JPH07233901A - Steam generating device - Google Patents

Abstract

PURPOSE:To provide a steam generating device for a turbin and the like wherein a sufficient high temperature condition is economically achieved in the inside of a furnace, with a high thermal efficiency, and besides, the temperature can be stably sustained. CONSTITUTION:In a steam generating device having a furnace wherein a fire flame is introduced from a fire opening and an inside of the furnace body is given a high temperature condition, an inner wall material 14 of a furnace body is composed of a refractory material of ceramics and a heat insulation space 13 is formed between an outside wall material 12 composing an outside section of the furnace body and the inside wall material 14. By this device, a low pressurization of the heat insulation towards a vacuum side is executed, and besides, a heat exchange structure for generating steam is arranged, in a furnace body, and the heat exchange structure has a heat exchange section 5 composed of a refractory wall 17 exposed in the inside of the furnace, in which at least its outside is of a ceramic material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a steam generator for generating high temperature steam to be supplied to a steam turbine or the like.

[0002]

2. Description of the Related Art This type of steam generator (boiler) is
Basically, a heat exchange pipe line group (heat exchange section) is provided between the water supply tank and the steam tank, and the space through which the pipe line group passes is configured as a furnace. Therefore, the inner wall of the furnace is generally made of refractory brick or the like, and combustion is performed in the furnace by a gas burner or the like. Here, in order to improve the heat exchange efficiency, it is necessary to maintain high heat conductivity of the pipe wall, and heat transfer fins etc. are equipped, but these are made of metal and are not sufficient in terms of heat resistance. Is. For this reason, a refractory material is attached to the outer surface of the heat exchange section exposed in the furnace by means such as spray coating, but the temperature inside the furnace still has considerable restrictions.

On the other hand, since it is necessary to keep the temperature inside the furnace high and stable, sufficient heat insulation from the outside must be ensured. Therefore, the furnace wall is thickened so that a sufficient thermal gradient can be maintained, so that the structure becomes quite large. Moreover, since the heat capacity of the furnace wall is large and the amount of heat released from the outer surface of the furnace wall is large, the temperature inside the furnace is raised, and a considerable energy cost is required to maintain the high temperature.

[0004]

Therefore, regarding the furnace wall, the present inventor has in the past made at least the furnace wall forming the outer circumference and the inner circumference of the furnace into a double structure having a low pressure void in the middle. Proposed a furnace. As a result, the heat insulating property is dramatically improved, and the desired furnace temperature can be economically secured. Here, a lightweight refractory material formed by molding ceramic fibers into the required shape and thickness by means such as compression molding,
It constitutes the inner wall member of the furnace body. The inner wall member has excellent heat insulating properties due to the characteristics of its material and has a small heat capacity, so that it is possible to efficiently raise the temperature inside the furnace. Moreover, since the pressure between the outer wall member and the outer wall member is reduced to the vacuum side, it is possible to secure a sufficient heat insulation property than expected.

Therefore, the present inventor has conceived of constructing a furnace of a steam generator using such a furnace body. In this case, the heat exchange efficiency of the heat exchange section and the heat resistance are improved so that combustion can be performed at a sufficiently high temperature.

[0006]

That is, the object of the present invention is to economically achieve a sufficiently high temperature condition in a furnace with high thermal efficiency.
Another object of the present invention is to provide a steam generator for a turbine or the like, which can maintain its temperature stably.

[0007]

Therefore, in the present invention,
In a steam generator having a furnace for introducing a flame from a crater to bring the furnace body to a high temperature state, a refractory material made of ceramic constitutes an inner wall member of the furnace body, and an outer wall member constitutes an outer portion of the furnace body. And between the inner wall member and a heat insulating gap, while reducing the pressure of the heat insulating gap to the vacuum side,
The furnace body is provided with a heat exchange structure for generating steam, and the heat exchange structure has a heat exchange section exposed in the furnace body, at least the outside of which is constituted by a fireproof wall made of a ceramic material. It is characterized by having.

