Multi-type waste heat recycling system

Abstract

The utility model discloses a multi-type waste heat recycling system, and belongs to the technical field of waste heat recycling. The device aims at solving the problem that the energy utilization efficiency of cigarette production is not high and comprises a deoxidizing and softening water tank, a stepped heat exchange unit and a boiler deaerator. A water outlet of the deoxidizing and softening water tank is respectively connected with a water return port of the deoxidizing and softening water tank and the boiler deaerator through the stepped heat exchange unit; the cascade heat exchange unit is connected with a boiler continuous blowdown flash steam pipeline, a condensate water recovery tank flash steam pipe, an air compression waste heat hot water pipeline and a boiler tail smoke pipeline. When softened water in the deoxidizing and softening water tank flows in the step heat exchange unit, the softened water is sequentially heated step by step through boiler continuous pollution discharge flash steam, condensate water recovery tank flash steam, air compression waste heat and boiler tail smoke and then enters the boiler deaerator and the deoxidizing and softening water tank. According to the deaerator, the temperature of softened water entering the deaerator can be raised from 25 DEG C to 85-95 DEG C, the energy utilization rate is improved, and meanwhile waste discharge pollution is reduced.

Description

Technical Field

[0001] This utility model relates to a multi-type waste heat recovery and utilization system, belonging to the field of waste heat recovery technology. Background Technology

[0002] In cigarette manufacturing, pharmaceutical and chemical, and power generation enterprises, atmospheric thermal spray deaerators are commonly used as deoxygenation equipment for boiler feedwater. Their main principle is to heat the softened water inside the deaerator to 104°C, maintaining a pressure of 0.02 MPa, at which point the dissolved oxygen level inside the deaerator is at its lowest. Therefore, maintaining this state requires a significant amount of steam to heat the softened water entering the deaerator from 25°C to 104°C.

[0003] Currently, most cigarette manufacturers use steam to heat the softened water in their deaerators. The steam energy consumption of deaerators accounts for 10-15% of the total steam energy consumption of cigarette manufacturers. The amount of high-quality steam consumed is large, resulting in high operating costs.

[0004] Meanwhile, in the steam production and use process of cigarette manufacturing enterprises, such as the continuous blowdown of boilers and the flash steam generated in the tobacco processing workshop, the waste heat generated by the air compressor during air compression (accounting for 60% of the air compressor's energy consumption), and the emission of high-temperature flue gas waste heat from the tail of the boiler into the air, not only wastes high-quality energy but also pollutes the surrounding environment.

[0005] There are relatively mature recovery technologies for the utilization of waste heat in boilers or other related equipment. However, the existing waste heat utilization technologies usually adopt a separate recovery method, and build a corresponding recovery system for each type of waste heat, which leads to low energy utilization efficiency. Secondly, the existing waste heat recovery system of cigarette factories has high equipment costs, maintenance and management costs. If any type of waste heat recovery equipment fails, it will affect the continuous supply of soft water to the deaerator. Utility Model Content

[0006] Purpose of the utility model: The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a multi-type waste heat recovery and utilization system that can solve the problems in the background technology mentioned above.

[0007] To solve the above-mentioned technical problems, this utility model is implemented using the following technical solution:

[0008] A multi-type waste heat recovery and utilization system includes a deaeration softening water tank, a cascade heat exchange unit, and a boiler deaerator;

[0009] The outlet of the deoxygenated softened water tank is connected to the return outlet of the deoxygenated softened water tank and the boiler deaerator through a stepped heat exchange unit.

[0010] The cascade heat exchange unit comprises a first heat exchange device, a second heat exchange device, a third heat exchange device and a fourth heat exchange device.

[0011] The first heat exchange device is connected with the continuous blowdown flash steam pipeline of the boiler and the deaerated softened water tank respectively, the second heat exchange device is connected with the first heat exchange device and the condensate recovery tank flash steam pipeline respectively, the third heat exchange device is connected with the second heat exchange device and the air compression waste heat hot water pipeline respectively, and the fourth heat exchange device is connected with the third heat exchange device and the boiler tail flue gas pipeline respectively.

[0012] When the softened water in the deaerated softened water tank flows in the cascade heat exchange unit, the softened water is sequentially heated by the continuous blowdown flash steam of the boiler, the condensate recovery tank flash steam, the air compression waste heat and the boiler tail flue gas, and then enters the deaerator of the boiler and the deaerated softened water tank.

[0013] Optionally, a plurality of bypass pipelines are arranged between the first heat exchange device, the second heat exchange device, the third heat exchange device and the fourth heat exchange device, wherein the plurality of bypass pipelines comprise a first bypass pipeline, a second bypass pipeline, a third bypass pipeline and a fourth bypass pipeline; a stop valve and an electric valve are arranged on the first bypass pipeline, the second bypass pipeline, the third bypass pipeline and the fourth bypass pipeline.

