A cement kiln deamination and dust removal system and method

Abstract

The embodiment of the present invention relates to the technical field of comprehensive treatment of cement kiln flue gas pollutants, and provides a cement kiln ammonia removal and dust removal system and method. The cement kiln ammonia removal and dust removal system provided by the embodiment of the present invention includes: a multi-stage ammonia capture device, each stage of the ammonia capture device is provided with an ammonia adsorbent, and the ammonia adsorbent can adsorb ammonia molecules in the flue gas on the surface or inside of the ammonia adsorbent; a preheater, the preheater is connected to the multi-stage ammonia capture device, wherein the preheater receives the ammonia adsorbent after adsorbing the ammonia molecules, and preheats it to achieve separation of ammonia and ammonia adsorbent, and then the ammonia is reused. The cement kiln ammonia removal and dust removal system provided by the embodiment of the present invention improves the adsorption rate of ammonia by setting a multi-stage ammonia capture device, effectively purifies the flue gas, and solves the problem of excessive ammonia in the flue gas emission process. At the same time, the ammonia molecules captured by the ammonia capture device are separated from the ammonia adsorbent, and then the ammonia is reused to avoid waste of resources.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive treatment of cement kiln flue gas pollutants, and in particular to a cement kiln deammoniation and dust removal system and method. Background Art

[0002] Selective non-catalytic reduction (SNCR) technology is referred to as SNCR denitrification technology. It is the most widely used technology in the treatment of nitrogen oxides (denitrification). SNCR denitrification technology sprays a reducing agent containing amino groups (such as ammonia water, urea solution, etc.) into the furnace at a temperature range of 850-950℃ to react with NO in the flue gas. X A reduction reaction occurs, generating nitrogen and water. In actual production, the efficiency of SNCR denitrification technology is usually only 50-80%, and it is closely related to factors such as the selection of denitrification location, the effect of the spray gun, and the composition of the flue gas. X The emission limit requirements are becoming more and more stringent. Many cement companies increase the amount of ammonia spray to control lower NO X , but not with NO X The ammonia produced by the reaction will escape, causing the chimney ammonia emission to easily exceed the standard. The international standard for ammonia emission is 8mg / Nm 3 Below, the requirements are very strict.

[0003] Selective catalytic reduction (SCR) technology, referred to as SCR denitrification technology, is a denitrification technology that has just emerged in the past two years in addition to SNCR denitrification technology. This technology is already very mature in other industries such as electricity and steel, but it is just starting in the cement industry. Its technical principle is basically the same as the main reaction of SNCR technology. Under the action of a catalyst, ammonia is injected into the flue gas at 280-420℃ to convert NO X The SCR denitrification efficiency can reach more than 90%, which greatly improves the utilization rate of ammonia and ensures that NO X Ultra-low emissions also ensure that ammonia escape does not exceed the standard. However, the investment in SCR denitrification technology is huge. A 5,000t / d cement production line requires a one-time investment of about 30 million yuan, and the operating cost is also high, about 3-7 yuan / tcl, which seriously restricts the development of SCR denitrification technology.

[0004] Under the current new situation of ultra-low nitrogen oxide emissions, there are two main problems: First, low-cost SNCR denitrification technology wants to achieve NO X Ultra-low emissions, the problem of ammonia escape cannot be solved; second, SCR denitrification technology can simultaneously achieve NO XUltra-low emissions and ammonia slip do not exceed the standards, but the investment and operating costs are very high.

[0005] Ammonia capture technology is currently less used. Ammonia can be captured by absorbing it with water, but there are also corresponding problems: first, the construction cost of denitrification and desulfurization towers is high. If the factory does not have relevant supporting facilities and needs to add them separately, the investment cost is high; second, the anti-escape measure of ammonia is to utilize its solubility in water to absorb it. Water has a strong ability to dissolve ammonia at room temperature and pressure, but its ability to dissolve ammonia is greatly reduced at higher temperatures. In order to ensure the capture of ammonia escape, the demand for water is relatively large, and water treatment will also increase the cost significantly.

[0006] If you can solve NO at the same time X It can solve the problem of ammonia escape and reduce investment and operating costs, which will be very necessary and meaningful for cement companies to control air pollution. Summary of the invention

[0007] In order to solve the problems of excessive ammonia emissions and high production costs caused by ammonia capture in the prior art, an embodiment of the present invention provides a cement kiln ammonia removal and dust removal system and a cement kiln ammonia removal and dust removal method.

