Chain grate machine-rotary kiln pellet flue gas denitration device

Abstract

The utility model relates to a grate-rotary kiln pellet flue gas denitration device which comprises an inlet flue, an ammonia water spray gun, a dust remover, an inlet flue, a denitration reaction tower, an outlet flue, a circulating fan and an air return flue, a flue gas outlet of the dust remover is communicated with the top of the denitration reaction tower through an inlet flue, the bottom of the denitration reaction tower is connected with an air inlet of the circulating fan through an outlet flue, and an air outlet of the circulating fan is connected with one end of the air return flue; and the ammonia water spray gun is mounted on the inlet flue or / and the inlet flue. The ammonia water spray gun is arranged on the inlet flue, ammonia water sprayed into the flue can be evaporated into ammonia gas and water vapor under the action of flue gas temperature, the ammonia gas and the water vapor enter the denitration reaction tower after passing through the dust remover, and the dust remover plays a role of an ammonia-air mixer, so that ammonia and flue gas can be fully and uniformly mixed; the equipment and installation cost of the ammonia-air mixer is saved, the system resistance is reduced, and the denitration operation cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field related to flue gas denitration in the steel industry, and in particular to a chain grate machine-rotary kiln pelletizing flue gas denitration device. Background Art

[0002] The chain grate-rotary kiln is the leading production process for oxidation pellets in China. The chain grate is mainly divided into four parts: drying stage I, drying stage II, preheating stage I, and preheating stage II. The flue gas from the chain grate-rotary kiln pelletizing first undergoes SNCR denitrification + SCR denitrification. SNCR denitrification is completed in the bellows of the chain grate preheating stage II. The heat source of this stage comes from the 950-1150℃ hot air flow at the tail of the rotary kiln, and the temperature meets the SNCR denitrification temperature requirements. The SCR denitrification flue gas comes from the chain grate preheating stage II, and is sent back to the drying stage II by the circulating fan after passing through the dust collector and SCR denitrification.

[0003] The principle of SCR denitrification reaction is the redox reaction between ammonia and NOx in the flue gas. The denitrification agent uses 20% ammonia water. The conventional process is that the ammonia water evaporates in the ammonia water evaporator to generate ammonia, which is then sprayed through the ammonia spray grid equipment installed in the denitrification inlet flue to make ammonia react with NOx in the flue gas under the action of the catalyst. This requires an additional ammonia evaporation system with a complex and cumbersome structure. Utility Model Content

[0004] In order to solve one or more technical problems existing in the prior art, the utility model provides a chain grate machine-rotary kiln pelletizing flue gas denitrification device.

[0005] The utility model solves the above-mentioned technical problem with the following technical solution: a chain grate-rotary kiln pelletizing flue gas denitrification device, comprising an inlet flue, an ammonia spray gun, a dust collector, an inlet flue, a denitrification reaction tower, an outlet flue, a circulating fan and a return air flue, wherein the inlet flue is connected and communicated with the flue gas inlet of the dust collector, the flue gas outlet of the dust collector is communicated with the top of the denitrification reaction tower through the inlet flue, the bottom of the denitrification reaction tower is connected and communicated with the air inlet of the circulating fan through the outlet flue, and the air outlet of the circulating fan is connected and communicated with one end of the return air flue; the ammonia spray gun is installed on the inlet flue and / or the inlet flue.

[0006] The beneficial effects of the utility model are as follows: the chain grate machine-rotary kiln pelletizing flue gas denitrification device of the utility model, by arranging an ammonia spray gun on the inlet flue, the ammonia sprayed into the flue can evaporate into ammonia gas and water vapor under the action of the flue gas temperature, and then enter the denitrification reaction tower after passing through the dust collector. The dust collector plays the role of an ammonia-air mixer, which can make ammonia and flue gas fully and evenly mixed, saving the equipment and installation costs of the ammonia-air mixer, reducing the system resistance, saving the operating electricity consumption, and thus reducing the denitrification operating cost.

[0007] On the basis of the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, there are one or more ammonia spray guns, and the multiple ammonia spray guns are evenly distributed on the inlet flue and / or the entrance flue, and the spraying direction of the ammonia spray gun conforms to the flow direction of the flue gas in the inlet flue or the entrance flue.

[0009] Furthermore, a plurality of ammonia spray guns are arranged in a plurality of rows along the axial direction of the inlet flue or / and the outlet flue, and the ammonia spray guns in each row are arranged circumferentially staggered with the ammonia spray guns in an adjacent row.

[0010] Furthermore, the spray angle of the ammonia spray gun can cover more than 80% of the cross-sectional area of ​​the inlet flue or the entrance flue.

[0011] The beneficial effect of adopting the above further scheme is: making the ammonia water contact with the flue more fully and reducing the ammonia water gasification time.

[0012] Furthermore, the spray angle of the ammonia spray gun is fan-shaped 20° to 75°, or a single-hole solid cone 20° to 75°, or a multi-hole solid cone 20° to 75°.

