Heat recovery system

Abstract

The utility model discloses a heat recovery system. The heat recovery system comprises a first heat exchange assembly used for conducting sensible heat recovery on smoke of the aluminum oxide roasting furnace; the flue gas pipeline is communicated with the roasting furnace and the first heat exchange assembly; the first conveying pipeline communicates with the first heat exchange assembly; the bypass flue is communicated with the flue gas pipeline and the first conveying pipeline; the adjusting valve is arranged in the bypass flue and used for adjusting the opening degree of the bypass flue; the chimney is communicated with the first conveying pipeline; and the second heat exchange assembly communicates with the chimney and is used for conducting latent heat recovery on the flue gas subjected to sensible heat recovery through the first heat exchange assembly.

Description

Technical Field

[0001] This application belongs to the field of heat exchange technology, specifically relating to a heat recovery system. Background Technology

[0002] Aluminum hydroxide roasting is the final processing step in alumina production. It involves drying the aluminum hydroxide filter cake obtained from decomposition filtration in a gas suspension roasting device to remove adhering water, deeply heating it to remove crystal water, and undergoing a crystal transformation to produce the final product, alumina. Aluminum hydroxide roasting is a crucial step in alumina production and one of the most energy-intensive processes.

[0003] The calcination process of aluminum hydroxide is essentially a dehydration process. Dry aluminum hydroxide contains approximately 38% water, plus an additional 5% of water adhering to its surface. Therefore, the calcination of aluminum hydroxide essentially removes about 43% of the water. Consequently, the calcination process inevitably requires a large amount of energy.

[0004] The calcination of aluminum hydroxide produces flue gas. This flue gas still contains a large amount of water vapor and heat, and the heat energy from this water vapor and heat cannot be recovered and utilized, resulting in a significant waste of resources. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides a heat recovery system, which aims to at least partially solve the technical problem of waste caused by the failure to recover and utilize the heat energy of the flue gas generated during the calcination of aluminum hydroxide.

[0006] The technical solution of this utility model is as follows:

[0007] A heat recovery system, characterized in that it comprises: a first heat exchange component for recovering sensible heat from flue gas in an alumina calcining furnace; a flue gas duct connected to the calcining furnace and the first heat exchange component; a first conveying duct connected to the first heat exchange component; a bypass flue connected to the flue gas duct and the first conveying duct; a regulating valve disposed in the bypass flue for adjusting the opening degree of the bypass flue; a chimney connected to the first conveying duct; and a second heat exchange component connected to the chimney for recovering latent heat from the flue gas after sensible heat recovery by the first heat exchange component.

[0008] In some embodiments, the first heat exchange assembly includes: a first heat exchanger having a first air inlet, a first air outlet, a first liquid inlet, and a first liquid outlet, wherein the first air inlet is connected to the flue gas duct, and the first air outlet is connected to the first conveying duct; a first heat exchange pipe connected to the first liquid inlet and the first liquid outlet; at least one heat transfer medium water circulation pump disposed on the first heat exchange pipe; a second heat exchanger including a second heat exchange pipe and a third heat exchange pipe spaced apart from the second heat exchange pipe, wherein the second heat exchange pipe has a second liquid inlet and a second liquid outlet, both of which are connected to the first heat exchange pipe; and at least one pressure pump disposed on the third heat exchange pipe.

[0009] In some implementations, the first heat exchange assembly further includes: a water supply tank; a water supply pipe connected to the water supply tank and the first heat exchange pipe; and a flow meter disposed on the first heat exchange pipe for detecting the flow rate of the liquid in the first heat exchange pipe.

[0010] In some implementations, the first heat exchange component further includes: a first temperature detector, disposed in the first heat exchange pipe and located at the first liquid outlet; wherein, if the first temperature value detected by the first temperature detector is less than the first set temperature value, the operating power of the heat transfer fluid circulation pump is reduced, and if the first temperature value detected by the first temperature detector is greater than the first set temperature value, the operating power of the heat transfer fluid circulation pump is increased.

[0011] In some implementations, the heat recovery system further includes a first fan disposed within the first conveying pipeline.

