A multi-stage coupled heat exchanger

Abstract

The present application relates to a kind of multistage coupled heat exchanger, belong to oxygen removal heat exchange equipment technical field.The upper heat exchanger for processing unit low load operation when water inlet mixing heat exchange and the lower heat exchanger for processing unit high load operation when water inlet mixing heat exchange are included;Upper heat exchanger is connected with lower heat exchanger;Upper heat exchanger includes water spray tray heating device;Lower heat exchanger includes rotary film atomizer device and nozzle heating device.The multistage coupled heat exchanger provided by the present application is stable high, heat exchange performance is good, oxygen removal performance is good, adjustable ability is strong, multi-working condition adaptive capacity is strong and comprehensive benefit is high.

Description

Technical Field

[0001] This invention relates to a multi-stage coupled heat exchanger, belonging to the technical field of deoxygenation heat exchange equipment. Background Technology

[0002] Hybrid deaerator heat exchangers are one of the key components of power plant regenerative systems. They introduce steam at a certain pressure into water, using the steam to heat the water to its saturation temperature under the container pressure. This reduces the solubility of non-condensable gases in the water, thereby achieving heat exchange and deaeration, and ultimately extending the lifespan of the power generation system equipment.

[0003] Traditional split-type deaerators have an upper deaerator head connected to a lower water storage tank. For units that need to change operating conditions to include heating functionality, the deaeration and heat exchange capacity of traditional split-type deaerators is insufficient, resulting in excessively high oxygen content and low outlet water temperature, failing to meet the operational requirements of complex conditions. Integrated deaerators with a single water tank have the heat exchange heating device installed in the water storage tank, allowing steam to diffuse extensively within the tank. However, this results in significant vibration and high heat loss during low-load operation. Therefore, there is an urgent need in this technical field for a deaerator heat exchange device that can meet the diverse operating conditions of power plants, adapt well to unit operation during peak and trough periods, and improve the overall efficiency of the unit. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problem of how to obtain a deaeration heat exchange device that can meet the changing operating conditions of power plants, adapt well to the operation of the unit during peak and trough periods, and improve the overall efficiency of the unit.

[0005] To address the aforementioned problems, the present invention provides a multi-stage coupled heat exchanger, comprising an upper heat exchanger for handling influent water mixing heat exchange during low-load operation of the unit and a lower heat exchanger for handling influent water mixing heat exchange during high-load operation of the unit; the upper heat exchanger is connected to the lower heat exchanger; the upper heat exchanger includes a water-spraying disc heating device; and the lower heat exchanger includes a swirl film atomizer device and a spray pipe heating device.

[0006] Preferably, the lower heat exchanger further includes a boiler start-up drain device, a spray-type auxiliary steam device, and a drain chamber.

[0007] Preferably, a shut-off valve is provided between the upper heat exchanger and the lower heat exchanger.

[0008] Preferably, the swirl film atomizer device is a two-stage device; the swirl film atomizer device includes an upper chamber and a lower chamber that are connected to each other.

[0009] Preferably, a spring is provided between the upper chamber and the lower chamber.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The multi-stage coupled heat exchanger provided by this invention has high stability, good heat exchange performance, good deoxygenation performance, strong adjustability, strong adaptability to multiple operating conditions, and high overall benefits. Attached Figure Description

[0012] Figure 1 This is a simplified schematic diagram of a traditional split-type deaerator.

[0013] Figure 2 This is a simplified schematic diagram of the multi-stage coupled heat exchanger of the present invention.

[0014] Figure 3 This is a schematic diagram of a rotary film atomizer.

[0015] Figure 4 for Figure 3 Top view.

[0016] Figure 5 This is a schematic diagram of a rotary film atomizer installed in the form of a flange.

