Waste heat recovery device

Abstract

The utility model relates to the technical field of waste heat recovery, and discloses a waste heat recovery device, which is used for recovering waste heat of a plurality of fuel cell systems and comprises a heat exchanger, a plurality of heat exchange tubes and a plurality of heat exchange tubes, the gas inlet pipeline comprises a gas inlet main pipe and a plurality of gas inlet branch pipes, first valves are mounted on the gas inlet branch pipes, inlets of the plurality of gas inlet branch pipes are communicated with the plurality of fuel cell systems in a one-to-one correspondence manner, outlets of the plurality of gas inlet branch pipes are respectively communicated with an inlet of the gas inlet main pipe, and the gas inlet main pipe is communicated with the gas inlet branch pipes; an outlet of the air inlet header pipe is communicated with an air inlet of the heat exchanger; the first water tank is provided with a first water inlet, a first water outlet, a second water inlet and a second water outlet, the first water outlet is communicated with the liquid inlet of the heat exchanger through a water outlet pipe, and the first water inlet is communicated with the liquid outlet of the heat exchanger through a water inlet pipe. According to the waste heat recovery device, the heat recovery efficiency is improved, and the equipment cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a waste heat recovery technical field, especially a waste heat recovery device. BACKGROUND

[0002] Solid oxide fuel cells are widely used in power plants, data centers, hospitals and residences and other fields due to their high current density and high power density. The solid oxide fuel cell has a high working temperature, usually in the range of 800-1000℃, so it can utilize its waste heat to realize combined heat and power generation while generating electricity. In practical applications, multiple fuel cell systems are usually connected in parallel to output electric energy, thereby meeting the megawatt-level power demand. In the current parallel system scheme, each fuel cell system is provided with a corresponding waste heat recovery device to realize combined heat and power generation. However, this scheme has the following problems: on the one hand, multiple waste heat recovery devices need to be installed, which increases the equipment cost; on the other hand, the decentralized waste heat recovery mode increases the heat dissipation and reduces the energy utilization efficiency of the fuel cell system. SUMMARY

[0003] The utility model discloses a waste heat recovery device, which improves the heat recovery efficiency and reduces the equipment cost.

[0004] To achieve the above-mentioned purpose, the utility model provides a waste heat recovery device for recovering the waste heat of multiple fuel cell systems, comprising:

[0005] The heat exchanger has a gas inlet, a gas outlet, a liquid inlet and a liquid outlet.

[0006] The gas inlet pipeline comprises a gas inlet main pipe and multiple gas inlet branch pipes, the first valve is installed on the gas inlet branch pipe, the inlet of the multiple gas inlet branch pipes is communicated with the multiple fuel cell systems one by one, the outlet of the multiple gas inlet branch pipes is communicated with the inlet of the gas inlet main pipe respectively, and the outlet of the gas inlet main pipe is communicated with the gas inlet of the heat exchanger; and

[0007] The first water tank has a first water inlet, a first water outlet, a second water inlet and a second water outlet, the first water outlet is communicated with the liquid inlet of the heat exchanger through a water outlet pipe, and the first water inlet is communicated with the liquid outlet of the heat exchanger through a water inlet pipe.

[0008] In some embodiments, the gas inlet pipeline comprises multiple exhaust branch pipes, the multiple exhaust branch pipes are communicated with the gas inlet branch pipes one by one, the inlet of the exhaust branch pipe is installed on the gas inlet branch pipe between the first valve and the fuel cell system, and the second valve is installed on the exhaust branch pipe.

[0009] In some embodiments, the air inlet pipeline comprises a second temperature detection unit and a plurality of first temperature detection units, the plurality of first temperature detection units are installed on the plurality of air inlet branch pipes one by one, and the second temperature detection unit is installed on the air inlet main pipe.

[0010] In some embodiments, an air induction fan is included, which is in communication with the air outlet of the heat exchanger.

[0011] In some embodiments, a water amount control unit is included, which is installed on the water outlet pipe.

[0012] In some embodiments, the water amount control unit comprises a third valve, a first water pump and a flow meter, which are all installed on the water outlet pipe.