[0014] Optionally, the first heat exchange device comprises a first pipeline, a pressure gauge, a first stop valve assembly, a variable frequency circulating water pump, a check valve, a first temperature sensor and a first heat exchanger.

[0015] The water inlet of the first heat exchanger is connected with the water outlet of the deaerated softened water tank through the first pipeline, and the steam inlet of the first heat exchanger is connected with the continuous blowdown flash steam pipeline of the boiler.

[0016] The pressure gauge, the first stop valve assembly, the variable frequency circulating water pump, the check valve and the first temperature sensor are arranged on the first pipeline.

[0017] The water inlet and the water outlet of the first heat exchanger are connected with two ports of the first bypass pipeline respectively.

[0018] Optionally, the second heat exchange device comprises a second pipeline, a second stop valve assembly, a second temperature sensor and a second heat exchanger.

[0019] The water inlet of the second heat exchanger is connected with the water outlet of the first heat exchanger through the second pipeline, and the steam inlet of the second heat exchanger is connected with the condensate recovery tank flash steam pipeline; a flash steam electric valve is arranged on the flash steam pipeline.

[0020] The second stop valve assembly and the second temperature sensor are arranged on the second pipeline.

[0021] The water inlet and the water outlet of the second heat exchanger are connected with two ports of the second bypass pipeline respectively.

[0022] Optionally, the three-stage heat exchange device comprises a third pipeline, a three-stage stop valve assembly, a third temperature sensor and a third heat exchanger.

[0023] The first water inlet of the third heat exchanger is connected to the water outlet of the second heat exchanger through the third pipeline, and the second water inlet of the third heat exchanger is connected to the air pressure waste heat water pipe.

[0024] The three-stage stop valve assembly and the third temperature sensor are arranged on the third pipeline.

[0025] The first water inlet and the water outlet of the third heat exchanger are respectively connected to two ports of a third bypass pipeline.

[0026] Optionally, the four-stage heat exchange device comprises a fourth pipeline, a fifth pipeline, a four-stage stop valve assembly, a fourth temperature sensor, a fifth temperature sensor and a fourth heat exchanger.

[0027] The water inlet of the fourth heat exchanger is connected to the water outlet of the third heat exchanger through the fourth pipeline.

[0028] The gas inlet of the fourth heat exchanger is connected to the tail flue gas pipe of the boiler through a flue gas electric valve.

[0029] The water outlet of the fourth heat exchanger is connected to the backwater inlet of the deaerated softened water tank and the boiler deaerator through the fifth pipeline.

[0030] The four-stage stop valve assembly is arranged on the fourth pipeline and the fifth pipeline, and the fourth temperature sensor and the fifth temperature sensor are arranged on the fourth pipeline and the fifth pipeline, respectively.

[0031] The water inlet and the water outlet of the fourth heat exchanger are respectively connected to two ports of a fourth bypass pipeline.

[0032] Optionally, the water inlet of the deaerated softened water tank is connected to the sodium ion exchanger through a first water inlet electric valve.

[0033] The backwater inlet of the deaerated softened water tank is connected to the four-stage heat exchange device and the boiler deaerator through a seventh pipeline, and a backwater electric valve and a pressure sensor are arranged on the seventh pipeline.

[0034] A first liquid level sensor is arranged in the deaerated softened water tank to detect a liquid level signal of the deaerated softened water tank.

[0035] Optionally, the water inlet of the boiler deaerator is connected to a sixth pipeline, and a second water inlet electric valve is arranged on the sixth pipeline.

[0036] The sixth pipeline is further connected to the fifth pipeline and the seventh pipeline.

[0037] A second liquid level sensor is arranged in the boiler deaerator to detect a liquid level signal of the boiler deaerator.

[0038] Beneficial effects: Compared with the prior art, this utility model has the following advantages:

[0039] 1. The softened water flowing from the deaerator softened water tank is heated in stages through a cascade heat exchange unit. This fully utilizes the heat from the boiler's continuous blowdown flash steam, condensate recovery tank flash steam, compressed air waste heat, and boiler tail gas to circulate and heat the softened water entering the deaerator, raising its temperature from 25℃ to 85℃-95℃, thus saving a significant amount of high-quality steam. This greatly reduces boiler operating costs and avoids environmental pollution caused by waste heat emissions.

[0040] 2. Multiple bypass pipelines are installed in the cascade heat exchange unit. These bypass pipelines are connected in series with the primary, secondary, tertiary, and quaternary heat exchange units, and each is equipped with an independent shut-off valve and an electric valve. When any primary heat exchange unit malfunctions and requires maintenance, the multiple bypass pipelines can be opened to circulate soft water with other normally operating heat exchange units, ensuring a continuous supply of soft water to the deaerator. Attached Figure Description

[0041] Figure 1 The diagram shown is a structural schematic of the various types of waste heat recovery and utilization systems provided in this embodiment.

