Benchtop Recirculating Tunnel Tray Dryer
Insulated drying duct with variable-speed blower and 3.0 kW electrical finned air heaters.
Chemical & Process Engineering / Convective Tray Drying Kinetics
FREE TO EXPLORELABORATORY 24 · CHEMICAL & PROCESS ENGINEERING
Convective Tray Drying Kinetics & Constant-to-Falling Drying Rate Transition
Determine drying rate curves for a wet porous granular slab in a convective hot-air tray dryer, evaluate the constant drying rate R_c as a function of air velocity v_a, and identify critical moisture content X_c. 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.
CONSTANT DRYING FLUX R_C—
PROCESS & PILOT PLANT TELEMETRY
Ready to sample with Air Velocity v_a = 3.0 m/s.
Adjust Air Velocity v_a, 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 (1.0 to 6.0 m/s). Evaluated using a 200 mm × 200 mm tray (active area A = 0.040 m^2, dry sand mass L_s = 1.20 kg, initial moisture X_0 = 0.25 kg/kg) in a 50.0 °C drying tunnel. Linear regression models constant drying rate R_c versus (v_a)^0.8 to extract S = 0.6500 kg/(m^2·h)/(m/s)^0.8.
Process apparatus & industrial sensors.
Continuous Under-Pan Digital Electronic Balance
Continuously records total tray mass in real-time with 0.01 g precision during drying.
Instrumented Drying Tray with Insulated Edges
200 mm × 200 mm × 15 mm stainless steel tray (area 0.040 m^2) insulated on sides and bottom.
Digital Hot-Wire Anemometer Probe
Measures parallel air sweep velocity v_a from 0.5 to 8.0 m/s with 0.05 m/s precision.
Digital Wet-and-Dry Bulb Psychrometer Array
Measures inlet and outlet air dry-bulb temperature (50.0 °C) and wet-bulb temperature (28.0 °C).
Moisture Analyzer & Convection Drying Oven
Oven dries final solids at 105 °C to establish absolute dry solid mass L_s = 1.200 kg.
FOLLOW THE METHOD
A reason behind every step.
Determine drying rate curves for a wet porous granular slab in a convective hot-air tray dryer, evaluate the constant drying rate R_c as a function of air velocity v_a, and identify critical moisture content X_c. Standardized parameter settings: 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 m/s.
01
Tunnel Warm-Up & Psychrometric Equilibrium
Set air heater to 50.0 °C and blower to moderate speed; circulate air for 20 minutes until dry-bulb (50.0 °C) and wet-bulb (28.0 °C) steady state is achieved.
02
Wet Slab Preparation & Placement
Mix 1.200 kg of dry quartz sand with 300 g of water (X_0 = 0.250 kg/kg); pack into the tray flush with the rim and place onto the balance cradle.
03
Initial Air Velocity Setpoint
Adjust blower speed to establish air velocity v_a = 1.0 m/s across the tray surface; record initial mass at t = 0.
04
Continuous Mass Loss Logging
Log tray mass every 60 seconds over 40 minutes; compute moisture content X(t) and instantaneous drying rate flux R = -(L_s/A) · (dX/dt).
05
Velocity Progression Protocol
Repeat tests with fresh identical wet slabs at air velocities v_a = 2.0, 3.0, 4.0, 5.0, and 6.0 m/s, recording the constant drying rate plateau R_c for each run.
06
Drying Rate Curve & Scaling Regression
Plot R versus X to locate critical moisture X_c, plot R_c versus (v_a)^0.8, and fit a linear regression through the origin to determine S.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into chemical process engineering insight.
Points are your recorded observations. The solid regression line validates Convective Tray Drying Kinetics mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
R_c = S · (v_a)^0.8 = 0.6500 · (v_a)^0.8
| # | Hot Air Drying Velocity v_a (m/s) | Constant Drying Flux R_c (kg/(m^2·h)) | Air velocity factor (v_a)^0.8 ((m/s)^0.8) | Constant drying rate flux R_c (kg/(m^2·h)) | Remove |
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CHECK YOUR UNDERSTANDING
Explain what the process engineering metrics mean.
During the constant-rate drying period of a wet solid, the surface temperature of the solid equals:
The transition point separating the constant-rate drying period from the falling-rate period is called:
Convective mass transfer over a flat tray surface dictates that the constant drying rate R_c scales with air velocity v_a as:
Moisture that cannot be removed by contact with air of given temperature and humidity is termed:
THEORY AND UNIT OPERATIONS CONTEXT
Process engineering background & physical principles.
Drying of moist solids is an energy-intensive simultaneous heat and mass transfer unit operation in chemical engineering, encompassing the manufacturing of pharmaceuticals, pigments, fertilizers, catalysts, polymers, and food products. In convective tray drying, hot dry air sweeps across exposed wet granular slabs placed in shallow trays. Heat conducts and convects from the air stream to the wet solid surface, providing the latent heat required to evaporate moisture, while evaporated water vapor diffuses across the hydrodynamic boundary layer into the bulk air. Plotting the drying rate flux R = - (L_s / A) · (dX / dt) against moisture content X (dry basis, kg water/kg dry solid) reveals characteristic drying periods. In the initial constant-rate drying period (X > X_c), the solid surface is completely saturated with free liquid water, and vaporization proceeds at a constant rate R_c governed purely by external boundary layer heat and mass transfer. Because convective mass transfer across a flat plate scales with air velocity as v_a^0.8 (Reynolds analogy), the constant drying rate follows: R_c = S · v_a^0.8. When moisture drops to the critical moisture content X_c, capillary action can no longer replenish surface water, dry spots appear, and drying enters the falling-rate period where internal moisture diffusion governs drying. In this laboratory investigation, a wet sand slab is dried in a benchtop tunnel tray dryer across air velocities from 1.0 to 6.0 m/s at 50.0 °C to determine the constant drying rate scaling slope S and identify critical moisture content X_c.
R_c = S · (v_a)^0.8 = 0.6500 · (v_a)^0.8
Evaluated using a 200 mm × 200 mm tray (active area A = 0.040 m^2, dry sand mass L_s = 1.20 kg, initial moisture X_0 = 0.25 kg/kg) in a 50.0 °C drying tunnel. Linear regression models constant drying rate R_c versus (v_a)^0.8 to extract S = 0.6500 kg/(m^2·h)/(m/s)^0.8.