A Uniform Flow Guiding System for SCR Denitration Reactor Tower

Abstract

The present invention discloses a uniform flow guiding system for an SCR denitration reaction tower, which is characterized in that: a plurality of flow guiding layers are provided at the inlet end of the reaction tower. The flow guiding layers are respectively the first flow guiding and uniform distribution layer, the second flow guiding and uniform distribution layer, and the third flow guiding and uniform distribution layer from top to bottom. Second flow guiding plates and third flow guiding plates arranged vertically are respectively provided on the second flow guiding and uniform distribution layer and the third flow guiding and uniform distribution layer. The uniform flow guiding system for the SCR denitration reaction tower of the present invention has a simple structure and reasonable layout, can effectively distribute the gas, enable the gas to uniformly pass through the catalyst, improve the SCR denitration reaction efficiency, and has strong practicability and good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of SCR denitration in a cement clinker production line, and more specifically, relates to a uniform flow guiding system for an SCR denitration reaction tower. Background Art

[0002] (1) Clinker production process:

[0003] The materials prepared in a certain proportion are fed into the top of the preheater, preheated by the cyclone preheater and then enter the decomposition furnace, where they are decomposed and then enter the rotary kiln for calcination, and then enter the grate cooler for cooling, and finally the required clinker is obtained.

[0004] (2) Background of denitration technology for cement production lines

[0005] Cement is an important pillar industry of the national economy. Due to the need of economic development, the total output of the Chinese cement industry has shown a rapid growth trend in the past two decades. As of the end of 2019, there were more than 1,600 new dry-process cement production lines nationwide, and the cement production capacity was 2.33 billion tons.

[0006] The process of urbanization and rapid economic development is inseparable from the contribution of the cement industry, but at the same time, it also brings environmental problems that cannot be ignored. Since fuel combustion is required to provide the heat for the formation of clinker minerals in cement clinker production, a certain amount of nitrogen oxides will be generated during this process. Therefore, the state and local governments have promulgated a series of laws and regulations to limit the emission of NOx.

[0007] According to the existing regulations, the NOx emission concentration in general areas is controlled at ≤400 mg / Nm3, and in key areas, it is controlled at ≤320 mg / Nm3. Moreover, local environmental protection departments of local governments have also promulgated local regulations and laws to strictly control pollutant emissions. For example, regions such as Jiangsu, Shandong, Henan, and Zhejiang will implement the control index requirement of 100 mg / Nm3. In order to control pollution, peak-shifting production is implemented in regions such as Shandong, Hebei, Shaanxi, Shanxi, Anhui, Jiangsu, and Zhejiang.

[0008] At present, the most widely used denitration technologies in the cement industry are mainly staged combustion and selective non-catalytic reduction denitration (SNCR denitration). Among them, staged combustion is a front-end control method with no operating cost, but the denitration efficiency is low, only about 40%. As a measure to further reduce the NOx emission concentration, the SNCR denitration method has been widely used in the cement industry due to its simple system process and low investment. However, this method has problems such as low ammonia utilization efficiency, large ammonia consumption, high ammonia slip, corrosion of pipelines and equipment, etc.

[0009] When the NOx emission concentration is further tightened and the ammonia slip index is strictly controlled, the staged combustion and SNCR denitration technologies are difficult to meet the increasingly stringent NOx emission standards. The selective catalytic reduction technology (SCR denitration technology), relying on the catalytic reduction of highly active components, promotes the reaction of NH3 and NOx, and has the characteristics of high denitration efficiency (above 95%) and high ammonia water utilization rate.

[0010] In the SCR method, the reducing agent (NH3 or urea) selectively reacts with NOx to form N2 and H2O under the action of a catalyst, rather than being oxidized by O2, so it is called "selective". The main reactions are as follows:

[0011] Ammonia

[0012]

[0013] Urea

[0014] The schematic diagram of the denitration principle is shown in Figure 1 as follows.

[0015] The SCR reaction tower is one of the main equipment for SCR catalytic reduction denitration. It mainly includes an inlet uniform flow guiding device, a dust conveying device arranged at the bottom, the catalyst is arranged in the middle position, a dust cleaning device is arranged for each layer of the catalyst, and necessary equipment such as temperature and pressure instruments and maintenance platforms are provided. The flow direction of the waste gas has an important impact on denitration. In the prior art, there is a situation where the denitration efficiency is low due to uneven waste gas flow direction, which needs to be further improved. Summary of the Invention

[0016] The purpose of the present invention is to solve the problems existing in the prior art, and provide a SCR denitration reaction tower uniform flow guiding system with a simple structure, reasonable layout, which can effectively distribute the gas, make the gas pass through the catalyst evenly, and improve the SCR denitration reaction efficiency.

