Catalyst Crush & Shear Strength Testing

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Alfa Chemistry Catalysts

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Regarding the question of whether the catalyst charge can be safely reused, the main consideration is whether the catalyst can withstand the operating conditions in the reactor after being reloaded. The physical decomposition of the catalyst particles can lead to the formation of dust, which will increase the pressure drop through the reactor and eventually result in the need to replace the catalyst. Therefore, it is necessary to measure the crush and shear strength of the catalyst.

Services

Alfa Chemistry Catalysts provides customers with systematic catalyst crush and shear strength testing. If necessary, conventional physical techniques such as scanning electron microscopy, X-ray diffraction, and surface area determination can also provide indicative information for the evaluation of the reusable performance of the catalyst. Welcome to discuss your specific needs with us.

• Single particle crush strength test

When testing the crush strength of single pellets, our equipment can be used for single pellets and/or extruded radial pellets. The pellet is placed on the anvil of the transducer, and a movable piston crushes the pellet. When the electronic device connected to the computer detects the peak when the particles are broken, the result will be displayed on the computer. The test results and calculation results will be provided to customers as part of the comprehensive analysis report.

Standard Test

ASTM D7084 —— Standard test method for determining the overall crush strength of catalysts and catalyst carriers

ASTM D6175 —— Standard test method for the radial crush strength of extruded catalysts and catalyst carrier particles

• Bulk crush strength test

When testing bulk crush strength, our equipment can determine the crush resistance of pellet beds with a maximum size of 6 mm.

Standard Test

ASTM D4179 —— Standard test method for single particle crushing strength of shaped catalyst shape

SMS-1471 —— Alternative body crushing strength of catalyst

• Bulk shear test

In silos and moving bed reactors, the catalyst support beads are not only subjected to normal crush stress, but also shear stress. In order to study the resistance of the catalyst particles in the failure zone where the shear strain is very high, a shear cell can be used for testing.

Application

According to the work of Ouwerkerk [1], the schematic diagram of the annular shear cell is shown in Figure 1. The sample remains in the annular space. The lower part of the battery is rotated on the central axis by the electric motor, and the upper part remains stationary and is loaded by the cylinder. The unit contains annular rings on the upper and lower surfaces to clamp the particles and avoid any slippage at the boundary. A sample of the catalyst beads can then be subjected to known stress, strain, and strain rate, and fracture can be quantified by gravimetric analysis.

Figure 1. Schematic diagram of the annular shear cell. [2]

References

1. C.E.D. Ouwerkerk. (1991). "A micro-mechanical connection between the single-particle strength and the bulk strength of random packings of spherical particles." Powder Technology 65(1-3): 125-138.
2. N. Brunard. (2000). "Methodology for Investigating the Mechanical Strength of Reforming Catalyst Beads." Oil & Gas Science and Technology – Rev. IFP 55(1): 67-85.