Course detail
Boilers
FSI-LK Acad. year: 2027/2028 Winter semester
The course deals with the design, construction and operation of steam boilers. It builds on the mass and heat balance of a boiler and on the general principles of design and verification thermal calculations. It covers in detail the furnace and its temperatures, heat transfer in the boiler, and the influence of fuel properties on the boiler concept and the choice of furnace type (grate, fluidized bed, pulverized fuel). The course further discusses the classification and concepts of boilers, from fire-tube boilers through water-tube drum boilers to once-through and supercritical boilers and waste heat boilers. A large part of the course is devoted to the individual heat transfer surfaces, i.e. the economizer, the evaporator system with the drum, the superheater and the air preheater, including their design, materials, calculation, operation and maintenance. The lectures conclude with boiler fittings and accessories (safety and control fittings, auxiliary fittings) and steam boiler control. In the exercises, students independently prepare a calculation and design proposal of a waste heat boiler downstream of a gas turbine.
Language of instruction
Czech
Number of ECTS credits
5
Supervisor
Department
Learning outcomes of the course unit
Students who complete the course are able to:
- formulate the mass and heat balance of a boiler, determine its losses and thermal efficiency, and perform a thermal calculation of the furnace,
- design and size the heat transfer surfaces of a boiler (economizer, evaporator, superheater, air preheater), including the selection of materials, – explain the function of the evaporator system with the drum, the boiler fittings, water treatment and the control loops of a steam boiler, and their importance for safe operation,
- compare boiler concepts (fire-tube, water-tube drum, once-through, gas-fired, biomass and waste, waste heat) in terms of fuel, efficiency and emissions, and justify the choice of concept for given conditions,
- propose measures to reduce boiler emissions (Low-NOx burners, selective catalytic reduction, flue gas treatment equipment) and assess their impact on boiler design and operation,
- independently prepare and defend a calculation and design proposal of a waste heat boiler downstream of a gas turbine.
Entry knowledge
Students are able to formulate mass and energy balances of an open system, work with the properties of water and steam (steam tables, h-s and T-s diagrams) and perform stoichiometric combustion calculations (combustion air and flue gas quantities, flue gas enthalpy). They are also able to determine convective and radiative heat transfer coefficients, calculate heat transfer through plane and cylindrical walls, and carry out a basic thermal design calculation of a recuperative heat exchanger. Students are familiar with the basic types of boilers and their arrangement at the level of a bachelor's degree in power engineering.
Rules for evaluation and completion of the course
The course is completed with a course-unit credit and an exam. Attendance at lectures and exerecises is optional.
The course-unit credit is awarded upon submission and presentation of the project by the deadline set by the teacher. The project is accepted if it contains all parts required by the assignment, the calculations are technically correct, and the student demonstrates during the presentation that they understand the chosen solution and can justify it. A project returned for revision may be resubmitted and presented again by the end of the examination period.
The project assessment does not count towards the final grade. The exam consists of a written and an oral part. The written part contains 4 equally weighted questions, each worth max. 25 points, i.e. max. 100 points in total. Students who obtain at least 50 points in the written part proceed to the oral part.
The oral part verifies whether the student understands the essence of the subject matter and is able to explain it; it is assessed on a scale of 0–100 points. The overall exam result is calculated as a weighted average: 70 % of the points from the written part and 30 % of the points from the oral part.
If the student obtains fewer than 50 points in the oral part, the exam is graded F regardless of the result of the written part.
The final grade corresponds to the ECTS grading scale according to Art. 14 of the BUT Rules for Studies and Examinations: A 90–100, B 80–89, C 70–79, D 60–69, E 50–59, F 0–49 points.
5 credits correspond to 130 hours of student workload (1 credit = 26 h): lectures 39 h, exercises 13 h, project work 40 h, continuous self-study 13 h, exam preparation 25 h.
Aims
The aim of the course is to prepare students for the independent design of steam boilers and for solving technical tasks related to their construction and operation.
