红外热像仪的应用：应用多台红外热像仪，划分5大区域进行监测，基本覆盖目前热风炉区域监测的重点区域。该系统具备24小时全方位监测功能，能实时监控设备表面温度，超温时精确定位并实时预警，实现自动预警、截屏、图表生成及云台控制。通过数据分析预警，有效预防事故，直观判断设备运转。系统支持多预置位、多监测区域设定，图形标识重点监测区，滤除干扰。可根据部件属性单独设置测温报警参数，实时计算温度变化，提高测温分析准确度。

系统功能：

1.可实时监测区域范围内每个坐标点的温度，并支持鼠标点选查看。可圈定区域监测温度范围。

2.自动预警，自定义温度预警设置，超限温度报警。

3.自动保存温度数据和视频，支持超分辨率回放及高低温追踪报警，一键生成报告。

现场安装图：

红外热像仪在钢包检测中的主要应用点

1、检测钢包及中间包的内衬

钢包内衬因受到化学侵蚀、机械冲刷和急冷急热，容易引起的裂纹、鼓包、脱落等。当耐火材料局部损毁严重而又未被发现时，将造成严重的漏钢事故。红外热像仪可以检测内衬的损毁状况，避免事故的发生。

2、检测钢包及中间包沉渣

沉渣不仅会降低钢水质量，而且容易堵塞出钢口，加速钢包耐火层的磨损，缩短设备的使用寿命。由于沉渣与钢水温度明显不同，通过红外热像仪实时输出温度图像，可以检测出沉渣位置。

3、检测钢水温度

由于钢包的恶劣环境和钢水的高温特性，传统的测温方式难以实时测量钢水温度。利用红外热像仪能对钢水温度进行实时、自动、连续测量并根据生成的温度曲线，分析钢水温度的变化趋势，直观地读出钢水的最高温度、平均温度，为生产管理和工艺改进提供有力的依据。

红外热像仪应用于钢包检测的独特优势

1、非接触、全天候实时监测，不影响钢包正常运行

2、测温区域内显示温度最高点、最高温度值、平均温度值，无需通过单点进行温度测量，方便操作人员读取

3、软件实现自动生成温度变化曲线记录，可对现场进行图像抓拍，显示加热温度情况

4、设备支持高温点报警，可多级设置报警阈值，达到设定温度点后输出报警信号。

Applicable Machine

Through timely understanding and mastering the charge level of the blast furnace throat and the distribution of gas flow, adjusting the blast furnace operation, maintaining the smooth and stable furnace condition, and improving various technical indicators, it plays an important role.

Technical introduction

The system is mainly composed of infrared thermal imager of blast furnace charge surface and protection and image processing device. The hardware structure diagram of the system is as follows:

System function

1. Real time monitoring the temperature distribution of the charge surface in the furnace before and after the distribution, as well as the distribution of materials;

2. Real time monitoring of the material level in the furnace before and after the distribution and the operation of the equipment in the furnace (such as distribution chute and feeler);

3. Multi point fixed-point temperature measurement and real-time temperature curve display;

4. It can directly measure the temperature of any point in the temperature image;

5. The temperature image at any time is stored in the way of hard disk storage, so as to query the historical data.

Main technical indicators:

Field angle: above 90 °

Spatial resolution: 5.1mard

Detector type: uncooled focal plane

Wavelength range: 8 ~ 14 µ M

Temperature measurement range: 15 ℃ ~ 2000 ℃

Accuracy: ± 2 ℃ or ± 2%

Working environment temperature: 0 ℃ ~ 60 ℃

Video interface: network interface

Applicable Machine

High air temperature is an important technical feature and development direction of modern blast furnace ironmaking. Increasing air temperature can effectively reduce fuel consumption and improve the efficiency of blast furnace energy utilization. A customer company owns two 5500m³blast furnace, each blast furnace is equipped with four BSK top burning hot stoves with a design air temperature of 1300 ° C.

1.1Problems in hot blast stove system

The hot blast system (hot blast stove body and pipe system) generally has the problem of high-temperature point cracking, and the frequency increases and the degree increases. The design specification of hot air system requires that the temperature of hot air stove body is less than 150 ° C, and the temperature of hot air duct is less than 200 ° C. However, there are many high-temperature points in the hot blast stove body and hot blast pipe, such as 2^# stove. The average detection temperature of the embedded thermocouple (16 points) in the hot blast stove body is 128 ° C, of which the temperature of 5 points is > 150 ° C. Statistics show that the hot blast furnace shell cracked 57 times in 2014, 30 times in 2015 and 58 times in 2016, and the cracking parts are mainly concentrated in 14-16 zones. After the bellows of the hot air system was put into operation, high temperature points (the design temperature is less than 200 ° C) and cracks occurred successively. As shown in Figure 1.