[0017] Figure reference numerals: 1. Rotary film atomizer device; 2. Spray nozzle heating device; 3. Boiler start-up drain device; 4. Spray nozzle auxiliary steam device; 5. Drain chamber; 6. Sprinkler plate heating device; 7. Nozzle atomizer device; 8. Upper heat exchanger; 9. Lower heat exchanger; 10. Upper chamber; 11. Spring; 12. Lower chamber Detailed Implementation

[0018] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings:

[0019] like Figure 1-5 As shown, the technical solution adopted by the present invention is to provide a multi-stage coupled heat exchanger, including an upper heat exchanger 8 for handling the mixing and heat exchange of inlet water during low-load operation of the unit and a lower heat exchanger 9 for handling the mixing and heat exchange of inlet water during high-load operation of the unit; the upper heat exchanger 8 and the lower heat exchanger 9 are connected; the upper heat exchanger 8 includes a water-spraying disc heating device 6; the lower heat exchanger 9 includes a swirl film atomizer device 1 and a spray pipe heating device 2. The lower heat exchanger 9 also includes a boiler start-up drain device 3, a spray pipe auxiliary steam device 4, and a drain chamber 5. A shut-off valve is provided between the upper heat exchanger 8 and the lower heat exchanger 9. The swirl film atomizer device 1 is a two-stage device, including a connected upper chamber 10 and a lower chamber 12. A spring 11 is provided between the upper chamber 10 and the lower chamber 12.

[0020] Example

[0021] This invention solves the technical problem that existing deaerator heat exchangers cannot well adapt to the multi-condition operation required by the unit; it can also provide other additional benefits. 1. It can meet the low noise requirement under pure condensing operation during unit startup; 2. It can meet the heat exchange requirements of unit switching to large-scale heating and deaerator operation; 3. It can be used as a receiving device for high-energy media such as boiler start-up condensate, providing energy dissipation and emission reduction functions; 4. It can be switched to an energy storage device to store energy in the system.

[0022] This invention provides a multi-stage coupled heat exchanger. The upper part of the heat exchanger is a horizontal-spray plate type heat exchange device, and the lower part is a horizontal-spray pipe type heat exchange device. The upper heat exchanger 8 includes a spray plate type heating device 6 and a nozzle atomizer device 7; the upper heat exchanger 8 consists of a spray heat exchange section and a deep heat exchange section. The spray heat exchange section uses multiple low-flow nozzles of the nozzle atomizer device 7 to perform preliminary atomization and deoxygenation, while increasing the heat exchange area between water and heating steam; after being atomized by the nozzles, the water falls onto the spray plate and further exchanges heat with the heating steam to achieve deep deoxygenation.

[0023] The lower heat exchanger 9 includes a swirl film atomizer device 1, a spray pipe heating device 2, a boiler start-up condensate device 3, a spray pipe auxiliary steam device 4, and a condensate chamber 5; the lower heat exchanger 9 consists of a spray heat exchange section, a deep heat exchange section, and a water storage tank.

[0024] The spray heat exchange section introduces condensate into the upper water chamber of the shell, where it is atomized and sprayed out under pressure differential via a swirl film atomizer 1, entering the spray deoxygenation section. In this section, water contacts heating steam for deoxygenation, and some non-condensable gases are removed and discharged into the atmosphere through the exhaust pipe. The upper water-spraying disc heat exchanger 6 is suitable for operation under low-load conditions; the lower spray nozzle heat exchanger is used under high-load conditions. This multi-stage coupled heat exchanger can meet both low-noise operation under low-load conditions and deoxygenation heat exchange requirements under high-load conditions, making it an advanced type of deoxygenation heat exchanger.

[0025] A two-stage swirl film atomizer was used in the lower heat exchanger. The atomization effect and load-bearing capacity of the swirl film atomizer are important factors that directly determine the heat exchange efficiency of the coupled heat exchanger. By using a two-stage swirl film atomizer, the water droplets are atomized into very small sizes, thus accelerating the heating process of the water droplets and the diffusion process of dissolved gases in the water into the steam space.

[0026] Working principle and characteristics of a two-stage rotary film atomizer:

[0027] 1. It adopts a two-stage design. The front stage uses an expansion and stabilization chamber to allow the fluid to be fully and stably expanded. The rear stage uses a swirl film diffuser. The swirl film diffuser automatically adjusts the opening of the swirl film atomizer according to the change in flow rate (pressure difference before and after the swirl film atomizer).