Students who complete the course are able to:
- formulate the mass and heat balance of a boiler, determine its losses and thermal efficiency, and perform a thermal calculation of the furnace,
- design and size the heat transfer surfaces of a boiler (economizer, evaporator, superheater, air preheater), including the selection of materials,
- explain the function of the evaporator system with the drum, the boiler fittings, water treatment and the control loops of a steam boiler, and their importance for safe operation,
- compare boiler concepts (fire-tube, water-tube drum, once-through, gas-fired, biomass and waste, waste heat) in terms of fuel, efficiency and emissions, and justify the choice of concept for given conditions,
- propose measures to reduce boiler emissions (Low-NOx burners, selective catalytic reduction, flue gas treatment equipment) and assess their impact on boiler design and operation,
- independently prepare and defend a calculation and design proposal of a waste heat boiler downstream of a gas turbine.
Study aids
The following study materials are available to students in [the BUT e-learning system]:
* lecture presentations covering all topics of the syllabus,
* the project assignment, including instructions on its preparation, scope and required content,
* tables and diagrams needed for the calculations, in particular the properties of flue gas, air, water and steam.
The study programmes with the given course
Programme N-ETI-P: Power and Thermo-fluid Engineering, Master's
specialization ENI: Power Engineering, compulsory
Type of course unit
Lecture
39 hours, optionally
Syllabus
Teaching takes place in blocks. Lectures and exercises alternate in individual weeks of the semester according to the schedule below; the duration of each block is given in hours for each week. The specific dates of the blocks are published in the course timetable.
Week 1 (4 h): Introduction, overview of boilers. Basic mass and heat balance of a boiler, boiler losses and efficiency. General principles of boiler design, design and verification thermal calculation.
Week 2 (4 h): Furnace – basic properties, furnace temperatures, heat transfer in the furnace.
Week 3 (1 h): Influence of fuel on boiler design and choice of furnace type (grate, fluidized bed, pulverized fuel), influence of volatile matter, ash and water content in fuel.
Week 4 (4 h): Steam generator – arrangement of heat transfer surfaces. Feedwater system and feedwater control station. Economizer – design, materials, calculation, operation and maintenance.
Week 5 (4 h): Drum – function, design, fittings, steam purification, level control, thermal stress. Evaporator – natural and forced circulation, design of furnace walls, two-phase flow.
Week 6 (4 h): Superheater – design, materials, calculation, steam temperature control. Air preheater – design, materials, calculation, operation and maintenance.
Week 7 (2 h): Overview and classification of boilers. Fire-tube boilers – design and materials.
Week 8 (4 h): Once-through and supercritical boilers – concept, evaporator, advantages and disadvantages, materials.
Week 10 (4 h): Gas-fired boilers and waste heat boilers – classification by layout and number of pressure levels, fire-tube and water-tube gas-fired boilers. Main boiler components: Low-NOx burners, air system, pressure part, feedwater pumps, selective catalytic reduction (SCR), P&ID.
Week 11 (4 h): Biomass and waste boilers – grate boilers, fuel handling, types of grates (reciprocating, chain, vibrating), flue gas treatment section (separation, reactor, filter, induced draught fan), wood chip and straw boilers, waste incineration. Operating problems and boiler failures from practice.
Week 12 (4 h): Boiler accessories – safety and control fittings, auxiliary fittings, sootblowers. Steam boiler control (load, combustion, draught, feedwater, steam temperature). Materials for power engineering – a brief overview. Boiler project execution in practice – from the assignment to the handover, calculation and design software.
Exercise
13 hours, optionally
Syllabus
Exercises take place in blocks according to the schedule, see the lecture syllabus.
Week 3 (3 h): Waste heat boilers (HRSG) – combined cycle, operating modes with a gas turbine, design layout. Project assignment. Heat balance of the boiler, temperature–heat diagram, water and steam parameters at characteristic points, flue gas enthalpy, attemperation balance, heat duties of individual surfaces.
Week 7 (2 h): Design of an HRSG – pressure and non-pressure parts, modules, headers, finned tubes. Design of heat transfer surfaces – flue gas duct, tube arrangement, flow velocities, heat transfer, design of the superheater and other surfaces. Design of downcomers and risers.
Week 9 (4 h): Drum design – drum internals, load, retention time, operating levels. Selection of materials for heat transfer surfaces and fins. Determination of boiler dimensions, preparation of the drawing. Chemical and thermal water treatment.
Week 13 (4 h): Project presentation and submission.
Individual project consultations take place throughout the semester.