[0017] In order to achieve the above purpose, the technical solution adopted by the present invention is: the provided SCR denitration reaction tower uniform flow guiding system is characterized in that: a plurality of flow guiding layers are provided at the inlet end of the reaction tower, and the flow guiding layers are respectively the first flow guiding and uniform layer, the second flow guiding and uniform layer, and the third flow guiding and uniform layer from top to bottom. Second flow guiding plates and third flow guiding plates are vertically arranged on the second flow guiding and uniform layer and the third flow guiding and uniform layer respectively.

[0018] To make the above technical solution more detailed and specific, the present invention also provides the following further preferred technical solutions to obtain satisfactory practical effects:

[0019] The first flow guiding and uniform layer includes first transverse flow guiding plates and first longitudinal flow guiding plates arranged in a horizontal and vertical staggered manner.

[0020] The first transverse deflector plate takes the middle as the symmetry center, and the lower ends of the first transverse deflector plates on both sides incline towards both sides respectively; the first longitudinal deflector plate takes the middle as the symmetry center, and the lower ends of the first longitudinal deflector plates on both sides incline towards both sides respectively.

[0021] The second-layer deflector distribution layer includes second-layer support rods and second-layer deflector plates supported on the second-layer support rods.

[0022] The second-layer deflector plate is a V-shaped structural plate with an opening downward.

[0023] The second-layer deflector plate extends along the direction perpendicular to the second-layer support rod; a plurality of the second-layer deflector plates are arranged at intervals in the length direction of the second-layer support rod.

[0024] The third-layer deflector distribution layer includes third-layer support rods and third-layer deflector plates supported on the third-layer support rods.

[0025] The third-layer deflector plate is a V-shaped structural plate with an opening downward.

[0026] The third-layer deflector plate extends along the direction perpendicular to the third-layer support rod; a plurality of the third-layer deflector plates are arranged at intervals in the length direction of the third-layer support rod.

[0027] Edge opening deflector plates are provided at both edges of the third-layer deflector plate. The edge opening deflector plates are arranged parallel to the third-layer deflector plate. The edge opening deflector plates are V-shaped structural plates with an opening downward, and a deflector plate opening is provided at the upper end of the V-shaped structural plate.

[0028] Compared with the prior art, the present invention has the following advantages: The SCR denitration reaction tower uniform deflector system of the present invention has a simple structure and reasonable layout, can effectively distribute the gas, enable the gas to pass through the catalyst evenly, improve the SCR denitration reaction efficiency, and has strong practicability and good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The following briefly describes the content expressed by the drawings of this specification and the marks in the drawings:

[0030] Figure 1 It is a denitration principle diagram;

[0031] Figure 2 It is a schematic structural diagram of the reaction tower uniform deflector system of the present invention;

[0032] Figure 3 It is a schematic structural diagram of the reaction tower uniform deflector system of the present invention;

[0033] Figure 4Top view of the first layer flow guiding and distributing layer of the present invention;

[0034] Figure 5 Front view of the first layer flow guiding and distributing layer of the present invention

[0035] Figure 6 Top view of the second layer flow guiding and distributing layer of the present invention;

[0036] Figure 7 Front view of the second layer flow guiding and distributing layer of the present invention;

[0037] Figure 8 is Figure 7 Schematic enlarged structure diagram of A in

[0038] Figure 9 Top view of the third layer flow guiding and distributing layer of the present invention;

[0039] Figure 10 Front view of the third layer flow guiding and distributing layer of the present invention;

[0040] Figure 11 is Figure 10 Schematic enlarged structure diagram of B in

[0041] Figure 12 is Figure 10 Schematic enlarged structure diagram of C in

[0042] The markings in the figure are: 1, inlet end; 2, the first layer flow guiding and distributing layer; 21, the first transverse flow guiding plate; 22, the first longitudinal flow guiding plate; 3, the second layer flow guiding and distributing layer; 31, the second layer support rod; 32, the second layer flow guiding plate; 4, the third layer flow guiding and distributing layer; 41, the third layer support rod; 42, the third layer flow guiding plate; 43, the edge opening flow guiding plate; 44, the flow guiding plate opening. Detailed implementation manners

[0043] The following further describes in detail the specific implementation manners of the present invention by describing the embodiments with reference to the accompanying drawings.