[0008] According to one aspect of the present invention, an embodiment of the present invention provides a cement kiln ammonia removal and dust removal system, comprising: a multi-stage ammonia capture device, each stage of the ammonia capture device is provided with an ammonia adsorbent, and the ammonia adsorbent can adsorb ammonia molecules in the flue gas on the surface or inside of the ammonia adsorbent; a preheater, the preheater is connected to the multi-stage ammonia capture device, wherein the preheater receives the ammonia adsorbent after adsorbing ammonia molecules, and preheats the preheater to achieve separation of ammonia and the ammonia adsorbent, thereby reusing the ammonia.

[0009] According to one embodiment of the present invention, each stage of the ammonia capture device includes: a dust collector, with a first pipe and a second pipe connected to both ends of the dust collector respectively; an injection point, which is located upstream of the dust collector and is used to spray powdered ammonia adsorbent to adsorb ammonia molecules in the flue gas; wherein the first pipe is connected to the injection point, and the second pipe is connected to the chimney.

[0010] According to one embodiment of the present invention, a powdered ammonia adsorbent is disposed in at least one of the first pipe and the second pipe.

[0011] According to one embodiment of the present invention, a reactor is disposed on at least one of the first pipeline and the second pipeline, and a block-shaped ammonia adsorbent is disposed in the reactor.

[0012] According to one embodiment of the present invention, the cement kiln ammonia removal and dust removal system also includes: an ammonia capture and conveying device, which is connected to the injection point to convey the powdered ammonia adsorbent to the injection point through a third pipe; wherein the ammonia capture and conveying device includes: a silo, the lower part of which is connected to a material discharge meter; a conveying pipeline, which is connected to the material discharge meter; a blower, which is connected to the conveying pipeline to spray the powdered ammonia adsorbent in the silo to the injection point after passing through the material discharge meter, the conveying pipeline and the third pipeline; wherein a valve is provided on the third pipeline to adjust the injection position of the injection point.

[0013] According to one embodiment of the present invention, the cement kiln ammonia removal and dust removal system also includes: a return ash conveying device, a raw material homogenization bin and a closed shell, the return ash conveying device is connected to the first dust collector to convey the powdered ammonia adsorbent and dust passing through the first dust collector to the raw material homogenization bin, wherein the closed shell is respectively provided on the top of the first dust collector and the raw material homogenization bin.

[0014] According to one embodiment of the present invention, the cement kiln deammonification and dust removal system also includes: a first feed pipe and a second feed pipe, wherein the first feed pipe and the second feed pipe are respectively arranged corresponding to the second dust collector and the third dust collector, wherein the first feed pipe is connected to the ash return conveying device, and the second feed pipe is connected to the raw material homogenization storage.

[0015] According to one embodiment of the present invention, the cement kiln deammonification and dust removal system also includes a hoist, which includes: a first hoist, a first end of the first hoist is connected to the ash return conveying device, and a second end of the first hoist is connected to a raw material homogenization bin; a second hoist, a first end of the second hoist is connected to the outlet of the raw material homogenization bin, and a second end of the second hoist is connected to the inlet of the preheater.

[0016] According to one embodiment of the present invention, the cement kiln deammonification and dust removal system also includes: a rotary kiln, which is connected to the preheater; a raw mill device, the inlet of the raw mill device is connected to the outlet of the preheater, and the outlet of the raw mill device is connected to the inlet of the ammonia capture device; a humidifying tower device, which is arranged in parallel with the raw mill device, and the inlet of the humidifying tower device is connected to the outlet of the preheater, and the outlet of the humidifying tower device is connected to the inlet of the ammonia capture device; a plurality of chimneys, each of which is arranged corresponding to the dust collector and connected to the dust collector.

[0017] According to another aspect of the present invention, there is provided a method for deamination and dust removal using the cement kiln deamination and dust removal system as described above, comprising:

[0018] The raw materials are prepared in the raw mill, and the prepared powdered raw materials enter the raw material homogenization silo, and then are sent to the preheater and rotary kiln to burn cement;

[0019] The smoke and dust generated in the cement preparation process are subjected to ammonia molecule adsorption and dust removal in the primary ammonia capture device, and the powdered ammonia adsorbent adsorbed with ammonia molecules and part of the dust and ammonia lost during the dust transportation process enter the secondary ammonia capture device for ammonia molecule adsorption and dust removal, and the ammonia adsorbent adsorbed with ammonia molecules and the dust are lifted and then enter the raw material homogenization silo;

[0020] The flue gas after the adsorption of ammonia molecules at each stage is discharged from the chimney corresponding to the ammonia capture device. Part of the dust and ammonia lost in the raw material homogenization warehouse is subjected to ammonia molecule adsorption in the three-stage ammonia capture device. The ammonia adsorbent and dust adsorbed with ammonia molecules enter the raw material homogenization warehouse, and enter the preheater together with the powdered raw material through lifting, so as to realize the separation of the ammonia adsorbent and the ammonia molecules, so as to make secondary use of the ammonia.

