Search

Tema ovog diplomskog rada je energetska i eksergetska analiza jednog kogeneracijskog postrojenja snage 20 MW koje snabdijeva potrošače s 24 t/h srednjetlačne i 34 t/h niskotlačne pare. U sklopu diplomskog rada detaljno je objašnjeno što kogeneracijska postrojenja predstavljaju, koje su njihove moguće izvedbe, koji su najbitniji dijelovi, gdje se primjenjuju te kakve su njihove emisije u okolinu. Također, rad sadrži i klasičan analitički proračun pripadnog kogeneracijskog postrojenja čiji su rezultati uspoređeni s rezultatima koji su dobiveni simulacijom u računalnom programu EBSILON Professional te na temelju kojih su kasnije napravljene energetska i eksergetska analiza postrojenja. Nakon energetske i eksergetske analize u računalnom programu EBSILON Professional napravljena je analiza emisije dimnih plinova iz postrojenja u ovisnosti o promjeni određenih ulaznih parametra tj. pri različitim režimima rada te je napravljena analiza na koji način funkcionalnost pojedinih toplinskih potrošača utječe na ukupnu iskoristivost postrojenja iz čega je na kraju i izvučen ukupni zaključak., The task of this thesis is the energy and exergy analysis of a 20 MW cogeneration plant that supplies consumers with 24 t/h medium pressure and 34 t/h low pressure steam. As part of the thesis, it was explained in detail what cogeneration plants are, what their possible variations are, what are the most important parts, where they are used and what are their emissions into the environment. Also, this thesis contains a classic analytical calculation of the mentioned cogeneration plant, the results of which were compared with the results obtained by simulation in the computer program EBSILON Professional, on the basis of which the energy and exergy analysis of the plant was later made. After the energy and exergy analysis, in the computer program EBSILON Professional, an analysis was made of flue gas emissions from the plant depending on the change of certain input parameters, i.e. at different operating modes, and an analysis was made of how the functionality of individual heat consumers affect the overall utilization of the plant, from which the overall conclusion was drawn.

Разработана энергосберегающая технология двухстадийной газификации мелкодисперсной биомассы для когенерационных установок малой мощности на базе ДВС. Приведены результаты экспериментальных исследований технологи двухстадийной газификации биомассы. Представлены результаты оценки эффективности работы ДВС на различных видах топлива. Разработана технологическая схема когенерационной установки «газогенератор+ДВС» и проведена оценка эффективности работы на основе эксергетического и экономического анализа., Розроблена енергозберігаюча технологія двохстадійної газификації дрібнодисперсної біомаси для когенераційних установок малої потужності на базі ДВЗ. Приведені результати експериментальних досліджень технології двохстадійної газифікації біомаси. Представлені результати оцінки ефективності роботи ДВЗ на різних видах палива. Розроблена технологічна схема когенераційної установки «газогенератор+ДВЗ» та проведена оцінка ефективності роботи на основі эксергетичного і економічного аналізу., A two-stage fine biomass gasification process for the low - power generation plants based on ICE, providing the tar content in the producer gas of no more than 7.1 mg/m3n that meets the requirements of the ICE producers was developed. Based on the results of experimental studies of the two-stage fine biomass gasification process, the effective process regimes were determined. The optimal range of the specific air flow, which provides a stable process of oxidative biomass pyrolysis in a dense layer at the pyrolysis temperature not exceeding 800oC is 25.0 55.0 m3/(m2 h).Efficiency of the oxidative pyrolysis process reaches 98.0% taking into account the disposal of all heat flows. Efficiency of the coke residue gasification process without the use of sensible heat of the producer gas is on average 78.0%. Using the sensible heat of the producer gas allows to improve gasification process efficiency to an average of 96.4%.Numerical and theoretical studies of gas ICE operation have shown that the gas ICE operation on the producer gas with a calorific value of 7.6 MJ/m3 is optimum. In this case, the fall of ICE effective power is 16.0%, and the cost of electric power generation is 0.39 UAH/(kW∙h). The results of studies have also shown that increasing the natural gas proportion in a mixture of more than 40.0% is not desirable, since it leads to higher cost of electric power generation up to 1.04 UAH/ (kW∙h) that corresponds to the cost of electric power from the external power system.Exergy analysis of a cogeneration plant has shown a high value of total exergy efficiency of 45 %, while exergy efficiency of individual circuit elements, such as a pyrolyzer and gasifier reaches 96 %, and the "ICE-generator" unit - 91 %. Such values of efficiency are caused by deep disposal of all heat flows in the circuit.

Limitations of traditional first-law analysis, based upon unit-performance characteristics coupled with energy balances, are not a serious drawback when dealing with familiar systems. However, when dealing with more uncongenial, complex ones, it provides incomplete insight for such evaluation. These limitations come from the fact that first-law analysis does not indicate the sources or magnitudes of entropy production. An evaluation of plant performance will usually require a comparison of the thermodynamic performance of specific apparatuses or unit operations with available data from previously built plants. Therefore, exergy analysis has appeared to be very useful, providing information not just about magnitudes of losses, but also their distribution throughout the system. Such analysis which is not only useful at the level of apparatuses or unit operations but also at higher system levels e.g. for the comparison of overall plant performance (total system) or the performance of subsystems is the best method for indicating where research resources can be directed to best advantage.