JPH06241436A - Method and apparatus for heating tube type heating furnace - Google Patents

Abstract

PURPOSE:To improve a thermal efficiency and to reduce public pollution by passing combustion oxidizer to be discharged from an oxidizer supply passage through a heat accumulator provided on a wall of a combustion chamber and agingly changing an oxidizer passing area of the accumulator in a heating furnace in which exhaust gas is used to heat the oxidizer. CONSTITUTION:A combustion apparatus 30 has a burner 31, a heat accumulator 32 as a heat exchanging member mounted on a hearth 12 for forming a wall of a combustion chamber, and a duct 33. A duct 33 formed with an oxidizer supply passage 36 for supplying the oxidizer to the burner 31 and an exhaust gas discharge passage 37 for externally discharging burned exhaust gas communicates with an opposite combustion chamber side of the accumulator 32. The passage 36 is so formed as to discharge the oxidizer from a plurality of outlets toward the accumulator 32 in such a manner that an area for passing the oxidizer through the accumulator 32 is agingly changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating method and apparatus for a tubular heating furnace in which the heat of exhaust gas after combustion is used for heating an oxidizing agent such as combustion air.

[0002]

2. Description of the Related Art A tube-type heating furnace is used in various processes including petroleum refining, petrochemicals, and general chemistry, and heats a heated fluid flowing in the tube with an open flame.

As shown in FIG. 8, in a conventional tube-type heating furnace, a heating pipe 101 is arranged in a combustion chamber 100 in which a steel plate casing is lined with a refractory heat insulating material, and a combustion device 102 is provided. And the combustion device 102
In this way, a fluid to be heated such as naphtha or gasoline flowing in the heating pipe 101 is heated.

Conventionally, this tube type heating furnace is often heated by utilizing radiation and convection of flame, and a portion mainly heated by radiation heat transfer is a radiation portion 103, and a portion mainly heated by convection heat transfer. Is used as the convection section 104, and the flow of the fluid to be heated is of the countercurrent type with the flow of the normal combustion gas from the viewpoint of improving thermal efficiency. Each heating pipe 101 is connected in series by a U-shaped joint to form a so-called coil path, and the fluid to be heated first flows into the convection section 104 from the inlet tube 106 and then enters the radiation section 103 after being preheated. When heated to a predetermined temperature, it flows out from the outlet pipe 107. In FIG. 8, reference numeral “105” is a chimney.

The thermal efficiency of such a tubular heating furnace is as follows.
Normally, it is 60 to 85%, but even in a large-sized tubular heating furnace as shown in FIG. 9 (the same members as the members shown in FIG. 8 are given the same reference numerals), the preheating by the convection section 104 is not possible. It is difficult to obtain 90% thermal efficiency due to the restriction of the fluid inlet temperature. Therefore, the pipe heating furnace may be provided with a preheater 108 for preheating an oxidizer composed of combustion air or the like and a waste heat boiler to increase the thermal efficiency to 90% or more.

As used herein, the term "oxidizer" generally means pure oxygen,
It is a general term for molecular oxygen such as air and oxygen-enriched air. However, in special cases, an oxidizing element or compound such as halogen or nitric oxide may be used as the oxidizing agent.

In FIG. 9, reference numeral "109" is a forced air blower, and "110" is an induced air blower.

[0008]

However, in such a tube-type heating furnace, the heat transfer area of the convection section 104 is equal to the radiation section 103.
Although the heat absorption amount is less than half that of the radiant part 103, the convection part 104 should be eliminated and only the radiant part 103 should be used in the small heating furnace, in spite of more than double As a result, preheating may be insufficient and a tubular heating furnace with low thermal efficiency may be obtained.

[0009] In addition, although a tubular heating furnace requires a large amount of absorbed heat as the entire furnace like a heating furnace for a catalytic reformer, for example, due to process requirements, an inlet fluid of a fluid to be heated is required. The temperature is high (around 440 ℃) and the permissible pressure loss in the pipe is extremely small (0.2 to 0.3 kg /
cm ² ) May need to be set. In this case, the same fluid to be heated as the radiation unit 103 cannot flow in the convection unit 104 and must be heated only by the radiation unit 103. Therefore, the achievable thermal efficiency is naturally limited and the performance is improved. There is a problem that you cannot do it.

