Ammonia water evaporation system for low-temperature denitration

Abstract

The utility model relates to an ammonia water evaporation system for low-temperature denitration, which is applied to a desulfurization system, the desulfurization system comprises a hot blast stove, a smoke tube and an SCR (Selective Catalytic Reduction) reactor which are sequentially communicated, and comprises an air mixing assembly and an ammonia water evaporator, the air mixing assembly comprises an outer cylinder, an inner cylinder and a swirler arranged in the outer cylinder; the cyclone divides the interior of the outer cylinder into a first chamber and a second chamber, the first chamber is communicated with the smoke pipe, the second chamber is communicated with the SCR reactor, one end of the inner cylinder is communicated with the hot blast stove, the other end of the inner cylinder is closed and extends into the first chamber, a plurality of air holes communicated with the first chamber are formed in the outer wall of the inner cylinder, and the ammonia water evaporator is communicated with the air outlet; the high-temperature flue gas and the low-temperature flue gas are evenly mixed in the first cavity, the flue gas reaches the needed temperature after being mixed again through the cyclone and is fed into the ammonia water evaporator, the high-temperature flue gas and the low-temperature flue gas are evenly mixed, the heat exchange efficiency is high, and stable work of the ammonia water evaporator is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of environmental protection engineering, in particular to an ammonia water evaporation system for low-temperature denitration. Background Art

[0002] As the environmental situation becomes increasingly severe, flue gas desulfurization and denitrification have gradually received attention. At present, the selective catalytic reduction technology with high denitrification efficiency, mature and stable technology is widely used in metallurgy, electricity, chemical industry and other fields. The reducing agents used in this technology are urea, liquid ammonia and ammonia water. Using urea as a reducing agent has high pyrolysis cost and complicated process; liquid ammonia is strictly controlled and highly dangerous during use, so ammonia water is currently the most widely used reducing agent.

[0003] For example, the low-temperature SCR denitrification ammonia evaporation system proposed in the utility model patent with application number CN202321399142.0, wherein the low-temperature SCR denitrification part includes a denitrification flue, the denitrification flue has a flue gas inlet and a flue gas outlet, and the denitrification flue is provided with a direct-fired furnace, an ammonia injection grid and an SCR reactor in sequence along the flow direction of the gas; the ammonia evaporation part includes a high-temperature flue, a low-temperature flue and a mixed flue, the inlet of the high-temperature flue is connected to the outlet of the direct-fired furnace, the inlet of the low-temperature flue is connected to the outlet of the SCR reactor, the outlet of the high-temperature flue, the outlet of the low-temperature flue and the inlet of the mixed flue are connected through a pipeline mixer, the outlet of the mixed flue is connected to the ammonia injection grid, and a dilution fan and an ammonia evaporator are provided in sequence along the flow direction of the gas on the mixed flue, and the ammonia evaporation part also includes an ammonia spray gun, which is used to atomize ammonia and spray it into the ammonia evaporator.

[0004] However, the high-temperature flue gas and the low-temperature flue gas are not mixed evenly, and the heat exchange efficiency is low, so that part of the flue gas entering the ammonia evaporator does not reach the required temperature. Utility Model Content

[0005] In view of this, it is necessary to provide a low-temperature denitrification ammonia evaporation system to solve the problem of uneven mixing of high-temperature flue gas and low-temperature flue gas and low heat exchange efficiency, so that part of the flue gas entering the ammonia evaporator does not reach the required temperature.

[0006] The utility model provides an ammonia evaporation system for low-temperature denitration, which is applied to a desulfurization system. The desulfurization system comprises a hot blast furnace, a smoke pipe and an SCR reactor which are connected in sequence, and comprises an air mixing component and an ammonia evaporator. The air mixing component comprises an outer cylinder, an inner cylinder and a cyclone built in the outer cylinder. The cyclone divides the interior of the outer cylinder into a first chamber and a second chamber. The first chamber is connected to the smoke pipe, one end of the inner cylinder is connected to the hot blast furnace, and the other end is closed and extends into the first chamber. The outer wall of the inner cylinder is formed with a plurality of pores connected to the first chamber, and the ammonia evaporator is connected to the second chamber.

