Modularized detachable flue gas heat exchanger applied to low-pressure boiler

Abstract

The invention particularly relates to a modularized detachable flue gas heat exchanger applied to a low-pressure boiler, and aims to solve the problems that an existing fixed heat exchanger is difficult to clean and maintain and shut down due to faults. The low-pressure boiler comprises a deoxidizing pump, a water feeding pump, a forced circulation pump, a deaerator, a periodic blowdown flash tank, a sampling device, a dosing device, a steam pocket and a modularized detachable flue gas heat exchanger. In order to ensure the continuity of heat energy recovery, a set of forced circulation system waste heat boiler is additionally arranged in a bypass flue of the low-pressure boiler and serves as a standby of a main flue waste heat boiler. The forced circulation system waste heat boiler, namely the modularized detachable flue gas heat exchanger, mainly comprises a flue gas inlet pipe, an ascending distribution pipe, a descending distribution pipe, a plurality of detachably connected module distribution boxes and a flue gas outlet pipe. Compared with a fixed heat exchanger, the invention has the following effects: (1) the heat exchange efficiency is obviously improved, and the heat loss is effectively reduced; the heat exchange unit can be conveniently and independently cleaned, and downtime is shortened; only the fault module needs to be replaced or maintained during fault, maintenance cost is reduced, and the service life of equipment is prolonged. And (5) a user can flexibly adjust the temperature according to process requirements and freely select heat exchange module configuration to ensure that the flue gas temperature reaches the standard and meets various production requirements.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchangers, and in particular to a modular detachable flue gas heat exchanger applied to a low-pressure boiler. Background Art

[0002] A low-pressure boiler is a heat exchange device that converts the chemical energy released by fuel combustion into thermal energy and outputs hot water or steam. It is widely used in many fields such as industry, construction, and energy due to its low working pressure, simple structure, and high safety.

[0003] At present, based on their uses, low-pressure boilers can be roughly divided into steam pipes, water pipes and smoke pipes, among which the smoke pipes are used to discharge the flue gas generated by the boiler. In this process, they need to withstand the dual test of high temperature and corrosion. Therefore, after a period of operation, the flue gas heat exchange pipes of the low-pressure boiler often leak. The existing flue gas heat exchangers are usually fixed structures, which are difficult to effectively clean and maintain. If a failure occurs, the entire equipment needs to be shut down for maintenance, resulting in a decrease in production efficiency. With the shortage of energy and the improvement of environmental protection requirements, the boiler industry is in urgent need of developing efficient and energy-saving flue gas heat exchange devices. Therefore, it is particularly important to develop a detachable flue gas heat exchanger that is easy to clean and maintain.

[0004] The present invention adopts a modular detachable flue gas heat exchanger. After the fixed heat exchanger is changed to a detachable one, the plates of the heat exchanger are arranged in groups, which is convenient for installation, maintenance and replacement when a fault occurs. The user can flexibly adjust the temperature according to the process requirements and freely select the configuration of the heat exchange module to ensure that the flue gas temperature meets the standard, thereby meeting various production needs. Summary of the invention

[0005] The present invention aims to solve the problems of difficult cleaning and maintenance and failure shutdown of existing fixed heat exchangers, and proposes a modular detachable flue gas heat exchanger for low-pressure boilers.

