Novel ammonia-saving ammonia water evaporation and dilution system and SCR (Selective Catalytic Reduction) denitration device

Abstract

The utility model relates to the technical field of denitration, and discloses a novel ammonia-saving type ammonia water evaporation and dilution system and an SCR (Selective Catalytic Reduction) denitration device. The novel ammonia-saving ammonia water evaporation and dilution system comprises an ammonia water storage tank, an evaporator, an ammonia water main pipe connected with the ammonia water storage tank, an ammonia water regulating valve arranged on the ammonia water main pipe, an ammonia water spray gun arranged in the evaporator and connected with the ammonia water main pipe, a high-temperature flue gas pipeline connected with the evaporator, and a high-temperature dilution fan arranged on the high-temperature flue gas pipeline, two ends of the connecting pipe are respectively connected with an exhalation port of the breather valve on the ammonia water storage tank and the high-temperature flue gas pipeline; and the ammonia concentration meter is arranged on the high-temperature flue gas pipeline and is positioned between the connecting pipe and the evaporator. According to the ammonia gas recovery device, ammonia gas exhaled by the breather valve can be recycled, so that the pollution to the environment caused by ammonia gas emission to the air can be reduced, the consumption of ammonia water can be reduced, and the operation cost can be reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a denitration technical field especially relates to a novel ammonia saving type ammonia water evaporation dilution system and SCR denitration device. BACKGROUND

[0002] The tail gas discharged by industrial boilers and kilns contains a large amount of NO x , and the conventional treatment process is the SCR selective catalytic reduction process, and the reducing agent usually adopts liquid ammonia, urea or ammonia water, but liquid ammonia has great fire hazard, and urea has poor economy, so most of the present denitration projects adopt 15%-20% ammonia water as the denitration reducing agent. x That is, the high-temperature flue gas after denitration at 200-300 DEG C is extracted by a dilution fan, the remaining heat is utilized to evaporate and dilute the ammonia water, the ammonia-air mixture after evaporation is uniformly sprayed into a denitration reactor, reacts with NO x to generate N2 and H2O, and finally the content of NO in the flue gas is lower than the limit value of the national standard, achieving the standard discharge.

[0003] In the actual flue gas denitration engineering application, because the use amount of 20% ammonia water is large, the denitration device is matched with an ammonia water storage system, which mainly comprises an ammonia unloading pump, an ammonia water storage tank and an ammonia water conveying pump. The ammonia water storage tank is a normal-pressure storage container, in order to solve the possible negative pressure and overpressure in the ammonia water storage tank, a breather valve is generally designed in the ammonia water storage tank, when the negative pressure in the storage tank, the breather valve sucks the air in the atmosphere to keep the pressure in the tank stable, when the pressure in the storage tank is greater than the pressure setting value of the discharge spring of the breather valve, the breather valve is opened, the ammonia gas is discharged to the atmosphere, so that the pressure in the tank is maintained at normal pressure. In the process of overpressure, the ammonia gas discharged through the breather valve is released into the air, and the released ammonia is usually absorbed by water. This mode has the following disadvantages:

[0004] 1. The ammonia gas is directly released into the air, polluting the environment, the ammonia gas is a colorless gas with strong irritating odor, which can burn the skin, eyes and mucous membranes of respiratory organs, and pure ammonia gas can also cause fire or explosion when meeting fire;

[0005] 2. The released ammonia is absorbed by water, and the low-concentration ammonia water needs to be additionally increased by an ammonia water treatment or recovery device, increasing the complexity of the system;

[0006] 3. The released ammonia gas is not effectively utilized, causing the waste of ammonia and increasing the operation cost of the denitration system.

[0007] With the trend of cost reduction and efficiency increase, energy saving and emission reduction of production enterprises, it is very important to fully utilize the residual value of each substance for long-term development of enterprises. UTILITY MODEL CONTENT

[0008] The utility model aims at solving the technical problem existing in prior art. For this purpose, the utility model provides a novel ammonia-saving ammonia water evaporation dilution system and an SCR denitration device.

[0009] The utility model solves technical scheme that its technical problem adopts:

[0010] Firstly, a novel ammonia-saving ammonia water evaporation dilution system is provided, which comprises an ammonia water storage tank, an evaporator, an ammonia water main pipe connected with the ammonia water storage tank, an ammonia water regulating valve arranged on the ammonia water main pipe, an ammonia water spray gun arranged in the evaporator and connected with the ammonia water main pipe, a high-temperature flue gas pipeline connected with the evaporator, a high-temperature dilution fan arranged on the high-temperature flue gas pipeline, a communication pipe connected with the outlet of a breather valve on the ammonia water storage tank and the high-temperature flue gas pipeline at both ends, and an ammonia concentration meter arranged on the high-temperature flue gas pipeline between the communication pipe and the evaporator.

[0011] In some optional embodiments, first and second valves are arranged before and after the breather valve respectively, the second valve is a normally open ball valve, and the second valve is a regulating valve.