[0012] In some embodiments, a dust collector is provided between the roasting furnace and the first heat exchange component, the dust collector having a zero-pressure point, and the heat recovery system further includes a pressure detector for detecting the pressure at the zero-pressure point; wherein, if the pressure at the zero-pressure point detected by the pressure detector is positive, the operating frequency of the fan is increased, and if the pressure at the zero-pressure point detected by the pressure detector is negative, the operating frequency of the fan is decreased.

[0013] In some embodiments, the second heat exchange assembly includes: a third heat exchanger having a second air inlet, a second air outlet, a third liquid inlet, and a third liquid outlet, wherein the third liquid inlet is located between the second air inlet and the second air outlet, and the second air inlet is located between the third liquid inlet and the third liquid outlet; a second conveying pipe communicating with the chimney and the second air inlet; a fourth heat exchange pipe communicating with the third liquid inlet and the third liquid outlet; and a fourth heat exchanger including a fifth heat exchange pipe and a sixth heat exchange pipe spaced apart from the fifth heat exchange pipe, wherein the fifth heat exchange pipe has a fourth liquid inlet and a fourth liquid outlet, both of which are communicating with the fourth heat exchange pipe.

[0014] In some embodiments, the second heat exchange assembly includes: a fifth heat exchanger located between the fourth heat exchanger and the third inlet, the fifth heat exchanger including a seventh heat exchange pipe and an eighth heat exchange pipe spaced apart from the seventh heat exchange pipe, the seventh heat exchange pipe having a fifth inlet and a fifth outlet, both of the fifth inlet and the fifth outlet being connected to the fourth heat exchange pipe.

[0015] In some embodiments, the third heat exchanger has a sixth liquid outlet located between the second air inlet and the sixth liquid outlet, and the second heat exchange assembly further includes a condensate recovery pipe connected to the sixth liquid outlet.

[0016] In some embodiments, the second heat exchange assembly further includes a second fan disposed within the second delivery pipe.

[0017] The beneficial effects of this utility model include at least the following:

[0018] Since the first heat exchange component is used to recover sensible heat from the flue gas of the alumina calcining furnace, the flue gas pipeline is connected to the calcining furnace and the first heat exchange component, the first conveying pipeline is connected to the first heat exchange component, the chimney is connected to the first conveying pipeline, and the second heat exchange component is connected to the chimney. This second heat exchange component is used to recover latent heat from the flue gas after sensible heat recovery by the first heat exchange component. Therefore, the flue gas generated by the calcining furnace can be conveyed to the first heat exchange component through the flue gas pipeline. The first heat exchange component exchanges heat with the flue gas to reduce its temperature. Simultaneously, the first heat exchange component can use the heat from the flue gas to heat the medium (filtrate, etc.) required in the alumina calcining process, thus achieving sensible heat recovery from the flue gas of the alumina calcining furnace. The flue gas after sensible heat recovery by the first heat exchange component is then... The first conveying pipeline delivers the flue gas into the chimney. Part of the flue gas inside the chimney can enter the second heat exchange component, where it exchanges heat to lower the flue gas temperature. Simultaneously, the second heat exchange component can use the heat from the flue gas to heat the medium (such as greywater) required during the aluminum hydroxide roasting process. This achieves the recovery of latent heat from the flue gas in the alumina roasting furnace, reducing steam consumption in the original aluminum hydroxide roasting process, thus achieving energy conservation and emission reduction. It fully utilizes the waste heat of the flue gas, resulting in good economic and social benefits. Furthermore, it reduces thermal pollution, carbon dioxide and particulate matter emissions, and protects the environment. Through the tiered utilization of waste heat resources from the flue gas, the waste heat contained in the roasting furnace flue gas can be fully recovered and utilized, maximizing the recovery benefits.

[0019] Since the bypass flue is connected to both the flue gas duct and the first conveying duct, and a regulating valve is located within the bypass flue to adjust its opening, the regulating valve can be operated according to production requirements to adjust the opening of the bypass flue, thereby regulating the flue gas flow rate through the first heat exchange component. In other words, when the flue gas flow rate through the first heat exchange component is too high, the regulating valve is operated to increase the opening of the bypass flue, increasing the amount of flue gas entering the bypass flue from the flue gas duct. This, in turn, increases the amount of flue gas entering the first heat exchange component from the flue gas duct. The gas flow rate will decrease to prevent the heat exchange temperature of the first heat exchange component from becoming too high, which would cause the temperature of the heat exchange medium inside the first heat exchange component to become too high. When the flue gas flow rate through the first heat exchange component is too low, the regulating valve is operated to reduce the opening of the bypass flue, thereby reducing the amount of flue gas entering the bypass flue from the flue gas pipe. As a result, the amount of flue gas entering the first heat exchange component from the flue gas pipe will increase, thus preventing the heat exchange temperature of the first heat exchange component from becoming too low, which would cause the temperature of the heat exchange medium inside the first heat exchange component to become too low, and ensuring that the heat exchange process proceeds normally. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the first heat exchange component of a heat recovery system according to some embodiments;

