锌挥发回转窑|锌冶炼回转窑工作原理就是煅烧锌、处理含锌物的整个过程和原理。一般多采用氧化锌回转窑处理含锌的滤饼。滤饼中的锌主要以铁酸锌、氧化物和硫酸盐形态存在，在氧化锌回转窑的高温下，铁酸锌和固体碳作用，还原为金属锌，同时锌、铅、镉的硫酸盐也被还原，井以硫化物和金屈形态挥发出来。从固相中还原和挥发出来的金属，在窑气氛作用下，又重新氧化，最后主要以氧化物形态产出。

锌挥发回转窑红外解决方案：

HIRDA-NK-A系列内窥式气动超高温红外热成像温度检测与分析系统，为锌挥发回转窑温度监控，提供了一整套全面的解决方案。

安装图：

HIRDA-NK-A系列内窥式气动超高温红外热成像温度检测与分析系统由红外热成像机芯、耐高温红外热成像镜头、自动回缩保护装置、炉壁安装套件、空气过滤系统和现场设备箱、算法服务器以及智能测温软件等组成。

将耐高温红外热成像镜头安装在能够伸缩的金属防护罩中，通过伸缩装置将耐高温红外热成像镜头直接伸入至窑炉内（1600℃以下），红外热成像机芯停留在炉外，实现对窑内运行工作状态的连续实时监视。

通过压缩的冷却空气或冷却水，对护罩进行冷却，使红外镜头工作在较适宜的温度；同时对镜头进行吹扫，防止炉内灰尘附着在镜头保护窗口上；系统内置高温保护电路，一旦冷却气体或冷却水发生循环异常，即回缩镜头，防止被窑内高温损伤。

具有耐高温、耐腐蚀、免维护的特点，能够实时显示窑炉内部各种复杂的工况，在摄像探头吹扫压缩空气正常的情况下，适用于各种正压窑炉。

系统特点：

• 具备全天候被动红外测温功能
• 采用自研测温校正算法，实现精确温度测量
• 支持onvif协议，可接入主流NVR；
• 不依赖系统平台，可直接网页登录ip进行访问图像和配置，可直接输出报警信号到PLC或者报警器；
• 伸缩长度可定制，适合各种壁厚的窑炉
• 螺旋风幕设计，镜头不积灰
• 整体不锈钢材料，耐腐耐温
• 直视型内窥镜头
• 自动退出保护装置, 退出故障指示
• 气动传动机构
• 耐高温光学针孔镜头，带防尘高温镜片
• 超温、欠压、停电自动退出炉膛

铝灰(渣)在潮湿的空气中易发生反应生成氨气、甲烷、氢气等有毒、有害、易爆气体，是一种需要及时处理的危险固体废弃物。铝灰中含有铝单质、氧化铝、碳化铝、硅、氟化物、氯化物等成分。其中，氧化铝占70%以上，具有较高的回收利用价值。铝灰回转窑工艺流程处置二次铝灰主要是由高温煅烧，使铝灰和石灰石高温发生反应，生成铝酸钙。温度控制对于生产具有非常重要的作用。

HIRDA-NK-A系列内窥式气动超高温红外热成像温度检测与分析系统，为铝灰回转窑温度监控，提供了一整套全面的解决方案。

系统简介：

HIRDA-NK-A系列内窥式气动超高温红外热成像温度检测与分析系统由红外热成像机芯、耐高温红外热成像镜头、自动回缩保护装置、炉壁安装套件、空气过滤系统和现场设备箱、算法服务器以及智能测温软件等组成。

安装图：

将耐高温红外热成像镜头安装在能够伸缩的金属防护罩中，通过伸缩装置将耐高温红外热成像镜头直接伸入至窑炉内（1600℃以下），红外热成像机芯停留在炉外，实现对窑内运行工作状态的连续实时监视。

通过压缩的冷却空气或冷却水，对护罩进行冷却，使红外镜头工作在较适宜的温度；同时对镜头进行吹扫，防止炉内灰尘附着在镜头保护窗口上；系统内置高温保护电路，一旦冷却气体或冷却水发生循环异常，即回缩镜头，防止被窑内高温损伤。

