JPH10332101A - Disposition structure of waste heat recovery boilers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable full operation of heat source equipment even when periodic inspection of waste heat recovery boilers is taken into account, by providing the waste heat recovery boiler for each of a plurality of branch flues branching from the outlet of a main flue leading out waste gas from a heat source. SOLUTION: This waste heat recovery system comprises a blower 3 and an air duct 4 for sending air to a heat source 2, a main flue 5 for leading out waste gas from the heat source 2, a first flue 7 and a second flue 8 branching off in two from the outlet 6 of the main flue 5, a first waste heat recovery boiler 10 provided for the first flue 7 and a second waste heat recovery boiler 40 provided for the second flue 8. A first inlet damper 20 and a first inlet shielding mechanism 30 are provided for the first flue 7 so that the first inlet damper 20, the first inlet shielding mechanism 30 and the first waste heat recovery boiler 10 are disposed in this sequence, while a second inlet damper 50, a second inlet shielding mechanism 60 and the second waste heat recovery boiler 40 are provided for the second flue 8 in this sequence.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a layout of a waste heat recovery boiler.

[0002]

2. Description of the Related Art For example, there is an ore sintering facility as a facility before a blast furnace (blast furnace). The purpose is to efficiently charge raw materials into a blast furnace to increase productivity, and to lump fine iron ore by a sintering method. Since it is a sintering method, it is necessary to heat iron ore to a temperature just before melting (sintering temperature), and the retained heat is enormous. Therefore, techniques for recovering this heat with a waste heat recovery boiler have been put into practical use (for example, Japanese Patent Publication No. 58-15709, Japanese Patent Publication No. 58-15).
No. 710).

[0003] The layout of a waste heat recovery boiler similar to the equipment of the above publication will be described with reference to the following figure. FIG. 6 is a flow chart showing an example in which a conventional waste heat recovery boiler is arranged in a flue. A wind is sent to a heat source 101 such as a sintering facility by a blower 102 and a blow duct 103, and the obtained hot wind is smoked. Waste heat recovery boiler 110 attached to the flue 104
There is a known heat recovery technology.

[0004] The waste heat recovery boiler 110 includes a water tank 1.
11, deaerator 112, economizer 113, evaporator 11
4, a second evaporator 115, a steam drum 116, a pump 117,... (Several numbers are shown, the same applies hereinafter), and pipes.
The gas degassed in 12 is heated by the economizer 113 and then sent to the steam drum 116. The hot water of the steam drum 116 is heated by the evaporator 114 and further by the second evaporator 115 to raise the temperature and return to the steam drum 116, separated into steam and hot water by the steam drum 116, and the steam is transferred to the steam transport pipe 11.
8 can be taken out. During this time,
The hot air from the heat source 101 flows as shown by the arrows, and the second evaporator 115, the evaporator 114, the economizer 113
Heat exchange in this order, and it becomes low-temperature air and moves away from the boiler.

[0005]

SUMMARY OF THE INVENTION Waste heat recovery boiler 11
In the case of 0, it is necessary to carry out a periodic inspection according to the regulations, and during this time, the line must be stopped by stopping the sintering equipment. If it is a major facility such as a boiler for power generation, there is no problem in incorporating periodic inspections into the annual plan and stopping on a line-by-line basis. However, the waste heat recovery boiler 110 poses a problem because it is a secondary facility and the heat source facility is the main facility. That is, if the downtime is, for example, about 10 hours once a month, the productivity of the heat source equipment is 2%.
Will also decrease.

Accordingly, an object of the present invention is to provide a technique capable of fully operating a heat source facility even in anticipation of periodic inspection of a waste heat recovery boiler.

[0007]

Means for Solving the Problems To achieve the above object, a first aspect of the present invention provides a main flue and a blower for extracting waste gas from a heat source, a plurality of branch flues from an outlet of the main flue, This is a layout structure of a waste heat recovery boiler including a waste heat recovery boiler provided in each of these branch flues.

When a certain waste heat recovery boiler is inspected, heat is recovered by continuing the operation of the remaining waste heat recovery boiler. Therefore, it is possible to fully operate the heat source equipment even when anticipating the periodic inspection of the waste heat recovery boiler. In addition, since the boilers are provided in parallel, the pressure loss in the boiler and the flue before and after the boiler is reduced, and the capacity of the blower can be increased accordingly, and the total heat recovery amount can be greatly increased.

