Dual-pressure gas turbine waste heat boiler with afterburning function

Abstract

The double-pressure gas turbine waste heat boiler with the afterburning function comprises a boiler flue, and a second high-pressure superheater, a first high-pressure superheater, a high-pressure evaporator, a low-pressure superheater, a high-pressure economizer, a low-pressure evaporator and a low-pressure economizer are sequentially arranged in the boiler flue. An afterburning flue is arranged between the high-pressure superheater II and the high-pressure superheater I in the boiler flue; the high-pressure boiler barrel and the low-pressure boiler barrel are connected through a pipeline, and a shut-off valve and an adjusting valve are arranged in the pipeline. Under the afterburning working condition, the evaporation capacity of a low-pressure system is increased by opening a shut-off valve and an adjusting valve, the problem that the steam yield of the low-pressure system is insufficient is solved, the unit requirement is met by adjusting the opening degree of the adjusting valve and adjusting the steam yield of the low-pressure system, the low-pressure superheater is prevented from being in the dry burning condition, and safe and stable operation of the low-pressure superheater is guaranteed; under the non-afterburning working condition, the shut-off valve and the adjusting valve on the communicating pipeline between the high-pressure boiler barrel and the low-pressure boiler barrel can be closed, and the high-pressure steam yield is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat utilization, in particular to a double compression combustion engine waste heat boiler with supplementary combustion. Background Art

[0002] In the combined cycle, the gas turbine waste heat boiler is used to recover the waste heat in the gas turbine exhaust and generate steam to drive the steam turbine to generate electricity. The steam-water system of the gas turbine waste heat boiler includes heat exchange tube bundles and containers such as steam drum, economizer, evaporator, superheater and header.

[0003] Waste heat boilers can be divided into two types according to whether there is a combustion device or not: waste heat boilers without supplementary combustion and waste heat boilers with supplementary combustion. For waste heat boilers without supplementary combustion, the steam parameters, steam production or power depend on the parameters and flow of the gas turbine exhaust. When the exhaust temperature of the gas turbine is low, but the steam temperature and steam volume of the waste heat boiler are high, the use of waste heat boilers with supplementary combustion becomes a good solution.

[0004] The gas turbine waste heat boiler with supplementary combustion utilizes the residual oxygen in the gas turbine exhaust and increases the flue gas temperature by supplementing natural gas or fuel oil for combustion. This can increase the steam production of the waste heat boiler, improve steam parameters, and improve the variable operating characteristics of the combined cycle.

[0005] However, under the supplementary combustion condition, the increase in flue gas temperature after supplementary combustion causes the heat exchange temperature difference of the upstream high-pressure section heating surface to increase sharply, and the heat absorption of the high-pressure section increases a lot compared to the non-supplementary combustion condition. After the flue gas flows through the upstream high-pressure section heating surface, the flue gas temperature drops to a too low temperature, resulting in too little heat absorption by the downstream low-pressure section evaporation heating surface, which cannot meet the low-pressure steam pressure and evaporation requirements, and then leads to insufficient steam production in the low-pressure system, which cannot meet the unit requirements. The low-pressure superheater may be in a dry burning state, affecting the safe and stable operation of the low-pressure superheater. In severe cases, structural damage accidents may even occur. Utility Model Content

[0006] In order to solve the above technical problems, the utility model designs a double compression combustion engine waste heat boiler with supplementary combustion.

[0007] The utility model adopts the following technical solutions:

[0008] A double compression combustion engine waste heat boiler with supplementary combustion, comprising a boiler flue, wherein a high-pressure superheater 2, a high-pressure superheater 1, a high-pressure evaporator, a low-pressure superheater, a high-pressure economizer, a low-pressure evaporator and a low-pressure economizer are sequentially arranged in the boiler flue;

[0009] A supplementary combustion flue is provided between the high pressure superheater 2 and the high pressure superheater 1 in the boiler flue;

[0010] The low-pressure economizer is connected to a low-pressure drum, the water outlet of the low-pressure drum is connected to the low-pressure evaporator through a downcomer, the low-pressure evaporator is connected to the low-pressure drum through a riser, the steam outlet of the low-pressure drum is connected to the low-pressure superheater, the low-pressure drum is connected to the high-pressure economizer through a pipeline, the high-pressure economizer is connected to the high-pressure drum, the water outlet of the high-pressure drum is connected to the high-pressure evaporator through a downcomer, the high-pressure evaporator is connected to the high-pressure drum through a riser, the steam outlet of the high-pressure drum is connected to the high-pressure superheater 1, and the high-pressure superheater 1 is connected to the high-pressure superheater 2;

[0011] The high-pressure boiler drum is connected to the low-pressure boiler drum by a pipeline, in which a shut-off valve and a regulating valve are arranged.