[0028] 2. It automatically adjusts according to the flow rate and pressure difference, and adopts a specially designed high-performance spring 11 combined with the swirl film crushing and atomizing chamber. It has good automatic centering and high stability, which is suitable for reciprocating operation and can meet the needs of flow regulation.

[0029] 3. The swirl film atomizer utilizes a special swirl film design. Condensate is tangentially ejected from specially designed orifices, forming a high-speed rotating water film flowing downwards. This film forms a conical water film skirt at the outlet of the swirl diffuser's vortex tube, achieving impact and atomization. Heating steam enters the swirl jet zone on the inner and outer surfaces of the water film skirt, exchanging energy with the condensate. Ultimately, this results in highly efficient swirl film atomization and atomization of the water droplets. Due to the entrainment effect of the jet, the high-speed rotating water film exchanges heat and mass with the heating steam. As the condensate is continuously heated by the steam and the pressure of the water ejected from the jet orifice decreases, dissolved oxygen, air, and other non-condensable gases gradually precipitate out, achieving highly efficient deoxygenation and significantly improving the deoxygenation effect.

[0030] 4. It has a large heat transfer coefficient and good deoxygenation heat exchange effect. When used in conjunction with other equipment, it can meet the requirement that the oxygen content of the deaerator effluent is ≤5ppb.

[0031] 5. The inlet and outlet water temperatures rise significantly, meeting the requirements for heat exchange with large temperature differences.

[0032] 6. Special spring adjustment allows for rapid load changes and can operate under constant sliding pressure.

[0033] 7. It has strong adaptability and can meet the requirements of stable operation of the unit under 10% to 110% of the rated load. The oxygen content of the effluent meets the national standard, and the time required to reach qualified dissolved oxygen is short.

[0034] 8. Due to the high efficiency of the swirl film crusher and atomization, the heat exchange effect is sufficient, the steam consumption is low, the exhaust steam loss is small, which effectively improves the economic benefits of the unit and reduces exhaust loss, thus improving the thermal efficiency of the unit.

[0035] 9. The rotary film atomizer is suitable for poor water quality without clogging. It can filter larger particles of debris. At the bottom of the rotary film atomizer, debris that can pass through the filter can also pass through the gaps in the rotary film atomizer. The rotary film atomizer has a built-in dirt collector that blocks coarse particles in the main condensate (which will not remain in the equipment after proper rinsing). It requires no maintenance after installation.

[0036] 10. The rotary film atomizer is designed with a rated flow rate of 600T / H.

[0037] 11. The differential pressure range of the rotary film atomizer is 0.2-0.98 bar.

[0038] 12. The swirl film atomizer and diffuser are all made of high-quality stainless steel, which is resistant to erosion and suitable for long-term spraying.

[0039] 13. The service life of the rotary film atomizer can meet the requirements of 30-year unit use.

[0040] 14. The main body weighs approximately 80 kg.

[0041] The swirl film atomizer can be easily installed inside a deaerator by connecting to external pipelines via flanges. Constructed from sheet metal, the device is easy to manufacture and requires minimal maintenance. Using this device, large quantities of water can be rapidly and evenly atomized and distributed throughout the deaerator, while effectively controlling vibration during operation. The device significantly improves the start-up speed of the heat exchanger, reduces operating noise and temperature gradients caused by uneven heating, increases energy efficiency, and lowers equipment procurement and plant investment costs, thereby enhancing the economic viability of power plant construction.

[0042] The multi-stage coupled heat exchanger of this invention has high stability, good heat exchange performance, good deoxygenation performance, strong adjustability, strong adaptability to multiple operating conditions, and high overall benefits.

[0043] like Figure 1 The image shows a traditional split-type deaerator, with a heat exchange and deaeration device at the top and a water storage tank at the bottom.

