JPH10237450A - Heat recovery apparatus of coke dry-quenching apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost heat recovery apparatus of a coke dry-quenching apparatus which can prevent the corrosion of a heat transfer pipe of a feedwater preheater as far as possible while increasing the capability of a coke dry- quenching apparatus. SOLUTION: The second water-water heat exchanger 35 is installed in between a degasifier 31 of the second feedwater pipe 18 supplying boiler feedwater to a heat exchanger 19 of a water heat recovery boiler 15 and the waste heat recovery boiler 15, and the temp. of the feedwater supplied through the first feedwater pipe 27 to a feedwater preheater 24 is elevated by boiler feed water supplied from the degasifier 31 to the heat exchanger 19. Therefore, the rate of corrosion of the heat transfer pipe of the feedwater preheater 24 can be greatly reduced and the life of the preheater 24 can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat recovery apparatus for a coke dry fire extinguishing system used to recover heat from waste gas generated when cooling red hot coke.

[0002]

2. Description of the Related Art Conventionally, as a heat recovery apparatus for a coke dry fire extinguishing system, a circulating gas is circulated between a chamber and a waste heat recovery boiler, and about 1050 gases are introduced into the chamber.
In some cases, red-hot coke of ℃ is cooled to 200 ° C. and taken out, and heat is exchanged with a waste heat recovery boiler to generate steam. In addition, in such a heat recovery device of a coke dry-type fire extinguishing system, the boiler feedwater supplied to the waste heat recovery boiler is heated in advance, and the temperature of the cooled circulating gas supplied to the chamber is further reduced. In some cases, a feedwater preheater is provided in the middle of a chamber from a waste heat recovery boiler.

[0003] In recent years, as a measure to increase the capacity of coke dry fire extinguishing equipment, measures have been taken by introducing air into the chamber and burning red hot coke.
In this case, the temperature of the combustion portion in the chamber becomes high, which adversely affects the refractory or impairs the cooling capability of the red hot coke, so that the amount of introduced air is limited. For this reason, by introducing steam into the circulating gas, heat is absorbed by the aqueous gasification reaction of the red hot powder coke, and together with the cooling of the coke, hydrogen gas is generated. The amount of heat to the side is increased to increase the generation of steam. However, in this case, since the water vapor partial pressure in the circulation system increases, the water dew point rises.If such operation is continued, the heat transfer pipe of the feed water preheater may increase corrosion due to the rise in the water dew point temperature. is there.

Therefore, as a device capable of increasing the temperature of water supplied to a water supply preheater, Japanese Patent No. 2556596 discloses a heat recovery system for a dry coke fire extinguishing system. Apparatus B is shown in FIG. As shown in the figure, the heat recovery apparatus B of the coke dry fire extinguishing equipment includes a first heat exchanger 51 installed in a circulating gas duct, a second heat exchanger 52 provided in a boiler water supply line, and both heat exchangers. The circulation circuit 53 includes a closed circulation circuit 53 that connects the circulation circuits 51 and 52, and a circulation pump 54 that circulates the heat medium sealed in the circulation circuit 53.

In such a heat recovery apparatus B of a coke dry fire extinguishing system, the circulating gas (1000 ° C. or higher) that extinguished red hot coke in a cooling tower (chamber) 61 is sent to a waste heat recovery boiler 63 through a dust catcher 62. There, heat exchange with boiler feedwater takes place. The circulating gas (about 190 ° C.) after the completion is sent to the first heat exchanger 51 by the blower 64, where the circulating gas (about 150 ° C.) that has given heat to the heat medium is introduced into the cooling tower 61, and the red hot coke To cool.

On the other hand, the boiler feed water (about 20 ° C.) stored in the feed water tank 67 is supplied by the pump 68 to the second heat exchanger 5.
The temperature is raised (about 65 ° C.) in 2 and sent to the deaerator 69 to be deaerated. Thereafter, the waste heat recovery boiler 6 is driven by the pump 70.
The water is supplied to 3 and heat exchanges with high-temperature circulating gas to form steam. On the other hand, the heat medium (about 95 ° C.) from which the heat of the circulating gas has been recovered by the first heat exchanger 51 reaches the second heat exchanger 52 and heats the boiler feedwater. Thereafter, the heat medium (70 ° C.) is again circulated to the first heat exchanger 51 by the circulation pump 54.

