A top-spray fluid bed granulator suspends the powder bed in upward-flowing hot air (40–90°C, 0.5–2.5 m/s) while spraying binder solution downward from nozzles above the bed — simultaneously granulating and drying in a single bowl. Processing 1–500 kg batches with inlet air volumes of 50–28,000 m³/h, it achieves granule size of 0.1–1.5 mm and residual LOD below 2% — the standard one-step granulation and drying configuration for pharmaceutical solid dosage manufacture under GMP.
Challenges
Spray Nozzle Clogging from High-Viscosity Binder
High-viscosity binder dries at nozzle tip between pulses — progressive orifice blockage.
Over-Wetting When Spray Rate Exceeds Evaporative Capacity
Excess spray creates saturation above evaporation rate — large lumps collapse fluidisation.
Channelling from Non-Uniform Air Distribution
Uneven distributor plate creates air channels — unmixed dry powder regions persist.
Electrostatic Powder Adhesion to Bowl Wall and Filter Bags
Fine cohesive powders adhere to surfaces — product loss and filter blinding.
Spray Coverage Non-Uniformity at Scale-Up
Single nozzle at lab; production bowl requires multiple nozzles for even coverage.
Solutions
- Self-Cleaning Anti-Drip Two-Fluid Nozzle with Purge Air: Continuous purge air prevents binder drying at nozzle tip — sustained spray pattern.
- Inlet Air VFD Control (0.5–2.5 m/s Real-Time Adjustment): Matched fluidisation velocity prevents over-wetting throughout binder addition.
- Multi-Zone Perforated Distributor Plate (Pressure Drop ±5%): Uniform air distribution eliminates channelling across full bowl cross-section.
- Full Earthing + Conductive SS Bowl Liner: Vessel earthing dissipates electrostatic charge — powder adhesion minimised.
- Multiple Spray Nozzles (Area = Bowl ز×π/4 ÷ 0.07 m² per Nozzle): Nozzle number scaled to maintain constant spray coverage density per unit bed area.
Applications
- Pharmaceutical: One-step wet granulation and drying for tablet and capsule manufacture under GMP.
- Nutraceuticals: Supplement powder granulation, vitamin blend agglomeration, probiotic granule production.
- Food & Beverage: Instant food powder granulation, coffee creamer agglomeration, flavour carrier granule.
- Chemical: Detergent granulation, catalyst support granule, specialty chemical particle agglomeration.
- Cosmetics: Pressed powder granule preparation, mineral makeup agglomeration for compact base.
Models & Capacities
2A. Top-Spray FBG — Models & Capacities (Indicative values; performance depends on product properties and process parameters. * At jacket surface temperature 60°C) | |||||||||||
Model | Net Vol. [L] | Batch Size [kg] | Inlet Air [m³/h] | Inlet Temp [°C] | Max Spray Rate [g/min] | Granule D90 [mm] | LOD [%] | Bowl Ø [mm] | Bowl H [mm] | Overall H [mm] | Connected Load [kW] |
FBG-TS-001 | 1.5 | 1 | 50–200 | 30–90 | 5–30 | 0.1–1.5 | <2 | 300 | 350 | 2,200 | 5 |
FBG-TS-003 | 5 | 3 | 100–400 | 30–90 | 10–60 | 0.1–1.5 | <2 | 400 | 450 | 2,400 | 8 |
FBG-TS-010 | 15 | 10 | 300–900 | 30–90 | 30–120 | 0.1–1.5 | <2 | 550 | 600 | 2,700 | 15 |
FBG-TS-030 | 45 | 30 | 800–2,500 | 40–90 | 100–400 | 0.1–1.5 | <2 | 750 | 780 | 3,200 | 30 |
FBG-TS-060 | 90 | 60 | 1,500–4,500 | 40–90 | 200–800 | 0.1–1.5 | <2 | 1,000 | 950 | 3,800 | 50 |
FBG-TS-120 | 180 | 120 | 3,000–8,000 | 40–90 | 400–1,200 | 0.1–1.5 | <2 | 1,200 | 1,150 | 4,400 | 75 |
FBG-TS-200 | 300 | 200 | 5,000–14,000 | 40–90 | 600–2,000 | 0.1–1.5 | <2 | 1,500 | 1,380 | 5,200 | 110 |
FBG-TS-300 | 450 | 300 | 7,000–20,000 | 40–90 | 800–3,000 | 0.1–1.5 | <2 | 1,800 | 1,600 | 6,000 | 150 |
FBG-TS-500 | 750 | 500 | 10,000–28,000 | 40–90 | 1,000–4,500 | 0.1–1.5 | <2 | 2,200 | 1,900 | 7,000 | 210 |
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