Ammonia distillation tower for supplying ammonia gas for purification and denitration treatment of waste incineration flue gas

Abstract

The utility model relates to an ammonia still for supplying ammonia gas for purifying and denitrifying waste incineration flue gas. The problems that an existing ammonia still is complex in structure, low in ammonia production efficiency and large in energy consumption are solved. The device comprises a reboiler used for heating entering ammonia water to form ammonia gas; a heat exchange pipe for circulating ammonia water is arranged in the reboiler; the condenser is used for removing water vapor in the ammonia gas; the ammonia gas outlet is formed in the top of the shell; the ammonia distillation layer is arranged between the reboiler and the condenser; the ammonia distillation layer comprises a tower plate and a downcomer; ammonia gas generated in the reboiler enters the ammonia distillation layer, so that the ammonia gas is separated from water, and the purified ammonia gas is discharged from the ammonia gas outlet through the condenser. The reboiler, the ammonia distillation layer and the condenser form an integrated combined structure, pipeline connection is reduced, the structure is greatly simplified, ammonia gas is discharged through the ammonia distillation layer, the ammonia gas generation efficiency is improved, energy consumption is low, and the device is suitable for rapid production of a garbage power plant with small gas consumption.

Description

Technical Field

[0001] The utility model relates to ammonia preparation applied to a flue gas denitration system in the garbage incineration industry, in particular to an ammonia still for purifying and denitrifying the flue gas of garbage incineration and supplying ammonia. Background Art

[0002] Centralized incineration has gradually become the main method for treating domestic waste in my country. A certain amount of nitrogen oxides - NOx will be produced in the flue gas of the waste incinerator. The currently widely used flue gas denitrification treatment technologies are selective catalytic reduction - SCR and selective non-catalytic reduction - SNCR.

[0003] SCR denitrification technology refers to a clean denitrification technology that uses liquid ammonia or ammonia water containing amino groups (NH3) as a reducing agent to selectively reduce nitrogen oxides in flue gas under the action of a certain temperature and catalyst, and generate non-toxic and non-polluting N2 and water.

[0004] Ammonia distillation towers are used to provide ammonia for the denitrification reaction. Liquid ammonia or aqueous ammonia is evaporated into ammonia gas within the tower and then fed into the denitrification system. Currently, most ammonia distillation towers utilize direct contact heat exchange with water vapor. Ammonia water enters the tower and directly exchanges heat with water vapor to produce a mixed steam containing ammonia. This mixed steam passes through a top splitter, condensing most of the water vapor to produce high-purity ammonia gas and condensed water. The ammonia gas is discharged through the tower's top exhaust port, while the condensed water enters the bottom wastewater stream. This steam condensed water cannot be recycled, increasing the amount of wastewater at the bottom. This wastewater must be cooled to a certain temperature before exiting the system, increasing cooling water consumption in the wastewater cooler and causing significant energy waste. Indirect ammonia distillation processes include thermal oil distillation, tubular furnace heating, and steam heating. These three processes share a fundamental principle: using thermal oil, tubular furnaces, and steam to indirectly heat the ammonia water at the bottom of the tower. The heated ammonia gas then overflows from the water and is discharged from the top of the tower. The steam-heated distillation process offers the lowest operating costs and initial investment.

[0005] To meet the required temperature, existing ammonia stills require preheating of the ammonia solution before it enters the tower. This often involves numerous heaters and circulation pumps, resulting in complex structures and increased production costs. Direct heating is also commonly used, leading to the direct discharge of steam condensate into the ammonia still wastewater system. This wastes steam condensate, requires purification, and increases environmental pressure. Furthermore, existing ammonia stills require high production volumes, resulting in high production costs and often energy waste. Utility Model Content

[0006] In order to solve the problems of complex structure, low ammonia production efficiency and high energy consumption of existing ammonia evaporation towers in the background technology, the utility model provides an ammonia evaporation tower for ammonia supply for purifying and denitrifying waste incineration flue gas.