[0006] A modular detachable flue gas heat exchanger for low-pressure boilers, characterized in that the low-pressure boiler includes a deaerator pump, a feed water pump, a forced circulation pump, a deaerator, a periodic blowdown expansion tank, a sampling device, a dosing device, a drum and a modular detachable flue gas heat exchanger. The low-pressure boiler includes a flue gas system, a steam-water system, a blowdown system, and a venting, venting, and quiescent system. The 0.4-0.6Mpa demineralized water from the demineralized water tank of the power station outside the boundary area is sent to the water storage tank through the water supply pipeline, and then sent to the deaerator through the deaerator water pump. The deoxygenated water is sent to the drum through the drum feed water pump, mixed with the high-temperature water circulating between the drum and the flue heat exchanger, and steam and water are separated. The separated saturated water continues to circulate into the flue heat exchanger for heat exchange again, and the separated saturated steam is output from the drum through pressure control and incorporated into the steam pipe network for use. To ensure the continuity of heat recovery, we added a set of forced circulation system waste heat boiler on the bypass flue of the low-pressure boiler as a backup for the waste heat boiler in the main flue. The forced circulation system waste heat boiler is a modular detachable flue gas heat exchanger, which is mainly composed of a flue gas inlet pipe, ascending and descending distribution pipes, multiple detachably connected module distribution boxes and a flue gas outlet pipe, which is easy to maintain and upgrade.

[0007] The flue gas system is a newly added forced circulation waste heat recovery system arranged in parallel with the existing waste heat boiler system, so that when the existing waste heat boiler is overhauled or fails, the newly added forced circulation waste heat recovery system meets the cooling requirements and does not affect the normal operation of the subsequent desulfurization and dust removal system. The steam-water system is a 104℃ deoxygenated water from the dry quenching area or the existing waste heat boiler deaerator entering the steam drum, and the steam drum is operated at a constant pressure of 0.8MPa. The water in the steam drum is transported to each heat exchanger module for heat exchange by a forced circulation pump through a downcomer. The water after heat exchange is separated into steam and water in the steam drum to produce 0.8MPa saturated steam and merged into the low-pressure steam network.

[0008] Furthermore, the low-pressure boiler is specifically configured as follows: Figure 1 As shown, the design pressure of the boiler drum is 1.0Mpa, the working pressure is 0.8Mpa, the working temperature is about 175℃, and the evaporation capacity is about 12.0t / h.

[0009] Further, the sampling device is connected from the boiler feed water main, the boiler outlet steam pipe and the boiler blowdown pipe.

[0010] Furthermore, the dosing device comes from the ammonia pipeline and goes to the water supply pipeline.

[0011] In order to solve the problems of difficult cleaning and maintenance and failure shutdown of existing fixed heat exchangers, this is achieved by changing the structure and design of the heat exchanger, namely, modular structure and detachable design.

[0012] Furthermore, the heat exchanger is specifically configured as follows: Figure 2As shown, the hot side medium of the flue gas heat exchanger is flue gas, and the cold side medium is saturated steam and water. The flow rate of the flue gas inlet and outlet is 250000Nm3 / h, the inlet setting temperature is 290℃, and the outlet setting temperature is 200℃.

[0013] Furthermore, the flue gas heat exchanger is a fin heat exchanger, the flue gas duct inlet is located at the left side of the bottom of the heat exchanger, and the flue gas duct outlet is located at the right side of the bottom of the heat exchanger.

[0014] The present invention significantly improves the maintainability, operability and safety of the low-pressure boiler flue gas heat exchanger by adopting a modular design. Specifically, it has the following advantages:

[0015] ①The modular and detachable design significantly improves the heat exchange efficiency and effectively reduces heat energy loss.

[0016] ② The modular structure facilitates the cleaning of heat exchange units individually, reducing maintenance costs and downtime. In case of failure, only the faulty module needs to be replaced or repaired, ensuring continuous production and extending the life of the equipment. The grouping makes installation, maintenance and replacement easier.

[0017] ③ Users can flexibly adjust the temperature according to process requirements and freely choose the heat exchange module configuration to ensure that the flue gas temperature meets the standards, thereby meeting various production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention but do not constitute a limitation of the present invention.

[0019] Figure 1 The present invention is specifically a schematic diagram of a low-pressure boiler with a modular detachable flue gas heat exchanger applied to a low-pressure boiler;

[0020] Among them: 1-circulation pump; 2-periodic sewage expansion container; 3-sampling device; 4-dosing device; 5-boiler drum; 6-modular detachable flue gas heat exchanger.

