Dual-pressure gas turbine waste heat boiler sharing economizer

Abstract

The utility model discloses a dual-pressure gas turbine waste heat boiler sharing an economizer, which 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 high-temperature section, a low-pressure evaporator and a high amp are sequentially arranged in the boiler flue; disclosed is a low-pressure shared economizer. High amp; the low-pressure shared economizer is communicated with a boiler water supply inlet and a high amp; the low-pressure shared economizer communicates with the low-pressure boiler barrel through a pipeline, and meanwhile the amp is high; the low-pressure shared economizer further communicates with the high-pressure economizer high-temperature section through a pipeline. According to the dual-pressure waste heat boiler, only one water feeding pump is adopted, steam of two different pressure grades is generated, the system is greatly optimized, and the investment and construction cost is reduced; high amp; the working medium flow circulating in the low-pressure shared economizer is the total flow of a high-pressure system and a low-pressure system, and the vaporization risk of the economizer is reduced; the working medium temperatures of all the hot surfaces are increased step by step, flue gas heat is utilized in a cascade mode, and the efficiency of the waste heat boiler is improved to the maximum degree.

Description

Technical Field

[0001] This utility model relates to the field of waste heat utilization technology, and in particular to a dual-compressor gas turbine waste heat boiler with a shared economizer. Background Technology

[0002] In a combined cycle system, a gas turbine waste heat boiler is used to recover waste heat from the exhaust gas of a gas turbine, generating steam to drive a steam turbine for power generation or for industrial production. The gas turbine waste heat boiler steam-water system includes heat exchange tube bundles and containers such as a steam drum, economizer, evaporator, superheater, and headers.

[0003] To maximize recovery efficiency, gas turbine waste heat boilers utilize the waste heat from the gas turbine exhaust in stages to generate steam at different pressure levels to meet power generation or industrial needs. Each pressure stage of the gas turbine waste heat boiler system has its own relatively independent hot surface and auxiliary equipment, such as superheaters, evaporators, economizers, and feedwater pumps. The working fluid parameters of each hot surface of the boiler are matched to the flue gas temperature parameters stage by stage to avoid the waste of high-grade heat energy.

[0004] In some small-scale combined cycle gas turbine systems, due to industrial steam demand, the waste heat boiler needs to generate two stages of main steam with similar pressures. In this case, the conventional configuration requires two feedwater pumps to supply deoxygenated water to different pressure systems. Because the gas turbine itself has a relatively small power output, the low-pressure system produces less gas, and the required heating surface is less than that of the high-pressure system. The number of transverse tube rows on the low-pressure economizer's heating surface is insufficient to fill the entire furnace width, and vaporization problems easily occur in the low-pressure economizer when the feedwater temperature or gas turbine exhaust parameters change. Furthermore, the boiler requires separate high- and low-pressure feedwater pumps, making the system complex and increasing investment costs. Since the feedwater temperature of both economizers is the same, if the high-pressure and low-pressure economizers are conventionally separated and arranged front and rear in the flue gas direction, the cascade utilization of flue gas heat cannot be achieved, affecting the unit's efficiency.

[0005] In summary, existing dual-pressure waste heat boilers in small gas turbine combined cycle systems still require high and low pressure feedwater pump systems when the main steam pressures of the two stages are not significantly different. This results in a complex and costly system. Furthermore, the low-pressure economizer has a small heat surface area, poor adaptability, and is prone to vaporization due to changes in feedwater or flue gas parameters, posing operational risks. Additionally, the high-pressure and low-pressure economizers are arranged completely separately, making it impossible to achieve cascaded utilization of flue gas heat, leading to low system efficiency. Utility Model Content

[0006] To solve the above-mentioned technical problems, this utility model designs a dual-compressor gas turbine waste heat boiler with a shared economizer.

[0007] The present invention adopts the following technical solution:

[0008] A dual-pressure gas turbine waste heat boiler with a shared economizer includes a boiler flue, in which a high-pressure superheater II, a high-pressure superheater I, a high-pressure evaporator, a low-pressure superheater, a high-temperature section of a high-pressure economizer, a low-pressure evaporator, and a high & low pressure shared economizer are arranged sequentially.