[0042] In the figure: 1 - deoxygenized soft water tank, 10 - first pipeline, 101 - pressure gauge, 102 - first primary stop valve, 103 - variable frequency circulating water pump, 104 - second primary stop valve, 105 - check valve, 106 - third primary stop valve, 107 - first temperature sensor, 120 - boiler continuous blowdown flash steam pipeline, 130 - condensate recovery tank flash steam pipe, 1301 - flash steam electric valve, 140 - air compression waste heat hot water pipeline, 150 - boiler tail flue gas pipeline, 1501 - flue gas electric valve, 160 - sodium ion exchanger, 1601 - first liquid level sensor, 1602 - first water inlet electric valve, 2 - first heat exchanger, 20 - second pipeline, 201 - second temperature sensor, 202 - first secondary stop valve, 203 - second secondary stop valve, 3 - second heat exchanger, 30 - third pipeline, 301 - third temperature sensor, 302 - first tertiary stop valve, 303 - second tertiary stop valve, 4 - third heat exchanger, 40 - fourth pipeline, 401 - first quaternary stop valve, 402 - second quaternary stop valve, 403 - fourth temperature sensor, 5 - fourth heat exchanger, 50 - fifth pipeline, 501 - third quaternary stop valve, 502 - fifth temperature sensor, 6 - boiler deaerator, 60 - sixth pipeline, 601 - second water inlet electric valve, 602 - second liquid level sensor, 70 - seventh pipeline, 701 - pressure sensor, 702 - backwater electric valve, 80 - first bypass pipeline, 801 - first bypass pipeline stop valve, 802 - first bypass pipeline electric valve, 90 - second bypass pipeline, 901 - second bypass pipeline stop valve, 902 - second bypass pipeline electric valve, 100 - third bypass pipeline, 1001 - third bypass pipeline stop valve, 1002 - third bypass pipeline electric valve, 110 - fourth bypass pipeline, 1101 - fourth bypass pipeline stop valve, 1102 - fourth bypass pipeline electric valve. DETAILED DESCRIPTION

[0043] The utility model will be described further, combined with the drawings. The following examples are only for more clearly explaining the technical scheme of the utility model, and cannot limit the protection scope of the utility model. EMBODIMENT

[0044] The embodiment provides a kind of multi-type waste heat recovery system, as shown in Figure 1 Including deoxygenized soft water tank 1, ladder heat exchange unit and boiler deaerator 6;The water outlet of deoxygenized soft water tank 1 is connected with the backwater port of deoxygenized soft water tank 1 and boiler deaerator 6 respectively by ladder heat exchange unit;Ladder heat exchange unit includes primary heat exchange device, secondary heat exchange device, tertiary heat exchange device and quaternary heat exchange device;

[0045] The first heat exchanger 2 in the primary heat exchange device is connected with the boiler continuous blowdown flash steam pipeline 120 and the deaerated softened water tank 1 respectively, the second heat exchanger 3 in the secondary heat exchange device is connected with the primary heat exchange device and the condensate recovery tank flash steam pipeline 130 respectively, the third heat exchanger 4 in the tertiary heat exchange device is connected with the secondary heat exchange device and the air compression waste heat hot water pipeline 140 respectively, and the fourth heat exchanger 5 in the quaternary heat exchange device is connected with the tertiary heat exchange device and the boiler tail flue gas pipeline 150 respectively.

[0046] The deaerated softened water tank 1 flows out the softened water at about 25℃, and the softened water flows through the primary heat exchange device, the secondary heat exchange device, the tertiary heat exchange device and the quaternary heat exchange device in turn to utilize the boiler continuous blowdown waste heat, the flash steam waste heat generated in the cuttage, the waste heat generated in the air compression process of the air compressor and the boiler tail high-temperature flue gas waste heat, so that the temperature of the softened water entering the deaerator is increased from 25℃ to 85℃-95℃, and a large amount of high-quality steam is saved. The boiler operation cost is greatly reduced, and the surrounding environmental pollution caused by waste heat emission is avoided. Embodiment

[0047] Based on the same technical concept as that in Embodiment 1, the embodiment provides a multi-type waste heat recovery system, and a plurality of bypass pipelines are arranged between the primary heat exchange device, the secondary heat exchange device, the tertiary heat exchange device and the quaternary heat exchange device. The plurality of bypass pipelines include a first bypass pipeline 80, a second bypass pipeline 90, a third bypass pipeline 100 and a fourth bypass pipeline 110. The first bypass pipeline 80 is provided with a first bypass pipeline stop valve 801 and a first bypass pipeline electric valve 802, the second bypass pipeline 90 is provided with a second bypass pipeline stop valve 901 and a second bypass pipeline electric valve 902, and the third bypass pipeline 100 is provided with a third bypass pipeline stop valve 1001 and a third bypass pipeline electric valve 1002. The fourth bypass pipeline 110 is provided with a fourth bypass pipeline stop valve 1101 and a fourth bypass pipeline electric valve 1102. When any heat exchange device of the cascade heat exchange unit is overhauled, the stop valve and the electric valve on the corresponding bypass pipeline are opened, so that the corresponding bypass pipeline is communicated with the next heat exchange device, thereby enabling the deaerated softened water tank 1 to continue to heat the softened water by using other heat exchange devices, and ensuring the continuous supply of the softened water of the deaerator.

