Cement kiln flue gas demercuration system

Abstract

The utility model provides a cement kiln flue gas demercuration system, the cement kiln flue gas demercuration system comprises a reactor, a waste heat boiler, a humidifying tower, a dust collector, a flue gas pipeline and a dispenser, a catalyst for converting elemental mercury into divalent mercury can be placed in the reactor, the waste heat boiler, the humidifying tower and the dust collector are sequentially arranged, and the dispenser is arranged in the reactor. The reactor, the waste heat boiler, the humidifying tower and the dust collector are communicated through the flue gas pipeline, and the dispenser is used for dispensing an adsorbent into the flue gas pipeline connected with an inlet of the dust collector. According to the cement kiln flue gas demercuration system disclosed by the embodiment of the utility model, in the whole demercuration process, mercury is pretreated, namely elemental mercury is converted into divalent mercury which is more easily adsorbed, so that the quantity of adsorbents required to be fed by the feeding device is reduced, the operation cost is reduced, and the flue gas demercuration efficiency is also improved.

Description

Technical Field

[0001] The utility model relates to the technical field of mercury removal from flue gas, in particular to a mercury removal system for cement kiln flue gas. Background Art

[0002] Mercury is a highly toxic heavy metal element with persistence, long-distance migration and bioaccumulation. It can enter the human body through air, water and food, causing serious damage to the liver, kidneys and central nervous system. The cement industry is one of the main industrial emission sources of mercury, and the annual mercury emission is only second to coal combustion and non-ferrous metal smelting.

[0003] In the commonly used mercury removal technologies for flue gas, carbon-based adsorbents, calcium-based adsorbents, mineral adsorbents or fly ash adsorbents are used to remove mercury. These technologies adsorb mercury through adsorbents. However, due to the large volume of cement kiln flue gas, which can generally reach hundreds of thousands of standard cubic meters per hour, the cost of using adsorbents to remove mercury is relatively high. In addition, the adsorbents are also prone to clogging problems, thus affecting the mercury removal efficiency of the flue gas. Summary of the Utility Model

[0004] The utility model provides a mercury removal system for cement kiln flue gas, which is used to solve the defects in the prior art that the cost of removing mercury by adsorbents is relatively high and the mercury removal efficiency of the flue gas is easily affected, and realizes low-cost mercury removal and high-efficiency mercury removal.

[0005] An embodiment of the utility model discloses a mercury removal system for cement kiln flue gas, including:

[0006] A reactor, in which a catalyst for converting elemental mercury into divalent mercury can be placed;

[0007] A waste heat boiler, a humidification tower and a dust collector, which are arranged in sequence;

[0008] A flue gas pipeline, through which the reactor, the waste heat boiler, the humidification tower and the dust collector are connected;

[0009] A dispenser, which is used to put adsorbents into the flue gas pipeline connected to the inlet of the dust collector.

[0010] In some embodiments, the reactor is arranged upstream of the waste heat boiler, and the mercury removal system for cement kiln flue gas includes a first pipeline, one end of which is connected to the cement kiln preheater system, and the other end of which is connected to the inlet of the reactor.

[0011] In some embodiments, the reactor is provided downstream of the waste heat boiler. The cement kiln flue gas mercury removal system includes a first pipeline, one end of which is communicated with the cement kiln preheater system, and the other end of which is communicated with the inlet of the waste heat boiler.

[0012] In some embodiments, the cement kiln flue gas mercury removal system includes a first fan, which is arranged between the waste heat boiler and the humidification tower, and the first fan is used for conveying the gas flow in the waste heat boiler to its downstream.

[0013] In some embodiments, a spraying component is arranged in the humidification tower, and the spraying component is used for spraying water mist into the humidification tower.

[0014] In some embodiments, a chimney is arranged at the end of the cement kiln flue gas mercury removal system, and the chimney is communicated with the dust collector.

[0015] In some embodiments, the cement kiln flue gas mercury removal system includes a second fan, which is arranged between the dust collector and the chimney, and the second fan is used for conveying the gas flow in the dust collector to the chimney.

[0016] In some embodiments, the cement kiln flue gas mercury removal system includes a controller and an on-line mercury analyzer. The on-line mercury analyzer is arranged in the chimney, and both the on-line mercury analyzer and the dispenser are electrically connected to the controller.

[0017] In some embodiments, the cement kiln flue gas mercury removal system includes a raw material silo. The reactor, the waste heat boiler and the humidification tower are all provided with dust outlets, and each dust outlet is communicated with the raw material silo.