[0009] The high and low pressure shared economizer is connected to the boiler feedwater inlet. The high and low pressure shared economizer is connected to the low pressure boiler drum through a pipeline. The water outlet of the low pressure boiler drum is connected to the low pressure evaporator through a downcomer. The low pressure evaporator is connected to the low pressure boiler drum through a riser. The steam outlet of the low pressure boiler drum is connected to the low pressure superheater. The low pressure superheater is connected to the low pressure steam inlet.

[0010] Meanwhile, the high and low pressure shared economizer is also connected to the high-temperature section of the high-pressure economizer through pipelines. The high-temperature section of the high-pressure economizer is connected to the high-pressure boiler drum through pipelines. The water outlet of the high-pressure boiler drum is connected to the high-pressure evaporator through a downcomer. The high-pressure evaporator is connected to the high-pressure boiler drum through an upcomer. The steam outlet of the high-pressure boiler drum is connected to high-pressure superheater one. High-pressure superheater one is connected to high-pressure superheater two. High-pressure superheater two is connected to the high-pressure steam interface C.

[0011] Preferably, a large differential pressure regulating valve is installed on the connecting pipe between the high and low pressure shared economizer and the low pressure boiler drum.

[0012] Preferably, a regulating valve is installed on the connecting pipe between the high-temperature section of the high-pressure economizer and the pressure boiler drum.

[0013] Preferably, a feedwater pump is installed on the connecting pipe between the boiler feedwater inlet and the high & low pressure shared economizer.

[0014] Preferably, a chimney is connected to the tail end of the boiler flue.

[0015] The beneficial effects of this utility model are: (1) The dual-pressure waste heat boiler uses only one feed water pump to generate steam of two different pressure levels, which greatly optimizes the system and reduces investment and construction costs; (2) The working fluid flow rate in the high and low pressure shared economizer is the total flow rate of the high and low pressure system, which reduces the risk of economizer vaporization; (3) The working fluid temperature of all hot surfaces is gradually increased, realizing the tiered utilization of flue gas heat and maximizing the efficiency of the waste heat boiler. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model;

[0017] In the diagram: 1. Boiler flue, 2. Chimney, 11. High-pressure superheater II, 12. High-pressure superheater I, 13. High-pressure evaporator, 14. High-pressure economizer high-temperature section, 15. High-pressure boiler drum, 21. Low-pressure superheater, 22. Low-pressure evaporator, 23. High & low-pressure shared economizer, 24. Low-pressure boiler drum, 31. Large differential pressure regulating valve, 32. Regulating valve, A. Flue gas inlet, B. Boiler feedwater inlet, C. High-pressure steam interface, D. Low-pressure steam interface, E. Feedwater pump. 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:

[0019] Example: Figure 1 As shown, a dual-pressure gas turbine waste heat boiler with a shared economizer includes a boiler flue 1, in which a high-pressure superheater 21, a high-pressure superheater 12, a high-pressure evaporator 13, a low-pressure superheater 21, a high-pressure economizer high-temperature section 14, a low-pressure evaporator 22, and a high & low pressure shared economizer 23 are arranged in sequence, and a chimney 2 is connected to the tail end of the boiler flue.

[0020] The deoxygenated boiler feedwater enters the high and low pressure shared economizer 23 through feedwater pump E. The high and low pressure shared economizer is connected to the low pressure boiler drum 24 through pipelines and a large differential pressure regulating valve. At the same time, the high and low pressure shared economizer is also connected to the high-temperature section 14 of the high pressure economizer through pipelines. The water outlet of the low pressure boiler drum is connected to the low pressure evaporator 22 through a downcomer. The low pressure evaporator is connected to the low pressure boiler drum through a riser. The steam outlet of the low pressure boiler drum is connected to the low pressure superheater 21. The low pressure superheater is connected to the low pressure steam inlet D.