[0044] This SCR denitration reaction tower uniform flow guiding system of the present invention, as shown in Figure 2 , 3 , is provided with multiple layers of flow guiding layers at the inlet end 1 of the reaction tower. The flow guiding layers are, from top to bottom, the first layer flow guiding and distributing layer 2, the second layer flow guiding and distributing layer 3, and the third layer flow guiding and distributing layer 4. The second layer flow guiding and distributing layer 3 and the third layer flow guiding and distributing layer 4 are respectively provided with vertically arranged second layer flow guiding plates 32 and third layer flow guiding plates 42.

[0045] In the present invention, as shown in Figure 4 , 5As shown in the figure, the first-layer flow guiding and distributing layer 2 includes a first transverse flow guiding plate 21 and a first longitudinal flow guiding plate 22 which are arranged in a crisscross manner. The first transverse flow guiding plate 21 takes the middle as the symmetry center, and the lower ends of the first transverse flow guiding plates 21 on both sides incline towards both sides respectively; the first longitudinal flow guiding plate 22 takes the middle as the symmetry center, and the lower ends of the first longitudinal flow guiding plates 22 on both sides incline towards both sides respectively. In this embodiment, the first-layer flow guiding and distributing layer 2 is provided with three first transverse flow guiding plates 21 and three first longitudinal flow guiding plates 22. The first transverse flow guiding plate 21 and the first longitudinal flow guiding plate 22 at the middle position are arranged vertically, and the lower ends of the first transverse flow guiding plates 21 and the first longitudinal flow guiding plates 22 on both sides incline towards the outside, forming a flow guiding structure with a small upper opening and a large lower opening, and smoothly guiding the waste gas in the inlet section to both sides.

[0046] In the present invention, as Figure 6 , 7 , 8 shown, the second-layer flow guiding and distributing layer 3 includes a second-layer support rod 31 and a second-layer flow guiding plate 32 supported on the second-layer support rod 31. The second-layer flow guiding plate 32 is a V-shaped structural plate with an opening downward. The second-layer flow guiding plate 32 extends along the direction perpendicular to the second-layer support rod 31; a plurality of second-layer flow guiding plates 32 are arranged at intervals in the length direction of the second-layer support rod 31. A plurality of support rods arranged at intervals can be arranged below the second-layer flow guiding plate 32 according to the support needs. The waste gas guided by the first-layer flow guiding and distributing layer passes through the second-layer flow guiding and distributing layer 3, and evenly guides the gas along the guiding surface of the second-layer flow guiding plate 32 to the lower part.

[0047] In the present invention, as Figure 9 , 10 , 11, 12 shown, the third-layer flow guiding and distributing layer 4 includes a third-layer support rod 41 and a third-layer flow guiding plate 42 supported on the third-layer support rod 41. The third-layer flow guiding plate 42 is a V-shaped structural plate with an opening downward. The third-layer flow guiding plate 42 extends along the direction perpendicular to the third-layer support rod 41; a plurality of third-layer flow guiding plates 42 are arranged at intervals in the length direction of the third-layer support rod 41. A plurality of support rods arranged at intervals can be arranged below the third-layer flow guiding plate 42 according to the support needs. The third-layer flow guiding plate 42 and the second-layer flow guiding plate 32 are arranged perpendicularly to completely evenly guide and distribute the waste gas at the inlet end of the reaction tower, and improve the denitration efficiency.

[0048] In the present invention, as Figure 12As shown in the figure, edge opening deflectors 43 are provided on both side edges of the third-layer deflector 42. The edge opening deflectors 43 are arranged parallel to the third-layer deflector 42. The edge opening deflectors 43 are V-shaped structural plates with the opening facing downwards. A deflector opening 44 is provided at the upper end of the V-shaped structural plate. Through flow monitoring and observation, below the inlet end, the area is relatively large, and the gas flow at both side edges is limited. By setting the edge opening deflectors 43, that is, deflecting the deflector opening 44 on the third-layer deflector 42, the gas flow at the edge position can be increased to achieve uniform diversion.

[0049] In the present invention, arc chamfers with a radius R of 1 mm - 8 mm are provided at the upper ends of the second-layer deflector 32 and the third-layer deflector 42 to improve the diversion effect and facilitate manufacturing and forming.

[0050] The present invention deeply analyzes the current waste gas situation in the cement kiln production line, adds a diversion and uniform distribution device at the inlet position of the SCR reaction tower, changes the flow direction of the waste gas, makes the waste gas concentration entering the catalyst tend to be uniform, and ensures the SCR denitration efficiency.

