Poboljšanje termodinamičke iskoristivosti parnoturbinskog dijela kombiniranog postrojenja primjenom organskih radnih medija

doctoral thesis

• Title (english): Thermodynamic efficiency improvement of combined power plant's bottom cycle by using organic working fluids
• Author: Stjepko Katulić
• Mentor: Mislav Čehil (mentor)
• Committee member: Daniel Rolph Schneider (predsjednik povjerenstva)
• Committee member: Antun Galović (član povjerenstva)
• Committee member: Veljko Filipan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2016-12-14, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Process Energy Engineering
• Universal decimal classification (UDC): 621 - Mechanical engineering. Nuclear technology. Machinery ; 51 - Mathematics

Abstract

U radu je opisan matematički model koji je korišten za potrebe optimiranja parnoturbinskog dijela kombiniranog postrojenja. Generator pare na otpadnu toplinu modeliran je na način da različiti krugovi pare, uključujući i međupregrijanje prvog kruga, čine skup izmjenjivača u kojima se može izmjenjivati toplinski tok između dimnih plinova i radnih. Izmjenjivači mogu biti u međusobnom paralelnom i serijskom razmještaju. Za radni medij prvog kruga odabrana je voda dok je u drugom krugu pare, osim vode, korišten radni organski fluid. Provedena je termodinamička i eksergoekonomska optimizacija rada postrojenja, gdje su optimizacijske varijable bile razmještaj izmjenjivačkih površina unutar generatora pare na otpadnu toplinu, te parametri radnog medija svakog kruga pare i međupregrijanja. Kod termodinamičke optimizacije funkcija cilja je bila maksimiranje termodinamičke iskoristivosti parnoturbinskog postrojenja, dok je kod eksergoekonomske optimizacije funkcija cilja bila minimiziranje eksergijskih gubitaka i minimiziranje investicijskih troškova. Kao optimizacijski alat koristili su se genetski algoritam i gradijentne optimizacijske metode. Matematički model je napravljen u programskom paketu Matlab. Dokazano je da se korištenjem paralelnih i serijskih razmještaja izmjenjivačkih površina, te korištenjem vode u prvom krugu pare i organskih radnih medija u drugom krugu pare, mogu postići više vrijednosti termodinamičke iskoristivosti parnoturbinskog postrojenja.

Abstract (english)

In this work a mathematical model of a steam cycle (bottom cycle, Rankine cycle), which is part of combined cycle power plant, was made. The heat recovery steam generator is modeled in such a way that various pressure levels, including reheating of first pressure level, form a heat exchangers network in which heat can be exchanged between flue gases and working fluids in their parallel and serial configuration. Water is chosen as the working fluid of the first pressure level, while for the other pressure levels an organic fluid is chosen as the working fluid. A thermodynamic and exergoeconomic optimization was conducted. Optimization variables were configuration of heat exchangers inside the heat recovery steam generator and operating parameters of working fluid of each pressure level and reheating. In the case of thermodynamic optimization objective function is represented by the maximum thermodynamic efficiency of the bottom cycle, but in the case of exergoeconomic optimization objective function is represented by minimal exergetic losses and minimal investment costs. The genetic algorithm and gradient optimization methods were used as optimization tools. The mathematical model was made in Matlab software package. In comparison to other available works it is shown that by using parallel and serial configuration of heat exchangers and by using water in the first level pressure and organic working fluids in second pressure level better thermodynamic efficiency of the bottom cycle can be achieved.

• Keywords: generator pare na otpadnu toplinu; kombinirano postrojenje; parnoturbinsko postrojenje; genetski algoritmi; optimizacija; organski fluidi
• Keywords (english): heat recovery steam generator; combined cycle power plant; steam turbine plant; genetic algorithm; optimization; organic working fluids
• Language: croatian
• URN:NBN: urn:nbn:hr:235:760892
• Study programme: Title: Mechanical Engineering and Naval Architecture; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje tehničkih znanosti (doktor/doktorica znanosti, područje tehničkih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-04-14 20:25:34