Flue gas driven heat pump waste heat deep recovery system

Abstract

The utility model discloses a flue gas-driven heat pump waste heat deep recovery system, relates to the technical field of flue gas waste heat recovery, and aims to solve the problem that a coal-fired hot water boiler cannot absorb desulfurized flue gas waste heat by using a heat pump. The flue gas-driven heat pump waste heat deep recovery system comprises a boiler, and the boiler is communicated with a generator of a heat pump through a smoke pipe I; the generator is communicated with the desulfurization tower through a smoke pipe II, and the desulfurization tower is communicated with the waste heat recovery tower through a smoke pipe III; a liquid outlet and a liquid return opening of the desulfurizing tower are communicated with the heat exchanger through a solution water supply pipe and a solution water return pipe respectively; a liquid outlet and a liquid return port of the waste heat recovery tower are respectively communicated with a medium water supply pipe and a medium water return pipe, the medium water supply pipe is also communicated with the heat exchanger, the heat exchanger is communicated with an evaporator of the heat pump through a transfer pipe corresponding to the output end of the medium water supply pipe, and the medium water return pipe is also communicated with the evaporator; and the heat supply network backwater and the boiler are respectively communicated with an absorber and a condenser of the heat pump.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas waste heat recovery, and in particular to a flue gas driven heat pump deep waste heat recovery system. Background Art

[0002] The flue gas generated by the coal-fired hot water boiler passes through the desulfurization tower and is discharged into the chimney. The final exhaust temperature is around 60°C. The flue gas contains a large amount of latent heat, which accounts for about 7% of the low calorific value of the fuel. Direct discharge not only brings about energy waste, but also causes "white smoke" to come out of the chimney due to the high humidity.

[0003] The return water from the primary heating network is directly heated by boilers. During the coldest seasons, the return water temperature is generally around 50°C. After being heated by boilers, it is delivered to various heating stations. Because the temperature of the flue gas after desulfurization is comparable to the return water temperature, it cannot be used to directly heat the return water from the heating network.

[0004] In order to recover the waste heat in the flue gas after desulfurization, a heat pump unit is usually added to the boiler room to generate low-temperature cold water to recover the waste heat of the flue gas after desulfurization. Gas boilers usually use direct-fired heat pumps, and steam boilers use steam-driven absorption heat pumps. Coal-fired hot water boilers do not have the above two driving heat sources. Therefore, at present, coal-fired hot water boilers cannot use heat pumps to absorb the waste heat of the flue gas after desulfurization. Utility Model Content

[0005] In order to solve the above problem, that is, the problem that the coal-fired hot water boiler cannot use the heat pump to absorb the waste heat of the flue gas after desulfurization, the utility model proposes a flue gas driven heat pump deep waste heat recovery device, which includes a boiler, the smoke outlet of the boiler is connected to a smoke pipe 1, the output end of the smoke pipe 1 is connected to the generator of the heat pump; the smoke outlet of the generator is connected to a smoke pipe 2, the output end of the smoke pipe 2 is connected to a desulfurization tower, the smoke outlet of the desulfurization tower is connected to a smoke pipe 3, the output end of the smoke pipe 3 is connected to the waste heat recovery tower; the liquid outlet and the liquid return port of the desulfurization tower are respectively connected to a solution water supply pipe and a solution return pipe, and the solution water supply pipe is connected to the desulfurization tower. The pipe and the other end of the solution return pipe are connected with a heat exchanger; the liquid outlet and liquid return port of the waste heat recovery tower are respectively connected with the medium water supply pipe and the medium return pipe, and the medium water supply pipe is also connected with the heat exchanger, and the output end of the heat exchanger corresponding to the medium water supply pipe is connected with a transfer pipe, the other end of the transfer pipe is connected with the evaporator of the heat pump, and the other end of the medium return pipe is also connected with the evaporator to realize the circulation of the medium in the waste heat recovery tower; the heat network return water is connected with the absorber of the heat pump, the absorber is connected with the condenser of the heat pump, and the output end of the condenser is connected with the water supply port of the boiler.

[0006] The present invention is further configured as follows: a circulation pump is installed on both the solution water supply pipe and the medium water supply pipe.

[0007] The present invention is further configured as follows: a valve is connected between the smoke pipe 1 and the smoke pipe 2 through a bypass pipe; the valve is also connected between the solution water supply pipe and the solution return pipe through a bypass pipe; the valve is also connected between the medium water supply pipe and the transfer pipe through a bypass pipe; and the valve is also connected between the heat network return water and the boiler water supply port through a bypass pipe.

[0008] The utility model is further configured as follows: a dust collector is installed on the smoke pipe.

[0009] The beneficial effects of the utility model are:

[0010] 1. The desulfurization solvent in the desulfurization tower can absorb the heat in the flue gas while desulfurizing it, and the medium in the waste heat recovery tower can also absorb the heat of the flue gas in the waste heat recovery tower. The desulfurization solvent and the medium can exchange heat through the heat exchanger, thereby realizing the deep recovery of the flue gas waste heat, reducing the exhaust temperature to 20-30℃, and fully recovering the sensible heat and latent heat in the flue gas, greatly improving the waste heat recovery rate and reducing energy consumption.

