SNCR (Selective Non-Catalytic Reduction) denitration environment-friendly system with stable operation, energy conservation and consumption reduction
Patent Information
- Application Number
- CN202421963903.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-14
- Publication Date
- 2025-07-18
- Estimated Expiration
- 2034-08-14
AI Technical Summary
[0003]如若氨水喷加量过大，NH3反应不完全，容易造成NH3逃逸，造成氨水的浪费，如若氨水喷加量过少，烟气中的N0x反应不完全，会使N0x排放量过大，在控制氨水喷加量时，氨水调节阀是一个重要的部件，通过控制系统控制氨水调节阀的阀门开度以控制氨水的喷射量，但是，现有的调节阀，其阀门开度与氨水流量为非线性关系，通过控制系统调节阀门开度不能准确的控制氨水流量，会造成氨水浪费或者N0x排放量超标的问题
Smart Images
Figure CN223112752U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of denitrification, and particularly to an SNCR denitrification environmental protection system for stable operation, energy conservation and consumption reduction. Background Art
[0002] The SNCR denitrification technology - also known as the selective non-catalytic reduction denitrification technology - is an end-treatment technology for flue gas NOx. It selectively reduces NOx in the flue gas to N2 and H2O by using a reducing agent (ammonia water) containing amino groups in the temperature range of 850°C - 1250°C, so as to achieve the purpose of NOx emission reduction.
[0003] If the ammonia water injection amount is too large, the NH3 reaction is incomplete, which is likely to cause NH3 escape and waste of ammonia water. If the ammonia water injection amount is too small, the NOx in the flue gas reacts incompletely, resulting in excessive NOx emissions. When controlling the ammonia water injection amount, the ammonia water regulating valve is an important component. The valve opening of the ammonia water regulating valve is controlled by a control system to control the injection amount of ammonia water. However, for existing regulating valves, the relationship between the valve opening and the ammonia water flow rate is non-linear. Adjusting the valve opening through the control system cannot accurately control the ammonia water flow rate, which will cause problems such as waste of ammonia water or excessive NOx emissions. Utility Model Content
[0004] To solve or partially solve the problems existing in the related technologies, this application provides an SNCR denitrification environmental protection system for stable operation, energy conservation and consumption reduction, which can reduce the ammonia water consumption and save the operation cost of the denitrification device.
[0005] This application provides an SNCR denitrification environmental protection system for stable operation, energy conservation and consumption reduction, including an ammonia water supply system 1, a dilution metering system 2, a dilution water supply system 3, a flow distribution system 4, an injection system 5, an electrical control system and a CEMS on-line monitoring system; the ammonia water supply system 1 and the dilution water supply system 3 are respectively connected to the dilution metering system 2, the dilution metering system 2 is connected to the flow distribution system 4, the flow distribution system 4 is connected to the injection system 5, the CEMS on-line monitoring system is installed at the flue gas outlet, and the electrical control system is electrically connected to the ammonia water supply system 1, the dilution metering system 2, the dilution water supply system 3, the flow distribution system 4, the injection system 5 and the CEMS on-line monitoring system respectively.
[0006] The injection system 5 includes a spray gun and a regulating valve, and the through-flow cross-sectional diameters of the valve core 8 and the valve seat 9 of the regulating valve are 6 mm.
[0007] Optionally, in some solutions, a reaction water recovery system 6 is provided at the flue gas outlet, and the reaction water recovery system 6 is connected to the dilution water supply system 3.
[0008] Optionally, in some solutions, the flow distribution system 4 is connected to a compressed air supply system 7.
[0009] The technical solutions provided in this application may include the following beneficial effects:
[0010] This application improves the adjustment accuracy of the ammonia water regulating valve of the device, strengthens and guarantees the stability of the operation control of the denitration device, reduces the ammonia water consumption, and saves the operation cost of the denitration device.
[0011] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] By describing the exemplary embodiments of the present application in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present application will become more obvious. Among them, in the exemplary embodiments of the present application, the same reference numerals generally represent the same components.
[0013] Figure 1 is a structural block diagram of the SNCR denitration environmental protection system for stable operation and energy conservation and consumption reduction shown in Embodiment 1 of the present application;
[0014] Figure 2 is a structural schematic diagram of the regulating valve shown in the embodiment of the present application;
[0015] Figure 3 is a structural block diagram of the SNCR denitration environmental protection system for stable operation and energy conservation and consumption reduction shown in Embodiment 2 of the present application
[0016] Figure 4 is a structural block diagram of the SNCR denitration environmental protection system for stable operation and energy conservation and consumption reduction shown in Embodiment 3 of the present application.
[0017] REFERENCE SIGNS:
[0018] 1 - Ammonia water supply system, 2 - Dilution metering system, 3 - Dilution water supply system, 4 - Flow distribution system, 5 - Injection system, 6 - Reaction water recovery system, 7 - Compressed air supply system, 8 - Valve core, 9 - Valve seat. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0019] The following will describe the embodiments of the present application in more detail with reference to the drawings. Although the embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.
[0020] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality of" is two or more, unless otherwise specifically defined.
[0021] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to this application.
[0022] Unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0023] In view of the above problems, the embodiment of this application provides an SNCR denitration environmental protection system with stable operation and energy conservation and consumption reduction, which can reduce the ammonia water consumption and save the operation cost of the denitration device.
[0024] The technical solutions of the embodiments of this application will be described in detail below with reference to the drawings.
[0025] Embodiment 1
[0026] See Figure 1-2, the SNCR denitration environmental protection system for stable operation and energy conservation and consumption reduction includes an ammonia water supply system 1, a dilution metering system 2, a dilution water supply system 3, a flow distribution system 4, an injection system 5, an electrical control system, and a CEMS on-line monitoring system; the ammonia water supply system 1 and the dilution water supply system 3 are respectively connected to the dilution metering system 2, the dilution metering system 2 is connected to the flow distribution system 4, the flow distribution system 4 is connected to the injection system 5, the CEMS on-line monitoring system is installed at the flue gas outlet, and the electrical control system is electrically connected to the ammonia water supply system 1, the dilution metering system 2, the dilution water supply system 3, the flow distribution system 4, the injection system 5, and the CEMS on-line monitoring system respectively. The injection system 5 includes a spray gun and a regulating valve, and the flow cross-sectional diameters of the valve core 8 and the valve seat 9 of the regulating valve are 6 mm.
[0027] When performing SNCR denitration, the ammonia water solution with a concentration of 20% is pumped out from the ammonia water supply system 1, mixed and diluted with the process water from the dilution water supply system 3 in the dilution metering system 2 to form a dilute ammonia water solution, which is transported to the flow distribution system 4. After being split by the flow distribution system 4, it is transported to the injection system 5. Under the pressure of the transfer pump, when passing through the spray gun, the ammonia water solution is atomized and pushed by compressed air, and then sprayed into the furnace in a mist form, where it reacts with the nitrogen oxides in the flue gas to generate nitrogen, removing the nitrogen oxides, thereby achieving the denitration purpose; the best temperature window is selected to spray the reducing agent, and the ammonia water spray gun atomization design is adopted to spray the ammonia water solution into the outlet area of the boiler furnace for reaction, ensuring sufficient penetration depth and coverage.
[0028] Using ammonia water with a concentration of 20% as the reducing agent compared with liquid ammonia, if it overflows, the diffusion range of the ammonia water liquid is smaller than that of liquid ammonia, and the concentration range is easier to control; lower power demand; using a liquid rather than a gaseous reactant can more effectively control the reactant injection mode and reactant distribution, ensure good mixing with the flue gas, and enable the chemical agent to be more fully utilized with a lower NH3 escape.
[0029] The CEMS on-line monitoring system monitors the N0x content at the flue gas outlet in real time, and controls the overall operation of the system through the electrical control system. When designing the SNCR denitration system, the characteristics of the boiler itself operation are taken into account, ensuring the lowest impact on the boiler thermal efficiency while achieving high-efficiency denitration and low ammonia escape, and both the system power consumption and energy consumption are relatively low.
[0030] The computational fluid dynamics simulation technology (CFD) and chemical kinetics simulation technology (CKM) are used to evaluate the denitrification capacity of the denitrification process on the unit, and to determine the injection scheme and injection position of the spray gun. The CFD simulation technology is used to predict the expected temperature values and flow patterns in the boiler and flue, and the CKM simulation technology is used to predict the denitrification capacity and product emissions of the set baseline under various different load conditions. This baseline is a function of the chemical release and reagent flow rate relationship. Then, the CFD simulation technology is used to evaluate the injection scheme that can meet the chemical release requirements determined by CKM to achieve the maximum degree of denitrification; the temperature-residence time data calculated according to the CFD model is used as the input parameter for the CKM calculation. Through the CKM simulation calculation under different working conditions, the expected denitrification reaction temperature control range is determined, the position and layout control plan of the nozzle are determined, and the test verification is carried out on the test device according to the simulation results, and the design is corrected. Through these procedures, the optimization of the injection system design is ensured. Controlling the ammonia-nitrogen ratio (NSR) is crucial for the denitrification system. A suitable NSR is the guarantee of high efficiency, low escape, and low operating cost. In the design, the optimization of the injection system and sensitive injection flow rate distribution control are used to ensure that the NSR operating value of the system is relatively low. During the operation and commissioning, the flow rate of each nozzle is also calibrated, and the design control strategy is optimized by combining the test data with practical experience to quickly respond to the fluctuations of the boiler operating parameters and NOX emissions.
[0031] Determination of the through-flow cross-section diameters of the valve core 8 and valve seat 9 of the regulating valve to be 6 mm:
[0032] During the operation of the SNCR denitrification environmental protection device, due to the relatively simple device, equipment, and process principle, with the goal of monitoring NOX up-to-standard emissions and the characteristics of short operation control response time, it can perform operation control in a timely and efficient manner to ensure the real-time up-to-standard emissions of NOX; the stability during the operation of the SNCR denitrification environmental protection device is mainly affected by factors such as ammonia water quality, compressed air, the mixing effect of ammonia water dilution water, and the supply of ammonia water reductant. Among them, the fluctuation of the supply of the reductant ammonia water is the core of the stable operation of the system, and it is also the main control point for energy conservation and consumption reduction during the operation of the SNCR denitrification environmental protection device.
[0033] After statistics, under the condition of 30% opening of the valve, the ammonia water flow rates under the operations of different operators are not much different, and it is difficult to perform coarse and fine adjustment of the opening of the ammonia water regulating valve and the ammonia water supply; during the operation adjustment, it is necessary to input a decimal point on the keyboard for adjustment, and it is difficult to adjust the opening of the regulating valve (<20%) and the ammonia water flow rate one by one. There is a phenomenon of ammonia water waste of "low emissions, high consumption". By adjusting the opening of the ammonia water regulating valve and measuring the ammonia water flow rate, as shown in Table 1.
[0034] Table 1 Statistical table of the opening of the regulating valve and the ammonia water flow rate
[0035]
[0036]
[0037] Through on-site verification, it is found that there is no linear relationship between the opening of the regulating valve and the ammonia water flow rate.
[0038] When the opening of the ammonia water regulating valve is less than 10%, there is an adjustment dead zone for the regulating valve. At this time, the regulating valve cannot perform real-time linear regulation. Combining with the working principle of the regulating valve, when the valve core and valve seat diameters are relatively large and the slope of the valve core is too large, the flow area corresponding to the valve opening is relatively large, resulting in too high a flow rate. Even very slight movements can cause large flow rate fluctuations. Therefore, while ensuring that the fluid meets the maximum process flow rate requirements, reducing the diameters of the valve core and valve seat and reducing the slope of the valve core become the key for the ammonia water regulating valve to be stably controlled to ensure NO X to meet the discharge standards while realizing fine operation control, so as to achieve the goals of stable operation and energy conservation and consumption reduction of the denitration device.
