Oxidizing air multipurpose system for desulfurization system

Abstract

The utility model relates to the technical field of flue gas desulfurization, and specifically relates to a desulfurization system oxidation air multipurpose system. The primary circulation system and the secondary circulation system are connected by an inlet flue, and the original flue gas flows through the primary circulation system and the secondary circulation system in sequence to carry out the desulfurization process. The primary circulation system includes two primary oxidation air fans, each of which is connected to the absorption tower through the same outlet pipeline. The primary oxidation air fan is used to introduce oxidation air into the outlet pipeline. The outlet pipeline is connected with a cleaning air pipeline and a sealing air pipeline. The cleaning air pipeline is connected to the wet electric dust collector to introduce cleaning air into the wet electric dust collector. The sealing air pipeline is connected to the accident spraying pipeline of the absorption tower to introduce sealing air into the accident spraying pipeline. The system improves the resource utilization rate and energy efficiency of the oxidation air system and avoids the investment waste caused by the repeated construction of the auxiliary air system, thereby significantly reducing the system operation and maintenance costs.

Description

Technical Field

[0001] This utility model relates to the field of flue gas desulfurization technology, specifically to a multi-purpose oxidation air system for desulfurization systems. Background Technology

[0002] In current thermal power unit desulfurization systems, with the continuous improvement of environmental standards and the increasing requirements for desulfurization efficiency, flue gas desulfurization technology has been widely applied. Among them, the limestone-gypsum wet desulfurization process has become the mainstream desulfurization process route due to its mature technology, high efficiency, and stable operation. In this type of desulfurization system, the oxidation blower, as one of the core devices that provides oxidizing air to the slurry, directly affects the degree of complete oxidation of calcium sulfite and the stability of gypsum quality, and is an important guarantee for the stable operation of the system.

[0003] To ensure desulfurization efficiency, existing technologies generally employ a dual-circulation single-tower structure, where both the primary absorption tower and the AFT slurry tank are equipped with independent oxidation fans. This redundancy ensures the oxidation effect of the desulfurization reaction. Additionally, some systems incorporate emergency spray systems in the absorption tower to mitigate operational risks, using a dedicated air source for airtight isolation. However, these conventional solutions typically configure fan capacity based on design limits, failing to adequately account for fluctuations in actual operating conditions. Especially when unit load decreases or flue gas sulfur content drops, the system's oxidation air configuration often has a large margin, leading to lower energy efficiency. Furthermore, some auxiliary systems still rely on new equipment or external air sources, increasing operating and investment costs.

[0004] In view of the above, in order to overcome the above technical problems, this utility model designs a multi-purpose oxidation air system for desulfurization systems, which solves the above technical problems. Summary of the Invention

[0005] The technical objective of this invention is to provide a multi-purpose optimization system for oxidation air in desulfurization systems. By expanding the functional applications of oxidation air pipelines and introducing intelligent control methods, this system achieves integrated utilization and dynamic allocation of oxidation air resources, thereby improving overall system operating efficiency and reducing energy consumption and operating costs.

[0006] To achieve the above-mentioned technical objectives, this utility model provides the following technical solution:

[0007] This utility model provides a multi-purpose oxidation air system for desulfurization systems, comprising a primary circulation system and a secondary circulation system. Raw flue gas flows sequentially through the primary and secondary circulation systems via an inlet flue for desulfurization. The primary circulation system includes two primary oxidation fans, each connected to the absorption tower via the same outlet pipe. The primary oxidation fans supply oxidation air to the outlet pipe. A cleaning air duct and a sealing air duct are connected to the outlet pipe. The cleaning air duct connects to a wet electrostatic precipitator (ESP) and supplies cleaning air to it. The sealing air duct connects to the emergency spray pipe of the desulfurization absorption tower and supplies sealing air to it. The continuous supply of oxidation air by the primary oxidation fans ensures sufficient oxidation of the slurry. Simultaneously, the redundant airflow of the primary oxidation fans is used to export hot oxidation air for cleaning the ESP and sealing the emergency spray pipe.

