Flue gas waste heat recovery device of coal-fired boiler

Abstract

The utility model provides a flue gas waste heat recovery device of a coal-fired boiler. The flue gas waste heat recovery device comprises the coal-fired boiler, an economizer, a spray tower, an absorption heat pump and a valve. Flue gas of the coal-fired boiler is discharged after being cooled through the economizer and the spray tower in sequence. High-temperature flue gas in the economizer exchanges heat with water, generated high-temperature hot water serves as a driving heat source of the absorption heat pump and enters the absorption heat pump generator, and the absorption heat pump is driven by the high-temperature water to recover low-temperature flue gas waste heat from the spraying tower and heat return water of a heat supply network. Heat supply network return water sequentially enters the absorption heat pump absorber and the condenser to be heated, then part of the heat supply network return water enters the economizer to be heated, the other part of the heat supply network return water passes through the valve to be mixed with water heated through the economizer, and then the heat supply network return water enters the boiler to be heated to be provided for heat users. Heat of high-temperature flue gas is used as a heat pump driving heat source, gradient utilization of boiler flue gas is achieved, and the overall utilization efficiency of energy is improved.

Description

Technical Field

[0001] The utility model belongs to the field of waste heat recovery, and particularly relates to a coal-fired boiler flue gas waste heat recovery device. Background Art

[0002] Coal-fired boiler exhaust contains a lot of waste heat, and direct emission leads to energy waste. In order to recover the waste heat of flue gas, absorption heat pumps have been more and more widely used. By consuming a certain amount of driving heat source, absorption heat pumps can recover the low-temperature waste heat in the flue gas and provide it to heat users.

[0003] Absorption heat pumps have high requirements for the temperature grade of the driving heat source. The outlet water temperature of traditional coal-fired hot water boilers cannot meet its requirements. Therefore, in order to recover the waste heat of coal-fired boiler flue gas, it is often necessary to adjust the operating conditions of the boiler, such as increasing the boiler inlet water temperature or reducing the boiler inlet water flow, thereby increasing the boiler outlet water temperature to meet the temperature requirements of the absorption heat pump driving heat source. However, if the boiler outlet water temperature is increased, it will not be able to match the temperature requirements of the original heat users. Therefore, after meeting the temperature requirements of the heat pump driving heat source, it is necessary to use bypass water mixing to reduce the temperature of the boiler's external water supply. This not only causes the boiler itself to deviate from the rated operating conditions, but also causes additional losses due to water mixing, reducing the overall energy utilization efficiency.

[0004] It can be seen that it is of great significance to propose a coal-fired boiler flue gas waste heat recovery device that does not need to increase the boiler outlet water temperature and can achieve the heat pump unit's driving heat source temperature requirement. Summary of the invention

[0005] (I) Purpose of the invention

[0006] The purpose of the utility model is to provide a coal-fired boiler flue gas waste heat recovery device, which utilizes the economizer in the original boiler system, reduces the heat exchange temperature difference of the economizer through valve adjustment, increases the outlet water temperature of the economizer, and serves as a driving heat source for an absorption heat pump, thereby avoiding the waste of high-temperature flue gas. At the same time, the absorption heat pump is used to recover the low-temperature waste heat of the flue gas, thereby improving the overall energy utilization efficiency.

[0007] (II) Technical solution

[0008] In order to solve the above problems, the utility model provides a coal-fired boiler flue gas waste heat recovery device, comprising:

[0009] Coal-fired boilers, economizers, spray towers, absorption heat pumps, valves.

[0010] The absorption heat pump includes a generator, a condenser, an evaporator and an absorber.

