Technical Paper


PHYSICAL & CHEMICAL PROPERTIES A comparison of physical and chemical properties of Frimul FX and traditional mullite bonded corundum products is outlined in Table 1 below:-


Property Bulk Density, lb/ft3 (g/cc) Apparent Porosity, %


Cold Crushing Strength, psi (MPa)


Chemical Composition Al2


O3


SiO2 O


K2 Na2 O


Phase Composition Mullite


Corundum Thermal Properties


Thermal Expansion 68-2732°F/20-1500°C, %


Thermal Conductivity, Btu in/ft2


h°F @ hot face 1832°F 0.91 14.3 Table 1. DSF Frimul FX vs Typical 90’s SRU Lining Materials


In addition to creep resistance, other intrinsic physical and thermal attributes positively influence lining and therefore unit stability:-


• Density; ~14% lower cf traditional lining materials


• Thermal conductivity; ~21% lower (@1832°F) cf 90s traditional lining materials


• Thermal Expansion; ~21% lower (@2732°F) cf 90s traditional lining materials


The above properties mean a Frimul FX SRU lining weighs less than Ref


D4314 D4315 D4316


D4495A D4495D D4496


Standard


DIN EN 993-9 ASTM C832 ASTM C832 ASTM C832 DIN EN 993-9 ASTM C832


Sample


Cylinder Prism Prism Prism


Cylinder Cylinder


Load (PSI)


29 25 25 25 29 25


Table 3. Summary of Frimul FX Creep tests performed at 3000°F/1650°C


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Loading Orientation Pressing


Perpendicular Perpendicular Perpendicular Pressing Pressing


Expansion (%)


0.79 1.04 0.96 0.92 1.00 1.07


Creep (%) 50-100h 0


-0.09 -0.1


-0.04 -0.08 -0.17


Total


+0.02 -0.23 -0.19 -0.12 -0.22 -0.56


Before/ After


-0.19 -0.17 -0.08 -0.05 -0.17


1.15 18.0 DSF Frimul FX 164 (2.62) 16.2 16099(111)


75.6 24.2 0.08 0.20


96 1


90’s


190-199 (3.05-3.18)


16.0-16.8


11313-14504 (78-100)


90.0-96.0 3-9.28 0.01 0.17


7.0-16.6 80.6-87.0


Calculated hot face lining volume (m3


)


Traditional material weight (T) Frimul FX weight (T)


REFRACTORIES ENGINEER


THE


that constructed with traditional material, the backing thickness can be reduced without detrimental increase in shell temperature and overall heat loss is reduced. This maintains an appropriate shell temperature (350- 550°F) to avoid condensation of sulphuric acid at lower temperatures or sulfidation at higher temperatures. A potential decrease in backing lining thickness can increase the overall reactor capacity by 3.4% (see example for 12ft diameter reactor in Table 2 below).


3" backing 20.26


61.597 53.087


Table 2. Refractory lining volume and associated tonnage CREEP UNDER LOAD


The objective was that Frimul FX should exceed the creep resistance of present materials and meet the future auspices of relevant API standards, to qualify this it was specified that maximum deformation should be 0.5% at the end of a 100 hour hold ASTM C832 or DIN EN 993-9 creep under load at 3000°F/1650°C, 25psi.


Frimul FX has been through an extensive creep testing programme encompassing both ASTM and ISO/BSEN test methods. A summary of all tests performed at 3000°F/1650°C is shown in the following figures. There does seems to be an anomaly in the results when a cylinder specimen is tested; the deformation recorded during the test does not correlate closely to the before/after measurements which may be due to an idiosyncrasy with the measurement system.


Numerous tests have also been performed at 2900°F/1600°C; at this temperature virtually no creep is observed, the material is perceived as “zero” creep within the constraints of experimental error and the inherent stability of the creep apparatus.


MICROSTRUCTURE & SIO2 STABILITY


A SEM back scattered image of Frimul FX is shown in Figure 5, high firing temperature (3100°F) ensures extensive mullite intragranular and intergranular bonding (light grey); there is no free silica, the silicate (bright) that remains is encapsulated in the mullite matrix. The residual corundum (dark grey) is mainly intragranular which under high loading imparts a small expansion to stabilise the material.


4" backing 19.95


60.642 52.263


14


November 2019 Issue


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