[0012] Preferably, a flue gas inlet A is provided at the inlet end of the boiler flue, and a chimney is provided at the outlet end of the boiler flue.

[0013] Preferably, the low-pressure economizer is connected to a low-pressure feed water inlet B through a pipeline.

[0014] Preferably, the high-pressure superheater 2 is connected to the high-pressure cylinder C of the steam turbine through a pipeline.

[0015] Preferably, the low-pressure superheater is connected to the low-pressure cylinder D of the steam turbine through a pipeline.

[0016] Preferably, a high-pressure feed water pump E is provided on the pipeline between the low-pressure boiler drum and the high-pressure economizer.

[0017] The beneficial effects of the utility model are as follows: (1) Under the supplementary combustion condition, since a connecting pipe is provided between the high-pressure boiler drum and the low-pressure boiler drum, and a shut-off valve and a regulating valve are provided on the pipe, by opening the shut-off valve and the regulating valve, high-pressure saturated steam is introduced into the low-pressure boiler drum to increase the evaporation amount of the low-pressure system and solve the problem of insufficient steam production of the low-pressure system; (2) Under the supplementary combustion condition, according to the steam volume requirement of the low-pressure superheater outlet, the steam production of the low-pressure system is adjusted by adjusting the opening of the regulating valve to meet the unit requirements; (3) Under the supplementary combustion condition, by ensuring the low-pressure steam production, the low-pressure superheater is prevented from being in a dry burning state, thereby ensuring the safe and stable operation of the low-pressure superheater; (4) Under the non-supplementary combustion condition, the shut-off valve and the regulating valve on the connecting pipe between the high-pressure boiler drum and the low-pressure boiler drum can be closed to ensure the high-pressure steam production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the utility model;

[0019] In the figure: 1. Boiler flue, 11. High-pressure superheater 2, 12. High-pressure superheater 1, 13. High-pressure evaporator, 14. High-pressure economizer, 15. High-pressure boiler drum, 2. Supplementary combustion flue, 21. Low-pressure superheater, 22. Low-pressure evaporator, 23. Low-pressure economizer, 24. Low-pressure boiler drum, 3. Chimney, 31. Shut-off valve, 32. Regulating valve, A. Flue gas inlet, B. Low-pressure feed water inlet, C. Turbine high-pressure cylinder, D. Turbine low-pressure cylinder, E. High-pressure feed water pump. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0021] Example: Figure 1 As shown, a double-compression combustion engine waste heat boiler with supplementary combustion comprises a boiler flue 1, in which a high-pressure superheater 2 11, a high-pressure superheater 1 12, a high-pressure evaporator 13, a low-pressure superheater 21, a high-pressure economizer 14, a low-pressure evaporator 22 and a low-pressure economizer 23 are arranged in sequence. The supplementary combustion flue 2 is arranged between the high-pressure superheater 2 and the high-pressure superheater 1. The low-pressure feed water is connected to the low-pressure economizer through a pipeline, the low-pressure economizer is connected to the low-pressure drum 24, the water outlet of the low-pressure drum is connected to the low-pressure evaporator through a downcomer, the low-pressure evaporator is connected to the low-pressure drum through a riser, the steam outlet of the low-pressure drum is connected to the low-pressure superheater, and the low-pressure superheater is connected to the low-pressure cylinder D of the steam turbine. The water of the low-pressure drum is connected to the high-pressure economizer through the pipeline after passing through the high-pressure feed water pump E, and the high-pressure economizer is connected to the high-pressure drum 15. The water outlet of the high-pressure drum is connected to the high-pressure evaporator through the downcomer, and the high-pressure evaporator is connected to the high-pressure drum through the upcomer. The steam outlet of the high-pressure drum is connected to the high-pressure superheater 1, the high-pressure superheater 1 is connected to the high-pressure superheater 2, and the high-pressure superheater 2 is connected to the high-pressure cylinder C of the steam turbine. The high-pressure drum and the low-pressure drum are connected by a pipeline, and a shut-off valve 31 and a regulating valve 32 are arranged in the pipeline.

