Semi-dry desulfurization system for low-temperature flue gas

Abstract

The utility model discloses a low-temperature flue gas semi-dry desulfurization system, and relates to the technical field of circulating fluidized bed semi-dry desulfurization processes. The desulfurization absorption tower comprises an inlet section, a transition section, an acceleration section, a diffusion section and a reaction section in sequence from a flue gas inlet to a flue gas outlet, the flue gas outlet is connected to a bag-type dust collector through a flue gas pipeline, the transition section is connected with a desulfurizer feeding air chute used for feeding a desulfurizer into the tower, and the reaction section is connected with a flue gas pipeline. The diffusion section is connected with a desulfurizer circulating air chute, the other end of the desulfurizer circulating air chute is connected to an ash discharge port of the bag-type dust collector, a water spraying mechanism is further arranged in the middle of the desulfurizer circulating air chute and used for adding water required by desulfurization reaction, and a plurality of water spraying ports are formed along the desulfurizer circulating air chute; according to the utility model, invalid evaporation of water in a flue gas environment in the tower is avoided, water consumption and flue gas temperature drop in the desulfurization process are greatly reduced, and the problems of wall sticking and bag pasting easily caused by traditional semi-dry desulfurization under a low-temperature flue gas condition can be avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to circulating fluidized bed semi-dry desulfurization process technical field, concretely is a kind of low-temperature flue gas semi-dry desulfurization system. BACKGROUND

[0002] CFB (circulating fluidized bed) semi-dry desulfurization technology is the more widely used flue gas SO2 treatment technology, with the advantages of high SO2 removal efficiency, higher exhaust gas temperature, and no waste water generation.CFB desulfurization process needs water to participate in desulfurization reaction, make the reaction of SO2 in flue gas and desulfurizer Ca (OH) 2 into ion type reaction that can be completed instantaneously, improve reaction efficiency, while the water attached to desulfurizer gradually evaporates in the reaction process, with the purified flue gas emission.

[0003] Traditional CFB semi-dry desulfurization process is provided with water spraying mechanism (water gun) on the desulfurization absorption tower body, for adding water required for desulfurization reaction;But in the flue gas environment in absorption tower, most of the sprayed water is evaporated by flue gas, only a small amount of water is attached to desulfurizer to participate in desulfurization reaction, thus resulting in large water consumption and flue gas temperature drop.In order to avoid the adverse effects of subsequent bag filter to produce "paste bag", relevant specification (HJ178-2018 flue gas circulating fluidized bed method flue gas desulfurization engineering general technical specification) requires that the flue gas temperature at the outlet of absorption tower is higher than the dew point temperature by more than 10℃ (generally not less than 75℃), therefore, under low-temperature flue gas condition (80~100℃), the application of traditional CFB semi-dry desulfurization system is limited, and it is easy to appear problems such as wall sticking, paste bag caused by excessive water spraying.The above, urgently needs a kind of low-temperature flue gas semi-dry desulfurization system to solve this problem. UTILITY MODEL CONTENT

[0004] The utility model aims at providing a kind of low-temperature flue gas semi-dry desulfurization system to solve the problem that the existing circulating fluidized bed semi-dry desulfurization process is prone to excessive water spraying, resulting in wall sticking and paste bag.

[0005] To achieve the above object, the utility model provides the following technical scheme: a kind of low-temperature flue gas semi-dry desulfurization system, including desulfurization absorption tower, its tower body structure is sequentially from flue gas inlet to flue gas outlet inlet section, transition section, acceleration section, diffusion section and reaction section, flue gas outlet is connected to bag filter by flue gas pipeline, transition section is connected with desulfurizer feed air chute, for supplying desulfurizer into tower, diffusion section is connected with desulfurizer circulating air chute, its other end is connected to the dust discharging port of bag filter, for returning most of desulfurization ash to tower and recycling, desulfurizer circulating air chute middle part is also provided with water spraying mechanism for adding water required for desulfurization reaction, and its water spraying port is provided with multiple along desulfurizer circulating air chute.

[0006] Preferably, the water spraying mechanism consists of a main water supply pipe connected to multiple sets of water spraying units. The multiple sets of water spraying units are distributed at intervals along the desulfurizing agent circulating air inclined trough. Each set of water spraying units includes at least three dual-fluid nozzles. Each dual-fluid nozzle is connected to the main water supply pipe through a water supply branch pipe. The multiple dual-fluid nozzles of each set of water spraying units are respectively distributed on the two sides and the top surface of the upper shell of the desulfurizing agent circulating air inclined trough.