[0008] The secondary circulation system includes an AFT slurry tank, AFT oxidation blowers, and an electrical control component. The AFT slurry tank receives the flue gas treated by the primary circulation system. The two AFT oxidation blowers supply oxidation air to the AFT slurry tank. The electrical control component is electrically connected to a sensor and controls the start and stop of the AFT oxidation blowers based on the sulfur dioxide content detected by the sensor in the inlet flue and the sulfur dioxide removal capacity of the primary oxidation blowers.

[0009] Specifically, if the residual SO2 concentration is high after the flue gas passes through the primary system, it needs to be further oxidized by the AFT system to ensure that the emission meets the standards. By comparing the SO2 detection data at the front end with the design removal capacity of the primary system, the system can automatically determine whether to start the AFT system, so as to achieve on-demand response and energy-saving operation.

[0010] Furthermore, both the cleaning air duct and the sealing air duct are connected to the outlet pipe; the cleaning air duct is connected first, followed by the sealing air duct, along the air flow direction within the outlet pipe. The connection sequence of the cleaning air duct and the sealing air duct is arranged based on the flow characteristics of the oxidation air within the pipe to improve the utilization efficiency of hot air energy and air pressure.

[0011] Preferably, the cleaning air is hot air at a temperature of not less than 75°C, and both the cleaning air and the sealing air originate from the redundant oxidation air flowing through the outlet duct. Since both the cleaning air and the sealing air come from the "redundant capacity" of the oxidation air system, it avoids the need for an independent air source system for each auxiliary function, eliminating the need for additional heat sources or fans, saving energy and equipment investment, and improving the overall economic efficiency of the system.

[0012] The cleaning air duct and the sealing air duct both include a duct body, a manual valve, an electric regulating valve, a temperature sensor and a flow sensor. The duct body is connected to the outlet duct, and the manual valve, the electric regulating valve, the temperature sensor and the flow sensor are installed in series along the air flow direction on the duct body.

[0013] The aforementioned electric valve, temperature sensor, and flow sensor work together to achieve closed-loop control of air volume and temperature, ensuring that each auxiliary function has a stable and appropriate airflow guarantee.

[0014] Preferably, the pipe body is a stainless steel pipe, and the outer wall of the pipe body is covered with thermal insulation cotton.

[0015] Preferably, a check valve is also installed on the pipeline body to prevent backflow of flue gas when the oxidation fan stops operating.

[0016] Preferably, both the primary oxidation fan and the AFT oxidation fan are 100% capacity single-stage high-speed centrifugal fans.

[0017] The electrical control components include a gas analysis sensor, a power sensor, a main controller, and an electrical control cabinet. The gas analysis sensor is installed in the inlet flue and is used to detect the sulfur dioxide content in the raw flue gas. The power sensor is installed on the main transformer outlet line and is used to detect the system's power data.

[0018] The main controller is used to receive sulfur dioxide content data from the gas analysis sensor and power data from the power sensor and send electrical signals; the electrical control cabinet is used to receive the electrical signals sent by the main controller and then control the start and stop of the AFT oxidation fan by executing switches.

[0019] When the sulfur dioxide content in the raw flue gas is not higher than the sulfur dioxide removal capacity of the primary oxidation blower, the electrical control cabinet controls the AFT oxidation blower to stop; when the sulfur dioxide content in the raw flue gas is higher than the sulfur dioxide removal capacity of the primary oxidation blower, the electrical control cabinet controls the AFT oxidation blower to start.

[0020] The beneficial effects of this utility model are as follows:

[0021] 1. This application achieves multi-purpose utilization of oxidation air by adding a cleaning air duct and a sealing air duct to the outlet pipe of the primary oxidation blower. These ducts direct redundant oxidation air resources for the cleaning air of the wet electrostatic precipitator and the sealing air for emergency spraying in the absorption tower, respectively. This is done without adding additional air source equipment. Based on the operating characteristic of desulfurization systems where oxidation air flow generally has a margin, this structure fully recovers and utilizes redundant air volume, not only improving the resource utilization rate and energy efficiency of the oxidation air system but also avoiding the investment waste caused by the repeated construction of auxiliary air systems, thereby significantly reducing system operation and maintenance costs.

