A desulfurization and denitrification system using a filler to load sulfite

Abstract

The present application relates to a kind of desulfurization and denitrification system of sulfite ammonium loaded with filler, including filler reaction tower, temperature reducing heat exchanger, water washing tower, low temperature concentration device, impregnation regeneration device and anaerobic drying device, filler reaction tower is equipped with the filler of loading sulfite ammonium crystal inside, the gas outlet of filler reaction tower is connected with the inlet of temperature reducing heat exchanger, the outlet of temperature reducing heat exchanger is connected with the gas inlet of water washing tower, the slurry outlet of water washing tower is connected with the inlet of low temperature concentration device, the outlet of low temperature concentration device is connected with impregnation regeneration device, impregnation regeneration device is used to immerse filler in inside and load sulfite ammonium on surface, first filler conveying device is arranged between impregnation regeneration device and anaerobic drying device.Advantages: can be realized in the absence of catalyst and low temperature condition, the synchronous removal of SO2 And NOx, while using sulfite ammonium material reaction to capture regeneration process, reduce the consumption of sulfite ammonium material, entire processing process does not have the disadvantage of waste water treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flue gas treatment equipment, in particular to a desulfurization and denitrification system using filler loaded sulfite. BACKGROUND

[0002] SO2 and NOx are the main gaseous pollutants in coal-fired places and are one of the main and key pollution indicators controlled by the state. Flue gas desulfurization and denitrification treatment is to purify the flue gas carrying SO2 and NOx pollutants to meet the emission standard requirements.

[0003] At present, there are many types of desulfurization and denitrification processes. The most typical desulfurization process is limestone wet desulfurization process, ammonia wet desulfurization process, etc., and the most common denitrification process is SCR and SNCR process. The former is to use ammonia to react with NOx under the action of a catalyst, and the latter is to spray a reducing agent in a temperature window suitable for denitrification reaction without a catalyst, thereby converting NOx into harmless nitrogen and water.

[0004] The above-mentioned desulfurization and denitrification processes are all mature and applied processes, but they also have some unavoidable shortcomings, such as wastewater treatment problems of wet desulfurization process, the need for a catalyst for SCR, and the need for a higher and suitable reaction temperature for SNCR. At present, the desulfurization and denitrification process using filler loaded sulfite developed by Beijing Qingxin Environmental Technology Co., Ltd. is a dry low-temperature desulfurization and denitrification combined process. Using ammonium sulfite and liquid ammonia (or ammonia water) as raw materials, the desulfurization and denitrification process can be realized simultaneously without the need for a catalyst and at a temperature lower than 110℃. However, since ammonium sulfite decomposes rapidly above 70℃, a large amount of material has already decomposed without participating in the reaction, resulting in high material consumption.

[0005] Therefore, it is necessary to develop a new desulfurization and denitrification technology to solve the above technical problems. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a desulfurization and denitrification system using filler loaded sulfite, which effectively overcomes the defects of the prior art.

[0007] The technical solution of the present application to solve the above technical problems is as follows:

[0008] The application discloses a desulfurization and denitration system loaded with sulfite ammonium, which comprises a filler reaction tower, a temperature reduction heat exchanger, a water washing tower, a low-temperature concentration device, an immersion regeneration device and an anaerobic drying device, the filler reaction tower is internally provided with filler loaded with sulfite ammonium crystals, a gas outlet of the filler reaction tower is connected with an inlet of the temperature reduction heat exchanger, an outlet of the temperature reduction heat exchanger is connected with an air inlet of the water washing tower, a slurry outlet of the water washing tower is connected with an inlet of the low-temperature concentration device, an outlet of the low-temperature concentration device is connected with the immersion regeneration device, the immersion regeneration device is used for immersing the filler in the interior and loading the sulfite ammonium crystals on the surface of the filler, the anaerobic drying device is used for air-drying the filler taken out from the immersion regeneration device, and a first filler conveying device is arranged between the immersion regeneration device and the anaerobic drying device.

[0009] Based on the technical scheme, the application further has the following improvements.

[0010] Further, the temperature reduction heat exchanger is an indirect heat exchanger.

[0011] Further, the low-temperature concentration device is a low-temperature evaporator.

[0012] Further, the immersion regeneration device comprises a box body, a sandwich layer is arranged on the side wall of the box body, heat exchange pipes are arranged in the sandwich layer, the heat exchange pipes are filled with refrigerant, a liquid inlet and a liquid outlet are arranged on the box body, and the liquid inlet is connected with the outlet of the low-temperature concentration device.

[0013] Further, an ammonia gas pipe is arranged on the bottom wall of the box body, and the ammonia gas pipe is connected with an ammonia gas source.