With this configuration, even when the feedwater temperature is low, such as at the start of operation or when the load fluctuates, if the temperature of the heat medium is maintained at an appropriate level, the temperature of the first heat exchanger 51 can be reduced to the water dew point temperature of the circulating gas ( 40 ° C.) or more, and corrosion of the pipe wall surface and adhesion of dust can be prevented.

[0008]

However, the heat recovery apparatus B for the coke dry-type fire extinguishing system described above still has the following problems to be solved. That is, in the heat recovery apparatus B of the coke dry fire extinguishing equipment described above, the first heat exchanger 51
Constitutes a part of the closed circulation circuit 53, it is necessary to take measures to release an increase in pipe pressure due to thermal expansion. Therefore, the structure of the heat recovery device B of the coke dry fire extinguishing equipment is complicated and costly. Becomes

Further, in the heat recovery apparatus B of the coke dry-type fire extinguishing equipment, the heat medium circulation circuit and the boiler water supply line are separate systems, so that the equipment cost also increases from this aspect. The present invention has been made in view of such circumstances, and an inexpensive coke dry type that can prevent corrosion of a heat transfer tube of a water supply preheater as much as possible while increasing the capacity of a coke dry fire extinguishing system. An object of the present invention is to provide a heat recovery device for a fire extinguishing system.

[0010]

According to the present invention, there is provided a semiconductor device comprising:
The heat recovery device of the described coke dry fire extinguishing equipment feeds a high-temperature circulating gas derived from a chamber of the coke dry fire extinguishing equipment to a waste heat recovery boiler through a high-temperature gas supply pipe,
The heat exchange is performed by a heat exchanger disposed in the waste heat recovery boiler, the low-temperature circulating gas after the heat exchange is returned to the chamber through a low-temperature gas supply pipe, and the boiler water from a water supply source is supplied to the heat exchanger. The heat exchange is performed by supplying heat through a first water supply pipe to a water supply preheater attached to a low-temperature gas supply pipe to further cool the low-temperature circulating gas supplied into the chamber and to perform the heat exchange on the boiler. Feed water is supplied to the heat exchanger in the waste heat recovery boiler through a second water supply pipe, and steam generated by the heat exchanger in the waste heat recovery boiler is supplied to the boiler feed water in the second water supply pipe. In a heat recovery apparatus of a coke dry-type fire extinguishing facility equipped with a deaerator for increasing the temperature of the boiler feed water by mixing a part of the boiler feed water, the deaerator of the second feed pipe and the deaerator A second water / water heat exchanger is attached to a part between the heat recovery boiler and the boiler water supplied from the deaerator to the heat exchanger of the waste heat recovery boiler. The temperature of feedwater supplied to the feedwater preheater through the feedwater pipe is raised.

According to a second aspect of the present invention, there is provided a heat recovery apparatus for a coke dry fire extinguishing facility, wherein the temperature of the water supplied to the water preheater through the first water supply pipe is different from that of the first embodiment. Is set to 60 ° C. to 90 ° C. The heat recovery apparatus for a coke dry-type fire extinguishing facility according to claim 3 is the heat recovery apparatus for a coke dry-type fire extinguishing facility according to claim 2, wherein the second water / water heat exchanger comprises a heating side. A bypass passage is formed in parallel with the main flow path portion of the water supply pipe, and a flow rate control valve is attached to the bypass flow path to adjust the amount of the boiler water flowing through the main flow path portion and the bypass flow path. Thereby, the feedwater temperature supplied to the feedwater preheater through the first feedwater pipe is set at 60 ° C to 90 ° C.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

First, a heat recovery apparatus A of a coke dry fire extinguishing system according to an embodiment of the present invention will be described with reference to FIG. As shown in the figure, a chamber 10 constituting a main part of a coke dry fire extinguishing system has a coke inlet 11 for charging coke (about 1050 ° C.) in a red hot state at an upper part thereof, and a cooling part at a lower part thereof. Coke outlet 1 for removing coke (about 200 ° C)
2 is provided. A hot gas outlet 13 is provided at an upper portion of the chamber 10, and the hot gas outlet 13 is connected to a hot gas inlet 16 provided at an upper portion of the waste heat recovery boiler 15 through a hot gas supply pipe 14. .
A dust catcher 17 for collecting dust in the high-temperature circulating gas is provided in the middle of the high-temperature gas supply pipe 14.

