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Combustion furnaces and boilers play an important role in heating systems in many industries and commercial and administrative buildings. They can be used to heat products in the petroleum, chemical and pharmaceutical industries, and to produce or process molten products in glass, steel and other industries.
In most cases, because the combustion furnace and boiler have high working temperature and some faults can cause personal injury and death, they should be listed in the scope of predictive maintenance (PDM) plan to monitor their operating conditions.
The purpose of predictive maintenance plan (PDM) is to detect impending faults and deal with them before they occur, so as to avoid the shutdown of key equipment. A very important tool for monitoring the condition of combustion furnaces and boilers is the thermal imager, which can capture the two-dimensional image of the temperature curve of the measured object. Thermal images can reveal potential failure points in combustion furnaces and boilers and help extend the life of their fire-resistant insulation.
The following will focus on the use of thermal imaging technology to troubleshoot combustion furnaces and boilers, especially the inspection of the fire-resistant isolation layer inside the outer wall of the equipment or the isolation lining of the container used to process and transport molten materials.
Check what?
Use the thermal imager to check the key combustion furnace, process heater or boiler, and prioritize the equipment according to the severity of the failure threatening human health or safety, property, production efficiency or the product itself.
Highly skilled thermal imaging personnel will successfully report some high temperature points that indicate potential faults through the inspection of combustion furnaces and boilers. Obviously, cracks on pipelines transporting hot water, steam or high-temperature products may bring disastrous consequences, but those who try to use thermal imaging technology for such monitoring must realize that this is a very difficult and dangerous work, which puts thermal imagers and thermal imagers themselves at risk. Moreover, it also requires a lot of knowledge, training and experience to complete this work in order to achieve reliable results in harsh environments such as combustion furnaces or boiler interiors.
In comparison, as long as there is no shiny surface on the equipment, the external thermal imaging inspection of the combustion furnace and boiler is relatively safe and easy, and can help judge whether the equipment is normal.
What are you looking for?
In order to ensure the safety of personnel and property, combustion furnaces, boilers, process heaters and other heat generating equipment are equipped with isolation layers or refractory linings in their outer walls. Using a thermal imager, technicians can find high-temperature points on the outer wall. The high temperature point indicates the failure position of the refractory layer. Its goal is to maximize the service life of refractory materials and plan maintenance before the burn through of the outer wall of the equipment leads to fire, injury or worse. Of course, another problem caused by ineffective isolation or refractory layer is energy loss, which increases operating costs and reduces process efficiency due to heat loss.
A good inspection method for combustion furnaces and boilers is to formulate some regular inspection routes, including all key combustion furnaces, boilers, process heaters and other heat generating equipment. It is a good method to determine the frequency of inspection based on the nature and function of the equipment. For example, you may need to check important equipment running in harsh environments on a quarterly basis, while for those running in less harsh environments, you can check them on an annual basis.
What situation means "red alarm"?
Equipment with safety hazards should always have the highest maintenance priority. Obviously, one of the most likely dangerous situations is the failure of the combustion furnace or the steel ladle used to hold molten materials such as glass or molten steel.
There are two purposes for monitoring such devices:
1) Maximize the service life of the refractory layer of the equipment;
2) Prevent hot molten materials from splashing into the environment of production facilities.
What is the potential cost of the failure?
Catastrophic failures in the glass and steel industries, even if they do not cause personal injury or death, will bring millions of dollars in production losses. The cooled glass can no longer be reheated.
How can we recycle iron or steel that was once molten and has now hardened?
The following is a representative hourly shutdown cost in the industry where boilers, combustion furnaces and process heaters constitute key equipment for production: US $1million for pharmaceutical; US $800000 for food and beverage; 700000 US dollars for chemical industry; Metalworking $550000.
These figures are related to it performance losses, but expressed in terms of total downtime costs.
Subsequent actions
When using the thermal imager to find problems, please use the attached software to record the results in a report, including a thermal image and a digital image of the device. This is the best way to report the problems you found and make maintenance suggestions.
Imaging tips
Comprehensive comparison or qualitative analysis of refractory materials can bring objective cost savings. Comparing the detailed infrared inspection of the new steel ladle and the relined refractory wall with the similar infrared inspection of the similar steel ladle fire combustion furnace wall before relining can help establish the performance benchmark. These benchmark data will become the standard used to determine the acceptance criteria of new equipment, and can guide users to determine the time of the next lining.
Generally speaking, if it seems that a catastrophic failure is about to occur, the equipment must be stopped or repaired during its operation.
In the iron and steel industry, these two strategies are adopted at the same time. For steel spoons containing molten products, steel mills generally have enough steel spoons to stop using the faulty steel spoons and replace them with a good one. However, the refractory materials in some combustion furnaces and heaters in the iron and steel industry can be repaired by pumping a mortar to the weak or damaged refractory layer area (identified by a thermal image) during operation.
In each case, the maintenance effect and the maintenance materials used can be evaluated by the new thermal images obtained after the maintenance. With this information, you can continuously improve the predictive maintenance (PDM) plan for the refractory layer of combustion furnace and boiler.