[0009] The second aspect of the present invention provides an inlet damper for a branch flue.
An inlet damper and an inlet shield mechanism are provided in the order of the inlet shield mechanism and the waste heat recovery boiler, the inlet damper is closed, and then the flue is completely shielded by the inlet shield plate. I do. When shutting down a waste heat recovery boiler, shut off the line's entrance damper,
Next, if the entrance shielding mechanism is closed, the waste heat recovery boiler can be inspected. Since the entrance damper and the entrance shielding mechanism are provided in series, the pressure resistance and heat resistance of the entrance shielding mechanism are not so required, and the structure can be simplified.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. In the embodiment, the number of branch flues is set to two, and they will be referred to as “first flue” and “second flue”.

FIG. 1 is a flow chart showing an arrangement example of a waste heat recovery boiler according to the present invention. The blower 3 sends air to a heat source 2 and a blow duct 4, a main flue 5 which guides waste gas from the heat source 2, and the like. A first flue 7 and a second flue 8 branching from the outlet 6 of the main flue 5, a first waste heat recovery boiler 10 provided in the first flue 7, and a second flue 8 Waste heat recovery system comprising a second waste heat recovery boiler 40 provided in
In the first flue 7, the first inlet damper 20 and the first inlet shielding mechanism 30 are provided in the order of the first inlet damper 20, the first inlet shielding mechanism 30, and the first waste heat recovery boiler 10,
The second flue 8 is provided with a second inlet damper 50 and a second inlet shielding mechanism 60 in the order of a second inlet damper 50, a second inlet shielding mechanism 60, and a second waste heat recovery boiler 40. I do. The heat source 2 includes a sintering facility, an incinerator, a coke oven, and the like, and the type is not limited.

The first waste heat recovery boiler 10 includes a water supply tank 11, a deaerator 12, a economizer 13, an evaporator 14, a second evaporator 15, a steam drum 16, a pump 17,.
The water supplied from the water supply tank 11 is vacuum-degassed by the deaerator 12, heated in the economizer 13, and then sent to the steam drum 16. The hot water of the steam drum 16 is heated by the evaporator 14 and further by the second evaporator 15 to increase the temperature and return to the steam drum 16, separated into steam and hot water by the steam drum 16, and the steam is passed through the steam transport pipe 18. It can be taken out.

During this time, half of the hot air from the heat source 2 flows as shown by the arrow, and exchanges heat in the order of the second evaporator 15, the evaporator 14, and the economizer 13, and becomes low-temperature air and moves away from the boiler 10.

Similarly, the second waste heat recovery boiler 40 includes a water supply tank 41, a deaerator 42, a economizer 43, an evaporator 44, a second evaporator 45, a steam drum 46, a pump 47, and piping. The water supplied from the water supply tank 41 is vacuum-degassed by the deaerator 42, heated in the economizer 43, and then sent to the steam drum 46. The hot water of the steam drum 46 is heated by the evaporator 44 and further by the second evaporator 45 to raise the temperature and return to the steam drum 46, separated into steam and hot water by the steam drum 46, and the steam is passed through the steam transport pipe 48. It can be taken out.

During this time, half of the hot air from the heat source 2 flows as shown by the arrow, and exchanges heat in the order of the second evaporator 45, the evaporator 44, and the economizer 43, and turns into low-temperature air and moves away from the boiler 40.

FIG. 2 is a principle diagram of an entrance damper and an entrance shielding mechanism according to the present invention.
Numeral 0 denotes a damper shaft 21, damper plates 22 attached to the damper shaft 21, and the damper shaft 21.
Actuator 90 that rotates 90 degrees through arm 23
Consists of The actuator 24 is preferably an electric cylinder or a pneumatic cylinder, and moves the damper plates 22, 22 in the fully open state shown by the solid line as indicated by arrows to open and close the flow path in a short time so as to be in the fully closed state. Drive unit. 25, 25 are stoppers. Since the second inlet damper 50 shown in FIG. 1 has the same structure as the first inlet damper 20, the description is omitted.

The first entrance shielding mechanism 30 includes a shielding plate 31 and
An actuator 32 moves up and down the shielding plate 31. Reference numeral 33 denotes a shielding plate storage part provided in the middle of the first flue 7, 3.
Reference numerals 4 and 34 denote sealing materials, and 35 denotes a gantry. The actuator 32 is preferably an electric cylinder or a hydraulic cylinder. FIG.
The second entrance shielding mechanism 60 shown in FIG.
0, the description is omitted.

As shown by the white arrow, when the waste gas is flowing, the first inlet damper 20 is closed, and after confirming the closing, the shielding plate 31 is lowered to block the flow path. In order to restart the flow from the shielding state, the shielding plate 31 is raised, and after confirming the full opening, the first inlet damper 20 is fully opened.

