TFF

Free Online TFF & Ultrafiltration Processing Planner

Downstream Processing: Sizing tangential flow filtration (TFF), transmembrane pressure ($TMP$), permeate flux, concentration factor ($VCF$), and diafiltration ($DV$) buffer exchange.

DOWNSTREAM DSP • MEMBRANE TFF
MEMBRANE & HYDRODYNAMICS SETUP
Target Downstream Workflow
Feed Pressure P_feed (psi) 25.0 psi
Retentate Pressure P_ret (psi) 15.0 psi
Membrane Area A_mem (m²) 0.50 m²
Average Flux J (LMH / L/m²/h) 45.0 LMH
Initial Batch Volume V₀ (L) 50.0 L
Final Retentate Target V_ret (L) 5.0 L
TFF CASSETTE SKID & VOLUME TRAJECTORY
Cassette Skid: TMP = 20.0 psi, Permeate Qp = 22.5 L/h MWCO: 30 kDa Regenerated Cellulose
DOWNSTREAM HANDOFF ➔ STERILITY / FILL
Formulated concentrated retentate V_final = 5.0 L at 100.0 g/L ready to feed into Sterilization & Lethality (F₀) Analyzer for final thermal assurance.
TFF OPERATIONAL METRICS DSP METRICS
Permeate Generation Rate (Q_p)
22.5 L/h (375 mL/min)
Flux × Membrane Area
Feed Channel Pressure Drop (ΔP)
10.0 psi (0.69 bar)
P_feed - P_ret crossflow driving force
Impurity Clearance Efficiency
99.33% Removed
Buffer / small molecule exchange ($1 - e^{-DV}$)
Final Product Concentration
100.0 g/L
Starting from 10.0 g/L (10.0× VCF)
Membrane Sizing Load Ratio
100 L / m²
Recommended pilot range: 50–150 L/m²
📊 Computed Results & Analytical Outputs LIVE CALCULATION
Transmembrane Press. (TMP)
20.0 psi
1.38 bar average pressure
Concentration Factor (VCF)
10.0×
50.0 L ➔ 5.0 L retentate
Total Processing Time
3.11 h
2.00 h UF + 1.11 h DF
Diafiltration Buffer Required
25.0 L
99.33% Buffer exchange (5.0 DV)

📚 Tangential Flow Filtration (TFF) & Ultrafiltration/Diafiltration Guide Downstream DSP • Step 2 of 3

Theoretical Principles & Engineering Fundamentals

Tangential Flow Filtration (TFF)—also known as cross-flow membrane filtration—is used for biomass clarification, viral filtration, buffer exchange (diafiltration), and target molecule concentration (ultrafiltration). Sweeping feed solution across the membrane surface minimizes gel polarization and foulant cake buildup compared to dead-end filtration.

Governing Equations & Mathematical Formulations

Transmembrane Pressure (TMP) \text{TMP} = \frac{P_{\text{feed}} + P_{\text{retentate}}}{2} - P_{\text{permeate}}
Average pressure differential driving solvent permeation through the membrane barrier.
Volumetric Concentration Factor (VCF) \text{VCF} = \frac{V_{\text{initial}}}{V_{\text{final}}}
Degree of fluid volume reduction achieved during the concentration phase.
Permeate Flux J = \frac{\Delta V_{\text{permeate}}}{A_{\text{membrane}} \times \Delta t}
Filtration rate per unit membrane area, typically measured in LMH ($ ext{L}/(\text{m}^2 \cdot \text{hr})$).
Diafiltration Buffer Exchange C_{\text{imp,final}} = C_{\text{imp,initial}} \times e^{-N_D \times (1 - R_{\text{imp}})}
Washout of permeable salts/impurities where $N_D$ is the number of diafiltration volumes (DVs).

Industrial Benchmark Data & Parameter Reference

Process StageTarget MetricTypical Flux (LMH)Membrane MWCO
Harvest ClarificationCell / debris removal50 – 120 LMH0.22 μm / 0.45 μm Microfiltration
Ultrafiltration (UF)Concentration (VCF 5x–20x)25 – 60 LMH10 kDa – 30 kDa Pellicon/Cassette
Diafiltration (DF)Buffer exchange (5–8 DVs)30 – 70 LMH10 kDa – 30 kDa Ultrafiltration
Final FormulationHigh-concentration mAb10 – 30 LMH30 kDa Biomax / Centramate

Frequently Asked Questions (Bioprocess Engineering FAQ)

What Molecular Weight Cut-Off (MWCO) should I choose?
The standard bioprocess rule of thumb is to select a membrane with an MWCO that is 3 to 5 times smaller than the molecular weight of the target protein to ensure $>99\%$ retention.
How many diafiltration volumes (DVs) are required for complete buffer exchange?
Assuming zero retention of the permeable buffer salt ($R = 0$), 5 diafiltration volumes achieve 99.3% buffer exchange, and 7 DVs achieve 99.9% exchange ($e^{-7} = 0.0009$).
What is the difference between hollow fiber and flat sheet cassette TFF?
Hollow fibers provide open, low-shear tubular flow channels ideal for high-viscosity or shear-sensitive cell suspensions. Flat sheet cassettes provide higher packing density and mass transfer coefficients for clarified protein concentration.

BioFlo Bioprocess Engineering Network

This calculator is maintained by the simulation engineers at BioFlo Bioprocess Engineering. We specialize in industrial bioreactor design, computational fluid dynamics (CFD) modeling, oxygen mass transfer optimization, and custom digital twin development for pharmaceutical fermentation plants.

🌐 BioFlo Corporate & CFD Simulation 🔬 Full Bioprocess Workbench (14 Free Tools) ◂ Previous: Preparative Chromatography Sizer Next: Autoclave F0 Sterilization ▸ 🏭 Bioreactor Scale-Up 💨 kLa Mass Transfer 🧱 TFF Ultrafiltration