Gas heater flue gas bypass system suitable for gas boiler

Abstract

The utility model discloses a gas heater flue gas bypass system suitable for a gas boiler, which comprises a boiler tail flue system, the boiler tail flue system comprises an outlet flue, the outlet flue is communicated with a desulfurizing tower through a main pipeline, the main pipeline is provided with a gas heater, and the outlet flue is additionally connected with a bypass conveying pipeline. One end of the bypass conveying pipeline is connected to the outlet flue through a flue gas bypass interface, the other end of the bypass conveying pipeline is communicated to the desulfurization tower, a monitoring and adjusting system is mounted on the bypass conveying pipeline, a monitoring and adjusting system is also mounted on the main pipeline and in front of the gas heater correspondingly, and a temperature detection point is mounted at a flue gas inlet of the desulfurization tower. The flue gas temperature and flow at the inlet of the desulfurization tower can be regulated and controlled, a stable flue gas source is provided for the desulfurization process, and normal flue gas desulfurization can still be ensured even if the gas heater is abnormal and the discharged flue gas cannot meet the desulfurization condition. The device disclosed by the utility model is crucial for ensuring the efficiency of the desulfurization process and the safety of the system.

Description

Technical Field

[0001] This utility model relates to the field of boiler flue gas utilization technology, and in particular to a flue gas bypass system for a gas heater suitable for gas boilers. Background Technology

[0002] Under the same heat load, the exhaust volume of a gas-fired boiler is about 30% larger than that of a pulverized coal boiler. However, due to the limited volume of the boiler's downward flue, the heat exchange surface cannot be significantly increased. Therefore, when the flue gas exits from the lower air preheater, its temperature is significantly higher than that of a pulverized coal boiler. Current solutions primarily involve installing a gas heater after the gas boiler's outlet flue. This increases the fuel temperature and thus improves boiler thermal efficiency through heat transfer between the flue gas and the fuel gas. From a broader perspective, gas heaters are used to reduce boiler exhaust temperature, which is an effective way to improve boiler efficiency. However, this also significantly impacts the inlet flue gas temperature of the subsequent desulfurization tower. In dry desulfurization systems, the inlet flue gas temperature of the desulfurization tower must be maintained at around 120℃~150℃. Stable flue gas is crucial for improving desulfurization efficiency and achieving energy conservation and emission reduction. When the boiler load fluctuates (especially at low loads), even with appropriate system optimization, the structural characteristics of the coal feeder itself make it impossible to strictly guarantee a stable flue gas temperature and flow rate at the desulfurization tower. Utility Model Content

[0003] To solve the above-mentioned technical problems, this utility model designs a flue gas bypass system for a gas heater suitable for gas boilers.

[0004] The present invention adopts the following technical solution:

[0005] A flue gas bypass system for a gas heater in a gas boiler includes a boiler tail flue system. The boiler tail flue system includes an outlet flue, which is connected to a desulfurization tower via a main pipeline. A gas heater is installed on the main pipeline. A bypass pipeline is connected to the outlet flue, with one end connected to the outlet flue via a flue gas bypass interface and the other end connected to the desulfurization tower. A monitoring and control system is installed on the bypass pipeline, and a corresponding monitoring and control system is installed on the main pipeline before the gas heater. A temperature detection point is installed at the flue gas inlet of the desulfurization tower. This invention provides a bypass pipeline that directly connects the high-temperature flue gas from the outlet flue to the desulfurization tower via the flue gas bypass interface. Simultaneously, monitoring and control systems are dynamically interlocked with the temperature detection point at the flue gas inlet of the desulfurization tower on both the bypass pipeline and the main pipeline for monitoring and controlling the opening and closing of the bypass system.

[0006] Preferably, the monitoring and control system consists of an electric regulating valve, a temperature detection point, and a pressure detection point.

[0007] Preferably, the connection interface of the bypass delivery pipeline is sealed with a sealing material.

[0008] Preferably, the flue gas bypass interface is connected to the main pipeline located between the outlet flue and the monitoring and regulation system.