[0039] After changing the diameters of the valve core and valve seat of the regulating valve to 7 mm, the flexibility of the ammonia water spray gun and adjustment control, and the linear relationship between the opening of the regulating valve and the ammonia water flow rate have all changed compared with before the diameter change. However, the graph of the opening of the regulating valve (<20%) and the ammonia water flow rate is still non-linear. After further discussion and innovative attempts, it is decided to change the diameters of the valve core and valve seat of the regulating valve from 7 mm to 6 mm and conduct tests again. In the case where the diameter of the flow-through cross-section of the ammonia water regulating valve is only 7 mm, in an innovative way, multiple attempts are made to change the diameters of the valve core and valve seat of the regulating valve (reduce to 6 mm) twice and try them out. The relationship between the opening of the regulating valve and the ammonia water flow rate is changed from non-linear to linear. At the same time, the flow rate at each opening is significantly lower than before the transformation. As shown in Table 2.
[0040] Table 2 Statistical table of the opening of the regulating valve with different sizes and the ammonia water flow rate
[0041]
[0042]
[0043] The accuracy of the ammonia water regulating valve of the denitration device has been improved, the adjustment process is more stable, and the operation of the device is more stable.
[0044] Example 2
[0045] As Figure 3 shown, on the basis of Example 1, a reaction water recovery system 6 is provided at the flue gas outlet, and the reaction water recovery system 6 is connected to the dilution water supply system 3.
[0046] During operation, the water generated after the reaction of the device is collected into the reaction water recovery system 6. After being filtered by the reaction water recovery system 6, the water is transported to the dilution water supply system 3 for recycling, avoiding waste of water resources.
[0047] Example 3
[0048] As Figure 4 shown, on the basis of Example 2, the flow distribution system 4 is connected to a compressed air supply system 7.
[0049] During operation, the compressed air supply system 7 serves as the atomization power source for the reducing agent, initially atomizing the ammonia water in the flow distribution system 4, and then being atomized again through the spray gun, ensuring good mixing with the flue gas, and enabling the chemical agent to be utilized more fully with a lower NH3 escape.
[0050] Finally, it should also be noted that in this article, relationships such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms including, containing, or any other variant are intended to cover non-exclusive inclusion, so that a process, method, article, or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article, or device.
[0051] The unit described as a separation component may or may not be physically separated, and the component shown as a unit may or may not be a physical unit, that is, it may be located in one place, or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0052] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technologies in the market, or to enable other ordinary technicians in the technical field to understand the embodiments disclosed herein.
Claims
1. An SNCR denitration environmental protection system for stable operation, energy conservation and consumption reduction, characterized in that: The SNCR denitration environmental protection system for stable operation and energy conservation and consumption reduction includes an ammonia water supply system (1), a dilution metering system (2), a dilution water supply system (3), a flow distribution system (4), an injection system (5), an electrical control system and a CEMS on-line monitoring system; the ammonia water supply system (1) and the dilution water supply system (3) are respectively connected to the dilution metering system (2), the dilution metering system (2) is connected to the flow distribution system (4), the flow distribution system (4) is connected to the injection system (5), the CEMS on-line monitoring system is installed at the flue gas outlet, and the electrical control system is electrically connected to the ammonia water supply system (1), the dilution metering system (2), the dilution water supply system (3), the flow distribution system (4), the injection system (5), and the CEMS on-line monitoring system respectively; The injection system (5) includes a spray gun and a regulating valve, and the through-flow cross-sectional diameters of the valve core (8) and the valve seat (9) of the regulating valve are 6 mm.
2. The SNCR denitration environmental protection system for stable operation and energy conservation and consumption reduction according to claim 1, characterized in that: A reaction water recovery system (6) is arranged at the flue gas outlet, and the reaction water recovery system (6) is connected to the dilution water supply system (3).
3. The SNCR denitration environmental protection system for stable operation and energy conservation and consumption reduction according to claim 2, wherein: The flow distribution system (4) is connected with a compressed air supply system (7).