Recovery system utilizing boiler blow-off waste heat
By introducing a heat exchange system into the boiler sewage discharge system, and using regular and continuous sewage discharged to exchange heat through multiple heat exchangers, the problem of incomplete utilization of waste heat of the boiler sewage discharged is solved, efficient recycling and utilization of waste heat is achieved, and the temperature of discharged water and waste of water resources is reduced.
Patent Information
- Application Number
- CN202420555068.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-20
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2034-03-20
AI Technical Summary
In the prior art, the waste heat of the boiler sewage discharged is incomplete, resulting in high sewage temperature, waste of water resources, and affecting energy conservation and consumption reduction and plant environment.
A recycling system using waste heat of waste heat of the boiler is designed, including at least one boiler, water softener, water supply tank and sewage cooling tank, and is equipped with a sewage expansion container and a heat exchange system. By regularly and continuously discharged sewage, heat exchange and cooling is carried out through the first and second heat exchangers, the waste heat is recovered and utilized at a stage.
It effectively absorbs the waste heat from the boiler sewage discharged, reduces the temperature of the sewage discharged, improves energy utilization, reduces water resource waste, and improves the environment of the factory.
Smart Images
Figure CN222669962U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the field of waste heat recovery, and in particular relates to a recovery system utilizing waste heat from boiler sewage discharge. Background Art
[0002] In order to ensure that the boiler water quality meets the specifications and operation requirements, the boiler needs to be regularly discharged when it is started, and the boiler needs to be continuously discharged during operation. The temperature of regular and continuous sewage discharge is relatively high and contains a large amount of waste heat from sewage discharge.
[0003] At present, for small boiler rooms, the sewage is directly discharged into the sewage cooling pool, and tap water is passed into the sewage cooling pool to cool the sewage. Although the waste heat of the sewage of the small boiler room boiler is not large, in order to cool the sewage, the sewage in the sewage cooling pool needs to be cooled to 40℃ before it can be discharged. Therefore, tap water needs to be passed into the sewage cooling pool to cool the sewage to meet the standard, resulting in a waste of water resources and the release of a large amount of white steam, which affects the appearance of the factory area and causes white pollution.
[0004] For large boiler rooms, the boiler sewage has a large amount of waste heat, and the sewage is discharged into the expansion tank, where the sewage is expanded to produce low-pressure flash steam. The water outlet of the expansion tank is connected to the sewage cooling pool, but the sewage after expansion is still at a high temperature and still requires a large amount of tap water for cooling. This part of the waste heat is not fully utilized, and water is lost by evaporation. The heat of the sewage is also lost in vain, which is not conducive to energy conservation and consumption reduction. It also causes a waste of water resources and does not save water resources. Summary of the invention
[0005] The utility model aims to provide a system for utilizing waste heat from industrial boiler sewage in view of the deficiencies in the prior art, so as to solve the problems of incomplete utilization of waste heat from sewage, high temperature of sewage and waste of water resources.
[0006] The technical solution adopted by the purpose of the utility model is:
[0007] A recovery system utilizing waste heat from boiler sewage, comprising at least one boiler, a water softener, a feed water tank and a sewage cooling pool, wherein the boiler is provided with a sewage expansion tank and a heat exchange system, wherein the heat exchange system comprises at least a first heat exchanger and a second heat exchanger, wherein a regular sewage outlet of the boiler is connected to a sewage inlet of the first heat exchanger via a first regular sewage pipe, a continuous sewage outlet of the boiler is connected to the sewage expansion tank via a first continuous sewage pipe, a water outlet of the sewage expansion tank is connected to a sewage inlet of the second heat exchanger via a second continuous sewage pipe, a sewage outlet of the first heat exchanger is connected to the sewage cooling pool via a second regular sewage pipe, a sewage outlet of the second heat exchanger is connected to the sewage cooling pool via a third continuous sewage pipe, a water inlet of the first heat exchanger and a water inlet of the second heat exchanger are respectively connected to the water softener via a softened water pipe, the water softener is connected to a tap water pipe, and a water outlet of the first heat exchanger and a water outlet of the second heat exchanger are respectively connected to the feed water tank via a softened return water pipe.
