A two-phase flow structure for preventing low-pressure evaporator of a waste heat boiler of a combustion engine

Abstract

The utility model discloses a kind of for preventing gas turbine waste heat boiler low-pressure evaporator two-phase flow structure, including evaporator finned tube module, evaporator finned tube module is composed of multiple rows staggered arrangement evaporator finned tube group, evaporator finned tube module is arranged in flue, the upper and lower ends of evaporator finned tube module in flue are respectively provided with side wall smoke baffle, two side module smoke baffle is fixedly installed on the end of evaporator finned tube module two sides, two side module smoke baffle is covered by folding plate outside.This utility model increases the side wall smoke baffle between evaporator finned tube module and flue side wall board and increases two side module smoke baffle and vertical smoke baffle on evaporator finned tube module, can guarantee the gap between evaporator finned tube even, and there is no flue gas corridor situation everywhere, when unit operation, evaporator finned tube is heated even can effectively avoid the situation that evaporator finned tube occurs two-phase flow corrosion, greatly increase the service life of evaporator finned tube.

Description

Technical Field

[0001] This utility model relates to the technical field of gas turbine waste heat boiler structure, and in particular to a structure for preventing two-phase flow in the low-pressure evaporator of a gas turbine waste heat boiler. Background Technology

[0002] In order to fully utilize the waste heat from the gas turbine exhaust in combined cycle gas turbine units, waste heat boilers typically employ a multi-stage system to absorb the waste heat from the gas turbine exhaust in stages. The low-pressure evaporator of the waste heat boiler is generally located in the tail flue. The pressure at the low-pressure evaporator of the gas turbine waste heat boiler is generally 0.3~0.6 MPa. Within this pressure range, the tubes on the heating surface of the low-pressure evaporator are highly susceptible to two-phase flow corrosion, especially the tubes located on both sides of the evaporator's heating surface.

[0003] The headers of gas turbine waste heat boilers are typically located within the flue, and end caps must be installed at both ends. This prevents the placement of heat transfer tubes within a certain range at both ends, with the distance from the heat transfer tubes to the header ends generally around 60mm. Furthermore, the headers within the flue must account for expansion, typically requiring a 50mm clearance between the header ends and the flue sidewalls. Therefore, the distance between the heat transfer tubes and the sidewalls is generally around 110mm, but the spacing between the evaporator finned tubes is typically only around 20mm. Due to the modular design of the gas turbine's heat transfer surfaces, it's impossible to install baffles between each tube and the sidewall on-site, resulting in flue gas corridors on both sides. This causes the flue gas velocity on both sides of the module to be significantly higher than the flue gas velocity between the heat transfer surfaces within the module. The heat exchange between the evaporator finned tubes and the flue gas on both sides exceeds the designed heat exchange capacity. The large amount of heat absorbed by the evaporator finned tubes on both sides leads to the formation of a large amount of steam-water mixture inside the tubes, causing a sharp increase in the working fluid velocity and resulting in two-phase flow corrosion. This significantly reduces the service life of the evaporator finned tubes and may even lead to tube rupture, affecting the safe operation of the boiler. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model designs a structure for preventing two-phase flow in the low-pressure evaporator of a gas turbine waste heat boiler.

[0005] The present invention adopts the following technical solution: A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler includes an evaporator header and an evaporator finned tube module connected to the evaporator header. The evaporator finned tube module is composed of multiple rows of staggered evaporator finned tubes. The evaporator finned tube module is arranged in a flue. Side wall smoke baffles are respectively provided on both the upper and lower ends of the evaporator finned tube module in the flue. Side module smoke baffles are fixedly installed on both ends of the evaporator finned tube module. The side module smoke baffles are covered by folded plates.

[0006] The factory installs a single, continuous smoke baffle on each side of the module's hot surface to prevent direct contact between the evaporator fins and the flue gas, thus reducing the heat absorption of the evaporator fins. On-site, after the module is installed, a single, continuous sidewall smoke baffle is installed at each of the four corners of the module's hot surface onto the flue sidewall to reduce the flow of flue gas on both sides of the module's hot surface.

[0007] Preferably, a vertical smoke baffle is fixedly installed on the inner side of the smoke baffles on both sides of the module at the larger gap between each row of evaporator fin tubes and the smoke baffles on both sides of the module. The evaporator fin tubes are arranged in a staggered manner, and a vertical smoke baffle is installed in the factory at the larger gap between the evaporator fin tubes and the smoke baffles on both sides of the module to ensure that the spacing between all evaporator fin tubes is uniform.

[0008] Preferably, the side wall smoke baffle is fixedly installed on the side wall of the flue inside the flue.

[0009] Preferably, the installation position of the side wall smoke baffle is consistent with the position of the upper and lower ends of the evaporator finned tube module.

