Course detail

Mass Transfer Processes

FSI-KDP Acad. year: 2027/2028 Winter semester

The production of many goods we rely on – cooking oil, petrol, instant coffee, pharmaceuticals or fruit spirits – depends on mass transfer processes. The study of these processes matters for process engineering and for a range of related fields.

The course covers mass transfer processes and their application in the principal process operations: distillation, absorption, extraction, drying, crystallisation, adsorption and membrane separation. The opening part introduces the mechanism of diffusion and the description of phase equilibria in mass transfer processes. The following part is devoted to the calculation of material and heat balances of equilibrium stages, of mass transfer equipment and of complete technological units. The closing part covers individual equipment types with a focus on determining their main balance and design parameters.

The course includes an individually assigned semester project in which the student carries out a design calculation of a selected mass transfer apparatus. A process simulator may be used as a supplementary tool for verifying the results.

Language of instruction

Czech

Number of ECTS credits

5

Supervisor

doc. Ing. David Jecha, Ph.D.

Department

Institute of Process Engineering

Entry knowledge

Before enrolling in the course, the student is able to:

  • set up and solve the material and enthalpy balance of process equipment and of a simple technological line under steady state;
  • use the expressions of mixture composition (mass, molar and relative fractions) and convert between them;
  • explain the state behaviour of gases and liquids and the concepts of saturated vapour, partial pressure and Raoult's and Dalton's laws;
  • determine thermodynamic quantities (enthalpy, specific heat, latent heat) from tables and diagrams;
  • describe the basic principles of heat transfer and design a simple heat exchanger;
  • solve systems of linear equations and work with the derivative and the integral of a function of one variable;
  • evaluate data and construct a graph in a spreadsheet application.

These skills are acquired mainly in the courses KBP – Balancing of Process and Energy Systems, KS1 – Thermodynamic Engineering, KTP-A – Heat Transfer Processes, KHL – Hydraulic Processes and KMP – Mechanical Processes.

Rules for evaluation and completion of the course

Conditions for the course-unit credit

The course-unit credit requires active participation in the seminars and submission of the semester project. Attendance at seminars is compulsory and is checked; at most two absences are tolerated. For a missed seminar the student submits a written elaboration of the problems solved and presents it to the teacher. The semester project is assigned individually and is submitted through the e-learning course by the deadline announced at the beginning of the semester. Attendance at lectures is recommended.

Examination

The examination is combined and consists of a written and an oral part.

The written part lasts 90 minutes and contains three calculation tasks covering material and heat balances, the graphical determination of the number of theoretical stages (McCabe–Thiele, triangular diagram) and design calculations of equipment. Only writing materials and a calculator may be used. The required tabulated data (molar masses, equilibrium data) and blank equilibrium and triangular diagrams form part of the assignment. Admission to the oral part requires at least 50 % of the points from the written part.

The oral part consists of three questions covering the theoretical basis of mass transfer, phase equilibria and the individual separation operations, including questions related to the problems solved in the seminars and to the semester project.

Final classification

The final assessment is the weighted average: the course-unit credit (semester project and seminar work) 10 %, the written part of the examination 30 % and the oral part of the examination 60 % (three questions, 20 % each).

Passing the examination requires at least 50 points out of 100 in the overall assessment. The total is converted into an ECTS grade in accordance with the BUT Study and Examination Rules (A 100–90, B 89–80, C 79–70, D 69–60, E 59–50, F below 50).

Aims

On successful completion of the course, the student is able to:

Knowledge

  • explain the mechanism of molecular and convective diffusion, describe the two-film theory of mass transfer and explain the meaning of the diffusion coefficient and of the mass transfer coefficients;
  • describe the phase equilibria of vapour–liquid, liquid–liquid and sorption systems and explain their representation in equilibrium, enthalpy and triangular diagrams;
  • compare the principles, fields of application and design arrangements of distillation, absorption, extraction, drying, crystallisation, adsorption, membrane separation and electrolysis, and justify the choice of a separation operation for a given task.