[0021] The cement kiln ammonia removal and dust removal system provided in the embodiment of the present invention improves the adsorption rate of ammonia by setting a multi-stage ammonia capture device, reduces the emission of ammonia into the atmosphere, effectively purifies the flue gas, and solves the problem of excessive ammonia in the flue gas emission process after SNCR denitrification. At the same time, the ammonia molecules captured by the ammonia capture device are separated from the ammonia adsorbent in the preheater, and the ammonia is reused to avoid waste of resources. In addition, the cement kiln ammonia removal and dust removal system provided in the embodiment of the present invention has a simple process and a simple device, which effectively reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of the structure of a cement kiln deammoniation and dust removal system provided by an embodiment of the present invention;

[0024] Figure 2 for Figure 1 The structural schematic diagram of the ammonia capture device shown;

[0025] Figure 3 The schematic diagram of the arrangement position of the reactor in one embodiment of the present invention;

[0026] Figure 4This is a schematic diagram of the arrangement position of the reactor in another embodiment of the present invention.

[0027] Description of reference numerals:

[0028] 1-rotary kiln; 2-preheater; 3-raw material grinding device; 4-humidifying tower device; 5-first injection point; 6-first dust collector; 7-first chimney; 8-ash return conveying device; 9-enclosed casing; 11-first elevator; 12-second elevator; 13-raw material homogenization warehouse; 14-silo; 15-feeding metering device; 16-conveyance pipeline; 17-blower; 18-valve; 20-reactor; 51-second injection point; 61-second dust collector; 71-second chimney; 81-first discharge pipe; 101-first pipeline; 102-second pipeline; 103-third pipeline; 104-bypass pipeline; 511-third injection point; 611-third dust collector; 711-third chimney; 811-second discharge pipe. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In addition, in the description of the present invention, unless otherwise specified, "multiple", "multiple roots", and "multiple groups" mean two or more, and "several", "several roots", and "several groups" mean one or more.

[0032] Now refer to Figures 1 to 4 , the embodiments provided by the present invention are described. It should be understood that the following description is only an illustrative embodiment of the present invention and does not constitute any particular limitation to the present invention.

[0033] In one embodiment of the present invention, the cement kiln ammonia removal and dust removal system includes: a multi-stage ammonia capture device and a preheater 2. Specifically, a certain amount of thermal nitrogen oxides will be generated during the cement preparation process. In order to effectively reduce the content of nitrogen oxides, the SNCR denitrification technology is usually used, that is, a reducing agent such as ammonia water or urea is sprayed into an appropriate position to cause NH3 produced by ammonia water or urea to react with nitrogen oxides for reduction, thereby reducing the emission of nitrogen oxides. However, in the actual process, due to the limited efficiency of SNCR denitrification, ammonia will be discharged along with the flue gas.

[0034] Ammonia adsorbent is provided in each stage of ammonia capture device. Ammonia adsorbent can react with ammonia mixed in flue gas through physical and chemical action, and adsorb ammonia molecules on the surface or inside of ammonia adsorbent. After the flue gas passes through the multi-stage ammonia capture device for adsorption and dust removal, the ammonia content in the flue gas can be effectively reduced. After the ammonia adsorbent in the multi-stage ammonia capture device adsorbs ammonia molecules, it enters the preheater 2. As the flue gas temperature in the preheater 2 becomes higher and higher, ammonia is separated from the ammonia adsorbent. The separated ammonia can be used as a reducing agent for nitrogen oxides, or react with sulfur dioxide to form sulfate or sulfite, so that ammonia can be reused for a second time, and the content of nitrogen oxides in the system can also be reduced.

[0035] Furthermore, the preheater 2 includes a five-stage cyclone and a decomposition furnace, and the temperature in the cyclone is different from that in the decomposition furnace. The ammonia adsorbent can directly enter the cyclone or directly enter the decomposition furnace. Specifically, when the ammonia adsorbent directly enters the decomposition furnace, the temperature in the decomposition furnace is 850-1000°C, and the ammonia in the ammonia adsorbent is released, which reacts with nitrogen oxides to perform denitrification treatment, thereby realizing the secondary utilization of ammonia; when the ammonia adsorbent enters the first-stage cyclone, the temperature in the first-stage cyclone is 280-350°C, and the ammonia in the ammonia adsorbent is released, reacts with SO2, and plays a role in desulfurization, thereby performing secondary utilization of ammonia.