[0022] 2. This application constructs an automatic control logic for adjusting air volume and temperature by installing electric regulating valves in the cleaning air duct and the sealing air duct, combined with gas temperature and flow parameters. It can dynamically adjust the delivery air volume and status according to actual operating needs, thereby ensuring the stability and adaptability of the wet electrostatic precipitator and the emergency spray function, and improving the safety and intelligence level of the system operation.

[0023] 3. This application uses an electronic control component to monitor the SO2 content in the inlet flue gas in real time and dynamically compares it with the removal capacity of the primary oxidation fan to automatically control the start and stop status of the AFT oxidation fan. This control strategy, combined with the DCS system, constructs an intelligent fan regulation mechanism based on pollutant load, realizing a linkage response between fan start / stop and changes in flue gas composition. This avoids ineffective operation of the oxidation fan under low-sulfur conditions and effectively reduces system energy consumption and equipment wear. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] The above and other aspects of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:

[0026] Figure 1 This is a schematic diagram of the pipeline of this utility model.

[0027] In the diagram: 1. Primary oxidation fan; 2. Outlet pipe; 3. Absorption tower; 4. Clean air duct; 5. Sealed air duct; 6. Wet electrostatic precipitator; 7. Emergency spray pipe; 8. Pipe body; 9. Manual valve; 10. Electric regulating valve; 11. Temperature sensor; 12. Flow sensor; 13. Check valve. Detailed Implementation

[0028] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0029] Example 1:

[0030] like Figure 1 As shown, in this embodiment, the primary circulation system of the desulfurization system is equipped with two 100% capacity single-stage high-speed centrifugal fans. The flow rate of the primary oxidation fan 1 is 12000 Nm3 / h, with one fan normally operating and the other on standby. The AFT slurry tank is equipped with two 100% capacity single-stage high-speed centrifugal fans, namely AFT oxidation fans, with a flow rate of 15000 Nm3 / h. One fan normally operates and the other on standby. Under the design conditions of the desulfurization system, the inlet concentration of sulfur dioxide in the raw flue gas is 3517. Under design conditions, the sulfur dioxide concentration at the outlet of the primary circulation is approximately 1367 mg / m3. Therefore, the oxidation blower of the absorption tower 3 corresponding to the primary circulation has the oxidation capacity to remove sulfur dioxide at a concentration of 2150 mg / m3. Taking advantage of the existing margin in the oxidation air of the desulfurization system, a cleaning air duct 4 is drawn from the outlet pipe 2 of the oxidation blower, consuming approximately 2000 Nm3 / h of oxidation air volume and hot air at a temperature not lower than 75℃, which is connected to the wet electrostatic precipitator 6 for use as the cleaning air of the wet electrostatic precipitator 6.

[0031] Furthermore, in this embodiment, another sealing air duct 5 is drawn from the outlet pipe 2 of the primary oxidation blower 1, consuming approximately 700 Nm3 / h of oxidation air volume, and connected to the emergency spray pipe 7 of the desulfurization absorption tower 3 as the sealing air for emergency spraying.

[0032] Both the cleaning air duct 4 and the sealing air duct 5 include a duct body 8, a manual valve 9, a check valve 13, an electric regulating valve 10, a temperature sensor 11, and a flow sensor 12. The manual valve 9, electric regulating valve 10, temperature sensor 11, and flow sensor 12 are installed in series along the airflow direction on the duct body 8. In this embodiment, a check valve 13 is also installed on the duct body 8 to prevent backflow of flue gas to the fan when the oxidation fan is stopped. The duct body 8 is made of stainless steel, and its outer wall is covered with insulation cotton to prevent heat loss and provide noise reduction.

[0033] In this embodiment, the flow sensor 12 and the electric regulating valve 10 in the primary oxidation fan 1 to the wet electrostatic precipitator cleaning air duct 4 form an automatic control logic. The control quantity of the flow sensor 12 is 2000 Nm3 / h, and the electric regulating valve 10 performs real-time automatic control operation to increase or decrease the flow rate according to the flow measurement point.

[0034] The flow sensor 12 in the AFT oxidation blower to the emergency spray sealing air duct 5 forms an automatic control logic with the electric regulating valve 10. The control quantity of the flow sensor 12 is 700 Nm3 / h. The electric regulating valve 10 performs real-time automatic control operation to increase or decrease the flow based on the flow sensor 12.