[0007] Preferably, the main water supply pipe of the spray mechanism is connected to a heating device for adjusting the water temperature of the spray.

[0008] Preferably, the main water supply pipe of the spraying mechanism is connected to a flow regulating valve to match the spraying volume with the desulfurizing agent circulation volume.

[0009] Preferably, the end of the desulfurizing agent feed air chute furthest from the desulfurization absorption tower is connected to a desulfurizing agent silo.

[0010] Preferably, the ash discharge port of the bag filter is connected to two ash discharge pipes, one of which is connected to the desulfurizing agent circulating air chute, and the other is connected to the desulfurization ash silo.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1. This low-temperature flue gas semi-dry desulfurization system replaces the traditional semi-dry desulfurization process by installing a water spray mechanism on the desulfurizing agent circulating air inclined chute, which requires water guns inside the desulfurization absorption tower. This allows the sprayed water to mix with the circulating desulfurizing agent before entering the tower, thus avoiding ineffective evaporation of water in the flue gas environment inside the desulfurization absorption tower. This significantly reduces water consumption and flue gas temperature drop during the desulfurization process, and avoids problems such as wall adhesion and bag clogging that are prone to occur in the traditional semi-dry desulfurization process under low-temperature flue gas conditions.

[0013] 2. This low-temperature semi-dry flue gas desulfurization system is easy to control the injected water temperature. Combined with the adjustment of the conventional fluidizing air temperature, it can ensure the smooth flow of materials in the desulfurizing agent circulating air chute and minimize the temperature drop of the flue gas caused by water spraying.

[0014] 3. This low-temperature semi-dry flue gas desulfurization system can adjust the ratio of water spray volume to desulfurizing agent circulation volume according to the flue gas desulfurization efficiency requirements, thereby making full use of water resources and reducing operating costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model;

[0016] Figure 2 This is a schematic diagram of one distribution implementation of the water spray mechanism in this utility model.

[0017] In the figure: 1-desulfurization absorption tower, 101-inlet section, 102-transition section, 103-acceleration section, 104-diffusion section, 105-reaction section; 2-bag dust collector, 3-desulfurizer feeding air chute, 4-desulfurizer bin, 5-desulfurizer circulating air chute, 6-desulfurized ash bin, 7-water spraying mechanism, 8-heating device. DETAILED DESCRIPTION

[0018] Reference Figure 1 A low-temperature flue gas semi-dry desulfurization system, comprising a desulfurization absorption tower 1, the tower body structure of which is sequentially provided with an inlet section 101, a transition section 102, an acceleration section 103, a diffusion section 104 and a reaction section 105 from the flue gas inlet to the flue gas outlet, the flue gas outlet is connected to a bag dust collector 2 through a flue gas pipeline, the transition section 102 is connected with a desulfurizer feeding air chute 3 for supplying desulfurizer into the tower, the diffusion section 104 is connected with a desulfurizer circulating air chute 5, the other end of which is connected to an ash discharge port of the bag dust collector 2 for returning most of the desulfurized ash into the tower for recycling, and a water spraying mechanism 7 is further arranged in the middle of the desulfurizer circulating air chute 5 for adding water required for desulfurization reaction, and a plurality of water spraying ports are arranged along the desulfurizer circulating air chute 5.

[0019] As Figure 2 shown, a more preferred embodiment of the water spraying mechanism 7 is as follows: a plurality of groups of water spraying units are connected by a main water supply pipe, the plurality of groups of water spraying units are distributed at intervals along the desulfurizer circulating air chute 5, each group of water spraying units comprises at least three double-fluid nozzles (the nozzles have good atomization effect, and other atomizing nozzles can also be used for replacement), each double-fluid nozzle is connected to the main water supply pipe through a water supply branch pipe, and the plurality of double-fluid nozzles of each group of water spraying units are respectively distributed on the two side surfaces and the top surface of the upper shell of the desulfurizer circulating air chute 5. Figure 2 The upper shell, the lower shell and the air-permeable layer in the above are all structures of the desulfurizer circulating air chute 5, the desulfurizer in the air chute is in a fluidized state, and the chute structure of the fluidized bed is a known technology, so it will not be described in detail; of course, the water spraying mechanism 7 can also adopt other arrangement forms, for example, only distributed along the side wall of the desulfurizer circulating air chute 5, only distributed along the top surface, alternately distributed on the two side surfaces, etc., but in order to better guarantee uniform mixing and ensure smooth flow of the material, the above more preferred embodiments have been verified to be suitable for adoption, and specific adjustments can also be made according to actual conditions.