[0007] Furthermore, the outer tube is formed with a first air inlet and a second air inlet connected to the first chamber, and an air outlet connected to the second chamber and the ammonia evaporator, and the first air inlet, the cyclone and the air outlet are arranged in sequence along the length direction of the outer tube.

[0008] Furthermore, the plurality of air holes are evenly arranged along the circumference of the inner cylinder, and an angle is formed between an extending direction of the air holes and a direction in which the inner cylinder points toward the cyclone.

[0009] Furthermore, the plurality of air holes are evenly arranged along the circumference of the inner cylinder, and an angle is formed between the extension direction of the air holes and the corresponding tangent line of the inner cylinder.

[0010] Furthermore, the swirl direction of the swirler is arranged opposite to the extension direction of the pores.

[0011] Furthermore, the second air inlet is arranged along a direction tangent to the outer cylinder.

[0012] Furthermore, the air mixing assembly also includes a first air intake pipe, a first regulating valve installed on the first air intake pipe, a second air intake pipe and a second regulating valve installed on the second air intake pipe, the first air intake pipe connects the inner tube and the hot air furnace, and the second air intake pipe connects the first chamber of the outer tube and the smoke pipe.

[0013] Furthermore, the air outlet of the outer cylinder is a tapered tubular structure that gradually becomes smaller in a direction away from the cyclone.

[0014] Furthermore, it also includes an ammonia injection grid and a static mixer which are built into the smoke pipe and arranged in sequence along the airflow direction in the smoke pipe, and the discharge end of the ammonia evaporator is connected to the ammonia injection grid.

[0015] Furthermore, it also includes a plurality of dilution fans, and the ammonia evaporator is connected to the air outlet of the outer cylinder via the plurality of dilution fans.

[0016] Compared with the prior art, the high-temperature flue gas in the hot blast furnace can be evenly introduced into the first chamber through the multiple air holes on the inner cylinder, and the low-temperature flue gas is introduced into the first chamber. The high-temperature flue gas and the low-temperature flue gas are evenly mixed in the first chamber, and the flue gas reaches the required temperature after being mixed again by the cyclone, and is sent to the ammonia evaporator. The high-temperature flue gas and the low-temperature flue gas are evenly mixed, and the heat exchange efficiency is high, thereby ensuring the stable operation of the ammonia evaporator. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of the low-temperature denitrification ammonia evaporation system provided by the embodiment of the utility model as a whole applied to the desulfurization system;

[0018] Figure 2 A schematic diagram of the structure of the air mixing component in the low-temperature denitration ammonia evaporation system provided by the embodiment of the utility model;

[0019] Figure 3 A schematic diagram of the structure of an air mixing component in a low-temperature denitrification ammonia evaporation system provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0021] like Figure 1-3 As shown, the utility model provides an ammonia evaporation system for low-temperature denitrification, which is applied to a desulfurization system 100. The desulfurization system 100 includes a hot blast furnace 110, a smoke pipe 120 and an SCR reactor 130 connected in sequence, including an air mixing component 200 and an ammonia evaporator 300. The air mixing component 200 includes an outer cylinder 210, an inner cylinder 220 and a cyclone 230 built into the outer cylinder 210. The cyclone 230 divides the interior of the outer cylinder 210 into a first chamber and a second chamber. The first chamber is connected to the smoke pipe 120. One end of the inner cylinder 220 is connected to the hot blast furnace 110, and the other end thereof is closed and extends into the first chamber. The outer wall of the inner cylinder 220 is formed with a plurality of air holes 221 connected to the first chamber. The ammonia evaporator 300 is connected to the second chamber.

[0022] During implementation, the high-temperature flue gas in the hot blast furnace 110 can be uniformly introduced into the first chamber through the multiple air holes 221 on the inner cylinder 220, and the low-temperature flue gas is introduced into the first chamber. The high-temperature flue gas and the low-temperature flue gas are uniformly mixed in the first chamber, and the flue gas reaches the required temperature after being mixed again through the cyclone 230, and is sent to the ammonia evaporator 300. The high-temperature flue gas and the low-temperature flue gas are uniformly mixed, and the heat exchange efficiency is high, thereby ensuring the stable operation of the ammonia evaporator 300.

