Food Process Design I Winter Semester 2024/25

Food Process Design I (1503-420)

• Course offered by the Institute of Food Science and Biotechnology, Department of Process Engineering and Food Powders, University of Hohenheim.
• Course is for the Winter Semester 2024/25.
• Focuses on mass transfer as part of food processing.

Master Lectures in FPE

• Targets of the master training focus on an engineering approach for food technologists.
• Includes elements of tackling engineering problems effectively, understanding the reasoning behind assumptions made, identifying the scientific basis of topics, locating relevant information, and generating new knowledge (R&D as a job target).

FG LVT: Process Engineering and Food Powders

• Lectures cover transport phenomena in processing.
• Topics include: Transport Phenomena, Line design & Scale up, Process Product Interactions (Cereals & Sweets), Drying and Instantisation, and Encapsulation of Biofunctional Ingredients.
• Lecture types are (O)bjective, (E)ngaging

Expectations and Objectives

• Course expectations include what students want to achieve, specific questions they have, desired learning outcomes, and how the lecture fits into the broader context of the master program.

Optimal Process Design and Transport Phenomena

• Optimal design centers on relationships between the effect, effort, and efficiency as well as energy efficiency and investments.
• Optimal design considerations include quality and yield.
• Transport phenomena include all modes such as heat, mass and momentum transport.

Efficiency vs. Effectiveness

• Efficiency quantifies the result relative to the effort or resources invested.
• Efficiency varies based on applications and calculations. - Examples given include degrees of efficiency, ratio of data transfer rate to bandwidth in communication, relative product amount to energy use and environmental effects. An optimal condition corresponds to maximum result for a given resource/effort or vice versa. Conditions can only be derived using a specific singular target parameter.

Modeling in Engineering

• Mathematical models are crucial for analyzing and interpreting complex physical processes.
• These models are important for cross-disciplinary communication.
• Models are needed because most processes have molecular events that are not directly observable.
• In this context, six levels of model complexity are needed dependent on the level of detail needed in model development.

Course Topics 2: Thermal Separation Technologies

• Includes distilling, rectification, absorption, adsorption, extraction, drying, crystallization, and encapsulation of functional ingredients.
• These are examples of thermal separation technologies.

Unit Operations - Mass Transfer

• Unit operations reliant on mass transfer.
• Includes adsorption/desorption, sublimation/desublimation, absorption/desorption, distillation, evaporation/condensation, extraction, drying, and crystallization

Content – Lecture Outline

• The lectures cover introductory topics, diffusion coefficients, Fick's vs Maxwell Stefan, multi-component diffusion, heat transfer mechanisms, non-Newtonian media, fluid mechanics, balance equations, turbulent flow, and boundary layers.
• Other topics are thermal separation techniques, drying process, coupled heat and mass transfer, membrane separation, crystallization, chemical reaction engineering, residence time distributions, order of reactions, and combined mass and chemical reactions

Basic Literature

• A list of recommended books is given as references that students can use for further information

Transport Phenomena - Causes

• Heat transport includes heat conduction, convective heat transfer, and radiation.
• Mass transport includes mass conduction (diffusion), convective mass transport.
• Both heat and mass transport depend on driving forces (e.g., temperature gradient, concentration difference) and the mechanism of the processes occurring.

Applications Related to Mass and Heat Transfer

• Specific examples given include solid body drying, wet scrubber (air conditioning), CO2 separation (absorption and reaction), and particle dissolution. The slides include illustrative process diagrams.

Recapitulation: Stationary Transfer

• A diagram shows the linear dependency of concentration as it relates to the distance.

Mass Transport by Diffusion

• Diffusion as molecular movement between particles.
• Fick's Law is explained detailing the symbols used such as flux of molecules, diffusion area, concentration gradient and diffusion coefficient.

Driving forces and Transport Phenomena

• Fick's Law, Newton's shear stress approach and Fourier's Law are described with relevant equations pertaining to mass transport, momentum transport, and heat transport.

