Efficient low-temperature SCR denitration system

Abstract

The utility model discloses a high-efficiency low-temperature SCR (Selective Catalytic Reduction) denitration system which comprises an ammonia water system which comprises an ammonia preparation device, an ammonia water buffer tank and an ammonia water conveying pump pry which are communicated in sequence; the evaporation injection system comprises an ammonia water evaporator, an ammonia-air mixer, a dilution fan and an ammonia injector, the ammonia water evaporator is communicated with the ammonia water conveying pump skid, and the ammonia water evaporator, the ammonia-air mixer and the ammonia injector are sequentially communicated; the combustion system comprises a combustion chamber and a combustor, the combustor is located in the combustion chamber, and the combustion chamber communicates with an incinerator flue gas pipeline and is connected into the ammonia ejector; the SCR reactor is internally provided with a low-temperature catalyst, an inlet of the SCR reactor is communicated with the ammonia ejector, and the dilution fan is communicated with the ammonia-air mixer and an outlet of the SCR reactor; according to the efficient low-temperature SCR denitration system, the temperature of flue gas entering the SCR reactor is properly increased, meanwhile, denitration can be completed by the efficient low-temperature catalyst only at a low temperature, NOx emission reaches the standard, the natural gas consumption is low, and the cost is low.

Description

Technical Field

[0001] The utility model relates to the technical field of denitration systems, and more specifically to a high-efficiency low-temperature SCR denitration system. Background Art

[0002] Nitrogen oxides are one of the main factors of current air pollution. In non-electric industries such as steel sintering and pelletizing, coking, and lime kilns, due to the low flue gas temperature, in order to reduce the energy consumption required for heating and heating, many projects use low-temperature SCR denitrification after desulfurization and dust removal. The temperature after denitrification reaction is only 180-220°C. At this time, if the flue gas is directly extracted for ammonia evaporation, due to the low flue gas temperature, a large amount of hot air is required, the power consumption of the dilution fan is high, and evaporation is difficult. At this time, an electric heater needs to be set to heat the dilution air to above 260°C, and the required energy consumption is very high. If the high-temperature flue gas in the heating furnace is directly used for heating and heating to directly evaporate ammonia, the high-temperature flue gas can be as high as 900°C or even above 1000°C. Ammonia will have side reactions at such high temperatures, increasing the consumption of ammonia. If the high-temperature flue gas is reduced by mixing with ambient air to control the temperature, an external hot air furnace must be used, which will increase the heating energy consumption and is not energy-saving enough. Therefore, it is necessary to design and develop an efficient, low-temperature, and energy-saving SCR denitrification system.

[0003] In this technology, when the flue temperature at the incinerator outlet is low, the flue gas moisture content is high, and the catalyst reaction temperature is not met, a combustion control system is added to appropriately increase the flue gas temperature entering the SCR reactor so that the temperature inside the SCR reactor reaches the reaction conditions. At the same time, the high-efficiency low-temperature catalyst used only needs a relatively low temperature (150°C) to complete denitrification, so that NOx emissions meet the standards, natural gas consumption is low, and costs are low. Utility Model Content

[0004] In view of the shortcomings of the prior art, the utility model provides a high-efficiency low-temperature SCR denitrification system. The high-efficiency low-temperature SCR denitrification system appropriately increases the temperature of the flue gas entering the SCR reactor by adding a combustion system, so that the temperature inside the SCR reactor reaches the reaction conditions. At the same time, the high-efficiency low-temperature catalyst used only needs a relatively low temperature (150°C) to complete denitrification, so that NOx emissions meet the standards, natural gas consumption is low, and cost is low.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A high-efficiency low-temperature SCR denitrification system, comprising:

[0007] An ammonia system, comprising an ammonia production device, an ammonia buffer tank and an ammonia delivery pump skid, wherein the ammonia production device, the ammonia buffer tank and the ammonia delivery pump skid are connected in sequence;

[0008] An evaporation injection system, comprising an ammonia evaporator, an ammonia-air mixer, a dilution fan and an ammonia injector, wherein the ammonia evaporator is connected to an ammonia delivery pump skid and a metering module is arranged therebetween, and the ammonia evaporator, the ammonia-air mixer and the ammonia injector are connected in sequence;

