic conductive heat-resistant material such as SUS310 or Inconel 600 is adopted, and a tube made of an easy-to-use magnetic conductive heat-resistant material such as Kanthal is adopted for the discharge side portion 45. Further, when these conductive heat-resistant materials are used, the selection condition is set so that the upper limit temperature C of the non-magnetic conductive heat-resistant material in the introduction side portion 44 is higher than the Curie temperature A of the magnetic conductive heat-resistant material in the discharge side portion 45. For example, the nonmagnetic conductive heat-resistant material upper limit temperature C is about 800 ° C., and the Curie temperature A is 600 ° C.

  If the control target temperature D for the fluid to be heated is higher than the conventional target temperature Gb and a long flow path is required for heat transfer, etc. The entire length of the coil 17 is also extended, and the induction coil 17 is fixed so as to surround the introduction side portion 44 of the dissimilar material connecting tube body 43 and the discharge side portion 45 of the dissimilar material connecting tube body 43. The length is appropriately adjusted according to the application purpose, but the number of induction coils 17 remains one, and a pair of power supply lines for the high-frequency power source 24 is sufficient. The ratio of the length of the introduction side portion 44 and the length of the discharge side portion 45 in the total length of the dissimilar material connecting pipe body 43 is also appropriately adjusted according to the application purpose, and is non-magnetic from the viewpoint of shortening the heating time and cost. The ratio of the length of the introduction side portion 44 of the conductive heat-resistant material is increased, and the ratio of the length of the discharge side portion 45 of the magnetic conductive heat-resistant material is increased from the viewpoint of preventing overheating.

The use mode and operation of the high-temperature fluid heating apparatus 40 of the first embodiment will be described with reference to the drawings. 1 (c) is a temperature rise characteristic graph in which elapsed time is taken on the horizontal axis and temperature is taken on the vertical axis, and (d) is a temperature distribution in which the position on the tube is taken on the horizontal axis and the temperature is taken on the vertical axis. It is a graph.
Since the basic usage and operation are the same as those of the conventional example described above, repeated description will be omitted, and hereinafter, the temperature rise characteristics improved by the introduction of the dissimilar material connecting pipe body 43 will be mainly described.

  Here again (see FIG. 1 (c)), A indicates the Curie temperature of, for example, 600 ° C., C indicates the upper limit temperature of the nonmagnetic conductive heat-resistant material, for example, 800 ° C., and D is a higher value set, for example, 1000 ° C. It is assumed that the control target temperature is indicated. Further, the diameter of the induction coil 17 and other coil shapes, the frequency of the output current of the high frequency power supply 24 and other high frequency application conditions are higher than the Curie temperature A related to the magnetic conductive heat-resistant material of the discharge side portion 45 of the dissimilar material connecting tube 43. It is assumed that adjustments have been made to suit the physical properties of the temperature. In addition, the induction coil 17 and the like and the introduction side portion 44 of the dissimilar material connecting pipe body 43 are substantially compatible with each other. It is assumed that the diameter is finely adjusted.

  When energization and fluid supply start at time T0, electromagnetic induction heating is performed. However, while the Curie temperature A is not reached, the input power concentrates on the discharge side portion 45 of the dissimilar material connecting tube 43. The discharge side portion 45 generates heat effectively, whereas the introduction side portion 44 does not generate much heat. Nevertheless, the introduction side portion 44 also rises in temperature due to heat generated by part of the power and heat conduction from the discharge side portion 45. The rate of temperature rise (see the solid line graph in the figure) is considerably faster than when the entire length of the tube is made of a magnetic conductive heat-resistant material (see the two-dot chain line in the figure). It approaches when it is made a magnetic conductive heat-resistant material (see the one-dot chain line graph in the figure).

  Then, when the temperature of the discharge side portion 45 reaches the Curie temperature A and exceeds it, the discharge side portion 45 also conforms to the electromagnetic induction conditions due to the change in physical properties of the discharge side portion 45, so that the dissimilar material connecting pipe Since the body 43 generates heat effectively as a whole, the heating rate is accelerated and the heating time is shortened. The time to reach the nonmagnetic conductive heat-resistant material upper limit temperature C is a time T5 (= T1 × (1.3 to 1.7)) that is about several tenths of the conventional time T1, and the time to reach the control target temperature D Is a time T6 (= T1 × (1.2 to 1.6)) which is longer by several tens of the conventional virtual time T2. These times T5 and T6 are reduced to a fraction of ((1 / (2-4)) compared to times T3 and T4 when a nonmagnetic conductive heat-resistant material or a magnetic conductive heat-resistant material is employed alone. Has been.