[0051] The present invention belongs to a gas flow uniform diversion device for an SCR denitration technology reaction tower in a new dry-process cement clinker production line. The uniformity of the gas in the SCR reaction tower is an important index in the design of the reaction tower, which is related to the denitration efficiency and the long-term stability of the operation of the SCR system. Installing the diversion and uniform distribution device of the present invention at the inlet of the SCR reaction tower can effectively distribute the gas, making the gas pass through the catalyst evenly, thereby ensuring the SCR denitration reaction efficiency.

[0052] A diversion and uniform distribution device is installed at the inlet of the SCR reaction tower, mainly including a first-layer diversion and uniform distribution layer 2, a second-layer diversion and uniform distribution layer 3, and a third-layer diversion and uniform distribution layer 4. The three layers are arranged at a certain interval. The first layer realizes downward guiding and diversion, and the second and third layers respectively divert to both sides. Through the deflectors evenly arranged between the layers, the gas is effectively diverted and distributed, playing a good role in guiding and evenly distributing the gas.

[0053] In this embodiment, the first-layer diversion and uniform distribution plate is mainly made of flat steel with a height of 200 - 500 mm and a thickness of 8 - 15 mm. Three deflectors are arranged both horizontally and vertically. The deflector in the middle position follows the direction of the waste gas and is arranged at 90° to the horizontal plane. The deflectors on both sides are symmetrically arranged with a spacing of 800 - 1200 mm and an included angle of 55 - 75° with the horizontal plane.

[0054] In this embodiment, the second-layer deflector 32 is made of a steel plate with a height of 120 - 200 mm and a thickness of 8 - 15 mm. Its shape is like an inverted "V". The span of a single deflector is 60 - 80 mm, the spacing between two deflectors is 100 - 200 mm, and the top end of the deflector is an arc chamfer with a radius of 1 mm - 8 mm.

[0055] In this embodiment, the third-layer flow deflector 42 is made of a steel plate with a height of 120-200 mm and a thickness of 8-15 mm. It is shaped like an inverted "V", with a single flow deflector having a span of 60-80 mm and a spacing of 100-200 mm between two flow deflectors. The top of the flow deflector has an arc chamfer with a radius of 1 mm-8 mm. At both ends of the entire third layer, there are 3 to 4 rows of open inverted "V"-shaped flow deflectors, namely edge open flow deflectors 43, and the width of the flow deflector opening 44 is 4-12 mm. After passing through the three-layer flow distribution device, the waste gas can pass through the catalyst more evenly, ensuring good denitration efficiency of SCR.

[0056] The SCR denitration reaction tower flow distribution and diversion system of the present invention has a simple structure and reasonable layout. It can effectively distribute the gas, enable the gas to pass through the catalyst evenly, improve the SCR denitration reaction efficiency, and has strong practicability and good application prospects.

[0057] The present invention has been described exemplarily above in conjunction with the accompanying drawings. However, the present invention is not limited to the above manner. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention or directly applied to other occasions, they all fall within the protection scope of the present invention.

Claims

1. A uniform flow guiding system for an SCR denitration reaction tower, characterized in that: A multi-layer diversion layer is provided at the inlet end of the reaction tower. The diversion layer includes a first diversion uniform distribution layer, a second diversion uniform distribution layer, and a third diversion uniform distribution layer from top to bottom. The second diversion uniform distribution layer and the third diversion uniform distribution layer are respectively provided with a second diversion plate and a third diversion plate arranged vertically. The first diversion uniform distribution layer includes a first transverse diversion plate and a first longitudinal diversion plate arranged in a horizontal and vertical staggered manner. The first transverse diversion plate takes the middle as the symmetry center, and the lower ends of the first transverse diversion plates on both sides are respectively inclined towards both sides. The first longitudinal diversion plate takes the middle as the symmetry center, and the lower ends of the first longitudinal diversion plates on both sides are respectively inclined towards both sides. The second diversion uniform distribution layer includes a second support rod and a second diversion plate supported on the second support rod. The second diversion plate is a V-shaped structure plate with an opening downward. The second diversion plate extends in a direction perpendicular to the second support rod. A plurality of the second diversion plates are arranged at intervals in the length direction of the second support rod. The third diversion uniform distribution layer includes a third support rod and a third diversion plate supported on the third support rod. The third diversion plate is a V-shaped structure plate with an opening downward. The third diversion plate extends in a direction perpendicular to the third support rod. A plurality of the third diversion plates are arranged at intervals in the length direction of the third support rod. Edge opening diversion plates are provided at both side edges of the third diversion uniform distribution layer. The edge opening diversion plates are arranged parallel to the third diversion plate. The edge opening diversion plates are V-shaped structure plates with an opening downward. A diversion plate opening is provided at the upper end of the V-shaped structure plate.

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