[0022] Figure 2 This is a schematic diagram of the structure of the second heat exchange component of a heat recovery system according to some embodiments.

[0023] In the attached image:

[0024] First heat exchange component 10, first heat exchanger 11, first heat exchange pipe 12, heat medium water circulation pump 13, second heat exchanger 14, second heat exchange pipe 141, third heat exchange pipe 142, pressurization pump 15, water supply tank 16, water supply pipe 17, flow meter 18.

[0025] Flue gas duct 20;

[0026] First conveying pipeline 30;

[0027] Bypass flue 40;

[0028] Control valve 50;

[0029] Chimney 60;

[0030] Second heat exchange component 70, third heat exchanger 71, second air inlet 711, second air outlet 712, third liquid inlet 713, third liquid outlet 714, sixth liquid outlet 715, second conveying pipe 72, fourth heat exchange pipe 73, fourth heat exchanger 74, fifth heat exchange pipe 741, sixth heat exchange pipe 742, fifth heat exchanger 75, seventh heat exchange pipe 751, eighth heat exchange pipe 752, condensate recovery pipe 76, spray water circulation pump 77, second fan 78;

[0031] First fan 80. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] It should be noted that all directional indications in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0034] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0035] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0036] This application is described below with reference to the accompanying drawings and specific embodiments:

[0037] The heat recovery system provided in this embodiment aims to at least partially solve the technical problem of waste caused by the failure to recover and utilize the heat energy of the flue gas generated during the roasting of aluminum hydroxide.

[0038] Figure 1 This is a schematic diagram of the structure of the first heat exchange component of a heat recovery system according to some embodiments; Figure 2 This is a schematic diagram of the structure of the second heat exchange component of a heat recovery system according to some embodiments. (Combined with...) Figure 1 and Figure 2The heat recovery system of this application embodiment includes: a first heat exchange component 10, a flue gas duct 20, a first conveying duct 30, a bypass flue 40, a regulating valve 50, a chimney 60, and a second heat exchange component 70. The first heat exchange component 10 is used to recover sensible heat from the flue gas of the alumina calcining furnace. The flue gas duct 20 is connected to the calcining furnace and the first heat exchange component 10. The first conveying duct 30 is connected to the first heat exchange component 10. The bypass flue 40 is connected to the flue gas duct 20 and the first conveying duct 30. The regulating valve 50 is located in the bypass flue 40 and is used to regulate the opening degree of the bypass flue 40. The chimney 60 is connected to the first conveying duct 30. The second heat exchange component 70 is connected to the chimney 60 and is used to recover latent heat from the flue gas after sensible heat recovery by the first heat exchange component 10.

[0039] Flue gas passing through the bypass flue 40 can enter the chimney 60 through the first conveying pipe 30.

[0040] The temperature of the flue gas after heat exchange by the first heat exchange component 10 can be reduced from 180℃ to 100℃~120℃.

[0041] The temperature of the flue gas after heat exchange by the second heat exchange component 70 can be reduced from 180℃ to below 40℃.