[0009] A combustion system, comprising a combustion chamber and a burner, wherein the burner is located in the combustion chamber, and the combustion chamber is connected to a flue gas duct of an incinerator and is connected to an ammonia injector;

[0010] The SCR reactor is provided with a low-temperature catalyst inside, and the low-temperature catalyst is installed in layers in the SCR reactor. The inlet of the SCR reactor is connected to the ammonia injector, and the dilution fan is respectively connected to the ammonia-air mixer and the outlet of the SCR reactor.

[0011] The ammonia water system further includes a tail gas absorption tank, and the tail gas absorption tank is cyclically connected to the ammonia water buffer tank.

[0012] Furthermore, the ammonia water delivery pump skid is in circulation communication with the ammonia water buffer tank.

[0013] Furthermore, the ammonia buffer tank, the ammonia delivery pump skid, and the ammonia evaporator are cyclically connected in sequence.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] When the boiler flue temperature is low and does not meet the conventional catalyst reaction temperature, the utility model arranges an ammonia system, an evaporation injection system, a combustion system, and an SCR reactor. By arranging the combustion system and using a low-temperature SCR catalyst, ammonia from the ammonia system is transported to the ammonia evaporator. When the evaporation injection system sprays ammonia, the flue gas is first heated by the combustion system and then passes through the ammonia injector. The ammonia injector uniformly sprays high-temperature flue gas and ammonia into the SCR reactor. The high-efficiency low-temperature catalyst in the SCR reactor only needs a relatively low temperature (150°C) to complete denitrification, so that NOx emissions meet the standards, which greatly reduces the natural gas consumption, thereby reducing the denitrification cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0017] Figure 1 This is a schematic diagram of the structure of a high-efficiency low-temperature SCR denitrification system.

[0018] The following are marked in the figure: 1. Ammonia production device; 2. Ammonia buffer tank; 3. Ammonia delivery pump skid; 4. Tail gas absorption tank; 5. Ammonia evaporator; 6. Ammonia-air mixer; 7. Ammonia injector; 8. SCR reactor; 9. Low-temperature catalyst; 10. Dilution fan; 11. Burner; 12. Combustion chamber. DETAILED DESCRIPTION

[0019] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific protection scope of the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "several" and "a number" is two or more, unless otherwise clearly and specifically defined.

[0021] An efficient low-temperature SCR denitrification system, such as Figure 1 As shown, including:

[0022] An ammonia system, comprising an ammonia production device 1, an ammonia buffer tank 2 and an ammonia delivery pump skid 3, wherein the ammonia production device 1, the ammonia buffer tank 2 and the ammonia delivery pump skid 3 are sequentially connected, ammonia gas is prepared by the ammonia production device 1 and buffered in the ammonia buffer tank 2, and then delivered to the ammonia evaporation system by the ammonia delivery pump skid 3;

[0023] An evaporation and injection system, comprising an ammonia evaporator 5, an ammonia-air mixer 6, a dilution fan 10 and an ammonia injector 7, wherein the ammonia evaporator 5 is connected to the ammonia delivery pump skid 3 and a metering module is provided therebetween, the ammonia evaporator 5, the ammonia-air mixer 6 and the ammonia injector 7 are connected in sequence, the dilution fan 10 is connected to the ammonia-air mixer 6 and the ammonia injector 7 in sequence, and the dilution fan 10 is connected to the outlet of the SCR reactor 8, the dilution fan 10 guides the outlet flue gas of the SCR reactor 8 to the ammonia-air mixer 6 to mix and dilute with ammonia vapor, and then is injected into the flue by the ammonia injector 7 to react in the SCR reactor 8;

[0024] A combustion system, comprising a combustion chamber 12 and a burner 11, wherein the burner 11 is located in the combustion chamber 12, and the combustion chamber 12 is connected to the flue gas pipeline of the incinerator and connected to the ammonia injector 7, so that the flue gas of the incinerator enters the ammonia injector 7 after being heated by the combustion system;