A heat exchanger 19 is provided in the waste heat recovery boiler 15 so as to communicate with a second water supply pipe 18. The boiler feed water flowing through the heat exchanger 19 and the waste heat recovery boiler 15 Hot circulating gas (about 9
50 ° C.). A low-temperature gas outlet 20 is provided at a lower portion of the waste heat recovery boiler 15, and a low-temperature gas outlet 20 is provided at a lower portion of the chamber 10 through a low-temperature gas supply pipe 22 having a circulating gas blower 21. It is communicatively connected to. Also,
A water supply preheater 24 is mounted in the middle of the low-temperature gas supply pipe 22. A first water supply pipe having one end connected to a water supply inlet 26 of the water supply preheater 24 is connected to a water supply tank 26 which is an example of a water supply source. The other end of 27 is communicatively connected. A first water supply pump 28 is attached to the first water supply pipe 27.

One end of a second water supply pipe 18 is connected to the water outlet 29 of the water supply preheater 24, and the other end of the second water supply pipe 18 is connected to the waste heat recovery boiler 15 as described above.
Is connected to the heat exchanger 19 in the inside. A first water / water heat exchanger 30 is mounted in the middle of the second water supply pipe 18, and the boiler water flowing in the second water supply pipe 18 is the boiler water supply flowing in the first water supply pipe 27. And heat exchange will take place between them.

In the portion of the second water supply pipe 18 downstream of the first water / water heat exchanger 30, steam supplied from a steam supply pipe 33 described later is used to supply boiler water. A deaerator 31 used to remove dissolved oxygen and the like contained therein, and a second water supply pump for pumping boiler feedwater passing through the deaerator 31 toward the heat exchanger 19 in the waste heat recovery boiler 15. 32 are attached. A steam supply pipe 33 is communicatively connected to the outlet side of the heat exchanger 19 in the waste heat recovery boiler 15, a steam supply pipe 34 is branched from the steam supply pipe 33, and a steam supply pipe 34 is partially branched. Supply pipe 34
Is connected to a portion immediately upstream of the deaerator 31.

The heat recovery apparatus A of the coke dry-type fire extinguishing equipment according to the present embodiment is designed to prevent corrosion of the heat transfer tube of the water supply preheater 24 in the heat recovery apparatus A of the coke dry-type fire extinguishing equipment in addition to the above-described configuration. It is characterized by adding the following configuration. That is, as shown in FIG. 1, in the second water supply pipe 18, the deaerator 31 and the waste heat recovery boiler 15
A second water / water heat exchanger 35 is attached to a portion between the two.

The heating side of the second water / water heat exchanger 35 is connected to the second water supply pipe 18, and the heat receiving side is connected to the first water supply pipe 18.
Is connected to a water supply pipe 27 of Therefore, the deaerator 31
The retained heat of the high-temperature (105 ° C.) boiler feedwater is given to the normal-temperature boiler feedwater flowing through the first water supply pipe 27, and the boiler feedwater can be heated (30). ° C → 50 ° C). On the other hand, due to the heating effect described above, the waste heat recovery boiler 15
On the contrary, the temperature of the boiler feed water supplied to the heat exchanger 19 in the inside is reduced (105 ° C. → 85 ° C.).

Next, a coke dry extinguishing method and a heat collecting method by the heat recovery apparatus A of the coke dry extinguishing equipment having the above-described configuration will be described. In the present embodiment, the first water supply pipe 27 is connected from the water supply tank 26 to the water supply preheater 24.
The boiler water supplied through the sewage system is initially at room temperature (approximately 3
(0 ° C.), but in the middle of the feeding, first, heat is received by the second water / water heat exchanger 35 and the temperature is raised to 50 ° C.