[0011] 2. The desulfurization tower is indirectly connected to the heat pump through a heat exchanger, which can prevent the desulfurization solvent from directly contacting the internal structure of the heat pump and further improve the service life of the heat pump.

[0012] 3. The flue gas in the waste heat recovery tower can come into contact with the low-temperature medium, and the steam in the flue gas can condense when encountering the low-temperature medium, thereby achieving the purpose of dehydrating the flue gas and further achieving the purpose of de-whitening the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Shown is a structural schematic diagram of the present utility model.

[0014] Figure 2 The figure shows the flow direction of the smoke of the utility model.

[0015] Figure 3 The diagram shows the circulation flow direction of the desulfurization solvent and medium of the utility model.

[0016] Figure numerals: 1. Boiler; 11. Flue gas pipe 1; 111. Dust collector; 2. Heat pump; 21. Generator; 22. Evaporator; 23. Absorber; 24. Condenser; 3. Flue gas pipe 2; 4. Desulfurization tower; 41. Solution water supply pipe; 42. Solution return pipe; 5. Flue gas pipe 3; 6. Recovery tower; 61. Medium water supply pipe; 62. Medium return pipe; 7. Heat exchanger; 71. Transfer pipe; 8. Circulation pump; 9. Valve. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0018] refer to Figure 1 The utility model proposes a flue gas driven heat pump deep waste heat recovery device, including a boiler 1, the boiler 1 is a coal-fired hot water boiler 1, the smoke removal port of the boiler 1 is connected to a smoke pipe 11, the output end of the smoke pipe 11 is connected to an absorption heat pump 2, the absorption heat pump 2 is a prior art, which includes a generator 21, a condenser 24, an evaporator 22 and an absorber 23, and the four are connected and work according to the method of the existing absorption heat pump 2.

[0019] refer to Figure 2 The output end of the smoke pipe 11 is connected to the generator 21 so that the flue gas is used as a driving heat source for the generator 21. The smoke outlet of the generator 21 is connected to the smoke pipe 23, that is, the smoke pipe 23 is used to discharge the flue gas input into the generator 21 by the smoke pipe 11. The output end of the smoke pipe 23 is connected to the desulfurization tower 4. A smoke inlet is provided on the side wall of the desulfurization tower 4, and a smoke outlet is provided at the top of the desulfurization tower 4. A spray device is installed in the desulfurization tower 4. The spray device is arranged above the smoke inlet to spray a desulfurization solvent into the desulfurization tower 4, thereby achieving desulfurization of the flue gas.

[0020] The smoke outlet of the desulfurization tower 4 is connected to a smoke pipe 3 5, and the output end of the smoke pipe 3 5 is connected to a waste heat recovery tower 6. The waste heat recovery tower 6 includes a medium for heat conduction. The medium is water. The medium can absorb part of the heat of the flue gas in the waste heat recovery tower 6. When the flue gas comes into contact with the medium, the steam in the flue gas condenses when it is cooled, thereby achieving the purpose of removing water vapor in the flue gas and achieving the effect of de-whitening the flue gas.

[0021] A smoke inlet is provided on the side wall of the waste heat recovery tower 6, the output end of the smoke pipe three 5 is connected to the smoke inlet of the waste heat recovery tower 6, the top of the waste heat recovery tower 6 is a smoke outlet, and a spray device is also installed in the waste heat recovery tower 6 for spraying the medium into the waste heat recovery tower 6.

[0022] refer to Figure 3 The desulfurization tower 4 is also provided with a liquid outlet and a liquid return port, wherein the liquid return port is connected to the spraying device. The liquid outlet is connected to a solution water supply pipe 41, and the liquid return port is connected to a solution return pipe 42. The ends of the solution supply pipe 41 and the solution return pipe 42 facing away from the desulfurization tower 4 are connected to a heat exchanger 7. The corresponding input and output ends of one side of the heat exchanger 7 are connected to the solution water supply pipe 41 and the solution return pipe 42, respectively, to realize the circulation of the desulfurization solvent between the desulfurization tower 4 and the heat exchanger 7.

[0023] The waste heat recovery tower 6 is also provided with a liquid outlet and a liquid return port, wherein the liquid return port is also connected to the spray device, the liquid outlet is connected to a medium water supply pipe 61, and the liquid return port is connected to a medium return pipe 62. The medium water supply pipe 61 is connected to the input end on the other side of the heat exchanger 7, and the output end of the corresponding medium water supply pipe 61 on the heat exchanger 7 is connected to a transfer pipe 71, and the other end of the transfer pipe 71 is connected to the input end of the refrigerant water of the evaporator 22, so that the medium serves as the refrigerant water of the evaporator 22, and the medium return pipe 62 is connected to the output end of the refrigerant water of the evaporator 22, so that the medium can circulate between the waste heat recovery tower 6, the heat exchanger 7 and the evaporator 22.

[0024] The cooling water input end of the absorber 23 is connected to the return water of the heat network, the cooling water output end of the absorber 23 is connected to the cooling water input end of the condenser 24, and the cooling water output end of the condenser 24 is connected to the water supply port of the boiler 1, thereby realizing the circulation of the heat network water. At the same time, the return water of the heat network can also be used as cooling water for the absorber 23 and the condenser 24.

