JP2710225B2 - Heat exchanger for condenser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for a condenser used in a condenser for recovering condensable components (such as water vapor) from combustion exhaust gas from a thermal power plant or a general industrial boiler.

[0002]

2. Description of the Related Art In a steam turbine power plant or the like, a sensible heat recovery device such as a economizer or an air preheater is installed in order to improve thermal efficiency, and sensible heat of boiler exhaust gas is recovered. If the fuel is a high water content fuel such as liquefied natural gas (LNG),
Since the exhaust gas contains a large amount of water vapor, it has been proposed to recover the latent heat of the water vapor to further improve the efficiency. Since LNG is a clean energy source mainly composed of hydrocarbons containing no corrosive components such as sulfur, corrosive substances such as sulfuric acid are not generated even when latent heat is recovered,
No risk of low temperature corrosion. For this reason, condensers are actively used in thermal power generation boilers and the like that use LNG as fuel.

As a cooling pipe 15 of a conventional heat exchanger for a condenser, there is a vertically arranged pipe having a smooth outer peripheral surface as shown in FIGS. Also, as shown in FIGS.
Are provided with a large number of annular fins 17 on the outer periphery thereof. In these heat exchangers, chilled water 16 flows through the cooling pipe 15 to cool the gas 2 containing condensed components flowing outside the pipe and to condense the water vapor contained therein, thereby recovering the heat possessed by the gas. The temperature of the cold water 16 is increased. The liquid condensed on the outer circumference of the pipe descends along the cooling pipe 15 or the fins 17 due to gravity, and is collected by a recovery device (not shown) provided at a lower part of the cooling pipe 15.
The collected water is used for boiler water supply.

[0004]

However, in the former smooth tube, the condensate is blown downstream by the gas flow in the heat exchanger while descending along the outer surface. Further, the conditioned latter fin cooling tubes, the droplets in the course of flowing down from the fin is blown blown to the downstream side by the gas flow. As a result, the gas flowing in the heat exchanger contains droplets, the flow resistance of the gas increases , the load on the ventilator 6 increases, and the gas flows.
The fan 6 and the chimney 7 are significantly corroded. As a measure against this
An eliminator with a gas-liquid separation function is placed immediately below the heat exchanger 5.
It is considered to be installed on the flow side to capture and remove water vapor in exhaust gas.
available. However, if the eliminator is installed downstream,
The pressure loss increases significantly, and the load on the ventilator 6 becomes excessive.
It is not preferable because it becomes large. Furthermore, the re-evaporation of these scattered droplets deteriorates the latent heat recovery characteristics of the condenser.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for controlling the flow of combustion exhaust gas from a combustor.
To prevent condensate from being blown downstream.
Therefore, it is an object of the present invention to provide a condenser heat exchanger capable of quickly collecting condensed liquid from the outer surface of a cooling pipe, suppressing an increase in gas flow resistance, and achieving excellent latent heat recovery characteristics. And

[0006]

A heat exchanger for a condenser according to the present invention is disposed so as to intersect an airflow of a combustion exhaust gas containing a condensed component, a refrigerant flows through the inside, and an outer periphery of the heat exchanger.
A surface provided substantially vertically to condense the condensed component
And a fin provided on an outer peripheral surface of the cooling pipe at least on a side where the gas flow collides, and the fin is configured such that the condensed component condensed due to the collision of the gas flow.
To prevent the cooling pipe from leaving and scattering downstream.
At least a part thereof in the flow direction of the gas flow.
A predetermined angle is provided vertically above the
Windbreak to reduce the wind hit of the gas flow against the outer peripheral surface of the pipe
And a guide for allowing the condensed component to flow along the cooling pipe.

[0007] Incidentally, the fins are preferably provided obliquely vertically downward along the flow direction of the gas flow. Further, it is desirable that a plurality of cuts are provided at the tip of the fin.

[0008]

In the heat exchanger for a condenser according to the present invention, since the gas flow that is going to collide with the outer surface of the cooling pipe is weakened by the windproof portion of the fin, the condensate is not blown off. It flows down along the outer surface of the cooling pipe. In addition, the condensate collected on the fins is guided downward by the fin guides and discharged, so that the condensate is blown away.
Collected immediately before .

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be described below with reference to the accompanying drawings. In the present embodiment, a case of a heat exchanger for a condenser provided in a steam turbine power plant will be described.