It is possible to provide only one of the first entrance damper 20 and the first entrance shielding mechanism 30, and to open and close the flow path. In this case, the first inlet damper 2
Since the airtightness of the zero must be increased, the damper becomes complicated and expensive. Alternatively, since high-pressure, high-temperature waste gas directly acts on the shielding plate 31, the shielding plate 31 needs to be rugged and have a water-cooled structure, and the first entrance shielding mechanism 30 is complicated and expensive.

In this regard, in this embodiment, since the first inlet damper 20 is disposed on the upstream side and the first inlet shielding mechanism 30 is disposed on the downstream side, first, the pressure and temperature of the waste gas are reduced by the first inlet damper 20. After that, the first entrance shielding mechanism 30 is operated, so that the shielding plate 31 does not require pressure resistance and heat resistance, a simple and lightweight one can be adopted, and the cost of the first entrance shielding mechanism 30 can be reduced. Since the first inlet damper 20 does not require airtightness, a simple and lightweight one can be employed. The same applies to the second entrance damper 50 and the second entrance shielding mechanism 60.

The operation of the arrangement structure of the waste heat recovery boiler having the above configuration will be described separately for (A) periodic inspection, (B) increase in heat recovery amount, (C) remodeling and government office inspection. (A) Periodic inspection; In FIG. 1, the first inlet damper 20, the first inlet shielding mechanism 30, and the second inlet damper 50 are usually used.
Then, the second inlet shielding mechanism 60 is opened, and the waste gas from the heat source 2 is sent to the first waste heat recovery boiler 10 and the second waste heat recovery boiler 40 to recover heat therefrom. When the first waste heat recovery boiler 10 comes to the inspection time, the first inlet damper 50 and the second inlet shielding mechanism 60 are kept open and the first
The entrance damper 20 and the first entrance shielding mechanism 30 are closed.
While operating the second waste heat recovery boiler 40, the first waste heat recovery boiler 10 can be inspected. When the second waste heat recovery boiler 40 comes to the inspection time, the reverse may be performed.

(B) Increase in heat recovery amount; FIGS. 3 (a) and 3 (b)
Is a pressure system diagram. (A) shows a comparative example according to the prior art described in FIG. 6, in which the flow rate of waste gas flowing through the flue is q, the pressure gradient from the blower to the heat source outlet is Δp1, and the pressure gradient from the heat source outlet to the boiler outlet is q. Δp2, total pressure gradient Δ
Let ptotal = Δp1 + Δp2. (B) is an embodiment according to the present invention, in which the flow of the waste gas flowing from the blower to the heat source is Q, the pressure gradient from the blower to the heat source outlet is ΔP11,
The flow rate of the waste gas flowing through the flue is 0.5 × Q, the pressure gradient from the heat source outlet to the first boiler outlet is ΔP12, and the total pressure gradient is ΔP1total = ΔP11 + ΔP12. The flow rate of the waste gas flowing through the second flue is 0.5 × Q, the heat source outlet to the second
The pressure gradient to the boiler outlet is ΔP22, and the total pressure gradient is ΔP2total = ΔP11 + ΔP22.

The pressure loss of the passage is proportional to the gas density × passage loss coefficient × (flow rate) ^2/2 g. g is the gravitational acceleration. If the flow area of the flue in (a) is the same as the flow area of the first and second flue in (b), and if there is almost no difference in gas density × flow path loss coefficient, the first The gas velocities in the flue and the second flue are halved, and ΔP12 is Δp2
And ΔP22 are also １ ／ of Δp2. ΔP1to
Since both tal and ΔP2total can be made substantially equal to Δptotal, ΔP11 can be made sufficiently larger than Δp1. That is, Q = (1.3-1.
6) × q, and this increase in waste gas flow rate directly leads to an increase in heat recovery. Specific numerical values will be described in the “Example” section below.

(C) Remodeling and Government Inspection: In order to modify the pressure resistance of boilers (portion subject to governmental inspection), conventionally, it is necessary to stop the line, carry out the remodeling work, and undergo a line inspection by the government office. Had to be stopped continuously. In contrast, the first waste heat recovery boiler 10
When remodeling, the second waste heat recovery boiler 40 can be operated. Similarly, when modifying the second waste heat recovery boiler 40, the first waste heat recovery boiler 10
Can be operated. Therefore, even when remodeling and receiving inspection by government offices, it is not necessary to stop the heat source equipment, so that the waste heat recovery plan can be maintained at a high level.