[0014] Further, the anaerobic drying device is an anaerobic drying box.

[0015] Further, the first filler conveying device is a belt conveyor.

[0016] Further, a filler pretreatment device is further arranged, a second filler conveying device is arranged between the filler pretreatment device and the immersion regeneration device, the filler pretreatment device comprises a vibrator and a loading disc, the loading disc is horizontally arranged on the upper end of the vibrator, a screen is horizontally arranged in the loading disc, and a gap is arranged between the screen and the bottom wall of the loading disc.

[0017] Further, the second filler conveying device is a belt conveyor.

[0018] The application has the advantages that the synchronous removal of SO2 and NOx can be realized under the conditions of no catalyst and low temperature, the sulfite ammonium material is captured and regenerated after reaction, the consumption of the sulfite ammonium material is reduced, the cost of the reaction material is greatly reduced, and the whole treatment process has no disadvantages of waste water treatment. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a desulfurization and denitrification system using filler-loaded ammonium sulfite according to the present invention;

[0020] Figure 2 This is a schematic structural diagram of a filler pretreatment device in a desulfurization and denitrification system using fillers loaded with ammonium sulfite according to the present invention.

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

[0022] 1. Packing reaction tower; 2. Cooling heat exchanger; 3. Water washing tower; 4. Low-temperature concentration device; 5. Immersion regeneration device; 6. Anaerobic drying device; 7. Packing pretreatment device; 51. Box; 71. Vibrator; 72. Loading tray; 73. Screen. DETAILED DESCRIPTION

[0023] The principles and features of the present invention are described below with reference to 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] Example: Figure 1 As shown, the desulfurization and denitrification system using filler loaded with ammonium sulfite in this embodiment includes a filler reaction tower 1, a cooling heat exchanger 2, a water scrubber 3, a low-temperature concentration device 4, an immersion regeneration device 5 and an anaerobic drying device 6. The filler reaction tower 1 is filled with filler loaded with ammonium sulfite crystals. The gas outlet of the filler reaction tower 1 is connected to the inlet of the cooling heat exchanger 2, the outlet of the cooling heat exchanger 2 is connected to the air inlet of the water scrubber 3, the slurry outlet of the water scrubber 3 is connected to the inlet of the low-temperature concentration device 4, and the outlet of the low-temperature concentration device 4 is connected to the immersion regeneration device 5. The immersion regeneration device 5 is used to immerse the filler inside and load ammonium sulfite on the surface of the filler. The anaerobic drying device 6 is used to air-dry the filler after being taken out of the immersion regeneration device 5. A first filler conveying device is provided between the immersion regeneration device 5 and the anaerobic drying device 6.

[0025] The usage process is as follows:

[0026] During use, the flue gas carrying SO2 and NOx, after entering the packed reaction tower 1, reacts with the ammonium sulfite loaded on the packing in the packed reaction tower 1 to generate ammonium bisulfite and ammonium sulfate. The reaction equation is as follows:

[0027] 4(NH4)2SO3+2NO2=4(NH4)2SO4+N2

[0028] 2(NH4)2SO3+2NO=(NH4)2SO4+N2

[0029] (NH4)2SO3+SO2+H2O=2(NH4)HSO3

[0030] At the same time, ammonium sulfite is obviously decomposed at a temperature above 70°C:

[0031] (NH4)2SO3.H2O = 2NH3 + SO2 + H2O

[0032] As can be seen from the above equation, SO2 and NOx can be removed by reacting with ammonium sulfite in the packed tower 1. The defect of the reaction is that the unreacted ammonium sulfite material is easily decomposed by heat, mixed with NH3 and SO2 in the flue gas, and then gradually reduced to below 70°C in the temperature reducing heat exchanger 2. NH3 and SO2 quickly react to generate tiny particles of ammonium sulfite, which is finally captured in the slurry of the water washing tower 3. Thus, the flue gas is purified by desulfurization and denitrification, and the entrained ammonium sulfite component is also recovered. On the other hand, after the water washing tower 3 captures the ammonium sulfite particles, part of the slurry is introduced into the subsequent low-temperature concentration device 4, while a part of the clean process water is supplemented. The slurry concentration process is realized in the low-temperature concentration device 4. Then the concentrated liquid is output to the immersion regeneration device 5. At the same time, the packed tower 1 in which the reaction is complete has lost the function of desulfurization and denitrification. The part of the packing is taken out from the packed tower 1, and the invalid reaction product (ammonium sulfate) loaded on the surface is removed from the packing. Subsequently, it is placed in the immersion regeneration device 5, where the packing is fully contacted with the concentrated liquid from the low-temperature concentration device 4, and the ammonium sulfite in the concentrated liquid is attached to (i.e., loaded on) the surface of the packing. The wet packing loaded with the concentrated liquid is placed in the subsequent anaerobic drying device 6, and the wet packing is gradually dried and crystallized into a solid, and the packing is completely regenerated and can be replenished to the packed tower 1 for reaction. The whole system is designed reasonably, which can realize the simultaneous removal of SO2 and NOx under the conditions of no catalyst and low temperature, and the use of the ammonium sulfite material reaction and capture regeneration process reduces the consumption of ammonium sulfite material, greatly reduces the cost of the reaction material, and the whole process does not have the disadvantages of waste water treatment.

