Effectiveness factor in biological external convection: study in high viscosity systems.

Area of Science:

• Biochemical Engineering
• Process Optimization
• Rheology

Background:

• Alginate and xanthan are crucial biopolymers with applications in various industries.
• Understanding mixing effects is vital for optimizing their synthesis.
• Previous studies often focused on low-viscosity systems, limiting broader applicability.

Purpose of the Study:

• To investigate the influence of mixing on alginate and xanthan synthesis efficiency.
• To analyze the effectiveness of the dimensionless reaction convection number (N(RC)) in correlating synthesis performance.
• To compare N(RC) with traditional diffusion models for high-viscosity systems.

Main Methods:

• Experimental analysis of alginate and xanthan synthesis under varying mixing conditions.
• Calculation of the reaction convection number (N(RC)) based on power input per unit volume.
• Comparison of effectiveness factors (eta) with N(RC) and biomass content.
• Correlation of N(RC) with process efficiency across a wide viscosity range.

Main Results:

• Decreased power input led to reduced growth and production rates.
• Effectiveness factor (eta) showed weak dependence on biomass content for both polymers.
• A strong correlation was established between effectiveness and N(RC) for tested models.
• N(RC) proved effective for viscosities ranging from 0.001 to over 1 kg m(-1) s(-1).

Conclusions:

• The reaction convection number (N(RC)) is a valuable parameter for assessing mixing efficiency in biopolymer synthesis.
• N(RC) offers a unified approach to correlate effectiveness, applicable to systems with significant external convection and internal diffusion limitations.
• This study highlights the utility of N(RC) for optimizing industrial-scale production of alginate and xanthan.