JPS6158750B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a waste heat recovery device (waste heat exchanger for heat recovery)
This relates to a double cylindrical vertical kiln equipped with a double cylinder type vertical kiln.

In the conventional double cylindrical vertical firing furnace, for example, as shown in Japanese Patent Publication No. 52-46560, a heat exchanger for waste heat recovery is installed in the upper part of the inner cylinder of the furnace body.
Combustion air is heated by waste gas after firing.

However, conventional vertical kilns having built-in heat exchangers for waste heat recovery have the following drawbacks.

(1) Since the heat exchanger was installed inside the furnace body, the size of the heat exchanger was limited, making it impossible to increase the heat transfer area and increase the amount of heat recovery.

(2) Since the waste gas flows in from the bottom of the heat exchanger and is discharged from the top, the waste gas flows in the opposite direction to the direction of gravity, causing dust to become suspended and stick to the inside of the heat exchanger pipes, causing the pipes to become clogged. occlude.

(3) If there is a problem such as a pipe blockage, it is difficult to clean because it is installed inside the furnace body.

(4) It cannot be inspected because it is installed inside the furnace.

In order to eliminate the above-mentioned drawbacks and obtain a vertical kiln that smoothly performs the firing of limestone with maximum heat recovery and effective utilization, the present invention provides a circular inner cylinder approximately concentric with the kiln body inside the kiln main body. , After blowing combustion gas from the combustion means into the firing space between the furnace body and the inner cylinder, and causing a part of the combustion gas to rise from the injection point as a counterflow to the object to be fired, the firing is performed. a waste heat recovery device that heats the air supplied to the combustion means with combustion waste gas containing dust after firing, and firing by lowering the other part of the combustion gas from an injection point in parallel flow with the object to be fired. and a means for causing the descended combustion gas to rise in the lower inner cylinder space of the inner cylinder and then to flow back to the combustion means. The waste heat recovery device is installed outside the furnace main body, and the waste heat recovery device is provided with a waste gas inflow chamber communicating with the inside of the kiln at the top, and a first partition plate below the waste gas inflow chamber. A heat exchange chamber is provided below the heat exchange chamber, and a second partition plate is provided below the heat exchange chamber.
The heat exchange chamber includes an inlet for cold air, which is air to be heated, in the lower part, and heated air in communication with the combustion means of the kiln in the upper part. A discharge port is provided in the heat exchange chamber, and both upper and lower ends thereof penetrate through the first partition plate and the second partition plate, respectively, and are opened into the waste gas inflow chamber and the waste gas discharge chamber. A large number of waste gas conduits are arranged in the circumferential direction with their axes facing up and down, and furthermore, a cold air outlet is provided in the upper part of the heat exchange chamber at a position close to the first partition plate, and a cold air outlet is provided in the lower part of the heat exchange chamber at a position close to the first partition plate. A cold air inlet located near the cold air inlet of the heat exchange chamber, and several cold air supply tubes arranged at appropriate intervals in the circumferential direction with their axes facing up and down. By using a vertical kiln equipped with a waste heat recovery device provided with pipes, reliable and effective heat exchange can be carried out, and the number of heat source units in the kiln can be significantly reduced. This is what I did.

Next, one embodiment of a vertical firing furnace equipped with a waste heat recovery device of the present invention will be described with reference to the drawings.

FIG. 1 shows a vertical kiln equipped with the waste heat recovery device of the present invention.

The vertical firing furnace has a nearly concentric circular inner cylinder 2 in the furnace body 1, with firing spaces 3a, 3b, 3c,
3d and 3e, and an upper stage 11 in the firing space.
The inner cylinder 2 is connected to the furnace body 1 by providing three bridges: a, a middle stage 11b, and a lower stage 12.

An intermediate wall 4 is provided at a predetermined position of the inner cylinder 2 to divide the inner cylinder space 5 into an upper space 5a and a lower space 5b, and a firing space 3 and an upper and lower space above the upper bridge 11a and below the lower bridge 12. 5
Ventilation holes 6a and 6b are provided, respectively, to communicate with a and 5b.

Then, an upper burner 9a and a lower burner 9b are provided outside the furnace body 1, and combustion chambers 10a and 10b are provided, respectively.
10b and opens into the firing space 3 from below the upper bridge 11a and from below the intermediate bridge 11b.

