A PLC automatic control system for waste heat of a gas generator

Abstract

The utility model relates to a kind of gas generator waste heat PLC automatic control system, including temperature sensor, first pressure sensor and first flow sensor, valve includes proportional regulating valve, pump machine includes first water pump and second water pump, first water pump and second water pump are connected with boiler respectively, and the water outlet of first water pump and second water pump and the water inlet of boiler are provided with second flow sensor and second pressure sensor;Temperature sensor, first pressure sensor, first flow sensor, second flow sensor and second pressure sensor are electrically connected with PLC controller;First water pump and second water pump are electrically connected with PLC controller respectively;Proportional regulating valve is electrically connected with PLC controller.The utility model detects the pressure, temperature and flow of boiler and flue, adjusts water pump and valve in combination with PLC controller, to provide hardware basis for improving waste heat utilization rate.

Description

Technical Field

[0001] This utility model relates to the field of intelligent boiler control technology, specifically to a PLC automatic control system for waste heat from a gas generator. Background Technology

[0002] Gas generators fully utilize various natural gas or other combustible gas fuels to convert thermal energy into kinetic energy. They offer advantages such as turning waste into resources, safe and convenient operation, high cost-effectiveness, low emissions, and suitability for combined heat and power (CHP) generation, resulting in a wide market application. However, the waste heat utilization of existing generator exhaust is not thorough enough. The main reasons for this problem are as follows:

[0003] 1. The flue valves, pumps and other equipment are mostly manually or simply linked for control, which makes it difficult to adjust flexibly according to the working conditions, resulting in poor waste heat utilization.

[0004] 2. Weak monitoring function: Although there is a liquid level detection mechanism in the boiler, it is not integrated with the high-efficiency control unit. It lacks comprehensive and real-time monitoring of temperature, pressure, flow rate and related parameters of the water supply system in the flue, making it difficult to detect and deal with abnormalities in a timely manner, which poses a safety risk.

[0005] 3. Poor coordination among components: There is a lack of intelligent linkage between equipment such as boilers, pumps, valves, and liquid level detection mechanisms, making it impossible to form a closed-loop control, resulting in low system stability and efficiency.

[0006] To solve the above problems, it is urgent to develop a generator boiler control system that can utilize waste heat. Utility Model Content

[0007] To address the problem of insufficient waste heat utilization from existing generator exhaust gases, this invention proposes a PLC automatic control system for waste heat from gas generators. By detecting the pressure, temperature, and flow rate of the boiler and flue, and combining this with the PLC controller to adjust the water pumps and valves, a hardware foundation is provided for improving waste heat utilization.

[0008] To achieve the above objectives, this utility model proposes a PLC automatic control system for waste heat from a gas generator, including a boiler. The boiler includes an inlet, an outlet, a furnace, and a flue. A pump is installed at the boiler inlet, and a liquid level detection mechanism is installed inside the boiler. A valve is installed on the flue. The system also includes a PLC controller. A temperature sensor, a first pressure sensor, and a first flow sensor are installed at the inlet of the flue. The valve includes a proportional regulating valve. The pump includes a first water pump and a second water pump. The first water pump and the second water pump are respectively connected to the boiler. A second flow sensor and a second pressure sensor are installed between the outlet of the first water pump and the outlet of the second water pump and the inlet of the boiler.

[0009] The temperature sensor, the first pressure sensor, the first flow sensor, the second flow sensor, and the second pressure sensor are all electrically connected to the PLC controller.

[0010] The first and second water pumps are electrically connected to the PLC controller, respectively.

[0011] The proportional control valve is electrically connected to the PLC controller.

[0012] Furthermore, a water supply pipeline is provided between the first water pump and the second water pump and the boiler. The water supply pipeline includes pipeline A and pipeline B. Pipeline A is an L-shaped pipeline with the vertical section pointing upwards, and pipeline B is an L-shaped pipeline with the vertical section pointing downwards. The first water pump and the second water pump are sequentially arranged on pipeline A. The vertical section of pipeline B is connected to the horizontal section of pipeline A and separates the first water pump and the second water pump.