FIG. 4 is a view showing another embodiment of FIG. 1. Only points different from FIG. 1 will be described. A first outlet shielding mechanism 70 and a first outlet damper 72 are provided in this order at the outlet of the first flue 7. After that, the first flue 7 is connected to the blower suction duct 74, and the second flue 8 has a second outlet shielding mechanism 76 and a second
After the outlet dampers 78 are provided in this order, the second flue 8 is connected to the blower suction duct 74 to form a closed cycle. Other components are the same as those in FIG. 1, and the detailed description is omitted by using the reference numerals.

The first and second outlet blocking mechanisms 70 and 76 are the same as the first and second inlet blocking mechanisms 30 and 60, and the first and second outlet dampers 72 and 78 are connected to the first and second inlets. It is the same as the dampers 20, 50.

The operation of the other embodiment will be described. Normally,
The first inlet damper 20, the first inlet shielding mechanism 30, the first outlet shielding mechanism 70, and the first outlet damper 72 are opened, heat is recovered by the first waste heat recovery boiler 10, and the second inlet damper 50, The second inlet shield mechanism 60, the second outlet shield mechanism 76, and the second outlet damper 78 are opened, and heat is recovered by the second waste heat recovery boiler 40.

When inspecting the first waste heat recovery boiler 10, first, the first inlet damper 20 and the first outlet damper 72 are closed. Since waste gas is flowing through the second flue 8,
It is temporarily fastened with the dampers 20, 72. Therefore, the entrance side is arranged in the order of the damper → the shielding mechanism, and the exit side is arranged in the order of the shielding mechanism → the damper. Next, the first inlet shielding mechanism 30 and the first outlet shielding mechanism 70 inside (closer to the first waste heat recovery boiler 10) are closed. The same applies when the second waste heat recovery boiler 40 is inspected.

FIG. 5 is a view showing another embodiment of FIG. 2. The first inlet damper 20B at the lower right of the figure comprises a plurality of damper plates 81... (Three in this example) and a damper shaft 82.・ ・
. Are mounted on the damper shafts 82..., Each of which is connected to each other by a link plate 84.
Are directly or indirectly moved up and down by the actuator 85, so that the damper plates 81 are rotated by 90 degrees. Although the structure is slightly complicated, the stroke of the actuator 85 is small, the time required for the opening and closing operation is short, and the working time can be shortened.

The first entrance shielding mechanism 30B includes a shielding plate 86.
And a rope 87, a pulley 88, and a winch 89 for raising and lowering the shielding plate 86. Reference numeral 33 denotes a shielding plate storage provided in the middle of the first flue 7, and reference numerals 34, 34 denote sealing materials,
Reference numeral 5 denotes a gantry.

As described above, the dampers 20, 20
B and 50 may be either a single-plate damper (see FIG. 2) or a split-type damper (see FIG. 5). In addition, the shielding mechanism 3
The actuators 0, 30B, and 60 may be cylinders (see FIG. 2) or winches (see FIG. 5).
Means for raising and lowering the shielding plates 31 and 86 are optional.

In the embodiment, two branch flues are used.
There may be three or more. In the case of two pipes, the flow area of the branch flue is basically the same as that of the main flue. In the case of three, since the flow area of the remaining two branch flue may be the same as that of the main flue, the flow area of each branch flue is
(The area of the flow path of the main flue) / 2 may be sufficient. The same applies to four or more pipes, and the flow passage area of each branch flue is (flow passage area of the main flue) /
(Number of branch flues-1) is sufficient, and it is possible to make the branch flue thinner and reduce the capacity of the boiler as the number increases.

However, when three or more pipes are used, the branch flue is made thinner, and the capacity of the boiler is made smaller, the increase in waste heat recovery during normal operation is not as expected as when two pipes are used. Therefore,
The flow path area of each branch flue may be determined based on the following equation, and the inner diameter may be determined from the flow path area.

[0034]

(Equation 1)

When Sb = Sm, a sufficiently large amount of heat recovery can be expected, but the equipment cost increases. Conversely, Sm / (n-1)
If = Sb, the equipment cost can be reduced, but the increase in the amount of heat recovery is not so expected. When there are three or more branch flues, all of the branch flues do not need to have the same flow passage area, and each may be within the range of the above formula. As a result, it becomes possible to connect two or more smaller-diameter branch flues to the existing large-diameter flue.

Further, the present invention can be changed to the equipment of the present invention of FIG. 1 only by adding the second flue 8 and the second waste heat recovery boiler 40 to the conventional equipment of FIG. It can also be applied to retrofitting existing equipment. Moreover,
In claim 1, a flange portion into which a blind plate can be inserted into the first flue and the second flue is provided upstream of the first and second waste heat recovery boilers, and only when necessary, A blind plate may be inserted into one of the flues.