[0048] Optionally, the primary heat exchange device includes a first pipeline 10, a pressure gauge 101, a primary stop valve assembly, a variable frequency circulating water pump 103, a check valve 105, a first temperature sensor 107 and a first heat exchanger 2. The water inlet of the first heat exchanger 2 is connected with the water outlet of the deaerated softened water tank 1 through the first pipeline 10, and the steam inlet of the first heat exchanger 2 is connected with the boiler continuous blowdown flash steam pipeline 120. The continuous blowdown waste heat can increase the temperature of the softened water of the waste heat recovery system by about 15℃.

[0049] Pressure gauge 101, primary shut-off valve assembly, variable frequency circulating water pump 103, check valve 105, and first temperature sensor 107 are installed on the first pipeline 10; wherein, the primary shut-off valve assembly includes a first primary shut-off valve 102, a second primary shut-off valve 104, and a third primary shut-off valve 106; the first primary shut-off valve 102 and the second primary shut-off valve 104 are respectively installed at the inlet and outlet of the variable frequency circulating water pump 103, and are used to cut off the flow of soft water through the first primary shut-off valve 102 and the second primary shut-off valve 104 when the variable frequency circulating water pump 103 is abnormal, so as to facilitate maintenance. A check valve 105 is located on one side of the second-stage shut-off valve 104 to prevent backflow of circulating water when the variable frequency circulating water pump 103 stops operating; a pressure gauge 101 is located between the first-stage shut-off valve 102 and the outlet of the deoxygenated softened water tank 1 to detect the water pressure flowing out of the deoxygenated softened water tank 1; a third-stage shut-off valve 106 and a first temperature sensor 107 are located at the connection section between the first bypass pipeline 80 and the inlet of the first heat exchanger 2. The third-stage shut-off valve 106 is used to cut off or connect the first heat exchanger 2, and the first temperature sensor 107 is used to detect the water temperature entering the first heat exchanger 2.

[0050] The inlet and outlet of the first heat exchanger 2 are connected to the two ports of the first bypass pipe 80 through the first pipe 10 and the second pipe 20, respectively. The first and second stage shut-off valves 202 and the second temperature sensor 201 are installed at the connection section between the outlet of the first heat exchanger 2 and the first bypass pipe 80. When the first heat exchanger 2 malfunctions and needs to be repaired, the third stage shut-off valve 106 and the first and second stage shut-off valves 202 are closed first, and then the first bypass pipe shut-off valve 801 and the first bypass pipe electric valve 802 are opened (normally closed when the first heat exchanger 2 is normal). This allows the water from the deaerator softening water tank 1 to be supplied to the secondary heat exchange device through the first bypass pipe 80, and then other types of waste heat utilization can be carried out. This structure can stably ensure the continuous supply of softened water to the deaerator during the maintenance of various types of waste heat equipment.

[0051] Optionally, the secondary heat exchange device includes a second pipeline 20, a secondary shut-off valve assembly, a second temperature sensor 201, and a second heat exchanger 3;

[0052] The inlet of the second heat exchanger 3 is connected to the outlet of the first heat exchanger 2 via a second pipeline 20; and the steam inlet of the second heat exchanger 3 is connected to the flash steam pipe 130 of the condensate recovery tank; a flash steam electric valve 1301 is installed on the flash steam pipe; a secondary shut-off valve assembly and a second temperature sensor 201 are installed on the second pipeline 20. The flash steam electric valve 1301 is electrically connected to a PID controller, and the opening of the flash steam electric valve 1301 is adjusted by the PID controller to ensure that the temperature of the softened water in the waste heat recovery system at the outlet of the second heat exchanger 3 is maintained at around 50℃-80℃. Therefore, this type of waste heat recovery utilizes the flash steam discharged into the air at the end of the silk-making workshop's production process as a heat source to heat the softened water through the second heat exchanger 3, which greatly increases the temperature of the softened water and avoids the pollution of the surrounding environment caused by the venting of flash steam.