具有耐高温、耐腐蚀、免维护的特点，能够实时显示窑炉内部各种复杂的工况，在摄像探头吹扫压缩空气正常的情况下，适用于各种正压窑炉。

系统特点：

• 具备全天候被动红外测温功能
• 采用自研测温校正算法，实现精确温度测量
• 支持onvif协议，可接入主流NVR；
• 不依赖系统平台，可直接网页登录ip进行访问图像和配置，可直接输出报警信号到PLC或者报警器；
• 伸缩长度可定制，适合各种壁厚的窑炉
• 螺旋风幕设计，镜头不积灰
• 整体不锈钢材料，耐腐耐温
• 直视型内窥镜头
• 自动退出保护装置, 退出故障指示
• 气动传动机构
• 耐高温光学针孔镜头，带防尘高温镜片
• 超温、欠压、停电自动退出炉膛

窑在旋转过程中的可能发生弯曲和扭转会损坏耐火材料，必须进行修复，修复过程涉及耐火材料的浇注。否则，在定期维护期间需要更换耐火材料。

在某些场景，可以根据窑的外表面温度来确定内部耐火材料的厚度。这其中涉及许多未知因素，包括表面发射率、传热变化、材料温差和燃烧器火焰影响。估算衬里厚度时必须考虑这些因素。

HJK-FBTS-XC在线式防爆红外热成像监控系统通过卓越的性能提供准确的温度数据，为了衬里耐火材料厚度的计算助力。

HJK-FBTS-XC在线式防爆红外热成像监控系统功能特性：

1. 采用非制冷焦平面探测器、高性能红外镜头、型号处理电路、并嵌入先进的图像处理算法，具备功耗低、启动快速、成像质量优异、测温精准等特点；
2. It has all-weather passive thermal imaging function, has strong smoke penetration performance, and can be used in a wide range of ambient temperatures;
3. Adopt self-developed temperature measurement correction algorithm to realize accurate temperature measurement;
4. 防护罩采用耐高温合金材料制成，具有耐腐蚀、耐高温性能。窥孔直径2mm，在冷却介质及风吹扫后，在耐高温、防粉尘等性能方面更为优良，大大提高使用寿命。
5. 在镜头前采用多道风屏，既可以起到降温的作用，更重要的作用是挡去了窑内的飞砂、熔融物等，使镜头不受污染和侵蚀，保持图象永久清晰。
6. 对压缩空气采用空气净化器，始终保持镜头无污，保证图像清晰。
7. 具有断水、断气、断电、温度高自动退出功能。
8. 全自动进入功能，气压压力、水流量、高于设定值，温度低于设定值，探头自动伸进窑炉监测炉内情况。

整个窑炉的温度分布监控对于水泥质量至关重要。它还可以通过在早期阶段检测耐火材料或未充分淬火的熟料来帮助延长窑炉的使用寿命——如果不加以控制，可能会导致生产停顿。

窑炉内的条件使得温度分布监控变得困难。窑炉旋转、高温以及烧结材料沿窑炉的移动使得热电偶和其他接触式温度传感器不太好用。非接触式温度测量方式就显得非常有价值。

HJK-FBTS-XC在线式防爆红外热成像监控系统（非接触式温度测量方式）位于燃烧器下方和侧面的窑头罩的观察口可以最好地测量熟料温度，这个位置温度高，粉尘大，设备配套水冷装置，以防止损坏设备。