[0042] Since the first heat exchange component 10 is used to recover sensible heat from the flue gas of the alumina calcining furnace, the flue gas pipe 20 is connected to the calcining furnace and the first heat exchange component 10, the first conveying pipe 30 is connected to the first heat exchange component 10, the chimney 60 is connected to the first conveying pipe 30, and the second heat exchange component 70 is connected to the chimney 60, and is used to recover latent heat from the flue gas after sensible heat recovery by the first heat exchange component 10, the flue gas generated by the calcining furnace can be conveyed to the first heat exchange component 10 through the flue gas pipe 20. The first heat exchange component 10 exchanges heat with the flue gas to reduce its temperature. At the same time, the first heat exchange component 10 can use the heat from the flue gas to heat the medium (filtrate, etc.) required in the alumina calcining process, thus realizing the recovery of sensible heat from the flue gas of the alumina calcining furnace. The recovered flue gas is transported to the chimney 60 through the first conveying pipe 30. Part of the flue gas in the chimney 60 can enter the second heat exchange component 70, where heat is exchanged to reduce the temperature of the flue gas. At the same time, the second heat exchange component 70 can use the heat of the flue gas to heat the medium (such as greywater) required in the aluminum hydroxide roasting process, realizing the recovery of latent heat of the flue gas from the alumina roasting furnace. This reduces the steam consumption required in the original aluminum hydroxide roasting process, achieving the goal of energy saving and consumption reduction. It makes full use of the waste heat of the flue gas, which has good economic and social benefits. At the same time, it can reduce thermal pollution, reduce carbon dioxide and dust emissions, and protect the environment. Through the cascade utilization of the waste heat resources of the flue gas, the waste heat contained in the roasting furnace flue gas can be fully recovered and utilized, maximizing the recovery benefits.

[0043] Since the bypass flue 40 is connected to the flue gas duct 20 and the first conveying duct 30, and the regulating valve 50 is located inside the bypass flue 40 to regulate its opening, the regulating valve 50 can be operated according to production requirements to adjust the opening of the bypass flue 40, thereby regulating the flue gas flow rate through the first heat exchange component 10. In other words, when the flue gas flow rate through the first heat exchange component 10 is too high, the regulating valve 50 is operated to increase the opening of the bypass flue 40, thus increasing the amount of flue gas entering the bypass flue 40 from the flue gas duct 20. This, in turn, increases the amount of flue gas entering the first heat exchange component from the flue gas duct 20. The amount of flue gas in the first heat exchange component 10 will decrease to prevent the heat exchange temperature of the first heat exchange component 10 from being too high, which would cause the temperature of the heat exchange medium in the first heat exchange component 10 to be too high. When the flue gas flow rate through the first heat exchange component 10 is too low, the regulating valve 50 is operated to reduce the opening of the bypass flue 40, so that the amount of flue gas entering the bypass flue 40 in the flue gas pipe 20 is reduced. Then, the amount of flue gas entering the first heat exchange component 10 in the flue gas pipe 20 will increase, so as to prevent the heat exchange temperature of the first heat exchange component 10 from being too low, which would cause the temperature of the heat exchange medium in the first heat exchange component 10 to be too low, and to ensure that the heat exchange process proceeds normally.

[0044] Combination Figure 1 In some embodiments, to ensure the normal operation of the heat exchange process, the first heat exchange assembly 10 includes: a first heat exchanger 11, a first heat exchange pipe 12, a heat transfer medium water circulation pump 13, a second heat exchanger 14, and a pressurizing pump 15. The first heat exchanger 11 has a first air inlet, a first air outlet, a first liquid inlet, and a first liquid outlet. The first air inlet is connected to the flue gas pipe 20, and the first air outlet is connected to the first conveying pipe 30. The first heat exchange pipe 12 is connected to the first liquid inlet and the first liquid outlet. At least one heat transfer medium water circulation pump 13 is located in the first heat exchange pipe 12. The second heat exchanger 14 includes a second heat exchange pipe 141 and a third heat exchange pipe 142 spaced apart from the second heat exchange pipe 141. The second heat exchange pipe 141 has a second liquid inlet and a second liquid outlet, both of which are connected to the first heat exchange pipe 12. At least one pressurizing pump 15 is located in the third heat exchange pipe 142.

[0045] In some embodiments, flue gas in flue gas duct 20 enters the first heat exchanger 11 through the first air inlet and enters the first conveying pipe 30 through the first air outlet. The heat medium water circulation pump 13 is started, so that heat medium water (evaporated qualified water) enters the first heat exchanger 11 through the first heat exchange pipe 12 and the first liquid inlet, so that the heat medium water can exchange heat with the flue gas. After heat exchange, the heat medium water enters the first heat exchange pipe 12 through the first liquid outlet and enters the second heat exchange pipe 141 through the first heat exchange pipe 12. The pressurization pump 15 is started, and the pressurization pump delivers the medium required in the aluminum hydroxide roasting process (filter press filtrate, etc.) to the third heat exchange pipe 142. The medium in the third heat exchange pipe 142 exchanges heat with the heat medium water in the second heat exchange pipe 141 to achieve heat exchange. The heat medium water in the second heat exchange pipe 141 enters the first heat exchange pipe 12 so that the heat medium water can be circulated.

