Flue gas waste heat comprehensive utilization system and boiler

Abstract

The utility model provides a flue gas waste heat comprehensive utilization system and a boiler, and belongs to the field of flue gas waste heat utilization systems. The problems that according to an existing flue gas waste heat recycling technology, flue gas cannot be fully recycled, and substandard flue gas cannot be directly discharged into the atmosphere are solved. The system comprises a low-temperature flue gas heat exchange device, a circulating water pump set, a reversing valve set, a power plant low-temperature heater, a heat supply network water pipe network, a first surface type heat exchanger and a second surface type heat exchanger, and the low-temperature flue gas heat exchange device is connected with the first surface type heat exchanger. The first surface type heat exchanger, the reversing valve set, the second surface type heat exchanger and the power plant low-temperature heater are sequentially connected in the heating season, and the first surface type heat exchanger, the reversing valve set and the heat supply network water pipe network are sequentially connected in the heating season. The device is mainly used for boiler flue gas waste heat recovery and utilization.

Description

Technical Field

[0001] The utility model belongs to the field of flue gas waste heat utilization systems, in particular to a flue gas waste heat comprehensive utilization system and a boiler. Background Art

[0002] A large amount of flue gas generated in the furnace of a power plant's gas-fired boiler still has a temperature of 150°C to 160°C after heat exchange and purification through a superheater, economizer, and air preheater, and contains a large amount of industrial waste heat. For the recovery and utilization of waste heat from low-temperature flue gas from gas-fired boilers, it is currently common to use some methods to replace the boiler's low-temperature heater or not to recover it, and the substandard flue gas is directly discharged into the atmosphere. Utility Model Content

[0003] In view of this, the utility model aims to propose a flue gas waste heat comprehensive utilization system and boiler to solve the problem that the existing flue gas waste heat recovery technology cannot fully recycle the flue gas and directly discharges the substandard flue gas into the atmosphere.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A flue gas waste heat comprehensive utilization system comprises a low-temperature flue gas heat exchange device, a circulating water pump group, a reversing valve group, a power plant low-temperature heater, a heating network water pipe network, a first surface heat exchanger and a second surface heat exchanger. The low-temperature flue gas heat exchange device is connected to the first surface heat exchanger. In the non-heating season, the first surface heat exchanger, the reversing valve group, the second surface heat exchanger and the power plant low-temperature heater are connected in sequence. In the heating season, the first surface heat exchanger, the reversing valve group and the heating network water pipe network are connected in sequence.

[0006] Furthermore, the circulating water pump group includes a primary water circulating water pump group and a secondary water circulating water pump group. The primary water circulating water pump group is arranged between the first surface heat exchanger and the low-temperature flue gas heat exchange device, and the secondary water circulating water pump group is arranged between the first surface heat exchanger and the reversing valve group.

[0007] Furthermore, the reversing valve group includes a first reversing valve and a second reversing valve. In the non-heating season, the first reversing valve is connected to the second surface heat exchanger, and in the heating season, the second reversing valve is connected to the heating network water pipe network.

[0008] Furthermore, the output end of the low-temperature flue gas heat exchange device is also connected to a chimney.

[0009] Furthermore, a constant pressure water replenishing device is provided between the low-temperature flue gas heat exchange device and the first surface heat exchanger.

[0010] Furthermore, it also includes a flue gas waste heat recovery control system, which is connected to the power plant DCS system.

[0011] Furthermore, a boiler includes a flue gas waste heat comprehensive utilization system, and the flue gas waste heat comprehensive utilization system is connected to the boiler exhaust port.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] 1. Solve the problem that the existing flue gas waste heat recovery technology cannot fully recycle the flue gas and directly discharges the substandard flue gas into the atmosphere.

[0014] 2. It can fully and effectively utilize the waste heat of the flue gas in the gas power plant boiler for heating and can continuously extract heat. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0016] Figure 1 It is a schematic diagram of a flue gas waste heat comprehensive utilization system described in the utility model;

[0017] 1- low-temperature flue gas heat exchange device, 2- constant-pressure water supply device, 3- primary water circulation pump group, 4- first surface heat exchanger, 5- secondary water circulation pump group, 6- reversing valve group, 7- chimney, 8- second surface heat exchanger, 9- power plant low-temperature heater, 10- heat network water pipe network. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely explain the technical solutions in the embodiments of the utility model. It should be noted that the embodiments and features in the embodiments of the utility model can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the utility model, not all of the embodiments.

[0019] Specific implementation method 1: See Figure 1The present embodiment is described as a system for comprehensive utilization of flue gas waste heat, comprising a low-temperature flue gas heat exchange device 1, a circulating water pump group, a reversing valve group 6, a power plant low-temperature heater 9, a heating network water pipe network 10, a first surface heat exchanger 4 and a second surface heat exchanger 8. The low-temperature flue gas heat exchange device 1 is connected to the first surface heat exchanger 4. In the non-heating season, the first surface heat exchanger 4, the reversing valve group 6, the second surface heat exchanger 8 and the power plant low-temperature heater 9 are connected in sequence. In the heating season, the first surface heat exchanger 4, the reversing valve group 6 and the heating network water pipe network 10 are connected in sequence. The circulating water pump group includes a primary water circulating water pump group 3 and a secondary water circulating water pump group 5. The primary water circulating water pump group 3 is arranged between the first surface heat exchanger 4 and the low-temperature flue gas heat exchange device 1, and the secondary water circulating water pump group 5 is arranged between the first surface heat exchanger 4 and the reversing valve group 6. The reversing valve group 6 includes a first reversing valve and a second reversing valve. In the non-heating season, the first reversing valve is connected to the second surface heat exchanger 8. In the heating season, the second reversing valve is connected to the heating network water pipe network 10. The low-temperature flue gas heat exchange device 1 is connected to the flue of the power plant.