HJK-FBTS-XC在线式防爆红外热成像监控系统功能特性：

1. 采用非制冷焦平面探测器、高性能红外镜头、信号处理电路、并嵌入先进的图像处理算法，具备功耗低、启动快速、成像质量优异、测温精准等特点；
2. It has all-weather passive thermal imaging function, has strong smoke penetration performance, and can be used in a wide range of ambient temperatures;
3. Adopt self-developed temperature measurement correction algorithm to realize accurate temperature measurement;
4. 防护罩采用耐高温合金材料制成，具有耐腐蚀、耐高温性能。窥孔直径2mm，在冷却介质及风吹扫后，在耐高温、防粉尘等性能方面更为优良，大大提高使用寿命；
5. 在镜头前采用多道风屏，既可以起到降温的作用，更重要的作用是挡去了窑内的飞砂、熔融物等，使镜头不受污染和侵蚀，保持图象永久清晰；
6. 对压缩空气采用空气净化器，始终保持镜头无污，保证图像清晰；
7. 具有断水、断气、断电、温度高自动退出功能；
8. 全自动进入功能，气压压力、水流量高于设定值，温度低于设定值，探头自动伸进窑炉监测炉内情况。

回转窑是水泥厂的核心设备；其工作状况直接影响水泥厂的生产效率和熟料质量。为了使回转窑保持良好的工作状态，我们必须学会在日常生产中如何正确维护回转窑。回转窑的维护有一些注意事项和说明。

水泥回转窑可能出现的故障有：

1. 窑筒在长期的过程中可能会出现径向摆动变大，导致窑尾漏料严重的情况；
2. 熟料生产过程中窑筒上下运动不受控制，会影响托辊、轮带的稳定性和使用寿命；
3. 大齿轮、托辊振动异常，窑轮传动频繁振动，影响正常生产；
4. 回转窑耐火衬砖经常开裂、脱落；
5. 熟料生产过程中，窑的传递扭矩和各轮带支撑轴的承载力发生意外变化。

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

随着回转窑的使用时间不断增加，内衬在高温不断的侵蚀和熟料的摩擦下会导致内衬变薄甚至脱落，人工巡检过程中很难准确发现异常区域，同时由于熟料颗粒太细，粉料过多易结块，在窑体中间部位靠近窑头方向极易导致内衬结圈，结圈堆积过深会影响熟料的正常下滑，造成熟料过烧乃至影响熟料品质。因此建设一套实时监测回转窑状态的诊断分析系统尤为关键。

二．解决方案

本系统基于红外测温技术设计，进行回转窑窑体运行状态监测分析，系统给用户提供窑体温度的分布、各区域温度变化趋势等关键数据，能够为用户分析回转窑健康状态、调节球团煅烧工艺带来极大帮助。

系统可自动获取回转窑平铺图，“分段式”自动分析回转窑截面的温度分布情况，自动形成温度变化趋势图。

三．窑体温度成像系统

窑体热成像系统附带高配热像镜头监控所有高温工艺的流程,结合实时和存储的回转窑关键数据,扫描仪为全窑温、耐火砖提供精确的测量:监视事件的演变，绘制趋势,安排预防性维护操作。

1. 全天候将前端热像仪采集的全辐射红外图像流接入中控室,实时显示转窑运行状态。
2. 根据回转窑内的燃烧过程在表面壁温不同，划分干燥、热解、燃烧、燃尽各种所需区域。
3. 在实时画面中查着炉窑各个区域最高温度值,分析定位转窑内部结焦或耐火泥脱落位置与状态,尽早预警每一个热点的形成及其发展。
4. 对实时画面储存备查,显示各区域位置最高温与颜色,根据数据处理完成的高温带变化超限报警,显示燃烧中心位置变化并用于指导调整进料与燃烧控制。
5. 系统具备自检功能,故障后自动重新连接,支持远程故障处理,保证系统稳定可靠运行。

Applicable Machine

KD series online infrared thermal imaging thermometer adopts 17 μ M uncooled infrared focal plane detector, high-performance infrared lens and signal processing circuit, and embedded with advanced image processing algorithm, it has the characteristics of small size, low power consumption, fast startup, excellent imaging quality, accurate temperature measurement and so on.

