JPS586302A - Waste heat recovering 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 an exhaust heat recovery heat exchanger used in a combined cycle power generation plant, etc., and in particular to an exhaust heat recovery heat exchanger that promotes high efficiency and high operation rate of the plant. Regarding structural improvements.

A combined cycle is a power generation system that increases plant efficiency by combining a star pint steam turbine, and a typical combined cycle is called the exhaust heat recovery type. An exhaust heat recovery heat exchanger, which is a main component of an exhaust heat recovery type combined cycle power plant, acts as a type of heat exchanger that heats water and generates steam using the high temperature exhaust gas of a gas turbine. An example of a conventional exhaust heat recovery heat exchanger will be described below with reference to FIG.

High-pressure and high-temperature combustion gas produced by a combustor (not shown) flows into the gas turbine 1 and is rotated at high speed, thereby reducing the pressure and temperature and exhausting the gas. However, since the temperature of this exhaust gas is normally a high temperature of 500 to 600°C, it is extremely uneconomical to dispose of it as waste gas. An exhaust heat recovery heat exchanger 2 is provided based on this idea, and the high-temperature exhaust gas from one gas turbine is sent to the exhaust heat recovery heat exchanger 2 through an inlet duct 3.

The exhaust heat recovery heat exchanger 2 is a device that has a large number of heat transfer tubes and performs heat exchange between water and exhaust gas by forced convection heat transfer.

The exhaust gas that has entered the exhaust heat recovery heat exchanger 2 flows upward, passes through the evaporator 4 and the economizer 5, and exits from the outlet duct 7 to a chimney (not shown). Here, an evaporator 4 and an economizer 5Vi.

It is composed of a large number of heat transfer tubes 6, through which steam and water flow. One end of the heat exchanger tube 60 of the economizer 5 is connected to the heat exchanger water supply pipe 8, and the oil tube end is connected to the lower part of the steam drum 9. Also, the heat transfer tube 6 of the evaporator 4
Both pipe ends are attached to the drum 9. Further, a main steam pipe 14 is connected to the upper end of the steam drum 9, and the main steam pipe 14 is led to a steam turbine 12. Also,
A condenser 1 is installed in series with the steam turbine 12. In addition, a 27-piece collective duct is shown in b.

In the above configuration, the exhaust steam of the steam turbine 12 is converted into condensate in the condenser 11 and is forcedly sent to the economizer 5 through the water supply pipe 8 by the water supply 7ynzo 13. economizer 5
The heated feed water enters the lower part ICa of the steam drum 9.

Steam 19 The canned water in the ram 9 is transferred from the bottom of the drum to the ponder 1.
0 is sent to the evaporator 4, evaporated in the heat exchanger tube to become steam, and returned to the upper part of the steam drum 9 again.

Steam in the steam drum is extracted from the upper part of the drum, introduced into the steam turbine through the main steam pipe 14, and returned to the condenser 11.
flows into.

It has been confirmed that in the above-mentioned waste heat recovery type combine harvester (parcycle) power generation plant, the plant thermal efficiency is increased by several percent compared to the conventional plant because the gas turbine exhaust gas is effectively used.

Figure 2 is a three-dimensional perspective view of the (H structure) of the exhaust heat recovery heat exchanger J (Y heat exchanger).The exhaust heat recovery heat exchanger S is usually a very large structure, so it is difficult to manufacture. For ease of transportation and installation, it is common to have a structure that is divided into multiple parts.In the example in Figure 2, the heat exchanger for one gas turbine exhaust is divided into two parts, A and B. The steam generation capacity is
The gas turbine exhaust gas is evenly distributed to two divided heat exchangers A and B, and the flow rate of the gas turbine exhaust gas is divided into two by a special Y duct 3.

By the way, in this type of exhaust heat recovery heat exchanger, 2
If one side of the divided unit becomes inoperable due to an accident, the entire unit, including the gas turbine and steam turbine, must be stopped in order for workers to enter the interior for inspection or repair. Zorant V will remain idle until it is completed.

Moreover, once a plant is stopped, it takes a lot of effort and time to restart it. Therefore, the operating rate of the plant decreases significantly.

This invention was made in view of the above, and aims to provide an exhaust heat recovery heat exchanger that can promote high efficiency and operation rate of a plant and can be operated according to usage conditions. .

Hereinafter, this invention will be explained in 5-5 with reference to the drawings. explain.