[0044] like Figure 2 The diagram shows a multi-stage coupled heat exchanger, with a water-spraying disc heat exchanger at the top and a spray nozzle heat exchanger at the bottom. The lower heat exchanger 9 includes a swirl film atomizer device 1, a spray nozzle heating device 2, a boiler start-up condensate drain device 3, a spray nozzle auxiliary steam device 4, and a condensate chamber 5. The swirl film atomizer device 1 is mounted on the deaerator body via a flange to perform preliminary deaeration of the incoming water. The heating steam in the spray nozzle heating device 2 deeply heats and deaerates the water in the tank through perforated heat exchange tubes. The boiler start-up condensate drain device 3 dissipates energy from the boiler start-up condensate, which is then used for heating and deaeration, reducing energy consumption. The spray nozzle auxiliary steam device 4 heats the water in the tank through perforated heat exchange tubes. The condensate chamber 5 is used to drain the water from the heat exchanger, preventing the heating steam from mixing with the condensate.

[0045] During startup, the lower heat exchanger 9 first raises the water level in the shell to the startup level through the water inlet spray device, then closes the water inlet. Next, the auxiliary steam device slowly heats the water to approximately 130°C. Water continues to be injected into the shell through the water inlet device until the normal water level is reached, then the main heating device is activated and maintained to ensure normal operating conditions within the shell. During low-load operation, the upper heat exchanger is activated for deoxygenation, and the air and water inlet pipes of the lower heat exchanger are closed through shut-off valves, disabling the heating and deoxygenation function; it is used only as a water storage tank. During high-load operation, the lower heat exchanger 9 is activated for deoxygenation, and the upper heat exchanger 8 is shut down. The connecting pipes between the upper and lower parts are closed through shut-off valves, isolating the upper heat exchanger 8.

[0046] like Figure 3 The diagram shows the structure of a swirl film atomizer, including an upper chamber 10, a spring 11, and a lower chamber 12. When the swirl film atomizer is in operation, the incoming water expands within the upper chamber 10 and is ejected through small holes in the lower chamber 12, atomizing the water. The water is then heated by steam to precipitate non-condensable gases. The two chambers are connected by the spring 11 for a buffer transition. During transport, the spring 11 is extended, allowing the lower chamber 12 to retract into the upper chamber 10; during operation, the spring 11 is compressed, allowing the lower chamber 12 to extend beyond the upper chamber 10.

[0047] This invention provides a multi-stage coupled heat exchanger that combines a water-spraying disc heat exchanger and a spray nozzle heat exchanger, and utilizes a fluid swirl film atomizer device. It is adaptable to both low-load and high-load operation of the unit, reducing energy consumption of the deaerator. It can be used in power plants with capacity expansion and renovation needs, reducing costs and improving overall profitability for power plant upgrades.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A multi-stage coupled heat exchanger, characterized in that, It includes an upper heat exchanger for handling the mixing and heat exchange of the influent water when the unit is operating at low load and a lower heat exchanger for handling the mixing and heat exchange of the influent water when the unit is operating at high load; the upper heat exchanger is connected to the lower heat exchanger; when the unit is operating at low load, the upper heat exchanger is activated for deoxygenation, and the lower heat exchanger is deactivated for heating and deoxygenation and is only used as a water storage tank; when the unit is operating at high load, the lower heat exchanger is activated for deoxygenation, the upper heat exchanger is stopped and isolated; The upper heat exchanger includes a water-spraying disc heating device; the lower heat exchanger includes a swirl film atomizer device and a spray pipe heating device; the swirl film atomizer device includes an upper chamber and a lower chamber connected thereto, with a spring between them, the spring allowing the lower chamber to extend and retract into the upper chamber.

2. The multi-stage coupled heat exchanger according to claim 1, characterized in that, The lower heat exchanger also includes a boiler start-up drain device, a spray-type auxiliary steam device, and a drain chamber.

3. A multi-stage coupled heat exchanger according to claim 1, characterized in that, A shut-off valve is provided between the upper heat exchanger and the lower heat exchanger.

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