[0023] It should be noted that the above-mentioned desulfurization system 100 includes a hot air furnace 110, a smoke duct 120 and an SCR reactor 130 which are connected in sequence, and also includes an air inlet pipe 140 and an air outlet pipe 150. The hot air furnace 110 is connected to the outside air via the air inlet pipe 140, and the SCR reactor 130 discharges the air that has been subjected to denitrification treatment via the air outlet pipe 150.

[0024] The air mixing component 200 in this embodiment is a structure for mixing high-temperature flue gas and low-temperature flue gas. For example, the temperature of the high-temperature flue gas introduced into the air mixing component 200 from the hot blast furnace 110 is 1000°C, and the temperature of the low-temperature flue gas introduced into the air mixing component 200 from the smoke pipe 120 is 180°C. The high-temperature flue gas and the low-temperature flue gas are mixed in the air mixing component 200 to form a flue gas with a temperature of about 300°C, which can ensure the effective evaporation of ammonia water.

[0025] In one embodiment, the outer tube 210 is formed with a first air inlet 211 and a second air inlet 212 connected to the first chamber, and an air outlet 213 connected to the second chamber and the ammonia evaporator 300, and the first air inlet 211, the cyclone 230 and the air outlet 213 are arranged in sequence along the length direction of the outer tube 210.

[0026] In one embodiment, the plurality of air holes 221 are evenly arranged along the circumference of the inner cylinder 220 , and an angle is formed between the extending direction of the air holes 221 and the direction of the inner cylinder 220 pointing to the cyclone 230 .

[0027] In another embodiment, the plurality of air holes 221 are evenly arranged along the circumference of the inner cylinder 220 , and an angle is formed between the extending direction of the air holes 221 and the corresponding tangent line of the inner cylinder 220 .

[0028] The swirl direction of the cyclone 230 is opposite to the extension direction of the air hole 221, thereby increasing the turbulence in the first chamber of the outer tube 210. It can be understood that the extension direction of the air hole 221 is set to make the high-temperature flue gas entering the first chamber of the outer tube 210 dispersed more evenly.

[0029] A circular tube can be set at the above-mentioned air hole 221. The circular tube surrounding the inner cylinder 220 can realize uniform air intake of high-temperature flue gas, enhance airflow disturbance, and help to evenly mix the flue gas; the circular tube forms a certain angle with the inner cylinder 220, so that the low-temperature flue gas makes a swirling motion in the cylinder after entering, which can increase the residence time of the flue gas in the cylinder and improve the mixing degree of the flue gas. The reverse swirler 230 arranged at the rear end of the cylinder can further increase the mixing uniformity.

[0030] The cyclone 230 is made of 304 stainless steel. The cyclone 230 is welded and fixed to the outer cylinder 210. An insulation layer may be provided inside the outer cylinder 210 for heat insulation. The insulation layer may be made of, but not limited to, ceramic fiber wool insulation material.

[0031] To further improve the mixing effect of the high-temperature flue gas and the low-temperature flue gas, in one embodiment, the second air inlet 212 is arranged along a direction tangent to the outer cylinder 210 .

[0032] The air mixing assembly 200 in this embodiment further includes a first air intake pipe 211a, a first regulating valve 211b installed on the first air intake pipe 211a, a second air intake pipe 212a, and a second regulating valve 212b installed on the second air intake pipe 212a. The first air intake pipe 211a is connected to the inner tube 220 and the hot air stove 110, and the second air intake pipe 212a is connected to the first chamber of the outer tube 210 and the smoke pipe 120. By adjusting the first regulating valve 211b and the second regulating valve 212b, the amount of high-temperature flue gas and low-temperature flue gas entering the outer tube can be controlled, thereby controlling the temperature of the flue gas finally derived.

[0033] The second air intake pipe 212a and the outer tube 210 may be made of Q235 carbon steel, and the first air intake pipe 211a and the inner tube 220 may be made of 310S or other high temperature resistant materials.

[0034] In one embodiment, the air outlet 213 of the outer cylinder 210 is a tapered tubular structure that gradually becomes smaller in a direction away from the cyclone 230 .

[0035] Of course, the outer cylinder 210 may also adopt other shapes, which is not limited in the embodiment of the present utility model.