[0007] The technical solution of the utility model is: an ammonia still tower for purifying and denitrifying waste incineration flue gas to supply ammonia, comprising a shell and:

[0008] A reboiler is provided in the bottom area of ​​the shell and is used to heat the incoming ammonia water to form ammonia gas; the reboiler is provided with a heat exchange tube for the circulation of the ammonia water;

[0009] A condenser is provided in the top area of ​​the shell and is used to remove water vapor from the ammonia gas;

[0010] An ammonia outlet is provided at the top of the shell;

[0011] The ammonia distillation layer is provided between the reboiler and the condenser; the ammonia distillation layer includes a tower plate and a downcomer; the shell is provided with an inlet for concentrated ammonia solution, and the concentrated ammonia solution entering the inlet forms a liquid pool on the tower plate; the ammonia gas generated in the reboiler enters the ammonia distillation layer so that the ammonia gas is separated from the water, the purified ammonia gas is discharged from the ammonia outlet through the condenser.

[0012] As a further improvement of the present invention, the ammonia distillation layer has multiple layers, each of which includes the tower plate and the downcomer; the downcomers of two adjacent ammonia distillation layers are staggered.

[0013] As a further improvement of the present invention, there are multiple concentrated ammonia solution inlets, and the multiple concentrated ammonia solution inlets are arranged in different ammonia distillation layers for balancing the ammonia production and purity.

[0014] As a further improvement of the present invention, different ammonia distillation layers are arranged linearly; when the liquid level of the liquid pool of the upper ammonia distillation layer is higher than the end of the downcomer, the concentrated ammonia water of this layer falls from the downcomer onto the tower plate of the lower ammonia distillation layer; when the liquid level of the liquid pool of the lowest ammonia distillation layer is higher than the end of the downcomer, the concentrated ammonia water of this layer falls from the downcomer into the reboiler.

[0015] As a further improvement of the present invention, the downcomer includes a downcomer plate and an arc-shaped plate; the downcomer plate is arranged on one side close to the tower plate, and the upper surface of the downcomer plate is provided with a wave shape that bends back and forth.

[0016] As a further improvement of the present invention, the downcomer and the tower plate are separated by the downcomer plate, and the area ratio of the downcomer to the pedal is 1 / 6-1 / 5.

[0017] As a further improvement of the present invention, there are multiple heat exchange tubes, and three heat exchange tubes that are not on the same straight line are arranged in an equilateral triangle, and the ammonia water moves from bottom to top in the heat exchange tubes.

[0018] As a further improvement of the present invention, the following further features are also included:

[0019] The high-temperature steam inlet is provided in the bottom area of ​​the shell and is used for the entry of high-temperature steam to heat the ammonia water in the reboiler and generate ammonia gas;

[0020] The condensed water outlet is arranged at the bottom area of ​​the shell and is used for discharging condensed water; the high-temperature steam inlet is arranged above the condensed water outlet.

[0021] As a further improvement of the present invention, it also includes a circulating liquid discharge port, which is arranged at the bottom of the shell and below the reboiler.

[0022] As a further improvement of the present invention, it also includes a cooling water inlet and a cooling water outlet. The cooling water inlet and the cooling water outlet cooperate with each other to remove water vapor from the ammonia in the condenser, and the cooling water outlet is arranged above the cooling water inlet.

[0023] The beneficial effect of the utility model is that a reboiler, an ammonia evaporation layer and a condenser are arranged in the shell to form an integrated combination structure, which reduces pipeline connections and greatly simplifies the structure. Ammonia water is heated by the reboiler to form ammonia gas, and then the ammonia gas is discharged through the ammonia evaporation layer, thereby improving the ammonia production efficiency, reducing energy consumption, and being suitable for rapid production with a small gas consumption in garbage power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Attachment Figure 1 It is a structural schematic diagram of an embodiment of the present utility model.

[0025] Attachment Figure 2 It is a schematic cross-sectional view of an embodiment of the present utility model.

[0026] Attachment Figure 3 This is a schematic structural diagram of a reboiler according to an embodiment of the present utility model.

[0027] Attachment Figure 4 This is a schematic structural diagram of a condenser according to an embodiment of the present utility model.

[0028] Attachment Figure 5 This is a schematic diagram of the structure of the multi-layer ammonia evaporation layer when combined in an embodiment of the present utility model.

[0029] Attachment Figure 6 This is a schematic structural diagram of a single-layer ammonia evaporation layer in an embodiment of the present utility model.

[0030] Attachment Figure 7 For attachment Figure 6 Schematic diagram of the structure in another direction.