[0010] Preferably, the height of the smoke baffles on both sides of the module is the same as the height of the evaporator finned tube module.

[0011] Preferably, the installation width of the smoke baffles on both sides of the module is the same as the width of the evaporator finned tube module.

[0012] Preferably, the sidewall smoke baffle is fixed to the flue sidewall by welding.

[0013] Preferably, the vertical smoke baffle is welded and fixed to the inner side of the smoke baffle of the two side modules.

[0014] Preferably, the smoke baffles and folding plates on both sides are connected to the evaporator finned tubes by U-bolts.

[0015] The beneficial effects of this utility model are as follows: This utility model adds side wall smoke baffles to the evaporator finned tube module and the flue side wall plate, as well as side module smoke baffles and vertical smoke baffles on the evaporator finned tube module. This can ensure that the gap between the evaporator finned tubes is uniform and there is no flue gas corridor. When the unit is running, the evaporator finned tubes are heated evenly, which can effectively avoid the two-phase flow corrosion of the evaporator finned tubes and greatly increase the service life of the evaporator finned tubes. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 yes Figure 1 Side view; Figure 3 yes Figure 1A magnified view of part I.

[0017] In the diagram: 1. Evaporator header, 2. Evaporator finned tube, 3. Flue side wall panel, 4. Side wall smoke baffle, 5. Side module smoke baffles, 6. Vertical smoke baffle, 7. Folded plate, 8. U-bolt. Detailed Implementation

[0018] The technical solution of this utility model will be further described in detail below through specific embodiments and with reference to the accompanying drawings: Example: Figures 1-3 As shown, a structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler includes an evaporator header 1, an evaporator finned tube 2, a flue side wall plate 3, a side wall smoke baffle 4, two side module smoke baffles 5 and a vertical smoke baffle 6, as well as a folding plate 7 and a U-bolt 8 for fixing the two side module smoke baffles 5.

[0019] During module assembly in the factory, the vertical smoke baffle 6 is first fixed to the two side module smoke baffles 5 by welding. The two side module smoke baffles 5 are then fixed to the evaporator finned tubes 2 by folding plates 7 and U-bolts 8. The connection of the U-bolts 8 can accommodate the expansion difference between the evaporator finned tubes 2 and the two side module smoke baffles 5. Furthermore, the addition of the two side module smoke baffles 5 and the vertical smoke baffle 6 ensures that the gap between the evaporator finned tubes 2 is uniform and there is no flue gas corridor.

[0020] After the on-site modules are installed, the side wall smoke baffles 4 are welded and fixed to the flue side wall plate 3, and are tightly attached to the evaporator fin tubes 2 at the corners, without any connection between them. Adding side wall smoke baffles 4 at the four corners of the hot surface module can greatly reduce the flue gas flow rate in the gaps on both sides of the hot surface module.

[0021] The embodiments described above are merely preferred solutions of this utility model and are not intended to limit this utility model in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler, comprising an evaporator header and an evaporator finned tube module connected to the evaporator header, the evaporator finned tube module being composed of multiple rows of staggered evaporator finned tubes, the evaporator finned tube module being arranged within the flue, characterized in that... Side wall smoke baffles are respectively installed on both the upper and lower ends of the evaporator finned tube module inside the flue. Side module smoke baffles are fixedly installed on both ends of the evaporator finned tube module, and the side module smoke baffles are covered by folded plates.

2. The structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler according to claim 1, characterized in that, A vertical smoke baffle is fixedly installed on the inner side of the smoke baffle of the two side modules at the larger gap between each row of evaporator fin tubes and the smoke baffle of the two side modules.

3. A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler according to claim 1, characterized in that, The side wall smoke baffle is fixedly installed on the side wall of the flue inside the flue.

4. A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler according to claim 1, characterized in that, The installation position of the side wall smoke baffle is consistent with the position of the upper and lower ends of the evaporator finned tube module.

5. A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler according to claim 1, characterized in that, The height of the smoke baffles on both sides of the module is the same as the height of the evaporator finned tube module.

6. A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler according to claim 1, characterized in that, The installation width of the smoke baffles on both sides of the module is the same as the width of the evaporator finned tube module.

7. A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler according to claim 1, characterized in that, The side wall smoke baffle is fixed to the flue side wall by welding.

8. A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler according to claim 2, characterized in that, The vertical smoke baffle is welded and fixed to the inner side of the smoke baffle of the two side modules.

9. A structure for preventing two-phase flow in a low-pressure evaporator of a gas turbine waste heat boiler according to claim 1, characterized in that, The smoke baffles and folding plates on both sides are connected to the evaporator finned tubes by U-bolts.

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