[0018] In some embodiments, the cement kiln flue gas mercury removal system includes a discharging device, which is connected to the dust collector, and the discharging device is used for discharging the collected dust in the dust collector.

[0019] In the cement kiln flue gas mercury removal system according to the embodiments of the present utility model, during the whole mercury removal process, due to the pretreatment of mercury, that is, converting elemental mercury into divalent mercury which is easier to be adsorbed, the amount of adsorbent required to be dispensed by the dispenser is reduced. On the one hand, the operation cost is reduced. On the other hand, the reduction of the adsorbent dispensing amount can effectively avoid the blocking situation during the use of the adsorbent. Thus, not only the maintenance cost of the cement kiln flue gas mercury removal system and the shutdown and maintenance time are reduced, but also the mercury removal efficiency of the cement kiln flue gas mercury removal system is improved. Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the present utility model or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of a mercury removal system for cement kiln flue gas provided by the present utility model.

[0022] Reference numerals:

[0023] 1, reactor; 2, waste heat boiler; 3, first fan; 4, humidifying tower; 5, dispenser; 6, dust collector; 7, second fan; 8, chimney; 9, raw material silo; 10, discharge device; 11, cement kiln preheater system. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the present utility model clearer, the following will clearly and completely describe the technical solutions in the present utility model with reference to the drawings in the present utility model. Obviously, the described embodiments are some but not all of the embodiments of the present utility model. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present utility model.

[0025] An embodiment of the present utility model discloses a mercury removal system for cement kiln flue gas, including a reactor 1, a waste heat boiler 2, a humidifying tower 4, a dust collector 6 and a dispenser 5.

[0026] As Figure 1 shown, an embodiment of the present utility model discloses a mercury removal system for cement kiln flue gas, including a reactor 1, a waste heat boiler 2, a humidifying tower 4, a dust collector 6 and a dispenser 5.

[0027] A catalyst for converting elemental mercury into divalent mercury can be placed in the reactor 1. The waste heat boiler 2, the humidifying tower 4 and the dust collector 6 are arranged in sequence.

[0028] The reactor 1, the waste heat boiler 2, the humidifying tower 4 and the dust collector 6 are connected through a flue gas pipeline.

[0029] The dispenser 5 is used to inject an adsorbent into the flue gas pipeline connected to the inlet of the dust collector 6.

[0030] The catalyst can convert elemental mercury in the flue gas into divalent mercury, such as vanadium tungsten titanium catalyst, iron-based catalyst or platinum-based catalyst, etc. These catalysts have good oxidation performance for elemental mercury under higher temperature conditions and can effectively convert elemental mercury into divalent mercury.

[0031] The position of the reactor 1 is arranged according to the actual working conditions. For example, the reactor 1 can be set upstream of the waste heat boiler 2. At this time, the reactor 1 is in an environment of high temperature and high dust. Or, the reactor 1 can be set downstream of the waste heat boiler 2. At this time, the reactor 1 is in an environment of medium temperature and medium dust.

[0032] The adsorbent is activated carbon or modified activated carbon.

[0033] When the cement kiln flue gas mercury removal system of the embodiment of the present utility model is working, the flue gas flows out from the cement kiln preheater system 11 and then enters the cement kiln flue gas mercury removal system. The elemental mercury that is not easily adsorbed in the flue gas is converted into divalent mercury that is more easily captured by the adsorbent when passing through the reactor 1.

[0034] Subsequently, the flue gas containing divalent mercury enters the dust collector 6, and the dispenser 5 injects the adsorbent into the flue gas pipeline connected to the inlet of the dust collector 6. The adsorbent is mixed with the flue gas in the flue gas pipeline and then flows together to the dust collector 6. During the mixing process, the adsorbent can effectively adsorb the divalent mercury in the flue gas, thereby reducing the mercury content in the flue gas and making the flue gas meet the emission standards.

[0035] In the cement kiln flue gas mercury removal system of the embodiment of the present utility model, during the entire mercury removal process, since the mercury is pretreated, that is, the elemental mercury is converted into divalent mercury that is more easily adsorbed, the amount of the adsorbent required to be injected by the dispenser 5 is reduced. On the one hand, this reduces the operating cost. On the other hand, the reduction in the injection amount of the adsorbent can effectively avoid the blockage situation during the use of the adsorbent. Thus, not only the maintenance cost and the shutdown and overhaul time of the cement kiln flue gas mercury removal system are reduced, but also the mercury removal efficiency of the cement kiln flue gas mercury removal system is improved.