The combustion space 3 includes a preheating firing space 3a above the upper ventilation hole 6a, an upper firing space 3b between the upper ventilation hole 6a and the upper stage burner 9a, a middle firing space 3c between the upper stage burner 9a and the lower stage burner 9b, and a lower stage between the upper stage burner 9a and the lower stage burner 9b. The lower firing space 3 is located between the burner 9b and the lower ventilation hole 6b.
d, and a cooling firing space 3e below the lower ventilation hole 6b.

The bridges 11a, 11b, 12 are provided at appropriate positions in the vertical direction between the furnace body 1 and the inner cylinder 2 at appropriate intervals in the circumferential direction, and each bridge 11a, 11b, 12 is provided in each firing space 3b, 3c, 3d and 3e are set so as to allow the object to be fired to descend smoothly.

The burners 9a and 9b in the upper and lower stages are also installed in the circumferential direction of the furnace body 1 along with the firing chambers 10a and 10b, without being limited to two stages as shown in FIG. In addition, these burners 9a, 9b, the firing chamber 10
a and 10b constitute firing means.

Air to the burners 9a and 9b enters the waste heat recovery device 15 from a blower (not shown) through the conduit 22, and exchanges heat with the waste gas extracted from the inner cylinder 2 and introduced into the waste heat recovery device 15. After being heated by
Then, the upper and lower burners 9a, 9 are connected through the conduit 25.
b and to the injector 14 by a conduit 27.

The waste heat recovery device 15 is installed outside the furnace body 1 and alongside the furnace body 1 . The inside of the inner cylinder 2 and the waste gas inlet 15d of the waste heat recovery device 15 described below
and is communicated with by a waste gas extraction pipe 19.

FIG. 2 is a longitudinal sectional view of the waste heat recovery device of the present invention.

The main body of the waste heat recovery device 15 includes a heat exchange chamber 15b located in the middle, and a waste gas inflow chamber via a first partition plate 15m and a second partition plate 15n at the upper and lower parts of the heat exchange chamber 15b, respectively. 15a and a waste gas discharge chamber 15c are combined.

The waste gas inlet chamber 15a has waste gas inlets 15 on both sides.
d and 15d are provided, each of which has a waste gas extraction pipe 19.
It is directly connected to and communicates with the inside of the inner cylinder 2 of the vertical firing furnace.

The heat exchange chamber 15b has an elongated cylindrical shape as shown in FIG. 2, and has an exhaust port 15e for heated air after heat exchange at the top, and an inlet 15f for cold air at the bottom.
has been established.

The heated air outlet 15e is connected to the conduit 2 as described above.
3 to the annular conduit 13a, and the cold air inlet 15f communicates to the air outlet of a blower (not shown) via the conduit 22. The heated air outlet 15e is attached to a hot air chamber 15g provided in the upper part of the heat exchange chamber 15b, and the cold air inlet 15f is attached to a cold air chamber 15h provided in the lower part of the heat exchange chamber 15b.

The hot air chamber 15g or the cold air chamber 15h and the heat exchange chamber 15b are communicated through through holes 15i and 15j, respectively.

A large number of flat baffle plates 15k are installed at regular intervals inside the heat exchange chamber 15b.

The baffle plate 15k is divided into two types, large and small.

Large baffle plate 15k ₁ has almost the outer diameter of heat exchange chamber 1
5b, and has a hole 15l in the center for passing cold air.

The small diameter baffle plate 15k ₂ has its outer end and the heat exchange chamber 1
A slight gap 15p is provided between the inner wall and the inner wall 5b, and heated air is allowed to rise through this gap 15p.

These two types of large and small baffle plates 15k ₁ and 15k ₂ are arranged in series over the entire length of the heat exchange chamber 15b, every other one.

Baffle plates 15k ₁ , 15 are provided inside the heat exchange chamber 15b.
Numerous straight pipes 15 as waste gas conduits passing through k ₂
Arrange s.

As shown in FIG. 2, the straight pipe 15s has its upper end penetrating the first partition plate 15m and slightly protruding into the waste gas inlet chamber 15a. Further, the lower end of the straight pipe 15s passes through the second partition plate 15n and projects into the exhaust gas discharge chamber 15c.

The upper and lower ends of the straight pipes 15s are connected to the first and second partition plates 15m and 15n.
A plurality of (six in this embodiment) cold air supply pipes 15t are provided, which do not penetrate through the straight pipe 15s and are arranged at appropriate intervals in the circumferential direction, and are arranged parallel to the straight pipe 15s. These are attached to the baffle plate 15k. At the upper end of this cold air supply pipe 15t,
Cold air outlet 1 adjacent to the first partition plate 15m
5t2 is opened by cutting a part of the pipe wall, and a cold air inlet is located at the lower end of the cold air supply pipe 15t near the cold air inlet 15f of the heat exchange chamber 15b. 15t1 is provided by cutting out a part of the tube wall and opening it.