[0011] The flue gas outlet of the coal-fired boiler is connected to the flue gas inlet of the economizer, and the flue gas outlet of the economizer is connected to the flue gas inlet of the spray tower;

[0012] The return water of the heating network is connected to the inlet of the absorption heat pump absorber, the outlet of the absorption heat pump absorber is connected to the inlet of the absorption heat pump condenser, the outlet of the absorption heat pump condenser is connected to the inlet of the valve, the outlet of the valve is connected to the hot water inlet of the coal-fired boiler, and the hot water outlet of the coal-fired boiler is connected to the water supply of the heating network;

[0013] The return water of the heat network is connected to the water side inlet of the economizer, and the water side outlet of the economizer is connected to the hot water inlet of the coal-fired boiler;

[0014] The water side outlet of the economizer is connected to the heat source inlet of the absorption heat pump generator, and the heat source outlet of the absorption heat pump generator is connected to the water side inlet of the economizer;

[0015] The outlet of the absorption heat pump evaporator is connected to the inlet of the spray tower, and the outlet of the spray tower is connected to the inlet of the absorption heat pump evaporator.

[0016] Furthermore, the water side outlet of the economizer is connected to the water supply of the heating network.

[0017] Furthermore, the outlet of the absorption heat pump condenser is connected to the water supply of the heating network.

[0018] Furthermore, it also includes a flue gas heat exchanger, the flue gas outlet of the economizer is connected to the flue gas inlet of the flue gas heat exchanger, the flue gas outlet of the flue gas heat exchanger is connected to the flue gas inlet of the spray tower, the water side outlet of the flue gas heat exchanger is connected to the heat source inlet of the absorption heat pump generator, and the heat source outlet of the absorption heat pump generator is connected to the water side inlet of the flue gas heat exchanger.

[0019] (III) Beneficial effects

[0020] The above technical solution of the utility model has the following beneficial technical effects:

[0021] The utility model device utilizes high-temperature flue gas to heat and generate hot water by adding absorption heat pumps, water valves and other equipment as the driving heat source of the absorption heat pump, recovers the low-temperature waste heat of the flue gas through the absorption heat pump, and provides it to heat users. By utilizing the flue gas of coal-fired boilers in a cascade manner, the waste of high-temperature flue gas is avoided, and the overall energy utilization efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the device structure of Example 1 of the utility model;

[0023] Figure 2 It is a schematic diagram of the device structure of Example 2 of the utility model;

[0024] Figure 3It is a schematic diagram of the device structure of Example 3 of the utility model;

[0025] Figure 4 This is a schematic diagram of the device structure of Example 4 of the utility model

[0026] Reference numerals:

[0027] 1: coal-fired boiler; 101: coal-fired boiler flue gas outlet; 102: coal-fired boiler hot water inlet; 103: coal-fired boiler hot water outlet; 2: economizer; 201: economizer flue gas inlet; 202: economizer flue gas outlet; 203: economizer water side inlet; 204: economizer water side outlet; 3: spray tower; 301: spray tower flue gas inlet; 302: spray tower flue gas outlet; 303: spray tower inlet; 304: spray tower outlet; 4: absorption heat pump; G: generator; G01: heat source inlet; G02: heat source outlet; E: evaporator; E01: evaporator inlet; E02: evaporator outlet; A: absorber; A01: absorber inlet; A02: absorber outlet; C: condenser; C01: condenser inlet; C02: condenser outlet; 5: valve; 501: valve inlet; 502: valve outlet; 6: flue gas heat exchanger; 601: flue gas inlet of flue gas heat exchanger; 602: flue gas outlet of flue gas heat exchanger; 603: water side inlet of flue gas heat exchanger; 604: water side outlet of flue gas heat exchanger. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail below in combination with specific implementation methods and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the utility model. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.

[0029] The terms "including" and "having" and any variations thereof in the specification and claims of the present utility model and the above drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0030] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] Obviously, the described embodiments are part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model. In addition, the technical features involved in the different embodiments of the utility model described below can be combined with each other as long as they do not conflict with each other. The utility model will be described in more detail below with reference to the accompanying drawings. In each of the drawings, the same elements are represented by similar figure numerals. For the sake of clarity, the various parts in the drawings are not drawn to scale.

