SCR (Selective Catalytic Reduction) denitration process system
By introducing high-temperature electrostatic dust collectors and soot blowers into the SCR denitrification system, the problem of traditional systems being susceptible to dust clogging is solved, the service life of the catalyst is extended, and the denitrification efficiency and system maintenance are improved.
Patent Information
- Application Number
- CN202421812496.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-30
- Publication Date
- 2025-04-18
- Estimated Expiration
- 2034-07-30
AI Technical Summary
Traditional SCR denitrification systems are susceptible to dust blockage, which affects the service life of the catalyst and is inconvenient to maintain, have low denitrification efficiency, high cost and short service life.
A SCR denitrification process system is designed, including high-temperature electrostatic precipitator, rake and sonic blower, detachable catalyst layer and heat exchanger. Dust is removed through high-temperature electrostatic precipitator, and the rake and sonic blower are treated with the catalyst layer to improve the mechanical and chemical life of the catalyst.
Effectively remove dust in the flue gas, extend the service life of the catalyst, improve denitrification efficiency, reduce usage costs, and facilitate maintenance and maintenance of the catalyst layer.
Smart Images
Figure CN222766485U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of SCR denitration of cement kilns, in particular to an SCR denitration process system. Background Art
[0002] Due to the high temperature conditions and special chemical reactions in the kiln during cement production, a large amount of NOx is produced, so measures need to be taken to reduce the emission of these harmful substances.
[0003] In the prior art, one of the commonly used denitrification technologies in cement kilns is selective catalytic reduction, namely the SCR system. The use of the SCR system can make the emission of NOx (nitrogen oxides) meet the standards. However, the traditional SCR system is easily clogged by dust, which affects the service life of the catalyst. At the same time, after long-term use, it is not convenient to maintain and repair the catalyst layer, and the heat generated in the denitrification process is not reused. Therefore, the denitrification efficiency is low, the cost of use is high, and the service life is short. Utility Model Content
[0004] In order to solve the above technical problems, the utility model provides an SCR denitration process system to increase the service life of the catalyst.
[0005] To achieve the above objectives, the utility model is implemented through the following technical solutions: an SCR denitration process system, including a cement kiln main body, characterized in that an SP boiler and a high-temperature electrostatic precipitator are arranged on one side of the cement kiln main body, an ammonia metering and injection system is arranged on the upper side of the high-temperature electrostatic precipitator, the high-temperature electrostatic precipitator is connected to the SCR denitration reactor through a flue, a catalyst layer is detachably installed inside the SCR denitration reactor from top to bottom, each catalyst layer is correspondingly provided with a rake soot blower and a sonic soot blower, the rake soot blower and the sonic soot blower are respectively located on opposite sides of the catalyst layer, a heat exchanger is arranged on the bottom side of the SCR denitration reactor, the ammonia metering and injection system and the sonic soot blower are connected to the exhaust pipe of a compressed air system, the exhaust pipe of the compressed air system is also connected to the cold side inlet of the heat exchanger, the hot side outlet of the heat exchanger is connected to the air inlet of the rake soot blower, and the ammonia metering and injection system is connected to an ammonia delivery system.
[0006] In the above scheme, four catalyst layers are arranged from top to bottom in the SCR denitration reactor.
[0007] In the above scheme, an ash conveying system is provided at the lower side of the high-temperature electrostatic precipitator and the SCR denitration reactor, and the lower ash hoppers of the high-temperature electrostatic precipitator and the SCR denitration reactor are connected to the ash conveying system.
[0008] In the above solution, a high-temperature fan is connected to the bottom of the SP boiler.
[0009] In the above scheme, the SP boiler is connected to the cement kiln body and the exhaust port of the SCR denitration reactor through pipelines, and control valves are evenly arranged on the pipelines.
[0010] The utility model provides an SCR denitration process system, which has the following beneficial effects:
[0011] High-temperature electrostatic precipitator can remove dust from flue gas, solve the problem of high dust content in cement kiln tail flue gas, and improve the mechanical and chemical life of catalyst. Through the combination of rake soot blower and sonic soot blower, each catalyst layer surface can be further soot-blown to avoid dead corners in the catalyst layer, which may cause catalyst failure and reduce denitrification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a schematic diagram of the main structure of the utility model.
[0013] Figure 2 The utility model is a schematic diagram of the structure of the ammonia water metering and injection system.