[0013] The vertical section of pipe A is connected to the horizontal section of pipe B, and the other end of the horizontal section of pipe B is connected to the boiler.

[0014] The water supply pipeline adopts an L-shaped design with pipes A and B, and pipe B separates the first water pump and the second water pump. This structure makes the dual-pump water supply more reasonable. The second water pump can supply water independently, while the first water pump assists the second water pump in supplying water, so that the water supply matches the boiler heat exchange efficiency and ensures stable operation.

[0015] Furthermore, the first water pump is equipped with a frequency converter, which is communicatively connected to the PLC controller, and the first water pump is connected to the power supply through the frequency converter;

[0016] The second water pump is equipped with a circuit breaker and a relay. The second water pump is connected to the power supply through the normally open contact of the circuit breaker. The coil of the circuit breaker is connected to the normally open contact of the relay. The coil of the relay is connected to the output terminal of the PLC controller.

[0017] The second water pump uses a stable power frequency for water supply, while the first water pump uses a variable frequency drive to achieve matching between boiler water supply and power.

[0018] Furthermore, the liquid level detection mechanism includes a water level electrode sensor, the output terminal of which is connected to the input terminal of the PLC controller;

[0019] The water level electrode sensor is threadedly connected to the boiler.

[0020] Furthermore, the temperature sensor, the first pressure sensor, and the first flow sensor are connected to the flue flange, and the second flow sensor and the second pressure sensor are connected to the flange on the transverse section of the pipe B.

[0021] A temperature sensor detects the flue gas temperature, a first pressure sensor detects the steam pressure, and a first flow sensor detects the steam flow. Based on these parameters, the PLC controller can control the opening of the proportional regulating valve through PID control.

[0022] The second flow sensor detects the water supply flow rate, the second pressure sensor detects the water supply pressure, and the water level electrode sensor detects the water level inside the boiler. Based on these parameters, the PLC controller can adjust the power of the first water pump to regulate the water supply.

[0023] Furthermore, the PLC controller is communicatively connected to an HMI module.

[0024] The beneficial effects of this utility model through the above technical solution are as follows:

[0025] This invention solves the problem of insufficient utilization of waste heat from generator exhaust. A temperature sensor detects the flue gas temperature, a first pressure sensor detects the steam pressure, and a first flow sensor detects the steam flow rate. Based on these parameters, a PLC controller provides the hardware foundation for controlling the opening of a proportional regulating valve via PID control, thereby achieving full utilization of waste heat. This improves upon relatively coarse control by providing finer control. A second flow sensor detects the water supply flow rate, a second pressure sensor detects the water supply pressure, and a water level electrode sensor detects the water level inside the boiler. Based on these parameters, the PLC controller can adjust the power of the first water pump to regulate the water supply. This provides the hardware foundation for stable boiler operation. Attached Figure Description

[0026] Figure 1 This is one of the circuit diagrams for a PLC automatic control system for waste heat from a gas generator according to this utility model;

[0027] Figure 2 This is the second circuit diagram of a PLC automatic control system for waste heat from a gas generator according to this utility model.

[0028] Figure 3 This is a schematic diagram of a PLC automatic control system for waste heat from a gas generator according to this utility model.

[0029] Reference numerals: 1 for boiler, 2 for flue, 5 for temperature sensor, 6 for first pressure sensor, 7 for first flow sensor, 8 for proportional control valve, 9 for first water pump, 10 for second water pump, 11 for second flow sensor, 12 for second pressure sensor, 13 for PLC controller, 14 for water supply pipeline, 15 for frequency converter, 16 for circuit breaker, 17 for relay, 18 for water level electrode sensor, 19 for HMI module. Detailed Implementation

[0030] Example 1

[0031] like Figures 1-3 As shown, a PLC automatic control system for waste heat from a gas generator includes a boiler 1, which includes an inlet, an outlet, a furnace, and a flue 2. A pump is installed at the inlet of the boiler 1, a liquid level detection mechanism is installed inside the boiler 1, and a valve is installed on the flue 2. The system also includes a PLC controller 13. A temperature sensor 5, a first pressure sensor 6, and a first flow sensor 7 are installed at the inlet of the flue 2. The valve includes a proportional regulating valve 8. The pump includes a first water pump 9 and a second water pump 10. The first water pump 9 and the second water pump 10 are respectively connected to the boiler 1. A second flow sensor 11 and a second pressure sensor 12 are installed between the outlet of the first water pump 9 and the second water pump 10 and the inlet of the boiler 1.