[0031] In the figure, 1. Shell; 11. Ammonia outlet; 12. Concentrated ammonia solution inlet; 13. High-temperature steam inlet; 14. Condensate outlet; 15. Circulating liquid outlet; 16. Cooling water inlet; 17. Cooling water outlet; 2. Reboiler; 21. Heat exchange tube; 3. Condenser; 4. Ammonia evaporation layer; 41. Tower plate; 42. Downcomer; 421. Downcomer plate; 422. Curved plate. DETAILED DESCRIPTION

[0032] The following is a further description of the embodiments of the present invention in conjunction with the accompanying drawings:

[0033] Depend on Figure 1 Combine Figure 2-7 As shown, an ammonia still for purifying and denitrifying waste incineration flue gas and supplying ammonia comprises a shell 1 and further comprises:

[0034] The reboiler 2 is provided at the bottom area of ​​the shell 1 and is used to heat the incoming ammonia water to form ammonia gas; the reboiler 2 is provided with a heat exchange tube 21 for the circulation of the ammonia water;

[0035] The condenser 3 is provided in the top area of ​​the shell 1 and is used to remove water vapor from the ammonia gas;

[0036] An ammonia outlet 11 is provided at the top of the housing 1;

[0037] The ammonia still layer 4 is located between the reboiler 2 and the condenser 3. The ammonia still layer 4 includes a tray 41 and a downcomer 42. The housing 1 is provided with a concentrated ammonia solution inlet 12. The concentrated ammonia solution introduced by the concentrated ammonia solution inlet 12 forms a pool on the tray 41. Ammonia gas generated in the reboiler 2 enters the ammonia still layer 4, where it is separated from water and purified. The ammonia gas is then discharged from the condenser 3 through an ammonia outlet 11. The advantageous effect of the present invention is that the reboiler, ammonia still layer, and condenser are arranged within the housing, forming an integrated structure, which reduces piping connections and greatly simplifies the structure. Ammonia gas is generated by heating ammonia water in the reboiler and then discharged through the ammonia still layer. This improves ammonia production efficiency, reduces energy consumption, and is suitable for rapid production of small gas volumes in waste-to-energy plants. Specifically, the reboiler and condenser are each equipped with a thermometer interface, a pressure gauge interface, and a liquid level gauge interface. This allows for the installation of thermometers, pressure gauges, or liquid level gauges as needed, facilitating accurate monitoring of conditions within the ammonia still column, enabling precise control and reducing energy consumption. To further explain the product structure, concentrated ammonia solution enters the ammonia still layer of the ammonia still tower from the side of the concentrated ammonia solution inlet, forming a liquid pool on the tower trays. This pool undergoes heat exchange with the ammonia gas rising from the bottom of the tower, separating the ammonia gas. When the liquid level in the pool on the upper tower tray exceeds the downcomer, the concentrated ammonia solution falls from the downcomer onto the lower tower trays, thereby achieving concentrated ammonia classification and ultimately falling into the reboiler at the bottom of the tower. Within the reboiler's heat exchange tubes, high-temperature steam enters the reboiler shell through the warm steam inlet, indirectly heating the ammonia solution through the heat exchange tubes. The ammonia gas generated within the heat exchange tubes rises step by step along the tower trays within the ammonia still tower. After separation and removal of the contained water vapor in the condenser at the top of the tower, it is discharged from the tower. Although the trays are equipped with holes for steam passage, in actual use, the high-pressure ammonia gas below continues to rise, so the concentrated ammonia solution does not fall directly from the holes on the upper trays to the lower trays. After adjustment and metering, it goes to the flue gas purification and denitrification treatment system; the clean condensate produced by the high-temperature steam in the reboiler is discharged from the steam condensate outlet; when the dilute ammonia water level in the reboiler exceeds the set value, the valve at the circulating liquid drain port at the bottom of the reboiler will be automatically opened for drainage. At this time, the ammonia water in the reboiler evaporates after multiple cycles, and high-temperature dilute ammonia water with a concentration of less than 5% is discharged. The high-temperature dilute ammonia water is heated by the concentrated ammonia water preheater to heat the concentrated ammonia water solution, so that the low-temperature concentrated ammonia water is heated before entering the ammonia evaporation tower, while the temperature of the high-temperature dilute ammonia water is reduced, realizing heat recovery and utilization; it is then cooled by the dilute ammonia water cooler and stored in the ammonia water storage tank for use by the SNCR system. This ammonia evaporation system uses water vapor to indirectly heat ammonia gas, and the obtained ammonia evaporation wastewater is dilute ammonia water with a concentration of less than 5%, which can be used by the SNCR system, achieving secondary utilization of ammonia water and reducing production costs and environmental protection costs.The high-temperature dilute ammonia solution after ammonia evaporation is used to exchange heat with the concentrated ammonia solution. There is no need to set up a heater to heat the concentrated ammonia solution, and its temperature also meets the temperature required for entering the ammonia evaporation tower; the high-temperature dilute ammonia solution is cooled once here, and the demand for cooling water is reduced when the cooler performs secondary cooling, thereby achieving full energy utilization and reducing water resource waste.