The device selection of KD series 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

Iron And Steel Metallurgy, Petroleum And Petrochemical, Rail Transit, Scientific Research

Power Grid, Machine Vision, Customized Development

Current situation and demand analysis of rotary kiln

As the core facility in the cement production process, the combustion temperature in the kiln and the outer wall temperature of the barrel are very important to the product quality and production safety. Through on-site investigation and communication, the existing risks are as follows:

• The firing temperature in the rotary kiln directly affects whether the reaction is complete and effective. The reaction temperature is too low, the clinker quality is poor, the rotary kiln is forced to slow down, and the unit heat consumption increases.
• The firing temperature of dense rotary kiln is too high, which is easy to burn out the kiln lining materials and affect the long-term safe operation of the kiln.
• Because the clinker is easy to agglomerate, it is very easy to cause ring formation, and the ring is stacked at the tail, which affects the product quality, so that the kiln needs to be stopped for coke removal, which affects the reliability of equipment operation.
• The internal refractory materials gradually erode and fall off, and the steel plate will be directly exposed to the high temperature environment, softening and even melting corrosion, which will seriously threaten the production safety and cause unplanned kiln shutdown or accident.
• When the fuel is burned in the rotary kiln, due to the structural characteristics of the rotary kiln, it is impossible to take direct means to measure the internal temperature distribution, and it is impossible to judge the location of the combustion center and the internal temperature condition, which will cause insufficient combustion or excessive combustion.

In order to ensure the safe and efficient operation of the rotary kiln, an effective online temperature monitoring system is urgently needed for the areas inside and outside the rotary kiln, so as to improve the safety of the production process and the ability of risk early warning. The monitoring system shall meet the following requirements:

• Carry out non-contact temperature measurement, and comprehensively and accurately monitor the temperature at the kiln head and outside the kiln, so that the normal operation of the kiln will not be affected during the operation of the equipment.
• High stability and applicability: the monitoring equipment in the kiln can work stably under high temperature conditions, and the temperature measurement range covers the normal and abnormal temperatures in the kiln. The monitoring equipment outside the kiln can monitor the whole rotary kiln barrel;
• Risk warning and high temperature alarm: it can realize rapid alarm for high-temperature objects;
• Data storage: it can trigger video storage in the whole process or alarm, and can query and playback previous historical images;
• The power supply ensures the uninterrupted power supply of the system in an all-weather environment.

Characteristics of infrared monitoring system for rotary kiln

1. High performance infrared thermal imager

For the high temperature environment in the kiln, the temperature measurement range of the thermal imager is up to 1600 ℃; The thermal imager outside the kiln has large field angle and wide coverage, which meets the needs of cylinder monitoring

2. Collect temperature flow around the clock

The collected full radiation infrared image stream is connected to the central control room all day, and the temperature distribution, the highest temperature, the lowest temperature and the average temperature in each area of the rotary kiln are checked in the real-time picture

3. Five abnormal temperature alarms

You can customize the alarms of overtemperature, high temperature range, temperature, temperature range and outside the temperature range. Five types of alarms are pushed by wechat or SMS, and the alarms are timely sent to the relevant person in charge for action

4. Draw the temperature change curve in real time

Draw the temperature change curve of the rotary kiln in real time, and display the trend diagram of the highest temperature change at each position of the cross section and longitudinal section of the outer wall, so as to provide a reference for analyzing the position and state of internal coking or refractory mud falling off

5. Record the temperature distribution of kiln wall tiling

The system can record the temperature distribution after the expansion of the outer surface of the kiln wall every week, and display the maximum and minimum temperature values in different areas in this week

6. The rotary kiln distance identification point can be set

Different distance identification points of the rotary kiln can be set in the picture to indicate the actual position of the area on the rotary kiln, so that the observer can better identify the abnormal temperature points

7. Automatically generate the highest temperature curve

Automatically generate the highest temperature change curve of the region 'to guide the adjustment of the position of the combustion Center

8. User permissions can be set

In order to facilitate user management, the system can set the permissions of different personnel

9. Automatic reconnection after failure

System self inspection, automatic reconnection after failure, support remote fault handling, and ensure stable and reliable operation of the system

Inner wall monitoring function

Video display is mainly used, including burner flame shape monitoring, regional temperature extreme value display, pellet movement track monitoring in the kiln, ring position and shape display, and corrosion resistance display. The temperature at any point in the picture can be obtained through the mouse, and the monitoring video can also be recorded.