[0033] The desulfurization and denitrification system of the present embodiment using packing to load ammonium sulfite can be applied to boiler flue gas or other places where coal-fired flue gas exists.

[0034] As can be seen from the above equation, SO2 and NOx can be removed by reacting with ammonium sulfite in the packed tower 1. However, the defect of the reaction is that the unreacted ammonium sulfite material is easily decomposed by heat, mixed with NH3 and SO2 in the flue gas, and thus the temperature in the packed tower 1 is generally controlled below 100°C during actual operation to reduce the invalid loss of the material, while ensuring that the temperature is above 60°C to make the reaction temperature in the tower reach the temperature window required for ammonium sulfite denitrification.

[0035] In the embodiment, the above-mentioned cooling heat exchanger 2 is an indirect heat exchanger. The refrigerant is in the tube side of the cooling heat exchanger 2, and the flue gas is in the shell side of the cooling heat exchanger 2.

[0036] In the embodiment, the above-mentioned low-temperature concentration device 4 is a low-temperature evaporator. The vacuum degree of the low-temperature evaporator should be above 75 KPa, so that the ammonium sulfite-rich slurry from the water washing tower 3 can be boiled and evaporated below 70℃, realizing the ammonium sulfite slurry concentration process.

[0037] As a preferred embodiment, the above-mentioned immersion regeneration device 5 comprises a box 51, the side wall of the box 51 is provided with a sandwich layer, the sandwich layer is provided with heat exchange pipes, the heat exchange pipes are provided with refrigerant, the box 51 is provided with a liquid inlet and a liquid outlet, and the liquid inlet is connected to the outlet of the low-temperature concentration device 4.

[0038] In the above-mentioned embodiment, the concentrated liquid from the low-temperature concentration device 4 enters the box 51, the side wall of the box 51 is cooled by circulating the refrigerant, so that the ammonium sulfite-rich slurry in the box 51 is loaded on the surface of the filler in a low-temperature environment,

[0039] As a preferred embodiment, the bottom wall of the box 51 is provided with an ammonia gas pipe, and the ammonia gas pipe is connected to an ammonia gas source.

[0040] In the above-mentioned embodiment, since bisulfite may exist in the concentrated liquid from the low-temperature concentration device 4, ammonia gas is introduced into the box 51 to fully regenerate the bisulfite in the concentrated liquid into ammonium sulfite. The amount of ammonia gas to be introduced needs to be calculated according to the SO2 concentration and removal amount in the flue gas, or analyzed and tested by collecting the concentrated liquid in the immersion unit, detecting the content of bisulfite ions, and the molar ratio of ammonia gas to bisulfite ions needs to be at least 1:1.

[0041] In the embodiment, the above-mentioned oxygen-free drying device 6 adopts an existing oxygen-free drying box, and the specific model can be flexibly and reasonably adapted according to actual use requirements, which will not be described here. In the oxygen-free drying device 6, the filler with concentrated liquid attached is evaporated and crystallized in the device, so that the material is attached to the filler in a solid state. It needs to be observed that the state of the crystalline material, and only about 10% of water needs to be attached. It needs to ensure the attachment state of the crystalline material on the filler, and it cannot be dried too much to cause the crystalline material to separate from the filler, and it does not need to remove the crystallization water attached to the ammonium sulfite. In addition, the air-drying temperature cannot be too high, and it is best to keep it below 60℃.

[0042] In this embodiment, the first filler conveying device is a belt conveyor. The concentrate-loaded filler is removed from the impregnation regeneration device 5 and placed on the first filler conveying device. The filler is then transported to the anaerobic drying device 6. Manual placement of the filler into the anaerobic drying device 6 eliminates manual handling, saving time and effort.

