Mathematical model of pyrolysis process of plastic waste

Prvi dio rada bavi se općim karakteristikama pirolize i njezinim glavnim vrstama: termičkom i katalitičkom pirolizom, a spomenuta je i piroliza pomoću mikrovalova. Detaljno su opisani i reaktori koji se koriste kod pirolize plastičnog otpada te katalizatori korišteni kod katalitičke pirolize. Također su navedeni glavni nedostaci svake vrste pirolize. U drugom dijelu rada navedeni su postojeći matematički modeli procesa pirolize s pripadajućim formulama: neuralni neizraziti model, polinomni model, modeliranje gubitka mase, NRTL model koeficijenta aktivnosti, three lump model, model prijenosa topline, šestostupanjski model. Zadnji dio rada prikazuje rezultate simulacije procesa pirolize pri različitim temperaturama za tri vrste sirovina: čisti HDPE, mješavinu PP/PE i čisti PP. Može se zaključiti da udjeli produkata na kraju procesa ovise o vrsti sirovine, temperaturi procesa i vremenu zadržavanja. Ovi parametri odabiru se ovisno o željenim produktima. Na kraju rada je opisano postojeće postrojenje za pirolizu plastičnog otpada te svi njegovi dijelovi, a dana je i bilanca masenih i energetskih tokova.The first part of this thesis deals with pyrolysis in general as well as its main types: thermal and catalytic pyrolysis, and microwave pyrolysis is also mentioned. The reactors used for the pyrolysis of plastic waste as well as catalysts used in catalytic pyrolysis are described in detail. The main drawbacks of each of the pyrolysis types are also mentioned. In the second part of the thesis, the existing mathematical models of the pyrolysis process with the corresponding formulas are described: neural fuzzy model, polynomial model, modelling mass loss, NRTL activity coefficient model, three lump model, heat transfer model, six step model. The last part of the paper shows the results of pyrolysis simulation at different temperatures for three types of raw material: pure HDPE, PP/PE mix and pure PP. Product shares at the end of the process depend on the type of raw material, process temperature and retention time. These parameters are selected depending on the desired product. At the end of the paper, an existing plant for the pyrolysis of plastic waste and all its components have been described, and there is also the mass and energy balance