[0036] It should be noted that the multi-stage ammonia capture device can be single-stage or multi-stage, and the number of stages can be determined according to specific working conditions.

[0037] The cement kiln ammonia removal and dust removal system provided in the embodiment of the present invention improves the adsorption rate of ammonia by setting a multi-stage ammonia capture device, reduces the emission of ammonia into the atmosphere, effectively purifies the flue gas, and solves the problem of excessive ammonia in the flue gas emission process after SNCR denitrification. At the same time, the ammonia molecules captured by the ammonia capture device are separated from the ammonia adsorbent in the preheater, and the ammonia is reused to avoid waste of resources. In addition, the cement kiln ammonia removal and dust removal system provided in the embodiment of the present invention has a simple process and a simple device, which effectively reduces the production cost.

[0038] In one embodiment of the present invention, each stage of the ammonia capture device includes: a dust collector, an injection point, a first pipeline, and a second pipeline. The following takes the first stage of the ammonia capture device as an example to explain in detail the working principle of each stage of the ammonia capture device. Figure 2 As shown, the primary ammonia capture device includes: a first dust collector 6, a first injection point 5, a first pipeline 101, and a second pipeline 102. Specifically, the first injection point 5 is located upstream of the first dust collector 6. After the ammonia adsorbent is injected into the first injection point 5, it is dispersed and mixed with the flue gas in the pipeline. It reacts with ammonia through physical and chemical effects, so that ammonia molecules are adsorbed on the surface or inside of the ammonia adsorbent. The first injection point 5 is connected to the first dust collector 6 through the first pipeline 101. The flue gas, dust and ammonia adsorbent adsorbed with ammonia molecules enter the first dust collector 6 after passing through the first pipeline 101. The first dust collector 6 is connected to the first chimney 7 through the second pipeline 102. The flue gas that meets the emission standards after purification passes through the second pipeline 102 and is discharged through the first chimney 7. Further, in this embodiment, the ammonia adsorbent is a powdered ammonia adsorbent.

[0039] like Figure 1 As shown, in one embodiment of the present invention, the cement kiln ammonia removal and dust removal system includes a three-stage ammonia capture device. The first-stage ammonia capture device includes: a first dust collector 6, a first injection point 5, a first pipeline 101, and a second pipeline 102; the second-stage ammonia capture device includes: a second dust collector 61, a second injection point 51, and a first pipeline 101 and a second pipeline 102 respectively connected to both ends of the second dust collector 61; the third-stage ammonia capture device includes: a third dust collector 611, a third injection point 511, and a first pipeline 101 and a second pipeline 102 respectively connected to both ends of the third dust collector 611.

[0040] It should be noted that the working principles of the secondary ammonia capture device and the tertiary ammonia capture device are the same as the working principle of the primary ammonia capture device, so they will not be described in detail here.

[0041] In one embodiment of the present invention, a powdered ammonia adsorbent is provided in the first pipe 101 or the second pipe 102. Part of the ammonia in the flue gas at the injection point is adsorbed by the ammonia adsorbent. When the flue gas passes through the first pipe 101 and the second pipe 102, the mixed ammonia in the flue gas can be further adsorbed by the powdered ammonia adsorbent, so as to further reduce the ammonia content in the flue gas and make the discharged flue gas reach the standard range. Furthermore, in order to purify the flue gas more thoroughly, a powdered ammonia adsorbent can also be provided in both the first pipe 101 and the second pipe 102 to increase the adsorption rate of the ammonia adsorbent.

[0042] In one embodiment of the present invention, a block of ammonia adsorbent may be provided in the first pipe 101 and the second pipe 102. The block of ammonia adsorbent is a porous solid with a pore size ranging from 10 μm to 15 mm. The solid adsorbent may be formed by an adhesive and then supported by a stainless steel skeleton to form individual units, which are assembled together according to the required amount during installation.

[0043] The block ammonia adsorbent can be set in the first pipe 101 alone, can be set in the second pipe 102 alone, or can be set in the first pipe 101 and the second pipe 102 at the same time. It can be understood that the setting methods of the block ammonia adsorbent and the powdered ammonia adsorbent in the first pipe 101 and the second pipe 102 can be freely combined. For example, only the powdered ammonia adsorbent is set in the first pipe 101, or only the block ammonia adsorbent is set in the first pipe 101, or the powdered ammonia adsorbent is set in the first pipe 101 and the block ammonia adsorbent is set in the second pipe 102, etc. There are many ways to set it up, all of which are within the setting scope of the present invention, and they are not listed one by one here.