[0013] In some embodiments, a fourth valve, a fifth valve and a descaling loop are included, the fourth valve is installed on the water outlet pipe between the water amount control unit and the first water outlet, the fifth valve is installed on the water inlet pipe, the inlet of the descaling loop is in communication with the water inlet pipe between the fifth valve and the liquid outlet of the heat exchanger, and the outlet of the descaling loop is in communication with the water outlet pipe between the water amount control unit and the fourth valve.

[0014] In some embodiments, the descaling loop comprises a filter, a second water tank, a sixth valve, a seventh valve, a second water pump and a first blowdown valve, the first inlet of the second water tank is in communication with the water inlet pipe between the fifth valve and the liquid outlet of the heat exchanger through the second water pump and the seventh valve, the filter is used for inputting filtered tap water to the second inlet of the second water tank, the first outlet of the second water tank is in communication with the water outlet pipe between the water amount control unit and the fourth valve through the sixth valve, and the second outlet of the second water tank is in communication with the first blowdown valve.

[0015] In some embodiments, a second blowdown valve is included, the first water tank is in communication with the first inlet of the second water tank through the second blowdown valve and the second water pump.

[0016] In some embodiments, an eighth valve is included, which is installed on the water outlet pipe and located between the water amount control unit and the fourth valve.

[0017] The waste heat recovery device has the advantages that compared with the prior art, the waste heat recovery device has the advantages that

[0018] By communicating the inlets of the plurality of gas inlet branch pipes with the plurality of fuel cell systems one by one, respectively communicating the outlets of the plurality of gas inlet branch pipes with the inlets of the gas inlet main pipe, and communicating the outlet of the gas inlet main pipe with the gas inlet of the heat exchanger, and since the first water tank has a first water inlet, a first water outlet, a second water inlet and a second water outlet, the first water outlet is communicated with the liquid inlet of the heat exchanger through a water outlet pipe, and the first water inlet is communicated with the liquid outlet of the heat exchanger through a water inlet pipe, based on this, the tail gas of the fuel cell system and water are exchanged through the heat exchanger, the waste heat of the fuel cell system is recovered, the hot water generated by heat exchange and temperature rise is output from the liquid outlet of the heat exchanger, flows back to the first water tank through the first water inlet, and is discharged from the second water outlet for use by the user. The plurality of fuel cell systems are connected in parallel, and high-power output of electric energy can be realized. The tail gas discharged by the plurality of fuel cell systems connected in parallel is combined and input into the same waste heat recovery device, which can not only reduce equipment investment and cost, but also reduce heat energy dissipation and maintain a high energy utilization efficiency of the system. In addition, each first valve can control the communication of each fuel cell system with the heat exchanger, so as to flexibly control the emission of each fuel cell system. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A principle structure schematic view of the waste heat recovery device provided by the embodiment of the present application is shown.

[0020] Figure 2 A principle structure schematic view of the heat exchanger of the waste heat recovery device provided by the embodiment of the present application is shown.

[0021] Figure 3 A principle structure schematic view of the first water tank of the waste heat recovery device provided by the embodiment of the present application is shown.

[0022] Figure 4 A principle structure schematic view of the second water tank of the waste heat recovery device provided by the embodiment of the present application is shown.

[0023] In the figure: 1, heat exchanger; 11, air inlet; 12, air outlet; 13, liquid inlet; 14, liquid outlet; 2, air inlet pipeline; 21, air inlet main pipe; 22, air inlet branch pipe; 23, first valve; 24, air outlet branch pipe; 25, second valve; 26, first temperature detection unit; 27, second temperature detection unit; 3, first water tank; 31, first water inlet; 32, first water outlet; 33, second water inlet; 34, second water outlet; 35, water outlet pipe; 36, water inlet pipe; 37, second blowdown valve; 38, eighth valve; 5, induced draft fan; 6, water quantity control unit; 61, third valve; 62, first water pump; 63, flow meter; 7, fourth valve; 8, fifth valve; 9, descaling loop; 91, filter; 92, second water tank; 921, first inlet; 922, second inlet; 923, first outlet; 924, second outlet; 93, sixth valve; 94, seventh valve; 95, second water pump; 96, first blowdown valve. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application.