Next, the heat is received by the first water / water heat exchanger 30 and the temperature is raised to 80 ° C., and then the water is supplied to the feed water preheater 24. Low-temperature circulating gas (about 180 ° C.) fed from the waste heat recovery boiler 15 in the feed water preheater 24
Is further cooled (about 130 ° C.). On the other hand, the boiler feedwater discharged from the feedwater preheater 24 is from 80 ° C to 110 ° C.
Temperature. As described above, in the present embodiment, the boiler feedwater flowing through the first feedwater pipe 27 is received by the second water / water heat exchanger 35 and the first water / water heat exchanger 30, and is then preheated. The temperature of the boiler feedwater fed to the feedwater preheater 24 is 80 ° C.
It has become. Therefore, the corrosion rate of the heat transfer tube of the feed water preheater 24 can be remarkably reduced, and the life of the feed water preheater 24 and the life of the heat recovery device A of the coke dry fire extinguishing equipment can be extended.

FIG. 2 shows the relationship between the life of the heat transfer tube of the feed water preheater 24 and the feed water temperature of the boiler feed water fed to the feed water preheater 24. FIG. 2 shows a case in which a circulating gas in which water vapor is mixed into N ₂ gas at 5%, 10%, and 15% (all by volume) is used. FIG.
As is apparent from, for example, water vapor in the N ₂ gas 5
When the boiler feed water to the feed water preheater 24 is 30 ° C., the life of the feed water preheater 24 is 1.3 years, whereas the boiler feed water to the feed water preheater 24 is 60%. ℃, the life of the feed water preheater 24 is 8.0
When the boiler feedwater to the feedwater preheater 24 is 75 ° C., the life of the feedwater preheater 24 is 10.0 years. As described above, by increasing the temperature of the boiler feedwater fed to the feedwater preheater 24, the life of the feedwater preheater 24, and hence the life of the heat recovery device A of the coke dry-type fire extinguishing equipment, can be extended.

The feed water preheater 24 is connected to the second feed water pipe 1.
8. Since the steam supply pipe 33 is connected to the steam supply pipe 33 through the heat exchanger 19 of the waste heat recovery boiler 15 and has an open flow path, even if the heat transfer pipe of the water supply preheater 24 expands due to a temperature rise, the pressure increases. The rise can be quickly absorbed and the heat transfer tube rupture accident can be reliably prevented.

Thereafter, the boiler feed water is supplied to the deaerator 31 for the second time.
The first water / water heat exchanger 30 heats the water from the second water supply pipe 18 to the first water supply pipe 27 during the water supply. Therefore, the temperature of the boiler feed water drops from 110 ° C. to 80 ° C., and then the boiler feed water is supplied to the deaerator 31. A part of the steam is supplied from the steam supply pipe 33 to the deaerator 31 through the partial steam supply pipe 34 together with the boiler supply water, so that the temperature of the boiler supply water is raised (about 105 ° C.). ).

However, in the present embodiment, the second water / water heat exchanger 35 is provided downstream of the deaerator 31.
The heat supplied from the second water supply pipe 18 to the first water supply pipe 27 lowers the temperature of the boiler water in the second water supply pipe 18, and the temperature in the waste heat recovery boiler 15 is reduced to 85 ° C., which is significantly lower than the conventional temperature (105 ° C.). Is supplied to the heat exchanger 19. Therefore, the low-temperature gas outlet 2 of the waste heat recovery boiler 15
The temperature of the boiler outlet gas of the circulating gas flowing out from zero can also be a temperature (about 160 ° C.) that is 20 ° C. lower than the conventional boiler outlet gas temperature (about 180 ° C.).

By the way, the amount of circulating gas with respect to the gas temperature at the boiler outlet, and the chamber 1 of the coke dry fire extinguishing system
0 coke throughput and waste heat recovery boiler 15
Is as shown in FIG. That is, a second water / water heat exchanger 35 is provided in a portion of the second water supply pipe 18 downstream of the deaerator 31 to reduce the temperature of the circulating gas at the boiler outlet gas from about 180 ° C to about 1 ° C.
By reducing the temperature to 60 ° C., the flow rate of the circulating gas supplied to the chamber 10, the amount of coke treated by the chamber 10, and the amount of steam generated in the waste heat recovery boiler 15 are reduced.
Each will be able to increase significantly.

