Ammonia water evaporator device for steam heat exchange and SCR (Selective Catalytic Reduction) denitration system

Abstract

The utility model belongs to the technical field of ammonia water evaporators in environment-friendly SCR (Selective Catalytic Reduction) denitration systems, and particularly relates to a steam heat exchange ammonia water evaporator device and an SCR denitration system. The device comprises a vertically arranged evaporation tower, the bottom of the evaporation tower is provided with an air inlet, and the top of the evaporation tower is provided with a mixed gas outlet; the ammonia water spray gun is arranged at the bottom of the evaporation tower, and a nozzle of the ammonia water spray gun extends into the evaporation tower; the at least one heat exchange layer is arranged in the evaporation tower, and each heat exchange layer is positioned above the ammonia water spray gun. On the basis of the device, the reducing agent ammonia water can be fully sprayed into the ammonia water evaporator through the ammonia water spray gun after being fully atomized, is in contact with the heat exchange layer, is quickly gasified and is mixed with air at the bottom inlet, and ammonia-air mixed gas is output and is used for SCR (Selective Catalytic Reduction) denitration reaction.

Description

Technical Field

[0001] The utility model belongs to the technical field of ammonia water evaporators in environmentally friendly SCR denitration systems, and particularly relates to a steam heat exchange ammonia water evaporator device and an SCR denitration system. Background Art

[0002] Nitrogen oxides (NO x Nitrogen oxides (NOx) are produced by the high-temperature combustion of fossil fuels and air, causing significant environmental pollution. As a technological investment in treating nitrogen oxides, SCR denitrification projects can reduce NOx and directly mitigate its environmental pollution.

[0003] SCR denitrification is a widely used and effective denitrification technology. Using equipment such as ammonia evaporation and ammonia-air mixing, the resulting ammonia-air mixture is injected into the furnace through an ammonia injection grid, where it denitrifies under the action of a catalyst. It offers advantages such as minimal equipment, simple installation, ease of control, and excellent results.

[0004] At present, SCR technology is widely used and can greatly control NO x With the increase in capacity of each unit and the existing renovation projects, funding and available areas are limited. Therefore, it is more important to research more rational land planning and more economical SCR-related equipment.

[0005] For factories that use ammonia as a reducing agent, ammonia is usually passed through an ammonia evaporator and then into an ammonia-air mixer; or ammonia and hot flue gas are directly passed into the ammonia evaporator for direct evaporation. However, if there is not enough space in the factory or it is inconvenient to lead the hot flue gas down to be used as the heat source for the ammonia evaporator, hot air can also be used. However, the disadvantages of heat exchange equipment consuming electricity and space are gradually becoming apparent. Utility Model Content

[0006] In order to solve the deficiencies of the prior art, the utility model provides an ammonia evaporator device for steam heat exchange in an SCR denitration system, and an SCR denitration system.

[0007] The technical solutions provided by this utility model are as follows:

[0008] An ammonia evaporator device for steam heat exchange, comprising:

[0009] A vertically arranged evaporation tower, wherein the bottom of the evaporation tower is provided with an air inlet, and the top of the evaporation tower is provided with a mixed gas outlet;

[0010] an ammonia spray gun disposed at the bottom of the evaporation tower, the nozzle of the ammonia spray gun extending into the evaporation tower;

[0011] and at least one heat exchange layer is arranged in the evaporation tower, and each heat exchange layer is located above the ammonia spray gun.

[0012] Based on the above technical solution, the reducing agent ammonia water can be fully atomized through the ammonia water spray gun and then sprayed into the ammonia water evaporator, contacting with the heat exchange layer to achieve rapid gasification, and mixing with the air at the bottom inlet to output an ammonia-air mixed gas, which can be used as a reducing agent for the SCR denitrification reaction.

[0013] The ammonia spray gun has excellent atomization performance, ensuring uniform dispersion of the ammonia in the ammonia evaporator. The reductant droplets are fully atomized by the spray gun, and the atomized small-sized reductant fully contacts the steam coil, ensuring complete vaporization and dispersion. It then mixes with air, achieving ammonia-air mixing and concentration control.