[0043] As a preferred embodiment, Figure 2 As shown, it also includes a filler pretreatment device 7, a second filler conveying device is provided between the filler pretreatment device 7 and the impregnation regeneration device 5, the filler pretreatment device 7 includes a vibrator 71 and a loading tray 72, the loading tray 72 is horizontally installed at the upper end of the vibrator 71, a screen 73 is horizontally installed in the loading tray 72, and a gap is provided between the screen 73 and the bottom wall of the loading tray 72.

[0044] In the above embodiment, the ineffective filler in the packing reaction tower 1 is removed after use and placed on the screen 73. The vibrator 71 is turned on to vibrate the loading tray 72 and the screen 73, thereby "vibrating off" the ineffective particulate matter (ineffective reaction product ammonium sulfate) loaded on the filler. The filler is then placed in the impregnation regeneration device 5 to be reloaded with the ammonium sulfite-rich slurry. The filler pretreatment device 7 is simple in design and relatively easy to operate.

[0045] Of course, the material particles on the filler can also be treated by using a high-pressure air flow blowing device or method.

[0046] In this embodiment, the second filler conveying device is a belt conveyor. After the filler is removed from the filler reaction tower 1 and pre-treated, it is transferred to the second filler conveying device and then transported to the impregnation regeneration device 5. The filler is manually placed into the impregnation regeneration device 5, eliminating manual handling and saving time and effort.

[0047] 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 to 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, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0048] In addition, the terms "first", "second", etc. are used only for the purpose of description and do not imply or imply relative importance or imply the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0049] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0051] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" 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 present application. In the present application, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or features of different embodiments or examples described in the present application without contradiction.

[0052] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A desulfurization and denitrification system using filler-loaded ammonium sulfite, characterized in that: The invention comprises a packing reaction tower (1), a cooling heat exchanger (2), a water washing tower (3), a low-temperature concentration device (4), an immersion regeneration device (5) and an oxygen-free drying device (6). The packing reaction tower (1) is provided with a packing loaded with ammonium sulfite crystals. The gas outlet of the packing reaction tower (1) is connected to the inlet of the cooling heat exchanger (2), the outlet of the cooling heat exchanger (2) is connected to the air inlet of the water washing tower (3), the slurry outlet of the water washing tower (3) is connected to the inlet of the low-temperature concentration device (4), the outlet of the low-temperature concentration device (4) is connected to the immersion regeneration device (5), the immersion regeneration device (5) is used to immerse the packing inside and load ammonium sulfite on the surface of the packing, the oxygen-free drying device (6) is used to air-dry the packing after being taken out of the immersion regeneration device (5), and a first packing conveying device is provided between the immersion regeneration device (5) and the oxygen-free drying device (6).

2. The desulfurization and denitrification system using filler-loaded ammonium sulfite according to claim 1, characterized in that: The cooling heat exchanger (2) is an indirect heat exchanger.

3. The desulfurization and denitrification system using filler-loaded ammonium sulfite according to claim 1, characterized in that: The low-temperature concentration device (4) is a low-temperature evaporator.

4. The desulfurization and denitrification system using filler-loaded ammonium sulfite according to claim 1, characterized in that: The impregnation regeneration device (5) comprises a box body (51), a side wall of the box body (51) is provided with an interlayer, a heat exchange tube is provided in the interlayer, a refrigerant flows through the heat exchange tube, and a liquid inlet and a liquid outlet are provided on the box body (51), and the liquid inlet is connected to the outlet of the low-temperature concentration device (4).

5. The desulfurization and denitrification system using filler-loaded ammonium sulfite according to claim 4, characterized in that: An ammonia pipe is provided on the bottom wall of the box body (51), and the ammonia pipe is connected to an ammonia source.

6. The desulfurization and denitrification system using filler-loaded ammonium sulfite according to claim 1, characterized in that: The oxygen-free drying device (6) is an oxygen-free drying box.

7. The desulfurization and denitrification system using filler-loaded ammonium sulfite according to claim 1, characterized in that: The first filler conveying device is a belt conveyor.

8. A desulfurization and denitrification system using filler-loaded ammonium sulfite according to any one of claims 1 to 7, characterized in that: The invention also includes a filler pretreatment device (7), wherein a second filler conveying device is provided between the filler pretreatment device (7) and the impregnation regeneration device (5), and the filler pretreatment device (7) includes a vibrator (71) and a loading tray (72), wherein the loading tray (72) is horizontally installed at the upper end of the vibrator (71), and a screen (73) is horizontally installed in the loading tray (72), and a gap is provided between the screen (73) and the bottom wall of the loading tray (72).

9. The desulfurization and denitrification system using filler-loaded ammonium sulfite according to claim 8, characterized in that: The second filler conveying device is a belt conveyor.

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