Outer wall monitoring function

The monitoring function of the outer wall of the rotary kiln includes the distance marking function of the outer wall of the rotary kiln, the temperature of any point in the picture can be obtained through the mouse, and the monitoring video can also be recorded.

Outer wall data analysis function

In order to facilitate users to have an intuitive understanding of the temperature of the whole kiln barrel, huajingkang has exclusively developed the all-weather three-dimensional continuous monitoring technology of the outer wall temperature of the rotary kiln.

The infrared continuous three-dimensional measurement technology of the surface temperature of the outer wall of the rotary kiln combines the positioning technology of the temperature measuring point of the kiln body, the system temperature compensation technology and the infrared thermal imager 'to display the temperature distribution of the kiln body in real time during the operation of the rotary kiln, so as to realize the all-weather three-dimensional continuous monitoring of the rotary kiln, directly display the temperature information in the axial and circumferential directions during the operation of the kiln body, and display the specific temperature value at any position of the outer wall of the kiln at the same time. The temperature distribution cloud map of the outer wall of the kiln unfolds the surface of the kiln body, which can display the temperature distribution of the outer wall in real time when the kiln body rotates for one cycle. The system can take out the maximum and minimum values of the temperature in the axial and circumferential directions of the kiln body for separate display, and display the temperature extreme value in the circumferential direction at the specific position of each meter. In the software, the temperature of the kiln barrel can be displayed from the cross section and longitudinal section, and the on-site operators can judge the position of the high temperature zone, the position of the formation of the ring and the position of the falling off of the refractory in the kiln, so as to provide a visual reference for the on-site production.

Applicable Machine

1. Application status of thermal imaging technology in rotary kiln inspection

At present, rotary kiln is an important equipment in metallurgy, building materials, chemical plants and silicate industry in China. According to relevant statistics, more than 60% of the kiln stoppages are caused by the damage of the kiln lining. The lining of the rotary kiln is mainly composed of refractory bricks. The refractory bricks rub against the materials for a long time and are in a high temperature state, which will lead to the deformation, serious wear and tear of the refractory bricks and even the falling of the bricks. This not only affects normal production, but also wastes energy and increases production costs. The on-line monitoring technology of the surface temperature of the rotary kiln enables the on-site staff to timely understand the temperature in the kiln and the changes of refractory materials, and arrange maintenance personnel to repair according to the actual situation, which greatly improves the efficiency and accuracy of production equipment fault detection.

2. Application requirements of rotary kiln for thermal imaging technology

2.1 working characteristics of rotary kiln

The rotary kiln is composed of cylinder, transmission device, supporting device such as supporting wheel and runner, sealing device at kiln head and tail, kiln head cover and combustion device. The barrel of rotary kiln is a heated rotary part, and the barrel is equipped with temperature measurement and sampling hole devices. Some kilns also need to be specially equipped with infrared thermometer to monitor the temperature of the barrel surface. Infrared imaging technology has been applied to the temperature measurement of materials in rotary kiln and the surface temperature detection of rotary kiln.

2.2 Routine maintenance methods and means of rotary kiln

For the maintenance of rotary kiln, the current practice is to strictly implement the regular overhaul system. According to the operating regulations, the refractory bricks should be replaced every 150 days of operation, while the actual operation can reach about 210 days. For the inspection between the two intermediate repairs of the rotary kiln, the conventional method is that the inspection workers use the hand-held temperature measuring instrument, combined with their inspection experience, to measure the temperature of the part of the rotary kiln that may be damaged, and then record and repair the rotary kiln with abnormal temperature. This method mainly relies on the experience of the testing workers to measure the temperature at a limited point, rather than the overall measurement of the rotary kiln. Therefore, it has certain limitations, randomness and is easy to miss the inspection.