Skills

  • set up and solve the material and heat balance of an equilibrium stage, of an apparatus and of a complete technological line for a given composition, flow rates and operating conditions;
  • determine the number of theoretical stages by graphical methods (McCabe–Thiele, triangular diagram) for binary distillation, absorption and extraction, determine the minimum solvent quantity and the minimum reflux, and construct the feed line for a given feed parameter;
  • design the main balance and construction parameters of a mass transfer apparatus (number of actual trays, height and diameter of a packed column, choice of packing, energy consumption), assess the result critically and present it in a written report.

Study aids

Study aids are available in the BUT e-learning system (Moodle) in the course Mass Transfer Processes (KDP):

  • a course handbook with organisational information and the conditions for completing the course;
  • lecture materials for all topics of the course;
  • seminar assignments and materials for the solved problems;
  • blank equilibrium, enthalpy and triangular diagrams for graphical solutions;
  • the assignment distribution and the template for the semester project;
  • supplementary materials (Gibbs adsorption isotherm, solution of the pressure in a crystalliser).

The study programmes with the given course

Programme N-PRI-P: Process Engineering, Master's, compulsory

Type of course unit

 

Lecture

26 hours, optionally

Syllabus


  1. Introduction to mass transfer processes. Classification of mass transfer operations and their role in the process industry.

  2. Fundamentals of mass transfer. Molecular and convective diffusion, Fick's law, two-film theory, mass transfer coefficients.

  3. Phase equilibria. Vapour–liquid, liquid–liquid and sorption equilibria. Equilibrium, enthalpy and triangular diagrams.

  4. Material and heat balance of mass transfer equipment and of a technological line. Evaporators, application to sugar factory technology.

  5. Material and heat balance of binary distillation, the McCabe–Thiele method, feed line, minimum and operating reflux.

  6. Batch and multicomponent distillation. Batch distillation and the Rayleigh equation, steam distillation. Multicomponent mixtures – key components and the principles of determining the number of theoretical stages (overview).

  7. Absorption and desorption. Material balance, minimum solvent quantity, determination of the number of stages and of the column height.

  8. Packings and internals of distillation and absorption columns. Tray efficiency, column hydraulics, pressure drop, determination of the column diameter.

  9. Humid air and the Mollier diagram, material and heat balance of a theoretical and a real dryer, drying kinetics.

  10. Liquid–liquid extraction. Single-stage and multistage countercurrent extraction, solution in the triangular diagram, solvent recovery.

  11. Adsorption from gases and liquids. Adsorption isotherms, breakthrough curves, determination of the number of theoretical stages.

  12. Solubility and supersaturation, crystallisation kinetics, material and heat balance of a crystalliser, types of crystallisers.

  13. Membrane processes. Microfiltration, ultrafiltration, reverse osmosis, membrane gas separation. Principle, module arrangement and fields of application.

Exercise

26 hours, compulsory

Syllabus


  1. Revision of the material and enthalpy balance of process equipment.

  2. Calculation and estimation of diffusion coefficients in gases and liquids.

  3. Calculations of molecular diffusion and mass transfer.

  4. Construction and reading of phase diagrams, vapour–liquid equilibrium calculations.

  5. Material and heat balance of binary distillation.

  6. Determination of the number of theoretical stages by the McCabe–Thiele method, feed line, reflux.

  7. Absorption I – material balance, conversion of absolute and relative concentrations, operating line.

  8. Absorption II – minimum solvent quantity, number of theoretical stages, height of a packed column.

  9. Drying – balance of a theoretical dryer, work with the Mollier diagram.

  10. Extraction I – single-stage extraction, solution in the triangular diagram.

  11. Extraction II – multistage countercurrent extraction, solvent recovery.

  12. Crystallisation and adsorption – material and heat balance of a crystalliser and the yield; determination of the number of theoretical stages in adsorption.

  13. Membrane processes and electrolysis – balance of a membrane module, calculation of retention and permeate flux; balance of an electrolyser.


The semester project with an individually assigned separation task is set and consulted throughout the semester; a process simulator may be used as a supplementary tool for verifying the results.