Extending Centrifuge Dewatering into the Dryer Realm:
Washing & Drying in a Centrifuge using Hot Air/N2 or Steam
Pressure Added Centrifugation
PAC®
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Fcen
FP
6 bar
What is PAC?Pressure Added Centrifugation (PAC).
A unique system that enables the Heinkel Inverting Filter Centrifuge to dewater and then wash and dry products in the bowl of the centrifuge by introducing high-pressure air, N2 or steam into the sealed basket where solids are collected - while still under rotation. The only exit path for the air or steam is via the cake void spaces.
Pressure Added Centrifugation = PAC®
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FS
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FS
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∆pCapillary Forces
Centrifugal Forces
∆p ∆p
seal betweenfeed pipe androtating bowl
Nitrogen withup to 6 bar
rotational speedcan be reducedduring pressurestep!
PAC® also Improves Cake Consistency
Before PAC – Paste Like After Pac – Solid Product
► Difficult-to-filter products can be dewatered►Products will not stick to the Solids Housing► No cannon-balling in dryers
6 bar
PAC can also improve the cakeconsistency, e.g. thixotropiccakes, which may stick onthe Solids Housing.
Pressure-Added-Centrifugation(PAC) to pre-dry the filter cake. Will avoid problems coming From discharging a “wet” cake.
Product Drying with JETSTREAM®
PAC: N2 removes liquid mechanically out of cake capillaries
Jetstream: heated nitrogen removes solvent by evaporation
PAC: 6 bar N2
Atmospheric pressure
► PAC + Jetstream of HEINKEL enables to process and handlea wide range of very difficult and problematic products
Jetstream: N2 and temperature
.Test with standard centrifugation (no PAC !!) LOD > 55 % LOD
Wet and Sticky Products = Product Loss
Test with Pressure Added Centrifugation: LOD = 20%
Surface Moisture Removed = Higher Throughput and Profitability (minimal product loss)
Filling
Suspension
`
toFiltrate-receiver
Washing
Wash liquid
toFiltratereceiver
Spinning – Cake dewatering
ToFiltrate-receiver
Filling Washing Spinning Discharging
HypercentrifugationPressure Added Centrifugation PAC®
≤ 6 bar
To Filtrate
Receiver
Vent of BowlNitrogen
Real Pressure Added Centrifugationis only possible with theHEINKEL Inverting Basket!
Discharging of Filter CakeFilling Washing Spinning Discharging
Pressure Added CentrifugationPAC® — Examples
Product nameResidual moisture
centrifugationResidual moisture with PACHYPERCENTRIFUGATION®
Antiallergical Substance
Alkaloid
Food Additive
Metal Powder
Silicon Carbide
Vitamine
30 %
45 %
22 %
26 %
19 %
39 %
11 %
32 %
5 %
12 %
6 %
24 %
► PAC reduces significantly the residual moisture! ► Inverting Filter Centrifuges is the only type which
can operate with pressure centrifugation!
Fixed Bed Drying • Sealed Cake Design Ensures Even Flow Through Cake
• High Heat & Mass Transfers… Ensures Rapid Evaporation
• Overcomes Surface Tension & Reduces Viscosity of Moisture
• Temperatures of up to 125°C Pressures up to 6 bar g
• LOD’s: from 14% to 0.002% (in 16 minutes) water wet pharmaceutical from 22% to 3% (in 5 minutes) MIBK wet polymer from 11% to 0.08% (in 20 minutes) IPA wet pharmaceutical
HF Inverting Filter Centrifuge
The PAC Difference
API after Discharge without PAC
API after Discharge with 20 minutes of PAC at 100 deg. C