Further, the large tubular heating furnace shown in FIG.
Since the oxidizer preheater 108, the waste heat boiler, and the like are additionally provided, the length L ₁ in the lateral direction is aside from the length L ₁ in the longitudinal direction of the furnace.
₂ becomes large, a large site is required, and the oxidizer preheater 108 and the like require a construction cost equivalent to that of the furnace main body, resulting in an increase in the cost of the entire apparatus.

The present invention has been made in order to solve the problems associated with the prior art described above, and a first object thereof is to provide an inlet fluid temperature when a fluid to be heated flows into a heating device of a tubular heating furnace. Another object of the present invention is to provide a heating method for a tubular heating furnace, which has high thermal efficiency and low pollution without being restricted by the allowable pressure loss value in the tube, and has little fluctuation in pressure in the furnace.

The second object is to have high thermal efficiency and low pollution without being restricted by the temperature of the inlet fluid or the allowable pressure loss value in the pipe when the fluid to be heated flows into the heating device of the tubular heating furnace. However, it is another object of the present invention to provide a compact and inexpensive heating device for a tubular heating furnace in which the fluctuation of the pressure inside the furnace is small.

[0013]

The present invention which achieves the first object is to provide a combustion apparatus in which a large number of heating pipes through which a fluid to be heated flows are arranged in the combustion chamber and a flame is injected into the combustion chamber. In the heating method of the tubular heating furnace, wherein the heating fluid inside is heated by the heat of this flame through the heating tube, in the combustion device, the oxidant is supplied from an oxidant supply passage through which the oxidant flows. The discharged oxidant,
It is characterized in that a part of the heat storage body provided on the wall of the combustion chamber is allowed to pass through and the oxidant passing region of the heat storage body is changed with time.

According to the present invention which achieves the second object, a large number of heating pipes through which a fluid to be heated flows are arranged inside a combustion chamber, and a combustion device for injecting a flame is provided in the combustion chamber. In the heating device of the tube-type heating furnace configured to heat the fluid to be heated inside via the heating pipe, the combustion device includes a burner for heating the heating pipe and an oxidizing agent for supplying an oxidant to the burner. It has an agent supply passage, an exhaust gas discharge passage for discharging exhaust gas after combustion to the outside of the combustion chamber, and a heat storage body for heating the oxidizer by sensible heat of the exhaust gas, and the heat storage body is breathable. It is configured by a heat storage body, and allows the oxidant discharged from the oxidant supply passage to pass through a part of the heat storage body and to change the oxidant passing region of the heat storage body with time. .

[0015]

In the incinerator according to the present invention, there is no convection part and there is only a radiant part, so that it becomes a heating device for a tubular heating furnace.
All the heat from the flame of the burner is absorbed by the radiant section and the heat storage body, the total length of the heating tube can be shortened, and the allowable pressure loss inside the tube can be reduced. Therefore, it is possible to perform predetermined heating without being restricted by the fluid inlet temperature or the allowable pressure loss value in the pipe due to process requirements.

Further, when the exhaust gas is discharged to the outside of the combustion chamber, it is discharged through the relatively rotating heat storage body and the duct portion, so most of the heat of the exhaust gas is used for heating the combustion oxidant. Then, the exhaust gas becomes a low temperature and is discharged out of the system. Moreover, since it is a combustion device in which the oxidizer preheater and the burner are integrated, there is no heat dissipation in the duct portion, and the thermal efficiency is structurally improved.

Further, since the exhaust gas is discharged through the duct portion that rotates relatively to the heat storage body, most of the heat of the exhaust gas is generated by the combustion oxidant due to the heat exchange action of the heat storage portion. It is used for heating, the temperature of the exhaust gas is constant over time, and it is discharged outside the system at a low temperature. Moreover, since the combustion is continuously performed, fluctuations in the pressure inside the furnace due to the combustion are reduced to a negligible level. Further, since the exhaust gas is sucked into the heat storage body from around the flame when it is discharged to the outside, a so-called exhaust gas internal recirculation action occurs in which the exhaust gas and the flame are mixed, and as a result, the NO _x value is drastically reduced. However, low pollution is exhibited.