[0025] Circulation pumps 8 are installed on both the solution water supply pipe 41 and the medium water supply pipe 61 to meet the circulation work of the desulfurization solvent and the medium.

[0026] A valve 9 is connected between the smoke pipe 11 and the smoke pipe 2 3 through a bypass pipe; a valve 9 is also connected between the solution water supply pipe 41 and the solution return water pipe 42 through a bypass pipe; a valve 9 is also connected between the medium water supply pipe 61 and the transfer pipe 71 through a bypass pipe, and a valve 9 is also connected between the heat network return water and the water supply port of the boiler 1 through a bypass pipe. The valve 9 is a normally closed stop valve, that is, when a fault occurs in the corresponding part, the valve 9 is opened to facilitate maintenance.

[0027] A dust collector 111 is also installed on the smoke pipe 11, and the dust collector 111 is used to remove dust from the smoke.

[0028] It should be noted that the heat pump 2 uses lithium bromide solvent as the absorbent, and a spiral finned tube is provided in the shell of the generator 21. The lithium bromide solvent is placed in the spiral finned tube. The flue gas flows on the outside of the spiral finned tube and heats the spiral finned tube through the flue gas.

[0029] In summary, the desulfurization solvent in the desulfurization tower 4 of the present invention can absorb the heat in the flue gas while desulfurizing the flue gas, and the medium in the waste heat recovery tower 6 can also absorb the heat of the flue gas in the waste heat recovery tower 6. The desulfurization solvent and the medium can exchange heat through the heat exchanger 7, thereby achieving deep recovery of the flue gas waste heat, reducing the exhaust temperature to 20-30°C, and fully recycling the sensible heat and latent heat in the flue gas, greatly improving the waste heat recovery rate and reducing energy consumption. The desulfurization tower 4 is indirectly connected to the heat pump 2 through the heat exchanger 7, which can prevent the desulfurization solvent from directly contacting the internal structure of the heat pump 2, further improving the service life of the heat pump 2. The flue gas in the waste heat recovery tower 6 can come into contact with the low-temperature medium, and the steam in the flue gas can condense when encountering the low-temperature medium, thereby achieving the purpose of dehydrating the flue gas, and then achieving the purpose of dewhitening the flue gas.

[0030] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

[0031] In the description of this utility model, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are merely for ease of description and are not intended to indicate or imply that the device or component described must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] Furthermore, it should be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0033] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed or inherent to such process, article, or apparatus / device.

[0034] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A flue gas driven heat pump deep waste heat recovery system, comprising a boiler (1), wherein the flue gas outlet of the boiler (1) is connected to a flue pipe (11), characterized in that: The output end of the smoke pipe 1 (11) is connected to the generator (21) of the heat pump (2); the smoke outlet of the generator (21) is connected to the smoke pipe 2 (3), the output end of the smoke pipe 2 (3) is connected to the desulfurization tower (4), the smoke outlet of the desulfurization tower (4) is connected to the smoke pipe 3 (5), and the output end of the smoke pipe 3 (5) is connected to the waste heat recovery tower (6); the liquid outlet and the liquid return port of the desulfurization tower (4) are respectively connected to the solution water supply pipe (41) and the solution water return pipe (42), and the other ends of the solution water supply pipe (41) and the solution water return pipe (42) are connected to the heat exchanger (7); the liquid outlet and the liquid return port of the waste heat recovery tower (6) are respectively connected to the medium water supply pipe (61 ) and a medium return pipe (62), the medium water supply pipe (61) is also connected to the heat exchanger (7), the heat exchanger (7) is connected to a transfer pipe (71) corresponding to the output end of the medium water supply pipe (61), the other end of the transfer pipe (71) is connected to the evaporator (22) of the heat pump (2), and the other end of the medium return pipe (62) is also connected to the evaporator (22) to realize the circulation of the medium in the waste heat recovery tower (6); the heat network return water is connected to the absorber (23) of the heat pump (2), the absorber (23) is connected to the condenser (24) of the heat pump (2), and the output end of the condenser (24) is connected to the water supply port of the boiler (1).

2. The flue gas driven heat pump deep waste heat recovery system according to claim 1 is characterized by: A circulation pump (8) is installed on both the solution water supply pipe (41) and the medium water supply pipe (61).

3. The flue gas driven heat pump deep waste heat recovery system according to claim 1 is characterized by: The smoke pipe 1 (11) and the smoke pipe 2 (3) are connected to each other via a bypass pipe with a valve (9); the solution water supply pipe (41) and the solution return water pipe (42) are also connected to each other via a bypass pipe with the valve (9); the medium water supply pipe (61) and the transfer pipe (71) are also connected to each other via a bypass pipe with the valve (9); the heat network return water and the water supply port of the boiler (1) are also connected to each other via a bypass pipe with the valve (9).

4. The flue gas driven heat pump deep waste heat recovery system according to claim 1 is characterized by: A dust collector (111) is installed on the smoke pipe (11).

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