An attrition risk assessment starts by defining what product damage means commercially. Once the acceptable change is measurable, tests can connect particle condition to the feeder, route and operating conditions that cause it.
An attrition risk assessment determines whether normal engineering experience is sufficient, a representative material trial is required or the route should be redesigned before a roots blower duty is finalized.
Define the Commercial Damage Criterion
“No degradation” is rarely a practical specification. The project should define what damage matters to the customer: increase in fines, loss of intact pellets, coating removal, shape change, dust generation, reduced dissolution performance or movement outside a saleable size range.
The measurement method and acceptance limit should be agreed before testing. Mean particle size alone is often inadequate because a small change in average can conceal a commercially important fine fraction. The full particle-size distribution or another product-specific measure provides a stronger baseline.
Rank the Material Sensitivity
Review particle structure, size distribution, density, hardness, porosity, coating, moisture and temperature. Agglomerates may fail at weak internal bonds, crystals may chip at edges, and warm polymer pellets may soften rather than fracture.
Previous handling history matters. Material recycled through a test loop may already have lost its weakest particles. A production sample taken before the proposed conveying step should therefore be compared with product collected after the complete route.
Rank the Route Severity
Create a route inventory covering feeder, initial acceleration, pipe length, internal bore, number and geometry of bends, vertical sections, diverters, flexible hose, separator and receiver entry. Count repeated handling cycles separately from distance.
Bends deserve attention because they change particle direction and create concentrated impact, but a high-velocity receiver entry or crushing feeder can dominate the result. The assessment should identify every severe momentum change rather than assigning all risk to the pipe.
Evaluate the Operating Window
Higher conveying-air velocity generally raises particle velocity and impact severity, but the relationship depends on drag, particle inertia and pressure expansion. A positive-pressure single-bore line can experience its highest gas velocity near the discharge.
The design objective is the lowest verified airflow that maintains stable transport throughout the route—not the lowest theoretical value and not the blower’s maximum volume. Reducing flow below the stable boundary can create sliding deposits, plugs or repeated restart impacts.
Dense-phase or low-velocity conveying may reduce impact for suitable materials, but it is not a universal remedy. Product can still experience compression, abrasion and particle-to-particle forces. Flow mode must be demonstrated for the actual grade and feeding method.
Select the Next Action
A low-risk case may proceed using established material data, a direct route and a reasonable velocity margin. A medium-risk case should receive targeted tests of critical bends, feeder or receiver entry. A high-risk case—valuable fragile product, multiple bends, uncertain material strength or strict fines limit—normally justifies representative pilot conveying.
Where testing is not possible, redesign options include simplifying the route, controlling downstream velocity, changing bend or receiver-entry geometry and reducing repeated transfers. The uncertainty should remain visible in the commercial offer.
Convert the Accepted Window into a Blower Duty
Once the material-performance region is established, define blower-inlet volume, normal and maximum differential pressure, speed-control range and operating profile. Check receiver filtration because generated fines can increase dust load and pressure over time.
Use the attrition assessment to define a testable product-quality limit before changing conveying conditions. Pair representative samples with route and operating data so the chosen design can be accepted on measured product condition.
Glossary
Attrition: Progressive loss of particle size, edges, surface or coating during handling.
Damage criterion: Measurable product-quality limit used to accept or reject conveying performance.
Friability: Tendency of a material to fracture or generate fines under mechanical handling or impact.
Handling history: Previous transfers, impacts and storage conditions that can change material strength or size distribution.
Route severity: Combined product-damage potential of acceleration, distance, bends, components and repeated cycles.
Surface loss: Removal of coating or outer particle material without complete fracture.
Whole-route assessment: Evaluation of feeder, pipeline, valves, separator and receiver as one damage system.