[0038] The ammonia distillation layer 4 has multiple layers, each of which includes the trays 41 and the downcomers 42. The downcomers 42 of two adjacent ammonia distillation layers 4 are staggered. This facilitates the fall of concentrated ammonia solution in the upper liquid pool into the adjacent lower mother liquor layer, facilitating control and enabling separation and purification of ammonia gas and water.

[0039] There are multiple concentrated ammonia solution inlets 12, each of which is located in different ammonia distillation layers 4 to balance ammonia production and purity. Specifically, there are three concentrated ammonia solution inlets, which facilitate balance between ammonia production and purity, facilitate precise control by the user, and reduce energy consumption.

[0040] The different ammonia distillation layers 4 are arranged linearly. When the liquid level of the upper ammonia distillation layer 4 pool exceeds the end of the downcomer 42, the concentrated ammonia solution in this pool falls from the downcomer 42 onto the tray 41 of the lower ammonia distillation layer 4. When the liquid level of the lowest ammonia distillation layer 4 pool exceeds the end of the downcomer 42, the concentrated ammonia solution in this pool falls from the downcomer 42 into the reboiler 2. This facilitates the fall of the concentrated ammonia solution in the upper pool into the adjacent lower mother liquor layer, facilitating control and enabling the separation and purification of ammonia gas and water.

[0041] The downcomer 42 comprises a downcomer plate 421 and a curved plate 422. The downcomer plate 421 is positioned near the side of the tray 41, and its upper surface features a wavy, undulating pattern. Specifically, the downcomer plate 421 separates the downcomer 42 from the tray 41, and the area ratio of the downcomer 42 to the tread plate is 1 / 6-1 / 5. This creates a larger liquid pool, facilitating heat exchange between ammonia gas and concentrated aqueous ammonia, separating the ammonia gas and facilitating ammonia separation and purification.

[0042] There are multiple heat exchange tubes 21, and three heat exchange tubes 21 that are not on the same straight line are arranged in an equilateral triangle, and the ammonia water moves from bottom to top in the heat exchange tubes 21. In this way, the reboiler has high heat exchange efficiency, saves energy consumption, and reduces costs.

[0043] The utility model also includes:

[0044] A high-temperature steam inlet 13 is provided at the bottom area of ​​the shell 1 for the entry of high-temperature steam to heat the ammonia water in the reboiler 2 and generate ammonia gas;

[0045] The condensate outlet 14 is provided at the bottom area of ​​the shell 1 for discharging the condensate; the high-temperature steam inlet 13 is provided above the condensate outlet 14. This facilitates heating the reboiler and generating ammonia, while also enabling heat reuse and reducing energy consumption.

[0046] The present invention further includes a circulating liquid discharge port 15, which is provided at the bottom of the shell 1 and below the reboiler 2. When the liquid level of the ammonia solution (dilute ammonia solution with a low concentration) in the reboiler exceeds a set value, the valve at the circulating liquid discharge port at the bottom of the reboiler is automatically opened to discharge the liquid. At this time, the ammonia solution in the reboiler evaporates after multiple cycles, and high-temperature dilute ammonia solution with a concentration of less than 5% is discharged.

[0047] The present invention further includes a cooling water inlet 16 and a cooling water outlet 17, which cooperate with each other to remove water vapor from the ammonia gas in the condenser. The cooling water outlet 17 is located above the cooling water inlet 16. This facilitates the re-condensation of water vapor in the discharged ammonia gas, further purifying the ammonia gas.

[0048] In the description of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "installed", "connected", and "connected" 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, or it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0050] Technical personnel please note: Although the utility model has been described according to the above specific implementation methods, the utility model concept is not limited to this utility model. Any modification using the utility model concept will be included in the scope of protection of the utility model patent right.

