Multi-stage recovery device for flue gas waste heat of gas-fired boiler

Abstract

The utility model relates to the technical field of boiler flue gas waste heat, in particular to a gas-fired boiler flue gas waste heat multi-stage recovery device which comprises a multi-stage recovery device body, and the multi-stage recovery device body comprises a boiler body, a heat supply network water condenser, an air inlet condenser, an air enthalpy adding device and an overheating demister. The energy saver is arranged at the exhaust end of the boiler body, high-temperature flue gas passing through the energy saver sequentially passes through the heat supply network water condenser and the air inlet condenser for heat exchange, multi-stage heat exchange cooling is achieved, the flue gas temperature can be reduced to 25 DEG C, collected heat is used for heating first-network return water and air at an inlet of a combustor, gas combustion heat loss is reduced, and energy is saved. Meanwhile, the system can collect a large amount of condensate water, and a large amount of production water can be provided for a boiler system through alkali treatment. In addition, the waste heat recovery system is good in corrosion resistance, the problem of low-temperature corrosion of flue gas is solved, and the waste heat recovery system is reliable and stable in operation and long in service life.

Description

Technical Field

[0001] The utility model relates to the technical field of boiler flue gas waste heat, in particular to a multi-stage recovery device for flue gas waste heat of a gas boiler. Background Art

[0002] In recent years, with the continued rapid economic growth and the continuous improvement of residents' living standards, my country's demand for heating power for both industrial and residential use has continued to grow rapidly. To achieve the primary goals of energy conservation and emission reduction, gas-fired heating has become the primary energy supplier and a key focus of energy conservation and consumption reduction efforts. Promoting refined energy conservation and consumption reduction management for gas-fired boilers and improving energy resource utilization will significantly boost the heating industry's market potential. Currently, gas-fired boilers are only equipped with economizers at the rear of the boiler. However, in actual operation, the flue gas exhaust temperature can still reach 70-80°C after passing through the economizer, resulting in a significant waste of resources. Utility Model Content

[0003] (1) Technical problems solved

[0004] In view of the deficiencies in the prior art, the utility model provides a multi-stage recovery device for waste heat from flue gas of a gas boiler.

[0005] (2) Technical solution

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a multi-stage recovery device for waste heat from flue gas of a gas-fired boiler, comprising a multi-stage recovery device body, wherein the multi-stage recovery device body comprises a boiler body, a hot water network condenser, an air intake condenser, an air enthalpy adder and a superheated demister, the gas output end of the boiler body is connected to the air inlet of the hot water network condenser, the air outlet of the hot water network condenser is connected to the inlet of the air intake condenser, the water inlet of the hot water network condenser is connected to the water outlet of the superheated demister, the air intake condenser outlet is connected to the chimney, the water inlet and outlet of the air intake condenser are both connected to the air enthalpy adder, and the water outlet of the hot water network condenser is connected to the filtered return water.

[0007] In order to facilitate the recovery of condensed water, the present invention is improved in that the multi-stage recovery device body also includes a condensed water neutralization tank, which collects condensed water generated during the operation of the hot network water condenser and the intake air condenser.

[0008] In order to increase the heat exchange efficiency, the present invention has the following improvements: the heat network water condenser and the air intake condenser are both provided with gas-liquid plates and shells.

[0009] Preferably, the gas-liquid plate shell is provided with several groups of gas channels and liquid channels.

[0010] Preferably, the corresponding gas channels are arranged horizontally to form exhaust pipes, and the corresponding liquid channels are arranged horizontally to form drain pipes, and the corresponding exhaust pipes and drain pipes are arranged in an up-and-down staggered manner.

[0011] (3) Beneficial effects

[0012] Compared with the existing technology, the utility model provides a multi-stage recovery device for waste heat from flue gas of a gas boiler, which has the following beneficial effects:

[0013] This gas-fired boiler flue gas waste heat multi-stage recovery device features an economizer installed at the exhaust end of the boiler body. High-temperature flue gas passing through the economizer sequentially exchanges heat through the hot water condenser and the inlet air condenser, achieving multi-stage heat exchange and cooling. The flue gas temperature can be reduced to 25°C. The collected heat is used to heat the primary return water and burner inlet air, reducing heat loss from gas combustion. The system also collects large amounts of condensed water, which, through alkaline treatment, can provide a large amount of production water for the boiler system. Furthermore, the waste heat recovery system exhibits excellent corrosion resistance, addressing the issue of low-temperature corrosion in flue gas. Furthermore, the system operates reliably and stably, with a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structural system of the utility model;

[0015] Figure 2 This is a schematic cross-sectional diagram of the gas-liquid plate shell structure of the utility model;

[0016] Figure 3 This is a schematic diagram of the gas-liquid plate-shell operation of the utility model structure.