Maintenance difficulties

The volume of the rotary kiln is large and it is rotating all the time. Moreover, the inspection workload of maintenance workers is large, and the time of one inspection is also relatively long. Similarly, sometimes the failure to repair in time due to faults will also lead to accidents and serious consequences. In view of this situation, various online monitoring means are being strengthened, the regular overhaul system is being reformed, and the transition to predictive maintenance system is gradually underway. Infrared thermal imaging is one of the important online monitoring means.

2.2 Advantages of infrared thermography detection of rotary kiln

The infrared thermal imager can quickly and conveniently obtain the two-dimensional thermal image of the outer wall of the rotary kiln, that is, the surface temperature field of the outer wall. Due to the obvious difference in heat conduction between the outer metal and the inner non-metallic materials of the rotary kiln, the degree, type and distribution of lining damage are the direct reasons for the different distribution of temperature field on the outer wall surface of the rotary kiln. Therefore, the main defects of the inner lining can be reflected in different degrees in the infrared image.

The damage types of rotary kiln lining can be roughly divided into thinning, cracking, bulging and falling off. Although the strict theoretical relationship between each type of damage and infrared thermogram has not been established, through the analysis of infrared thermogram and the comparison of lining inspection, the infrared spectrum of each type of defect has its own characteristics. For example, in terms of shape, for the crack type damage corresponding to the general long strip or slender overtemperature zone, when the maximum temperature of the overtemperature zone is greater than a certain value, it can be diagnosed as through crack damage; When the temperature is moderate, it may be a general crack. If the average temperature in the overtemperature zone exceeds a certain value, it can generally be diagnosed as falling off damage; If the average temperature in the overtemperature zone is lower than a certain value and the temperature gradient is small, it can generally be diagnosed as thinning.

It is a scientific and effective means to analyze, judge and inspect the working state of the internal lining through the on-line non-contact infrared thermal image test of the temperature field on the outer surface of the rotary kiln by using the infrared thermal image, which can provide a practical basis for ensuring the long-term operation of the rotary kiln.

2、 Current situation of infrared thermography and temperature measurement of rotary kiln

1. Use the hand-held thermal imager to regularly detect the rotary kiln

At present, the handheld thermal imager has been widely used in the steel industry. For example, the hand-held thermal imager is used to identify the blockage of steam pipes and hot water pipes and find the blockage point; Conduct regular maintenance of high-voltage electrical equipment to detect whether the contacts of such equipment are overheated; It can also detect the parts of some rotating (moving) equipment that are heated due to friction. Production equipment in iron and steel enterprises, including blast furnaces, hot blast stoves, hot blast pipes, heating furnaces, soaking pits, various steel-making furnaces, etc., are high-temperature service equipment with refractory lining, just like rotary kilns. Handheld thermal imagers have also been widely used in the maintenance of such equipment to judge the damage degree of refractory materials and play the role of preventive maintenance.

The infrared and visible light pictures taken by the hand-held thermal imager use the hand-held infrared thermal imager to detect the rotary kiln, mainly for the regular maintenance of the rotary kiln. The maintenance personnel regularly go to the site to observe the rotary kiln. First, store the thermal image in the memory card of the thermal imager, and then use the computer to read and analyze the collected pictures to form a report. This report is also mainly used for auxiliary positioning during intermediate repair of rotary kiln. Therefore, it is limited to use the hand-held thermal imager to regularly detect the rotary kiln:

1) When analyzing the infrared thermal image of the rotary kiln, the general analysis software is used, which does not combine the infrared spectrum characteristics of the lining damage of the rotary kiln. The judgment of the defect points mainly depends on the experience of the maintenance personnel. Therefore, the defects that can be confirmed by the maintenance personnel are often more serious damage, and usually they cannot give more specific information about the type and degree of damage;

2) Because it is a periodic inspection, the discovery of defects also has a certain contingency, which can not completely avoid the occurrence of major accidents;

3) The work of manual maintenance is complex, and the workload of using infrared thermal imager to overhaul all rotary kilns in use is very large. If it is overhauled in stages and batches, the overhaul interval will be extended, which is not conducive to the timely treatment of major damage to the lining of the rotary kiln.

