JPS58164901A - Exhaust-heat recovery heat exchanger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat recovery heat exchange device that promotes higher efficiency and higher perturbation rate in special-number nibrants used in combined cycle power plants and the like.

A combined cycle is a power generation system that increases plant efficiency by combining a gas turbine and a steam turbine (2), and among these, the N-type combined cycle is a cycle that achieves exhaust heat recovery. The exhaust heat recovery heat exchanger, which is the main component of the exhaust heat concave combined cycle power generation system, is an internal exchanger that heats water using the gas turbine's island hot exhaust (2) to generate steam.

Figure 1 shows a typical power generation plant. In Figure 1, the power plant consists of a combination of a gas turbine 1, a steam turbine 2, and a generator 3 driven by them. .

The temperature of the exhaust gas after the work of the gas turbine 1 is normally high, about 500° C. to 600° C., and it is extremely uneconomical to discard this as it is as exhaust gas.

Therefore, the high temperature exhaust gas of the gas turbine 1 is transferred to the exhaust heat recovery heat exchanger 4.
0 and exchanges heat with condensate sent from the condensate disk 5 of the steam turbine 2.

The exhaust heat recovery heat exchanger 4 is provided with an evaporator 7 consisting of a large number of heat transfer tubes 6 and an economizer 8.

One end of the heat transfer t6 of the evaporator 7 communicates with the bottom of the steam drum IO via the pump 9, and the other end communicates with the bottom of the steam drum IO.
The two upper steam chambers C are in communication. Also economizer 8
One end of the heat transfer tube 6 communicates with the vicinity of the bottom of the steam drum IO, and the other end communicates with the condenser 5N through a water supply pipe 111 and a water supply control valve I2 and a water supply pump 13. Note that the steam in the steam drum IO is guided through a steam pipe 14 and sent to the steam turbine 2.

In the exhaust heat recovery type combined cycle power generation plant configured as described above, the plant is generally started by closing all the water supply control valves 12 and starting the gas turbine 1. When the gas turbine 1 is started 52, the high temperature exhaust gas of the gas turbine 1 flows into the waste heat collecting exchanger 4t' as shown by the arrow.

nothing. At this time, the exhaust heat is lil! l The heat exchanger tube 6 (2) of the economizer 8 of the heat absorption exchanger 4 is not flowing because the feed water control valve 12 is in a fully closed state. When high temperature exhaust gas flows there from the gas turbine 1, the The feed water in the heat transfer tubes 6 exchanges heat with the high-temperature exhaust gas, causing evaporation of the feed water and increasing the internal pressure of the heat transfer tubes 6.Then, the steam generated in the heat transfer tubes 6 is generated due to the difference in specific gravity from the feed water. The heat is accumulated above the heat transfer t6 of the economizer 8. At this time, since the steam drum IO is located at a position 12 below the heat transfer tube 6 of the economizer 8,
The feed water is pushed out to the steam drum IO, and there is no feed water in the heat exchanger tubes 6 of the economizer 8, resulting in an overheated state.

' When the water supply control valve 12 is opened, the low-temperature water supply flows into the heat transfer tube t6 of the economizer 8, and the heat transfer tube 6
The water flows at high speed and collides with the U-bend, giving a large impact. In the worst case, the F'i heat exchanger tube 6 may be damaged or the water supply may leak or cause an accident.

□ Also, even if the water supply control valve 12 is opened and water flows, the water is used to fill the space in the heat transfer tube 6H, and is not immediately transferred to level 4 of the steam drum 10, but instead flows between the water supply control valve 12 and the steam drum. Hunting occurs due to the control of the lO level t, causing poor control of the steam drum lO at startup.

An object of the present invention is to prevent the economizer heat exchanger tubes from overheating without water supply when starting a gas turbine, and to prevent malfunctions in level control of the steam drum from occurring, thereby providing a highly reliable waste heat recovery heat exchange system. is to provide.

In order to achieve the above objects, the present invention includes an exchanger through which high-temperature exhaust gas is introduced, an economizer and an evaporator comprising a large number of heat transfer tubes disposed in the exchanger, and an economizer that exchanges heat with the exhaust gas. The steam drum, into which the heated feed water is introduced and the steam produced by exchanging heat with the exhaust gas in the evaporator and then recovered again, is biased A, and the transmission of the feed water w1 nieronomyp between the economizer and the steam drum is This invention relates to an exhaust heat recovery mature exchanger system fItJ, characterized in that it is provided with a resistance part that suppresses the flow of water supplied to the steam drum caused by abnormal pressure in the heat pipe.
Embodiment 1 shown in FIG. 1 and FIG. 3 will be described. Since the same reference numerals in FIGS. 2 and 3 as in FIG. 1 indicate the same parts, the explanation thereof will be omitted. In the first unit of the present invention, the heat transfer tube 6 of the economizer 8 is connected to the bottom of the steam drum 10 (-1) due to the abnormal pressure inside the heat transfer t6. In the embodiment shown in drawing 0 in which the resistor part 15 is provided, the resistor part 15 is connected to the water supply pipe 16 which connects the steam drum lO and the heat exchanger tube 6 of the economizer 8.
5 is shown in the example. This loop tube 15F
i. The water supply pipe 11 that leads the water supply to the economizer 8 is raised to a height equal to or higher than the height 62, and the structure is such that the water supply 1:water head of the heat exchanger tube 6 of the economizer 8 is given.

