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04003
Applications Analysis: Increasing the Carrying Capacity of a 6’ Diameter Molten Metal Ladle
Molten metal ladle
Proposition:
A metal manufacturer is currently looking to improve the capacity (without reducing the efficiency) of a series of 10 small ladles that it operates at one of its manufacturing facilities. Each ladle is 6’ (1.83m) in diameter at the mouth, has a 4’ diameter base, a height of 5’, and has an approximate carrying volume of 42 ft3 (1.18m3). Each ladle is used to continually transport molten metals at a temperature of 1650°F. The company also desires to ensure that the outside cold face temperature of the insulation lining is 200°F (maximum). The current insulation lining of each ladle contains 3.00” of a Super-Duty Firebrick, followed by 1.75” of a ceramic fiber based paper, and 4.00” of 2,000°F Insulating Castable. The ladles operate continuously, 24 hours/day, 365 days/year.
Primary Goals:
Due to increases in demand for process efficiencies with minimum capital expenditures, the company is looking to achieve the following goals by re-insulating the ladles:
• Increase the capacity of the ladles 10%, if possible, simply by changing the insulation lining rather than purchasing newer, larger ladles.
• A steady state cold face temperature no greater than 200°F on the outside (cold face) of the insulation lining for the ladles.
• A heat loss no greater than the current lining’s estimated steady state heat loss (249/Btu/ft2/hr).
Secondary Goals:
• Any possible decrease in the amount of heat lost through the composite lining which could translate to financial savings in energy cost over the course of a calendar year.
Proposal:
By simply replacing the 1.75” Ceramic Fiber Paper component of the lining with .75” of DynaGuard Ladle Liner 16# material, all desired goals can easily be met.
Thermal Analysis & Comparison:
Thermal Analysis and Comparison chart
Results:
• A decrease from 1.75” to .75” in the wall of the composite lining of the ladle due to the presence of DynaGuard Ladle Liner 16# would increase the carrying volume of the ladle from 42 ft3 to 46 ft3. This provides a 10% increase in the overall carrying capacity of the ladles.
• The cold face requirement of 200°F maximum is met by the DynaGuard Ladle Liner 16# material.
• The heat loss requirement of no greater than 249.71 Btu/Ft2/Hr is met by the DynaGuard Ladle Liner 16# material, and is actually an improvement over the composite with Ceramic Fiber Paper (247.05 Btu/Ft2/Hr vs. 249.71 Btu/Ft2/Hr), yielding a greater degree of heat containment in the ladle and a minimization of heat loss through the composite.
Financial Analysis & Comparison:
Given the differences in heat loss (Btu/Ft2/Hr) for the two insulation composites in the ladles, the following can be estimated for the amount of heat lost through the complete quantity of 10 ladles in $/year for each:
Financial Analysis and Comparison chart
Results
The composite containing DynaGuardM Ladle Liner 16# material saves $350.61/year in energy cost by minimizing heat loss over the composite that does not contain microporous materials.
Conclusion:
The DynaGuard Ladle Liner 16# material is the best material to accomplish all the primary and secondary objectives stated by the company. It utilizes the least amount of material for the greatest thermal management and financial gains, and performs at the given temperature levels more efficiently than the other materials proposed.
For more information about how ThermoDyne’s DynaGuardM Ladle Liner, Flexible Board or Panel materials may be of use in your particular application, please contact ThermoDyne’s team of Application Engineers at toll-free: 866.741.5458.
Assumptions:
- 1 KwHr = 3413 Btu
- $.065/KwHr = estimated average for energy costs. This figure may vary with facility location and amount of energy used.
• Calculations assume ambient air temperature to be = 80_F, with natural convection consistent with an indoor environment.
• Calculations assume steady-state.
- Calculations and information provided are for comparison purposes only, and are not intended for design specifications as individual scenarios for material use may vary.
- Photo used courtesy of Acetarc Engineering Company and R.W. Hale & Associates
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