2. Scanning rotary kiln infrared thermal image detection system

The infrared thermal imager is installed on the tracks on both sides of the rotary kiln, and the infrared scanner reciprocates in the x-axis direction at the same time during the scanning process. From the working principle of scanning imaging, it can be seen that the infrared scanner needs to move back and forth before the system can detect the complete imaging of the rotary kiln. Moreover, when the rotary kiln and infrared scanner move at a uniform speed as far as possible, the proportion of the infrared thermal image obtained is consistent with the physical proportion of the rotary kiln, that is, the imaging does not deform.

From this, we can see the limitations of scanning imaging. Without the intuition and reality of focal plane imaging, the image details are not clear enough, that is, the resolution of temperature is not enough.

Infrared thermographic detection system for rotary kiln

After site measurement, the site dimensions are as follows:

Rotary kiln size: 70000 ×Φ 4200mm；

Site installation distance: 15000mm;

Parameters of infrared thermal imager are as follows:

It is calculated that the maximum length of the observation object of the infrared thermal imager is 17000mm, and the length of the rotary kiln to be monitored is about 62000mm. To monitor the whole rotary kiln, it is necessary to take periodic infrared photos of the rotary kiln at least at four preset positions. The detection system has two schemes, which are introduced in detail below.

Programme1 Install an infrared thermal imager, configure the track for the infrared thermal imager, and use the track control system to stop the infrared thermal imager at the specified position and take photos periodically. The site installation diagram and system structure diagram are shown in the following pages.

Installation diagram

System structure diagram

If this scheme is adopted, the whole system is composed of infrared image acquisition system, slide motion control system and infrared back-end analysis system. The infrared image acquisition system is composed of an infrared thermal imager and a network access system to realize the infrared image acquisition and transmission function of the rotary kiln; The slide rail motion control system is composed of motor, motor driver, sensor, slide rail and motion controller to realize the positioning function of the rail car; The infrared back-end analysis system is composed of server and analysis software to complete the storage and analysis of surface temperature field data of rotary kiln.

Programme2Three infrared thermal imagers with pan tilt are installed. Each infrared thermal imager is equipped with three prefabrication positions, and the three infrared thermal imagers monitor the surface of the whole rotary kiln. The site installation diagram and system structure diagram are as follows.

If this scheme is adopted, the whole system is composed of infrared image acquisition system, pan tilt control system and infrared back-end analysis system. The infrared image acquisition system is composed of three infrared thermal imagers, PTZ and network access system. The infrared image acquisition system and the infrared back-end analysis system have the same functions and scheme I.

The thermal imagers of the two schemes are installed on the side of the rotary kiln. Since the rotary kiln itself rotates continuously (generally, the rotation speed is 0.5~2 RPM), the thermal imager can collect the temperature field data of the rotary kiln regularly (such as every 5~10 seconds), which can cover all areas of the rotary kiln.

In addition, the infrared thermal imager is installed near the rotary kiln, which has to withstand the test of wind, rain, snow and other adverse weather, as well as high temperature and dust. Therefore, the protective shell of the infrared thermal imager must have the ability to prevent dust and rain. When the ambient temperature is high, it must be able to cool the thermal imager to ensure the reliability of work. Additional lens protection components, detector protection components and dust protection devices are provided.

Scheme 1 is difficult to install on site, which requires a new slide rail. In addition, the railcar runs for a long time, and its service life is limited, so it needs regular maintenance. In addition, the stability of the slide rail will also affect the accuracy of the rotary kiln infrared monitoring system; Scheme 2 can use the existing supports around the rotary kiln for fixed installation, which is convenient and reliable for construction and installation. The communication control technology between the rotary kiln and the pan tilt is also relatively mature, so we recommend scheme 2.

Technical means and function realization

1. Infrared focal plane imaging technology

The infrared thermal imager adopts an advanced uncooled focal plane detector with 384 pixels × 288. Each time the thermal imager images the target, there are 110592 sampling points. Therefore, the thermal imager can form a plane image of the temperature characteristics of the whole rotary kiln surface. The detector has high sensitivity and temperature resolution of 0.12 ℃. Small temperature changes on the surface of the rotary kiln can also be reflected. In addition, with focal plane imaging, there is no distortion in the thermal image, and the proportion of the thermal image is completely consistent with that of the rotary kiln entity. The corresponding points on the rotary kiln body can be found directly according to the temperature abnormal points on the thermal image, which is convenient for the location of damage points.

1.1 Infrared real-time temperature measurement technology

Infrared thermography uses computer computing technology to calculate the temperature data of the object surface according to the original infrared data. And store the temperature data for statistical analysis.

2. Rotary kiln surface temperature analysis function

2.1 Statistics of surface temperature data of rotary kiln

Combined with the experience of Baosteel's ladle monitoring project, the following functions are set for the rotary kiln monitoring system: according to the statistical temperature field data, the maximum temperature trend analysis chart is established according to the zoning of the rotary kiln, and the alarm value threshold of different areas on the surface of the rotary kiln is established in combination with the maintenance experience. Through the pre alarm analysis, the service life of the rotary kiln is prolonged and the refractory is saved on the premise of safe use of the rotary kiln; Judge the cinder blockage fault according to the average temperature, and find the cinder blockage fault in time.

2.2 Rotary kiln lining damage alarm

The following figure shows the maximum temperature history curve of multiple surface temperature field data collection in a rotary block. Set a reasonable alarm value according to the statistical ladle surface temperature field data and empirical value. When the maximum temperature of the ladle surface reaches the alarm value, remind the staff to arrange maintenance work in real time, so that the rotary kiln can prolong its service life on the premise of ensuring safe production, so as to reduce production costs. The infrared imaging system itself adopts focal plane imaging technology. When a fault is found, the actual position of the fault point can be calculated according to the infrared picture of the alarm point.

2.3 Rotary kiln cinder blockage alarm

After long-term operation of the rotary kiln, there may be cinders attached to the inner wall in some areas, which may cause cinder blockage if not cleaned in time. The surface temperature of this area is different from that of other areas due to the different heat-resistant layer. Using this feature, we have measured the surface temperature of each block of the rotary kiln for many times during the trial operation, and recorded and counted the average temperature and maximum temperature of these temperature data. The average temperature alarm threshold of cinder blockage can be inferred from the statistics of this historical curve and experience. Then, the surface temperature of the rotary kiln is measured in real time and compared with the average temperature alarm threshold of cinder blockage, and then the cinder blockage fault in the rotary kiln can be judged.

3. Feasibility of rotary kiln infrared thermal image detection system scheme

Wuhan huajingkang Photoelectric Technology Co., Ltd. is a high-tech company specializing in providing infrared thermal imager products and industrial application solutions. At present, the company's infrared thermal imager product series mainly covers the fields of power system, iron and steel metallurgy, security monitoring and so on. Because the company's products have the characteristics of online real-time monitoring, high temperature measurement accuracy, customized customer application functions, etc., we successfully won the bid for the power monitoring system of a substation of the State Grid. In this system, we successfully used the PTZ control system, thermal imager imaging and accurate temperature measurement.

In the application of iron and steel metallurgy, our ladle infrared thermal image detection system has been successfully applied to an ironmaking plant of Baosteel. In this system, we have accumulated the infrared thermographic data of the ladle and improved the temperature measurement accuracy of high temperature metallurgy. In this system, we customized and developed rich functions for specific applications in the metallurgical industry, which is convenient for operators to use. The rotary kiln infrared thermal image detection system will integrate the user interface functions of the pan tilt control system, the thermal imager imaging system and the ladle infrared thermal image detection system in the substation power monitoring system. The main system components have been successfully applied and experienced by customers, so the scheme has high feasibility.

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