Abrasion in solid materials occurs because of the rubbing of solid pieces against each other (or any mechanical component).
The rubbing occurs in vessel / pneumatic transportation, handling the material, or loading a reactor. Abrasion leads to the formation of finer dust and to the consequent loss of precious material or valuable features..
Therefore, abrasion resistance is a property of the utmost importance for industrial catalysts. It also provides meaningful information for other industrial products (pharmaceutical tablets, fertilizers, sugar and ceramics).
ROTAB is a rotating cylinder abrasimeter measuring the abrasion resistance of solid materials (granules, pellets, etc.). In the ROTAB-AS/S the rotation rate of the vessel can be set in the range 30-90 rpm.
The constant-rotation version of the instrument (ROTAB-AS) features a fixed rotation rate of 60 rpm. Both instruments were designed according to the ASTM standard method ASTM D4058, covering the particle size range 0.85-20 mm, and feature a removable drum for dry box opening.
Measurements can also be performed on larger size materials.
touch screen display
Both ROTAB-AS and ROTAB AS/S feature a touch-screen display to operate the instrument.
The removable drum is required when poisonous materials are tested. The drum can be easily loaded and discharged in a dry-box.
Safety lock System
The system prevents the safety cage from opening while the drum is rotating.
The ASTM standard method ASTM D4058 has been designed for catalysts, but can be conveniently applied, as it is highly consolidated and precise, 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 describing this method can be found at www.astm.org
The catalyst sample may require desiccation before testing.
Some practical examples are:
- Fines formation during catalyst loading in the reactor.
- The catalyst should not be dried.
- 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.
- Environmental problems during reactor loading.
- Pressure drop increase in axial reactors.
- Bypass formation in radial reactors.
- Product contamination, in particular when solid.
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 | 1.5% max
Ammonia (prereduced) | 2.0% max
Hydrotreating | 2.0% max
Formaldehyde | 3.0% max
Methanol | 3.0% max
Styrene | 3.0% max
LTS | 5.0% max
HTS | 8.0% max
MaTec specialists are available to help resolve any problems related to abrasion resistance.
Size (W x H x D)
550 x 850 x 600 mm
White and black
Revolution counter (automatic stop at preset number of revolutions)
up to 9999
Compliant with ASTM standard method ASTM D4058
(particle size range 0.85-20 mm)
Optional (supplied on request)
No.20 ASTM sieve with pan and cover
110V/60Hz version available on request