As shown in FIG. 1, the steam turbine power plant has a steam system and an exhaust gas system. In the steam system, LNG is burned in the boiler 1, and the generated steam is sent to the steam turbine 8 to rotate the generator 11, and then condensed in the condenser 9. The condensed water is pressurized by the pump 10,
After being preheated by the economizer 3, the process returns to the boiler 1. The dashed line in the figure indicates the steam cycle. Also, the solid line in the figure,
Dashed and dotted lines represent the exhaust gas 2 and the working heat medium 12 respectively.
(Hereinafter abbreviated as heat medium) and the flow of combustion air 14 are shown.

On the other hand, in the exhaust gas system, the exhaust gas 2 emitted from the boiler 1 passes through a economizer 3, an air preheater 4, a heat exchanger 5 for condensate and latent heat recovery, and a chimney 7 by a ventilator 6. Is released into the atmosphere. Each temperature entered in the figure is the temperature of the exhaust gas 2 and the temperature of the heat medium 12 at the entrance and exit of the heat exchanger 5.

The heat exchanger 5 is a condensing heat exchanger in which the exhaust gas 2 and the heat medium 12 exchange heat in a countercurrent manner. The temperature of the flowing exhaust gas 2 is 110 ° C. and the water vapor concentration is about 17 mol.
% (Dew point temperature about 55 ° C). On the other hand, the inlet temperature of the heat medium 12 is 35 ° C. Since the exhaust gas 2 is cooled to a temperature equal to or lower than the dew point temperature by the heat medium 12, condensation of the contained water vapor occurs. At this time, not only the latent heat of water vapor but also the sensible heat of the exhaust gas is deprived, so that the exhaust gas temperature drops significantly and the outlet temperature becomes 50 ° C. (that is, the temperature drop in the condenser is 60 ° C.). On the other hand, the heat medium 12 recovers the latent heat of steam and the sensible heat of exhaust gas and raises the temperature to 50 ° C., but supplies heat to the attached heat pump 13 to lower the temperature and returns to the heat exchanger 5 again. The water condensed in the heat exchanger 5 is used as boiler feed water or the like.

Next, the cooling pipes 15 arranged inside the main body of the heat exchanger 5 will be described in detail with reference to FIGS. A large number of cooling pipes 15 are arranged substantially vertically inside the main body of the heat exchanger 5 so that a refrigerant flows therethrough. Boiler exhaust gas 2 is introduced into the main body of the heat exchanger 5 at a predetermined flow rate. The exhaust gas 2 flows in a direction (horizontal direction) orthogonal to the cooling pipe 15, and exchanges heat between the exhaust gas 2 and the refrigerant via the pipe wall of the cooling pipe 15.

The cooling pipe 15 is provided with annular fins 20 of a special shape at a predetermined pitch interval substantially perpendicular to the pipe axis. Each fin 20 is provided with a plurality of cuts 23 from the outer peripheral side toward the inner peripheral side. Further, the outer peripheral portion 21 having the cut 23 is bent at a certain angle vertically upward with respect to a horizontal plane. The outer peripheral portion 21 has a role as a windproof portion that weakens the momentum of the exhaust gas 2 colliding with the outer peripheral surface of the pipe.

Incidentally, not only the outer peripheral portion 21 but also the entire annular fin 20 may be bent upward with respect to the horizontal plane. In addition, four drain holes 22 are provided in the vicinity of the fin 20 where the fin 20 is attached to the cooling pipe 15 in order to lower the condensate along the cooling pipe 15. These drain holes 22 serve as guides for discharging the condensed liquid, and at least one drain hole may be provided.

Although the fin 20 shown in FIGS. 2 and 3 has a structure in which a number of annular plates are independently attached to the tube 15, the ribbon-like plate is continuously spirally formed in the circumferential direction of the cooling tube 15. To form a fin.

The cooling pipe 15 was a steel pipe for a boiler, and the fin 20 was a steel strip having a thickness of about 1 to 2 mm.
The fins 20 are fixed to the outer peripheral surface of the cooling pipe 15 by welding.

When the exhaust gas 2 flows perpendicular to the row of the cooling pipes 15, the condensed components in the exhaust gas condense on the surfaces of the cooling pipes 15 and the fins 20 to generate a condensate. The condensate tends to fall or fall from the cooling pipe 15 or the fin 20 due to gravity, but tends to be blown off when the gas flow rate is high. However, the fin outer peripheral portion 21
As a result, the collision force of the gas 2 is reduced, the condensed liquid is received by the annular fins 20 inclined upward, and the liquid is held so as not to be scattered by the capillary force generated in the narrow space of the cut 23. Then, the condensate does not scatter to the downstream side. Then, the condensate is drained from the drain hole 2 provided at a position where the condensed liquid is hardly blown off by the gas flow of the fin 20.
2 and flows along the outer peripheral surface of the cooling pipe 15,
It is collected in the lower collecting device.

