Transparent Vertical Fluidization Column
75 mm inner diameter acrylic column equipped with millimeter scale for bed height measurement.
Chemical & Process Engineering / Fluidized Bed Hydrodynamics
FREE TO EXPLORELABORATORY 04 · CHEMICAL & PROCESS ENGINEERING
Fluidized Bed Hydrodynamics & Minimum Fluidization Velocity via Ergun Equation
Investigate pressure drop across a granular bed of ballotini glass beads as a function of superficial gas velocity, determine the minimum fluidization velocity u_mf, and validate the Ergun equation in fixed and expanded bed regimes. Explore interactive transport phenomena, unit operations simulation, and chemical engineering telemetry.
TRANSPORT PHENOMENA · UNIT OPERATIONS · PROCESS CONTROL · REACTION ENGINEERING
Your virtual chemical and process engineering laboratory.
BED PRESSURE DROP ΔP—
PROCESS & PILOT PLANT TELEMETRY
Ready to sample with Velocity u_0 = 6.0 cm/s.
Adjust Velocity u_0, then execute chemical process trial.
Chemical and process engineering telemetry is evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity transport phenomena and unit operations modeling.
Process engineering assumptions and boundary condition limits
The transport and thermodynamic models apply within the specified calibrated operating window (2.0 to 12.0 cm/s). Evaluated using a 75.0 mm ID transparent column packed with spherical glass ballotini (mean diameter d_p = 250 μm, density ρ_s = 2500 kg/m^3) to a resting height L_0 = 300 mm. Linear regression quantifies the fixed-bed Darcy/Ergun regime up to u_mf.
Process apparatus & industrial sensors.
Porous Sintered Metal Gas Distributor Plate
Ensures uniform, non-channeling superficial gas distribution across column cross-section.
Calibrated Glass Ballotini Spherical Packing
Monodisperse spherical particles (d_p = 250 μm, density 2500 kg/m^3) providing reproducible bed voidage.
Oil-Filled Inclined Differential Manometer
Measures bed pressure drop ΔP with 0.01 kPa sensitivity across fixed and fluidizing states.
Rotameter Air Flow Metering System
Controls superficial air velocity u_0 from 0 to 20 cm/s via precision needle valve.
Cyclone Separator & Exhaust Air Filter
Captures any elutriated fines at high gas velocities to prevent particulate escape.
FOLLOW THE METHOD
A reason behind every step.
Investigate pressure drop across a granular bed of ballotini glass beads as a function of superficial gas velocity, determine the minimum fluidization velocity u_mf, and validate the Ergun equation in fixed and expanded bed regimes. Standardized parameter settings: 2.0, 4.0, 6.0, 8.0, 10.0, 12.0 cm/s.
01
Resting Bed Packing & Height Datum
Pour glass beads into the column, tap the cylinder gently to settle into reproducible dense packing (voidage ε ≈ 0.40), and record resting bed height L_0 = 300 mm.
02
Zero-Flow Pressure Verification
Isolate the manometer and verify zero differential reading across bed pressure taps before initiating airflow.
03
Low Velocity Air Introduction
Open the air supply valve to establish a superficial velocity u_0 = 2.0 cm/s; allow pressure to steady and record differential manometer reading ΔP.
04
Pre-Fluidization Velocity Stepping
Increment air velocity in steps of 2.0 cm/s through 4.0, 6.0, and 8.0 cm/s, observing fixed bed pressure drop and verifying absence of particle motion.
05
Minimum Fluidization Detection
Advance velocity past 8.5 cm/s; observe the onset of particle reorientation, bed unlocking, bubbling, and the plateau of differential pressure.
06
Linear Regression of Fixed Bed Regime
Plot bed pressure drop ΔP versus superficial velocity u_0 in the fixed bed regime to evaluate the hydraulic resistance slope S and calculate u_mf.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into chemical process engineering insight.
Points are your recorded observations. The solid regression line validates Fluidized Bed Hydrodynamics mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
ΔP = S · u_0 = 0.4250 · u_0
| # | Superficial Gas Velocity u_0 (cm/s) | Bed Pressure Drop ΔP (kPa) | Superficial gas velocity u_0 (cm/s) | Bed pressure drop ΔP (kPa) | Remove |
|---|
No readings yet. Execute a process trial and record it.
Calculate it yourself.
CHECK YOUR UNDERSTANDING
Explain what the process engineering metrics mean.
At the minimum fluidization velocity u_mf, the pressure drop across the bed equals:
In the Ergun equation, the term dominant at low Reynolds numbers (Re_p < 10) is proportional to:
Beyond the minimum fluidization velocity, as gas velocity increases further in a bubbling bed, the pressure drop:
According to the Geldart particle classification, 250 μm glass ballotini beads behave as:
THEORY AND UNIT OPERATIONS CONTEXT
Process engineering background & physical principles.
Fluidized bed reactors and contactors represent pivotal unit operations in catalytic cracking, combustion, gasification, drying, and polymer synthesis. When fluid flows upward through a stationary packed bed of solid particles, viscous and inertial drag forces generate a pressure drop ΔP that escalates with superficial fluid velocity u_0 in accordance with the semi-empirical Ergun equation. As fluid velocity increases, aerodynamic drag on individual particles eventually balances the buoyant gravitational weight of the bed. At this critical juncture, known as the incipient or minimum fluidization velocity u_mf, particles unlock from static contact, the bed unlocks into a fluid-like state, and pressure drop plateaus at a constant value equal to the net buoyant weight per unit cross-sectional area: ΔP_max = (1 - ε_mf) · (ρ_s - ρ_f) · g · L_mf. Further increments in gas velocity cause bed expansion, bubble formation, and vigorous solids mixing with virtually no additional increase in overall pressure drop. In this laboratory investigation, upward air flow through a vertical column packed with glass ballotini particles is monitored to measure the pre-fluidization resistance slope S, identify u_mf, and verify Ergun hydrodynamics.
ΔP = S · u_0 = 0.4250 · u_0
Evaluated using a 75.0 mm ID transparent column packed with spherical glass ballotini (mean diameter d_p = 250 μm, density ρ_s = 2500 kg/m^3) to a resting height L_0 = 300 mm. Linear regression quantifies the fixed-bed Darcy/Ergun regime up to u_mf.