[0021] Figure 2 The present invention is specifically a partial schematic diagram of a modular detachable flue gas heat exchanger applied to a low-pressure boiler;

[0022] Among them: 1-rising distribution pipe; 2-descending distribution pipe; 3-rising branch pipe; 4-descending branch pipe; 5-steel pipe ①; 6-elbow; 7-steel pipe ②; 8-vent pipe; 9-throttling orifice plate ①; 10-throttling orifice plate ②; 11-module heat exchange box.

[0023] Figure 3 Schematic diagram of the heat exchanger. 11-water supply main pipe; 12-reducing tee; 13-return main pipe; 14-pipe cap. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited thereto.

[0025] like Figure 1 As shown, the present invention is specifically a schematic diagram of a low-pressure boiler with a modular detachable flue gas heat exchanger applied to a low-pressure boiler, including a circulating pump 1; a periodic sewage expansion container 2; a sampling device 3; a dosing device 4; a boiler drum 5; and a modular detachable flue gas heat exchanger 6.

[0026] The low-pressure boiler includes a flue gas system, a steam-water system, a sewage system, and a venting, venting, and stabilization system. The 0.4-0.6Mpa desalted water from the desalted water tank of the power station outside the boundary area is sent to the water storage tank through the water supply pipeline, and then sent to the deaerator through the deoxygenated water pump. The deoxygenated water is sent to the drum through the drum feed water pump, and mixed with the high-temperature water circulating between the drum and the flue heat exchanger to separate steam and water. The separated saturated water continues to circulate into the flue heat exchanger for heat exchange again, and the separated saturated steam is output from the drum through pressure control and incorporated into the steam network for use. In order to ensure the continuity of heat recovery, we added a set of forced circulation system waste heat boilers on the bypass flue of the low-pressure boiler as a backup for the main flue waste heat boiler.

[0027] The flue gas system is a newly added forced circulation waste heat recovery system arranged in parallel with the existing waste heat boiler system, so that when the existing waste heat boiler is overhauled or fails, the newly added forced circulation waste heat recovery system meets the cooling requirements and does not affect the normal operation of the subsequent desulfurization and dust removal system. The steam-water system is a 104℃ deoxygenated water from the dry quenching area or the existing waste heat boiler deaerator entering the steam drum, and the steam drum is operated at a constant pressure of 0.8MPa. The water in the steam drum is transported to each heat exchanger module for heat exchange by a forced circulation pump through a downcomer. The water after heat exchange is separated into steam and water in the steam drum to produce 0.8MPa saturated steam and merged into the low-pressure steam network.

[0028] like Figure 2 As shown, the present invention is specifically a partial schematic diagram of a modular detachable flue gas heat exchanger applied to a low-pressure boiler, including an ascending distribution pipe 1; a descending distribution pipe 2; an ascending branch pipe 3; a descending branch pipe 4; a steel pipe ①5; an elbow 6; a steel pipe ②7; a vent pipe 8; a throttling orifice plate ①9; a throttling orifice plate ②10; and a modular heat exchange box 11. Figure 3 It is an overall schematic diagram of a modular detachable flue gas heat exchanger. A water supply main pipe 11; a reducing tee 12; a return water main pipe 13; and a pipe cap 14.

[0029] In order to solve the problems of difficult cleaning and maintenance and downtime of existing fixed heat exchangers, the structure and design of the heat exchanger are changed to achieve modular structure and detachable design. The flue gas heat exchanger has a total of 14 groups of modular heat exchange boxes, one group includes 8 groups of risers and 4 groups of downcomers, the size of the riser is Φ48×3mm, and the size of the downcomer is Φ57×3.5mm. There is a partition inside the steam box, with two risers on one side and one downcomer on the other. The throttling baffle 1 and the steel pipe of the throttling baffle meet the GB / T3087-2022 standard and are qualified. The throttling baffle is installed in front of the tee of the descending distribution pipe along the flue gas direction.