[0053] The secondary shut-off valve assembly includes a first secondary shut-off valve 202 and a second secondary shut-off valve 203; the first secondary shut-off valve 202 and the second temperature sensor 201 are located at the connection section between the outlet of the first heat exchanger 2 and the first bypass pipe 80. The first secondary shut-off valve 202 is used to cut off or connect the outlet of the first heat exchanger 2, and the second temperature sensor 201 is used to detect the water temperature at the outlet of the first heat exchanger 2.

[0054] The inlet and outlet of the second heat exchanger 3 are connected to the two ports of the second bypass pipe 90 through the second pipe 20 and the third pipe 30, respectively. The first and third stage shut-off valves 302 and the third temperature sensor 301 are installed at the connection section between the outlet of the second heat exchanger 3 and the second bypass pipe 90. When the second heat exchanger 3 malfunctions and needs to be repaired, the second and third stage shut-off valves 203 and 302 are closed first, and then the second bypass pipe shut-off valve 901 and the second bypass pipe electric valve 902 are opened (normally closed when the second heat exchanger 3 is normal). This allows the water heated by the first heat exchanger 2 to be delivered to the tertiary heat exchanger through the second bypass pipe 90, thus avoiding the impact on the supply of softened water to the deaerator due to the malfunction of the second heat exchanger 3.

[0055] Optionally, the number of second heat exchangers 3 is not limited to one. Corresponding second heat exchangers 3 can be set at different flash steam discharge points, and multiple second heat exchangers 3 are connected in parallel in both the second pipeline 20 and the third pipeline 30.

[0056] Optionally, the three-stage heat exchange device includes a third pipeline 30, a three-stage shut-off valve assembly, a third temperature sensor 301, and a third heat exchanger 4;

[0057] The first inlet of the third heat exchanger 4 is connected to the outlet of the second heat exchanger 3 through the third pipe 30, and the second inlet of the third heat exchanger 4 is connected to the compressed air waste heat pipe. This type of waste heat recovery uses compressed air waste heat as a heat source to heat the softened water of the waste heat recovery system through the third heat exchanger 4, which not only increases the temperature of the softened water, but also avoids the pollution of the surrounding environment caused by the discharge of compressed air waste heat.

[0058] The three-stage shut-off valve assembly and the third temperature sensor 301 are installed on the third pipeline 30. The three-stage shut-off valve assembly includes a first three-stage shut-off valve 302 and a second three-stage shut-off valve 303. The first three-stage shut-off valve 302 and the third temperature sensor 301 are located at the connection section between the outlet of the second heat exchanger 3 and the second bypass pipeline 90. The first three-stage shut-off valve 302 is used to cut off or connect the outlet of the second heat exchanger 3. The third temperature sensor 301 is used to detect the water temperature at the outlet of the second heat exchanger 3. The third temperature sensor 301 is also electrically connected to the PID controller to provide real-time feedback on the water temperature at the outlet of the second heat exchanger 3 to the PID controller, so as to adjust the opening of the flash steam electric valve 1301 and achieve the purpose of real-time water temperature control of the second heat exchanger 3.

[0059] The first inlet and outlet of the third heat exchanger 4 are connected to the two ends of the third bypass pipe 100 via the third pipe 30 and the fourth pipe 40, respectively. The second and third stage shut-off valves 303 are installed at the connection between the inlet of the third heat exchanger 4 and the third bypass pipe 100, and the first and fourth stage shut-off valves 401 are installed at the connection between the outlet of the third heat exchanger 4 and the third bypass pipe 100. When the third heat exchanger 4 malfunctions and needs to be repaired, the second and third stage shut-off valves 303 and the first and fourth stage shut-off valves 401 are closed first, and then the third bypass pipe shut-off valve 1001 and the third bypass pipe electric valve 1002 are opened (normally closed when the third heat exchanger 4 is working properly). This allows the water heated by the second heat exchanger 3 to be supplied to the fourth stage heat exchanger through the third bypass pipe 100, thus preventing the continuous supply of softened water to the deaerator from being affected by the malfunction of the third heat exchanger 4.

[0060] Optionally, the four-stage heat exchange device includes a fourth pipeline 40, a fifth pipeline 50, a four-stage shut-off valve assembly, a fourth temperature sensor 403, a fifth temperature sensor 502, and a fourth heat exchanger 5.

[0061] The inlet of the fourth heat exchanger 5 is connected to the outlet of the third heat exchanger 4 via a fourth pipe 40; the air inlet of the fourth heat exchanger 5 is connected to the boiler tail flue gas pipe via a flue gas electric valve 1501; the outlet of the fourth heat exchanger 5 is connected to the return water inlet of the deaerator softened water tank 1 and the boiler deaerator 6 via a fifth pipe 50; both the flue gas electric valve 1501 and the fifth temperature sensor 502 are electrically connected to a PID controller. The PID controller adjusts the opening of the flue gas electric valve 1501 according to the temperature signal from the fifth temperature sensor 502 to stabilize the outlet temperature of the fourth heat exchanger 5. When the softened water outlet temperature of the fourth heat exchanger 5 reaches 95℃, the flue gas electric valve 1501 is activated to open the flue gas bypass to cool the fourth heat exchanger 5, ensuring that the softened water in the waste heat recovery system remains below 95℃ at the outlet temperature of the fourth heat exchanger 5. This type of waste heat recovery uses the tail gas emitted from the boiler as a heat source, and heats the softened water in the waste heat recovery system through the fourth heat exchanger 5, which greatly increases the temperature of the softened water and reduces the temperature of the boiler tail gas.