By providing such a cold air supply pipe 15t, a part of the cold air introduced from the cold air introduction port 15f of the heat exchange chamber 15b is transferred into the inside of the cold air supply pipe 15t. It flows in from the inflow port 15t1, rises within the cold air supply pipe 15t, and is discharged from the cold air outlet 15t2, and then passes through the first partition plate 15.
Cool evenly over the entire surface.

This is to prevent temperature rise and corrosion of the first partition plate 15m, which is in direct contact with high-temperature waste gas, and to maintain a balance in the arrangement of the straight pipes 15s due to thermal expansion.

As shown in FIG. 2, the exhaust gas discharge chamber 15c has a tapered conical shape, and the exhaust gas discharge chamber 15q is located at the tip.
form.

The waste gas discharge chamber 15q is communicated via a conduit 28 with an inlet of an exhaust fan (not shown).

Next, the operation of the present invention configured as described above will be explained.

A part of the waste gas combusted in the combustion chamber 10a of the upper stage burner 9a flows counter-currently to the object to be fired in the upper firing space 3b, heating the object to be fired while passing through the bridge 11a.
After rising from the gap, it continues to rise to the preheating combustion space 3a, and after preheating the object to be fired, it is discharged to the outside of the furnace body 1 by an exhaust means (not shown).

In addition, a part of the waste gas enters the upper inner cylinder space 5a of the inner cylinder 2 through the upper ventilation hole 6a, and further passes through the exhaust gas extraction pipe 19 and flows into the waste gas inlet 15d of the waste heat recovery device 15. It flows into the chamber 15a.

This waste gas passes through the first partition plate 15m and projects into the waste gas inflow chamber 15a through a straight pipe 15s.
It flows into the straight pipe 15s through the opening of the straight pipe 15s and descends inside the straight pipe 15s.

On the other hand, the cold air passes through the conduit 22, enters the cold air chamber 15h provided in the heat exchange chamber 15b from the cold air inlet 15f, and then enters the heat exchange chamber 1 from the through hole 15j.
It is sent to the lower part of 5b.

This cold air advances from the lower part to the upper part of the heat exchange chamber 15b.

At that time, the cold air is passed through the hole ₁₅ of the large baffle plate 15k1.
1 and small baffle plate 15k ₂ circumferential end and heat exchange chamber 15
It exchanges heat with the waste gas in the straight pipe 15s while passing alternately through the gaps 15p between the air and the inner wall of the pipe b, and becomes hot air.

This hot air enters the hot air chamber 15g through the through hole 15j formed in the upper part of the heat exchange chamber 15b, and then passes through the conduit 23 from the discharge port 15e to the annular conduit 1.
Sent to 3a. This hot air is sent to an annular conduit 13 and supplied to an injector 14.

On the other hand, from the cold air chamber 15h to the heat exchange chamber 15b
A part of the cold air sent to the lower part of the is introduced from the cold air inlet 15t1 into the cold air supply pipes 15t, which are arranged in plurality at appropriate intervals in the circumferential direction, and the cold air is supplied to the lower part of the cold air. The air rises inside the tube 15t and is discharged from the upper cold air outlet 15t2 to the upper end of the heat exchange chamber 15b, uniformly cooling the entire surface of the first partition plate 15m. Therefore, the temperature rise and corrosion of the first partition plate 15m exposed to the high temperature atmosphere are prevented, and the arrangement balance of the straight pipe (waste gas conduit) 15s attached to the first partition plate 15m is maintained. and its deformation is also prevented.

Further, the waste gas that has undergone heat exchange is collected into the waste gas discharge chamber 15c from the lower end of the straight pipe 15s, and is further discharged outside the system from the discharge port 15q by an exhaust fan (not shown).

In this way, the waste gas from the firing furnace containing dust flows from top to bottom in the direction of gravity within the straight pipe 15s, so that the phenomenon of dust adhering to the inner wall of the straight pipe 15s is prevented, and the dust is Sticky straight pipe 1
5s will not be occluded.