[0030] The present invention adopts a modular detachable flue gas heat exchanger. After the fixed heat exchanger is changed to a detachable one, the plates of the heat exchanger are arranged in groups, which is convenient for installation, maintenance and replacement when a fault occurs. The user can flexibly adjust the temperature according to the process requirements and freely select the configuration of the heat exchange module to ensure that the flue gas temperature meets the standard, thereby meeting various production needs.

[0031] The above partial embodiments are only for illustrating the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the present invention. The present invention is not limited to the specific technical solutions described in the above embodiments, and any technical solutions formed by equivalent replacement shall fall within the protection scope required by the present invention.

Claims

1. A modular detachable flue gas heat exchanger for a low-pressure boiler, characterized in that: The purpose of the modular detachable flue gas heat exchanger is to solve the problems of difficult cleaning and maintenance and downtime of existing fixed heat exchangers. When the existing waste heat boiler is overhauled or fails, the cooling requirements can be met without affecting the normal operation of the subsequent desulfurization and dust removal system. The low-pressure boiler includes a deaerator pump, a feed water pump, a forced circulation pump, a deaerator, a periodic blowdown expansion tank, a sampling device, a dosing device, a steam drum and a modular detachable flue gas heat exchanger. To ensure the continuity of heat recovery, we add a set of forced circulation system waste heat boilers on the bypass flue of the low-pressure boiler as a backup for the main flue waste heat boiler. The forced circulation system waste heat boiler is a modular detachable flue gas heat exchanger, which is mainly composed of a flue gas inlet pipe, an ascending and descending distribution pipe, a plurality of detachably connected module distribution boxes and a flue gas outlet pipe, which is easy to maintain and upgrade.

2. The low-pressure boiler according to claim 1, characterized in that: The specific configuration of the low-pressure boiler is shown in Figure 1. 104°C deoxygenated water from the dry quenching area or the existing waste heat boiler deaerator enters the steam drum, and the steam drum operates at a constant pressure of 0.8 MPa. The water in the steam drum is transported to each heat exchanger module for heat exchange through a downcomer by a forced circulation pump. After heat exchange, the water is separated into steam and water in the steam drum to generate 0.8 MPa saturated steam, which is then incorporated into the low-pressure steam network.

3. The low-pressure boiler according to claim 1, characterized in that: The specific setting of the low-pressure boiler is shown in Figure 1. The design pressure of the drum is 1.0Mpa, the working pressure is 0.8Mpa, the working temperature is about 175℃, and the evaporation capacity is about 12.0t / h.

4. The low-pressure boiler according to claim 1, characterized in that: The specific configuration of the low-pressure boiler is shown in Figure 1. The sampling device is connected to the boiler feed water main, the boiler outlet steam pipe and the boiler blowdown pipe.

5. The low-pressure boiler according to claim 1, characterized in that: The specific configuration of the low-pressure boiler is shown in Figure 1. The dosing device comes from the ammonia pipeline and goes to the water supply pipeline.

6. The modular detachable flue gas heat exchanger according to claim 1, characterized in that: In order to solve the problems of difficult cleaning and maintenance and failure shutdown of existing fixed heat exchangers, this is achieved by changing the structure and design of the heat exchanger, namely, modular structure and detachable design.

7. The modular detachable flue gas heat exchanger according to claim 1, characterized in that: The specific setting of the heat exchanger is shown in Figure 2, where the hot side medium of the flue gas heat exchanger is flue gas, and the cold side medium is saturated steam and water. The flow rate of the flue gas inlet and outlet is 250000Nm3 / h, the inlet temperature is set at 290℃, and the outlet temperature is set at 200℃.

8. The modular detachable flue gas heat exchanger according to claim 1, characterized in that: The flue gas heat exchanger is a fin heat exchanger.

9. The heat exchanger according to claim 1, characterized in that: The flue gas duct inlet is located at the left side of the bottom of the heat exchanger, and the flue gas duct outlet is located at the right side of the bottom of the heat exchanger.

Images