[0046] In some embodiments, the number of heat medium water circulation pumps 13 can be one or more. When there are multiple heat medium water circulation pumps 13, one of the multiple heat medium water circulation pumps 13 is in operation, and the rest are on standby, so as to ensure that the heat exchange process can proceed normally.

[0047] In some embodiments, the number of pressurizing pumps 15 can be one or more. When there are multiple pressurizing pumps 15, one of the multiple pressurizing pumps 15 is in operation, and the rest are on standby, so as to ensure that the heat exchange process can proceed normally.

[0048] In some embodiments, the first heat exchanger 11 may be a radially jacketed heat pipe heat exchanger, and the second heat exchanger 14 may be a plate heat exchanger.

[0049] Combination Figure 1 In some embodiments, during the heat exchange process between the heat transfer medium water and the flue gas, the heat transfer medium water may be lost. To replenish the heat transfer medium water, the first heat exchange assembly 10 further includes a water supply tank 16, a water supply pipe 17, and a flow meter 18. The water supply pipe 17 is connected to the water supply tank 16 and the first heat exchange pipe 12. The flow meter 18 is located in the first heat exchange pipe 12 and is used to detect the flow rate of the liquid in the first heat exchange pipe 12.

[0050] In some embodiments, the flow rate of the liquid in the first heat exchange pipe 12 is detected by the flow meter 18. When the flow rate is lower than a set flow rate value, the water supply tank 16 replenishes the heat transfer medium water into the first heat exchange pipe 13 through the water supply pipe 17. A valve may be installed on the water supply pipe 17 to control the opening and closing of the water supply pipe 17.

[0051] In some embodiments, to ensure heat exchange efficiency, the first heat exchange assembly 10 further includes a first temperature detector. The first temperature detector is disposed on the first heat exchange pipe 12 and located at the first liquid outlet. If the first temperature value detected by the first temperature detector is less than a first set temperature value, the operating power of the heat transfer fluid circulation pump 13 is reduced; if the first temperature value detected by the first temperature detector is greater than the first set temperature value, the operating power of the heat transfer fluid circulation pump 13 is increased.

[0052] If the first temperature value detected by the first temperature detector is lower than the first set temperature value, it indicates that the heat transfer water in the first heat exchange pipe 12 has too short a residence time in the first heat exchanger 11, resulting in insufficient heat exchange capacity. Therefore, the operating power of the heat transfer water circulation pump 13 is reduced to increase the residence time of the heat transfer water in the first heat exchanger 11, allowing the heat transfer water to fully exchange heat with the flue gas. If the first temperature value detected by the first temperature detector is higher than the first set temperature value, it indicates that the heat transfer water in the first heat exchange pipe 12 has too long a residence time in the first heat exchanger 11, resulting in excessive heat exchange capacity and excessively high heat transfer water temperature, causing the heat transfer water to boil and affecting safety. Therefore, the operating power of the heat transfer water circulation pump 13 is increased to reduce the residence time of the heat transfer water in the first heat exchanger 11, allowing the heat transfer water to quickly leave the first heat exchanger 11.

[0053] In some embodiments, if the first temperature value detected by the first temperature detector is less than the first set temperature value, the opening of the bypass flue 40 is reduced, thereby reducing the amount of flue gas entering the bypass flue 40 from the flue gas pipe 20. This allows the flue gas from the flue gas pipe 20 to enter the first heat exchanger 11 as much as possible, ensuring sufficient heat exchange between the flue gas and the heat transfer medium in the first heat exchanger 11 and guaranteeing the heat exchange effect. If the first temperature value detected by the first temperature detector is greater than the first set temperature value, the opening of the bypass flue 40 is increased, thereby increasing the amount of flue gas entering the bypass flue 40 from the flue gas pipe 20. This reduces the amount of flue gas entering the first heat exchanger 11 from the flue gas pipe 20, preventing the heat transfer medium from overheating and boiling, which could compromise safety.

[0054] In some embodiments, the heat recovery system further includes an alarm. The alarm sounds when a first temperature value detected by the first temperature detector is less than a first set temperature value, and when the first temperature value detected by the first temperature detector is greater than the first set temperature value. The alarm may be a buzzer and / or a flashing light.