[0025] The SCR reactor 8 is provided with a low-temperature catalyst 9 inside, and the low-temperature catalyst 9 is installed in layers inside the SCR reactor 8. The inlet of the SCR reactor 8 is connected with the ammonia injector 7, and the dilution fan 10 is respectively connected with the outlet of the ammonia-air mixer 6 and the SCR reactor 8, so that the dilution fan 10, the ammonia-air mixer 6, the ammonia injector 7, and the SCR reactor 8 are circulated and connected in sequence, and the flue gas and ammonia heated by the combustion system enter the SCR reactor 8 for reaction, and part of the flue gas at the outlet of the SCR reactor 8 is drained to the ammonia evaporation system to mix with the ammonia.

[0026] Preferably, in this embodiment, the ammonia water system further comprises a tail gas absorption tank 4 , and the tail gas absorption tank 4 is cyclically connected with the ammonia water buffer tank 2 , so that it can be used to recover and reuse the ammonia gas volatilized from the ammonia water buffer tank 2 .

[0027] Preferably, in this embodiment, the ammonia water delivery pump skid 3 is in circulation communication with the ammonia water buffer tank 2 , so that the ammonia water from the pump skid can flow back into the ammonia water buffer tank 2 .

[0028] Preferably, in this embodiment, the ammonia buffer tank 2 , the ammonia delivery pump skid 3 , and the ammonia evaporator 5 are cyclically connected in sequence, so that ammonia volatilized by the ammonia evaporator 5 can be recovered into the ammonia buffer tank 2 .

[0029] Working principle:

[0030] When the boiler flue temperature is low and does not meet the conventional catalyst reaction temperature, the utility model is provided with an ammonia system, an evaporation injection system, a combustion system, and an SCR reactor 8. By providing a combustion system and using a low-temperature SCR catalyst, ammonia of the ammonia system is transported to the ammonia evaporator 5. When the evaporation injection system is spraying ammonia, the flue gas is first heated by the combustion system and then passes through the ammonia injector 7. The ammonia injector 7 evenly sprays high-temperature flue gas and ammonia into the SCR reactor 8. The high-efficiency low-temperature catalyst 9 in the SCR reactor 8 only needs a relatively low temperature (150°C) to complete denitration, so that NOx emissions meet the standards, greatly reducing the natural gas consumption, thereby reducing the denitration cost.

[0031] The above is only a preferred embodiment of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-efficiency low-temperature SCR denitrification system, characterized in that: include: An ammonia system, comprising an ammonia production device, an ammonia buffer tank and an ammonia delivery pump skid, wherein the ammonia production device, the ammonia buffer tank and the ammonia delivery pump skid are connected in sequence; An evaporation injection system, comprising an ammonia evaporator, an ammonia-air mixer, a dilution fan and an ammonia injector, wherein the ammonia evaporator is connected to an ammonia delivery pump skid and a metering module is arranged therebetween, and the ammonia evaporator, the ammonia-air mixer and the ammonia injector are connected in sequence; A combustion system, comprising a combustion chamber and a burner, wherein the burner is located in the combustion chamber, and the combustion chamber is connected to a flue gas duct of an incinerator and connected to an ammonia injector; The SCR reactor is provided with a low-temperature catalyst inside, and the low-temperature catalyst is installed in layers in the SCR reactor. The inlet of the SCR reactor is connected to the ammonia injector, and the dilution fan is respectively connected to the ammonia-air mixer and the outlet of the SCR reactor.

2. According to claim 1, a high-efficiency low-temperature SCR denitration system is characterized in that: The ammonia water system further comprises a tail gas absorption tank, and the tail gas absorption tank is cyclically connected with the ammonia water buffer tank.

3. According to claim 1, a high-efficiency low-temperature SCR denitration system is characterized in that: The ammonia water delivery pump skid is in circulation communication with the ammonia water buffer tank.

4. According to claim 3, a high-efficiency low-temperature SCR denitration system is characterized in that: The ammonia water buffer tank, the ammonia water delivery pump skid and the ammonia water evaporator are cyclically connected in sequence.

Images