[0008] Further, the softened water pipeline includes a first softened water pipeline and a second softened water pipeline, the softened return water pipeline includes a first softened return water pipeline and a second softened return water pipeline, the water softener is respectively connected to the first softened water pipeline and the second softened water pipeline through a tee, the water inlet of the first heat exchanger is connected to the first softened water pipeline, the water inlet of the second heat exchanger is connected to the second softened water pipeline, the water outlet of the first heat exchanger is connected to the second softened water pipeline, the water outlet of the second heat exchanger is connected to the water supply tank through the first softened return water pipeline, the second softened return water pipeline is connected between the second softened water pipeline and the first softened return water pipeline, the water inlet of the first heat exchanger is provided with a first on-off valve, and the water outlet is provided with a second on-off valve, the water inlet of the second heat exchanger is provided with a third on-off valve, and the water outlet is provided with a fourth on-off valve, the second softened water pipeline is provided with a fifth on-off valve, and the second softened return water pipeline is provided with a sixth on-off valve.
[0009] Furthermore, the first on-off valve, the second on-off valve, the third on-off valve, the fourth on-off valve, the fifth on-off valve and the sixth on-off valve are all ball valves.
[0010] Furthermore, the first periodic sewage discharge pipe, the second periodic sewage discharge pipe, the first continuous sewage discharge pipe, the second continuous sewage discharge pipe and the third continuous sewage discharge pipe are all provided with a seventh on-off valve, and the seventh on-off valve is a stop valve.
[0011] Furthermore, it also includes a sewage control system, which includes a sewage controller, a sewage control valve and a sensor. The sewage control valve and the sensor are arranged on the first continuous sewage pipe. The sewage controller is electrically connected to the sensor and the sewage control valve respectively. The sensor is used to detect the conductivity of the sewage and send it to the sewage controller. The sewage controller controls the operation of the sewage control valve.
[0012] Furthermore, the flash steam pipe at the top of the sewage expansion tank is connected to the water supply tank, and the flash steam pipe extends at least 300 mm below the lowest water level line in the sewage expansion tank. The lower section of the flash steam pipe below the water level line is provided with multiple rows of through holes.
[0013] Furthermore, the spacing between each row of the multiple rows of through holes is no more than 25 mm.
[0014] Furthermore, the flash steam pipeline at the top of the blowdown expansion tank is connected to the deaerator.
[0015] The above technical solution has the following beneficial effects:
[0016] The utility model has a simple structure and is equipped with at least two heat exchangers. The boiler's periodic sewage is directly cooled by heat exchange through the first heat exchanger and then enters the sewage cooling pool. The boiler's continuous sewage is expanded by using a sewage expansion tank and then heat exchanged through the second heat exchanger. It not only absorbs the waste heat of sewage, but also reduces the temperature of the sewage cooling pool, thus realizing the cascade and efficient recycling of waste heat. It absorbs the waste heat of continuous and periodic sewage discharge from the boiler, improves energy utilization, and reduces the temperature of sewage discharge.
[0017] The water inlets of the two heat exchangers are connected to the water softener connected to the tap water. The system can be operated by using the pressure of the tap water without the need for additional power-consuming equipment such as pumps, thus reducing the equipment investment cost. At the same time, the tap water consumption of the sewage cooling pool is also reduced, thus saving water. The softened water after absorbing heat is sent to the water tank for use by the boiler.
[0018] The addition of a sewage control system can avoid excessive and continuous sewage discharge from industrial boilers during operation, thereby avoiding the loss of heat and water.
[0019] The water inlet of the first heat exchanger is provided with a first on-off valve, and the water outlet is provided with a second on-off valve; the water inlet of the second heat exchanger is provided with a third on-off valve, and the water outlet is provided with a fourth on-off valve; the second softened water pipeline is provided with a fifth on-off valve, and the second softened return water pipeline is provided with a sixth on-off valve. By controlling each on-off valve, the first heat exchanger for periodic sewage discharge and the second heat exchanger for continuous sewage discharge can be cut off as needed, and each heat exchanger can be inspected and maintained.
[0020] The flash steam pipe extends at least 300 mm below the lowest water level line in the sewage expansion tank, and a plurality of rows of through holes are provided in the lower section of the flash steam pipe below the water level line, thereby improving the effect of recovering flash steam.
[0021] Further description is given below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a structural schematic diagram of specific embodiment 1.