In addition, since it is not necessary to attach an oxidizer preheater, a waste heat boiler, etc., the size of the entire furnace is reduced,
A large site is not required, construction costs can be reduced, and it becomes a compact and low-priced tube heating furnace heating device.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic sectional view of a tubular heating furnace according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, FIG. 3 is a sectional view of a combustion apparatus, and FIG. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3, FIG. 5 is a graph showing an experimental result of the combustion apparatus of the present invention, FIG. 6 is a graph showing an experimental result relating to NO _X emission value of the combustion apparatus, and FIG. It is a graph which shows the experimental result regarding the pressure fluctuation in the furnace of the same combustion apparatus.

In FIG. 1, a tube-type heating furnace 10 is a box-type heating furnace used in a catalytic reforming apparatus.
Inside the 0, four combustion chambers H _{1 to} H ₄ (reference numeral H is a general term for H _{1 to} H ₄ ) partitioned by a partition wall 11 having a predetermined height are formed. Each of the combustion chambers H _{1 to} H ₄ has a length L ₁ (see FIG. 2) in the longitudinal direction orthogonal to the plane of the drawing, which is as long as ten and several m, and each of the combustion chambers H _{1 to} H ₄ has a predetermined length in the longitudinal direction. A plurality of inverted U-shaped heating pipes P arranged at intervals are provided, and the plurality of heating pipes P constitute a radiation section. The end portion of each heating pipe P extends through the hearth portion 12 which is a part of the wall of the combustion chamber, is arranged at the bottom of the hearth portion 12, and is an inlet pipe that functions as a header extending in the longitudinal direction. I and outlet pipe O, respectively.
The inlet pipe I supplies a process fluid to each heating pipe P, and the process fluid is supplied via a heat exchanger (not shown). The inlet pipe I and the output pipe O of the adjacent combustion chamber H are not shown. They are connected to each other via piping and a reactor. The inlet pipe I and the outlet pipe O are supported on the base 13.

Directly above the combustion chamber H, a passage 15 is opened in the ceiling wall 14, and the exhaust gas damper 1 is provided in this passage 15.
6 is rotatably provided.

Combustion device 30 provided in the combustion chamber H
As will be described later in detail, the flame is injected into a space S (reference S is a general term for the spaces S _{1 to} S ₄ ) defined by a large number of inverted U-shaped heating pipes P, and the radiant heat of the flame is emitted. Is used to heat the fluid to be heated inside via the heating pipe P. In the figure, only one combustion device 30 is shown for each combustion chamber H. The combustion oxidant for the combustion device 30 is air in the present embodiment, and is supplied by the forced air blower 17 and the oxidant supply pipe 18, and the exhaust gas from the combustion device 30 is
It is discharged by the induction blower 19 and the discharge pipe 20.

As shown in FIG. 3, the combustion device 30 can be called, so to speak, a rotary heat storage type burner.
It is composed of a burner 31 that injects a flame upward, a heat storage body 32 that functions as a heat exchange member that is attached to the hearth section 12 that is the wall of the combustion chamber H, and a duct section 33. .

First, it is preferable that the heat storage body 32 is made of a heat-resistant material having a low pressure loss and a large heat capacity and having air permeability, such as ceramics having a large number of honeycomb-shaped holes. By doing so, even if the exhaust gas falls below the acid dew point temperature when heat is recovered from the exhaust gas, the heat storage body is not corroded at low temperature due to the corrosion resistance of the ceramics itself.

Here, the heat resistant material is appropriately selected depending on the use conditions. In addition to ceramics such as various oxides, nitrides, and carbides, heat resistant and oxidation resistant metal materials such as stainless steel and Hastelloy, ceramics and metal materials, or composite materials of ceramics and high melting point materials can be used. As ceramics, alumina,
Silica, silicon carbide, silicon nitride, sialon or the like may be used, but cordierite and mullite are particularly preferable in the present invention in view of heat resistance strength, workability, heat capacity and the like.