[0025] It should be understood that, in the description of the present application, the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated must be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features, that is, the features with "first", "second" can explicitly or implicitly include one or more of the features. In addition, unless otherwise stated, the meaning of "multiple" is two or more.

[0026] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict between them.

[0027] As Figures 1-4 shown, the waste heat recovery device 100 of the embodiment of the present application is used for recovering waste heat of multiple fuel cell systems 200, and comprises a heat exchanger 1, an air inlet pipeline 2 and a first water tank 3. The heat exchanger 1 can exchange heat between the tail gas heat of the multiple fuel cell systems 200 and water to generate hot water for use by a user.

[0028] The heat exchanger 1 has an air inlet 11, an air outlet 12, a liquid inlet 13 and a liquid outlet 14. The air inlet pipeline 2 comprises an air inlet main pipe 21 and a plurality of air inlet branch pipes 22, the first valve 23 is arranged on the air inlet branch pipe 22, the inlet of the air inlet branch pipe 22 is communicated with the fuel cell system 200 one by one, the outlet of the air inlet branch pipe 22 is communicated with the inlet of the air inlet main pipe 21 respectively, the outlet of the air inlet main pipe 21 is communicated with the air inlet 11 of the heat exchanger 1; the first water tank 3 has a first water inlet 31, a first water outlet 32, a second water inlet 33 and a second water outlet 34, the first water outlet 32 is communicated with the liquid inlet 13 of the heat exchanger 1 through the water outlet pipe 35, and the first water inlet 31 is communicated with the liquid outlet 14 of the heat exchanger 1 through the water inlet pipe 36.

[0029] In work, each fuel cell system 200 has a corresponding air inlet branch pipe 22 to discharge exhaust gas, each air inlet branch pipe 22 is connected with the air inlet main pipe 21, the diameter of the air inlet main pipe 21 is larger than that of the air inlet branch pipe 22, which is suitable for multiple fuel cell systems 200 to discharge exhaust gas at the same time, avoiding the damage of structural parts caused by excessive gas pressure. The outlet of the air inlet main pipe 21 is communicated with the air inlet 11 of the heat exchanger 1, and the heat exchanger 1 is used to convert the waste heat of the exhaust gas output by the air inlet main pipe 21 into usable heat through heat exchange, so as to improve the energy utilization rate. The first valve 23 is arranged on the air inlet branch pipe 22 instead of the air inlet main pipe 21, so as to flexibly control the exhaust condition of each fuel cell system 200.

[0030] Based on the above structure, the inlet of the plurality of air inlet branch pipes 22 is communicated with the fuel cell system 200 one by one, the outlet of the plurality of air inlet branch pipes 22 is communicated with the inlet of the air inlet main pipe 21 respectively, the outlet of the air inlet main pipe 21 is communicated with the air inlet 11 of the heat exchanger 1; the first water tank 3 has a first water inlet 31, a first water outlet 32, a second water inlet 33 and a second water outlet 34, the first water outlet 32 is communicated with the liquid inlet 13 of the heat exchanger 1 through the water outlet pipe 35, and the first water inlet 31 is communicated with the liquid outlet 14 of the heat exchanger 1 through the water inlet pipe 36. In this way, the exhaust gas of the fuel cell system 200 and the water are exchanged through the heat exchanger 1, the waste heat of the fuel cell system 200 is recovered, the hot water generated by heat exchange and temperature rise is output from the liquid outlet of the heat exchanger 1, flows back to the first water tank 3 through the first water inlet 31, and is discharged from the second water outlet 34 for user use. The plurality of fuel cell systems 200 are connected in parallel, which can realize high-power output of electric energy. The exhaust gas discharged by the plurality of fuel cell systems 200 connected in parallel is combined and input into the same waste heat recovery device 100, which can not only reduce equipment investment and cost, but also reduce heat dissipation and maintain high energy utilization efficiency of the system. In addition, each first valve 23 can control the communication between each fuel cell system 200 and the heat exchanger 1, so as to flexibly control the exhaust condition of each fuel cell system 200.

