Comparison of conveying modes
Dilute Phase Conveying
| High gas velocities: | v = 25-40 m/s v = 5.000-8.000ft/min |
| Low product to air ratio: | range 1-5 to 1 |
| Low to medium pressure drop: | p = 0.1-1.0 bar p = 1.5 - 15 psig |
| Special pipe support requirements: | No |
Dilute phase characteristics:
- High dust volume
- Mostly coarse dust long and short streamers, depending on the product
- Dust surges at the end of the unloading process
- Low investment costs
- Difficult dust removal because of high dust volume and streamers
- High product losses in form of dust
Typical conveying layouts for polyolefine plants
Dilute Phase Conveying – Traditional layout with elutriators for dust separation
These systems can be upgraded easily with mobile or stationary DeDusters® located under the silos.
Dense Phase Conveying
| Low gas velocities: | v = 2-10 m/s v = 400-2.000ft/min |
| High product to air ratio: | range 15-50 to 1 |
| High pressure drop: | p = 0.5-3.5 bar p = 7 - 50 psig |
| Special pipe support requirements: | Yes |
Dense phase characteristics:
- Low dust volume
- Very fine dust, but high electrostatic charged dust, sticks to the pellet surface
- No streamers through conveying
- Streamer formation caused by purging
- High investment costs
- Very difficult to remove the electrostatically charged micro dust
- Low product losses in form of dust
Typical conveying layouts for polyolefine plants
Dense Phase system without dust separation
These systems can be upgraded easily with mobile or stationary DeDusters® located under the silos.
STRANDPHASE® Conveying
| Optimized gas velocities: | v = 15-25 m/s v = 3.000-5.000ft/min |
| Medium product to air ratio: | range 5-18 to 1 |
| Medium to high pressure drop: | p = 0.5-2.0 bar p = 7 - 50 psig |
| Special pipe support requirements: | No |
STRANDPHASE® characteristics:
- Low to Moderate dust volume
- Mostly coarse dust and some short streamers, depending on the product
- Low to moderate investment costs
- Easy dust removal with DeDuster®
- Low to moderate product losses in form of dust
Typical conveying layouts for polyolefine plants
Strandphase Conveying with Pellbows and dedusting under the silos
For new installations, Pelletron recommends the pellcon3® system, utilizing STRANDPHASE® conveying, Pellbows® and DeDusters®.
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