In the coke dry extinguishing method and heat recovery method using the heat recovery apparatus A of the coke dry extinguishing equipment described above, the supply temperature of the boiler feed water to be supplied to the heat transfer tube of the feed preheater 24 is 60 ° C. to 90 ° C. It is preferable to set. If the feed temperature of the boiler feed water exceeds 90 ° C,
The effect of extending the life of the feed water preheater 24 cannot be expected much, and even if it can be expected, it is necessary to balance the life of other equipment of the heat recovery device A of the coke dry fire extinguishing equipment. On the other hand, when the supply temperature of the boiler supply water is lower than 60 ° C., the life cannot be sufficiently extended in relation to the life of the other equipment of the heat recovery device A of the coke dry fire extinguishing equipment.

Further, in the present embodiment, as shown in FIG. 1, the bypass pipe is provided in parallel with the main flow path portion 18a of the second water supply pipe 18 constituting the heating side of the second water / water heat exchanger 35. A flow path 36 is formed, and a flow rate control valve 37 is attached to the bypass flow path 36. And the flow control valve 3
Reference numeral 7 is electrically connected to a temperature sensor 38 provided in the first water supply pipe 27.

Therefore, the water supply preheater 2
Even when the temperature of the boiler feedwater flowing through the first feedwater pipe 27 changes toward 4, the temperature is detected by the temperature sensor 38, and the opening and closing of the flow control valve 37 is controlled based on the detected result. By adjusting the amount of boiler feed water flowing through the main flow path portion 18a and the bypass flow path 36, the amount of heat given from the boiler feed water of the second feed pipe 18 to the boiler feed water of the first feed pipe 27 is adjusted. The feed water temperature of the boiler feed water to be supplied to the heat transfer tubes of the feed water preheater 24 can be maintained at 60C to 90C.

As described above, the present invention has been described with reference to one embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and is described in the claims. It also includes other embodiments and modifications that can be considered within the scope of the matters described.

[0030]

According to the heat recovery apparatus for a coke dry fire extinguishing system according to the first to third aspects, the deaerator and the waste heat recovery of the second water supply pipe for supplying boiler water to the heat exchanger of the waste heat recovery boiler are provided. A second water / water heat exchanger is attached to a part between the boiler and the boiler water supplied to the heat exchanger of the waste heat recovery boiler from the deaerator to the water supply preheater through the first water supply pipe. The temperature of the supplied water is raised. Therefore, the corrosion rate of the heat transfer tube of the feedwater preheater can be significantly reduced, and the life of the feedwater preheater and, consequently, the life of the heat recovery device of the coke dry fire extinguishing equipment can be extended.

Further, by providing a second water / water heat exchanger at a portion downstream of the deaerator of the second water supply pipe, the boiler feed water supplied to the heat exchanger of the waste heat recovery boiler is provided. Since the temperature can be significantly reduced, the boiler outlet gas temperature of the circulating gas in the waste heat recovery boiler can also be significantly reduced, and the amount of circulating gas supplied to the chamber of the coke dry fire extinguishing equipment, the amount of coke processed by the chamber, and the The amount of steam generated can each be significantly increased. The feed water preheater communicates with the steam feed pipe via the second feed water pipe and the heat exchanger of the waste heat recovery boiler, and has an open flow path. Even if it expands, the pressure rise can be quickly absorbed, and the rupture of the heat transfer tube can be reliably prevented.

In particular, in the heat recovery apparatus of the coke dry-type fire extinguishing equipment according to the second aspect, the supply water temperature of the boiler supply water to be supplied to the heat transfer tube of the water supply preheater is set at 60 to 90 ° C. Therefore, it is possible to extend the life of the water supply preheater while maintaining the balance with the life of other equipment of the heat recovery device of the coke dry fire extinguishing equipment.