[0035] Example 2:

[0036] Based on the above embodiment 1, this embodiment can also control the start or stop of the AFT oxidation fan according to the current unit load value. Specifically, it includes determining whether the current unit load value is in a low load period. In this embodiment, the preset load is lower than 550MW. If so, it determines whether the AFT oxidation fan is in operation. If so, it sends a stop control signal to the AFT oxidation fan. If not, it does not send a control signal.

[0037] The start or stop of the AFT oxidation blower is controlled by whether the sulfur dioxide content in the raw flue gas at the current desulfurization system inlet is lower than 2000 mg / m3. Specifically, it involves determining whether the sulfur dioxide content in the raw flue gas at the current desulfurization system inlet is lower than 2000 mg / m3. If so, it determines whether the AFT oxidation blower is in operation. If so, a stop control signal is sent to the AFT oxidation blower. If not, no control signal is sent.

[0038] The control system in this embodiment implements its core control functions through a DCS (Distributed Control System). Its built-in load-fan linkage control module acts as the main controller, receiving relevant signals and outputting control commands. It also includes a power sensor for monitoring the unit load, installed on the main transformer's output line; the signal is synchronously transmitted to the DCS as the control basis. The realization from sensing to execution relies on the coordinated action of the following core components: the power sensor senses the unit load and transmits the electrical signal to the DCS; the control module within the DCS determines the load signal, and when it confirms that the load is below 550MW, it sends a control command to the oxidation fan's electrical control cabinet; the contactor within the electrical control cabinet acts as the execution switch, disconnecting the main circuit (during operation) or remaining disconnected (during shutdown) upon receiving the command, ultimately achieving shutdown control or status maintenance of the oxidation fan.

[0039] The system determines whether the sulfur dioxide content in the flue gas at the desulfurization system inlet is below 2000 mg / m³. If so, it acquires the current operating status of the AFT oxidation blower, including both running and shut-down states. Based on the current sulfur dioxide content in the flue gas at the desulfurization system inlet, the system controls the start or stop of the oxidation blower. The core control functions are implemented through the DCS, whose built-in load-blower linkage control module acts as the main controller, receiving relevant signals and outputting control commands. Sensors used to monitor the unit load are installed on the main transformer outlet lines; their signals are synchronously transmitted to the DCS as the basis for control. The power sensor senses the unit load and transmits the electrical signal to the DCS. The control module in the DCS judges the load signal. When the SO2 content of the raw flue gas at the desulfurization system inlet is lower than 2000mg / m³, it will trigger the oxidation fan shutdown command (if it is currently running). If it is already in a shutdown state, it will remain shut down. When the SO2 content of the raw flue gas at the desulfurization system inlet is higher than or equal to 2000mg / m³, it will trigger the oxidation fan start command (if it is currently shut down). If it is already in a running state, it will remain running.

[0040] In this embodiment, the core control logic is still handled by the DCS. The newly added SO2 content-fan linkage control module works in conjunction with the existing load-fan linkage control module, jointly receiving relevant signals and outputting corresponding control commands. The sensor used to monitor the SO2 content of the raw flue gas at the desulfurization system inlet is a gas analysis sensor, mainly installed on the inlet flue of the desulfurization system. It can directly collect the SO2 content information in the raw flue gas and transmit the signal to the DCS in real time, serving as an important basis for the control of the oxidation fan. The process from sensing to execution requires the coordinated cooperation of all core components: the gas analysis sensor senses the SO2 content in the raw flue gas and transmits the electrical signal to the DCS; the SO2 content-fan linkage control module in the DCS determines the SO2 content signal and sends corresponding control commands to the electrical control cabinet of the oxidation fan based on the comparison result with 2000mg / m³; the contactor (or solid-state relay) in the electrical control cabinet acts as an execution switch, and after receiving the command, it connects the main circuit (when in shutdown state), maintains the connected state (when in operation state), disconnects the main circuit (when in operation state), or maintains the disconnected state (when in shutdown state), ultimately realizing the start-up, operation maintenance, shutdown, or shutdown maintenance of the oxidation fan.