The heat storage body 32 is mounted in an opening 34 formed in the hearth 12 and supported by a fixing ring 35.

An oxidant supply passage 36 for supplying a combustion oxidant to the burner 31 and an exhaust gas after combustion in the combustion chamber H are discharged to the outside of the heat storage body 32 on the side opposite to the combustion chamber. The duct portion 33 in which an exhaust gas discharge passage 37 is formed is provided so as to communicate with the heat storage body 32.

The oxidant supply passage 36 discharges the oxidant toward the heat storage body 32 from one or more outlet portions, and the burner 31 provided at the center of the heat storage body 32 is a normal burner. It is a gas or oil burner, the tip of which faces the combustion chamber H. The oxidant for combustion passes through the oxidant supply passage 36 formed in the duct portion 33 from the oxidant supply pipe 18, passes through the heat storage body 32 provided so as to surround the burner 31, and is ejected from around the burner 31. It is supposed to be done.

Further, the outer edge of the opening 34 is
A plate 38 for supporting the burner 31 is provided, and a flange 40 of the main body case 39 is provided on the plate 38.
Are connected by a bolt 41 via a gasket G, so that the main body case 39 and the heat storage body 32 communicate with each other.

The body case 39 has an oxidant inlet portion 42 into which the combustion oxidant from the oxidant supply pipe 18 is introduced.
And an outlet portion 43 for discharging exhaust gas to the discharge pipe 20.
And a duct part 33 provided between the oxidant inlet 42 and the heat storage body 32, and a drive part 45 for rotating the duct part 33.

A large diameter portion 33a of the duct portion 33 is provided inside the body portion 43a of the outlet portion 43. The large diameter portion 33a is a part of the oxidant supply passage 36, and has a cross section of, for example, an acute-angled fan shape as shown in FIG. The inside of the body portion 43a is divided by one or more oxidant supply passages 36, and the oxidant supply passage 36 and the exhaust gas are exhausted in the circumferential direction around the burner 31 inserted through the main body case 39. The gas discharge passages 37 are alternately arranged at predetermined intervals. At the outlet of the oxidant supply passage 36,
The flow rate of the discharged oxidant may be increased by closing the end plate with a large number of small holes.

The oxidant supply passage 36 and the exhaust gas discharge passage 37 are formed as independent passages in the heat storage body 32. For example, the oxidant supply passage 36 flows from the oxidant inlet portion 42. The incoming oxidant is allowed to flow from the small diameter portion 33b through the duct portion 36 to the heat storage body 32 through the gradually expanding large diameter portion 33a.

Further, the exhaust gas discharge passage 37 is provided with a heat storage body 32.
A cross section of the exhaust gas exhausted from is passed through, for example, an obtuse-angled fan-shaped portion, and is guided to the internal space 43b of the body portion 43a in the outlet portion 43.

The drive portion 45 has an inner end portion of a closing plate 49 provided to close the end portion of the body portion 43a of the outlet portion 43 on the side opposite to the heat storage body, and a right end portion of the small diameter portion 33b of the duct portion 33. A support member 50 provided on the inner surface of the support plate 50 and a bearing J respectively rotatably support the duct portion 33 by a seal member S and a bearing J, and a sprocket 51 and a motor M fixed between the bearings J and J. The drive gear 52 rotated by is connected via a chain 53.

As described above, in this embodiment, the duct portion 33
Is supported by the two bearings J, J in good balance, the duct portion 33 can be rotated at a relatively high speed, and if the rotation speed is increased, the thermal efficiency is improved. As a result of examining the relationship between the rotation speed of the duct portion 33 and the thermal efficiency by an experiment, the result is as shown in FIG.

In the experiment, when LPG was used as the fuel and combustion was performed using the combustion apparatus of this embodiment, the duct portion 33 was used.
Was measured by measuring the temperature of the exhaust gas, the residual oxygen concentration of the exhaust gas, the temperature in the furnace, etc. with respect to the rotation speed of the. The horizontal axis of FIG. 5 represents the rotation speed of the duct portion 33, and the vertical axis represents the temperature.

