Czech

6

doc. Ing. David Jecha, Ph.D.

Institute of Process Engineering

Before starting the course, the student should be able to:

• differentiate and integrate functions of one variable and solve simple ordinary differential equations,
• use the ideal gas equation of state, apply the first and second laws of thermodynamics to simple processes with an ideal gas and define the main thermodynamic quantities,
• write the stoichiometric equation of a chemical reaction, perform stoichiometric calculations and convert between basic ways of expressing concentration.

This knowledge corresponds to a bachelor’s degree in mechanical, power or chemical engineering (in particular courses in thermomechanics and chemistry).

Course completion

The course is completed by a course-unit credit and an examination. Only students who have been granted the course-unit credit may register for the examination.

Attendance

Attendance at lectures is recommended. Attendance at exercises is compulsory and is checked by an attendance sheet. A student may have at most 2 absences without compensation. In very exceptional cases, a greater number of absences for serious reasons may be tolerated, but any additional absences must be properly excused and compensated for in a manner determined by the instructor.

Requirements for the course-unit credit

The course-unit credit is granted if all three requirements are met:

• fulfilment of compulsory attendance at exercises,
• passing the credit test, i.e. obtaining at least 50 out of 100 points,
• submission of the semester project and its acceptance and approval by the teacher.

Credit test

The written test consists of computational problems practised in the exercises (100 points in total) and takes place at the end of the teaching period. Permitted aids are a calculator and one A4 sheet with the student’s own formulas and notes. The duration is set by the teacher according to the difficulty of the test but does not exceed 120 minutes. Students are entitled to a maximum of two resit attempts.

Semester project

The semester project is a group computational project (groups of usually 3–5 students) focused on the mass and heat balance of selected units of a real technological process. The assignment, submission deadline and instructions are published in the e-learning course at the beginning of the semester. The main tasks are solved progressively in the exercises.

The output is a technical report in an editable format (docx). For each task it contains the assignment and the solution with a verbal description of the procedure, numbered formulas and equations, balance tables, labelled graphs, units of quantities and a brief summary of results. It may include solving a selected task with an artificial intelligence tool and critically comparing the result with the group’s own solution.

The project is graded A–F according to the correctness and completeness of the solution and its formal quality. A project with substantial shortcomings is returned for revision. Comments on an accepted project must be incorporated and the revised version submitted before the examination.

Examination

The examination is written, in the form of a test in the e-learning system (Moodle). It takes place in person in a computer room under supervision. The test usually contains 40 questions covering the lectures and exercises (theoretical questions and computational problems), and the time limit is usually 40 minutes. Only a calculator is permitted; internet searching and other aids are not allowed.

Final grading

The final grade is based on the sum of points (maximum 100 points plus, where applicable, bonus points for activity in lectures):

• examination test: 0–70 points (percentage score of the test × 0.70); passing the examination requires at least 50 % of the test points, otherwise the final grade is F,
• semester project: 0–10 points (grade A = 10, B = 7, C = 3, D = 1, E = 0),
• credit test: 0–20 points, calculated as (test points − 50) / 50 × 20, rounded to whole points; passing at the first resit reduces this by 5 points, passing at the second resit reduces it by 10 points,
• bonus: 0–6 points for active participation in lectures (in-class quizzes).

The grade is determined according to the ECTS scale (Art. 14 of the BUT Study and Examination Rules): A 90–100 points, B 80–89, C 70–79, D 60–69, E 50–59, F less than 50 points.

The aim of the course is to enable students to perform mass and energy balances of physico-chemical processes in process equipment using properties of substances under real conditions.

A student who successfully completes the course is able to:

• select a suitable model of state behaviour (ideal gas equation of state, cubic equations of state, theorem of corresponding states) and calculate the density and other state variables of real gases, liquids and their mixtures,
• determine transport and thermal properties of substances and their mixtures (viscosity, thermal conductivity, diffusivity, heat capacity, enthalpy) using tabulated data and estimation methods,
• set up and solve the mass and energy balance of a steady-state process with a chemical reaction, including conversion of units (SI and imperial), concentrations and flow rates, heat of reaction (Hess’s and Kirchhoff’s laws), higher and lower heating values and combustion air demand,
• calculate the energy demand of gas compression and expansion and the change in gas temperature in adiabatic and isenthalpic processes,
• calculate the change in entropy and Gibbs energy for processes with real substances, determine the equilibrium constant of a reaction and its temperature dependence, and determine the saturated vapour pressure of a pure substance,
• prepare, as a team, a technical report with the balance of a process unit and assess the physical plausibility of the results, including results obtained with artificial intelligence tools.

All study materials are available in the e-learning course of KS1 (BUT Moodle) for the given academic year:

• presentations for all lectures,
• materials for the exercises (problem assignments, calculation materials),
• the semester project assignment, instructions for its preparation and submission and the necessary thermodynamic data.

The examination also takes place in the e-learning course.

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

26 hours, compulsory

The exercises take place in a computer room and follow the lectures. Exercises with typical computational problems alternate with exercises in which students work in groups on the tasks of the semester project (e.g. hydrogen production by steam reforming of natural gas) using a spreadsheet and other computational software. The order of topics may shift slightly depending on the semester calendar.

1. Introduction to the semester project: formation of groups, instructions, description of the technology, initial data of the assignment.


2. Typical problems: units and their conversion, ways of expressing concentrations, state behaviour of ideal gases.


3. Semester project: processing capacity of the unit, balance of the inlet stream, compression of natural gas.


4. Semester project: composition of the mixture of natural gas and hydrogen, mixing with superheated steam, use of steam tables.


5. Typical problems: state behaviour of ideal and real gases and their mixtures (e.g. van der Waals, virial and Redlich-Kwong equations, compressibility factor, Amagat’s law).


6. Typical problems: density of gases and liquids, ideal gas processes and the first law of thermodynamics, adiabatic compression and expansion.


7. Semester project: enthalpy calculations, change in reaction enthalpy and its temperature dependence (Kirchhoff’s law).


8. Semester project: composition of the reaction mixture at the outlet of the primary reformer, total heat absorbed in the reformer furnace.


9. Semester project: composition of wet combustion air, combustion of gaseous fuel, heat balance of the reformer furnace, emission concentrations in the flue gas.


10. Typical problems: entropy, Helmholtz and Gibbs energy, heat of reaction and combustion, heating value.


11. Semester project: equilibrium constant, equilibrium conversion and equilibrium composition of the reaction mixture (calculation in mathematical software).


12. Semester project: completion of the heat balance of the reformer furnace, pipe sizing; semester project consultations.


13. Credit test.