Claims

1. An ammonia evaporation tower for purifying and denitrifying waste incineration flue gas and supplying ammonia, comprising a shell (1), characterized in that Also includes: A reboiler (2) is provided in the bottom area of ​​the shell (1) and is used to heat the incoming ammonia water to form ammonia gas; a heat exchange tube (21) for circulating the ammonia water is provided in the reboiler (2); A condenser (3) is provided in the top area of ​​the shell (1); and is used to remove water vapor from the ammonia gas; an ammonia outlet (11) provided at the top of the housing (1); An ammonia evaporation layer (4) is provided between the reboiler (2) and the condenser (3); the ammonia evaporation layer (4) comprises a tower plate (41) and a downcomer (42); a concentrated ammonia solution inlet (12) is provided on the shell (1), and the concentrated ammonia solution entering through the concentrated ammonia solution inlet (12) forms a liquid pool on the tower plate (41); ammonia gas generated in the reboiler (2) enters the ammonia evaporation layer (4), so that the ammonia gas is separated from water, the purified ammonia gas is discharged from the ammonia outlet (11) through the condenser (3).

2. The ammonia still for waste incineration flue gas purification and denitrification treatment of ammonia supply according to claim 1, characterized in that The ammonia evaporation layer (4) has multiple layers, and each ammonia evaporation layer (4) includes the tower plate (41) and the downcomer (42); the downcomers (42) of two adjacent ammonia evaporation layers (4) are staggered.

3. The ammonia still for waste incineration flue gas purification and denitrification treatment of ammonia supply according to claim 2, characterized in that There are multiple concentrated ammonia solution inlets (12), and the multiple concentrated ammonia solution inlets (12) are arranged in different ammonia distillation layers (4) for balancing the ammonia production and purity.

4. The ammonia still for purifying and denitrifying waste incineration flue gas according to claim 3 is characterized in that Different ammonia distillation layers (4) are arranged in a linear manner; when the liquid level of the liquid pool of the upper ammonia distillation layer (4) is higher than the end of the downcomer (42), the concentrated ammonia water of this layer falls from the downcomer (42) onto the tower plate (41) of the lower ammonia distillation layer (4); when the liquid level of the liquid pool of the lowest ammonia distillation layer (4) is higher than the end of the downcomer (42), the concentrated ammonia water of this layer falls from the downcomer (42) into the reboiler (2).

5. The ammonia still for purifying and denitrifying waste incineration flue gas according to claim 1 is characterized in that The downcomer (42) comprises a downcomer plate (421) and an arc-shaped plate (422); the downcomer plate (421) is arranged on one side close to the tower plate (41), and the upper surface of the downcomer plate (421) is provided with a wave shape that bends back and forth.

6. The ammonia still for purifying and denitrifying waste incineration flue gas according to claim 5, characterized in that The downcomer (421) separates the downcomer (42) and the tower plate (41), and the area ratio of the downcomer (42) to the pedal is 1 / 6-1 / 5.

7. The ammonia still for purifying and denitrifying waste incineration flue gas according to claim 1, characterized in that There are multiple heat exchange tubes (21), and three heat exchange tubes (21) that are not on the same straight line are arranged in a regular triangle. Ammonia water moves from bottom to top in the heat exchange tubes (21).

8. The ammonia still for purifying and denitrifying waste incineration flue gas according to claim 1, characterized in that Also includes: A high-temperature steam inlet (13) is provided in the bottom area of ​​the shell (1) for allowing high-temperature steam to enter and heat the ammonia water in the reboiler (2) to generate ammonia gas; The condensed water outlet (14) is provided in the bottom area of ​​the shell (1) and is used for discharging condensed water; the high-temperature steam inlet (13) is provided above the condensed water outlet (14).

9. The ammonia still for purifying and denitrifying waste incineration flue gas according to claim 1, characterized in that It also includes a circulating liquid discharge port (15) which is arranged at the bottom of the shell (1) and below the reboiler (2).

10. The ammonia still for purifying and denitrifying waste incineration flue gas according to claim 1, characterized in that The condenser further comprises a cooling water inlet (16) and a cooling water outlet (17). The cooling water inlet (16) and the cooling water outlet (17) cooperate with each other to remove water vapor from the ammonia gas in the condenser. The cooling water outlet (17) is arranged above the cooling water inlet (16).

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