[0012] In some optional embodiments, the second valve is a manually adjustable valve, which is used to adjust the pressure of the outlet of the breather valve to be close to 0.

[0013] In some optional embodiments, the communication pipe is arranged on the high-temperature flue gas pipeline at the air inlet end of the high-temperature dilution fan, and the ammonia concentration meter is arranged at the air outlet end of the high-temperature dilution fan.

[0014] In some optional embodiments, an ammonia water flow meter is further arranged on the ammonia water main pipeline, the ammonia water regulating valve is an electric regulating valve, and the ammonia water flow meter, the ammonia water regulating valve and the ammonia concentration meter are all electrically connected with a PLC controller.

[0015] Secondly, an SCR denitration device provided with the novel ammonia-saving ammonia water evaporation dilution system is provided.

[0016] In some optional embodiments, a uniform distribution grid is further arranged between the evaporator of the novel ammonia-saving ammonia water evaporation dilution system and the denitration device.

[0017] Compared with the prior art, the utility model has the following beneficial effects:

[0018] 1. The utility model can recycle the ammonia gas emitted by the breather valve, which not only reduces the pollution caused by the emission of ammonia gas to the environment, but also reduces the consumption of ammonia water and the operating cost.

[0019] 2. Water or other substances are not needed to absorb the emitted ammonia, which reduces the investment in equipment for treating waste ammonia water and the cost of personnel operation.

[0020] 3. The system is modified on the original ammonia evaporation and dilution system, and only the necessary pipelines and ammonia concentration meters need to be added, so the modification cost is low;

[0021] 4. Interlocking control can be achieved through the ammonia concentration meter and the ammonia regulating valve using a PLC controller to reduce the flow of the ammonia main pipe so that the total ammonia amount in the exhaled ammonia and ammonia main pipe is basically consistent with the total ammonia amount required by the denitrification system;

[0022] 5. The arrangement of the uniformly distributed grid ensures that the ammonia entering the denitrification device is very uniform, resulting in a good denitrification effect and preventing excessive ammonia escape from the rear end of the denitrification device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. Among them:

[0024] Figure 1 It is a structural schematic diagram of a novel ammonia-saving ammonia water evaporation and dilution system provided by the utility model.

[0025] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0026] 1—Ammonia storage tank, 2—Evaporator, 3—Ammonia main pipe, 4—Ammonia regulating valve, 5—Ammonia flow meter, 6—Ammonia spray gun, 7—High-temperature flue gas pipeline, 8—High-temperature dilution fan, 9—Breathing valve, 10—Communication pipe, 11—Ammonia concentration meter, 12—First valve, 13—Second valve, 14—Uniformly distributed grid. DETAILED DESCRIPTION

[0027] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] In the description of the utility model, it is necessary to explain that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the utility model;

[0030] In addition, the description of the terms "first", "second" and the like in the utility model is only for the purpose of description, and cannot be understood as indicating or implying the relative importance thereof or implying the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include at least one of the features. The terms "mounting", "connection" and "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0031] In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that the ordinary skilled in the art can realize it, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the utility model.

[0032] Embodiment one

[0033] The embodiment provides a novel ammonia-saving ammonia water evaporation dilution system, which is an important part of an SCR denitration device. Figure 1 As shown in the figure, the novel ammonia-saving ammonia water evaporation dilution system comprises an ammonia water storage tank 1, an evaporator 2, an ammonia water main pipe 3, an ammonia water regulating valve 4, an ammonia water flowmeter 5, an ammonia water spray gun 6, a high-temperature flue gas pipeline 7, a high-temperature dilution fan 8, a breather valve 9, a connecting pipe 10, an ammonia concentration meter 11, a first valve 12, a second valve 13 and a PLC controller (not shown in the figure), wherein:

[0034] One end of the ammonia water main pipe 3 is connected to the ammonia water storage tank 1, and the ammonia water main pipe 1 is provided with an ammonia water conveying pump (not shown in the figure), the ammonia water regulating valve 4 and the ammonia water flowmeter 5, which are respectively used for supplying ammonia water for the SCR device, adjusting the ammonia water flow and monitoring the ammonia water flow, and the other end of the ammonia water main pipe 1 is connected to the ammonia water spray gun 6 in the evaporator 2.

[0035] The high-temperature flue gas pipeline 7 is connected to the evaporator 2, and the high-temperature dilution fan 8 is arranged on the high-temperature flue gas pipeline 7 to provide heat energy for the evaporation of ammonia water in the evaporator.

[0036] The one end of the communication pipe 10 is connected with the high-temperature flue gas pipe 7, and the other end is connected with the outlet of the breather valve 9 on the ammonia water storage tank 1. Preferably, the communication pipe 10 is arranged on the high-temperature flue gas pipe 7 at the air inlet end of the high-temperature dilution fan 8, and the ammonia discharged by the breather valve is absorbed by the negative pressure at the fan inlet. Since the extracted high-temperature flue gas is above 200℃, the dew point of the flue gas is far below the flue gas temperature, and thus the corrosion of the fan and the pipe at the rear end will not occur.