That is, FIG. 3 is a perspective view showing an embodiment of the present invention, in which a modified Y duct 3 is provided at the exhaust inlet of the stub bin 71', and is connected to the divided end of the Y duct 30. Then, a partition 21, for example a linear valve, is attached. Furthermore, several gate valves 21, for example linear valves, are provided in the heat exchanger bodies 2 of the divided exhaust heat recovery heat exchangers A and B, connected to the outlet ducts 7 connected to each of the heat exchangers 2B.

The linear valve of the gate valve 2 has a sufficiently leaktight structure.

The characteristic of this invention lies in the fact that the gate valve 2 is disposed in the divided heat exchanger body 2 at both the entrance and exit of the heat exchanger body 2B.
By effectively operating this gate valve 2, it becomes possible to increase the operating rate of the plant and reduce L7.

Hereinafter, the operation of the exhaust heat recovery heat exchanger of the present invention configured as described above will be explained.

For example, consider the case where the heat exchanger A side is stopped. At this time, as shown in Fig. 4, the gate valve 21f'i provided at the entrance and exit of the heat exchanger body 2-6 is closed.
Gas turbine exhaust gas flows from the Y duct 3 only into the heat exchanger body 2B. Therefore, normal operation is possible on the heat exchanger B side, but the gate valve 2 completely prevents exhaust gas from flowing into the heat exchangers, allowing workers to freely enter the heat exchanger A. You can come in and out.

Therefore, according to the present invention, each of the divided exhaust heat recovery heat exchangers A and B can be operated or stopped independently. For example, if a heat exchanger AK accident is discovered during normal operation, by immediately reducing the load and closing the gate valve 21, you can wait for the temperature inside the heat exchanger to drop before immediately proceeding to inspection work. I can do it. Therefore, continuous operation can be performed simply by reducing the load on the plant.

In addition, when operating the plant at partial load even outside of an accident, by stopping one side, the flow rate of exhaust gas inside the heat exchanger is maintained, and sufficient forced convection heat transfer is obtained, resulting in high efficiency. be driven.

FIG. 5 is a schematic diagram showing another embodiment of the present invention. In the heat exchanger body 2, two gate valves 21, e.g.
The gas exhaust piping system 22 is equipped with a pump 7'23. When only one gate valve 21 is provided as shown in FIG. 4, a sufficiently leak-tight structure is required, and an expensive left-hand gate valve, such as a butterfly type valve, is required. In the modified example, two inexpensive gate valves 21k that allow some leakage are provided, and the high temperature JJ gas leaking from the LTL butterfly valve 21k near the Y duct 3 is removed from the gas exhaust piping system 22 by the pump 23. to be excluded. The two gate valves 21 have the role of dampers for high-temperature forces in accordance with the heat exchanger A on the stopped side.

In addition, since the exhaust gas passing through the heat exchanger has a low pressure and temperature, an inexpensive gate valve 2 is installed at the heat exchanger outlet tUU.
By installing only one 1k g, it is possible to sufficiently prevent the inflow of exhaust gas.

According to the invention described above, it is possible to improve the efficiency and operation rate of a plant, and to provide an exhaust heat recovery heat exchanger that can be operated according to the usage conditions.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an outline of an exhaust heat recovery type combined cycle power generation gland, Fig. 2 is a perspective view showing an example of a conventional waste heat recovery heat exchanger, and Fig. 3 is an exhaust heat recovery method according to the present invention. A perspective view showing one embodiment of the heat exchanger, FIG.
FIG. 5 is a schematic configuration diagram when the figure is viewed from above, and is a schematic configuration diagram showing another embodiment of the present invention. 2, 2B...heat exchanger body, 3...Y duct at inlet, 21.211L...gate valve, 22...gas exhaust piping system. Applicant's agent Patent attorney Takehiko Suzue 9- Figure 1

Claims (1)

[Claims] (I) A set of exhaust heat having an inlet duct having an outlet divided into a number of shares for one exhaust gas inlet, and a heat exchanger body divided into a number equal to the number of divisions of the duct. 1. An exhaust heat recovery heat exchanger, characterized in that means for opening and closing the gas passages is provided at each inlet/outlet portion of the heat exchanger body. (2) In a set of exhaust heat recovery heat exchangers having an inlet duct having a plurality of divided outlets for one exhaust gas inlet, and a heat exchanger body divided into a number equal to the number of divisions of the duct, A heat exchanger with 11 heat exhaust ports, characterized in that two means for opening and closing the gas passages are arranged in parallel at the inlet of the heat exchanger body, and a gas discharge piping system is attached between the means. .