[0014] Figure 3 This is a schematic diagram of the structure of the ammonia water delivery system of the utility model.
[0015] Figure 4 This is the PID diagram of the rake sootblower system of the utility model.
[0016] Figure 5 This is the PID diagram of the sonic soot blower system of the utility model.
[0017] In the figure: 1. Cement kiln body, 2. SP boiler, 3. High-temperature electrostatic precipitator, 4. Ammonia metering and injection system, 5. SCR denitrification reactor, 6. Rake soot blower, 7. Sonic soot blower, 8. Heat exchanger, 9. Compressed air system, 10. Ammonia delivery system, 11. Ash delivery system, 12. High-temperature fan. DETAILED DESCRIPTION
[0018] The utility model is further described below in conjunction with the accompanying drawings and embodiments.
[0019] Example 1
[0020] See also Figure 1-5A SCR denitration process system includes a cement kiln body 1, an SP boiler 2 is arranged on one side of the cement kiln body 1, a high-temperature electrostatic precipitator 3 is arranged on one side of the cement kiln body 1, an ammonia water metering and injection system 4 is arranged on the upper side of the high-temperature electrostatic precipitator 3, the high-temperature electrostatic precipitator 3 is connected to an SCR denitration reactor 5 through a flue, and a detachable catalyst layer is arranged inside the SCR denitration reactor 5 from top to bottom. Preferably, four catalyst layers are arranged inside the SCR denitration reactor from top to bottom, and the catalyst layers inside the SCR denitration reactor are all detachable. At the same time, a manhole is arranged at the front end of the catalyst layer to facilitate the inspection of the catalyst module inside the catalyst layer. Each catalyst layer is provided with a rake soot blower 6 and a sonic soot blower 7, which are respectively located on opposite sides of the catalyst layer. A heat exchanger 8 is provided at the bottom of the SCR denitration reactor 5. The ammonia metering and injection system 4 and the sonic soot blower 7 are connected to the exhaust pipe of the compressed air system 9, and the exhaust pipe of the compressed air system 9 is also connected to the cold side inlet of the heat exchanger 8. The hot side outlet of the heat exchanger 8 is connected to the air inlet of the rake soot blower. The ammonia metering and injection system 4 is connected to the ammonia delivery system 10.
[0021] An ash conveying system 11 is provided at the lower side of the high-temperature electrostatic precipitator and the SCR denitration reactor, and the lower ash hoppers of the high-temperature electrostatic precipitator and the SCR denitration reactor are connected to the ash conveying system 11. A high-temperature fan 12 is connected to the bottom of the SP boiler. The SP boiler is connected to the main body of the cement kiln and the exhaust port of the SCR denitration reactor through pipelines, and control valves are evenly arranged on the pipelines.
[0022] The structures of the rake soot blower and the sonic soot blower are both prior art and will not be described in detail here.
[0023] The ammonia delivery system 10 is a prior art, including an ammonia storage tank and an ammonia delivery pump. The reducing agent ammonia is transported to the factory by a tank truck and injected into the storage tank through a discharge pump station. The ammonia delivery pump (one for use and one for standby) provides ammonia to each line under a certain pressure. The amount of ammonia required for denitrification is controlled by a metering module flow regulating valve, and then the ammonia moves to the inside of the ammonia metering and injection system 4, as shown in FIG. Figure 2 The ammonia water metering and injection system 4 also includes a spray gun arranged circumferentially at the inlet of the high-temperature electrostatic precipitator 3. The spray gun is arranged circumferentially to ensure the uniformity of the injection. The spray gun adopts a dual-fluid spray gun. The reducing agent ammonia solution (SCR adopts an ammonia solution with a mass concentration of 20%) and the compressed air generated by the compressed air system 9 enter the spray gun respectively to ensure the atomization injection effect of the reducing agent. A flow meter is provided in the ammonia water branch pipeline in front of each spray gun to monitor the flow of the ammonia solution of the spray gun. The compressed air pipeline is provided with a filter pressure reducing valve to control the pressure of the compressed air so that the spray gun can achieve the best atomization effect.
[0024] The compressed air system 9 is a prior art and will not be described in detail here. It is mainly composed of a transformer, a pre-filter, a cold dryer, a post-filter and a compressed air storage tank. The air can be filtered, condensed and compressed, and respectively introduced into the sonic soot blower 7, the ammonia metering and injection system 4 and the heat exchanger 8.