In this case, a preliminary heat exchange section communicating with the heat exchange section may be provided inside the outer wall member, on the outer side thereof, or on the side of the heat insulating void. Further, at least the refractory wall covering the inner wall member and the heat exchange portion, using a lightweight refractory material molded ceramic fiber, to increase the density of the refractory material inside the outer wall member and the heat exchange portion, It is advisable to impregnate or apply a ceramic refractory hardener therein and to configure the inner side surface of the outer wall member as a radiant heat reflecting surface.

[0009]

As a result, in the furnace surrounded by the inner wall member, a high temperature state can be obtained with sufficient heat insulation, and the high temperature state can be stably maintained. Further, since the exposed portion in the furnace of the heat exchange portion is protected by a fireproof wall such as a lightweight fireproof material formed by molding ceramic fibers, it is possible to exhibit fire resistance sufficiently against high temperature. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the steam generator of the present invention will be specifically described below with reference to the drawings. The steam generator is a water source (not shown) via the pressure pump 1.
The water supplied from is supplied to the water supply tank 2A via the pipe line 2 and, via the tick valve 3, to the preliminary heat exchange section 4 of the heat exchange structure, and further to the cylindrical metal heat exchange section 5. Supplied under pressure. Then, it is preheated in the preliminary heat exchange section 4, is vaporized in the heat exchange section 5, and is supplied to, for example, the steam turbine 7 via the pipe line 6. Such a route itself is the same as the conventional steam generator, and if necessary, various known facilities (not shown) such as the conventional ones may be attached to the route.

As shown in FIGS. 1 and 2, the furnace of the present invention having the above-mentioned heat exchange structure installed therein has a furnace base 8 having burner insertion portions 8A on four sides, and a burner nozzle on the furnace base 8. Crater member 1 installed to hold 9
0 and a flame introduction port 11A communicating with the inside of the crater member and installed on the crater member 10
And the outer periphery of the furnace body are assembled / configured on the hearth member 11, for example, a substantially cylindrical outer wall member 12, and a furnace with a required (for example, about 20 mm) heat insulating gap 13 formed in the outer wall member 12. For example, a substantially cylindrical inner wall member 14 that is installed on the hearth member 11 so as to assemble and configure the inner circumference of the body, a chimney member 15 that forms an exhaust hole 15A around the upper end, and a canopy that closes the upper end Furnace lid member 16 and the heat exchange section 5
The heat-resistant wall 17 made of a ceramic material that covers the exposed surface of the inside of the furnace in a contact state.

At least the inner wall member 14 and the fireproof wall 17 are made of thin lightweight fireproof material formed by molding ceramic fibers by, for example, compression molding. The lightweight refractory material is preferably 15 mm to 35 m.
m, for example, has a thickness of about 25 mm. Also,
In this embodiment, for convenience of transportation and other handling, almost all the constituent members are made of lightweight refractory material which is the same material as the inner wall member.

Further, in this embodiment, an exhaust hole 15B is provided around the base of the chimney member 15 formed above the furnace body, and the heat insulating void 13 is provided through the exhaust hole 15B to the exhaust passage 15C inside the chimney. The air in the adiabatic space is leaked into the furnace body due to the exhaust effect from the furnace body, and the air density in the adiabatic space is reduced to the vacuum side.

In this case, according to the present invention, the flame outlet diameter (passage cross-sectional area) of the burner nozzle 9 in the furnace crater,
The ratio with the primary air inlet diameter (passage cross-sectional area) to the burner 9 is approximately 25: 4 to 16: 1, preferably
The structural setting is made so that it becomes 9: 1. Further, if necessary, the ratio of the flame outlet diameter (passage cross-sectional area) of the burner nozzle 9 to the secondary air inlet diameter (passage cross-sectional area) from the periphery thereof is approximately 1: 1 to 2: 3. Preferably, the structural setting is made so as to be 4: 5.

Also, if necessary, the passage cross-sectional area of the exhaust passage 15C from the furnace body may be set to the flame outlet diameter of the burner nozzle 9 (in this embodiment, since it is a plurality of nozzles, the total passage cross-sectional area) is 1. The structural setting is made within 5 times, preferably 1.3 times. Further, the furnace height for setting the furnace volume is set to an increased or decreased value corresponding to the increase or decrease of the flame ejection pressure of the burner nozzle 9 (injection pressure of the heat source). With respect to the cross-sectional area in the furnace for setting the flame outlet diameter of the burner nozzle 9 (in this embodiment, since there are a plurality of nozzles, the total cross-sectional area of passage)
Is set to about 1/6 or less, preferably 1/7.

