JPH0565761B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchange device, and particularly to a heat exchange device that can be effectively used as a waste heat recovery boiler and has a simplified piping structure.

With recent changes in the fuel situation, higher power generation efficiency is required in thermal power plants, and one way to achieve this is to construct combined cycle power plants that combine gas turbines and steam turbines. ing. A combined power generation plant first generates electricity using a gas turbine, then recovers the heat from the waste gas discharged from the gas turbine in a waste heat recovery boiler, and uses the steam generated in the boiler to drive a steam turbine to generate electricity. be.

FIG. 1 shows an example of a waste heat recovery boiler. In the figure, exhaust gas G discharged from the gas turbine reaches a waste heat recovery boiler. First, the exhaust gas passes through a superheater 1, then a high-pressure evaporator 2, and then reaches a denitrification device 3, where nitrogen oxides (NOx) contained therein are removed. The exhaust gas G exiting the denitrification device passes through another high-pressure evaporator 4, a high-pressure economizer 5, a low-pressure evaporator 6, and a low-pressure economizer 7 in this order.

The internal fluid on the high pressure side circulates between the high pressure drum (upper drum) 9 and the high pressure evaporator 4 via the downcomer pipe 8, and the generated steam is supplied to the superheater 1. On the other hand, the internal fluid on the low pressure side circulates between the low pressure drum (upper drum) 11 and the low pressure evaporator 6 via the downcomer pipe 10.

As shown in the figure, the plurality of heat transfer tube groups are placed apart from each other in the gas flow, and the load is carried by the bottom support (bottom support) at each lower header.
The structure is such that

In the boiler with the above configuration, each evaporator is composed of a large number of heat exchanger tube panels, and the arrangement of the water supply pipes that supply water to the headers of each panel becomes complicated. Figure 2 shows an example of how water supply pipes are branched. In the figure, a small header 12 is attached to the lower end of a downcomer pipe (the one shown is a high-pressure downcomer pipe 8), and a large number of water supply pipes 14 are connected to this header. The inlet header (lower header) of each heat exchanger tube panel and downcomer pipe 8 are connected. Here, the entire boiler is constructed by consecutively arranging blocks constructed for each group of heat transfer tubes. For example, the header 1 attached to the downcomer pipe 8
2 must be arranged in a space of width L between the installation part of the downcomer pipe 8 and the end face of the evaporator block, as shown in FIG. The connections become complicated as shown. Therefore, it becomes difficult to arrange each water supply pipe, and there is a possibility that the distribution of the internal fluid descending through the downcomer pipe may become unbalanced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to relate to a heat exchange device configured to simplify the arrangement of water supply pipes.

In short, in the present invention, a plurality of groups of heat transfer tubes each consisting of a plurality of panels whose faces are orthogonal to each other in the flow direction of the combustion gas are located in the combustion gas flow, and are connected to the heat transfer tube group from one upper drum via downcomer pipes. In a heat exchange device for water supply, the upper drum and the intermediate header 15 whose axes are parallel to each other are connected by a plurality of downcomer pipes, the upper drum is bottom-supported by one of the intermediate headers 15, and the The intermediate header 15 is connected to a lower header 16 that bottom-supports each of the plurality of heat transfer tube groups located in the flow of combustion gas and is separated from the intermediate header 15, and is connected to each lower header by a plurality of water supply pipes 14. This is a heat exchange device characterized by:

Embodiments of the present invention will be described below with reference to the drawings.

Figure 3 shows the water circulation system on the high pressure side. Two downcomer pipes 8a, 8b are connected to the high-pressure drum 9, and an intermediate header 15 is attached to the lower end of each downcomer pipe 8a, 8b. This intermediate header 1
5 is arranged so as to be substantially parallel to the drum 9, and its total length is approximately equal to that of the upper drum 9, making it large. 16 is a lower header (inlet header) of each heat exchanger tube panel, and water supply pipe 14
connects each of these headers 16 and the intermediate header 15. In this case, since the intermediate header 15 is large-sized, the water supply pipe 14 can be freely connected to the side surface of the intermediate header 15, making attachment of the water supply pipe 14 very easy. In addition, two downcomer pipes 8a, 8b, a drum 9
Since the intermediate header 15 forms a substantially rectangular frame structure, the strength is also higher than that of the piping structure shown in FIG.

FIG. 4 shows an example of the arrangement of the water supply pipes 14.
Normally, the lower header 16 of each heat exchanger tube panel is divided into multiple chambers or pipes along its length, so the number of divided water supply pipes is also required for one lower header. . Therefore, the number of water supply pipes is quite large, but since the intermediate header 15 is long and large, each water supply pipe 14 can be connected to the intermediate header 15 at approximately equal intervals, and the work of installing the water supply pipes is easy. Although the above explanation has been given using the high pressure side piping as an example, the low pressure side has a similar structure.

By implementing this invention, even if a large number of water supply pipes are installed, each water supply pipe can be easily installed, and boiler water passes through an intermediate header with a relatively larger diameter than multiple downcomer pipes. Since water is supplied to each lower header of the heat exchanger tube panel through a plurality of water supply pipes 14, water can be evenly supplied to the plurality of heat exchanger tubes forming the panel, and heat can be evenly and efficiently absorbed from the waste gas. I can do it. This ensures uniform heat transfer and
Heat is absorbed and thermal expansion deformation does not occur between the heat exchanger tube groups, and since they are located apart from each other, thermal expansion deformation does not occur on the drum, intermediate header side, and heat exchanger tube group side. It is also free from the effects of thermal expansion and deformation caused by frequent startup and stoppages.

Furthermore, since the intermediate header can be used as a reinforcing member, the strength of the entire device can be increased.

[Brief explanation of the drawing]

FIG. 1 is a side view of the waste heat recovery boiler, FIG. 2 is a perspective view of a conventional water supply pipe installed state, FIG. 3 is a perspective view of a heat exchange device according to the present invention, and FIG. 4 FIG. 2 is a plan view of the device showing the arrangement of water supply pipes. 8a, 8b... Downpipe, 9... Upper drum, 14
... Water supply pipe, 15 ... Intermediate header, 16 ... Heat exchanger tube panel lower header.

Claims (1)

[Claims] 1 A plurality of groups of heat transfer tubes each consisting of a plurality of panels whose surfaces are perpendicular to the flow direction of the combustion gas are located in the combustion gas flow, and heat is supplied from the upper drum to the heat transfer tube group via the downcomer pipe. In the exchanger, the upper drum and the intermediate header 15 whose axes are parallel to each other are connected by a plurality of downcomer pipes, the upper drum is bottom-supported by the one intermediate header 15, and the intermediate header 15 and a lower header 16 that provides bottom support for each of the plurality of heat transfer tube groups that are spaced apart and located in the combustion gas flow, and the intermediate header 15;
A heat exchange device characterized in that each lower header is connected by a plurality of water supply pipes 14.