1.2Limitations of manual inspection

The blast furnace hot blast stove (shell and piping) belongs to the ultra-high temperature area (internal hot blast temperature 1400 ° C), and the weak points crack to varying degrees under high temperature, which has great potential safety hazards. The blast furnace hot air system has no prediction or feedback measures and means, and only relies on routine manual inspection every 2h. There are two problems in manual patrol inspection: ① due to the limitation of site and time, there are great limitations and contingencies. The inspection route is affected by the platform, the distribution of high temperature points and the uncertainty of inspection time, so the status of hot blast stove shell cannot be monitored comprehensively and all-weather; ② The cracking of the furnace shell is sudden, and the safety of the inspectors cannot be guaranteed, so there are great potential safety hazards. In order not to affect the normal production and operation of blast furnace hot blast stove, the primary task is to comprehensively, in detail and in real time monitor the unsafe factors of the existing hot blast system, and process the monitoring data information, so as to control the hot blast system within the safe operation range.

2.Development of infrared imaging monitoring system for hot blast stove

2.1Infrared imaging system of hot blast stove

The infrared imaging monitoring system of the hot air system is equipped with 15 temperature monitoring points, including 9 temperature monitoring points of the hot air furnace shell and 6 hot air piping monitoring points. Considering the cost, after site investigation, it is proposed to set five fixed thermal imager temperature measurement points and another mobile temperature measurement point. The monitoring pictures of each infrared thermal imager are transmitted to the monitoring computer in real time through optical fiber. The computer displays the picture online, establishes a database at the same time, automatically analyzes and processes the data of monitoring points, draws the temperature change curve of each region, and gives the temperature change rate of each region and the alarm of abnormal points. As shown in Figure 2.

2.2Principle of infrared imaging system for hot blast stove

According to the principle that the infrared intensity is different under different temperatures of the object, the infrared thermal imager uses the infrared detector and optical imaging objective lens to receive the infrared radiation energy distribution pattern of the measured object and reflect it on the photosensitive element of the infrared detector, so as to obtain the infrared thermal image. This kind of thermal image corresponds to the thermal distribution field on the surface of the object, and the temperature distribution in different areas of the measured object is obtained by conversion. The data measured by the infrared thermal imager is transmitted to the computer system. The computer software integrates, analyzes and processes the data, obtains useful information, and presents it to the operator through a simple and clear interface. Using infrared imaging equipment to complete the test work has the advantages of all-weather and wide coverage. Figure 3 shows the infrared imaging monitoring diagram of hot blast stove.

2.3Development of infrared imaging system for hot blast stove

Main objective: to develop infrared imaging monitoring technology for blast furnace hot air system. Main research contents: ① hardware and network architecture scheme and implementation; ② Program code writing and software system development.

The functions to be realized or satisfied by the infrared imaging technology of the hot air system: ① monitoring function, the monitoring range of the hot air system in the suspicious area, continuous monitoring in time sequence, and reliable trend and high accuracy in the monitoring results of the surface temperature; ② For the alarm function after reaching a certain temperature, according to the design specifications, the hot air duct ＜ 200 ° C, the hot air stove body 150 ° C, according to the degree close to the temperature, carry out warning or alarm, and give the location of the warning area (accuracy 0.5m); ③ For parts or areas that exceed the design specifications, in addition to the above temperature monitoring data, video data information for a period of time can be recorded and played back; ④ The system should have strong compatibility and redevelopment. The research and development of infrared imaging technology is applied to practical production to ensure the safe and stable operation of large blast furnace hot air system.

3.Application of infrared imaging monitoring system for hot blast stove

3.1Architecture of infrared imaging monitoring system for hot blast stove

According to the layout and internal equipment connection of 4 hot blast furnaces of 1^# blast furnace, in order to realize the temperature measurement monitoring coverage of the hot blast furnace shell (14-16 belts) and hot blast pipe system (hot blast branch pipe and hot blast main pipe), five fixed thermal imager temperature measurement points and one mobile temperature measurement point are set after field investigation. As shown in Figure 4, probe 1 is under the viaduct of the blast furnace control room; Probe 2 is on the top platform of blast furnace gas bag dedusting system; Probe 3 is at the east end of the East-West Center Line on the hot blast stove frame; Probe 4 is at the center point of the East-West Center Line on the hot blast stove frame; Probe 5 is at the west end of the East-West Center Line on the hot blast stove frame.

Each point thermal imager is equipped with an automatic rotating PTZ, in which probe 1 and probe 2 are supported PTZ, and probe 3, probe 4 and probe 5 are suspended PTZ. Through the rotation of each PTZ, the thermal imager can realize the regular scanning or fixed-point monitoring of all monitoring target areas. According to the monitoring results of each fixed point, the setting point of the mobile infrared thermal imager sets the mobile infrared thermal imager at a short distance for continuous monitoring when the most dangerous area is blocked by pipes or equipment around and cannot be directly monitored by the fixed probe.