[0055] Combination Figure 1In some embodiments, in order to draw flue gas to the first heat exchanger 11 and the first conveying pipe 30, the heat recovery system further includes a first fan 80. The first fan 80 is located inside the first conveying pipe 30. When the fan 80 is activated, the flue gas in the flue gas duct 20 passes through the first heat exchanger 11 and enters the first conveying pipe 30.

[0056] In some embodiments, to ensure that the pressure inside the calcining furnace remains normal, a dust collector is provided between the calcining furnace and the first heat exchange component 10. The dust collector has a zero-pressure point, and the heat recovery system further includes a pressure detector. The pressure detector is used to detect the pressure at the zero-pressure point. If the pressure detector detects a positive pressure at the zero-pressure point, the operating frequency of the fan is increased; if the pressure detector detects a negative pressure at the zero-pressure point, the operating frequency of the fan is decreased to ensure the normal operation of the calcining furnace.

[0057] Combination Figure 2 In some embodiments, to ensure the normal operation of the heat exchange process, the second heat exchange assembly 70 includes: a third heat exchanger 71, a second conveying pipe 72, a fourth heat exchange pipe 73, and a fourth heat exchanger 74. The third heat exchanger 71 has a second air inlet 711, a second air outlet 712, a third liquid inlet 713, and a third liquid outlet 714. The third liquid inlet 713 is located between the second air inlet 711 and the second air outlet 712, and the second air inlet 711 is located between the third liquid inlet 713 and the third liquid outlet 714. The second conveying pipe 72 is connected to the chimney 60 and the second air inlet 711. The fourth heat exchange pipe 73 is connected to the third liquid inlet 713 and the third liquid outlet 714. The fourth heat exchanger 74 includes a fifth heat exchange pipe 741 and a sixth heat exchange pipe 742 spaced apart from the fifth heat exchange pipe 741. The fifth heat exchange pipe 741 has a fourth liquid inlet and a fourth liquid outlet, both of which are connected to the fourth heat exchange pipe 73.

[0058] After sensible heat recovery by the first heat exchange component 10, the flue gas is transported to the chimney 60 through the first conveying pipe 30. Part of the flue gas in the chimney 60 can enter the third heat exchanger 71 through the second conveying pipe 72 and the second air inlet 711. At this time, water in the third heat exchange pipe 73 enters the third heat exchanger 71 through the third liquid inlet 713 to exchange heat with the flue gas in the third heat exchanger 71. The heat-exchanged flue gas is discharged through the second air outlet 712, and the heat-exchanged water enters the third heat exchanger 71 through the third liquid outlet 714. In the fourth heat exchange pipe 73, the water after heat exchange enters the fifth heat exchange pipe 741 through the fourth inlet, and the medium (such as water) required for the aluminum hydroxide roasting process is introduced into the sixth heat exchange pipe 742, so that the medium in the sixth heat exchange pipe 742 exchanges heat with the water in the fifth heat exchange pipe 741 to heat the medium in the sixth heat exchange pipe 742, thus making full use of the heat. The water after heat exchange in the fifth heat exchange pipe 741 enters the fourth heat exchange pipe 73 through the fourth outlet to achieve circulation.

[0059] Combination Figure 2 In some embodiments, in order to achieve water circulation for the third heat exchanger 71, the second heat exchange assembly 70 includes a spray water circulation pump 77. The spray water circulation pump 77 is located in the fourth heat exchange pipe 73. Activating the spray water circulation pump 77 causes water to circulate within the fourth heat exchange pipe 74.

[0060] In some embodiments, to ensure heat exchange efficiency, the second heat exchange assembly 70 further includes a second temperature detector. The second temperature detector is disposed in the fourth heat exchange pipe 73 and located at the third liquid outlet 714. If the second temperature value detected by the second temperature detector is lower than the second set temperature value, the operating power of the spray water circulation pump 77 is reduced; if the second temperature value detected by the second temperature detector is higher than the second set temperature value, the operating power of the spray water circulation pump 77 is increased.

[0061] When the second temperature value detected by the second temperature detector is lower than the second set temperature value, it indicates that the water in the fourth heat exchange pipe 73 has stayed in the second heat exchanger 71 for too short a time, resulting in insufficient heat exchange. Therefore, the operating power of the spray water circulation pump 77 is reduced to increase the residence time of the water in the third heat exchanger 71, so that the water can fully exchange heat with the flue gas. When the second temperature value detected by the second temperature detector is higher than the second set temperature value, it indicates that the water in the fourth heat exchange pipe 73 has stayed in the second heat exchanger 71 for too long, resulting in excessive heat exchange, causing the water temperature to be too high, leading to boiling and affecting safety. Therefore, the operating power of the spray water circulation pump 77 is increased to reduce the residence time of the water in the third heat exchanger 71, so that the water leaves the third heat exchanger 71 quickly.

[0062] In some embodiments, the alarm sounds when the second temperature value detected by the second temperature detector is less than the second set temperature value, and the alarm sounds when the second temperature value detected by the second temperature detector is greater than the second set temperature value.

[0063] In some embodiments, the third heat exchanger 71 may be a swirling film flow two-phase heat exchanger.

[0064] Combination Figure 2 In some embodiments, to achieve sufficient heat exchange of the water in the fourth heat exchange pipe 73, the second heat exchange assembly 70 includes a fifth heat exchanger 75. The fifth heat exchanger 75 is located between the fourth heat exchanger 74 and the third liquid inlet 713. The fifth heat exchanger 75 includes a seventh heat exchange pipe 751 and an eighth heat exchange pipe 752 spaced apart from the seventh heat exchange pipe 751. The seventh heat exchange pipe 751 has a fifth liquid inlet and a fifth liquid outlet, both of which are connected to the fourth heat exchange pipe 73.

[0065] After heat exchange, the water enters the seventh heat exchange pipe 751 through the fifth inlet and is fed into the eighth heat exchange pipe 752, so that the cooling water in the eighth heat exchange pipe 752 exchanges heat with the water in the seventh heat exchange pipe 751 to cool down the water in the seventh heat exchange pipe 751. The water in the seventh heat exchange pipe 751 after heat exchange enters the fourth heat exchange pipe 73 through the fifth outlet to achieve circulation.

[0066] Combination Figure 2 In some embodiments, condensate is generated during the flue gas cooling process. The third heat exchanger 71 has a sixth liquid outlet 715, and the third liquid outlet 714 is located between the second air inlet 711 and the sixth liquid outlet 715. The second heat exchange assembly 70 also includes a condensate recovery pipe 76. The condensate recovery pipe 76 is connected to the sixth liquid outlet 715, and the condensate in the third heat exchanger 71 is discharged through the condensate recovery pipe 76.

[0067] In some embodiments, a level gauge is provided in the third heat exchanger 71, and a control valve is provided in the condensate recovery pipe 76. When the level value detected by the level gauge in the third heat exchanger 71 is greater than the set level value, the control valve is opened so that the condensate in the third heat exchanger 71 can be discharged through the condensate recovery pipe 76. When the level value detected by the level gauge in the third heat exchanger 71 is less than the set level value, the control valve is closed so that the condensate in the third heat exchanger 71 is no longer discharged through the condensate recovery pipe 76.

[0068] Combination Figure 2In some embodiments, in order to allow some of the flue gas inside the chimney 60 to enter the third heat exchanger 71, the second heat exchange assembly 70 further includes a second fan 78. The second fan 78 is located inside the second conveying pipe 72, and the fan 80 is activated to allow some of the flue gas inside the chimney 60 to enter the third heat exchanger 71 through the second conveying pipe 72.

[0069] In some embodiments, the inner wall of the third heat exchanger 71 is coated with a heavy-duty anti-corrosion coating, which can effectively prevent moisture and SO2 corrosion and extend the service life of the equipment.

[0070] In some embodiments, the heat recovery system adopts both remote and local modes. When operating at the machine site, the remote / local switch is switched to local mode. After the commissioning is completed, the remote / local switch is switched to remote mode, and the operator centrally operates the equipment from the control room.

[0071] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application.

[0072] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0073] In the description of this utility model, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0074] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0075] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0076] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A heat recovery system characterized by, The heat recovery system comprises: a first heat exchange assembly for recovering sensible heat of flue gas of an alumina calcination furnace; a flue gas pipeline in communication with the calcination furnace and the first heat exchange assembly; a first conveying pipeline in communication with the first heat exchange assembly; a bypass flue in communication with the flue gas pipeline and the first conveying pipeline; a regulating valve arranged in the bypass flue for adjusting the opening degree of the bypass flue; a chimney in communication with the first conveying pipeline; a second heat exchange assembly in communication with the chimney for recovering latent heat of flue gas after sensible heat recovery by the first heat exchange assembly.

