Boiler tube leakage monitoring system

1、 System Overview

With the development of power generation technology, modern power plant boilers have entered the era of large capacity and high parameters. The number of boiler tubes is increasing, and the reliability requirements in operation are also increasing. Once the boiler tube leaks, it will directly affect the safe and economic operation of the generator unit. Therefore, the early detection and timely treatment of boiler tube leakage is increasingly important for power generation enterprises. The automatic alarm device for boiler tube leakage uses acoustic wave measurement and signal processing technology to achieve early alarm for the leakage of the boiler's "four tubes" (water cooled wall tubes, superheater tubes, reheater tubes, and economizer tubes).

2、 Main components of the system

1. Signal acquisition system (including enhanced sensors and waveguides);

2. Host monitoring system;

3. Install auxiliary materials and communication cables.

3、 Working principle

The JN/XLB-2 boiler tube leakage alarm system utilizes the acoustic monitoring principle to collect various acoustic signals in the furnace through a specially designed enhanced acoustic sensor and convert them into current signals; On the basis of eliminating the noise interference caused by boiler operation, the frequency spectrum of the acoustic signal is obtained through fast Fourier transform technology analysis and displayed in bar graph form; By analyzing and calculating the noise intensity, spectrum characteristics, and duration, it is determined whether there is leakage in the furnace tube, as well as the location and extent of the leakage, so that the power station operators can take timely protective measures to prevent the expansion of the accident, shorten the repair time, and reduce economic losses. In addition, the device can effectively monitor the operating conditions of the soot blower.

4、 System Functions

1. Real-time leakage monitoring and early warning:

Since sand holes and cracks occur in the boiler tubes (water cooled walls, superheaters, reheaters, and economizers), the device will alarm level by level and accompanied by a light plate alarm; During the automatic monitoring of leakage, the colors displayed in the "real-time energy bar graph" indicate: normal (green), abnormal (orange), leakage (red), fault (dark red), and channel detection (blue).

2. Accurately locate the leak area:

Comprehensively determine the location of the leakage area based on the specific location of the leakage points, the leakage degree reflected by the "measuring points" distributed nearby, and the alarm sequence of each "measuring point"; An isolation range with a resolution of ≥ 4 meters, and the position of each measuring point can be calibrated.

3. Real-time display of leakage sound spectrum:

Display the spectrum diagram of the sound "heard" in the furnace at each measuring point, with a spectrum range of 2 to 15 kHz. It will clearly reflect the spectral characteristics of furnace tube leakage and steam soot blowing and acoustic soot blowing sounds.

4. Tracking leakage trends:

Display the sound development trend curve of each measurement point, reflecting the degree of furnace tube leakage. It also has recording and printing functions, and data storage time is 12 months.

5. Monitor and record the sound in the furnace:

You can optionally choose to monitor the sound in the furnace corresponding to a measurement point to reproduce the furnace sound scene.

6. Device self inspection and waveguide automatic ash removal:

Through the self check button, the system can automatically simulate the sound of furnace tube leakage. Through real-time energy bar graph, it can be very intuitive to determine whether each channel is working properly. The ash removal method for the waveguide can be selected from manual/automatic mode. When switching to automatic mode, a set time interval should be selected based on the combustion conditions of the boiler to regularly implement the ash removal operation for the waveguide.

7. Communication with DCS system:

This device provides multiple interfaces (RS232, LAN) to communicate with DCS, supports multiple standard protocols such as Modbus RTU, Modbus TCP, and supports multi-channel and multi-protocol simultaneous parallel transmission. Multiple units can share a leakage detection and alarm system.

5、 Technical parameters

Sensitivity: capable of detecting small leaks of 1-2 mm.

Resolution: The reasonable isolation range can reach a hemispherical range with a radius of 4 meters.

Continuous operation time: ≥ 20000 hours.

6、 Spare parts

1. Acoustic sensors: JN/XLB-2, ZD/XLB-2, XLB-2, etc.

    2. Monitor card: JN/XLB-3.

3. Acquisition cards: JN-9113, JN-818.

4. Switch value cards: JN-P8R8, JN-P16R16.

5. Acoustic conduit: