Ammonia desulfurization system and method for reducing ammonia escape

Abstract

The invention discloses an ammonia desulfurization system and method for reducing ammonia escape, and belongs to the technical field of flue gas ammonia desulfurization, the ammonia desulfurization system comprises a desulfurization tower, the inner part of the desulfurization tower is sequentially provided with a demisting section, an absorption section, an oxidation section, a concentration cooling section and a crystallization section from top to bottom; a flue gas inlet is formed in the side wall of the concentration cooling section of the desulfurization tower and is used for allowing flue gas to enter. According to the invention, through measures of real-time monitoring and adjustment, accurate liquid supply, waste reduction, absorption efficiency improvement and the like, optimized utilization of resources is realized, accurate use of ammonia water or an ammonia solution is ensured, and the desulfurization efficiency and the generation amount of ammonium sulfate are improved. And through means of parameter optimization, automatic adjustment, fault early warning and processing, environmental adaptability and the like, the overall stability of the system is remarkably improved, continuous and stable operation of the system under different working conditions is guaranteed, errors caused by manual operation are reduced, the automatic adjustment capacity and the environmental adaptability of the system are enhanced, and the working efficiency of the system is improved. Therefore, both environmental protection and economic benefits are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of flue gas ammonia desulfurization, and in particular relates to an ammonia desulfurization system and method for reducing ammonia escape. Background Art

[0002] Ammonia desulfurization is currently a more commonly used flue gas desulfurization method. It has the advantages of high desulfurization efficiency and wide application range. In addition, the ammonium sulfite generated in the desulfurization process reacts chemically with oxygen in the air in the oxidation section to generate ammonium sulfate, which is then concentrated and crystallized to produce solid ammonium sulfate byproducts. This byproduct can also be used to prepare fertilizers, which can achieve effective utilization of resources. Although the desulfurization tower design in the prior art has detailed division of different functional sections, it lacks the application of automatic control systems. This means that the operation process may require more manual intervention, increasing the complexity of the operation and the possibility of error. Manual adjustment of parameters may lead to prolonged reaction time, affecting desulfurization efficiency and ammonia slip control.

[0003] Based on this, the present invention designs an ammonia desulfurization system and method for reducing ammonia slip to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problem and to propose an ammonia desulfurization system and method for reducing ammonia slip.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: An ammonia desulfurization system for reducing ammonia escape comprises: a desulfurization tower, wherein the interior of the desulfurization tower is provided with a demisting section, an absorption section, an oxidation section, a concentration and cooling section, and a crystallization section in sequence from top to bottom; The side wall of the concentration and cooling section of the desulfurization tower is provided with a flue gas inlet for the entry of flue gas; the side wall of the concentration and cooling section of the desulfurization tower is provided with a liquid discharge port for discharging concentrated liquid; A spraying system, including multiple spraying layers, for spraying ammonia water or ammonia solution to the absorption section and the concentration and cooling section; The ammonia escape recovery device is located after the demisting section of the desulfurization tower and is used to capture and recover the escaped ammonia; The control system is used to monitor and adjust the ammonia concentration, pH value, temperature and other parameters in the desulfurization tower in real time.

[0006] As a further description of the above technical solution: The absorption section of the desulfurization tower adopts a double-layer filler structure to improve the gas-liquid contact efficiency.

[0007] As a further description of the above technical solution: The ammonia escape recovery device comprises at least one absorption tower filled with an absorbent for absorbing ammonia in the flue gas.

[0008] As a further description of the above technical solution: (1) SO2 and ammonia concentration monitor, used to monitor the SO2 concentration in flue gas and the ammonia concentration in the absorption liquid in real time; (2) Automatic regulating valve, used to adjust the supply of ammonia water according to monitoring data; (3) Data processing unit, used to analyze monitoring data and optimize the operating parameters of the sprinkler system.

[0009] And includes the following steps: Real-time data collection: collect data such as SO2 concentration, ammonia concentration, pH value, temperature, etc. through sensors; Data processing: process the collected data and calculate the deviation and adjustment amount; Control decision: Calculate the adjustment amount according to the algorithm formula and generate the control command; Execution command: Adjust the ammonia supply, temperature and other parameters through automatic control valves and other actuators.