According to the results of this experiment, if the rotation speed of the duct portion 33 is 1 rpm or less, the temperature of the exhaust gas rises sharply, and if it is 1 rpm or more, the rate of decrease of the exhaust gas temperature decreases. It has been found.

Here, the thermal efficiency can be obtained from the relationship between the amount of heat input and the amount of heat loss of exhaust gas, and is given by the following equation.

Η = (Q−C _p · G · T) · 100 / Q where η: thermal efficiency Q: heat capacity of LPG gas C _p : specific heat of exhaust gas G: amount of exhaust gas T: temperature of exhaust gas The thermal efficiency is obtained by substituting the result obtained by the above experiment into this equation. For example, if the engine is selected to rotate at a relatively high speed of 2 rpm, the corresponding exhaust gas temperature is 250 ° C. Therefore, the thermal efficiency at this time is a value of η = (25000 −0.32 · 26 · 250) × 100/25000 = 91.68 (%), which proves that excellent thermal efficiency exceeding 90% is exhibited.

As described above, excellent thermal efficiency is exhibited when rotating at a relatively high speed, because when the rotational speed of the duct portion 33 is increased, the oxidant discharged from the duct portion 33 causes the heat storage body 32 to increase in temperature. It is considered that the temperature of the inhaled oxidant can be increased and the thermal efficiency can be improved because the exhaust gas is heated without lowering the temperature.

The oxidant inlet portion 42 is formed by connecting a base pipe 54 and a branch pipe 55 in a T shape, one end of the base pipe 54 is closed by a lid 56, and the other end is the duct portion. Three
3 is attached to a support plate 50 provided at the end of the small diameter portion 33b. In addition, the code | symbol "57" in FIG. 3 is a current plate.

Further, a fuel pipe 58 for supplying fuel to the burner 31 is provided along the central axis of the duct portion 33. A pipe 59 for supplying motive air to the burner 31 is provided, and this pipe 59 is provided. The magnitude or sharpness of the flame emitted from the burner 31 is adjusted by adjusting the amount of motive air emitted from the burner 31.

The ratio of motive air to the theoretical air amount is preferably 2 to 15%.

Incidentally, instead of the motive air, the pipe 5 is used.
Steam may be discharged from 9. In this case, as shown in FIG. 6, the NO _X emission value decreases while maintaining the flame stability similar to that when the motive air is released. The ratio of the amount of motive steam to the fuel is the calorific value of the fuel 10,0
It is preferably 0.1 to 0.8 kg per 00 Kcal.

Further, when the degree of fluctuation of the pressure in the furnace with time was examined, it was found that the experimental furnace was in a state where fluctuation in the furnace with one burner was most likely to occur,
As shown in FIG. 7, the fluctuation is slight.

Next, the operation of the embodiment will be described.

First, with the exhaust gas damper 16 activated and the passage 15 at the furnace top closed, the forced draft blower 17 and the induced draft blower 19 are started, and the burner 31 is ignited while rotating the motor M (see FIG. 3). Then, the fuel flow injected from the burner 31 through the fuel pipe 58 is supplemented with oxygen by the combustion oxidant flowing through the oxidant supply passage 36 and the heat storage body 32 to form a flame. The fluid to be heated, which is jetted into the space S defined by the heating pipe P and flows through the heating pipe P, is heated by the radiant heat.

Since the tubular heating furnace 10 used in the catalytic reforming apparatus of this embodiment is constructed so as to have only a radiating part without a convection part, most of the radiant heat of the flame is in the radiant part and the heat storage part. Will be absorbed.

Since the heat flux of the radiant section is generally larger than that of the convection section described above, the total length of the heating pipe P can be made shorter than that of the conventional heating furnace having the convection section.
As a result, the allowable pressure loss in the pipe is reduced by the amount that the overall length can be shortened.

Therefore, even if the inlet fluid temperature of the fluid to be heated is high and the allowable pressure loss inside the pipe must be reduced due to process requirements, as in the case of a tubular heating furnace used in a catalytic reforming apparatus, the radiation can be reduced. Since the temperature of the inlet fluid can be made high due to the heating by the section and the allowable pressure loss in the pipe can be made small as described above, the prescribed heating is performed without being restricted by the fluid inlet temperature or the allowable pressure loss value in the pipe. be able to.