[0062] The four-stage shut-off valve assembly includes a first four-stage shut-off valve 401, a second four-stage shut-off valve 402, and a third four-stage shut-off valve 501.

[0063] The first and fourth stage shut-off valves 401, 402, and 403 are sequentially installed on the fourth pipeline 40; the fifth temperature sensor 502 and the third and fourth stage shut-off valves 501 are sequentially installed on the fifth pipeline 50; the second and fourth stage shut-off valves 402 and 403 are installed at the connection between the inlet of the fourth heat exchanger 5 and the fourth bypass pipeline 110; the fifth temperature sensor 502 and the third and fourth stage shut-off valves 501 are installed at the connection between the outlet of the fourth heat exchanger 5 and the fourth bypass pipeline 110. The connection section of pipe 110; when the fourth heat exchanger 5 malfunctions and needs maintenance, first close the second and fourth stage shut-off valves 402 and 501, then open the fourth bypass pipe shut-off valve 1101 and the fourth bypass pipe electric valve 1102 (normally closed when the fourth heat exchanger 5 is working properly), so that the water heated by the third heat exchanger 4 is supplied to the deaerator softening water tank 1 and the boiler deaerator 6 through the fourth bypass pipe, so as to avoid the continuous supply of softened water to the deaerator due to the malfunction of the fourth heat exchanger 5.

[0064] Optionally, the inlet of the deoxygenated softened water tank 1 is connected to the water supply pipeline of the sodium ion exchanger 160 of the water production equipment through the first inlet electric valve 1602; the first inlet electric valve 1602 is used to control the opening or closing of the inlet of the deoxygenated softened water tank 1, and the sodium ion exchanger 160 is used to replenish water to the deoxygenated softened water tank 1 after the first inlet electric valve 1602 is opened.

[0065] The return water inlet of the deoxygenated softened water tank 1 is connected to the fourth-stage heat exchange device and the boiler deaerator 6 through the seventh pipeline 70; and the seventh pipeline 70 is equipped with a return water electric valve 702 and a pressure sensor 701; the return water electric valve 702, the pressure sensor 701, and the variable frequency circulating water pump 103 are all connected to a PID controller, which is used to control the opening degree of the return water electric valve 702 and the speed of the variable frequency circulating water pump 103 according to the pressure signal fed back by the pressure sensor 701, so as to ensure that the pressure of the entire recovery system is stable at 0.4MPa, and at the same time ensure that the inlet water pressure of the deaerator is stable.

[0066] The deoxygenated softened water tank 1 is equipped with a first liquid level sensor 1601. The first liquid level sensor 1601 and the first inlet electric valve 1602 are electrically connected to the PID controller to monitor the liquid level signal of the deoxygenated softened water tank 1 and control the opening and closing status and opening degree of the first inlet electric valve 1602.

[0067] Optionally, the inlet of the boiler deaerator 6 is connected to the sixth pipeline 60, and the sixth pipeline 60 is equipped with a second inlet electric valve 601; the sixth pipeline 60 is also connected to the fifth pipeline 50 and the seventh pipeline 70; the boiler deaerator 6 is equipped with a second liquid level sensor 602 for detecting the liquid level signal of the boiler deaerator 6.

[0068] The second inlet electric valve 601 and the second liquid level sensor 602 are both electrically connected to the PID controller to monitor the liquid level signal of the boiler deaerator 6 and control the opening and closing status and opening degree of the second inlet electric valve 601, ultimately ensuring that the liquid level of the boiler deaerator 6 is stable within the set value of 130cm.

[0069] Working principle:

[0070] In practice, the deoxygenated softened water tank 1 flows softened water at about 25°C to the cascade heat exchange unit through the first pipeline 10. The first-stage shut-off valve assembly and the variable frequency circulating water pump 103 on the first pipeline 10 are both open, while the shut-off valves and electric valves of the multi-bypass pipelines are closed. The softened water at about 25°C enters the inlet of the first heat exchanger 2 through the third-stage shut-off valve 106. The steam inlet of the first heat exchanger 2 is connected to the boiler continuous blowdown flash steam pipeline 120. The continuous blowdown waste heat can raise the temperature of the softened water in the waste heat recovery system by about 15°C.