In the furnace of the present invention, the ceramic refractory hardener 1 is added to the outside of the inner wall member 14 and the inside of the refractory wall 17 (that is, the heat exchange section 5 side) so as to increase the density.
8 are provided. In this case, the ceramic-based refractory hardener that is impregnated or applied to the outer side of the inner wall member 14 and the inner side of the refractory wall 17 is, for example, silica, alumina, iron oxide or the like which is usually used as a high temperature heat resistant material. The main raw material is ceramics having the above composition, and others such as coating cement. In addition, in order to improve the heat insulating property when the inner wall member 14 becomes incandescent, the inside of the outer wall member 12 is similarly configured as a radiant heat reflecting surface 12A such as a white surface or a mirror surface of a ceramic refractory material.

Also, in this embodiment, the preliminary heat exchange section 4 is used.
Is constituted by a spiral pipe line buried in the outer wall member 12 (although it may be arranged outside the outer wall member 12 or on the side of the heat insulating void 13). Further, the furnace lid member 16
Are vertically positioned so that the opening cross-sectional area (total passage cross-sectional area) of the exhaust hole 15A can be adjusted, and as a result, the passage cross-sectional area of the exhaust passage 15C can be substantially adjusted and controlled. It is preferable that the structure is adjustable.

Therefore, the heat insulation structure of the furnace body, the reflection of radiant heat,
In addition, under the above-mentioned conditions, a complete combustion state is obtained in the furnace surrounded by the inner wall member 5, and the temperature in the furnace is raised to the required temperature (for example, 1,000 ° C. or higher). And, if necessary, for temperature stability, at or near this point,
For example, the reduction rate (throttle) of the fuel supply amount to the burner nozzle 9 and the reduction rate (throttle) of the passage cross-section of the exhaust passage 15C are made substantially the same so that the furnace temperature is maintained at a predetermined temperature. Can be controlled.

That is, the cock 19 for supplying the fuel gas to the burner nozzle 9 is throttled to, for example, 30 when the fuel is fully opened.
% While controlling the supply amount to about 10%, and adjusting the exhaust gas as described above (here, the same amount as the throttle of the cock 19, for example, 3
The reduction of the cross-section area of 0%) reduces the reactive loss of thermal energy. Therefore, while exhibiting sufficient heat insulating properties by the heat insulating voids, the temperature can be rapidly raised, and a required high temperature state can be stably maintained. In this embodiment, the temperature inside the furnace is stabilized at, for example, about 1,250 ° C., but if necessary, the amount of fuel supplied to the burner nozzle 9 may be adjusted at or near the required temperature. The reduction rate (throttle) of the passage cross section of the exhaust passage 15C is made smaller than the reduction rate (throttle) so that the temperature inside the furnace is gradually increased even after the temperature control is started, or the burner nozzle 9 is used. Reduction rate of fuel supply (throttle)
Even if the reduction rate (throttle) of the cross-sectional area of the exhaust passage 15C is reduced, the temperature control is started, and thereafter both reduction rates are gradually reduced to increase the temperature in the furnace. Good. That is, as an example thereof, the cock 19 for the burner nozzle 9 is throttled to, for example, about 50% of the fully opened state, and the passage cross-sectional area of the exhaust passage 15C is set to, for example, the cock 1.
The throttling ratio of 9 is about ⅔ to ⅔, that is, about 25% in this case, or the reduction amount is suppressed, or thereafter, the throttle of the cock 19 and the passage cross-sectional area of the exhaust passage 15C are reduced. By controlling the amount to be gradually returned, a further temperature rise (for example, 1,520 ° C. or higher) may be promoted within a range in which the furnace body is not burned while obtaining economical efficiency of thermal energy.