[0031] AsFigure 1 As shown, in some embodiments, the intake pipe 2 includes multiple exhaust branch pipes 24, which are connected one-to-one with the intake branch pipe 22. The inlet of each exhaust branch pipe 24 is installed on the intake branch pipe 22 between the first valve 23 and the fuel cell system 200. A second valve 25 is installed on each exhaust branch pipe 24. The exhaust branch pipe 24 is used to directly discharge the exhaust gas from the intake branch pipe 22. Specifically, when the heat exchanger 1 malfunctions, all the first valves 23 can be closed and all the second valves 25 can be opened to allow the exhaust gas to be discharged from the exhaust branch pipe 24, preventing excessive gas pressure from damaging the system. If one of the fuel cell systems 200 malfunctions, its corresponding first valve 23 can be closed, allowing the gas flow to be discharged through the second valve 25, preventing excessive gas pressure from damaging the system. For ease of use, the second valve 25 is an automatic exhaust valve.

[0032] like Figure 1 As shown, in some embodiments, the intake pipe 2 includes a second temperature detection unit 27 and multiple first temperature detection units 26. The multiple first temperature detection units 26 are installed one-to-one on multiple intake branch pipes 22, and the second temperature detection unit 27 is installed on the intake manifold 21. It should be noted that since the temperature of the exhaust gas output from the intake branch pipe 22 is related to the operating state of the fuel cell system 200 and the source of the internal exhaust gas, if the exhaust gas temperature in the intake branch pipe 22 is lower than the exhaust gas temperature in the intake manifold 21, the resulting temperature difference will cause convective heat transfer of the gas, reducing energy utilization efficiency. Therefore, the first temperature detection unit 26 detects the exhaust gas temperature T1 in the intake branch pipe 22, and the second temperature detection unit 27 detects the exhaust gas temperature T2 in the intake manifold 21. When the exhaust gas temperature T1 in the intake branch pipe 22 is detected to be lower than the exhaust gas temperature T2 in the intake manifold 21, the first valve 23 is closed and the second valve 25 is opened, allowing the exhaust gas to be discharged from the exhaust branch pipe 24, preventing the exhaust gas from entering the intake manifold 21. The first valve 23 can be a manual valve, which is manually opened when T1 is greater than or equal to T2; or it can be an electrically controlled valve, which is automatically opened when T1 is greater than or equal to T2.

[0033] like Figure 1 As shown, in some embodiments, the waste heat recovery device 100 includes an induced draft fan 5, which is connected to the outlet 12 of the heat exchanger 1. Thus, to prevent the module casing in the fuel cell system 200 from deforming beyond design requirements or causing glass and other internal seals to fail after long-term operation, the pressure loss in the fuel cell system 200's piping is not allowed to exceed the design pressure limit. Compared to existing waste heat recovery devices, the total pressure loss in the inlet piping 2 of the waste heat recovery device 100 in this embodiment is greater. Therefore, an induced draft fan 5 is used to exhaust air at the outlet 12 of the heat exchanger 1 to reduce the module back pressure.

[0034] like Figure 1As shown, in some embodiments, the waste heat recovery device 100 includes a water flow control unit 6, which is installed on the outlet pipe 35. The water flow control unit 6 is used to control the water flow rate of the outlet pipe 35.

[0035] Specifically, in some embodiments, the water control unit 6 includes a third valve 61, a first water pump 62, and a flow meter 63, all of which are installed on the outlet pipe 35. The third valve 61 controls the input and output of water in the outlet pipe 35. The first water pump 62 pressurizes the liquid and delivers it through the outlet pipe 35 when the water pressure is insufficient. The flow meter 63 records the flow velocity and flow rate of the liquid in the outlet pipe 35. The positions of the flow meter 63 and the first water pump 62 are important. The first water pump 62 determines the water flow velocity, and the flow meter 63's measurement is related to the water flow velocity. Therefore, the flow meter 63 is positioned in front of the first water pump 62 to avoid fluctuations in the flow meter reading caused by the vibration of the first water pump 62, which would result in inaccurate readings. For example, if the water flow direction is from right to left, and the flow meter 63 is to the left of the first water pump 62, vibration of the first water pump 62 would cause fluctuations in the flow meter reading.