The monitoring picture of infrared thermal imager is transmitted to the monitoring computer in real time through optical fiber. The computer displays each picture online, establishes a database at the same time, automatically analyzes and processes the data of the monitored points, draws the temperature change curve of each area, and gives the alarm of the temperature change rate and abnormal points of each area.

3.2Problems and solutions in the application of infrared imaging monitoring system

(1) The infrared radiation emission characteristic of the material itself is the key to the accurate temperature measurement of the hot blast stove shell by the thermal imager. In the previous hot blast stove test, it was found that the temperature measured by the thermal imager in different areas of the same equipment was different at the same temperature. The reason for analysis is that the emissivity of different surface materials of the equipment is different, and the infrared radiation energy is different. When the temperature of the whole monitoring object is converted with a fixed emissivity, a large error will occur.

Solution: ① investigate the infrared emissivity of different materials (base metal steel plate, weld material, antirust paint, etc.) on the surface of hot blast stove shell; ② The contact surface thermometer is used to measure the surface temperature of representative areas of different materials, and the infrared emissivity of different material areas is determined by comparing with the temperature measurement of infrared thermal imager; ③ The monitoring area of each measuring point is set with different infrared emissivity to obtain the accurate thermal imaging monitoring temperature of the area; ④ Regularly use the contact surface thermometer for local inspection and correction to ensure the long-term accuracy of the temperature measurement results of the infrared thermal imager.

(2) Setting of measuring points of infrared thermal imager. Each blast furnace has 4 hot blast stoves, which are arranged in a staggered rectangle. The on-site investigation found that, except for the relatively open and unobstructed north side, there are many devices around the other three sides, so it is difficult to find a fully covered installation point of the infrared thermal imager. The equipment area for close monitoring is limited. In addition, the internal pipelines and valves of the four hot blast stoves are densely covered, and there is no directional installation point that can cover all the monitoring areas.

Solution: realize full coverage monitoring in all areas by setting multiple measurement points and adopting the method of rotating pan tilt. The scanning frequency of the automatic rotating pan tilt to the monitoring area also fully meets the monitoring requirements. For the partially sheltered area, by comparing the temperature changes in the surrounding monitoring area and directly measuring with the surface thermometer, if it is considered to be a dangerous area, a movable infrared thermal imager is set for online monitoring.

(3) Data analysis and processing. The multi-point infrared thermal imaging thermometer set in the system will generate massive data in real time, and the change of hot blast stove shell state is a relatively slow and continuous process. Therefore, the computer system is required to screen and compare massive data, obtain the required parameters and change process of key parts, and accurately predict the change trend and possible risks.

Solution: according to the monitored hot blast stove shell area, establish the corresponding database. Develop temperature data to ensure the accuracy and representativeness of monitoring data and processing results.

4.Epilogue

The infrared imaging monitoring system of blast furnace hot blast stove is based on the principle that the infrared thermal imager is based on the different intensity of infrared radiation under different temperatures of the object, and uses the infrared detector and optical imaging objective lens to receive the infrared radiation energy distribution pattern of the measured object and reflect it on the optical sensor of the infrared detector, so as to obtain the infrared thermal image, which corresponds to the thermal distribution field on the surface of the object, The temperature distribution in different areas of the measured object is obtained by conversion. The data measured by the infrared thermal imager is transmitted to the computer system. The computer software integrates, analyzes and processes the data, obtains useful information, and presents it to the operator through a simple interface. The infrared imaging monitoring system can monitor and analyze data changes, prevent and alarm the cracking of the hot blast stove shell and hot blast pipe. It is suitable for the hot blast stove system of iron making blast furnace, realize real-time monitoring and data analysis, replace the inspectors in the dangerous area of the hot blast stove, eliminate potential safety hazards, and ensure safe production.

Applicable Machine

K23E5 online infrared thermal imaging thermometer adopts 17 μm uncooled infrared focal plane detector, high-performance infrared lens and signal processing circuit, and embedded image processing algorithm, with small size, low power consumption, fast start-up, excellent imaging quality, accurate temperature measurement and other characteristics.

The device selection of k23e5 on-line infrared thermal imaging thermometer fully considers the requirements of high and low temperature working performance to ensure that the whole machine has excellent environmental adaptability.

Functional Characteristics

1. It has all-weather passive thermal imaging function, has strong smoke penetration performance, and can be used in a wide range of ambient temperatures;
2. With high frame rate design, fast-moving targets can be observed;
3. Adopt self-developed temperature measurement correction algorithm to realize accurate temperature measurement;
4. The full stream lossless 16bit temperature data is output, and the client software and SDK development kit are provided to facilitate the secondary development and system integration of customers, and fully carry out personalized temperature analysis of the tested target.

Application Field

Power Grid, Petroleum And Petrochemical, Rail Transit, Circuit Detection

Scientific Research, Security Monitoring, Machine Vision, Customized Development