[0013] Furthermore, a distributor is provided on the inner side of the top of the denitration reaction tower.

[0014] The beneficial effect of adopting the above further solution is that the provision of the uniform distributor can make the flue gas entering the denitration reaction tower evenly distributed.

[0015] Furthermore, multiple layers of catalyst packing layers are arranged in the denitration reaction tower.

[0016] Furthermore, a plurality of rake soot blowers are arranged in the denitration reaction tower, and a group of rake soot blowers is arranged above each catalyst packing layer.

[0017] The beneficial effect of adopting the above further scheme is that the catalyst soot blowing equipment adopts a rake soot blower, and the soot blowing medium is nitrogen or compressed air. Since the flue gas is high-dust flue gas, an ash discharge port is set at the bottom of the denitration reaction tower to facilitate the discharge of the deposited ash at the bottom of the reaction tower.

[0018] Furthermore, the denitration reaction tower is provided with two, three or four catalyst packing layers.

[0019] Furthermore, the circulating fan is a heat-resistant circulating fan; the outlet flue is arranged horizontally, and the denitrification reaction tower is arranged vertically, and the angle between the outlet flue and the denitrification reaction tower can be slightly adjusted according to the project situation; the inlet flue is a dust collector inlet flue, and the dust collector is a multi-tube dust collector or a cyclone dust collector. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the utility model of the chain grate machine-rotary kiln pelletizing flue gas denitrification device.

[0021] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0022] 1. Inlet flue; 2. Ammonia spray gun; 3. Dust collector; 4. Inlet flue; 5. Denitrification reaction tower; 6. Outlet flue; 7. Circulation fan; 8. Return air flue; 9. Distributor; 10. Catalyst packing layer; 11. Rake soot blower. DETAILED DESCRIPTION

[0023] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0024] like Figure 1 As shown, a chain grate-rotary kiln pelletizing flue gas denitrification device of the present embodiment comprises an inlet flue 1, an ammonia spray gun 2, a dust collector 3, an inlet flue 4, a denitrification reaction tower 5, an outlet flue 6, a circulating fan 7 and a return air flue 8, wherein the inlet flue 1 is connected and communicated with the flue gas inlet of the dust collector 3, the flue gas outlet of the dust collector 3 is communicated with the top of the denitrification reaction tower 5 through the inlet flue 4, the bottom of the denitrification reaction tower 5 is connected and communicated with the air inlet of the circulating fan 7 through the outlet flue 6, and the air outlet of the circulating fan 7 is connected and communicated with one end of the return air flue 8; the ammonia spray gun 2 is installed on the inlet flue 1 and / or the inlet flue 4.

[0025] like Figure 1 As shown, the ammonia spray gun 2 of this embodiment is one or more, and the multiple ammonia spray guns 2 are evenly distributed on the inlet flue 1 and / or the inlet flue 4. The spray direction of the ammonia spray gun 2 conforms to the flow direction of the flue gas in the inlet flue 1 or the inlet flue 4. One or more ammonia spray guns can be arranged according to the needs of the project.

[0026] Specifically, a plurality of ammonia spray guns 2 are arranged in a plurality of rows along the axial direction of the inlet flue 1 and / or the inlet flue 4 , and the ammonia spray guns 2 in each row are circumferentially staggered with the ammonia spray guns 2 in an adjacent row.

[0027] A preferred solution of this embodiment is that the spray angle of the ammonia spray gun 2 can cover more than 80% of the cross-sectional area of ​​the inlet flue 1 or the inlet flue 4, so that the ammonia water can contact the flue more fully and reduce the ammonia water gasification time.

[0028] Optionally, the spray angle of the ammonia spray gun is fan-shaped 20° to 75°, single-hole solid cone 20° to 75°, or multi-hole solid cone 20° to 75°. Preferably, the spray angle of the ammonia spray gun 2 is fan-shaped 60°, single-hole solid cone 60°, or multi-hole solid cone 55°.

[0029] like Figure 1 As shown, a distributor 9 is provided inside the top of the denitration reaction tower 5 of this embodiment. The arrangement of the distributor can make the flue gas entering the denitration reaction tower evenly distributed.

[0030] like Figure 1 As shown, the denitration reaction tower 5 of this embodiment is provided with multiple catalyst packing layers 10 .

[0031] like Figure 1 As shown, the denitration reaction tower 5 of this embodiment is equipped with a plurality of rake soot blowers 11 using compressed air or inert gas as a purge medium, and a group of rake soot blowers 11 is provided above each catalyst packing layer 10. The catalyst soot blowing equipment uses a rake soot blower, and the soot blowing medium is nitrogen or compressed air. Since the flue gas is high-dust flue gas, an ash discharge port is provided at the bottom of the denitration reaction tower to facilitate the discharge of the ash deposited at the bottom of the reaction tower.

[0032] like Figure 1 As shown, a preferred solution of this embodiment is that two, three or four catalyst packing layers 10 are provided in the denitration reaction tower 5 .

[0033] Specifically, the circulation fan 7 is a heat-resistant circulation fan.

