JPH1123165A - Air-cooled condenser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the condensation performance of an air-cooled condenser for condensing steam by cooling with the air. SOLUTION: Steam from an inlet pipe 1 passes through an inlet chamber 2 and flows into a heating tube 3 arranged vertically. The condensate flows from an outlet chamber 4 into an outlet pipe 5 and uncondensed gas flows out from a bent pipe 6. The air flows in from below through a fan 7 being driven by a motor 8 and cools down the heating tubes 3 sequentially from the lower stage toward the upper stage. Consequently, the steam in the heating tube 3 is condensed and liquefied on the outlet side before flowing out from an outlet pipe 6. Each heating tube 3 is provided with an orifice 11 except the lowermost stage and the orifice 11 is made narrower toward the upper stage. Since the temperature difference between the steam and the air decreases toward the upper stage, the condensation capacity is decreased toward the upper stage. Heat transmission area of the heating tube 3 is utilized effectively by restricting the quantity of steam toward the upper stage so that condensation just completes on the outlet side of each heating tube 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermal power plant,
The present invention relates to an air-cooled condenser that is used for the purpose of flowing steam in a heat transfer tube, cooling the air, and condensing the steam.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration of a conventional air-cooled condenser used in a thermal power plant. A plurality of heat transfer tubes 3 arranged horizontally are connected to the inlet chamber 2 and the outlet chamber 4 to form a tube group. There is a blower duct 9 at the top of the tube bank,
A blower 7 fixed by a blower fixture 10 is installed inside the blower duct 9. Blower 7 is blower fixture 1
0 is driven by a motor 8 attached to the motor.

[0003] Steam flows into the inlet chamber 2 from the inlet pipe 1 and is distributed to the plurality of heat transfer tubes 3. Ambient air having a temperature lower than that of the steam is sucked by the blower 7 from below the lowermost heat transfer tube 3 into the inside of the tube group, passes through the tube group from bottom to top, passes through the blower 7, and is exhausted upward. You. The steam is cooled by air flowing around the outside of the tube while flowing inside the heat transfer tube 3 and condensed.
The liquids condensed in the plurality of heat transfer tubes 3 in the outlet chamber 4 merge and flow out of the outlet tube 5. Non-condensable gas 20 such as air contained in the steam is discharged from a vent pipe 6 provided in the outlet chamber 4. The vent pipe 6 is connected to a vacuum pump (not shown).

In the air-cooled condenser having such a configuration, since the plurality of heat transfer tubes 3 are connected to the common inlet chamber 2 and outlet chamber 4, respectively, the inlet pressure and the outlet pressure of each heat transfer tube 3 are the same. The quantity of steam is decided so that it becomes.
That is, the pressure loss of the flow in each heat transfer tube 3 is the same.

On the other hand, the air flows in from below the lowermost heat transfer tube 3 and is heated by the lower heat transfer tube 3 and flows upward while the temperature rises. Becomes smaller. Therefore, the condensation capacity of each heat transfer tube 3 is largest at the lowest stage where the temperature difference between steam and air is largest,
It decreases as going upward.

[0006] Since the pressure loss of the flow in the heat transfer tube 3 increases as the flow rate of the steam flowing in increases, the amount of steam sufficient to condense into the heat transfer tubes 3 increases the pressure loss of the lower heat transfer tube 3. And the pressure cannot be balanced. For this reason, the heat transfer tubes 3 above and below the pressure balance are completely condensed on the way, and as shown in FIG. 3, the condensate flows out to the outlet chamber 4 while flowing through the bottom of the tubes. 3
The non-condensable gas 20 stays in the upper part of the pipe up to the outlet.

FIG. 4 is a diagram showing the relationship between the position of the heat transfer tube 3 described above and the position where the condensation is completed in each heat transfer tube at the longitudinal position. As shown in FIG. Condensation of the heat transfer tube 3 is completed on the upstream side of the tube.
In such a state, the non-condensable gas 2 in the heat transfer tube 3
Since condensation does not occur in the portion where 0 has accumulated, the heat transfer surface of this portion is ineffective, and the effective heat transfer area is insufficient as a whole, resulting in an insufficient amount of condensation.