[0044] In one embodiment of the present invention, Figure 3 As shown, the block ammonia adsorbent can be assembled into a reactor 20, and then the reactor 20 can be installed on the first pipe 101. 1-10 blocks of ammonia adsorbent can be installed in the reactor 20, and different catalysts can be selected according to the concentration of ammonia. After working for a certain period of time, the ammonia adsorbent in the reactor 20 will reach saturation, or the adsorption rate of ammonia molecules will decrease. At this time, the bypass pipe 104 can be opened to allow the flue gas to no longer pass through the reactor 20, thereby replacing the ammonia adsorbent in the reactor 20 to ensure the adsorption rate of ammonia molecules in the flue gas and make the flue gas emissions meet the standards. The replaced block ammonia adsorbent can also be recycled, and its main recycling methods include: adding to the decomposition furnace, the combustion of the ammonia adsorbent can provide heat, and the ammonia can be used as a denitrification agent; through heating and analysis, the ammonia adsorbent can be reused, and the ammonia can be passed into the decomposition furnace alone for denitrification.

[0045] In one embodiment of the present invention, Figure 4 As shown, the reactor 20 can also be installed on the second pipe 102. Its working principle is the same as that of the reactor 20 installed on the first pipe 101, so it will not be repeated here. It can be understood that in order to enhance the adsorption rate of ammonia molecules, the reactor 20 can also be installed on the first pipe 101 and the second pipe 102 at the same time.

[0046] Furthermore, the block ammonia adsorbent in the reactor 20 can be in various shapes such as a rectangular parallelepiped, a cube, or a sheet with a cross-sectional shape of an original shape or an elliptical shape. In one embodiment of the present invention, the block ammonia adsorbent in the reactor 20 is a rectangular parallelepiped.

[0047] In one embodiment of the present invention, the cement kiln ammonia removal and dust removal system further includes an ammonia capture and conveying device, which is connected to the injection point to convey the powdered ammonia adsorbent to the injection point through the third pipeline 103.

[0048] Specifically, the ammonia capture and conveying device includes: a silo 14, a material discharge meter 15, a conveying pipeline 16 and a blower 17. The silo 14 stores a powdered ammonia adsorbent, and the powdered ammonia adsorbent enters the conveying pipeline 16 after passing through the material discharge meter 15 connected to the silo 14. The blower 17 is connected to the conveying pipeline 16, and sprays the powdered ammonia adsorbent falling into the conveying pipeline 16 to the injection point through the third pipeline 103.

[0049] In one embodiment of the present invention, Figure 1 As shown, the cement kiln deamination and dust removal system has a total of three-stage ammonia capture devices, a total of three injection points, namely the first injection point 5, the second injection point 51, and the third injection point 511. Each injection point is connected to the conveying pipeline 16 through the third pipeline 103, so that the powdered ammonia adsorbent is respectively sprayed to the first injection point 5, the second injection point 51 and the third injection point 511, so as to perform multi-stage adsorption of ammonia molecules in the cement kiln deamination and dust removal system. Furthermore, a valve 18 is provided on each third pipeline 103, and the injection position of the powdered ammonia adsorbent can be adjusted by switching the valve 18. For example, if the valve 18 on the third pipeline 103 connected to the three-stage ammonia capture device is closed, the powdered ammonia adsorbent will only be sprayed into the first injection point 5 and the second injection point 51, and will not be sprayed into the third injection point 511.

[0050] In one embodiment of the present invention, the cement kiln deammonification and dust removal system further includes a return ash conveying device 8, a raw material homogenization bin 13 and a closed housing 9. Specifically, the return ash conveying device 8 is connected to the first dust collector 6 to convey the powdered ammonia adsorbent and dust adsorbed with ammonia molecules passing through the first dust collector 6 to the raw material homogenization bin 13, and the tops of the raw material homogenization bin 13 and the return ash conveying device 8 are both provided with a closed housing 9.

[0051] Further, in one embodiment of the present invention, Figure 1As shown, dust and powdered ammonia adsorbent adsorbed with ammonia molecules enter the ash return conveying device 8 after passing through the first dust collector 6. A closed shell 9 is provided above the ash return conveying device 8 to prevent ammonia from leaking into the air. A small amount of dust will be lost during the conveying process, and a small amount of ammonia will be mixed in the lost dust. This part of the dust will enter the second dust collector 61 after ammonia molecules are adsorbed through the second injection point 51. The first discharge pipe 81 is arranged corresponding to the second dust collector 61, and the second dust collector 61 is connected to the first discharge pipe 81. The flue gas that meets the emission standards after adsorption and purification is discharged from the second chimney 71. The dust and powdered ammonia adsorbent adsorbed with ammonia molecules enter the ash return conveying device 8 after passing through the first discharge pipe 81, and enter the raw material homogenization warehouse 13 after being lifted by the first elevator 11.