The other part of the combustion gas from the upper stage burner 9a descends together with the object to be fired through the intermediate firing space 3c in a parallel flow (flow of C→), and reaches the lower stage bridge 12 through the gap of the intermediate stage bridge 11b. , heating the object to be fired in the middle firing space 3c and the lower firing space 3d;
The cooling firing space 3e passes through the gap of the lower bridge 12.
Immediately after entering the inner cylinder lower space 5 from the lower ventilation hole 6b
Enter b (flow of D→). After that, the waste gas rises in the inner cylinder lower space 5b, is blocked by the intermediate wall 4, passes through the conduit 21, and is sucked into the injector 14 together with the air from the first annular pipe 13a, and then becomes secondary air in the combustion chamber 10b. supply is becoming available.

A part of the combustion gas from the lower stage burner 9b also rises and combines with the combustion gas from the upper stage burner 9a to become a stream A or a stream B and is discharged through the preheating firing space 3a or the waste heat recovery device 15. The other part is combined with the descending C flow gas of the upper stage burner 9a, passes through the gap of the lower stage bridge 12 and the lower ventilation hole 6b, and is sucked into the injector 14 along with the D flow.

The firing effect is increased by sending a relatively small amount of air to the upper burner 9a and a relatively large amount of air to the lower burner 9b than the theoretical air amount.

Then, the three stages of bridges 11a, upper, middle, and lower,
Both of 11b and 12 have a roof-shaped upper part, making it easier for the object to be fired to descend.

In addition, in the present invention, by installing the waste heat recovery device 15 outside separately from the furnace main body, the inner cylinder 2
The upper space 5a becomes a space, and the ventilation holes 6a and 6b for high-temperature waste gas are no longer blocked by dust.
Since the ventilation pressure loss is reduced, it becomes possible to lower the wind pressure of the exhaust fan (not shown) connected to the waste gas outlet 15q at the bottom of the waste heat recovery device 15, and power is saved.

The inner tube 2 has two tubes, an outer tube 7a and an inner tube 7.
b, which are arranged concentrically with appropriate gaps between them, forming a cooling space 8 therebetween. A conduit 30 is connected from the blower 17 to this cooling space 8.
The cold air is force-fed through the cooling space 8, gains heat from the outer tube 7a, and becomes hot air through the conduits 29b and 29.
c, and is collected in the second annular conduit 13b and conduit 26
a, 26b to the burners 9a, 9b.

Further, the hearth bottom air is transferred from the blower 17 to the conduit 30,
31, enters the cooling firing space 3e through the fired product carrying out device, rises as a counterflow to the fired product, and is obstructed by the lower bridge 12 as the C flow from the burners 9a and 9b flows. and flows into the inner cylinder lower space 5b from the lower ventilation hole 6b as a flow D.

The fired product delivery device is disposed below the furnace body 1 and includes an annular delivery table 34 having a substantially conical distribution body 32 and a cam-shaped discharge body 33 directly below the distribution body 32. The discharge body 33 is driven via a pin gear 35 after the rotation of the motor 37 is reduced by a speed reducer 36 .

Since the vertical firing furnace for limestone, etc. of the present invention has the above-described structure, the materials to be fired are transported to the preheated firing space 3a between the furnace body 1 and the inner cylinder 2 by the feeding means (not shown). , and descends while being preheated by flow A which rises from the burners 9a and 9b as a counterflow to the object to be fired, and then descends from the position of the upper ventilation hole 6a provided in the inner cylinder 2, and the upper , middle and lower firing spaces 3b, 3c, and 3d, and after falling through the gap of the lower bridge 12, it is cooled in the cooling firing space 3e and reaches the fired product delivery device. During this time, since the amount of air in the lower stage burner 9b is greater than the amount of air in the upper stage burner 9a, the object to be fired is fired satisfactorily.

As is clear from the above description, since the present invention has the configuration as described in the claims, the waste gas containing dust discharged from the firing furnace to the outside of the furnace is transferred to the waste gas conduit of the waste heat recovery device. Since the waste gas flows in the upper part of the pipe, descends inside the pipe, and is discharged from the lower part, the waste gas flows in the direction of gravity. It is possible to avoid the phenomenon of floating and adhering to the inner wall of the pipe or becoming likely to stick together, and it is possible to prevent clogging of the waste gas pipe. Therefore, high heat exchange efficiency can be maintained over a long period of time, and its ability can be maximized.

The heat exchange chamber of the waste heat recovery device is provided with cold air supply pipes arranged at appropriate intervals in the circumferential direction between the plurality of waste gas pipes.
Since the first partition plate is cooled evenly over its entire surface, the temperature increase and corrosion of the first partition plate exposed to the high temperature atmosphere are prevented, and therefore the large number of parts attached to the first partition plate are prevented from increasing. The operation of the waste heat recovery device is reliably maintained without the waste gas conduit being unbalanced or the conduit itself being deformed.