[0008]

As described above, in the conventional air-cooled condenser, air flows in from the lowermost heat transfer tube side, flows upward, and cools the heat transfer tubes sequentially from the bottom through the upper heat transfer tubes. However, the air is heated, so that the temperature of the air rises as it goes upward, and the temperature difference between the steam and the air becomes smaller as the heat transfer tubes rise. Therefore, the condensation capacity of the upper and lower heat transfer tubes decreases as the lowest stage, where the temperature difference between steam and air is the largest, goes up at the maximum. On the upstream side, the condensate flows on the bottom surface of the heat transfer tube downstream of the condensation completion position in the tube, non-condensable gas accumulates in the upper space inside the tube, the heat transfer surface in this part becomes invalid, and the effective transfer The heat area was insufficient, and the amount of condensation was insufficient.

Therefore, the present invention changes the steam inflow of the heat transfer tubes arranged above and below the air-cooled condenser in the upper and lower stages, respectively.
Provide an air-cooled condenser that equalizes the pressure loss from the inlet side to the outlet side of steam in each heat transfer tube, eliminates the accumulation of non-condensable gas in each heat transfer tube, and effectively acts the heat transfer area. The object of the present invention is to prevent the shortage of the amount of condensation from occurring.

[0010]

The present invention provides the following means (1) and (2) in order to solve the above-mentioned problems.

(1) In an air-cooled condenser in which a plurality of heat transfer tubes for guiding steam are arranged inside and below the heat transfer tubes, air flows around the heat transfer tubes to cool and condense the steam in the heat transfer tubes. And an orifice at the steam inlet
The orifice is an air-cooled condenser characterized in that the orifice is gradually narrowed toward the top.

(2) In an air-cooled condenser in which a plurality of heat transfer tubes for guiding steam inside are arranged vertically and air flows around the heat transfer tubes to cool and condense the steam in the heat transfer tubes. An air-cooled condenser characterized in that the diameter gradually decreases as it goes up.

In (1) of the present invention, an orifice is provided at the steam inlet of the heat transfer tube, and the degree of throttle of the orifice at each stage is such that the steam inflow at which the condensation is completed at the steam outlet of the heat transfer tube is completed. Set so that That is, the degree of restriction of the orifice is changed for each stage so that the pressure loss from the inlet to the outlet of the heat transfer tube when condensation has just completed at the outlet of the heat transfer tube is equal in all the heat transfer tubes. Therefore, by adding pressure loss at each such orifice,
Since the pressure loss is balanced when a sufficient amount of steam flows into each heat transfer tube, the condensation is completed in the middle of the inlet and outlet in each heat transfer tube, and then the flow There is no accumulation of condensed gas, and the heat transfer surfaces of all the heat transfer tubes work effectively, and the amount of condensate does not become insufficient.

In (2) of the present invention, the inner diameter of each heat transfer tube is set so that the pressure loss from the inlet to the outlet of the heat transfer tube when condensation is completed at the outlet of the heat transfer tube is equal in all the heat transfer tubes. The smaller the value is, the lower the setting goes from bottom to top. By appropriately setting the inner diameter of the heat transfer tubes in this manner, the pressure loss is balanced in a state where the amount of steam flowing into each heat transfer tube matches the condensing capacity. There is no accumulation of condensed gas, all the heat transfer areas work effectively, and there is no shortage of condensed gas.

[0015]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a configuration diagram of the air-cooled condenser according to the first embodiment of the present invention. In the figure, reference numerals 1 to 10 have the same functions as those of the conventional configuration shown in FIG. 3 and thus are omitted and will be referred to as they are. I do.

In FIG. 1, reference numeral 11 denotes an orifice;
No orifice is provided in the bottom heat transfer tube 3 (A),
(B), (C), and (D), the degree of aperture is narrowed toward the top. Air is the bottom heat transfer tube 3 (A)
From (B), (C), (D) to flow upward sequentially,
The air around the upper heat transfer tube is heated, and the temperature difference between steam and air becomes smaller. Accordingly, the condensing capacity is higher in the lower stage and decreases in the upper stage.

The degree of restriction of the orifice 11 depends on the heat transfer tube 3
The degree of throttling is changed for each stage so that the pressure loss from the inlet to the outlet of the heat transfer tube 3 when condensation is completed at the outlet of the heat transfer tube 3 becomes equal in all the heat transfer tubes 3.