[0052] The second feed pipe 811 is arranged corresponding to the third dust collector 611, and the second feed pipe 811 is connected to the raw material homogenization bin 13. Specifically, a small amount of ammonia is mixed in the dust lost in the raw material homogenization bin 13. After the ammonia is adsorbed by the powdered ammonia adsorbent in the third injection point 511 in the three-stage ammonia capture device, the flue gas that meets the emission standard is discharged from the third chimney 711, and the powdered ammonia adsorbent adsorbed with ammonia molecules and the dust enter the second feed pipe 811, and then enter the raw material homogenization bin 13.

[0053] Furthermore, the dust and powdered ammonia adsorbent that pass through the second dust collector 61 and enter the first discharge pipe 81 can also directly enter the raw material homogenization tank 13, be mixed with the raw material and then enter the preheater 2; or directly enter the preheater 2 to separate the ammonia and the ammonia adsorbent, and then reuse the ammonia.

[0054] Similarly, the dust and powdered ammonia adsorbent after dust removal by the third dust collector 611 can also directly enter the preheater 2 to separate the ammonia from the ammonia adsorbent, and then the ammonia can be reused.

[0055] More specifically, the preheater 2 includes a five-stage cyclone and a decomposition furnace, and the temperature inside the cyclone is different from that inside the decomposition furnace. The ammonia adsorbent can directly enter the cyclone or directly enter the decomposition furnace. Specifically, when the ammonia adsorbent directly enters the decomposition furnace, the temperature inside the decomposition furnace is 850-1000°C, and the ammonia in the ammonia adsorbent is released, which reacts with nitrogen oxides to perform denitrification treatment, thereby realizing the secondary utilization of ammonia; when the ammonia adsorbent enters the first-stage cyclone, the temperature inside the first-stage cyclone is 280-350°C, and the ammonia in the ammonia adsorbent is released, reacts with SO2, and plays a role in desulfurization, thereby realizing the secondary utilization of ammonia.

[0056] Reference Figure 1In one embodiment of the present invention, the cement kiln deammonification and dust removal system further includes an elevator. Specifically, the elevator includes a first elevator 11 and a second elevator 12. The first end of the first elevator 11 is connected to the ash return conveying device 8, and the second end of the first elevator 11 is connected to the raw material homogenization bin 13 to lift the dust and the powdered ammonia adsorbent adsorbed with ammonia molecules into the raw material homogenization bin 13. The first end of the second elevator 12 is connected to the outlet of the raw material homogenization bin 13, and the second end of the second elevator 12 is connected to the inlet of the preheater 2 to lift the powdered ammonia adsorbent adsorbed with ammonia molecules and the ground raw material into the preheater 2.

[0057] Continue to refer to Figure 1 In one embodiment of the present invention, the cement kiln deammonification and dust removal system also includes a rotary kiln 1, a raw mill device 3 and a humidifying tower device 4. Specifically, the rotary kiln 1 is connected to the preheater 2 to prepare cement. The raw mill device 3 is used to grind the raw materials for cement preparation into powder, and the ground raw materials enter the raw material homogenization reservoir 13, and enter the preheater 2 together with the powdered ammonia adsorbent adsorbed with ammonia molecules for preheating, thereby realizing the separation and secondary utilization of ammonia. Furthermore, the raw mill device 3 and the humidifying tower device 4 are arranged in parallel, and their inlets are connected to the outlet of the preheater 2, and their outlets are connected to the injection point 5, so that the flue gas mixed with ammonia generated in the cement preparation process is adsorbed by the powdered ammonia adsorbent at the first injection point 5 after passing through the raw mill device 3 and the humidifying tower device 4.

[0058] Continue to refer to Figure 1 In one embodiment of the present invention, the cement kiln deammonification and dust removal system further includes a plurality of chimneys. Specifically, each chimney is arranged corresponding to the dust collector, and the flue gas is adsorbed by the ammonia adsorbent arranged at the injection point, the ammonia adsorbent arranged in the first pipeline 101 and / or the second pipeline 102, and the flue gas that meets the emission standards after dust removal by the dust collector is discharged from the chimney.

[0059] The embodiment of the present invention also provides a method for removing ammonia and dust using a cement kiln deamination and dust removal system. Specifically, the method comprises the following steps:

[0060] The raw materials are prepared in the raw material mill 3, and the prepared powdered raw materials enter the raw material homogenization bin 13, and then are sent to the preheater 2 and the rotary kiln 1 to burn cement.

