Venturi Scrubber Collection & Pressure Drop Calculator
Model high-energy particulate Venturi scrubbers: Calvert cut-power collection efficiency, throat velocity, Nukiyama-Tanasawa droplet atomization, aerodynamic pressure drop, and ID fan power.
1. Flue Gas Stream & Dust Properties
2. Venturi Geometry & Scrubbing Liquid
Scrubber Diagnostics & Cut Performance
Hydraulic & Impaction Numbers
5 Fatal Engineering Traps in High-Energy Venturi Scrubbers
1. The Sub-0.5 µm Energy Trap: Exponential Fan Power Explosion
Inertial impaction scales with particle mass (dp³). Attempting to capture sub-0.5 µm metallurgical fumes or carbon black with a low-energy scrubber (ΔP < 5 kPa) yields near-zero collection efficiency. Reaching 99% capture on 0.2 µm particles requires extreme throat velocities (>100 m/s) and pressure drops exceeding 16–22 kPa (65–90 in. w.g.), causing booster fan electricity bills to bankrupt plant operating budgets.
2. The Wet-Dry Transition Line Collar Crust & Throat Choking
At the converging inlet where hot unsaturated gas first strikes liquid spray, water evaporates instantly. Suspended minerals bake into an rock-hard ceramic collar on the steel lip. The collar chokes throat area, escalating gas velocity, throwing the ID booster fan into aerodynamic stall, and inducing severe casing duct vibrations.
3. Excessive Throat Velocity (>115 m/s) & Mist Re-entrainment
Operators frequently push throat velocity above 115 m/s seeking better collection. However, extreme aerodynamic shear shatters water droplets below 10 µm. These ultra-fine droplets have near-zero terminal settling velocity and blow right through downstream cyclonic mist separators, creating severe droplet carryover, fan wheel erosion, and acidic stack rainout.
4. Spray Nozzle Abrasive Wear & Dry Gas Channelling Voids
Recirculating abrasive scrubbing slurry rapidly erodes spray nozzles, distorting the spray pattern and opening gaps in the liquid curtain. Unscrubbed dusty gas streams bypass directly through these dry voids without contacting a single droplet, dropping plant collection efficiency from 98% down to 60% with zero change in measured pressure drop.
5. Slurry Suspended Solids Over-Concentration (>15% wt)
Restricting fresh water makeup allows recycled scrubber liquid to accumulate high suspended solids. Above 12%–15% solids by weight, slurry viscosity spikes, suppressing droplet atomization in the throat and plugging injection headers with compacted grit.
Governing Atomization & Calvert Collection Equations
The Nukiyama & Tanasawa Sauter mean droplet diameter (dd in μm):
dd = [ 585 / vthroat ] · √[ σL / ρL ] + 597 · [ μL / √(σL · ρL) ]0.45 · [ 1000 · (L/G) ]1.5
Inertial impaction parameter (Stokes number Kp):
Kp = [ Cc · ρp · dp² · vthroat ] / [ 9 · μgas · (dd × 10⁻⁶) ]
Hesketh / Yung-Calvert empirical throat pressure drop (ΔP in kPa):
ΔP = 1.03 × 10⁻³ · vthroat² · ρgas · (L/G)0.78 (kPa)
Overall collection efficiency for target particle size dp:
η = [ 1 - exp(-0.55 · (L/G) · √Kp) ] × 100%