[0014] The concentration of ammonia water can be around 15-20%.

[0015] Ammonia evaporator can be made of 304 or above material to ensure that the material is resistant to a certain degree of ammonia corrosion.

[0016] The air can be compressed air in the factory or diluted air from a dilution fan, and the pressure is slightly positive.

[0017] The evaporation tower is preferably cylindrical.

[0018] Specifically, the nozzle of the ammonia spray gun extends into the axis of the evaporation tower, and the angle bisector of the spray sprayed from the nozzle passes through the axis of the evaporation tower.

[0019] Based on the above technical solution, it is beneficial to the uniform distribution of the spray.

[0020] Specifically, the spray angle of the ammonia spray gun is 55-65°, preferably 60°.

[0021] The dilution air will have a certain convergence effect on the ammonia solution. Based on the above technical solution, it can avoid the impact of too small an angle on the coil, which will shorten its life, and avoid too large an angle on the ammonia evaporator tube wall.

[0022] Specifically, each heat exchange layer is a U-shaped heat exchange coil, and each U-shaped heat exchange coil is provided with a manual valve.

[0023] Based on the above technical solution, the number of heat exchange coil layers used can be appropriately increased or decreased according to the actual steam temperature used.

[0024] Furthermore, each heat exchange layer is a U-shaped heat exchange coil, and the inlet and outlet of each U-shaped heat exchange coil are provided with a hand valve, and the end is provided with a hydrophobic device.

[0025] Furthermore, the optimal number of U-shaped heat exchange coils is two layers, arranged in sequence from top to bottom. The heat exchange coils should be made of 316L or higher material to resist corrosion.

[0026] Furthermore, the horizontal projections of two adjacent U-shaped heat exchange coils are perpendicular to each other.

[0027] Preferably, the height difference between the bottommost U-shaped heat exchange coil and the ammonia spray gun is at least 30 cm.

[0028] Based on the above technical solution, it can be ensured that the ammonia water can reach the surface of the heat exchange element more evenly, which is also conducive to ensuring the service life of the coil.

[0029] Furthermore, a hand hole is provided above the heat exchange layer.

[0030] Furthermore, a support lug is provided in the middle of the evaporation tower.

[0031] The utility model also provides an SCR denitration system, comprising the steam heat exchange ammonia evaporator device, wherein the mixed gas outlet is connected to the ammonia injection grid, and the heat exchange layer is connected to the boiler steam pipe.

[0032] The mixed gas outlet provides an ammonia-air mixer with a concentration below 5%, which is used as a reducing agent for downstream SCR denitrification. The ammonia-air mixed gas enters the ammonia injection grid and is evenly mixed with the flue gas through the end nozzles covering the entire flue cross section.

[0033] The heat exchange layer comes from the steam from the factory boiler, etc., and the temperature should be above 220℃.

[0034] To produce a qualified ammonia-air mixture, the steam heat source must be at least 220°C. A suitable heat source can be obtained by connecting to the plant's medium- and high-temperature steam. The steam outlet must be properly drained.

[0035] The beneficial effects of the utility model include:

[0036] 1. It takes up less space and realizes the functions of ammonia evaporation and ammonia-air mixing through one device, thereby reducing energy consumption.

[0037] 2. The heat exchange efficiency can be adjusted according to actual working conditions, with high flexibility.

[0038] 3. The cross-arrangement between the heat exchange coil layers can disperse ammonia and air more evenly, which is conducive to the mixing of ammonia-air mixture and has better dispersion of the reducing agent when used for SCR denitrification. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the steam heat exchange ammonia evaporator device provided by the utility model.

[0040] Figure 2 It is the layout diagram of the U-shaped heat exchange coil.