  In addition, if the flow rate of the fluid to be heated is not too high and not too low and is within an appropriate range (see FIG. 1D), the temperature of the fluid increases monotonically from the introduction unit 11 to the discharge unit 16, so that the fluid The temperature distribution in the dissimilar material connecting pipe 43 that conducts heat while passing the gas also monotonously increases from the introduction side portion 44 to the discharge side portion 45. Therefore, the temperature of the introduction side portion 44 does not exceed the upper limit temperature C of the non-magnetic conductive heat-resistant material even if it is a connecting portion with the discharge side portion 45 that becomes the hottest, so the introduction side portion 44 can be used for a long time. It will endure. In addition, the discharge side part 45 whose upper limit temperature is higher than the control target temperature D can withstand long-term use regardless of the presence or absence of fluid.

  A specific configuration of the high-temperature fluid heating apparatus according to the second embodiment of the present invention will be described with reference to the drawings. FIGS. 2A and 2B show the main structure of the high-temperature fluid heating device 47, where FIG. 2A is a left side view, and FIG. 2 (c) and 2 (d) show the main structure of another high-temperature fluid heating device 48, (c) is a left side view, and (d) is a front view with the heat insulating material removed. .

The high-temperature fluid heating device 48 is different from the high-temperature fluid heating device 47 in that the induction coil 17 is an induction coil 49 having a different winding state. Although the winding density of the induction coil 17 is constant, the winding density of the induction coil 49 is not uniform as in the induction coil 31 described above. Closer to the discharge part 16, it is rough. With this configuration, the concentration of input power while the temperature of the magnetic conductive heat-resistant material does not reach the Curie temperature is alleviated, and the temperature rise rate when the entire length of the tube is made of a non-magnetic conductive heat-resistant material can be made closer. It becomes possible.
The high-temperature fluid heating devices 47 and 48 are different from the high-temperature fluid heating device 40 of the first embodiment described above in that a large number of different-material connecting tube bodies 43 are arranged in parallel.
In this case, the advantage of improving the efficiency of induction heating by arranging a plurality of heat generating tubes in parallel, and the advantage of improving the heating rate by changing the coil density are also added.

[Problems at a small flow rate according to Examples 1 and 2]
FIG. 3 is a temperature distribution graph in which the position on the dissimilar material connecting tube 43 is taken on the horizontal axis and the temperature of each position is taken on the vertical axis, which may occur when the high-temperature fluid heating device 40 is used at a small flow rate. Indicates a problem.

  In the case of the high-temperature fluid heating device 40, the induction coil 17 is always fixed and the introduction side portion 44 and the discharge side portion 45 of the dissimilar material connecting tube 43 surround the outer peripheral portion. Is maintained at the control target temperature D, if the flow rate of the fluid to be heated is reduced and made too small, the introduction side portion 44 exceeds the nonmagnetic conductive heat-resistant material upper limit temperature C and is undesirably overheated. Sometimes. At an appropriate flow rate, the temperature distribution of the tube body 43 was close to a straight line (see the broken line), but when the flow rate was reduced, the temperature suppression capability for the introduction side portion 44 of the tube body 43 was weakened, and the temperature distribution of the tube body 43 increased. It becomes a convex bow (see solid line). Therefore, the maximum temperature generated in the connecting portion of the introduction side portion 44 to the discharge side portion 45 rises with a decrease in the flow rate, and exceeds the nonmagnetic conductive heat resistant material upper limit temperature C at a minute flow rate outside the appropriate range. It also becomes.

  About the Example 3 of the high temperature fluid heating apparatus of this invention, the specific structure is demonstrated with reference to drawings. 4A is a longitudinal sectional front view of the main part of the high-temperature fluid heating apparatus 50 with the heat insulating material and the support legs removed, FIG. 4B is a block diagram of the control circuit, and FIG. 4C is the heat insulating material and the support legs. It is a longitudinal front view of the principal part of the high-temperature fluid heating apparatus 50 which removed etc., (a) shows the state before coil movement, (c) has shown the state after coil movement.