[0036] like Figure 1 and 4 As shown, in some embodiments, the waste heat recovery device 100 includes a fourth valve 7, a fifth valve 8, and a descaling loop 9. The fourth valve 7 is installed on the outlet pipe 35 between the water volume control unit 6 and the first outlet 32. The fifth valve 8 is installed on the inlet pipe 36. The inlet of the descaling loop 9 is connected to the inlet pipe 36 between the fifth valve 8 and the outlet 14 of the heat exchanger 1, and the outlet of the descaling loop 9 is connected to the outlet pipe 35 between the water volume control unit 6 and the fourth valve 7. During the operation of the heat exchanger 1, corrosion occurs on the heat exchange surface, producing scale or microbial sludge to form a scale layer. The scale layer has a low thermal conductivity and high thermal resistance, which greatly reduces the heat exchange efficiency. Therefore, in this embodiment, the heat exchanger 1 is connected to the descaling loop 9. Under normal operating conditions, the exhaust gas in the heat exchanger 1 exchanges heat with the cold water, and hot water is output to the first water tank 3 for storage. When heat exchanger 1 is not in use, close the fourth valve 7 and the fifth valve 8 to prevent the descaling solution from entering the first water tank 3, and descale heat exchanger 1 through the descaling loop 9 to achieve the descaling function.

[0037] Specifically, in some embodiments, the descaling loop 9 comprises a filter 91, a second water tank 92, a sixth valve 93, a seventh valve 94, a second water pump 95 and a first drain valve 96, a first inlet 921 of the second water tank 92 is communicated with the water inlet pipe 36 between the fifth valve 8 and the liquid outlet 14 of the heat exchanger 1 through the second water pump 95 and the seventh valve 94, the filter 91 is used to input filtered tap water to a second inlet 922 of the second water tank 92, a first outlet 923 of the second water tank 92 is communicated with the water outlet pipe 35 between the water quantity control unit 6 and the fourth valve 7 through the sixth valve 93, and a second outlet 924 of the second water tank 92 is communicated with the first drain valve 96. Thus, when the heat exchanger 1 is descaled, the third valve 61, the sixth valve 93 and the seventh valve 94 are in an open state, the fourth valve 7 and the fifth valve 8 are closed, and the sixth valve 93 and the seventh valve 94 are used to control the opening and closing of the descaling loop. When waste heat is recovered, the sixth valve 93 and the seventh valve 94 are in a closed state to prevent hot water from entering the second water tank 92. After the tap water is filtered by the filter 91, the filtered tap water enters the second water tank 92 through the second inlet 922, a descaling agent is dissolved in the water to form a descaling solution, and the descaling solution can be recycled. The descaling solution is discharged from the first outlet 923 of the second water tank 92, enters the liquid inlet 13 of the heat exchanger 1 after passing through the sixth valve 93, and flows out of the liquid outlet 14 of the heat exchanger 1 after the heat exchanger 1 is descaled, and then returns to the second water tank 92 through the seventh valve 94 and the second water pump 95. The above process is a cycle. In this embodiment, the descaling loop 9 can control the descaling cycle time of the descaling loop by controlling the opening time of each valve.

[0038] As shown in Figure 1 some embodiments, the waste heat recovery device 100 comprises a second drain valve 37, and the first water tank 3 is communicated with the first inlet 921 of the second water tank 92 through the second drain valve 37 and the second water pump 95. The second drain valve 37 is used to drain the dirt in the first water tank 3.