The high-temperature exhaust gas after heating the heating pipe P in the combustion chamber H is discharged to the outside of the combustion chamber H. The exhaust gas passes through the heat storage body 32 and is discharged from the exhaust gas discharge passage 37. To be done. Since the heat storage body 32 is heated to a high temperature by the flow of the exhaust gas, when the combustion oxidant discharged from the rotating oxidant supply passage 36 flows into the heat storage body 32, the combustion oxidizer Is heated by the heat storage body 32. This heating is a so-called immediate heating system in which the oxidant is blown from the oxidant supply passage 36 toward the heat storage body 32 to immediately heat the oxidant for combustion, so that most of the heat of the exhaust gas is burned. Used to heat the oxidizer for
High-temperature combustion oxidizer is efficiently produced without heat loss, the temperature of exhaust gas becomes constant regardless of time, and the exhaust gas becomes low temperature and is discharged out of the system.

Further, since combustion and exhaust gas emission are carried out continuously, fluctuations in the furnace pressure due to combustion are reduced to a negligible level.

In this way, the exhaust gas after burning in the combustion chamber H is discharged to the outside, but in this case, the exhaust gas is sucked into the heat storage body 32 from around the flame, so the exhaust gas Mixes with the flame and a so-called exhaust gas internal recirculation action occurs, resulting in a drastic reduction of the NO _x value and low pollution.

Since the combustion device 30 has the oxidizer preheater and the burner integrated with each other, there is no heat loss due to the connection duct, and the structure contributes to the improvement of the thermal efficiency. Since it is not necessary to attach an oxidizer preheater or a waste heat boiler, the overall size of the furnace is reduced,
It does not require a large site, it becomes a compact heating device for a tube heating furnace, and construction costs can be reduced, which is advantageous in terms of cost.

As a result of quantitative evaluation of the tubular heating furnace of this example and the conventional heating furnace, the results shown in Table 1 below were obtained.

The performance of the tubular heating furnace used here is as follows.

Designed heat absorption; 30 × 10 ⁶ Kcal / H Fluid inlet / outlet temperature; 260/400 ° C. Fuel; Fuel gas thermal efficiency; 90% Heating tube material; Low alloy steel Allowable average heat flux; 27,100 Kcal / m ² H In addition, the conventional tube heating furnace has a convection section for preheating the fluid in addition to the radiating section, and the convection section alone cannot achieve 90% thermal efficiency due to the restriction of the fluid inlet temperature. Therefore, an oxidant preheating system shall be installed.

[0059]

[Table 1]

In the tubular heating furnace of this embodiment, as shown in the section of the heating furnace plan view in this table, the heating furnace body of the present invention is somewhat large. This is because in order to avoid coking of the fluid to be heated, there is an upper limit to the average heat flux or fluid film temperature, and even in the tubular heating furnace of this embodiment, the average heat flux or film temperature is Since the limit value is the same as that of the tube heating furnace, the heat transfer area of the radiating part is increased accordingly, and the site of the heating furnace main body is enlarged.

However, in the tubular heating furnace of this embodiment, since the oxidizer preheater is integrated with the combustion device, both of them are required as compared with the conventional tubular heating furnace including the oxidant system. If the required site area of the present invention is 100, the conventional site will be 200 in the conventional tube heating furnace. this is,
This is remarkably effective when a heating tube is installed only in the radiant section due to the restriction of the allowable pressure loss, as in the case of a tubular heating apparatus for a catalytic reformer. Further, as shown in the approximate construction cost, since the heat transfer area is small, the expensive heating tubes are reduced, and the construction cost is lower than that of the conventional tubular heating furnace.

The present invention is not limited to the above-mentioned embodiments, but can be appropriately modified and used within the scope of the claims.

In the above-mentioned embodiment, the oxidant supply passage side, that is, the duct portion is rotated with respect to the heat storage body, but the present invention is not limited to this, and the heat storage body and the duct portion are relative to each other. As long as it can rotate, the heat storage body may be rotated.