  This high-temperature fluid heating device 50 is different from the high-temperature fluid heating device 40 of the first embodiment described above in that the length L2 of the introduction side portion 44 of the dissimilar material connecting tube body 43 is slightly longer than the length L1 of the induction coil 17. The point which becomes long, the point where the moving mechanism 54 which moves the coil holding | maintenance part 54a holding the induction coil 17 fixed length about the distance L4 in the axial direction was additionally equipped, and the dissimilar material connection pipe body 43 In order to detect the temperature of the discharge side portion 45 near the introduction side portion 44, for example, a magnetic refractory material portion thermometer 52 made of a thermocouple is attached to the discharge side portion 45, and detection of this thermometer 52 A movement control circuit 53 for controlling the operation of the movement mechanism 54 based on the temperature is provided. In the figure, a thermometer 52 is erected for easy visual recognition, but the thermometer 52 and its wiring are close to a heat insulating material (not shown) so as not to hinder the movement of the induction coil 17.

  The length L3 of the discharge side portion 45 of the dissimilar material connecting tube body 43 (see FIG. 4A) is shorter than the length L2 of the introduction side portion 44 and further shorter than the length L1 of the induction coil 17. Further, the movable distance L4 of the induction coil 17 is obtained by subtracting the length L1 of the induction coil 17 from the total length L2 + L3 of the dissimilar material connecting tube body 43 that is obtained by combining the length L2 of the introduction side portion 44 and the length L3 of the discharge side portion 45. Is equal to or slightly shorter than the length.

  The moving mechanism 54 is composed of a linear motion mechanism such as a motor-driven ball screw mechanism or an air-driven cylinder mechanism, and the movement control circuit 53 (see FIG. 4B) is based on the temperature detected by the thermometer 52. For example, an electronic circuit such as a comparator that performs positioning in an alternative manner, and an electric circuit such as a motor driver or a valve drive relay that controls the drive source of the moving mechanism 54 to move the coil holding portion 54a to a predetermined position. Become.

  Specifically, referring to a threshold temperature E preset to an intermediate value between the Curie temperature A of the discharge side portion 45 and the nonmagnetic conductive heat-resistant material upper limit temperature C of the introduction side portion 44 (see FIG. 4 (b)), when the temperature detected by the magnetic heat-resistant material portion thermometer 52 is below or below the threshold temperature E, the induction coil 17 is directed toward the introduction side portion 44 of the dissimilar material connecting tube 43. The induction coil 17 is removed from the discharge side portion 45 when it is fully filled (see FIG. 4A). Further, when the temperature detected by the magnetic heat resistant material thermometer 52 exceeds or exceeds the threshold temperature E, the induction coil 17 is brought close to the discharge side portion 45 of the dissimilar material connecting pipe body 43 to induce the induction coil 17. The discharge-side portion 45 is surrounded by (see FIG. 4C).

  The use mode and operation of the high-temperature fluid heating apparatus 50 of Example 3 will be described with reference to the drawings. FIG. 5 shows the operation characteristics, (a) is a temperature rise characteristic graph in which elapsed time is taken on the horizontal axis and temperature is taken on the vertical axis, and (b) to (d) are all dissimilar material connecting pipes on the horizontal axis. 43 is a temperature distribution graph in which the position on 43 is taken and the temperature is plotted on the vertical axis, (b) is the temperature distribution before moving the coil, (c) is the temperature distribution after moving the coil, and (d) is also the effect of the flow rate. It is the temperature distribution after coil movement. Here, the temperature rise characteristics will be mainly described.