Next, the operation of the exhaust heat recovery heat exchange device according to the second aspect of the present invention will be explained. At the start-up time 82 of the power generation plant shown in FIG. 2, the feed water control valve 12 is in a fully closed state, so no feed water flows into the heat transfer tubes 6 of the economizer 8. However, due to the startup of the gas turbine 1, high temperature exhaust gas is transferred to the exchanger 4.
+2 flows in and exchanges heat with the feed water inside the heat transfer tube 60 of the economizer 8, and the feed water of the heat transfer t6 evaporates and the internal pressure rises rapidly.

At this time, due to the difference in specific gravity between the steam and the feed water, the steam is drawn above the heat transfer tube 6 (although it accumulates in two places, inside the tube 1).
In order to push it out to 0, the internal pressure of the heat transfer tube 6 is
The pressure C must be higher than the head H given by 15.

There is a time delay until the internal pressure of the heat exchanger tube 6 rises to a pressure equivalent to the water head H given by the loop tube 15. During this time delay, the C2 water supply control valve 12 is opened, allowing the supply water to flow through the heat exchanger tubes 60 of the economizer 8. Therefore, the water supply inside the heat exchanger tube 6 does not run out, and the impact on the U-bend portion of the heat exchanger tube 65 due to the overheated and overheated heat exchanger tube 65 and the low-temperature supply water flowing into the heat exchanger tube 65 is effective.
Can speak and kneel. In addition, since the C supply water control valve 12 closes before the supply water in the heat pipe 6 of the economizer 8 runs out, the supply water supplied to the economizer 8 is ``'i'', which is the level 4 of the C2i driver 410. However, the level control of the steam drum 10 during startup is not affected. In the other embodiment shown in FIG. 4 (2), the loop tube 15 is formed in a loop with a large detour, and it goes without saying that the same effect as in the case of FIG. 3 can be obtained.

In the embodiment shown in Figure 2, the resistance section 15 is realized by using a loop pipe, but for example, one nitrogen rift may be installed in the middle of the water supply pipe 16 between the heat exchanger tube 6 of the economizer 8 and the steam drum. Under normal conditions, the resistance is low, but when abnormal pressure occurs inside the heat transfer tubes 6 of the economizer 8, the feed water in the heat transfer tubes 6 rapidly flows to the steam drum IO due to the abnormal pressure. It is also possible to design C2 so that the flow becomes large and the flow is suppressed.

However, in the case of an orifice, it is necessary to design it so that when the pressure in the heat exchanger tube 6 of the economizer 8 is normal (2) the resistance to the flow of water 52 is small.

As described above, according to the '2F invention 62, water supply to the steam drum caused by abnormal pressure in the heat exchanger tubes occurs in the middle of the water supply pipe between the heat exchanger tubes of the economizer and the steam (°1.i, ram). By providing a resistance part that suppresses the flow of water, there is no possibility of overheating when there is no water supply in the heat exchanger tubes, and there is no possibility of poor level control of the steam drum.
A highly reliable exhaust heat recovery heat exchange device can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing a combined cycle power generation plant having a conventional waste heat recovery heat exchanger, and Fig. 2 shows an unbound cycle employing the waste heat (b) convergence exchange device according to the present invention by Hibiki. System diagram, FIG. 3 is a structural diagram showing one embodiment of the exhaust heat recovery heat exchange device according to the present invention≦2. l...Gas turbine 2...Steam turbine 3...
- Generator 4...Exhaust heat recovery heat exchanger 5...
Condensate width 6...Heat transfer tube 7...Evaporation width
8...Economizer 9...Pump l
O...Steam drum 11.16...Water supply pipe 12
...Water supply control valve 13...Water supply pump 15...
・Resistance part (loop pipe) H... Water head 4...
・Water surface level (To~ 斃 ト＼OGo ト笥'-o ト Size procedure correction method 1) 1. Display of the case Japanese Patent Application No. 56-190553 2 Name of the invention Waste heat recovery heat exchange device 3 Relationship with the amended ministry case Patent applicant (307) Tokyo Shibaura Electric Co., Ltd. 4 Agent Address: 105 Tokyo 1-9-10 Toranomon, Minato-ku Minato-ku Densei Pill 5, Date of amendment order: April 26, 1982 (shipment date) 6. Subject of amendment. 1. Column for a brief explanation of the drawings - Insert the statement [Fig. 4 is a structural diagram showing another embodiment of the present invention] between the words "is" and "is". That's all □・,,′・ 11・

Claims (1)

[Scope of Claims] (1) An exhaust heat recovery heat exchanger to which high-temperature exhaust gas is introduced, an economizer and an evaporator consisting of a large number of heat transfer tubes arranged in this exchange path, and an economizer and an evaporator to which exhaust gas is introduced. A water supply pipe between the economizer and the steam drum, comprising a steam drum through which feed water heated by heat exchange is guided and from which the steam produced by heat exchange with exhaust gas in an evaporator is recovered, and An exhaust heat recovery heat exchange device characterized in that a resistance part is provided to suppress the flow of water to the steam drum caused by abnormal pressure in the heat transfer tube of the economizer (2) The resistance part is connected to the water supply pipe leading to the economizer 6. The exhaust heat recovery heat exchange device (8) described in item 1 of the scope of the request, characterized in that the fc is formed by a loop pipe set aside to a height higher than that, and the resistance part is an economizer and a steam drum. The exhaust heat recovery heat exchange device according to item 1 of the claimed scope of the patent, characterized in that the orifice is formed by an orifice provided in the middle of a water supply pipe between the