[0041] Attachment Figure 1 、 2 The structures represented by each number are listed as follows:

[0042] 1. Air inlet; 2. Ammonia spray gun; 3. U-shaped heat exchange coil; 4. Hand hole; 5. Support lug; 6. Mixed gas outlet; 7. Hand valve. DETAILED DESCRIPTION

[0043] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0044] It should be noted that when a part or component is considered to be "connected to," "located on," or "assembled on" another part or component, it can be directly disposed on the other part or component or there may be a central part or component. The terms "left," "right," "upper," "lower," and similar expressions used herein are for illustrative purposes only.

[0045] The ammonia evaporator is made of 304 material.

[0046] The U-shaped heat exchange coil is made of 316L material.

[0047] Example 1

[0048] like Figure 1 As shown, the steam heat exchange ammonia evaporator device includes: a vertically arranged evaporation tower, an ammonia spray gun 2 arranged at the bottom of the evaporation tower, and at least two heat exchange layers arranged in the evaporation tower.

[0049] The evaporation tower is equipped with an air inlet 1 at its base and a mixed gas outlet 6 at its top. The nozzle of the ammonia spray gun 2 extends into the tower's axis, with the angle bisector of the spray spray passing through the tower's axis. Each heat exchange layer consists of a U-shaped heat exchange coil 3 equipped with a manual valve 7, located above the ammonia spray gun 2. The U-shaped heat exchange coils 3 are arranged in a sequential order, top and bottom.

[0050] Based on this technical solution, in the device, the spray from the ammonia spray gun can be quickly vaporized through the heat exchange layer and mixed with the air inlet at the bottom to output an ammonia-air mixed gas.

[0051] Example 2

[0052] On the basis of Example 1, Figure 2 As shown, the horizontal projections of two adjacent U-shaped heat exchange coils 3 are perpendicular to each other. In other embodiments, the angle between the horizontal projections of two adjacent U-shaped heat exchange coils 3 can be 80-90 degrees.

[0053] Based on this technical solution, the U-shaped heat exchange coils overlap with each other, which is beneficial to expand the heat exchange surface and disperse the ammonia, achieving a more uniform mixing of ammonia and air.

[0054] Example 3

[0055] Based on the above embodiments, Figure 1 As shown, a hand hole 4 may be provided above the heat exchange layer, and a support ear 5 may be provided in the middle of the evaporation tower.

[0056] Based on this technical solution, the maintenance and installation of the ammonia evaporator device with steam heat exchange are facilitated.

[0057] Example 4

[0058] The steam heat exchange ammonia evaporator device provided in Example 1 comprises a vertically arranged evaporation tower, an ammonia spray gun 2 disposed at the bottom of the tower, and at least two heat exchange layers within the tower. An air inlet 1 is provided at the bottom of the tower, and a mixed gas outlet 6 is provided at the top. The nozzle of the ammonia spray gun 2 extends into the axis of the tower, with the angle bisector of the spray sprayed from the nozzle passing through the axis of the tower. Each heat exchange layer comprises a U-shaped heat exchange coil 3 equipped with a manual valve 7.

[0059] The air in the air inlet is compressed air of about 5000Pa.

[0060] The spray angle of the ammonia spray gun 2 is 60°.

[0061] Ammonia concentration 15-20%.

[0062] The number of the U-shaped heat exchange coils 3 is three, and the horizontal projections of two adjacent U-shaped heat exchange coils 3 are perpendicular to each other.

[0063] The height difference between the lowermost U-shaped heat exchange coil 3 and the ammonia spray gun 2 is 30 cm.

[0064] The steam heat source of the U-shaped heat exchange coil 3 is 250°C steam.

[0065] The mixed gas outlet 6 outputs 5% ammonia-air mixed gas with a flow rate of 500Nm 3 / h.

[0066] Comparative Example 1

[0067] Referring to Example 4, the steam heat exchange ammonia evaporator device based on the steam heat exchange provided in Example 1 includes a vertically arranged evaporation tower, an ammonia spray gun 2 located at the bottom of the evaporation tower, and two heat exchange layers within the evaporation tower. An air inlet 1 is provided at the bottom of the evaporation tower, and a mixed gas outlet 6 is provided at the top of the evaporation tower. The nozzle of the ammonia spray gun 2 extends into the axis of the evaporation tower, and the angle bisector of the spray spray from the nozzle passes through the axis of the evaporation tower. Each heat exchange layer comprises a U-shaped heat exchange coil 3 equipped with a manual valve 7.