[0023] In the accompanying drawings, 1 is a boiler, 2 is a sewage expansion tank, 3 is a heat exchange system, 4 is a water softener, 5 is a water supply tank, 6 is a sewage cooling pool, 7 is a first regular sewage pipe, 8 is a first continuous sewage pipe, 9 is a second continuous sewage pipe, 10 is a third continuous sewage pipe, 11 is a softened water pipe, 12 is a softened return water pipe, 13 is a flash steam pipe, 14 is a first on-off valve, 15 is a second on-off valve, 16 is a third on-off valve, 17 is a fourth on-off valve, 18 is a fifth on-off valve, 19 is a sixth on-off valve, 20 is a seventh on-off valve, 21 is a sewage controller, 22 is a sewage control valve, and 23 is a sensor. DETAILED DESCRIPTION Specific embodiment 1:
[0025] See also Figure 1 As shown, a recovery system utilizing waste heat from boiler sewage includes at least one boiler 1, a sewage expansion tank 2, a water softener 4, a feed water tank 5, a sewage cooling tank 6 and a heat exchange system 3, wherein the heat exchange system 3 includes at least a first heat exchanger and a second heat exchanger. In this specific embodiment, two boilers 1 are provided, and the two boilers 1 are equipped with a sewage expansion tank, and the heat exchange system includes a first heat exchanger and a second heat exchanger. Two regular sewage outlets are provided at the bottom of the boiler 1, and a continuous sewage outlet is provided at the upper part of the boiler. The regular sewage outlet of the boiler is connected to the sewage inlet of the first heat exchanger through a first regular sewage pipe 7, and the continuous sewage outlet of the boiler is connected to the sewage expansion tank 2 through a first continuous sewage pipe 8. The water outlet of the sewage expansion tank is connected to the sewage inlet of the second heat exchanger through a second continuous sewage pipe 9. The water outlet of the sewage expansion tank 2 is provided with four stop valves for closing and opening the second continuous sewage pipe 9. ，The sewage outlet of the first heat exchanger is connected to the sewage cooling pool 6 through the second regular sewage pipe, and the sewage outlet of the second heat exchanger is connected to the sewage cooling pool 6 through the third continuous sewage pipe 10. The first regular sewage pipe 7, the second regular sewage pipe, the first continuous sewage pipe 8, the second continuous sewage pipe 9 and the third continuous sewage pipe 10 are all provided with a seventh on-off valve 20, and the seventh on-off valve 20 is a stop valve. The water inlet of the first heat exchanger and the water inlet of the second heat exchanger are respectively connected to the water softener 4 through the softened water pipe 11, and the water softener 4 is connected to the tap water pipe. The water outlet of the first heat exchanger and the water outlet of the second heat exchanger are respectively connected to the water supply tank 5 through the softened return water pipe 12. In this specific embodiment: the softened water pipeline 11 includes a first softened water pipeline and a second softened water pipeline, the softened return water pipeline 12 includes a first softened return water pipeline and a second softened return water pipeline, the water softener is connected to the first softened water pipeline and the second softened water pipeline respectively through a tee, the water inlet of the first heat exchanger is connected to the first softened water pipeline, the water inlet of the second heat exchanger is connected to the second softened water pipeline, the water outlet of the first heat exchanger is connected to the second softened water pipeline, the water outlet of the second heat exchanger is connected to the water supply tank 5 through the first softened return water pipeline, the second softened return water pipeline is connected between the second softened water pipeline and the first softened return water pipeline, the water inlet of the first heat exchanger is provided with a first on-off valve 14, the water outlet is provided with a second on-off valve 15, the water inlet of the second heat exchanger is provided with a third on-off valve 16, the water outlet is provided with a fourth on-off valve 17, the second softened water pipeline is provided with a fifth on-off valve 18, and the second softened return water pipeline is provided with a sixth on-off valve 19. The first on-off valve 14, the second on-off valve 15, the third on-off valve 16, the fourth on-off valve 17, the fifth on-off valve 18 and the sixth on-off valve 19 are all ball valves. This structural layout combines pipelines, saves costs, and realizes flexible switching of the first heat exchanger and the second heat exchanger by controlling the on-off of each ball valve, which facilitates replacement and maintenance of the heat exchanger.