[0010] An ammonia desulfurization method for reducing ammonia slip comprises the following steps: S1. Flue gas enters the concentration and cooling section of the desulfurization tower through the flue gas inlet and is cooled to below 60°C through the spray system; S2, the concentrated liquid is discharged through the drain port and enters the crystallization tank. The upper concentrated liquid in the crystallization tank overflows into the concentration circulation tank and is sent back to the spray system through the concentration pump; S3. When the solid content in the crystallization tank reaches a set threshold, the solid is discharged for recovery; S4, in the absorption section, ammonia water or ammonia solution is sprayed through the spray system to react with SO2 in the flue gas to form ammonium sulfate; S5, in the oxidation stage, oxidizing the ammonium sulfite to ammonium sulfate by an oxidant; S6, capturing and recovering the escaped ammonia after the demisting section through an ammonia escape recovery device; S7. The operating parameters in the desulfurization tower are monitored and adjusted in real time through the control system to optimize the desulfurization efficiency and reduce ammonia escape.

[0011] As a further description of the above technical solution: The concentration of the ammonia water or ammonia solution injected in step S4 is automatically adjusted by a control system to maintain the best desulfurization efficiency and the lowest ammonia slip.

[0012] As a further description of the above technical solution: The ammonia gas recovered in step S6 can be converted into ammonia water or ammonia solution and reused in the spraying system.

[0013] As a further description of the above technical solution: The operating parameters in step S7 include ammonia concentration, pH value, spray liquid temperature and flue gas flow rate.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention realizes the optimal utilization of resources, ensures the accurate use of ammonia water or ammonia solution, and improves the desulfurization efficiency and the amount of ammonium sulfate generated through measures such as real-time monitoring and adjustment, precise liquid supply, waste reduction and absorption efficiency improvement. The system also significantly improves the overall stability through parameter optimization, automatic adjustment, fault warning and processing, and environmental adaptability, ensures the continuous and stable operation of the system under different working conditions, reduces the errors of human operation, and enhances the system's automatic adjustment ability and environmental adaptability, thereby achieving a dual improvement in environmental protection and economic benefits; 2. The present invention optimizes the absorption section by using a double-layer filler design, greatly improving the desulfurization performance and effectively removing sulfur dioxide from the flue gas. In addition, the system is specially equipped with ammonia escape recovery equipment to efficiently capture and recover the escaped ammonia, greatly reducing ammonia emissions and thus significantly reducing the environmental burden; 3. The present invention achieves significant environmental protection and comprehensive improvement of economic efficiency. The system effectively reduces ammonia escape, reduces harmful gas emissions, and imposes less burden on the environment. At the same time, by reducing ammonia loss and fine-tuning operating parameters, it not only reduces operating costs, but also increases the output of valuable by-products such as ammonium sulfate, thereby significantly enhancing the economic benefits of the system.

[0015] 4. The flexibility of the system operation in the present invention is also improved. Thanks to the application of automatic regulating valves and advanced data processing units, the system can intelligently adapt to various working conditions, ensuring the convenience and adaptability of operation. In addition, the system realizes the recycling of resources, converting the recovered ammonia gas into ammonia water or ammonia solution and re-injecting it into the spraying system. This closed-loop process not only improves the efficiency of resource use, but also embodies the concept of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structural composition of an ammonia desulfurization system for reducing ammonia slip proposed by the present invention; Figure 2 A schematic diagram of the steps of a control system for an ammonia desulfurization system for reducing ammonia slip proposed by the present invention; Figure 3 The present invention provides a schematic diagram of the steps of an ammonia-based desulfurization method for reducing ammonia slip.

[0017] Description of reference numerals: 1. Desulfurization tower; 2. Demisting section; 3. Absorption section; 4. Oxidation section; 5. Concentration and cooling section; 6. Crystallization section; 7. Flue gas inlet; 8. Drain port; 9. Spray layer; 10. Ammonia escape recovery device; 11. Absorption tower. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0019] Please see attached Figure 1 -Attached Figure 3 The present invention provides a technical solution: an ammonia desulfurization system for reducing ammonia escape, comprising: a desulfurization tower, wherein the desulfurization tower is provided with a demisting section, an absorption section, an oxidation section, a concentration and cooling section, and a crystallization section in sequence from top to bottom; The side wall of the concentration and cooling section of the desulfurization tower is provided with a flue gas inlet for the entry of flue gas; the side wall of the concentration and cooling section of the desulfurization tower is provided with a liquid discharge port for discharging concentrated liquid; A spraying system, including multiple spraying layers, for spraying ammonia water or ammonia solution to the absorption section and the concentration and cooling section; The ammonia escape recovery device is located after the demisting section of the desulfurization tower and is used to capture and recover the escaped ammonia; The control system is used to monitor and adjust the ammonia concentration, pH value, temperature and other parameters in the desulfurization tower in real time.

[0020] The absorption section of the desulfurization tower adopts a double-layer filler structure to improve the gas-liquid contact efficiency.

[0021] The ammonia escape recovery device comprises at least one absorption tower filled with an absorbent for absorbing ammonia in the flue gas.

[0022] The control system includes: (1) SO2 and ammonia concentration monitor, used to monitor the SO2 concentration in flue gas and the ammonia concentration in the absorption liquid in real time; (2) Automatic regulating valve, used to adjust the supply of ammonia water according to monitoring data; (3) Data processing unit, used to analyze monitoring data and optimize the operating parameters of the sprinkler system.

[0023] And includes the following steps: Real-time data collection: collect data such as SO2 concentration, ammonia concentration, pH value, temperature, etc. through sensors; Data processing: process the collected data and calculate the deviation and adjustment amount; Control decision: Calculate the adjustment amount according to the algorithm formula and generate the control command; Execution command: adjust the ammonia supply, temperature and other parameters through automatic regulating valves and other actuators; The ammonia supply adjustment algorithm is as follows: Formula: ΔQNH3=K1*(Ctarget-Ccurrent) Meaning: ΔQNH3 is the adjustment amount of ammonia water supply, K1 is the adjustment coefficient, Ctarget is the target ammonia concentration, and Ccurrent is the current ammonia concentration. This formula is used to adjust the supply of ammonia water according to the deviation of ammonia concentration.

[0024] SO2 concentration feedback control algorithm: Formula: ΔQNH3=K2*(Ctarget_SO2-Ccurrent_SO2)*(Ccurrent_NH3 / Cmax_NH3) Meaning: ΔQNH3 is the adjustment amount of ammonia supply, K2 is the adjustment coefficient, Ctarget_SO2 is the target SO2 concentration, Ccurrent_SO2 is the current SO2 concentration, Ccurrent_NH3 is the current ammonia concentration, and Cmax_NH3 is the maximum allowable value of ammonia concentration. This formula takes into account the deviation of SO2 concentration and the current level of ammonia concentration to adjust the ammonia supply.

[0025] pH control algorithm: Formula: ΔQNH3=K3*(pHtarget-pHcurrent) Meaning: ΔQNH3 is the adjustment amount of ammonia supply, K3 is the adjustment coefficient, pHtarget is the target pH value, and pHcurrent is the current pH value. pH value is an important factor affecting desulfurization efficiency. This formula is used to adjust the ammonia supply according to the deviation of pH value.

[0026] Temperature control algorithm: Formula: ΔT=K4*(Ttarget-Tcurrent) Meaning: ΔT is the temperature adjustment amount, K4 is the adjustment coefficient, Ttarget is the target temperature, and Tcurrent is the current temperature. Temperature affects the volatility and desulfurization efficiency of ammonia. This formula is used to adjust the temperature of the spray system; The model is built using the PID (Proportional-Integral-Derivative) control algorithm: Proportional (P): Directly proportional to the current error, used to respond quickly to errors.

[0027] P=Kp×e(t) where Kp is the proportional gain and e(t) is the current error (the difference between the target value and the actual value).

[0028] Integral (I): Proportional to the integral of the error and is used to eliminate steady-state errors.

[0029] I=Ki×∫e(t)dt where Ki is the integral gain.

[0030] Derivative (D): Proportional to the rate of change of the error and used to predict the changing trend of the error.

[0031] D=Kd×de(t)dt where Kd is the differential gain.

[0032] PID controller output formula: Optimal_Parameters=P+I+D; An ammonia desulfurization method for reducing ammonia slip comprises the following steps: S1. Flue gas enters the concentration and cooling section of the desulfurization tower through the flue gas inlet and is cooled to below 60°C through the spray system; S2, the concentrated liquid is discharged through the drain port and enters the crystallization tank. The upper concentrated liquid in the crystallization tank overflows into the concentration circulation tank and is sent back to the spray system through the concentration pump; S3. When the solid content in the crystallization tank reaches a set threshold, the solid is discharged for recovery; S4, in the absorption section, ammonia water or ammonia solution is sprayed through the spray system to react with SO2 in the flue gas to form ammonium sulfate; S5, in the oxidation stage, oxidizing the ammonium sulfite to ammonium sulfate by an oxidant; S6, capturing and recovering the escaped ammonia after the demisting section through an ammonia escape recovery device; S7, monitor and adjust the operating parameters in the desulfurization tower in real time through the control system to optimize the desulfurization efficiency and reduce ammonia slip; The concentration of the ammonia water or ammonia solution sprayed in step S4 is automatically adjusted by the control system to maintain the best desulfurization efficiency and the lowest ammonia escape. The ammonia gas recovered in step S6 can be converted into ammonia water or ammonia solution and reused in the spraying system. The operating parameters in step S7 include ammonia concentration, pH value, spray liquid temperature and flue gas flow rate.

