Improving efficiency, making equipment smaller or using the same equipment to produce more product is becoming more important for businesses everywhere. By improving the efficiency of the insulation in industrial heating equipment – from small lab furnaces to large aluminum holding furnaces – businesses can reduce the amount of fuel needed to run the equipment and the amount of toxins released from the equipment. One way to do this is to use microporous insulation for equipment running up to 1200°C (2192°F) or using a microporous liner behind refractory materials for equipment running at higher temperatures.
Fig. 1. Without microporous insulation – surface temperature: 163°F; heat loss: 181 BTU/SF-Hr
All About Microporous Insulation
The original microporous theory was developed in the 1940s. The microporous product was originally developed for the nuclear industry in the 1950s and was quickly applied in aerospace and military applications. The product was further developed and commercialized for industrial uses and became popular in the storage heater and ceramic cooktop industriesMicroporous insulation is based on nanostructured submicron synthetic amorphous silica (SAS) and other environmentally safe materials. Long “chains” of SAS particles help to keep solid heat conduction to a minimum. Spaces in the structure are smaller than the mean free path of an air molecule, eliminating most of the gaseous heat conduction. Mineral-oxide opacifiers effectively block infrared radiation.
Basically, microporous insulation is a collection of fine compacted powders and fibers. It is manufactured in boards, panels, flexible panels and preformed shapes. Microporous insulation is usually completely inorganic and non-combustible, though some manufacturers add organic content to improve the machineability of the product. While this improves handling and makes machining the product easier, it is important for the end customer to understand that the organics will burn out, leaving a less sturdy product than typically desired.
Microporous insulation is totally non-combustible, and some grades can withstand continuous exposure to temperatures as high as 1200°C (2192°F). Typical grades can withstand continuous exposure to temperatures as high as 1000°C (1832°F). Within its temperature limits, it is the most effective insulation. It is fireproof, flame retardant, the lightest and most compact solution available, completely inorganic and non-combustible, load bearing and environmentally friendly. Microporous is three to four times more efficient compared to conventional insulations and 10 times more efficient than refractory materials. It also has excellent load-bearing capabilities. Typical densities are 250-500 Kg/m3(15-30 Lbs/ft3), with compression resistance of 615 kPa (89 PSI) at 10% deflection.
Most businesses deciding to use a microporous solution are trying to achieve one of three goals.
1. Save energy
2. Save space (decrease footprint of equipment)
3. Improve capacity/safety
Examples follow illustrating how the end user could achieve these goals.
Fig. 2. With microporous insulation – surface temperature: 127°F; heat loss: 95 BTU/SF-Hr
Example 1: Save Energy
Typical Application – Furnace Industry- Heat-treating furnace (Fig. 1)
- Process temperature – 1650°F
- Goal – save energy
Fig. 3. Without microporous insulation – outside diameter: 169 inches; height: 50 feet
Example 2: Save Space (Decrease Footprint of Equipment)
Typical Application – General Industry- Hydrogen reformer (Fig. 3)
- Operating temperature – 1900°F
- Goal – reduce diameter and length
- Save on reformer tubes and shipping
Fig. 4. With microporous insulation – outside diameter: 160 inches; height: 49 feet
Fig. 5. Without microporous insulation – surface temperature: 648°F; diameter: 45.75 inches
Example 3: Improve Safety/Capacity
Typical Application – Burner (Fig. 5)- Process temperature – 2300°F
- Tubular design
- Reduce surface temperature for safety without changing size.
Fig. 6. With microporous insulation – surface temperature: 443°F; diameter: 45.75 inches
Benefits of Microporous Insulation
Microporous insulation has been around for many years, but its use in the furnace industry has only recently begun to grow. With ever-increasing energy costs, the drive is on for better efficiencies. New product forms and improved manufacturing methods have made microporous insulation a better option for furnace applications. Microporous insulations can be used in a variety of furnace applications to save energy, increase capacity, save space or a combination of the three (Fig. 7).By using microporous insulation alone or in combination with other materials, equipment manufacturers and owners can achieve their desired results, whether it be to save energy, save space or increase safety/capacity. With the ever-growing emphasis on “green” materials and improving our environment, microporous insulation also offers advantages for industrial heating equipment. Manufacturers of the material can provide more information on how to use this extremely efficient material to reduce greenhouse emissions by keeping the heat where it belongs.IH
Fig. 7. Illustration of Microtherm benefits vs. conventional insulation
Additional related information may be found by searching for these (and other) key words/terms via BNP Media SEARCH at www. industrialheating.com: microporous insulation, efficiency, refractory, heat loss