[0009] Preferably, the bypass delivery pipeline is divided into horizontal and vertical sections to minimize flue gas resistance.

[0010] Preferably, the system also includes a controller, which interlocks the temperature detection point at the flue gas inlet of the desulfurization tower with the two monitoring and regulation systems on the bypass pipeline and the main pipeline.

[0011] The beneficial effects of this utility model are: (1) Providing a stable source of flue gas for desulfurization: In the boiler gas heater system, the flue gas flows completely through the gas heater before being transferred to the desulfurization tower. When the boiler is running at low load, the flue gas after passing through the gas heater is heated and the temperature is even lower, which cannot meet the temperature requirements of the desulfurization tower at all; if the boiler load fluctuates greatly, the operating condition of the gas heater will also be affected, resulting in abnormal fluctuations in the heat exchange between the coal heater and the flue gas, which in turn leads to the inlet flue gas temperature of the desulfurization tower failing to meet the desulfurization requirements and affecting the desulfurization efficiency. Setting up a gas heater flue gas bypass can supply flue gas to the desulfurization tower through the bypass system when the boiler is running at low load or the load fluctuates greatly, providing a stable source of flue gas for the desulfurization system; (2) Improving system stability: The boiler tail desulfurization and denitrification system is an extremely important link. If an abnormal situation occurs, it will lead to the boiler outlet flue gas environmental monitoring data being unqualified, directly affecting the boiler production and operation. Setting up a gas heater flue gas bypass can prevent some abnormal situations in the system from being expanded or spread, and improve the stability of the system. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model;

[0013] In the diagram: 1. Boiler outlet flue, 2. Flue gas bypass interface, 3. Monitoring and regulation system, 4. Bypass transmission pipeline, 5. Gas heater, 6. Desulfurization tower. Detailed Implementation

[0014] The technical solution of this utility model will be further described in detail below through specific embodiments and with reference to the accompanying drawings:

[0015] Example: Figure 1As shown, a gas heater flue gas bypass system suitable for gas boilers includes a boiler tail flue system, which includes an outlet flue 1 connected to a desulfurization tower 6 via a main pipeline. A gas heater 5 is installed on the main pipeline. A bypass conveying pipeline 4 is connected to the outlet flue 1. One end of the bypass conveying pipeline is connected to the outlet flue 1 via a flue gas bypass interface 2, and the other end is connected to the desulfurization tower. A monitoring and regulation system 3 is installed on the bypass conveying pipeline. A corresponding monitoring and regulation system is also installed on the main pipeline before the gas heater. A temperature detection point is installed at the flue gas inlet of the desulfurization tower.

[0016] The monitoring and control system consists of an electric regulating valve, temperature detection points, pressure detection points, and flow detection points. The connection points of the bypass pipeline are sealed with sealing material. The flue gas bypass interface connects to the main pipeline located between the outlet flue and the monitoring and control system. The bypass pipeline is divided into horizontal and vertical sections. The system also includes a controller; the temperature detection point at the flue gas inlet of the desulfurization tower is interlocked with the two monitoring and control systems on the bypass pipeline and the main pipeline via the controller.

[0017] The flue gas from the tail end of the boiler flows through the main pipeline from the outlet flue to the gas heater. The heat of the flue gas is absorbed by the gas heater and reduced to a temperature range that meets the requirements of the desulfurization tower. The flue gas then continues forward, passing through the connecting main pipeline to the desulfurization tower inlet. The flue gas, now at a certain temperature, enters the desulfurization tower for desulfurization treatment. A flue gas bypass interface is opened before the monitoring and regulation system of the gas heater and the main pipeline, connecting to a bypass delivery pipeline. A portion of the flue gas can bypass the gas heater and reach the desulfurization tower directly via the monitoring and regulation system and the bypass delivery pipeline. This portion of the flue gas is directly taken from the boiler outlet flue and is not affected by the gas heater. When the temperature measured at the flue gas temperature measuring point at the desulfurization tower inlet is below 150℃, the monitoring and regulation system on the bypass delivery pipeline automatically starts, automatically adjusting the flue gas volume according to the flue gas conditions at the desulfurization tower inlet. As the boiler load increases and the outlet flue gas temperature also increases, the monitoring and regulation system automatically takes corresponding actions. When the flue gas temperature meets the desulfurization tower inlet temperature, the gas heater flue gas bypass system stops working.