[0071] The softened water heated by the first heat exchanger flows from the outlet of the first heat exchanger 2 into the second pipeline 20, and then passes through the first secondary shut-off valve 202 and the second secondary shut-off valve 203 in sequence before entering the inlet of the second heat exchanger 3. The steam inlet of the second heat exchanger 3 is connected to the flash steam pipe 130 of the condensate recovery tank. The flash steam is used as a heat source to reheat the softened water flowing through the second heat exchanger 3, thereby raising the temperature of the softened water again and avoiding the pollution of the surrounding environment caused by the venting of flash steam.

[0072] The softened water heated by the second heat exchanger flows from the outlet of the second heat exchanger 3 into the third pipeline 30, and then passes through the first and third stage shut-off valves 302 and 303 in sequence before entering the inlet of the third heat exchanger 4. The second inlet of the third heat exchanger 4 is connected to the air compressor waste heat pipe, using the air compressor waste heat as a heat source to heat the softened water flowing through the third heat exchanger 4 for the third time, while avoiding the pollution of the surrounding environment caused by the air compressor waste heat being discharged into the air.

[0073] The softened water heated by the third heat exchanger flows from the outlet of the third heat exchanger 4 into the fourth pipeline 40, and then passes through the first and fourth stage shut-off valves 401 and 402 in sequence before entering the inlet of the fourth heat exchanger 5. The air inlet of the fourth heat exchanger 5 is connected to the flue gas pipe at the tail of the boiler through the flue gas electric valve 1501. The flue gas discharged from the boiler into the air is used as a heat source to heat the softened water flowing through the fourth heat exchanger 5 for the fourth time. When the fifth temperature sensor 502 detects that the temperature at the outlet of the fourth heat exchanger 5 reaches 95°C, the flue gas electric valve 1501 is activated to open the flue gas bypass and cool the fourth heat exchanger 5. This ensures that the temperature of the softened water in the waste heat recovery system is kept below 95°C at the outlet of the fourth heat exchanger 5, which greatly increases the temperature of the softened water and reduces the temperature of the flue gas at the tail of the boiler.

[0074] The softened water heated by the fourth heat exchanger flows from the outlet of the fourth heat exchanger 5 into the fifth pipeline 50. At this time, the softened water has undergone four stages of circulating heating, and the temperature of the softened water has risen from 25℃ to 85℃-95℃. It then enters the sixth pipeline 60 and the seventh pipeline 70 through the third and fourth stage shut-off valves 501 on the fifth pipeline 50. The softened water at 85℃-95℃ is divided into two streams and enters the deaerator and the deaerated softened water tank 1 respectively.

[0075] When any heat exchanger in the cascade heat exchange unit malfunctions or malfunctions, the shut-off valves connecting the inlet and bypass pipes of the malfunctioning heat exchanger and the outlet and bypass pipes are closed, and the shut-off valve and electric valve on the corresponding bypass pipe are opened, so that the corresponding bypass pipe is connected to the next stage heat exchange device. This allows the deaerator softened water tank 1 to continue to use other heat exchange devices to cascade circulate and heat the soft water, ensuring a continuous supply of softened water to the deaerator.

[0076] This invention utilizes a tiered heat exchange unit to circulate and heat the softened water flowing from the deaerator softened water tank 1. It fully leverages the heat from the boiler's continuous blowdown flash steam, condensate recovery tank flash steam, compressed air waste heat, and boiler tail gas to reheat the softened water in the deaerator. This raises the temperature of the softened water entering the deaerator from 25℃ to 85℃-95℃, saving a significant amount of high-quality steam. This greatly reduces boiler operating costs and avoids environmental pollution caused by waste heat emissions.

[0077] Multiple bypass pipelines are installed in the cascade heat exchange unit. These bypass pipelines are connected in series through the primary, secondary, tertiary, and quaternary heat exchange devices, and each is equipped with an independent shut-off valve and an electric valve. When any primary heat exchange device malfunctions and requires maintenance, the multiple bypass pipelines can be opened to circulate soft water with other normally operating heat exchange devices, ensuring a continuous supply of soft water to the deaerator.

[0078] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0079] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

Claims

1. A multi-type waste heat recovery and utilization system, characterized in that, This includes a deaerated softened water tank, a cascade heat exchange unit, and a boiler deaerator; The outlet of the deoxygenated softened water tank is connected to the return outlet of the deoxygenated softened water tank and the boiler deaerator through a stepped heat exchange unit. The cascade heat exchange unit includes a primary heat exchange device, a secondary heat exchange device, a tertiary heat exchange device, and a quaternary heat exchange device; The primary heat exchanger is connected to the boiler's continuous blowdown flash steam pipeline and the deaeration softened water tank; the secondary heat exchanger is connected to the primary heat exchanger and the flash steam pipeline of the condensate recovery tank; the tertiary heat exchanger is connected to the secondary heat exchanger and the compressed air waste heat hot water pipeline; and the quaternary heat exchanger is connected to the tertiary heat exchanger and the boiler's tail flue gas pipeline. When the softened water in the deoxygenated softened water tank flows in the stepped heat exchange unit, it is heated step by step by the continuous blowdown flash steam of the boiler, the flash steam of the condensate recovery tank, the waste heat of the compressed air and the flue gas at the tail end of the boiler before entering the boiler deaerator and the deoxygenated softened water tank.