[0039] As shown in Figure 1 some embodiments, the waste heat recovery device 100 comprises an eighth valve 38, the eighth valve 38 is installed on the water outlet pipe 35 and located between the water quantity control unit 6 and the fourth valve 7, and in addition, the installation position of the eighth valve 38 is also located on the communication pipe between the water quantity control unit 6 and the sixth valve 93. Thus, when the first water tank 3 needs to be cleaned, the fifth valve 8 and the eighth valve 38 are closed, the fourth valve 7 and the second drain valve 37 of the first water tank 3 are opened, the descaling solution enters the first water tank 3 through the sixth valve 93 and the fourth valve 7; after the first water tank 3 is descaled, the descaling solution flows out of the second drain valve 37 of the first water tank 3, and then returns to the second water tank 92 through the second water pump 95, so as to realize the cleaning of the first water tank 3.

[0040] The above merely is the preferred implementation form of the present application, and it should be noted that, for the ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and substitutions can be made, and these improvements and substitutions should also be considered as the protection scope of the present application.

Claims

1. A heat recovery device, characterized by, A waste heat recovery system for a plurality of fuel cell systems, comprising: a heat exchanger having an air inlet, an air outlet, a liquid inlet, and a liquid outlet; an air inlet pipeline including an air inlet main pipe and a plurality of air inlet branch pipes, the air inlet branch pipes being provided with first valves, the air inlet branch pipes being in one-to-one correspondence with the plurality of fuel cell systems, the air inlet branch pipes being in communication with the air inlet main pipe, and the air inlet main pipe being in communication with the air inlet of the heat exchanger; and a first water tank having a first water inlet, a first water outlet, a second water inlet, and a second water outlet, the first water outlet being in communication with the liquid inlet of the heat exchanger via a water outlet pipe, and the first water inlet being in communication with the liquid outlet of the heat exchanger via a water inlet pipe.

2. The heat recovery device according to claim 1, characterized by The air inlet pipeline includes a plurality of exhaust branch pipes, the exhaust branch pipes being in one-to-one correspondence with the air inlet branch pipes, and the exhaust branch pipes being provided with second valves.

3. The heat recovery device according to claim 2, characterized in that, The air inlet pipeline includes a second temperature detection unit and a plurality of first temperature detection units, the first temperature detection units being provided on the air inlet branch pipes in one-to-one correspondence, and the second temperature detection unit being provided on the air inlet main pipe.

4. The heat recovery device according to claim 1, wherein The system includes an air blower, the air blower being in communication with the air outlet of the heat exchanger.

5. The heat recovery device according to claim 1, wherein The system includes a water amount control unit, the water amount control unit being provided on the water outlet pipe.

6. The heat recovery device according to claim 5, wherein The water amount control unit includes a third valve, a first water pump, and a flow meter, the third valve, the first water pump, and the flow meter being provided on the water outlet pipe.

7. The heat recovery device according to claim 5, wherein The system includes a fourth valve, a fifth valve, and a descaling loop, the fourth valve being provided on the water outlet pipe between the water amount control unit and the first water outlet, the fifth valve being provided on the water inlet pipe, the descaling loop being in communication with the water inlet pipe between the fifth valve and the liquid outlet of the heat exchanger, and the descaling loop being in communication with the water outlet pipe between the water amount control unit and the fourth valve.

8. The heat recovery device according to claim 7, wherein The descaling loop includes a filter, a second water tank, a sixth valve, a seventh valve, a second water pump, and a first blowdown valve, the first inlet of the second water tank being in communication with the water inlet pipe between the fifth valve and the liquid outlet of the heat exchanger via the second water pump and the seventh valve, the filter being configured to input filtered tap water to the second inlet of the second water tank, the first outlet of the second water tank being in communication with the water outlet pipe between the water amount control unit and the fourth valve via the sixth valve, and the second outlet of the second water tank being in communication with the first blowdown valve.

9. The heat recovery device according to claim 8, characterized in that The system includes a second blowdown valve, the first water tank being in communication with the second water tank via the second blowdown valve and the second water pump.

10. The heat recovery device according to claim 9, wherein The system includes an eighth valve, the eighth valve being provided on the water outlet pipe and being located between the water amount control unit and the fourth valve.

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