[0025] The reduced flue gas enters the high-temperature electrostatic precipitator 3 for efficient dust removal operation. The dust-removed flue gas enters the SCR denitration reactor 5 for catalytic reaction. The reactor shell is a spatial structure containing the catalyst. It is mainly composed of a frame steel structure and steel plates welded to form a closed space. Q355B material is used. In order to prevent the heat dissipation of the flue gas, a thermal insulation interlayer is arranged on the SCR denitration reactor 5. The SCR denitration reactor 5 is installed on the steel frame and supported by steel beams and steel columns for reinforcement. Multiple layers of catalyst layers are arranged from top to bottom in the SCR denitration reactor 5. One side of the outer wall of the SCR denitration reactor 5 is provided with an inspection door at the catalyst layer for loading the catalyst module into the catalyst layer. Each catalyst layer is provided with a manhole, which allows entry to inspect the catalyst module when the unit is shut down. The flue gas is discharged from the top of the reactor and vertically to the bottom. The catalyst layer is fixed in the SCR denitrification reactor 5 by the steel beam supporting the catalyst module. The operation requirements of the catalyst and the operation, maintenance and overhaul of the denitrification device are met. In the flue gas catalysis process, in order to ensure that the catalyst does not break due to cold shock and the reduction of flue gas temperature, the compressed air entering the rake soot blower 6 needs to be heated to above 200°C by the heat exchanger 8. The technical solution adopts a special GGH heat exchanger 8 and an internal circulation method without additional energy consumption. The heated hot compressed air enters the rake soot blower 6 for mobile blowing to remove the dust accumulated inside the catalyst. At the same time, the sonic soot blower 7 can be used to further increase the soot blowing effect of the catalyst layer to avoid the situation where the catalyst fails due to dead corners in the catalyst layer, resulting in a decrease in the denitrification efficiency.
[0026] After the denitrification is completed, the flue gas after denitrification will be discharged through the lower side of the SCR denitrification reactor 5, and enter the SP boiler 2 through the pipeline and the control valve, so that the heat generated by the flue gas after denitrification can be recovered for subsequent utilization. At the same time, the high-temperature fan 12 can be controlled according to the use requirements to directly discharge the flue gas after denitrification. At the same time, the dust adsorbed by the high-temperature electrostatic precipitator 3 and the products after denitrification can be discharged to the ash conveying system 11 and transported through the ash conveying system 11 for subsequent processing.
[0027] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. An SCR denitrification process system, comprising a cement kiln main body, characterized in that: An SP boiler and a high-temperature electrostatic precipitator are arranged on one side of the cement kiln body, an ammonia metering and injection system is arranged on the upper side of the high-temperature electrostatic precipitator, the high-temperature electrostatic precipitator is connected to an SCR denitration reactor through a flue, a catalyst layer is detachably installed inside the SCR denitration reactor from top to bottom, each catalyst layer is correspondingly provided with a rake soot blower and a sonic soot blower, the rake soot blower and the sonic soot blower are respectively located on opposite sides of the catalyst layer, a heat exchanger is arranged on the bottom side of the SCR denitration reactor, the ammonia metering and injection system and the sonic soot blower are connected to the exhaust pipe of a compressed air system, the exhaust pipe of the compressed air system is also connected to the cold side inlet of the heat exchanger, the hot side outlet of the heat exchanger is connected to the air inlet of the rake soot blower, and the ammonia metering and injection system is connected to an ammonia delivery system.
2. The SCR denitration process system according to claim 1, characterized in that: The SCR denitration reactor is provided with four catalyst layers from top to bottom.
3. The SCR denitration process system according to claim 2, characterized in that: An ash conveying system is arranged at the lower side of the high-temperature electrostatic precipitator and the SCR denitration reactor, and the lower ash hoppers of the high-temperature electrostatic precipitator and the SCR denitration reactor are connected to the ash conveying system.
4. The SCR denitration process system according to claim 3, characterized in that: A high-temperature fan is connected to the bottom of the SP boiler.
5. The SCR denitration process system according to claim 4, characterized in that: The SP boiler is connected to the cement kiln body and the exhaust port of the SCR denitration reactor through pipelines, and control valves are evenly arranged on the pipelines.