[0037] The first valve 12 and the second valve 13 are arranged respectively before and after the breather valve 9, wherein the first valve 12 is a normally open ball valve, and the second valve 9 is a manually adjusted valve, which is used to adjust the pressure of the outlet of the breather valve to be close to 0, so that the opening of the breather valve is not affected by the negative pressure of the fan, and at the same time, when the breather valve needs to be detected due to failure, the valves before and after the breather valve are closed to detect and repair the breather valve.

[0038] The ammonia concentration meter 11 is arranged on the high-temperature flue gas pipe 7 at the air outlet end of the high-temperature dilution fan 8, and is used to detect the ammonia water concentration in the high-temperature flue gas pipe in real time.

[0039] The PLC controller is electrically connected with the ammonia water flow meter 5, the ammonia water regulating valve 4 and the ammonia concentration meter 11. The interlocking control of the ammonia concentration meter and the ammonia water regulating valve can be realized by using the PLC controller.

[0040] Working principle: when the ammonia water storage tank is overpressure due to unloading of ammonia or overhigh temperature, the ammonia gas at the upper part of the storage tank passes through the normally open first valve, then passes through the outlet of the breather valve, the second valve and the communication pipe to enter the high-temperature flue gas pipe (when the ammonia water storage tank is under negative pressure, the air is supplemented by the air inlet of the breather valve); under the driving of the high-temperature dilution fan, the high-temperature dilution wind carrying the discharged ammonia flows through the ammonia concentration meter, and the ammonia concentration in the dilution wind at this time is detected, and then the high-temperature dilution wind enters the evaporator to evaporate the ammonia water provided by the ammonia water main pipe; the value of the ammonia concentration meter is calculated, and the ammonia water regulating valve of the ammonia water main pipe is interlocked, so that the valve opening is appropriately reduced, and the final value of the reduced valve opening is fed back by the ammonia water flow meter; the calculated and adjusted ammonia water is atomized into 40-60μm mist droplets by the ammonia water spray gun, and then enters the evaporator, the small mist droplets are evaporated into ammonia-air mixed gas (the mixed gas concentration ratio of ammonia and air is below the safe concentration of 5%) by the high-temperature dilution wind, and then the ammonia-air mixed gas is uniformly sprayed into the denitration device to complete the denitration reaction. The operation of the above facilities and the interlocking control of the opening of the ammonia water regulating valve are all completed on the PLC controller.

[0041] Preferably, a uniform distribution grid 14 is further arranged between the evaporator 2 and the denitration device, so that the ammonia entering the denitration device is very uniform, the denitration effect is good, and the ammonia escape after the denitration device will not exceed the standard.

[0042] The above merely illustrates the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, are all included in the patent protection scope of the present application.

Claims

1. A novel ammonia water evaporation dilution system with ammonia saving, comprising an ammonia water storage tank, an evaporator, an ammonia water main pipe connected with the ammonia water storage tank, an ammonia water regulating valve arranged on the ammonia water main pipe, an ammonia water spray gun arranged in the evaporator and connected with the ammonia water main pipe, a high-temperature flue gas pipeline connected with the evaporator, and a high-temperature dilution fan arranged on the high-temperature flue gas pipeline; characterized in that: The connecting pipe is connected with the outlet of the breathing valve on the ammonia storage tank and the high-temperature flue gas pipeline respectively, and the ammonia concentration meter is arranged on the high-temperature flue gas pipeline between the connecting pipe and the evaporator.

2. The novel ammonia sparing ammonia water evaporation dilution system according to claim 1, characterized in that: The first valve and the second valve are arranged before and after the breathing valve respectively, the second valve is a normally open ball valve, and the second valve is an adjusting valve.

3. The novel ammonia sparing ammonia water evaporation dilution system as claimed in claim 2, wherein: The second valve is a manual adjusting valve, which is used for adjusting the pressure of the breathing valve outlet point to be close to 0.

4. The novel Ammonia-Evaporation-Dilution-System with Ammonia-Saving according to claim 1, characterized in that The connecting pipe is arranged on the high-temperature flue gas pipeline at the air inlet end of the high-temperature dilution fan, and the ammonia concentration meter is arranged at the air outlet end of the high-temperature dilution fan.

5. The novel Ammonia-Evaporation-Dilution-System with Ammonia-Saving according to claim 1, characterized in that The ammonia water flow meter is further arranged on the ammonia water main line, the ammonia water adjusting valve is an electric adjusting valve, and the ammonia water flow meter, the ammonia water adjusting valve and the ammonia concentration meter are electrically connected with the PLC controller.

6. An SCR de-NOx device characterized by comprising: The new ammonia-saving ammonia water evaporation dilution system is installed.

7. The SCR deNOx device of claim 6, wherein: An equal distribution grid is further arranged between the evaporator and the denitration device of the new ammonia-saving ammonia water evaporation dilution system.

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