[0020] The water side of the low-temperature flue gas heat exchanger 1 is connected to the surface heat exchanger by a primary water circulation pump group 3. The surface heat exchanger includes a first surface heat exchanger 4 and a second surface heat exchanger 8. The first surface heat exchanger 4 and the second surface heat exchanger 8 are separated by a reversing valve group 6. After the hot water is taken out of the low-temperature flue gas heat exchanger 1, it is sent to the first surface heat exchanger 4 by the circulating water pump group. The hot water source is closed-circulated between the low-temperature flue gas heat exchanger 1 and the first surface heat exchanger 4; the first surface heat exchanger 4, the secondary water circulation pump group 5, and the reversing valve group 6 send the secondary water to the heat network water pipe network 10 and the power plant low-temperature heater 9, which solves the problem that the existing flue gas waste heat recovery technology cannot fully recycle the flue gas and directly discharges the substandard flue gas into the atmosphere, and can fully and effectively utilize the waste heat of the flue gas of the gas power plant boiler for heating and can continuously extract heat.

[0021] During the non-heating season, the second reversing valve is closed and the first reversing valve is opened. The first surface heat exchanger 4, the reversing valve group 6, the second surface heat exchanger 8 and the power plant low-temperature heater 9 are connected in series, and the water sides circulate with each other to form a primary and secondary closed circulation system. The waste heat of the power plant boiler flue gas is transferred to the power plant condensate system through the first surface heat exchanger 4 and the second surface heat exchanger 8, replacing the power plant low-temperature heater 9.

[0022] During the heating season, the first reversing valve is closed and the second reversing valve is opened. The first surface heat exchanger 4, the reversing valve group 6 and the heating network water pipe network 10 are connected in series, and the water sides circulate with each other to form a primary and secondary closed circulation system. The waste heat of the power plant boiler flue gas is transferred to the heating network water pipe network 10 through the first surface heat exchanger 4 to increase the water temperature of the heating network.

[0023] Specific implementation method 2: See Figure 1 To illustrate this embodiment, the output end of the low-temperature flue gas heat exchange device 1 is also connected to a chimney 7, and the flue gas that meets the standards after passing through the low-temperature flue gas heat exchange device 1 is discharged into the atmosphere through the chimney 7, thereby avoiding air pollution.

[0024] Specific implementation method three: See Figure 1 To illustrate this embodiment, a constant-pressure water replenishment device 2 is provided between the low-temperature flue gas heat exchange device 1 and the first surface heat exchanger 4 , and the constant-pressure water replenishment device 2 can be used to replenish water in the circulation system.

[0025] Specific implementation method four: see Figure 1 This embodiment also includes a flue gas waste heat recovery control system, which is connected to the DCS system of the power plant. The operator can select two control states of working conditions in the system. The system is simple and easy to adjust. The operation can be completed in the control room only, which can realize the waste heat recovery with maximum benefits and avoid the water quality problem of condensate water contamination in the heating network.

[0026] Specific implementation method five: see Figure 1 The present embodiment describes a boiler, wherein the boiler comprises a flue gas waste heat comprehensive utilization system, and the flue gas waste heat comprehensive utilization system is connected to the boiler exhaust port.

[0027] The embodiments of the utility model disclosed above are only used to help explain the utility model. The embodiments do not describe all the details in detail, nor do they limit the utility model to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the utility model, so that technicians in the relevant technical field can well understand and use the utility model.

Claims

1. A flue gas waste heat comprehensive utilization system, characterized by: The invention comprises a low-temperature flue gas heat exchange device (1), a circulating water pump group, a reversing valve group (6), a power plant low-temperature heater (9), a heating network water pipe network (10), a first surface heat exchanger (4) and a second surface heat exchanger (8); the low-temperature flue gas heat exchange device (1) is connected to the first surface heat exchanger (4); in the non-heating season, the first surface heat exchanger (4), the reversing valve group (6), the second surface heat exchanger (8) and the power plant low-temperature heater (9) are connected in sequence; in the heating season, the first surface heat exchanger (4), the reversing valve group (6) and the heating network water pipe network (10) are connected in sequence.

2. The flue gas waste heat comprehensive utilization system according to claim 1, characterized in that: The circulating water pump group comprises a primary water circulating water pump group (3) and a secondary water circulating water pump group (5); the primary water circulating water pump group (3) is arranged between the first surface heat exchanger (4) and the low-temperature flue gas heat exchange device (1); and the secondary water circulating water pump group (5) is arranged between the first surface heat exchanger (4) and the reversing valve group (6).

3. The flue gas waste heat comprehensive utilization system according to claim 1, characterized in that: The reversing valve group (6) comprises a first reversing valve and a second reversing valve. In the non-heating season, the first reversing valve is connected to the second surface heat exchanger (8), and in the heating season, the second reversing valve is connected to the heating network water pipe network (10).

4. The flue gas waste heat comprehensive utilization system according to claim 1, characterized in that: The output end of the low-temperature flue gas heat exchange device (1) is also connected to a chimney (7).

5. The flue gas waste heat comprehensive utilization system according to claim 1, characterized in that: A constant pressure water replenishment device (2) is provided between the low-temperature flue gas heat exchange device (1) and the first surface heat exchanger (4).

6. The flue gas waste heat comprehensive utilization system according to claim 1, characterized in that: It also includes a flue gas waste heat recovery control system, which is connected to the power plant DCS system.

7. A boiler, characterized in that: The boiler comprises the flue gas waste heat comprehensive utilization system according to any one of claims 1 to 6, and the flue gas waste heat comprehensive utilization system is connected to the boiler exhaust port.

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