Bulk crush testing of catalysts

A test method for bulk crush testing of catalysts and catalyst bases has been developed that significantly reduces interlaboratory data scatter. For excellent interlaboratory reproducibility, identical packing density of the catalyst in the cell and moisture content of the catalyst must be maintained. The new cell design improves the uniformity of the applied load across the top of the bed and thus reduces the potential of premature fines formation. 

The ASTM D-32 Committee on Catalysts has investigated the variables associated with bulk crush testing of formed catalyst and catalysts supports. The most critical parameters include packing density of the catalyst in the cell, the ratio of the height of the bed to the diameter of the bed, and moisture content of the catalyst. 

Bulk crush measures the ability of the catalyst to support the weight of the catalyst bed. This is difficult to measure precisely and has not yet been standardized. This test is now done on a proprietary basis. The paper by S. A. Bradley, et al.(6) addresses a procedure now under consideration for standardization which, if adopted, should be valuable to catalyst users and producers for specification and quality control. 

Hardness and attrition of particles and extrudates can be measured according to the ASTM hardness test or by measuring of the abrasion index. For activated carbons as catalyst carrier bulk and particle crushing strength tests have been developed. In Table 4 the hardness, the abrasion index and crushing strength are given. Extrudated carbons are extremely hard. 

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