Efficient furnace linings are the key to reducing overall maintenance costs and ensuring facilities run smoothly without undue revenue loss due to downtime. Follow the five tips below to keep your furnace lining running efficiently:
• Tip 1: Evaluate the furnace liner by using infrared thermography inspection. Infrared (IR) thermography scans are an essential step for evaluating the quality of the furnace lining. Lining quality is critical to protecting the steel from heat and limiting heat loss and promoting overall furnace efficiency. Typically, the scan involves pointing an IR camera at several points on the furnace casing to analyze the outside temperature and identify hot spots where the unit is leaking heat or experiencing design issues that may not be visible from the outside. This is a particular issue with a painted surface.
• Tip 2: Use on-line maintenance repair. Depending upon the temperature, the difficulty of getting to a particular area or how big the hot spot is, conduct on-line repairs wherever possible. Most maintenance managers prefer the on-line repair option because it is reliable, fast and economical. This avoids revenue loss from the unit in question, as well as the consequential losses from shutting down additional connected units.
For example, where IR scans indicate on-line repairs are recommended, Morgan Advanced Materials pumpable Superwool® or Kaowool® can be pumped from the outside of the furnace or boiler, filling cracks and voids caused by deteriorated insulation. These products are ideal for providing improved thermal insulation efficiencies behind boiler tubes in sidewalls, seals and floors as well as repairs of ovens, furnaces and process equipment.
• Tip 3: Choose the right material for furnace rebuilds. When IR scans indicate the area of concern is too large for on-line repairs, the unit must be shut down for a furnace or process heater reline. Material selection is key to a successful furnace rebuild that will improve efficiency, reliability and lower maintenance costs. Material properties, including hardness, density, mechanical resistance or insulating factor, may vary depending upon the furnace’s application. Selection of the proper material is frequently done by using a heat flow analysis software program in which temperature and use factors are inputted to obtain information on the best materials to be used.
Keep in mind many units have older style insulation; with so many new, more efficient insulation types now on the market, consider upgrading when you have to reline the furnace. For example, Morgan’s Superwool Plus fiber has up to 20-percent lower thermal conductivity than competitive insulations. As a result, Superwool Plus fiber is 17-percent more energy efficient than traditional refractory ceramic fiber (RCF) and any other alkaline earth silicate (AES) insulations.
• Tip 4: Carefully consider engineering design. After selecting the proper materials, be sure the engineering design is suitable. Engineering is extremely important to ensuring the furnace relining is as long lasting as possible. Make sure the materials have enough studs to hold them in place and have sufficient joints for expansion or shrinkage. For instance, if you install a brick lining without the proper expansion joints, the brick could actually grow and end up pushing the entire lining off the furnace wall.
• Tip 5: Proper installation is key to success. Be sure the installation of furnace lining material is done properly and those doing the job have the proper skills for the task. There are a wide variety of products available and each one has different installation requirements. For example, with concrete products, if the concrete is not mixed with the right amount of water at the proper temperature, the material will not develop, will be difficult to place and will not reach expected properties. The bottom line is if you don’t install it right, it is as bad as not having a good design and not making a good material choice.
For more information on furnace lining efficiencies, contact the Thermal Ceramics business of Morgan Advanced Materials at nasales@morganplc.com.