2. The multi-type waste heat recovery and utilization system according to claim 1, characterized in that, Multiple bypass pipelines are provided between the primary heat exchanger, the secondary heat exchanger, the tertiary heat exchanger, and the quaternary heat exchanger; wherein, the multiple bypass pipelines include a first bypass pipeline, a second bypass pipeline, a third bypass pipeline, and a fourth bypass pipeline; each of the first bypass pipeline, the second bypass pipeline, the third bypass pipeline, and the fourth bypass pipeline is equipped with a shut-off valve and an electric valve.

3. The multi-type waste heat recovery and utilization system according to claim 2, characterized in that, The primary heat exchange device includes a first pipeline, a pressure gauge, a primary shut-off valve assembly, a variable frequency circulating water pump, a check valve, a first temperature sensor, and a first heat exchanger. The inlet of the first heat exchanger is connected to the outlet of the deaerated softened water tank through the first pipeline, and the steam inlet of the first heat exchanger is connected to the boiler continuous blowdown flash steam pipeline. The pressure gauge, primary shut-off valve assembly, variable frequency circulating water pump, check valve, and temperature sensor are installed on the first pipeline. The inlet and outlet of the first heat exchanger are connected to the two ends of the first bypass pipeline, respectively.

4. The multi-type waste heat recovery and utilization system according to claim 2, characterized in that, The secondary heat exchange device includes a second pipeline, a secondary shut-off valve assembly, a second temperature sensor, and a second heat exchanger. The inlet of the second heat exchanger is connected to the outlet of the first heat exchanger via a second pipeline; and the steam inlet of the second heat exchanger is connected to the flash steam pipe of the condensate recovery tank; the flash steam pipe is equipped with a flash steam electric valve. The secondary shut-off valve assembly and the second temperature sensor are installed on the second pipeline; The inlet and outlet of the second heat exchanger are connected to the two ends of the second bypass pipeline, respectively.

5. The multi-type waste heat recovery and utilization system according to claim 2, characterized in that, The three-stage heat exchange device includes a third pipeline, a three-stage shut-off valve assembly, a third temperature sensor, and a third heat exchanger. The first inlet of the third heat exchanger is connected to the outlet of the second heat exchanger through a third pipeline, and the second inlet of the third heat exchanger is connected to the waste heat pipe of the air pressure. The three-stage shut-off valve assembly and the third temperature sensor are installed on the third pipeline; The first inlet and outlet of the third heat exchanger are respectively connected to the two ends of the third bypass pipeline.

6. The multi-type waste heat recovery and utilization system according to claim 2, characterized in that, The four-stage heat exchange device includes a fourth pipeline, a fifth pipeline, a four-stage shut-off valve assembly, a fourth temperature sensor, a fifth temperature sensor, and a fourth heat exchanger. The inlet of the fourth heat exchanger is connected to the outlet of the third heat exchanger via a fourth pipeline; The inlet of the fourth heat exchanger is connected to the flue gas pipe at the tail of the boiler via an electric flue gas valve. The outlet of the fourth heat exchanger is connected to the return outlet of the deaerated softened water tank and the boiler deaerator via the fifth pipeline. The four-stage shut-off valve assembly is distributed on the fourth and fifth pipelines; the fourth and fifth temperature sensors are respectively installed on the fourth and fifth pipelines. The inlet and outlet of the fourth heat exchanger are connected to the two ends of the fourth bypass pipeline, respectively.

7. The multi-type waste heat recovery and utilization system according to claim 6, characterized in that, The inlet of the deoxygenated softened water tank is connected to the sodium ion exchanger via the first inlet electric valve. The return water inlet of the deoxygenated softened water tank is connected to the fourth-stage heat exchange device and the boiler deaerator through the seventh pipeline; and the seventh pipeline is equipped with a return water electric valve and a pressure sensor. The deoxygenated softened water tank is equipped with a first liquid level sensor for detecting the liquid level signal of the deoxygenated softened water tank.

8. The multi-type waste heat recovery and utilization system according to claim 7, characterized in that, The inlet of the boiler deaerator is connected to the sixth pipeline, and the sixth pipeline is equipped with a second inlet electric valve; The sixth pipeline is also connected to the fifth and seventh pipelines; The boiler deaerator is equipped with a second liquid level sensor for detecting the liquid level signal of the boiler deaerator.

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