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ROTAB Series - ASTM D4058 Application note

 
The ASTM procedure
The ASTM standard method ASTM D4058 has been designed for catalysts, but can be conveniently applied, as it is highly consolidated and very precise (about +/- 1%), to other solid materials, preferably within the 0.85-20 mm size range.
The standard amount of material to be tested is 100 g, but reliable results can be obtained with smaller samples. The standard rotation rate is 60 +/- 5 rpm, but it has a small influence on the abrasion data, except for magnetic materials.
The total number of revolutions is 1800. The percentage of fines formed after such revolutions, sieved below 0.85 mm, gives the measurement of the material’s abrasion resistance.
The official text of the method can be found at www.astm.org
 
Catalyst pretreatment
The catalyst sample may require desiccation before testing.
Some practical examples are:
a)     Fines formation during catalyst loading in the reactor.
The catalyst should not be dried.
b)     Fines formation during reactor operation.
When the catalyst is activated in the reactor, the abrasion test has to be conducted on the activated sample.
When the catalyst is not activated, it should be dried at approximately reaction temperature.
 
Problems arising from low abrasion resistance of catalysts
a)     Environmental problems during reactor loading.
b)     Pressure drop increase in axial reactors.
c)     Bypass formation in radial reactors.
d)     Product contamination, in particular when solid.
 
Abrasion resistance specifications for some industrial catalysts
Abrasion resistance must be measured for any catalyst used in fixed-bed and trickle-bed reactors. For such catalysts, a maximum value of fines formed in the ASTM D4058 test is usually specified. Catalyst users should check this value for each batch of catalyst they purchase. The usual specifications of abrasion resistance for several industrial catalysts are reported hereunder.

 

PTA                               
Ammonia (prereduced)  
Hydrotreating                
Formaldehyde                
Methanol                        
Styrene                         
LTS                                
HTS                                  
1.5% max
2.0% max
2.0% max
3.0% max
3.0% max
3.0% max
5.0% max
8.0% max 


Ma.Tec. specialists are available to discuss any problem related to abrasion resistance.    


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