[0037]

EXAMPLES Examples according to the present invention will be shown below, but the present invention is not limited to these examples. Comparative example: Equipment layout Fig. 6 (Blower 1 + heat source 1 + boiler 1) Air volume of blower 500 × 10 ³ NM ³ / hour (N is normal) Boiler pressure loss 145 mmAq Boiler steam generation 44 t / hour (t is ton)

Example: Equipment Layout FIG. 1 (Blower 1 + Heat Source 1 + Boiler 2) Air Volume of Blower 744 × 10 ³ NM ³ / hr (N is Normal) Boiler Pressure Loss 45 mmAq First Boiler Steam Generation 32.8 t / H (t is ton) Second boiler steam generation 32.8 t / h (t is ton)

Evaluation: As described with reference to FIG. 3, two boilers were installed in parallel, and in this embodiment, the air volume was 74
It could be increased to 4 × 10 ³ NM ³ / hour. By supplying 1/2 of this, that is, 372 × 10 ³ NM ³ / hour, to the first boiler (first waste heat recovery boiler), 32.8 t / hour of steam could be obtained in the first boiler. Similarly, 32.8 t / h of steam could be obtained in the second boiler. As a result, the steam generation amount of the comparative example was 4
At 4 t / h, the amount of steam generated in the example is 32.8 × 2 = 65.
Since the rate was 6 t / hour, the heat recovery amount of the example was increased by about 50% of the comparative example.

[0040]

According to the present invention, the following effects are exhibited by the above configuration. Claim 1 comprises a main flue and a blower that guide waste gas from a heat source, a plurality of branch flues branched from an outlet of the main flue, and a waste heat recovery boiler provided in each of these branch flues. It is an arrangement structure of a waste heat recovery boiler.

When checking a waste heat recovery boiler, the operation of the remaining waste heat recovery boiler is continued to recover heat. Therefore, it is possible to fully operate the heat source equipment even when anticipating the periodic inspection of the waste heat recovery boiler. In addition, since the boilers are provided in parallel, the pressure loss in the boiler and the flue before and after the boiler is reduced, and the capacity of the blower can be increased accordingly, and the total heat recovery amount can be greatly increased.

[0042] The second aspect of the present invention provides an inlet damper for a branch flue,
An inlet damper and an inlet shield mechanism are provided in the order of the inlet shield mechanism and the waste heat recovery boiler, the inlet damper is closed, and then the flue is completely shielded by the inlet shield plate. I do. When shutting down a waste heat recovery boiler, shut off the line's entrance damper,
Next, if the entrance shielding mechanism is closed, the waste heat recovery boiler can be inspected. Since the entrance damper and the entrance shielding mechanism are provided in series, the pressure resistance and heat resistance of the entrance shielding mechanism are not so required, and the structure can be simplified.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of an arrangement of a waste heat recovery boiler according to the present invention.

FIG. 2 is a principle diagram of an entrance damper and an entrance shielding mechanism according to the present invention.

FIG. 3 Pressure system diagram

FIG. 4 is a view showing another embodiment of FIG. 1;

FIG. 5 is a diagram showing another embodiment of FIG. 2;

FIG. 6 is a flowchart showing an example in which a conventional waste heat recovery boiler is arranged in a flue.

[Explanation of symbols]

2: heat source, 3: blower, 5: main flue, 6: exit of main flue, 7: branch flue (first flue), 8: branch flue (second flue), 10: waste heat Recovery boiler (first waste heat recovery boiler), 20, 20B ... inlet damper (first inlet damper), 30, 30B ... inlet shielding mechanism (first inlet shielding mechanism), 31, 86 ... shielding plate, 40 ... waste heat Recovery boiler (second waste heat recovery boiler), 50 inlet damper (second
Entrance damper), 60 ... entrance shielding mechanism (second entrance shielding mechanism).

Claims (2)

[Claims] 1. A main flue and a blower for extracting waste gas from a heat source, a plurality of branch flues branched from an outlet of the main flue, and a waste heat recovery boiler provided in each of these branch flues. Structure of waste heat recovery boiler. 2. An entrance damper, an entrance shielding mechanism, and an entrance damper and an entrance shielding mechanism are provided in the branch flue in the order of an entrance damper, an entrance shielding mechanism, and a waste heat recovery boiler, and the entrance damper is closed.
2. The arrangement of claim 1, wherein the flue is completely shielded by the entrance shield plate.