[0032] The temperature sensor 5, the first pressure sensor 6, the first flow sensor 7, the second flow sensor 11, and the second pressure sensor 12 are all electrically connected to the PLC controller 13.

[0033] The first water pump 9 and the second water pump 10 are electrically connected to the PLC controller 13, respectively.

[0034] The proportional control valve 8 is electrically connected to the PLC controller 13.

[0035] A water supply pipe 14 is provided between the first water pump 9 and the second water pump 10 and the boiler 1. The water supply pipe 14 includes pipe A and pipe B. Pipe A is an L-shaped pipe with the vertical section pointing upwards, and pipe B is an L-shaped pipe with the vertical section pointing downwards. The first water pump 9 and the second water pump 10 are sequentially arranged on pipe A. The vertical section of pipe B is connected to the horizontal section of pipe A and separates the first water pump 9 and the second water pump 10.

[0036] The vertical section of pipe A is connected to the horizontal section of pipe B, and the other end of the horizontal section of pipe B is connected to boiler 1.

[0037] The first water pump 9 is equipped with a frequency converter 15, which is communicatively connected to the PLC controller 13. The first water pump 9 is connected to the power supply through the frequency converter 15.

[0038] The second water pump 10 is equipped with a circuit breaker 16 and a relay 17. The second water pump 10 is connected to the power supply through the normally open contact of the circuit breaker 16. The coil of the circuit breaker 16 is connected to the normally open contact of the relay 17. The coil of the relay 17 is connected to the output terminal of the PLC controller 13.

[0039] The liquid level detection mechanism includes a water level electrode sensor 18, the output terminal of which is connected to the input terminal of the PLC controller 13;

[0040] The water level electrode sensor 18 is threadedly connected to the boiler 1.

[0041] The temperature sensor 5, the first pressure sensor 6, and the first flow sensor 7 are connected to the flange of the flue 2, and the flange on the transverse section of the pipe B is connected to the second flow sensor 11 and the second pressure sensor 12.

[0042] The PLC controller 13 is communicatively connected to the HMI module 19.

[0043] In this embodiment, the PLC controller 13 is an S7-200 Smart controller, and the HMI module 19 is a Smart700IEV3. The HMI module 19 stores automatic control programs for boiler pressure control, water shortage protection, overpressure protection, and over-temperature alarm within the PLC controller 13.

[0044] During operation, temperature sensor 5, first pressure sensor 6, and first flow sensor 7 monitor the flue gas temperature, pressure, and flow rate at the inlet of flue duct 2 in real time and transmit the data to PLC controller 13. Based on these parameters and the operating status of boiler 1 (such as water level and internal pressure), PLC controller 13 adjusts the opening of proportional regulating valve 8 (using PID control). When the flue gas temperature is high and the flow rate is large, providing more waste heat to boiler 1, PLC controller 13 controls proportional regulating valve 8 to increase its opening, allowing more high-temperature flue gas to enter flue duct 2 and exchange heat with the water in boiler 1, improving waste heat utilization efficiency. When the flue gas temperature is low and the flow rate is small, PLC controller 13 controls proportional regulating valve 8 to decrease its opening, reducing the amount of flue gas entering flue duct 2 and preventing parameters within boiler 1 from exceeding limits.