[0036] Therefore, the cement kiln flue gas mercury removal system of the embodiment of the present utility model can reduce the amount of the adsorbent required to be injected by the dispenser 5 and can improve the mercury removal efficiency.

[0037] Optionally, the dust collector 6 is a bag dust collector 6. A plurality of adsorption chambers are provided in the bag dust collector 6. The adsorbent is mixed with the flue gas in the flue gas pipeline and adsorbs the mercury in the flue gas, and then is transported to each adsorption chamber of the bag dust collector 6. The adsorbent that adsorbs mercury is adhered to the filter bags in the adsorption chamber and gradually accumulates on the filter bags to form a filter cake layer, thereby removing the mercury in the cement kiln flue gas.

[0038] In some embodiments, the reactor 1 is arranged upstream of the waste heat boiler 2. The cement kiln flue gas mercury removal system includes a first pipeline. One end of the first pipeline is communicated with the cement kiln preheater system 11, and the other end of the first pipeline is communicated with the inlet of the reactor 1.

[0039] For example, as Figure 1As shown, after the flue gas flows out of the cement kiln preheater system 11, it first enters the reactor 1 through the first pipeline and then enters the waste heat boiler 2. In this layout, the reactor 1 is in a high-temperature and high-dust environment and can effectively oxidize elemental mercury into divalent mercury.

[0040] In some embodiments, the reactor 1 is arranged downstream of the waste heat boiler 2. The mercury removal system for cement kiln flue gas includes a first pipeline. One end of the first pipeline is connected to the cement kiln preheater system 11, and the other end of the first pipeline is connected to the inlet of the waste heat boiler 2.

[0041] For example, as Figure 1 shown, after the flue gas flows out of the cement kiln preheater system 11, it first enters the waste heat boiler 2 through the first pipeline and then enters the reactor 1. In this layout, the reactor 1 is in a medium-temperature and medium-dust environment and can also effectively oxidize elemental mercury into divalent mercury.

[0042] In some embodiments, the mercury removal system for cement kiln flue gas includes a first fan 3. The first fan 3 is arranged between the waste heat boiler 2 and the humidifying tower 4. The first fan 3 is used to transport the gas flow in the waste heat boiler 2 to its downstream.

[0043] For example, as Figure 1 shown, the first fan 3 extracts the flue gas after heat exchange from the waste heat boiler 2 and transports it to the humidifying tower 4. The first fan 3 is used to ensure that the flue gas can be stably transported from the waste heat boiler 2 to the downstream humidifying tower 4.

[0044] In some embodiments, a spraying component is arranged inside the humidifying tower 4. The spraying component is used to spray water mist into the humidifying tower 4.

[0045] For example, a spraying component is arranged inside the humidifying tower 4. The spraying component is used to spray fine water mist into the tower to reduce the temperature of the flue gas.

[0046] Optionally, the spraying component includes a plurality of nozzles arranged at intervals.

[0047] In some embodiments, a chimney 8 is arranged at the end of the mercury removal system for cement kiln flue gas. The chimney 8 is connected to the dust collector 6.

[0048] For example, as Figure 1 shown, in the dust collector 6, the mercury content of the flue gas after adsorption treatment has been greatly reduced, and then it enters the chimney 8 and is discharged through the chimney 8.

[0049] The height and diameter of the chimney 8 need to be designed according to the flue gas emission volume and environmental protection requirements to ensure that the discharged flue gas can diffuse to a high enough atmosphere to reduce ground pollution.

[0050] In some embodiments, the mercury removal system for cement kiln flue gas includes a second fan 7, which is arranged between the dust collector 6 and the chimney 8, and the second fan 7 is used to transport the air flow in the dust collector 6 to the chimney 8.

[0051] For example, as Figure 1 shown, the second fan 7 extracts the purified flue gas from the dust collector 6 and transports it to the chimney 8.

[0052] In some embodiments, the mercury removal system for cement kiln flue gas includes a controller and an on-line mercury analyzer. The on-line mercury analyzer is arranged in the chimney 8, and both the on-line mercury analyzer and the dispenser 5 are electrically connected to the controller.

[0053] For example, the on-line mercury analyzer is arranged in the chimney 8 to monitor the mercury content in the discharged gas in real time. The on-line mercury analyzer is electrically connected to the controller through a cable or wireless communication to ensure real-time data transmission. When the mercury content detected by the on-line mercury analyzer exceeds the preset threshold, the controller controls the dispenser 5 to dispense the adsorbent to adsorb the mercury in the flue gas. When the mercury content detected by the on-line mercury analyzer does not exceed the preset threshold, the controller controls the dispenser 5 to stop dispensing the adsorbent.