[0017] In the figure: 1. Boiler body; 2. Hot water condenser; 3. Inlet condenser; 4. Air enthalpy adder; 5. Superheat demister; 6. Condensate neutralization tank; 7. Gas-liquid plate and shell; 8. Gas channel; 9. Liquid channel. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] See also Figure 1-3A multi-stage recovery device for waste heat from flue gas of a gas-fired boiler comprises a multi-stage recovery device body, the multi-stage recovery device body comprising a boiler body 1, a hot water network condenser 2, an air intake condenser 3, an air enthalpy adder 4 and a superheated demister 5, the gas output end of the boiler body 1 being connected to the air inlet of the hot water network condenser 2, the air outlet of the hot water network condenser 2 being connected to the inlet of the air intake condenser 3, the water inlet of the hot water network condenser 2 being connected to the water outlet of the superheated demister 5, the air outlet of the air intake condenser 3 being connected to a chimney, the water inlet and water outlet of the air intake condenser 3 being both connected to the air enthalpy adder 4, and the water outlet of the hot water network condenser 2 being connected to filtered return water;

[0020] An economizer is installed at the flue gas output end of the boiler body 1. The air inlet of the heating network water condenser 2 is connected to the economizer flue gas outlet, and the air outlet of the heating network water condenser 2 is connected to the inlet of the air inlet condenser 3. The water inlet of the heating network water condenser 2 is connected to the water outlet of the superheated demister 5, and the water outlet of the heating network water condenser 2 is connected to the return water of the boiler body 1. This device heats the return water of the heating network by absorbing the flue gas temperature.

[0021] The air outlet of the air inlet condenser 3 is connected to the chimney, and the water inlet and outlet of the air inlet condenser 3 are both connected to the air enthalpy adder 4. The outdoor cold air is heated by further absorbing the waste heat of the flue gas, thereby increasing the inlet temperature of the boiler body 1.

[0022] The air heated by the air enthalpy adder 4 enters the superheated demister 5, is heated again by the return water of the first network, and is separated from the gas and liquid at the same time, the air humidity is reduced, the intake air temperature is increased, and the air is sent to the boiler body 1.

[0023] The flue gas condensate neutralization tank 6 collects the condensate produced by the hot water condenser 2 and the air intake condenser 3 during operation, and neutralizes the condensate with alkali to make the pH value of the condensate weakly alkaline, thereby providing production water for the boiler body 1.

[0024] The outdoor air passes through the air enthalpy adder 4 and is heated to a temperature of about 38°C. It then enters the superheated demister 5 for further heating. The temperature of the air heated twice can reach about 40°C. It is mixed with natural gas and sent to the boiler body 1 for combustion. The flue gas generated by the combustion enters the economizer at the tail of the boiler body 1. The flue gas temperature at the economizer outlet is about 57°C. The flue gas at the economizer outlet enters the hot water condenser 2 of the hot network. The return water from the superheated demister 5 enters the intake condenser 3 to heat the hot water required by the air enthalpy adder 4. At this time, the flue gas temperature can reach about 25°C for discharge, completing the flue gas waste heat recovery of the entire unit.

[0025] In this embodiment, the hot network water condenser 2 and the air inlet condenser 3 are both provided with a gas-liquid plate shell 7, and several groups of gas channels 8 and liquid channels 9 are provided on the gas-liquid plate shell 7. The corresponding gas channels 8 are arranged horizontally to form exhaust pipes, and the corresponding liquid channels 9 are arranged horizontally to form drain pipes. The corresponding exhaust pipes and drain pipes are staggered up and down. By arranging the gas channels 8 and liquid channels 9 into exhaust pipes and drain pipes respectively, and adopting an up and down staggered arrangement, the contact area and time between the two media can be increased, thereby improving the heat exchange efficiency. The design of the up and down staggered arrangement makes the entire system more compact, can save installation space, and is particularly suitable for applications with limited space.

[0026] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0027] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0028] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0029] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gas boiler flue gas waste heat multi-stage recovery device, comprising a multi-stage recovery device body, characterized in that: The multi-stage recovery device body comprises a boiler body (1), a hot water network condenser (2), an air intake condenser (3), an air enthalpy adder (4) and a superheated demister (5); the gas output end of the boiler body (1) is connected to the air inlet of the hot water network condenser (2); the air outlet of the hot water network condenser (2) is connected to the inlet of the air intake condenser (3); the water inlet of the hot water network condenser (2) is connected to the water outlet of the superheated demister (5); the air outlet of the air intake condenser (3) is connected to a chimney; the water inlet and water outlet of the air intake condenser (3) are both connected to the air enthalpy adder (4); and the water outlet of the hot water network condenser (2) is connected to filtered return water.

2. A gas boiler flue gas waste heat multi-stage recovery device according to claim 1, characterized in that: The multi-stage recovery device body further comprises a condensed water neutralization tank (6), and the condensed water neutralization tank (6) collects condensed water generated during the operation of the hot water network condenser (2) and the air intake condenser (3).

3. The multi-stage recovery device for waste heat from flue gas of a gas-fired boiler according to claim 2, characterized in that: The hot network water condenser (2) and the air inlet condenser (3) are both provided with a gas-liquid plate shell (7).

4. A gas boiler flue gas waste heat multi-stage recovery device according to claim 3, characterized in that: The gas-liquid plate shell (7) is provided with a plurality of groups of gas channels (8) and liquid channels (9).

5. The multi-stage recovery device for waste heat from flue gas of a gas-fired boiler according to claim 4, characterized in that: The corresponding gas channels (8) are arranged horizontally to form exhaust pipes, and the corresponding liquid channels (9) are arranged horizontally to form drain pipes. The corresponding exhaust pipes and drain pipes are arranged in an upper and lower staggered manner.

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