[0032] Specifically, as described in the following specific embodiments:

[0033] Embodiment 1:

[0034] Figure 1 It is a schematic diagram of the device structure of the first embodiment of the utility model.

[0035] like Figure 1 As shown, in this embodiment, a coal-fired boiler flue gas waste heat recovery device includes: a coal-fired boiler 1, an economizer 2, a spray tower 3, an absorption heat pump 4, and a valve 5.

[0036] The absorption heat pump includes a generator G, a condenser C, an evaporator E, and an absorber A.

[0037] The flue gas generated by the coal-fired boiler 1 passes through the economizer 2 and the spray tower 3 in sequence, and is discharged into the environment after being cooled.

[0038] The return water of the heat network passes through the absorber A and condenser C of the absorption heat pump 4 in sequence. After preliminary heating, part of the water enters the economizer through the water side inlet 203 of the economizer 2, heats up in the economizer 2, and then enters the coal-fired boiler 1 through the hot water inlet 102 of the coal-fired boiler 1. The other part of the water flows through the valve 5 and enters the coal-fired boiler 1 through the hot water inlet 102 of the coal-fired boiler 1. The water heated in the coal-fired boiler 1 is provided to the heat users as heat network water.

[0039] A portion of the hot water flowing out of the water side outlet 204 of the economizer 2 enters the absorption heat pump generator G through the heat source inlet G01 of the absorption heat pump generator G, and serves as a driving heat source for the absorption heat pump 4. After cooling, it flows out through the heat source outlet G02 and enters the coal-fired boiler 1 through the hot water inlet 102 of the coal-fired boiler to be heated.

[0040] The outlet E02 of the evaporator E of the absorption heat pump 4 is connected to the inlet 303 of the spray tower 3. The cold water produced by the absorption heat pump 4 contacts the flue gas in the spray tower 3 for heat exchange, flows out from the spray tower outlet 304 after being heated, and returns to the evaporator E of the absorption heat pump 4.

[0041] In this embodiment, the water flow rate entering the economizer 2 is reduced by adjusting the valve 5, thereby increasing the outlet water temperature of the economizer 2, and using a portion of the high-temperature outlet water of the economizer 2 as the driving heat source of the absorption heat pump 4, thereby improving the energy utilization efficiency of the device.

[0042] Embodiment 2:

[0043] Figure 2 It is a schematic diagram of the device structure of the second embodiment of the utility model.

[0044] The difference from Example 1 is that, in this embodiment, after the water heated in the economizer 2 flows out of the economizer 2, a part of it enters the generator G of the absorption heat pump 4 as a driving heat source, and the other part is connected to the heat network water supply pipeline, mixed with the hot water at the outlet of the coal-fired boiler 1, and then provided to the heat users.

[0045] Compared with Example 1, the outlet water temperature of the economizer 2 in this embodiment is higher, and the water side outlet 204 of the economizer 2 is connected to the hot water outlet 103 of the coal-fired boiler, which reduces the water flow entering the coal-fired boiler, thereby reducing the flow resistance inside the boiler and improving the hydraulic conditions in the furnace.

[0046] Embodiment three:

[0047] Figure 3 It is a schematic diagram of the device structure of the third embodiment of the present utility model.

[0048] The difference from the second embodiment is that, in this embodiment, the condenser outlet C02 of the absorption heat pump 4 is connected to the heating network water supply pipe. After the heating network return water is heated in the absorption heat pump 4, it flows out from the condenser outlet C02 and is provided to users as heating network water supply.

[0049] Compared with Example 2, in this embodiment, the return water from the heating network enters the absorption heat pump and the coal-fired boiler in parallel, which further reduces the water flow entering the boiler and improves the overall operating efficiency of the system.

[0050] Embodiment 4:

[0051] Figure 4It is a schematic diagram of the device structure of the fourth embodiment of the present utility model.