Gradient - Divergence

• Mathematical representation of gradient and divergence in three different coordinate systems (Cartesian, cylinder, and spherical).
• Definitions and equations relating to both gradient and divergence.

Derivation - Fickian law/Fourier law

• Derivations are provided for both Fick's and Fourier's Laws with geometric examples that are used.

Instationary Heat Conduction

• Differential equations for one and three dimensional instationary heat conduction.
• Focus on conditions in which the solutions of partial differential equations can be determined.

Instationary Heat Transfer

• Fourier's differential equation with temperature components in instances in which heat is occurring from one location to another in a complex way. If the system has constant material elements like λ then equations can be simplified.

Semi-Infinate Bodies (Neumann Solution)

• Analytical solution for temperature profiles with respect to space and time within a heating zone that is close to a body's surface. - Includes an example diagram with equations.

Gaussian Error Function

• Mathematical table for the Gaussian error function (erf(n)) used in temperature profile calculations.

Convective Heat Transfer - Semi-infinite bodies

• Numerical and analytical solutions for temperature changes within semi-infinite structures as heat is conducted in or out of the bodies.
• Includes examples of the calculation procedures in different situations.

Convective Heat Transfer – Semi-infinite Bodies in Contact

• Detailed solutions for heat transfer between semi-infinite bodies that are in contact.
• Includes tables of related physical quantities.

Convective Heat Transfer - Constant Temperature

• Solution of partial differential equations for heat transfer through a medium.
• Includes solutions via series of expressions in relation to heat and mass transfer

Heat Transfer/Diffusion

• Extensive discussion on square root relationships for penetration distance, required time, and surface area with respect to diffusion.

Instationary Diffusion - Fick's law

• Discussion of concentration-dependent diffusion in different conditions in relation to time.

Analogy of Mass and Heat Transfer

• Describes an analogy in how different types of substances transfer both heat and mass.

Diffusion in Non-Ideal Systems

• Discussion on deviations from ideal conditions, including discussions of multiphase interactions and effective diffusion coefficients.

Conditions of mass transfer

• Discusses how mass transfer can happen at different conditions given detailed explanations and examples of approaches to describing mass transfer from molecular diffusion to convective mass transport to flow conditions.

Mass transport by convection

• Mathematical analysis of mass transport due to convection.
• Defines phase boundary, concentration of a substance, spatial coordinate, molecular flow, boundary layer, and concentration at a phase boundary.

Laminar Flow in Boundary Layer

• Description of mass transport by molecular diffusion within a laminar flow boundary layer.
• Includes equations for calculating mass transfer coefficients.

Convective Mass Transport in Stationary Conditions

• Mathematical formulation and interpretation of convective transport in fixed conditions.
• Detail of ideal gas law, Raoultian Law, and molar concentration in relation to different components.

Prediction of mass transfer coefficient

• Numerical methods to calculate mass transfer coefficients.

Analogue Properties

• Comparison of heat and mass transport using mathematical expressions that relate to each other.

Analogy

• Summarizing table of heat and mass transport showing similar equations and concepts (different properties and analogues used)

Analogue Quantity

• Comparison of heat and mass phenomena with respect to free-flow and forced-flow, material properties, coupled heat and mass transport, and numerical example values.

Main Conditions for Diffusion

• Various types of diffusion processes described (equimolar, unidirectional, non-equimolar, multicomponent)

Analogy, Heat and Mass Transport

• Equations for heat and mass transport in different flow regimes (purely laminar, turbulent with boundary layers, start-up process, and frictionless turbulent).

Stefan Strom: Importance

• Diagram analysis of how the Stefan Factor is affected by differing Vapour pressures over a range of values.

Additional Notes

• The provided notes cover topics from various slides about food process design, including lecture outlines, mathematical analysis and descriptions, and applications of the concepts.