[0061] The flue gas and dust mixed with ammonia generated in the cement preparation process are subjected to ammonia molecule adsorption and dust removal in the primary ammonia capture device, and the powdered ammonia adsorbent adsorbed with ammonia molecules and part of the dust and ammonia lost during the transportation process enter the secondary ammonia capture device for ammonia molecule adsorption and dust removal. The ammonia adsorbent adsorbed with ammonia molecules and the dust are lifted by the first elevator 11 and then enter the raw material homogenization bin 13.

[0062] Specifically, after the ammonia molecules are adsorbed and dust-removed by the secondary ammonia capture device, the ammonia adsorbent adsorbed with ammonia molecules can directly enter the ash return conveying device 8 and enter the raw material homogenization bin 13 together with the ammonia adsorbent that has been adsorbed and dust-removed by the primary ammonia capture device after being lifted by the first elevator 11; it can also directly enter the raw material homogenization bin 13; it can also directly enter the preheater 2 to realize the separation of ammonia and the ammonia adsorbent, and then the ammonia is reused.

[0063] Furthermore, each stage of the ammonia capture device is also provided with a reactor 20, which is provided on the first pipeline 101 and / or the second pipeline 102, and a block ammonia adsorbent is provided in the reactor 20. After working for a certain period of time, the ammonia adsorbent in the reactor 20 will reach saturation, or the adsorption rate of ammonia molecules will decrease. At this time, the bypass pipeline 104 can be opened to allow the flue gas to no longer pass through the reactor 20, thereby replacing the ammonia adsorbent in the reactor 20 to ensure the adsorption rate of ammonia molecules in the flue gas and make the flue gas emissions meet the standards. The replaced block ammonia adsorbent can also be recycled, and its main recycling methods include: adding to the decomposition furnace, the combustion of the ammonia adsorbent can provide heat, and the ammonia can be used as a denitrification agent; through heating and analysis, the ammonia adsorbent can be reused, and the ammonia can be passed into the decomposition furnace alone for denitrification treatment.

[0064] The flue gas that meets the emission standards after being adsorbed by ammonia molecules at each stage is discharged from the chimneys corresponding to the ammonia capture devices at each stage. Part of the dust and ammonia lost in the raw material homogenization bin 13 is subjected to ammonia molecule adsorption in the three-stage ammonia capture device. The ammonia adsorbent and dust adsorbed with ammonia molecules enter the raw material homogenization bin 13, and are lifted by the second elevator 12 together with the powdered raw material and enter the preheater 2 to separate the ammonia adsorbent from the ammonia molecules so that the ammonia can be reused for the second time.

[0065] Specifically, after the ammonia molecules are adsorbed by the three-stage ammonia capture device, the ammonia adsorbent can directly enter the raw material homogenization tank 13 or directly enter the preheater 2.

[0066] Furthermore, the preheater 2 includes a five-stage cyclone and a decomposition furnace, and the temperature in the cyclone is different from that in the decomposition furnace. The ammonia adsorbent can directly enter the cyclone or directly enter the decomposition furnace. Specifically, when the ammonia adsorbent directly enters the decomposition furnace, the temperature in the decomposition furnace is 850-1000°C, and the ammonia in the ammonia adsorbent is released, which reacts with nitrogen oxides to perform denitrification treatment, thereby realizing the secondary utilization of ammonia; when the ammonia adsorbent enters the first-stage cyclone, the temperature in the first-stage cyclone is 280-350°C, and the ammonia in the ammonia adsorbent is released, reacts with SO2, and plays a role in desulfurization, thereby performing secondary utilization of ammonia.

[0067] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cement kiln deamination and dust removal system, characterized in that: include: A multi-stage ammonia capture device, wherein each stage of the ammonia capture device is provided with an ammonia adsorbent, and the ammonia adsorbent can adsorb ammonia molecules in the flue gas on the surface or inside of the ammonia adsorbent; A preheater is connected to the multi-stage ammonia capture device, wherein the preheater includes a cyclone and a decomposition furnace, the temperature in the cyclone is lower than the temperature in the decomposition furnace, and the decomposition furnace and the cyclone are both used to heat the ammonia adsorbent to release the ammonia in the ammonia adsorbent to react with nitrogen oxides in the decomposition furnace to perform denitrification treatment, or react with sulfur dioxide in the cyclone to achieve a desulfurization effect.