[0052] The difference from the first embodiment is that this embodiment further includes a flue gas heat exchanger 6 .

[0053] After the flue gas is cooled in the economizer 2, it enters the flue gas heat exchanger 6 for further cooling. The water heated on the water side of the flue gas heat exchanger 6 enters the generator G of the absorption heat pump 4, serving as the driving heat source of the absorption heat pump 4. After cooling, it flows out through the generator heat source outlet G02 of the absorption heat pump 4 and returns to the flue gas heat exchanger 6.

[0054] The flue gas after passing through the flue gas heat exchanger 6 enters the spray tower 3 and is discharged into the atmosphere after further cooling.

[0055] Compared with Example 1, in this embodiment, water serving as a heat source driving the absorption heat pump exchanges heat with the flue gas through the flue gas heat exchanger 6, thereby reducing the heat exchange load demand on the economizer 2 and reducing the impact on the original coal-fired boiler smoke and air system.

[0056] The present invention has been described above with reference to the embodiments of the present invention. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, a person skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A coal-fired boiler flue gas waste heat recovery device, characterized in that: include: Coal-fired boiler (1), economizer (2), spray tower (3), absorption heat pump (4), valve (5); The absorption heat pump (4) comprises a generator (G), a condenser (C), an evaporator (E), and an absorber (A); The flue gas outlet (101) of the coal-fired boiler (1) is connected to the flue gas inlet (201) of the economizer (2), and the flue gas outlet (202) of the economizer (2) is connected to the flue gas inlet (301) of the spray tower (3); The return water from the heating network is connected to the inlet (A01) of the absorber (A) of the absorption heat pump (4), the outlet (A02) of the absorber (A) of the absorption heat pump (4) is connected to the inlet (C01) of the condenser (C) of the absorption heat pump (4), the outlet (C02) of the condenser (C) of the absorption heat pump (4) is connected to the inlet (501) of the valve (5), the outlet (502) of the valve (5) is connected to the hot water inlet (102) of the coal-fired boiler (1), and the hot water outlet (103) of the coal-fired boiler (1) is connected to the water supply of the heating network; The heat network return water is connected to the water side inlet (203) of the economizer (2), and the water side outlet (204) of the economizer (2) is connected to the hot water inlet (102) of the coal-fired boiler (1); The water-side outlet (204) of the economizer (2) is connected to the heat source inlet (G01) of the generator (G) of the absorption heat pump (4), and the heat source outlet (G02) of the generator (G) of the absorption heat pump (4) is connected to the water-side inlet (203) of the economizer (2); The outlet (E02) of the evaporator (E) of the absorption heat pump (4) is connected to the inlet (303) of the spray tower (3), and the outlet (304) of the spray tower (3) is connected to the inlet (E01) of the evaporator (E) of the absorption heat pump (4).

2. A coal-fired boiler flue gas waste heat recovery device as claimed in claim 1, characterized in that: The water side outlet (204) of the economizer (2) is connected to the water supply of the heating network.

3. A coal-fired boiler flue gas waste heat recovery device as claimed in claim 2, characterized in that: The outlet (C02) of the condenser (C) of the absorption heat pump (4) is connected to the water supply of the heating network.

4. A coal-fired boiler flue gas waste heat recovery device as claimed in claim 1, characterized in that: Also includes a flue gas heat exchanger (6); The flue gas outlet (202) of the economizer (2) is connected to the flue gas inlet (601) of the flue gas heat exchanger (6), and the flue gas outlet (602) of the flue gas heat exchanger (6) is connected to the flue gas inlet (301) of the spray tower (3); The water side outlet (604) of the flue gas heat exchanger (6) is connected to the heat source inlet (G01) of the generator (G) of the absorption heat pump (4), and the heat source outlet (G02) of the generator (G) of the absorption heat pump (4) is connected to the water side inlet (603) of the flue gas heat exchanger (6).

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