Accordingly, in the lowermost heat transfer tube 3 (A), steam flows in from the inlet side, heats the surrounding air, condenses as it flows downstream in the tube, and completes the condensation at the outlet side. The diameter is set so as to be the amount. Heat transfer tube 3
As the condensation capacity decreases as going to the upper stages (B), (C), and (D), the orifice 11 also sequentially narrows the orifice 11 so as to limit the steam inflow amount by that amount. ), (C) and (D), the steam inflow amount is such that the steam flowing from the inlet side is completely condensed at the outlet side.

Therefore, in the first embodiment, by adding such pressure loss of the orifice,
Since the pressure loss is balanced in a state where the amount of steam corresponding to the condensing capacity flows into each heat transfer tube 3, non-condensable gas does not accumulate in the heat transfer tube 3, and all the heat transfer surfaces function effectively. Thus, there is no shortage of condensation. The configuration and operation other than those described above are the same as those of the conventional example, and thus description thereof is omitted.

FIG. 2 is a configuration diagram of an air-cooled condenser according to a second embodiment of the present invention. In the figure, reference numerals 1, 2, 4
10 to 10 have the same functions as those of the first embodiment, and a description thereof will not be repeated.
Heat transfer tubes denoted by reference numerals 34 to 34 will be described below.

In FIG. 2, heat transfer tubes 31, 32, 33,
Numerals 34 have different inner diameters, 31 being the largest, and 32, 33, 34, with the upper heat transfer tubes having smaller diameters as they go upward. The smaller the inner diameter of the heat transfer tube, the greater the pressure loss at the same flow rate. Heat transfer tubes 31, 32,
The inner diameter of each of the pipes 33 and 34 is set so that the pressure loss from the inlet to the outlet of the heat transfer pipe when the condensation is completed at the outlet of the heat transfer pipe is equalized. It is changed for each stage.

In the second embodiment of the above configuration, by appropriately selecting the inner diameter of the heat transfer tubes in this manner, the amount of steam flowing into each of the heat transfer tubes 31, 32, 33, and 34 matches the condensing capacity. Since the pressure loss is balanced in the state, the non-condensable gas does not accumulate in the heat transfer tube, all the heat transfer surfaces work effectively, and the condensed amount does not become insufficient. Note that the configuration and operation other than those described above are the same as those of the first embodiment, and a description thereof will be omitted.

[0023]

According to the first aspect of the present invention, an air-cooled condenser is provided in which a plurality of heat transfer tubes for guiding steam are arranged inside and below, and air flows around the heat transfer tubes to cool and condense the steam in the heat transfer tubes. Wherein an orifice is provided at a steam inlet of each of the heat transfer tubes, and the orifice is gradually narrowed toward an upper stage. By adding a pressure loss to each heat transfer tube with the orifice of such an air-cooled condenser, the pressure loss balances with the amount of steam flowing into each heat transfer tube in a manner commensurate with the condensation capacity. Does not accumulate, all the heat transfer surfaces function effectively, and insufficient condensation does not occur.

Further, (2) of the present invention is characterized in that, in the air-cooled condenser, the diameter of each heat transfer tube is gradually reduced as going upward. In this way, by selecting the inner diameter of each heat transfer tube so that the pressure loss from the heat transfer tube inlet to the outlet when the condensation is completed at the outlet of the heat transfer tube is equal for all the heat transfer tubes, The pressure loss is balanced in a state where the amount of steam corresponding to the condensing capacity flows, and the same effect as the above (1) can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an air-cooled condenser according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an air-cooled condenser according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional air-cooled condenser.

FIG. 4 is a view showing a position where condensation of a heat transfer tube in each stage is completed in a conventional air-cooled condenser.

[Description of Signs] 1 inlet pipe 2 inlet chamber 3 heat transfer pipe 4 outlet chamber 5 outlet pipe 6 vent pipe 7 blower 8 motor 9 blower duct 11 orifice 31 to 34 heat transfer pipe

Claims (2)

[Claims] 1. An air-cooled condenser, in which a plurality of heat transfer tubes for introducing steam into the inside of the heat transfer tube are arranged vertically and air flows around the heat transfer tubes to cool and condense the steam in the heat transfer tubes. An air-cooled condenser characterized in that an orifice is provided at the steam inlet and the orifice is gradually narrowed toward the top. 2. An air-cooled condenser, in which a plurality of heat transfer tubes for guiding steam inside are arranged vertically and air flows around the heat transfer tubes to cool and condense the steam in the heat transfer tubes. Is an air-cooled condenser characterized by decreasing in size as it goes up.