[0026] The flash steam pipe 13 at the top of the blowdown expansion tank is connected to the water supply tank 5, and the flash steam pipe 13 extends at least 300mm below the lowest water level line in the blowdown expansion tank. The flash steam pipe 13 is provided with multiple rows of through holes in the lower section below the water level line, and the row spacing of each row of the multiple rows of through holes is no more than 25mm. In this specific embodiment: 10 rows of small holes with a diameter of 10mm are drilled in the lower section below the water level line of the flash steam pipe 13, 4 holes in each row, and the row spacing is 20mm, so as to achieve a better effect of recovering flash steam, and the flash steam of the blowdown expansion tank is connected to the water supply tank 5 for recycling.
[0027] Possibly, it also includes a sewage control system, which includes a sewage controller 21, a sewage control valve 22 and a sensor 23. The sewage control valve 22 and the sensor 23 are arranged on the first continuous sewage pipe 8. The sewage controller 21 is electrically connected to the sensor 23 and the sewage control valve 22 respectively. The sensor is used to detect the conductivity of the sewage, and the dissolved solids in the boiler water can be inferred by the conductivity and sent to the sewage controller. The sewage controller controls the action of the sewage control valve, and the sewage control valve is an electric regulating valve. When the dissolved solids exceed the boiler water quality requirements, the sewage controller automatically opens the sewage control valve, which effectively avoids excessive discharge of continuous sewage from the industrial boiler during operation and avoids the loss of heat and water. In this specific embodiment, each boiler is correspondingly provided with a sensor and a sewage control valve, and the sensors and sewage control valves of the two boilers are electrically connected to the sewage controller 21. Specific embodiment 2:
[0029] The characteristic of this specific embodiment is that it also includes a deaerator, and the flash steam pipe 13 at the top of the blowdown expansion tank is connected to the deaerator. Other characteristics are the same as those of the specific embodiment 1, so they are omitted in this specific embodiment.
[0030] The working principle of this utility model:
[0031] When the boiler is started, regular sewage discharge will be carried out, and the regular sewage will be sent to the first heat exchanger for heat exchange. The cold side of the first heat exchanger is tap water softened by the water softener.
[0032] When the boiler is running, continuous sewage discharge is carried out, and the continuous sewage is sent to the continuous sewage expansion tank for expansion. The low-pressure flash steam generated after the expansion is sent to the water tank 5 for use or to the deaerator, and the expanded continuous sewage is still at a high temperature. The expanded continuous sewage is sent to the second heat exchanger for heat exchange. The cold side of the second heat exchanger is tap water softened by the water softener. The softened water after absorbing heat is then sent to the water tank 5 to provide softened water for the boiler, thereby improving energy utilization and reducing gas consumption.
[0033] After the regular sewage and the continuous sewage after the expansion release heat, the temperature is reduced and then sent to the outdoor sewage cooling pool 6 for cooling. The cooled sewage is discharged to the outdoor cooling pool, and the sewage can be cooled to below 40°C for discharge using less tap water.
[0034] The fresh softened water part of the heat exchange system is equipped with 6 ball valves, which can freely cut off the first heat exchanger and the second heat exchanger for maintenance. For example, open the fifth on-off valve 18, the third on-off valve 16, and the fourth on-off valve 17, and close the first on-off valve 14, the second on-off valve 15, and the sixth on-off valve, then the first heat exchanger that discharges sewage regularly is cut off, and the heat exchanger can be repaired. Similarly, open the first on-off valve 14, the second on-off valve 15, and the sixth on-off valve, and close the fifth on-off valve 18, the third on-off valve 16, and the fourth on-off valve 17, then the second heat exchanger that discharges sewage continuously is cut off, and the heat exchanger can be repaired.
[0035] This system is safe, reliable and low-cost. It only needs to set up a continuous blowdown expansion tank and two heat exchangers. No power-consuming equipment is added. It can use the pressure of tap water. Since the boiler needs fresh water replenishment at all times during operation, the system has a reliable and stable heat absorption source. As long as the boiler is started and operated, fresh softened water is needed to stably absorb the waste heat of boiler blowdown. At the same time, there is a linear relationship between the boiler's blowdown volume and the boiler's fresh water replenishment volume. The more blowdown, the more water replenishment. This energy-saving system is adaptive. By utilizing the waste heat of the boiler, the boiler water replenishment temperature can be increased and fuel consumption can be reduced; the boiler blowdown water temperature can be reduced, and the tap water consumption for cooling the blowdown cooling pool 6 can be reduced.