[0018] For gas boilers, installing gas heaters to fully recover heat from flue gas, thereby improving boiler efficiency and saving fuel, is a good measure to optimize operating costs and ensure efficient energy utilization. Adding a bypass installation can further improve its operational level. Gas heater bypass installation is a process involving safety and technical details. Valves, pipes, expansion joints, etc., usually need to be installed according to the specific equipment model, installation environment, and safety regulations. Specific installation steps may vary depending on the equipment. Based on the equipment's operating status and actual site conditions, the installation location of the gas heater bypass is determined. Generally, the bypass point is selected upstream of the gas heater inlet valve, and the bypass is led to the desulfurization tower inlet pipe via a connecting pipe following the flue gas flow direction. Care should be taken to maintain a safe distance between the equipment and walls, ceilings, and other objects. The bypass pipe connection should be tight and leak-free, using suitable sealing materials. Necessary valves and instrument monitoring equipment should be installed on the bypass pipe to control the opening and closing of the bypass system.

[0019] The working principle of this utility model is as follows: By opening a bypass system before the monitoring and regulation system of the gas heater and the main pipeline, a portion of the flue gas can bypass the gas heater and directly reach the desulfurization tower through the regulating valve and connecting pipeline, ensuring the flue gas temperature required by the desulfurization tower. The temperature of this portion of flue gas is not affected by the gas heater and the usage can be automatically adjusted, thus solving the problem that the inlet flue gas temperature and flow rate requirements of the desulfurization tower can still be met when the gas heater is abnormal.

[0020] Compared to traditional methods where the tail gas flows entirely through the outlet flue to the gas heater before entering the desulfurization tower for desulfurization, this invention allows for the regulation of the inlet flue gas temperature and flow rate, providing a stable flue gas source for the desulfurization process. Even if the gas heater malfunctions or the discharged flue gas cannot meet the desulfurization requirements, the desulfurization process can still proceed normally. This system has a simple structure and low operating costs, making it crucial for ensuring the efficiency of the desulfurization process and the safety of the system.

[0021] The embodiments described above are merely preferred solutions of this utility model and are not intended to limit this utility model in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A gas heater flue gas bypass system for a coal gas boiler, comprising a boiler tail flue system including an outlet flue, the outlet flue being connected to a desulfurization tower through a main pipeline, a gas heater being installed on the main pipeline, characterized in that, The outlet flue is additionally connected with a bypass conveying pipeline, one end of the bypass conveying pipeline is connected to the outlet flue through a flue gas bypass interface, the other end is communicated to the desulfurization tower, a monitoring and adjusting system is installed on the bypass conveying pipeline, a monitoring and adjusting system is also installed on the main pipeline before the coal gas heater, and a temperature detection point is installed at the flue gas inlet of the desulfurization tower.

2. A gas heater flue gas bypass system for a gas-fired boiler as defined in claim 1, characterized in that The monitoring and adjusting system is composed of an electric regulating valve, a temperature detection point, a pressure detection point and a flow detection point.

3. A gas heater flue gas bypass system for a gas-fired boiler as set forth in claim 1, wherein, The connecting interface of the bypass conveying pipeline is sealed by sealing material.

4. A gas heater flue gas bypass system for a gas-fired boiler as set forth in claim 1, wherein, The flue gas bypass interface is connected to the main pipeline between the outlet flue and the monitoring and adjusting system.

5. A gas heater flue gas bypass system for a gas-fired boiler as set forth in claim 1, wherein, The bypass conveying pipeline is divided into a horizontal section and a vertical section.

6. A gas heater flue gas bypass system for a gas-fired boiler as set forth in claim 1, wherein, A controller is further included, the temperature detection point at the flue gas inlet of the desulfurization tower is interlocked controlled by the two monitoring and adjusting systems on the bypass conveying pipeline and the main pipeline through the controller.

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