[0041] The description herein is provided to enable those skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of the disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be given the broadest scope consistent with the principles and novel features disclosed herein.

[0042] Although one or more exemplary embodiments of this disclosure have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the appended claims.

[0043] The above description is merely illustrative of this disclosure, and modifications may be made to the present invention in light of the above detailed description. The terminology used in the appended claims should not be construed as limiting the present invention to the specific embodiments disclosed in the specification. Rather, the scope of the present invention will be fully defined by the appended claims, which will be interpreted according to established principles of claim interpretation.

Claims

1. A multi-purpose desulfurization system with oxidation air, comprising a primary circulation system and a secondary circulation system, wherein the raw flue gas flows sequentially through the primary and secondary circulation systems via the inlet flue for desulfurization, characterized in that, The primary circulation system includes two primary oxidation blowers (1), each of which is connected to the absorption tower (3) through the same outlet pipe (2). The primary oxidation blower (1) is used to introduce oxidation air into the outlet pipe (2). The outlet pipe (2) is connected to a cleaning air pipe (4) and a sealing air pipe (5). The cleaning air pipe (4) is connected to a wet electrostatic precipitator (6) and is used to introduce cleaning air into the wet electrostatic precipitator (6). The sealing air pipe (5) is connected to the emergency spray pipe (7) of the absorption tower (3) and is used to introduce sealing air into the emergency spray pipe (7). The secondary circulation system includes an AFT slurry tank, AFT oxidation blowers, and an electrical control component. The AFT slurry tank is used to receive flue gas treated by the primary circulation system. The two AFT oxidation blowers are used to supply oxidation air to the AFT slurry tank. The electrical control component is electrically connected to sensors installed at the inlet flue and the system drive unit.

2. The multi-purpose desulfurization system oxidation air system according to claim 1, characterized in that: The cleaning air duct (4) and the sealing air duct (5) are both connected to the outlet pipe (2); the airflow in the outlet pipe (2) first flows through the cleaning air duct (4) and then through the sealing air duct (5).

3. The multi-purpose desulfurization system oxidation air system according to claim 1, characterized in that: The cleaning air is hot air at a temperature of not less than 75°C, and both the cleaning air and the sealing air come from the redundant oxidation air flowing through the outlet pipe (2).

4. The multi-purpose desulfurization system oxidation air system according to claim 2, characterized in that: The cleaning air duct (4) and the sealing air duct (5) both include a duct body (8), a manual valve (9), an electric regulating valve (10), a temperature sensor (11) and a flow sensor (12). The duct body (8) is connected to the outlet duct (2). The manual valve (9), the electric regulating valve (10), the temperature sensor (11) and the flow sensor (12) are installed in series along the air flow direction on the duct body (8).

5. The multi-purpose desulfurization system oxidation air system according to claim 4, characterized in that: The pipe body (8) is a stainless steel pipe.

6. The multi-purpose desulfurization system oxidation air system according to claim 4, characterized in that: The outer wall of the pipe body (8) is covered with thermal insulation cotton.

7. The multi-purpose desulfurization system oxidation air system according to claim 4, characterized in that: A check valve (13) is installed on the pipeline body (8) to prevent backflow of flue gas when the oxidation fan stops.

8. The desulfurization system oxidation air multipurpose system according to any one of claims 1-7, characterized in that: Both the primary oxidation blower (1) and the AFT oxidation blower are 100% capacity single-stage high-speed centrifugal blowers.

9. The multi-purpose desulfurization system oxidation air system according to claim 1, characterized in that: The electrical control assembly includes a sensor, a main controller, and an electrical control cabinet. The sensor is used to detect the sulfur dioxide content in the inlet flue and the power of the system drive. The main controller is electrically connected to the sensor. The electrical control cabinet is electrically connected to the main controller and is also electrically connected to the AFT oxidation fan via an actuation switch.

10. The multi-purpose desulfurization system oxidation air system according to claim 9, characterized in that: The sensors include a gas analysis sensor and a power sensor. The gas analysis sensor is installed inside the inlet flue and is used to detect the sulfur dioxide content in the raw flue gas. The power sensor is installed on the main transformer outlet line and is used to detect the system's power data.

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