[0022] When the double-compression combustion engine waste heat boiler with supplementary combustion is in use, the high-temperature flue gas discharged by the combustion engine enters the boiler flue 1 from the flue gas inlet A, and the heat is transferred to the high-pressure superheater 2 in front of the supplementary combustion flue 2, and the flue gas temperature decreases. After passing through the supplementary combustion flue 2, the flue gas temperature rises, and then passes through the high-pressure superheater 1, high-pressure evaporator and other heating surfaces in turn, and is discharged from the chimney 3.

[0023] Feed water enters from the low-pressure feed water inlet B, enters the low-pressure economizer through the lower header, and enters the low-pressure boiler drum from the outlet header after being heated in the low-pressure economizer. The water in the low-pressure boiler drum enters the low-pressure evaporator through the downcomer, and is heated in the low-pressure evaporator to produce a steam-water mixture. The steam-water mixture enters the low-pressure boiler drum through the riser, and steam and water are separated in the low-pressure boiler drum. The saturated steam after separation enters the low-pressure superheater, and is heated in the low-pressure superheater to form superheated steam, which then enters the low-pressure cylinder D of the steam turbine to perform work. The water in the low-pressure boiler drum passes through the high-pressure feed water pump E and enters the high-pressure economizer through the pipeline. After being heated in the high-pressure economizer, it enters the high-pressure boiler drum from the outlet header. The water in the high-pressure boiler drum enters the high-pressure evaporator through the downcomer, and is heated in the high-pressure evaporator to produce a steam-water mixture. The steam-water mixture enters the high-pressure boiler drum through the riser, and steam and water are separated in the high-pressure boiler drum. The saturated steam after separation enters the inlet header of the high-pressure superheater 1, and is heated in the high-pressure superheater 1 to form superheated steam. It enters the inlet header of the high-pressure superheater 2 through the connecting pipe between the high-pressure superheater 1 and the high-pressure superheater 2, and enters the high-pressure cylinder C of the steam turbine to perform work after being further heated in the high-pressure superheater 2.

[0024] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A double compression combustion engine waste heat boiler with supplementary combustion, comprising a boiler flue, characterized in that: The boiler flue is provided with a high-pressure superheater 2, a high-pressure superheater 1, a high-pressure evaporator, a low-pressure superheater, a high-pressure economizer, a low-pressure evaporator and a low-pressure economizer in sequence; A supplementary combustion flue is provided between the high pressure superheater 2 and the high pressure superheater 1 in the boiler flue; The low-pressure economizer is connected to a low-pressure drum, the water outlet of the low-pressure drum is connected to the low-pressure evaporator through a downcomer, the low-pressure evaporator is connected to the low-pressure drum through a riser, the steam outlet of the low-pressure drum is connected to the low-pressure superheater, the low-pressure drum is connected to the high-pressure economizer through a pipeline, the high-pressure economizer is connected to the high-pressure drum, the water outlet of the high-pressure drum is connected to the high-pressure evaporator through a downcomer, the high-pressure evaporator is connected to the high-pressure drum through a riser, the steam outlet of the high-pressure drum is connected to the high-pressure superheater 1, and the high-pressure superheater 1 is connected to the high-pressure superheater 2; The high-pressure boiler drum is connected to the low-pressure boiler drum by a pipeline, in which a shut-off valve and a regulating valve are arranged.

2. A double compression combustion engine waste heat boiler with supplementary combustion according to claim 1, characterized in that: A flue gas inlet A is arranged at the inlet end of the boiler flue, and a chimney is arranged at the outlet end of the boiler flue.

3. The double compression combustion engine waste heat boiler with supplementary combustion according to claim 1, characterized in that: The low-pressure economizer is connected to a low-pressure feed water inlet B through a pipeline.

4. A double compression combustion engine waste heat boiler with supplementary combustion according to claim 1, characterized in that: The high-pressure superheater 2 is connected to the high-pressure cylinder C of the steam turbine through a pipeline.

5. The double compression combustion engine waste heat boiler with supplementary combustion according to claim 1, characterized in that: The low-pressure superheater is connected to the low-pressure cylinder D of the steam turbine through a pipeline.

6. The double compression combustion engine waste heat boiler with supplementary combustion according to claim 1, characterized in that: A high-pressure feed water pump E is provided on the pipeline between the low-pressure boiler drum and the high-pressure economizer.

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