According to the above embodiment, the efficiency of recovering the condensed components in the exhaust gas is greatly improved by installing the fin having a simple structure suitable for mass production. In addition, since the condensed liquid is not scattered, the flow resistance of the gas in the heat exchanger body does not increase, and the latent heat recovery characteristics are further improved.

Next, another embodiment will be described with reference to FIGS. In this embodiment, a large number of inclined fins 30 are attached to the outer periphery of the cooling pipe 15 at a predetermined pitch. As shown in FIG. 4, the inclined fins 30 are provided to be inclined vertically downward along the flow direction of the exhaust gas 2.
On the gas collision side (upstream side) of the inclined fin 30, a windbreak part 31 is formed in a manner similar to that shown in FIG. 2, so that the collision force of the exhaust gas 2 on the outer peripheral surface of the cooling pipe 15 is reduced. I have. A discharge passage 32 is formed on the gas wrap side (downstream side) of the inclined fin 30, and condensate is collected along the fin 30 and discharged downward through the drain groove 32.

According to the above embodiment, the condensed liquid is guided to the gas wraparound side, and is discharged therefrom via the drain groove 36. Therefore, the condensed liquid is further less affected by the gas flow, and the gas flow rate is reduced. Is large, the condensed liquid can be reliably collected without scattering.

[0022]

According to the present invention, since the gas flow which is going to collide with the outer surface of the cooling pipe is weakened by the windproof portion of the fin, the condensate flows down along the outer surface of the cooling pipe without being blown off. . For this reason, an area with gas-liquid separation function
Even if a minator is not specially installed on the downstream side,
Can be separated and removed, increasing gas flow resistance.
Better without increasing the pressure drop
Latent heat recovery can be realized. In addition, the condensate collected on the fin is guided downward by the drain hole of the fin and discharged, so that the condensate is blown away.
Collected immediately before . Thus the condensate re-evaporates
Recovery time before condensate recovery
As well as significantly improve the latent heat recovery characteristics of the condenser
Is done. Furthermore, liquid does not enter the downstream side of the heat exchanger.
As a result, the load on the ventilator does not increase, and
Corrosion of the cut wall is reduced.

[Brief description of the drawings]

FIG. 1 is a system flow diagram showing an outline of a steam turbine power plant.

FIG. 2 is a side view showing a cooling pipe provided in the condenser heat exchanger according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a cooling pipe provided in the condenser heat exchanger according to the embodiment of the present invention.

FIG. 4 is a side view showing a cooling pipe provided in a condenser heat exchanger according to another embodiment.

FIG. 5 is a cross-sectional view showing a cooling pipe provided in a heat exchanger for a condenser according to another embodiment.

FIG. 6 is a diagram showing a conventional heat exchanger.

FIG. 7 is a diagram showing a conventional heat exchanger.

FIG. 8 is a view showing a conventional heat exchanger.

FIG. 9 is a view showing a conventional heat exchanger.

[Explanation of symbols]

 2: Exhaust gas 5: Heat exchanger body 15: Cooling pipe 20, 30 ... Fin 21, 31: Windproof part 22: Drain hole (guide part) 23: Cut 32: Drain groove (guide part)

Claims (3)

(57) [Claims] Claims: 1. A refrigerant is arranged so as to intersect with an airflow of a combustion exhaust gas containing a condensed component, and a refrigerant flows through the inside thereof.
Provided substantially vertically on the outer peripheral surface for condensing the condensed component
It was a cooling tube, comprising: a fin at least the gas flow is provided on the outer peripheral surface of the cooling tube side of collision, and the fins, condensed the condensed component of the gas flow Opposition
A collision prevents the cooling pipe from leaving and scattering downstream.
At least a portion of said gas stream to stop
Provided at a predetermined angle vertically above the direction,
Reduce the wind contact of the gas flow against the outer peripheral surface of the cooling pipe
A heat exchanger for a condenser, comprising: a windbreak section; and a guide section for allowing the condensed component to flow along the cooling pipe. 2. The fin according to claim 1, wherein the fin is arranged in
It is characterized by being provided vertically inclining along
The heat exchanger for a condenser according to claim 1, wherein 3. A plurality of cuts are formed at the tip of the fin.
2. A condensation device according to claim 1, further comprising:
Dexterous heat exchanger.