According to a third aspect of the present invention, in the heat recovery apparatus for a coke dry-type fire extinguishing system, a bypass passage is provided in parallel with a main flow path of a second water supply pipe constituting a heating side of the second water / water heat exchanger. Is formed and a flow control valve is attached to the bypass flow path. Therefore, by controlling the opening and closing of the flow control valve, the amount of boiler feed water flowing through the main flow path portion and the bypass flow path is adjusted, and the amount is supplied from the boiler feed water of the second feed pipe to the boiler feed water of the first feed pipe. By adjusting the amount of heat, the feed water temperature of the boiler feed water to be supplied to the heat transfer tube of the feed water preheater can be maintained at 60 ° C to 90 ° C. Therefore, it is possible to more reliably extend the life of the water supply preheater while balancing the life of the heat recovery device of the coke dry fire extinguishing equipment with the life of other devices.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a heat recovery device of a coke dry fire extinguishing facility according to an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the life of a heat transfer tube of a feed water preheater and the feed water temperature of boiler feed water fed to the feed water preheater.

FIG. 3 shows the boiler outlet gas temperature of the circulating gas flowing out of the waste heat recovery boiler, the flow rate of the circulating gas supplied to the chamber of the coke dry fire extinguishing equipment, the coke treatment amount by the chamber, and the steam generation amount in the waste heat recovery boiler. 6 is a graph showing the relationship of.

FIG. 4 is a block diagram showing the overall configuration of a conventional heat recovery device for a coke dry fire extinguishing facility.

[Explanation of symbols]

A Heat recovery device for coke dry fire extinguishing equipment 10 Chamber 11 Coke inlet 12 Coke outlet 13 Hot gas outlet 14 Hot gas supply pipe 15 Waste heat recovery boiler 16 Hot gas inlet 17 Dust catcher 18 Second water supply pipe 18a Main flow path Part 19 Heat exchanger 20 Low temperature gas outlet 21 Circulating gas blower 22 Low temperature gas supply pipe 23 Low temperature gas inlet 24 Water supply preheater 25 Water inlet 26 Water supply tank (water supply source) 27 First water supply pipe 28 First water supply pump 29 Water flow Outlet 30 First water / water heat exchanger 31 Deaerator 32 Second water supply pump 33 Steam feed pipe 34 Partial steam supply pipe 35 Second water / water heat exchanger 36 Bypass flow path 37 Flow control valve 38 Temperature sensor

Claims (3)

[Claims] 1. A high-temperature circulating gas derived from a chamber of a coke dry fire extinguishing system is supplied to a waste heat recovery boiler through a high temperature gas supply pipe, and heat is exchanged by a heat exchanger disposed in the waste heat recovery boiler. And the low-temperature circulating gas after the heat exchange is returned to the chamber through a low-temperature gas supply pipe, and boiler water supplied from a water supply source is supplied to a water supply preheater attached to the low-temperature gas supply pipe by a first water supply pipe. Through which heat is exchanged, the temperature of the low-temperature circulating gas supplied into the chamber is further lowered, and the boiler feedwater after the heat exchange is passed through a second water supply pipe to exchange heat in the waste heat recovery boiler. And a part of steam generated by a heat exchanger in the waste heat recovery boiler is mixed into the boiler feedwater in the second water supply pipe. -In a heat recovery apparatus of a coke dry fire extinguishing facility equipped with a deaerator for increasing the temperature of the feedwater, a second part of the second water supply pipe between the deaerator and the waste heat recovery boiler; Water supplied from the deaerator to the heat exchanger of the waste heat recovery boiler and supplied to the water supply preheater through the first water supply pipe by the water / water heat exchanger. A heat recovery device for a coke dry fire extinguishing facility, wherein the temperature is raised. 2. The coke dry fire extinguishing system according to claim 1, wherein the temperature of the feed water supplied to the feed water preheater through the first feed water pipe is set at 60 ° C. to 90 ° C. Heat recovery device. 3. A bypass flow path is formed in parallel with a main flow path portion of the second water supply pipe constituting a heating side of the second water / water heat exchanger, and a flow rate is adjusted in the bypass flow path. A valve is attached, and by adjusting an amount of the boiler feedwater flowing through the main flow path portion and the bypass flow path, a feedwater temperature supplied to the feedwater preheater through the first feedwater pipe is reduced to 60 ° C to 90 ° C. 3. The heat recovery device for a coke dry fire extinguishing system according to claim 2, wherein the heat recovery device is set.