Claims
1. A recovery system utilizing waste heat from boiler exhaust, comprising at least one boiler, a water softener, a feed water tank and a blowdown cooling tank, wherein the boiler is equipped with a blowdown expansion tank, characterized in that: It also includes a heat exchange system, which includes at least a first heat exchanger and a second heat exchanger. The periodic sewage outlet of the boiler is connected to the sewage inlet of the first heat exchanger through a first periodic sewage pipe, the continuous sewage outlet of the boiler is connected to the sewage expansion tank through a first continuous sewage pipe, the water outlet of the sewage expansion tank is connected to the sewage inlet of the second heat exchanger through a second continuous sewage pipe, the sewage outlet of the first heat exchanger is connected to the sewage cooling pool through a second periodic sewage pipe, and the sewage outlet of the second heat exchanger is connected to the sewage cooling pool through a third continuous sewage pipe. The water inlet of the first heat exchanger and the water inlet of the second heat exchanger are respectively connected to the water softener through a softened water pipe, and the water softener is connected to a tap water pipe. The water outlet of the first heat exchanger and the water outlet of the second heat exchanger are respectively connected to the water feed tank through a softened return water pipe.
2. A recovery system utilizing waste heat from boiler exhaust according to claim 1, characterized in that: The softened water pipeline includes a first softened water pipeline and a second softened water pipeline, the softened return water pipeline includes a first softened return water pipeline and a second softened return water pipeline, the water softener is connected to the first softened water pipeline and the second softened water pipeline respectively through a tee, the water inlet of the first heat exchanger is connected to the first softened water pipeline, the water inlet of the second heat exchanger is connected to the second softened water pipeline, the water outlet of the first heat exchanger is connected to the second softened water pipeline, the water outlet of the second heat exchanger is connected to the water supply tank through the first softened return water pipeline, the second softened return water pipeline is connected between the second softened water pipeline and the first softened return water pipeline, the water inlet of the first heat exchanger is provided with a first on-off valve, and the water outlet is provided with a second on-off valve, the water inlet of the second heat exchanger is provided with a third on-off valve, and the water outlet is provided with a fourth on-off valve, the second softened water pipeline is provided with a fifth on-off valve, and the second softened return water pipeline is provided with a sixth on-off valve.
3. A recovery system utilizing waste heat from boiler exhaust according to claim 2, characterized in that: The first on-off valve, the second on-off valve, the third on-off valve, the fourth on-off valve, the fifth on-off valve and the sixth on-off valve are all ball valves.
4. A recovery system utilizing waste heat from boiler exhaust according to claim 1 or 2, characterized in that: The first periodic sewage discharge pipe, the second periodic sewage discharge pipe, the first continuous sewage discharge pipe, the second continuous sewage discharge pipe and the third continuous sewage discharge pipe are all provided with a seventh on-off valve, and the seventh on-off valve is a stop valve.
5. A recovery system utilizing waste heat from boiler exhaust according to claim 1 or 2, characterized in that: It also includes a sewage control system, which includes a sewage controller, a sewage control valve and a sensor. The sewage control valve and the sensor are both arranged on the first continuous sewage pipe. The sewage controller is electrically connected to the sensor and the sewage control valve respectively. The sensor is used to detect the conductivity of the sewage and send it to the sewage controller. The sewage controller controls the action of the sewage control valve.
6. A recovery system utilizing waste heat from boiler exhaust according to claim 1 or 2, characterized in that: The flash steam pipe at the top of the sewage expansion tank is connected to the water supply tank, and the flash steam pipe extends at least 300 mm below the lowest water level line in the sewage expansion tank. The lower section of the flash steam pipe below the water level line is provided with multiple rows of through holes.
7. A recovery system for utilizing waste heat from boiler exhaust according to claim 6, characterized in that: The spacing between each row of the plurality of rows of through holes is no more than 25 mm.
8. A recovery system utilizing waste heat from boiler exhaust according to claim 1 or 2, characterized in that: The flash steam pipeline at the top of the blowdown expansion tank is connected to the deaerator.