[0034] Specifically, Figure 1 As shown, the outlet flue 6 is arranged horizontally, and the denitrification reaction tower 5 is arranged vertically. The angle between the outlet flue 6 and the denitrification reaction tower 5 can be slightly adjusted according to the project situation; the inlet flue 1 is the dust collector inlet flue, and the dust collector 3 is a multi-tube dust collector or a cyclone dust collector.

[0035] In this embodiment, the desulfurized flue gas is the flue gas after passing through the electrostatic precipitator. The flue gas of the electrostatic precipitator is drawn out from the drying stage I, the drying stage II, and the preheating stage I. The desulfurization adopts the lime-gypsum wet process. Compared with the desulfurized flue gas volume, denitrification belongs to semi-flue gas denitrification, because the SCR denitrification flue gas volume is less than half of the desulfurized flue gas volume. The device of this embodiment adopts semi-flue gas denitrification with a small flue gas volume. The equipment selection of the entire denitrification system is small, the flue size is small, and the land occupation is small, which not only saves construction costs, but also reduces operating costs. The temperature of the SCR denitrification flue gas is controlled at 350-420℃, and the flue gas is dusted by a multi-tube dust collector in front. The denitrification catalyst adopts a high-temperature and high-dust type. The catalyst soot blowing equipment adopts a rake soot blower, and the soot blowing medium is nitrogen or compressed air.

[0036] The denitration device of this embodiment adopts SCR denitration. The reaction principle of SCR denitration is that ammonia and NOx in flue gas undergo redox reaction. The denitrification agent adopts 20% ammonia water. The conventional process is that ammonia water evaporates in an ammonia water evaporator to generate ammonia, and then is sprayed into the flue through the ammonia spray grid device installed in the flue of the denitration inlet, so that ammonia and NOx in the flue gas react under the action of a catalyst. Since the flue gas temperature of the flue of the denitration inlet involved in this embodiment is 350-420℃, ammonia water is sprayed into the flue through a spray gun, and the flue gas can be used as a heat source to directly evaporate the ammonia water, and there is no need to set up a separate ammonia evaporation system, which reduces the construction cost and occupies less space.

[0037] The chain grate-rotary kiln pelletizing flue gas denitrification device of this embodiment has an ammonia spray gun arranged on the inlet flue. The ammonia sprayed into the flue can evaporate into ammonia gas and water vapor under the action of the flue gas temperature, and then enter the denitrification reaction tower after passing through the dust collector. The dust collector plays the role of an ammonia-air mixer, which can fully and evenly mix ammonia and flue gas, saving the equipment and installation costs of the ammonia-air mixer, reducing the system resistance, saving the operating electricity consumption, and thus reducing the denitrification operating cost.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0042] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0043] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A chain grate-rotary kiln pelletizing flue gas denitrification device, characterized in that: It includes an inlet flue, an ammonia spray gun, a dust collector, an inlet flue, a denitration reaction tower, an outlet flue, a circulating fan and a return air flue, wherein the inlet flue is connected and communicated with the flue gas inlet of the dust collector, the flue gas outlet of the dust collector is communicated with the top of the denitration reaction tower through the inlet flue, the bottom of the denitration reaction tower is connected and communicated with the air inlet of the circulating fan through the outlet flue, and the air outlet of the circulating fan is connected and communicated with one end of the return air flue; the ammonia spray gun is installed on the inlet flue and / or the inlet flue.

2. The chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 1, characterized in that: There are one or more ammonia spray guns, which are evenly distributed on the inlet flue and / or the entrance flue. The spraying direction of the ammonia spray guns conforms to the flow direction of the flue gas in the inlet flue or the entrance flue.

3. The chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 2, characterized in that: A plurality of ammonia spray guns are arranged in a plurality of rows along the axial direction of the inlet flue or / and the inlet flue, and the ammonia spray guns in each row are arranged circumferentially staggered with the ammonia spray guns in an adjacent row.

4. The chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 1, characterized in that: The spray angle of the ammonia spray gun is fan-shaped 20° to 75°, single-hole solid cone 20° to 75°, or multi-hole solid cone 20° to 75°.

5. The chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 1, characterized in that: A distributor is provided on the inner side of the top of the denitration reaction tower.

6. The chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 1, characterized in that: The denitration reaction tower is provided with multiple catalyst packing layers.

7. A chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 6, characterized in that: The denitration reaction tower is equipped with multiple groups of rake-type soot blowers using compressed air or inert gas as the purge medium, and a group of rake-type soot blowers is arranged above each catalyst packing layer.

8. The chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 6, characterized in that: The denitration reaction tower is provided with two, three or four catalyst packing layers.

9. The chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 1, characterized in that: The circulating fan is a heat-resistant circulating fan.

10. The chain grate-rotary kiln pelletizing flue gas denitrification device according to claim 1, characterized in that: The outlet flue is arranged horizontally, and the denitration reaction tower is arranged vertically; the dust collector is a multi-tube dust collector or a cyclone dust collector.

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