[0021] Water heated by the high and low pressure shared economizer is connected to the high-temperature section 14 of the high-pressure economizer via pipelines. The high-temperature section of the high-pressure economizer is connected to the high-pressure boiler drum 15 via pipelines and regulating valves. The water outlet of the high-pressure boiler drum is connected to the high-pressure evaporator 13 via a downcomer. The high-pressure evaporator is connected to the high-pressure boiler drum via a riser. The steam outlet of the high-pressure boiler drum is connected to the high-pressure superheater 12. The high-pressure superheater 1 is connected to the high-pressure superheater 2 11. The high-pressure superheater 2 is connected to the high-pressure steam inlet C.

[0022] When the dual-pressure gas turbine waste heat boiler with shared economizer is in use, the high-temperature flue gas discharged from the gas turbine enters the boiler flue duct 1 from the flue gas inlet A, and then passes through the high-pressure superheater 2, high-pressure superheater 1, high-pressure evaporator, low-pressure superheater, high-temperature section of high-pressure economizer, low-pressure evaporator and the heating surface of high & low pressure shared economizer before being discharged from the chimney.

[0023] Deoxygenated boiler feedwater enters feedwater pump E from feedwater inlet B. The feedwater is then pumped to the high and low pressure shared economizer for initial heating. After heating in the economizer, the feedwater is split into two streams via the outlet header. One stream is reduced and regulated by a large differential pressure regulating valve before entering the low-pressure boiler drum. Water in the low-pressure boiler drum enters the low-pressure evaporator through a downcomer, where it is heated to produce a steam-water mixture. This mixture then enters the low-pressure boiler drum through a riser, where steam-water separation occurs. The separated saturated steam enters the low-pressure superheater, where it is heated to form superheated steam, which then enters the low-pressure steam inlet D for external use.

[0024] Another stream of hot water, initially heated by the high and low pressure shared economizer, enters the high-temperature section of the high-pressure economizer for further heating. After being heated to near saturation temperature in the high-temperature section of the high-pressure economizer, it exits from the outlet header, is regulated by a regulating valve, and enters the high-pressure boiler drum. The water in the high-pressure boiler drum enters the high-pressure evaporator through a downcomer, where it is heated to produce a steam-water mixture. The steam-water mixture enters the high-pressure boiler drum through a riser, where steam and water are separated. The separated saturated steam enters the inlet header of the first high-pressure superheater, where it is heated to form superheated steam. This superheated steam then enters the inlet header of the second high-pressure superheater through the connecting pipe between the first and second high-pressure superheaters. After further heating in the second high-pressure superheater, it enters the low-pressure steam interface C for external use.

[0025] 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 dual pressure gas turbine waste heat boiler sharing a coal economizer, comprising a boiler flue, characterized in that, The high-pressure superheater two, the high-pressure superheater one, the high-pressure evaporator, the low-pressure superheater, the high-pressure economizer high-temperature section, the low-pressure evaporator and the high & low pressure shared economizer are sequentially arranged in the boiler flue. The high & low pressure shared economizer is connected with the boiler feed water inlet, and the high & low pressure shared economizer is connected with the low-pressure drum through a pipeline. The high-pressure superheater two, the high-pressure superheater one, the high-pressure evaporator, the low-pressure superheater, the high-pressure economizer high-temperature section, the low-pressure evaporator and the high & low pressure shared economizer are sequentially arranged in the boiler flue.

2. A dual pressure gas turbine waste heat boiler incorporating an economizer as claimed in claim 1, characterized in that, A large differential pressure regulating valve is installed on the connecting pipeline between the high & low pressure shared economizer and the low-pressure drum.

3. A dual pressure gas turbine waste heat boiler incorporating an economizer as claimed in claim 1, characterized in that, A regulating valve is installed on the connecting pipeline between the high-pressure economizer high-temperature section and the high-pressure drum.

4. A dual pressure gas turbine waste heat boiler incorporating an economizer as claimed in claim 1, characterized in that, A feed water pump is installed on the connecting pipeline between the boiler feed water inlet and the high & low pressure shared economizer.

5. A dual pressure gas turbine waste heat boiler incorporating an economizer as claimed in claim 1, characterized in that, A chimney is connected to the tail end of the boiler flue.

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