[0045] If a system malfunction occurs, such as boiler 1 running low on water (water level sensor 18 detects the water level is below the lower limit), PLC controller 13 will immediately issue a water shortage protection signal, triggering an alarm via HMI module 19. Simultaneously, it will control the first water pump 9 and the second water pump 10 to replenish water to boiler 1, preventing it from drying out. When the water level is within the normal range, PLC controller 13 starts the second water pump 10. The coil of relay 17 is energized, its normally open contact closes, energizing the coil of circuit breaker 16, closing its normally open contact, and powering on the second water pump 10. During water supply, the second flow sensor 11 and the second pressure sensor 12 monitor the water flow and pressure in the water supply pipe 14 in real time and transmit the data to PLC controller 13. PLC controller 13 adjusts the operating frequency of the first water pump 9 via frequency converter 15 according to preset flow and pressure thresholds. When the detected flow rate is lower than the set value or the pressure is insufficient, the PLC controller 13 controls the frequency converter 15 to increase the frequency of the first water pump 9, thereby increasing the water supply and pressure; conversely, it reduces the frequency to decrease the water supply and pressure, so as to ensure the stability of the water intake of the boiler 1.

[0046] The embodiments described above are merely preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the patent claims of this utility model should be included within the scope of the patent application of this utility model.

Claims

1. A PLC automatic control system for waste heat from a gas generator, comprising a boiler (1), the boiler (1) including an inlet, an outlet, a furnace, and a flue (2), a pump being installed at the inlet of the boiler (1), a liquid level detection mechanism being installed inside the boiler (1), and a valve being installed on the flue (2), and further comprising a PLC controller (13), characterized in that, A temperature sensor (5), a first pressure sensor (6), and a first flow sensor (7) are provided at the inlet of the flue (2). The valve includes a proportional regulating valve (8). The pump includes a first water pump (9) and a second water pump (10). The first water pump (9) and the second water pump (10) are respectively connected to the boiler (1). A second flow sensor (11) and a second pressure sensor (12) are provided between the outlet of the first water pump (9) and the second water pump (10) and the inlet of the boiler (1). The temperature sensor (5), the first pressure sensor (6), the first flow sensor (7), the second flow sensor (11), and the second pressure sensor (12) are all electrically connected to the PLC controller (13); The first water pump (9) and the second water pump (10) are electrically connected to the PLC controller (13) respectively; The proportional control valve (8) is electrically connected to the PLC controller (13).

2. The waste heat control system for a gas generator according to claim 1, characterized in that, A water supply pipe (14) is provided between the first water pump (9) and the second water pump (10) and the boiler (1). The water supply pipe (14) includes pipe A and pipe B. Pipe A is an L-shaped pipe with the vertical section pointing upwards, and pipe B is an L-shaped pipe with the vertical section pointing downwards. The first water pump (9) and the second water pump (10) are arranged sequentially on pipe A. The vertical section of pipe B is connected to the horizontal section of pipe A and separates the first water pump (9) and the second water pump (10). The vertical section of pipe A is connected to the horizontal section of pipe B, and the other end of the horizontal section of pipe B is connected to the boiler (1).

3. The waste heat control system for a gas generator according to claim 1, characterized in that, The first water pump (9) is equipped with a frequency converter (15), which is connected to the PLC controller (13) for communication. The first water pump (9) is connected to the power supply through the frequency converter (15). The second water pump (10) is equipped with a circuit breaker (16) and a relay (17). The second water pump (10) is connected to the power supply through the normally open contact of the circuit breaker (16). The coil of the circuit breaker (16) is connected to the normally open contact of the relay (17). The coil of the relay (17) is connected to the output terminal of the PLC controller (13).

4. The waste heat control system for a gas generator according to any one of claims 1, characterized in that, The liquid level detection mechanism includes a water level electrode sensor (18), the output terminal of which is connected to the input terminal of the PLC controller (13); The water level electrode sensor (18) is threadedly connected to the boiler (1).

5. The waste heat control system for a gas generator according to claim 2, characterized in that, The temperature sensor (5), the first pressure sensor (6) and the first flow sensor (7) are connected to the flange of the flue (2), and the flange of the transverse section of the pipe B is connected to the second flow sensor (11) and the second pressure sensor (12).

6. The waste heat control system for a gas generator according to claim 1, characterized in that, The PLC controller (13) is connected to an HMI module (19).

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