[0033] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An ammonia desulfurization system for reducing ammonia slip, characterized in that: include: A desulfurization tower, wherein the desulfurization tower is provided with a demisting section, an absorption section, an oxidation section, a concentration and cooling section, and a crystallization section in sequence from top to bottom; The side wall of the concentration and cooling section of the desulfurization tower is provided with a flue gas inlet for the entry of flue gas; the side wall of the concentration and cooling section of the desulfurization tower is provided with a liquid discharge port for discharging concentrated liquid; A spraying system, including multiple spraying layers, for spraying ammonia water or ammonia solution to the absorption section and the concentration and cooling section; The ammonia escape recovery device is located after the demisting section of the desulfurization tower and is used to capture and recover the escaped ammonia; The control system is used to monitor and adjust the ammonia concentration, pH value, temperature and other parameters in the desulfurization tower in real time.

2. The ammonia desulfurization system for reducing ammonia slip according to claim 1, characterized in that: The absorption section of the desulfurization tower adopts a double-layer filler structure to improve the gas-liquid contact efficiency.

3. The ammonia desulfurization system for reducing ammonia slip according to claim 1, characterized in that: The ammonia escape recovery device comprises at least one absorption tower filled with an absorbent for absorbing ammonia in the flue gas.

4. The ammonia desulfurization system for reducing ammonia slip according to claim 1, characterized in that: The control system comprises: (1) SO2 and ammonia concentration monitor, used to monitor the SO2 concentration in flue gas and the ammonia concentration in the absorption liquid in real time; (2) Automatic regulating valve, used to adjust the supply of ammonia water according to monitoring data; (3) Data processing unit, used to analyze monitoring data and optimize the operating parameters of the sprinkler system.

5. And include the following steps: Real-time data collection: collect data such as SO2 concentration, ammonia concentration, pH value, temperature, etc. through sensors; Data processing: process the collected data and calculate the deviation and adjustment amount; Control decision: Calculate the adjustment amount according to the algorithm formula and generate the control command; Execution command: Adjust the ammonia supply, temperature and other parameters through automatic control valves and other actuators.

6. An ammonia-based desulfurization method for reducing ammonia slip, according to an ammonia-based desulfurization system for reducing ammonia slip according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Flue gas enters the concentration and cooling section of the desulfurization tower through the flue gas inlet and is cooled to below 60°C through the spray system; S2, the concentrated liquid is discharged through the drain port and enters the crystallization tank. The upper concentrated liquid in the crystallization tank overflows into the concentration circulation tank and is sent back to the spray system through the concentration pump; S3. When the solid content in the crystallization tank reaches a set threshold, the solid is discharged for recovery; S4, in the absorption section, ammonia water or ammonia solution is sprayed through the spray system to react with SO2 in the flue gas to form ammonium sulfate; S5, in the oxidation stage, oxidizing the ammonium sulfite to ammonium sulfate by an oxidant; S6, capturing and recovering the escaped ammonia after the demisting section through an ammonia escape recovery device; S7. The operating parameters in the desulfurization tower are monitored and adjusted in real time through the control system to optimize the desulfurization efficiency and reduce ammonia escape.

7. The ammonia desulfurization method for reducing ammonia slip according to claim 5, characterized in that: The concentration of the ammonia water or ammonia solution injected in step S4 is automatically adjusted by a control system to maintain the best desulfurization efficiency and the lowest ammonia slip.

8. The ammonia desulfurization method for reducing ammonia slip according to claim 5, characterized in that: The ammonia gas recovered in step S6 can be converted into ammonia water or ammonia solution and reused in the spraying system.

9. The ammonia desulfurization method for reducing ammonia slip according to claim 5, characterized in that: The operating parameters in step S7 include ammonia concentration, pH value, spray liquid temperature and flue gas flow rate.

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