Although a pipe for supplying motive air or motive steam is provided at the center of the rotary duct portion 33, this pipe is not necessarily provided.

Further, the combustion apparatus provided so as to face the combustion chamber is not limited to one row as shown in FIG. 2, but may be a plurality of rows as shown in the section of the plan view of the heating furnace.

[0066]

As described above, according to the present invention, the following effects can be obtained.

The heat from the flame of the burner is as follows because it is a heating device for a tube-type heating furnace that has no convection section but only a radiation section.
All are absorbed in the radiant section and the heat storage body, the total length of the heating tube can be shortened, and the allowable pressure loss inside the tube can be reduced. Therefore, it is possible to perform predetermined heating without being restricted by the fluid inlet temperature or the allowable pressure loss value in the pipe due to process requirements.

When the exhaust gas is discharged to the outside of the combustion chamber, it is discharged through the relatively rotating heat storage body and the duct portion, so most of the heat of the exhaust gas is used for heating the combustion oxidant. Then, the exhaust gas becomes a low temperature and is discharged out of the system. Moreover, since it is a combustion device in which the oxidizer preheater and the burner are integrated, there is no heat dissipation in the duct portion, and the thermal efficiency is structurally improved.

Further, since the exhaust gas is discharged through the duct portion that rotates relatively to the heat storage body, most of the heat of the exhaust gas is generated by the combustion oxidant due to the heat exchange action of the heat storage portion. It is used for heating, the temperature of the exhaust gas is constant over time, and it is discharged outside the system at a low temperature. Moreover, since the combustion is continuously performed, fluctuations in the pressure inside the furnace due to the combustion are reduced to a negligible level. Further, since the exhaust gas is sucked into the heat storage body from around the flame when it is discharged to the outside, a so-called exhaust gas internal recirculation action occurs in which the exhaust gas and the flame are mixed, and as a result, the NO _x value is drastically reduced. However, low pollution is exhibited.

In addition, since it is unnecessary to attach an oxidizer preheater, a waste heat boiler, etc., the size of the entire furnace is reduced,
A large site is not required, construction costs can be reduced, and it becomes a compact and low-priced tube heating furnace heating device.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a tubular heating furnace according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a cross-sectional view of a combustion device.

FIG. 4 is a sectional view taken along line 4-4 of FIG.

FIG. 5 is a graph showing an experimental result of the combustion apparatus of the present invention.

FIG. 6 is a graph showing experimental results relating to NO _X emission values of the combustion device.

FIG. 7 is a graph showing an experimental result relating to a pressure fluctuation in a furnace of the combustion apparatus.

FIG. 8 is a perspective view in which an end surface of a conventional tubular heating furnace is cut away.

FIG. 9 is a plan view showing another conventional tubular heating furnace.

[Explanation of symbols]

30 ... Combustion device, 31 ... Burner, 3
2 ... Heat storage body, 36 ... Oxidant supply passage, 37 ... Exhaust gas discharge passage, 39 ... Main body case, 58 ... Fuel pipe, 59 ... Air pipe, H ... Combustion chamber, P ... Heating pipe.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Kaji 2-12-1, Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Chiyoda Kakoh Construction Co., Ltd. (72) Yoshiyuki Yusa, Tsurumi-chuo, Tsurumi-ku, Yokohama, Kanagawa Chome 12-1 Chiyoda Kakoh Construction Co., Ltd. (72) Inventor Yuji Fukuda 2-12-1 Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Chiyoda Kakoh Construction Co., Ltd.