[0068] The difference is that the steam inlet heat source is 300℃, which can reduce the number of heat exchange layers without affecting the quality of the outlet ammonia-air mixture.

[0069] The mixed gas outlet 6 outputs 5% ammonia-air mixed gas with a flow rate of 500 Nm 3 / h.

[0070] Comparative Example 2

[0071] Referring to Example 4, the steam heat exchange ammonia evaporator device based on Example 1 includes a vertically arranged evaporation tower, an ammonia spray gun 2 located at the bottom of the evaporation tower, and three heat exchange layers within the evaporation tower. An air inlet 1 is provided at the bottom of the evaporation tower, and a mixed gas outlet 6 is provided at the top of the evaporation tower. The nozzle of the ammonia spray gun 2 extends into the axis of the evaporation tower, and the angle bisector of the spray spray from the nozzle passes through the axis of the evaporation tower. Each heat exchange layer comprises a U-shaped heat exchange coil 3 equipped with a manual valve 7.

[0072] The difference is that in order to ensure that the ammonia-air mixture has sufficient pressure to be sprayed into the flue cross section, the volume of the dilution air should be increased and the wind speed should be increased.

[0073] The mixed gas outlet 6 outputs 1% ammonia-air mixed gas with a flow rate of 2500 Nm 3 / h.

[0074] The above are only preferred embodiments of the present invention and do not constitute any form of limitation to the present invention. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A steam heat exchange ammonia evaporator device, characterized in that: include: A vertically arranged evaporation tower, wherein the bottom of the evaporation tower is provided with an air inlet (1), and the top of the evaporation tower is provided with a mixed gas outlet (6); an ammonia water spray gun (2) disposed at the bottom of the evaporation tower, wherein the nozzle of the ammonia water spray gun (2) extends into the evaporation tower; and at least one heat exchange layer arranged in the evaporation tower, each of the heat exchange layers being located above the ammonia spray gun (2).

2. The steam heat exchange ammonia evaporator device according to claim 1, characterized in that: The nozzle of the ammonia water spray gun (2) extends into the axis of the evaporation tower, and the bisector of the angle of the spray sprayed from the nozzle passes through the axis of the evaporation tower.

3. The steam heat exchange ammonia evaporator device according to claim 1, characterized in that: The spray angle of the ammonia water spray gun (2) is 55-65°.

4. The steam heat exchange ammonia evaporator device according to claim 1, characterized in that: Each heat exchange layer is a U-shaped heat exchange coil (3), and the inlet and outlet of each U-shaped heat exchange coil (3) are provided with a hand valve (7), and the end is provided with a hydrophobic device.

5. The steam heat exchange ammonia evaporator device according to claim 4, characterized in that: The number of the U-shaped heat exchange coils (3) is at least two layers, arranged in sequence on the upper and lower sides; The horizontal projections of the two adjacent U-shaped heat exchange coils (3) are perpendicular to each other.

6. The steam heat exchange ammonia evaporator device according to claim 4, characterized in that: The height difference between the lowermost U-shaped heat exchange coil (3) and the ammonia spray gun (2) is at least 30 cm.

7. The steam heat exchange ammonia evaporator device according to claim 1, characterized in that: A hand hole (4) is provided above the heat exchange layer.

8. The ammonia evaporator device with steam heat exchange according to any one of claims 1 to 7, characterized in that: A support lug (5) is provided in the middle of the evaporation tower.

9. An SCR denitrification system, characterized in that: An ammonia evaporator device comprising the steam heat exchange according to any one of claims 1 to 8.

10. The SCR denitration system according to claim 9, characterized in that: The mixed gas outlet (6) is connected to the ammonia injection grid; The heat exchange layer is connected to the boiler steam pipe.

Images