[0054] In the mercury removal system for cement kiln flue gas implemented by the present utility model, the on-line mercury analyzer can timely feedback the monitoring results, so as to automatically control the dispensing of the adsorbent, which not only effectively prevents the mercury from exceeding the standard in emissions, but also avoids the overuse of the adsorbent, thus saving costs. Moreover, it can reduce the probability of adsorbent blockage, thereby reducing the maintenance frequency of the mercury removal system for cement kiln flue gas, and further improving the mercury removal efficiency of the mercury removal system for cement kiln flue gas.

[0055] In some embodiments, the mercury removal system for cement kiln flue gas includes a raw material silo 9. The reactor 1, the waste heat boiler 2, and the humidifying tower 4 are all provided with dust outlets, and each dust outlet is communicated with the raw material silo 9.

[0056] For example, as Figure 1 shown, the dust outlets of the reactor 1, the waste heat boiler 2, and the humidifying tower 4 are centrally communicated with the raw material silo 9, which simplifies the dust management process. The dust stored in the raw material silo 9 enters the cement kiln system along with the cement production raw materials.

[0057] In some embodiments, the mercury removal system for cement kiln flue gas includes a discharging device 10, which is connected to the dust collector 6, and the discharging device 10 is used to discharge the collected dust in the dust collector 6.

[0058] After the adsorbent in the dust collector 6 adsorbs mercury, the adsorbed mercury can be removed through subsequent treatment (such as pyrolysis regeneration), or safely disposed of as hazardous waste. The collected dust in the dust collector 6 is discharged from the dust collector 6 through the discharging device 10. For example, the discharging device 10 is a screw conveyor or a scraper conveyor, etc.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A mercury removal system for cement kiln flue gas, characterized in that, Comprising: A reactor, in which a catalyst for converting elemental mercury into divalent mercury can be placed; A waste heat boiler, a humidification tower and a dust collector, which are arranged in sequence; A flue gas pipeline, through which the reactor, the waste heat boiler, the humidification tower and the dust collector are connected; A dispenser, which is used to inject an adsorbent into the flue gas pipeline connected to the inlet of the dust collector.

2. The mercury removal system for cement kiln flue gas according to claim 1, characterized in that, The reactor is arranged upstream of the waste heat boiler. The mercury removal system for cement kiln flue gas includes a first pipeline, one end of which is connected to the cement kiln preheater system, and the other end of which is connected to the inlet of the reactor.

3. The mercury removal system for cement kiln flue gas according to claim 1, characterized in that, The reactor is arranged downstream of the waste heat boiler. The mercury removal system for cement kiln flue gas includes a first pipeline, one end of which is connected to the cement kiln preheater system, and the other end of which is connected to the inlet of the waste heat boiler.

4. The mercury removal system for cement kiln flue gas according to claim 1, wherein The mercury removal system for cement kiln flue gas includes a first fan, which is arranged between the waste heat boiler and the humidification tower and is used to convey the gas flow in the waste heat boiler to its downstream.

5. The mercury removal system for cement kiln flue gas according to claim 1, wherein, A spraying component is arranged in the humidification tower, and the spraying component is used to spray water mist into the humidification tower.

6. The mercury removal system for cement kiln flue gas according to claim 1, wherein, A chimney is arranged at the end of the mercury removal system for cement kiln flue gas, and the chimney is connected to the dust collector.

7. The mercury removal system for cement kiln flue gas according to claim 6, wherein, The mercury removal system for cement kiln flue gas includes a second fan, which is arranged between the dust collector and the chimney and is used to convey the gas flow in the dust collector to the chimney.

8. The mercury removal system for cement kiln flue gas according to claim 6, wherein, The mercury removal system for cement kiln flue gas includes a controller and an on-line mercury analyzer. The on-line mercury analyzer is arranged in the chimney, and both the on-line mercury analyzer and the dispenser are electrically connected to the controller.

9. The mercury removal system for cement kiln flue gas according to claim 1, characterized in that The mercury removal system for cement kiln flue gas includes a raw material storage bin. The reactor, the waste heat boiler and the humidification tower are all provided with dust outlets, and each dust outlet is connected to the raw material storage bin.

10. The mercury removal system for cement kiln flue gas according to claim 1, wherein The mercury removal system for cement kiln flue gas includes a discharging device, which is connected to the dust collector and is used to discharge the collected dust in the dust collector.

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