In the above embodiment, in order to promote the steam generation in the heat exchange section 5, the end of the path from the preliminary heat exchange section 4 is communicated with the introduction nozzle 5A protruding into the heat exchange section 5. Therefore, the introduction nozzle 5A has a large number of injection holes on its peripheral surface, and ejects hot water toward the inner wall of the heat exchange section 5. In this case, the metal wall of the heat exchange section 5 is in a considerably high temperature state, but since it is in contact with the inner surface of the heat resistant wall 17, the mutual mutual action ensures mechanical strength and withstands steam pressure. be able to.

Further, since the pressure of the heat insulating void 13 is reduced to the vacuum side, the heat insulating property is remarkably improved. Therefore, even if the inner wall member 14 becomes incandescent at the temperature inside the furnace, the inner surface (radiation heat reflecting surface) of the outer wall member 12 does not substantially exceed 800 ° C., so that the refractory material on the surface becomes red heat. Since the white surface is maintained without doing so, the reflection efficiency of the radiant heat can be maintained at a high value, and the heat insulation of the furnace can be improved more and more. Also,
In this embodiment, due to the ejector effect of the exhaust flow in the exhaust hole 15B, the pressure reduction of the heat insulating void 13 can be sufficiently achieved without using any special auxiliary equipment. In addition, according to the experimental experience of the inventor, in order to maintain the ejector effect, the passing cross-sectional area of the space connecting the heat insulating space 13 and the exhaust hole 15B is:
It is necessary that the cross sectional area of the exhaust passage 15C is one third or less.

Although not provided in this embodiment, the temperature inside the furnace is measured by a temperature sensor, and the fuel supply amount to the burner nozzle 9 and the exhaust passage 15C passage cross section are controlled based on the measured values. It is good to have a configuration that does.

[0023]

As described above in detail, the present invention provides a steam generator having a furnace for introducing a flame from the crater to bring the inside of the furnace to a high temperature state. Of the inner wall member, between the outer wall member and the inner wall member constituting the outer portion of the furnace body, while forming a heat insulating void, the heat insulating void is reduced in pressure to the vacuum side, and the furnace body , A heat exchange structure for generating steam is provided, and the heat exchange structure has a heat exchange portion exposed in the furnace body and at least the outside of which is constituted by a fire wall of a ceramic material, so that high heat efficiency is achieved. In the above, the effect of economically achieving a sufficiently high temperature state in the furnace and maintaining the temperature stably can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

FIG. 2 is a first transverse sectional view of the above embodiment.

FIG. 3 is a second transverse side view of the above embodiment.

[Explanation of symbols]

 1 Pumping Pump 2 Pipe 2A Water Tank 3 Check Valve 4 Preliminary Heat Exchange Section 5 Heat Exchange Section 6 Pipe Line 7 Steam Turbine 8 Furnace Base 9 Burner Nozzle 10 Crater Member 10A Burner Nozzle Inlet 11 Hearth Member 11A Flame Inlet 12 Outer Wall Member 12A Radiant heat reflecting surface 13 Void 14 Inner wall member 15 Chimney member 15A, 15B Exhaust hole 15C Exhaust passage 16 Furnace lid member 17 Heat-resistant wall 18 Fire-resistant hardener 19 Cock

Claims (3)

[Claims] 1. In a steam generator having a furnace for introducing a flame from a crater to bring the inside of the furnace to a high temperature state, a refractory material made of ceramic constitutes an inner wall member of the furnace body, and an outer portion of the furnace body. Between the outer wall member and the inner wall member constituting the,
In addition to forming an adiabatic void, lowering the adiabatic void to the vacuum side, the furnace body is provided with a heat exchange structure for steam generation, and the heat exchange structure is exposed in the furnace body. At least the outer side of the steam generator has a heat exchange section formed of a fireproof wall made of a ceramic material. 2. The inside or outside of the outer wall member, or
The steam generator according to claim 1, further comprising a preliminary heat exchange section that is connected to the heat exchange section and that is in communication with the heat exchange section. 3. A lightweight refractory material formed of ceramic fiber is used for at least the fire wall covering the inner wall member and the heat exchange section, and the density of the inside of the fire wall covering the outer side of the inner wall member and the heat exchange section is increased. 3. The steam generator according to claim 1 or 2, wherein the ceramic-based refractory hardener is impregnated or applied thereto, and the inner surface of the outer wall member is formed as a radiation heat reflecting surface.