[0036] The ammonia water evaporator 300 in this embodiment is a structure for evaporating ammonia water that can be thought of by those skilled in the art.

[0037] It also includes an ammonia spray grid 310 and a static mixer 320 which are built into the smoke pipe 120 and arranged in sequence along the air flow direction in the smoke pipe 120 . The discharge end of the ammonia evaporator 300 is connected to the ammonia spray grid 310 .

[0038] In one embodiment, a plurality of dilution fans 400 are further included, and the ammonia evaporator 300 is connected to the air outlet 213 of the outer cylinder 210 via the plurality of dilution fans 400 .

[0039] Compared with the prior art: the high-temperature flue gas in the hot blast furnace 110 can be uniformly introduced into the first chamber through the multiple air holes 221 on the inner cylinder 220, and the low-temperature flue gas is introduced into the first chamber. The high-temperature flue gas and the low-temperature flue gas are uniformly mixed in the first chamber, and the flue gas reaches the required temperature after being mixed again through the cyclone 230, and is sent to the ammonia evaporator 300. The high-temperature flue gas and the low-temperature flue gas are uniformly mixed, and the heat exchange efficiency is high, thereby ensuring the stable operation of the ammonia evaporator 300.

[0040] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention.

Claims

1. A low-temperature denitrification ammonia evaporation system, applied to a desulfurization system, the desulfurization system comprises a hot blast furnace, a smoke pipe and an SCR reactor connected in sequence, characterized in that: include: An air mixing component, comprising an outer cylinder, an inner cylinder and a cyclone built in the outer cylinder, wherein the cyclone divides the interior of the outer cylinder into a first chamber and a second chamber, wherein the first chamber is connected to the smoke pipe, one end of the inner cylinder is connected to the hot blast stove, and the other end is closed and extends into the first chamber, and a plurality of air holes connected to the first chamber are formed on the outer wall of the inner cylinder; An ammonia water evaporator is communicated with the second chamber.

2. The low-temperature denitrification ammonia evaporation system according to claim 1, characterized in that: The outer cylinder is formed with a first air inlet and a second air inlet connected to the first chamber, and an air outlet connected to the second chamber and the ammonia evaporator. The first air inlet, the cyclone and the air outlet are arranged in sequence along the length direction of the outer cylinder.

3. The low-temperature denitrification ammonia evaporation system according to claim 2, characterized in that: The plurality of air holes are evenly arranged along the circumference of the inner cylinder, and an angle is formed between an extending direction of the air holes and a direction in which the inner cylinder points to the cyclone.

4. The low-temperature denitrification ammonia evaporation system according to claim 2, characterized in that: The plurality of air holes are evenly arranged along the circumference of the inner cylinder, and an angle is formed between the extension direction of the air holes and the corresponding tangent line of the inner cylinder.

5. The low-temperature denitrification ammonia evaporation system according to claim 4, characterized in that: The swirl direction of the swirler is arranged opposite to the extending direction of the air holes.

6. The low-temperature denitrification ammonia evaporation system according to claim 2, characterized in that: The second air inlet is arranged along a direction tangent to the outer cylinder.

7. The low-temperature denitrification ammonia evaporation system according to claim 1, characterized in that: The air mixing assembly also includes a first air intake pipe, a first regulating valve installed on the first air intake pipe, a second air intake pipe and a second regulating valve installed on the second air intake pipe, the first air intake pipe connects the inner tube and the hot air stove, and the second air intake pipe connects the first chamber of the outer tube and the smoke pipe.

8. The low-temperature denitrification ammonia evaporation system according to claim 1, characterized in that: The air outlet of the outer cylinder is a tapered tubular structure that gradually becomes smaller in a direction away from the cyclone.

9. The low-temperature denitrification ammonia evaporation system according to claim 1, characterized in that: It also includes an ammonia injection grid and a static mixer which are built into the smoke pipe and arranged in sequence along the airflow direction in the smoke pipe, and the discharge end of the ammonia evaporator is connected to the ammonia injection grid.

10. The low-temperature denitrification ammonia evaporation system according to claim 1, characterized in that: It also includes a plurality of dilution fans, and the ammonia evaporator is connected to the air outlet of the outer cylinder via the plurality of dilution fans.

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