Since the waste heat recovery device with this effect is installed outside the firing furnace body, the heat transfer area can be increased without being limited to the internal volume of the furnace body as in conventional firing furnaces. This makes it possible to fully utilize the waste heat of the kiln, and together with the effect of increasing the amount of heat recovery, it is possible to ensure maximum heat recovery and its effective use over a long period of time. At the same time, the number of heat source units of the kiln can be significantly reduced.

In addition, by installing the waste heat recovery device outside the kiln, internal inspection and repair of the waste heat recovery device becomes easier, and it is also possible to lower the heat resistance performance of the heat exchange chamber, making it possible to use cheaper materials. You can also use the.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a limestone kiln equipped with the waste heat recovery device of the present invention, Fig. 2 is a longitudinal sectional view of the waste heat recovery device, and Fig. 3 is a sectional view (enlarged) of AA of Fig. 2. be. 1 is a furnace body, 2 is an inner cylinder, 3 is a firing space, 3a is a preheating firing space, 3b is an upper firing space, 3c
3d is a middle firing space, 3d is a lower firing space, 3e is a cooling firing space, 4 is an intermediate wall, 5 is an inner cylinder space, 5a is an upper inner cylinder space, 5b is a lower inner cylinder space,
6a and 6b are ventilation holes, 7a is an inner pipe, 7b is an inner pipe,
8 is a cooling space, 9a is an upper burner, 9b is a lower burner, 10a and 10b are firing chambers, 11a is an upper bridge, 11b is a middle bridge, 12 is a lower bridge, 13a is an annular conduit, 13b is a second annular conduit, 14 is an injector, 15 is a waste heat recovery device, 1
7 is a blower, 19 is a waste gas extraction pipe, 21, 22,
23, 25, 27, 28, 29b, 29c, 31
32 is a conduit, 32 is a distribution body, 33 is a discharge body, 34 is an annular delivery table, 35 is a pin gear, 36 is a speed reducer, and 37 is a motor. 15a is a waste gas inflow chamber of the waste heat recovery device 15 (hereinafter referred to as the waste heat recovery device), 15b is a heat exchange chamber, 15c is a waste gas discharge chamber, 15d is a waste gas inlet, and 15e is a heated air discharge chamber. The outlet, 15f is a cold air inlet, 15g is a hot air chamber, 15h is a cold air chamber, 15i, 15j are through holes, 15k is a baffle plate, 15k ₁ is a large size, 1
5k ₂ refers to small size. 15l is a hole for passing cold air,
15m and 15n are partition plates, 15s is a straight pipe (waste gas conduit), 15t is a cold air supply pipe, 15p is a gap, and 15q is a waste gas outlet.

Claims (1)

[Claims] 1. A circular inner cylinder approximately concentric with the furnace body is provided inside the furnace body, combustion gas is blown from the combustion means into the firing space between the furnace body and the inner cylinder, and a part of the combustion gas is directed from the injection point to the surrounding area. a waste heat recovery device that heats the air supplied to the combustion means by the combustion waste gas containing dust after firing by raising it as a counterflow to the fired product; Means for causing the other part to descend from the injection point in a parallel flow with the object to be fired to perform firing, and for causing the descended combustion gas to ascend within the lower inner cylinder space of the inner cylinder and then to flow back to the combustion means. In a vertical firing furnace equipped with a waste heat recovery device, the waste heat recovery device is installed outside the furnace body, and the waste heat recovery device is communicated with the inside of the furnace at the top. a heat exchange chamber provided below this through a first partition plate, and a second heat exchange chamber provided below this through a first partition plate.
a waste gas discharge chamber provided through a partition plate and having a waste gas discharge port;
A heated air outlet communicating with the combustion means of the kiln is provided in the upper part, and the upper and lower ends of the heat exchange chamber pass through the first partition plate and the second partition plate, respectively, and the waste gas is discharged into the heat exchange chamber. A large number of waste gas conduits are opened in the inflow chamber and the waste gas discharge chamber, and are arranged circumferentially in a large number with their axes directed in the vertical direction, and further, in the heat exchange chamber, the first partition plate is provided in the upper part. A cold air outlet is provided at a close position, and a cold air inlet is located at a lower part near the cold air inlet of the heat exchange chamber, and the axis thereof is directed in the vertical direction and is spaced at appropriate intervals in the circumferential direction. A vertical firing furnace characterized by being equipped with a waste heat recovery device comprising a plurality of cold air supply pipes arranged at intervals.