[0020] In order to adjust the water temperature of the water spraying, further ensure the smooth flow of the material in the desulfurizer circulating air chute 5 and minimize the temperature drop of the flue gas caused by the water spraying, the main water supply pipe of the water spraying mechanism 7 can be further connected with a heating device 8, and specific reference can be made to Figure 1 The heating device 8 can adopt a steam heat exchanger, an electric heater, etc., for reference, the water temperature interval of the water spraying can be controlled to be 50-80℃.

[0021] In addition, the main water supply pipe of the water spraying mechanism 7 can be connected with a flow regulating valve for matching the water spraying amount with the desulfurizer circulating amount.

[0022] In a preferred embodiment, the desulfurizer feeding air chute 3 is connected with a desulfurizer bin 4 at the end far from the desulfurization tower 1, which is convenient for adding new desulfurizer.

[0023] In a preferred embodiment, the dust discharging port of the bag filter 2 is connected with two dust discharging pipelines, one of which is connected to the desulfurizer circulating air chute 5, and the other is connected with a desulfurized ash bin 6. The ash collected by the bag filter 2 is mostly returned to the desulfurization tower 1 through the desulfurizer circulating air chute 5, and a part of it is periodically discharged to the desulfurized ash bin 6 according to the emission condition, and a part of new desulfurizer is supplemented. Through multiple cycles, the utilization efficiency of the desulfurizer can be improved.

[0024] The above is only a preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be defined by the protection scope of the claims.

[0025] The parts not described in the present application are well-known technologies for those skilled in the art.

Claims

1. A low-temperature flue gas semi-dry desulfurization system comprising a desulfurization absorption tower (1), the tower body structure of which is sequentially composed of an inlet section (101), a transition section (102), an acceleration section (103), a diffusion section (104), and a reaction section (105) from the flue gas inlet to the flue gas outlet, and the flue gas outlet is connected to a bag-type dust collector (2) through a flue gas pipeline, characterized in that: The transition section (102) is connected with a desulfurizer feeding air chute (3) for feeding desulfurizer into the tower, the diffusion section (104) is connected with a desulfurizer circulating air chute (5) which is connected to the dust discharging port of the bag-type dust collector (2) at the other end for returning most of the desulfurization ash into the tower for recycling, and a water spraying mechanism (7) is further arranged in the middle of the desulfurizer circulating air chute (5) for adding water required by the desulfurization reaction, and the water spraying port is provided with multiple ones along the desulfurizer circulating air chute (5).

2. A low temperature flue gas semi-dry desulphurization system as claimed in claim 1, wherein: The water spraying mechanism (7) is composed of a main water supply pipe connected with multiple groups of water spraying units, the multiple groups of water spraying units are distributed at intervals along the desulfurizer circulating air chute (5), each group of water spraying units comprises at least three double-fluid nozzles, each double-fluid nozzle is communicated to the main water supply pipe through a water supply branch pipe, and multiple double-fluid nozzles of each group of water spraying units are respectively distributed on the two side surfaces and the top surface of the shell of the desulfurizer circulating air chute (5).

3. A low-temperature flue gas semi-dry desulfurization system according to claim 1 or 2, characterized in that: The main water supply pipe of the water spraying mechanism (7) is connected with a heating device (8) for adjusting the water temperature of the water spraying.

4. A low-temperature flue gas semi-dry desulfurization system according to claim 1 or 2, characterized in that: The main water supply pipe of the water spraying mechanism (7) is connected with a flow regulating valve for matching the water spraying amount with the desulfurizer circulating amount.

5. A low temperature flue gas semi-dry desulphurization system according to claim 1 or 2, characterized in that: The desulfurizer feeding air chute (3) is connected with a desulfurizer bin (4) at the end away from the desulfurization tower (1).

6. A low temperature flue gas semi-dry desulphurization system according to claim 1 or 2, characterized in that: The dust discharging port of the bag-type dust collector (2) is connected with two dust discharging pipelines, one is connected to the desulfurizer circulating air chute (5), and the other is connected with a desulfurization ash bin (6).

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