2. The heat recovery system of claim 1, wherein, The first heat exchange assembly comprises: a first heat exchanger having a first gas inlet, a first gas outlet, a first liquid inlet and a first liquid outlet, the first gas inlet being in communication with the flue gas pipeline, and the first gas outlet being in communication with the first conveying pipeline; a first heat exchange pipeline in communication with the first liquid inlet and the first liquid outlet; at least one heat medium water circulating pump arranged in the first heat exchange pipeline; a second heat exchanger comprising a second heat exchange pipeline and a third heat exchange pipeline arranged at intervals with the second heat exchange pipeline, the second heat exchange pipeline having a second liquid inlet and a second liquid outlet, the second liquid inlet and the second liquid outlet being in communication with the first heat exchange pipeline; at least one pressurizing pump arranged in the third heat exchange pipeline.

3. The heat recovery system of claim 2, wherein, The first heat exchange assembly further comprises: a water supply tank; a water supply pipeline in communication with the water supply tank and the first heat exchange pipeline; a flow meter arranged in the first heat exchange pipeline for detecting the flow of liquid in the first heat exchange pipeline.

4. The heat recovery system of claim 2, wherein, The first heat exchange assembly further comprises: a first temperature detector arranged in the first heat exchange pipeline and located at the first liquid outlet; wherein if the first temperature value detected by the first temperature detector is less than a first set temperature value, the operating power of the heat medium water circulating pump is reduced, and if the first temperature value detected by the first temperature detector is greater than the first set temperature value, the operating power of the heat medium water circulating pump is increased.

5. The heat recovery system according to any one of claims 1 to 4, characterized in that, The heat recovery system further comprises: a first fan arranged in the first conveying pipeline.

6. The heat recovery system of claim 5, wherein, A dust collector is arranged between the calcination furnace and the first heat exchange assembly, the dust collector has a zero pressure point, and the heat recovery system further comprises: a pressure detector for detecting the pressure of the zero pressure point; wherein if the pressure of the zero pressure point detected by the pressure detector is positive, the operating frequency of the fan is increased, and if the pressure of the zero pressure point detected by the pressure detector is negative, the operating frequency of the fan is reduced.

7. The heat recovery system according to any one of claims 1 to 4, wherein The second heat exchange assembly comprises: a third heat exchanger having a second gas inlet, a second gas outlet, a third liquid inlet and a third liquid outlet, the third liquid inlet being located between the second gas inlet and the second gas outlet, and the second gas inlet being located between the third liquid inlet and the third liquid outlet; a second conveying pipeline in communication with the chimney and the second gas inlet; a fourth heat exchange pipeline in communication with the third liquid inlet and the third liquid outlet; The fourth heat exchanger comprises a fifth heat exchange pipeline and a sixth heat exchange pipeline which is spaced from the fifth heat exchange pipeline, the fifth heat exchange pipeline has a fourth liquid inlet and a fourth liquid outlet, and the fourth liquid inlet and the fourth liquid outlet are both communicated with the fourth heat exchange pipeline.

8. The heat recovery system of claim 7, wherein, The second heat exchange assembly comprises: The fifth heat exchanger is located between the fourth heat exchanger and the third liquid inlet, the fifth heat exchanger comprises a seventh heat exchange pipeline and an eighth heat exchange pipeline which is spaced from the seventh heat exchange pipeline, the seventh heat exchange pipeline has a fifth liquid inlet and a fifth liquid outlet, and the fifth liquid inlet and the fifth liquid outlet are both communicated with the fourth heat exchange pipeline.

9. The heat recovery system of claim 7, wherein, The third heat exchanger has a sixth liquid outlet, the third liquid outlet is located between the second gas inlet and the sixth liquid outlet, and the second heat exchange assembly further comprises: A condensate water recovery pipeline is communicated with the sixth liquid outlet.

10. The heat recovery system of claim 7, wherein, The second heat exchange assembly further comprises: A second fan is arranged in the second conveying pipeline.

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