Claims (20)

[Claims] 1. A heating pipe (P) in which a fluid to be heated flows
Is installed in the combustion chamber (H) and a combustion device (30) for injecting a flame is provided in the combustion chamber (H), and the heat of the flame causes the fluid to be heated inside through the heating pipe (P). In the heating method of a tubular heating furnace adapted to heat the oxidant, the combustion device (30) is an oxidant supply passage (36) through which an oxidant flows.
The discharged oxidant is passed through a part of the heat storage body (32) provided on the wall of the combustion chamber (H) and the heat storage body (32)
The method for heating a tubular heating furnace is characterized in that the oxidant passing region in the above is changed with time. 2. The combustion device (30) includes an oxidant supply passage (3).
The heating method for a tubular heating furnace according to claim 1, wherein the heat storage body (32) and the heat storage body (32) rotate relative to each other. 3. The number of revolutions of the oxidant supply passage (36) is 1 revolution per minute or more, preferably 2 to 4 revolutions.
The method for heating a tubular heating furnace according to. 4. The oxidant supply passage (36) discharges the oxidant from one or more outlet portions toward the heat storage body (32). Heating method of tubular heating furnace. 5. The outlet portion of the oxidant supply passage (36) is
The tube type heating according to claim 1, characterized in that it is covered with a large number of small holes that are closed by an end plate that is opened to discharge the oxidizer at high speed to the heat storage body (32). How to heat the furnace. 6. The combustion device (30) supplies motive air through the inside of the burner (31).
The method for heating a tubular heating furnace according to. 7. The ratio of the motive air to the theoretical air amount is 2 to 15%.
The method for heating a tubular heating furnace according to. 8. The combustion device (30) supplies motive steam through the inside of the burner (31).
The method for heating a tubular heating furnace according to. 9. The ratio of the motive vapor to the fuel is 0.1 to 0.1 per 10,000 calories of the calorific value of the fuel.
The heating method for a tubular heating furnace according to claim 8, wherein the heating amount is 0.8 kg. 10. The heating method for a tubular heating furnace according to claim 1, wherein the heat storage body (32) is made of ceramics. 11. A heating tube in which a fluid to be heated flows
(P) is placed inside the combustion chamber (H) and
A combustion device (30) for injecting a flame is provided, and the heat of the flame heats the fluid to be heated inside through the heating pipe (P). The device (30) is a burner (31) for heating the heating pipe (P).
An oxidant supply passage (36) for supplying an oxidant to this burner (31), an exhaust gas exhaust passage (37) for exhausting the exhaust gas after combustion to the outside of the combustion chamber (H), and an exhaust gas exhaust It is composed of a permeable heat storage body (32) that heats the oxidant by sensible heat, and this heat storage body (32) is provided on the wall of the combustion chamber (H), and from the oxidant supply passageway (36). Heating of a tubular heating furnace, characterized in that the discharged oxidant passes through a part of the heat storage body (32) and the oxidant passing region of the heat storage body (32) is changed with time. apparatus. 12. The combustion device (30) includes an oxidant supply passage.
The heating device for a tubular heating furnace according to claim 11, characterized in that the (36) and the heat storage body (32) rotate relative to each other. 13. The oxidizing agent supply passage (36) discharges the oxidizing agent toward the heat storage body (32) from one or more outlet portions. Tube heating furnace heating device. 14. The oxidant supply passage (36) is provided in a main body case (39) provided so as to communicate with the heat storage body (32), and the exhaust gas discharge passage (37) is provided in a heat storage body. The heating device for a tubular heating furnace according to claim 11, wherein the heating device is formed independently. 15. The main body case (39) is divided by the one or more oxidant supply passages (36) provided inside, and the exhaust gas discharge passageway is provided between the oxidant supply passages (36). (37) The heating device for a tubular heating furnace according to claim 14, wherein the heating device is (37). 16. The oxidant supply passages (36) are arranged so as to be arranged alternately with the exhaust gas discharge passages (37) around a burner (31) inserted through the body case (39). The heating device for a tubular heating furnace according to claim 15, wherein the heating devices are arranged at intervals. 17. The pipe type according to claim 11, wherein the oxidant supply passage (36) is configured such that the outlet portion is closed by an end plate having a large number of small holes. Heating device for heating furnace. 18. The heating apparatus for a tubular heating furnace according to claim 11, wherein the burner (31) has an air pipe (59) for supplying motive air therein. 19. The heating apparatus for a tubular heating furnace according to claim 11, wherein the burner (31) has a pipe (59) for supplying motive steam therein. 20. The heating device for a tubular heating furnace according to claim 11, wherein the heat storage body (32) is made of ceramics.