2. The cement kiln deamination and dust removal system according to claim 1, characterized in that: Each stage of the ammonia capture device comprises: A dust collector, wherein two ends of the dust collector are respectively connected to a first pipeline and a second pipeline; An injection point, the injection point being located upstream of the dust collector and used for injecting a powdered ammonia adsorbent to adsorb ammonia molecules in the flue gas; Wherein, the first pipeline is connected to the injection point, and the second pipeline is connected to the chimney.

3. The cement kiln deamination and dust removal system according to claim 2, characterized in that: A powdered ammonia adsorbent is disposed in at least one of the first pipe and the second pipe.

4. The cement kiln deamination and dust removal system according to claim 2, characterized in that: A reactor is disposed on at least one of the first pipe and the second pipe, and a block-shaped ammonia adsorbent is disposed in the reactor.

5. The cement kiln deamination and dust removal system according to claim 2, characterized in that: Also includes: an ammonia capture and delivery device, the ammonia capture and delivery device being connected to the injection point to deliver a powdered ammonia adsorbent to the injection point through a third pipeline; Wherein, the ammonia capture and transportation device comprises: A silo, the lower part of which is connected with a material discharge meter; A conveying pipeline, wherein the conveying pipeline is connected to the material discharge meter; A blower, the blower is connected to the conveying pipeline to spray the powdered ammonia adsorbent in the silo to the injection point via the feed meter, the conveying pipeline and the third pipeline; Wherein, a valve is arranged on the third pipeline to adjust the injection position of the injection point.

6. The cement kiln deammoniation and dust removal system according to claim 1, characterized in that: It also includes a return ash conveying device, a raw material homogenizing silo and a closed shell. The return ash conveying device is connected to the first dust collector to convey the powdered ammonia adsorbent and dust passing through the first dust collector to the raw material homogenizing silo. Wherein, the sealed casing is respectively provided on the top of the first dust collector and the top of the raw material homogenizing bin.

7. The cement kiln deammoniation and dust removal system according to claim 6, characterized in that: Also includes: A first feeding pipe and a second feeding pipe, wherein the first feeding pipe and the second feeding pipe are respectively arranged corresponding to the second dust collector and the third dust collector, Wherein, the first feed pipe is connected to the ash return conveying device, and the second feed pipe is connected to the raw material homogenizing storage.

8. The cement kiln deammoniation and dust removal system according to claim 6, characterized in that: Also included is a hoist, the hoist comprising: A first elevator, wherein a first end of the first elevator is connected to the ash return conveying device, and a second end of the first elevator is connected to a raw material homogenizing silo; A second elevator, wherein a first end of the second elevator is connected to the outlet of the raw material homogenization storage, and a second end of the second elevator is connected to the inlet of the preheater.

9. The cement kiln deamination and dust removal system according to claim 2, characterized in that: Also includes: A rotary kiln, wherein the rotary kiln is connected to the preheater; A raw mill device, wherein the inlet of the raw mill device is connected to the outlet of the preheater, and the outlet of the raw mill device is connected to the inlet of the ammonia capture device; A humidifying tower device, wherein the humidifying tower device is arranged in parallel with the raw material mill device, and the inlet of the humidifying tower device is connected to the outlet of the preheater, and the outlet of the humidifying tower device is connected to the inlet of the ammonia capture device; There are multiple chimneys, each of which is arranged corresponding to the dust collector and connected to the dust collector.

10. A method for deamination and dust removal using the cement kiln deamination and dust removal system according to any one of claims 1 to 9, characterized in that: include: The raw materials are prepared in the raw mill, and the prepared powdered raw materials enter the raw material homogenization silo, and then are sent to the preheater and rotary kiln to burn cement; The smoke and dust generated in the cement preparation process are subjected to ammonia molecule adsorption and dust removal in the primary ammonia capture device, and the powdered ammonia adsorbent adsorbed with ammonia molecules and part of the dust and ammonia lost during the dust transportation process enter the secondary ammonia capture device for ammonia molecule adsorption and dust removal, and the ammonia adsorbent adsorbed with ammonia molecules and the dust are lifted and then enter the raw material homogenization silo; The flue gas after the adsorption of ammonia molecules at each stage is discharged from the chimney corresponding to the ammonia capture device. Part of the dust and ammonia lost in the raw material homogenization warehouse is subjected to ammonia molecule adsorption in the three-stage ammonia capture device. The ammonia adsorbent and dust adsorbed with ammonia molecules enter the raw material homogenization warehouse, and enter the preheater together with the powdered raw material through lifting, so as to realize the separation of the ammonia adsorbent and the ammonia molecules, so as to make secondary use of the ammonia.

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