  When energization and fluid supply are started at time T0, electromagnetic induction heating is performed. Until the temperature detected by the thermometer 52 reaches the threshold temperature E, the induction coil 17 is connected to the introduction-side portion 44 of the dissimilar material connecting pipe body 43. Since it is only applied to the non-magnetic conductive heat-resistant material, and the induction coil 17 conforms to the electromagnetic induction conditions over the entire length in this state, the introduction side portion 44 quickly rises in temperature and the heat is directly conducted or fluidized. It is also carried to the discharge side portion 45 by intervening transmission, and the discharge side portion 45 also rises in temperature. The heating rate (see the solid line graph in FIG. 5A) is the case of the high-temperature fluid heating device 50 in which the induction coil 17 is also applied to the discharge side portion 45 (see the two-dot chain line graph in the figure). Faster than the case where the entire length of the tubular body is made of a non-magnetic conductive heat-resistant material (see the one-dot chain line graph in the figure). In addition, the temperature control capability is improved as much as the heating rate is increased.

  Then, when the detected temperature of the thermometer 52 reaches the threshold temperature E and exceeds the threshold temperature E, the induction coil 17 moves from the introduction side portion 44 of the dissimilar material connecting tube 43 to the discharge side portion 45, but the threshold temperature E is changed to the discharge side portion. 45 is set higher than the Curie temperature A of the magnetic conductive heat-resistant material, and the discharge side portion 45 is compatible with the induction coil 17 and the electromagnetic induction conditions, so that a rapid temperature rise rate is maintained. Warm time is further reduced. Therefore, the arrival time T7 of the high-temperature fluid heating device 60 to the control target temperature D is further shortened from the arrival time T6 of the high-temperature fluid heating device 50 to the control target temperature D, and approaches the conventional virtual time T2 (= T1). X (1.1-1.3)). As described above, since the temperature rising rate is maintained in a rapid state from the low temperature range to the high temperature range, the temperature control capability is also good in the entire temperature range.

  Further, when looking at the temperature distribution in the dissimilar material connecting tube 43, only the introduction side portion 44 generates heat until the temperature detected by the thermometer 52 reaches the threshold temperature E (see FIG. 5B). Among them, the connecting portion with the discharge side portion 45 becomes the highest temperature, but the threshold temperature E is never exceeded. Then (see FIG. 5 (c)), when the maximum temperature exceeds the threshold temperature E, the induction coil 17 is moved toward the discharge side portion 45 of the dissimilar material connecting tube body 43. Since the temperature rise is suppressed, even if the temperature of the discharge section 16 reaches the high control target temperature D, the temperature of the introduction side portion 44 of the dissimilar material connecting pipe body 43 does not exceed the nonmagnetic conductive heat resistant material upper limit temperature C. . Since the temperature rise suppression of the introduction side portion 44 is effective even at a small flow rate (see FIG. 5D), even if the flow rate of the fluid to be heated is reduced to a minute flow rate outside the appropriate range, the dissimilar material connecting tube 43 Rarely exceeds the upper limit temperature C of the nonmagnetic conductive heat-resistant material.

  About the Example 4 of the high temperature fluid heating apparatus of this invention, the specific structure is demonstrated with reference to drawing. FIG. 6 shows another configuration example of the movement control circuit 53 of the high-temperature fluid heating device 50 described above, and (a) to (b) all take the temperature of the nonmagnetic heat-resistant material part 44 on the horizontal axis and guide on the vertical axis. It is the control characteristic graph which took the position of the coil 51, (a) is a simple hysteresis characteristic, (b) is the case of the characteristic which combined the hysteresis with proportional control.

  For example, a hysteresis comparator is used as the comparator of the movement control circuit 53, and the threshold temperature E is expanded to a lower threshold temperature E1 and a higher threshold temperature E2 (see FIG. 6A), and a magnetic heat resistant material thermometer. When the detected temperature of 52 exceeds the threshold temperature E2, the induction coil 17 approaches the discharge side portion 45, and when the detected temperature of the non-thermometer 52 falls below the threshold temperature E1, the induction coil 17 becomes the introduction side portion 44. By moving closer to this direction, it is possible to easily avoid the excessive movement of the hunting-like induction coil 17 that may occur due to minute temperature fluctuations, noise, or the like.

  Further, instead of the hysteresis comparator described above (see FIG. 6B), for example, by using an operational amplifier having hysteresis, the induction coil 17 can be stopped at the intermediate position according to the temperature detected by the thermometer 52. By doing so, it is possible to move the induction coil 17 quickly when it is necessary to respond promptly while the movement of the induction coil 17 is moderated.

  A specific configuration of the high-temperature fluid heating apparatus according to the fifth embodiment of the present invention will be described with reference to the drawings. FIGS. 7A to 7C are vertical front views of essential parts of the high-temperature fluid heating device 60 with the heat insulating material and support legs removed, where FIG. 7A is a state before moving the coil, and FIG. Is the state during coil movement, and (c) is the state after coil movement.

This high-temperature fluid heating device 60 is different from the high-temperature fluid heating device 50 of the third embodiment described above in that the moving mechanism 54 that moves the induction coil 17 while keeping its length fixed expands and contracts the induction coil 17 to move. This is a mechanism 61.
In this case, since both ends of the induction coil 17 can be individually positioned and moved within a range in which the induction coil 17 is not damaged, the degree of freedom in design and adjustment is increased.

[Others]
In the above embodiment, the PID calculation is given as an example of feedback control calculation. However, depending on the application, PI calculation or P calculation may be used.

  The high-temperature fluid heating device of the present invention can be applied to a superheated steam generator for further heating saturated steam, reforming pyrolysis gas such as woody biomass, decomposition of toxic gas such as dioxin, heating of various gases, low melting point It can also be applied to heating of materials.

10 ... Superheated steam generator (high temperature fluid heating device),
DESCRIPTION OF SYMBOLS 11 ... Introduction part, 12 ... Heating part, 13 ... Tube (heating element),
16 ... discharge part, 17 ... induction coil, 21 ... heating element thermometer,
22 ... Discharge steam thermometer, 23 ... Temperature control circuit, 24 ... High frequency power supply,
25 ... Saturated steam generator, 26 ... Superheated steam treatment device,
30 ... Superheated steam generator, 31 ... Induction coil,
40 ... High temperature fluid heating device,
42 ... heating unit, 43 ... dissimilar material connecting pipe (heating element),
44 ... Introduction side part (non-magnetic heat resistant material), 45 ... Discharge side part (magnetic heat resistant material),
47 ... High temperature fluid heating device, 48 ... High temperature fluid heating device, 49 ... Induction coil,
50 ... High temperature fluid heating device,
52... Magnetic refractory material thermometer, 53 ... Movement control circuit,
54 ... Moving mechanism, 54a ... Coil holding part,
60 ... High-temperature fluid heating device, 61 ... Extension mechanism

Claims (5)

  An introduction part for introducing a fluid to be heated, a discharge part for discharging the heated fluid, a pipe serving as a heating element in which one end is connected to the introduction part and the other end is connected to the discharge part, and a hollow forms a flow path In a high-temperature fluid heating apparatus comprising a body and an induction coil that is disposed around an outer periphery of the tube and that inductively heats the tube when energized, an introduction-side portion connected to the introduction portion of the tube Is made of a non-magnetic conductive heat-resistant material, a discharge side portion of the tubular body connected to the discharge portion is made of a magnetic conductive heat-resistant material, and an upper limit temperature of the non-magnetic conductive heat-resistant material is the magnetic conductive heat-resistant material. A high-temperature fluid heating apparatus characterized by being higher than the Curie temperature.   2. The high-temperature fluid heating apparatus according to claim 1, wherein the induction coil is fixed so as to surround the introduction side portion of the tubular body and the discharge side portion of the tubular body.   A moving mechanism for moving the induction coil in the axial direction and a thermometer for detecting the temperature of the discharge side portion of the tubular body are provided, and when the detected temperature is lower than the Curie temperature of the magnetic conductive heat-resistant material, When the detection temperature is higher than the Curie temperature of the magnetic conductive heat-resistant material, the induction coil is moved to the introduction-side portion of the tubular body by the moving mechanism and removed from the discharge-side portion. The induction coil is moved toward the discharge side portion of the tubular body by the moving mechanism while the temperature is lower than the upper limit temperature, and the discharge coil is surrounded by the induction coil. The high-temperature fluid heating apparatus according to claim 1.   4. The high-temperature fluid heating apparatus according to claim 3, wherein the moving mechanism moves the induction coil with a fixed length.   The high-temperature fluid heating apparatus according to claim 3, wherein the moving mechanism moves the induction coil by expanding and contracting.

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