Kinetika toplinske razgradnje miješanog plastičnog otpada

master's thesis

• Title (english): Kinetics of thermal decomposition of mixed plastic waste
• Author: Josipa Dželalija
• Mentor: Zlata Hrnjak-Murgić (mentor)
• Committee member: Zlata Hrnjak-Murgić (predsjednik povjerenstva)
• Committee member: Zvonimir Katančić (član povjerenstva)
• Committee member: Vanja Kosar (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2019-09-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Polimerni otpad uspješno se reciklira, može se koristit kao vrlo vrijedna sekundarna sirovina, a zbog svoje visoke energetske vrijednosti pogodan je i za termičku obradu. Čisti homopolimeri relativno jednostavno se mogu reciklirati dok izazov predstavljaju mješavine polimera te se stoga za takvu vrstu otpada kao potencijalni način obrade nameće piroliza. U ovom radu korišteni su najčešće upotrebljavani polimerni materijali: polietilen visoke gustoće (HDPE), polietilen niske gustoće (LDPE), polipropilen (PP) i polistiren (PS) i njihove mješavine. Ispitana je toplinska postojanost čistih homopolimera kao i njihovih mješavina (Mix 1-5) te uz prisustvo Fe/Al2O3 katalizatora (Mix/F 1-5), termogravimetrijskom analizom (TGA). Uzorcima su odreĊene temperature; početne razgradnje (T90), pri maksimalnoj brzini razgradnje (Tmax) kao i ugljenizirani ostatak (mr) te brzina maksimalne razgradnje (rmax). Također, praćena je i kinetika toplinske razgradnje istih uzoraka, pri čemu su mjerenja provedena pri 4 različite brzine zagrijavanja (5, 10, 15, 20 °C/min). Ispitivanim uzorcima analizirana je kinetika toplinske razgradnje primjenom KAS modela gdje je razmatran mehanizam razgradnje, tj. pojava paralelnih reakcija razgradnje. Određene su energije aktivacije (Ea) toplinske razgradnje izokonverzijskom KAS metodom. Iz rezultata može se zaključiti da porastom brzine zagrijavanja kod svih uzoraka raste toplinska postojanost. Iz rezultata kinetičke analize i energija aktivacije (Ea) uočena je pojava paralelnih, slijednih i revezibilnih reakcija u procesu toplinske razgradnje koje se pojavljuju kao posljedica različitog sastava i strukture polimera. Zbog pojave paralelnih reakcija vrijednosti Ea za Mix/F 3, 4 i 5 ne odgovaraju stvarnim energijama aktivacije već su umanjene, odnosno uvećane.

Abstract (english)

Plastic waste can be successfully recycled because it can be used as a very valuable secondary raw material and it is also suitable for thermal treatment due to its high energy value. Pure homopolymers are relatively easy to recycle while the mixtures of polymers are great challenge, and therefore for this type of waste as a potential treatment is pyrolysis. In this paper commonly used polymers were studied: high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP) and polystyrene (PS) and theirs mixtures. The thermal stability of pure homopolymers and their blends (Mix 1-5) as well as blends in the presence of Fe/Al2O3 catalysts (Mix / F 1-5) was investigated, using thermogravimetric analysis (TGA). The thermal stability of these samples was investigated by determination of initial degradation temperature (T90), temperature at maximum degradation rate (Tmax) as well as carbonized residue (mr) and maximum degradation rate (rmax). Also, the kinetics of their thermal decomposition was monitored, with measurements performed at 4 different heating rates (5, 10, 15, 20 °C/min). The kinetics of thermal decomposition of the investigated samples was analyzed using the KAS model and the mechanism of decomposition was considered, i.e. the occurrence of parallel decomposition reactions was studied. The activation energies (Ea) of thermal decomposition were determined by the isoconversion KAS method. From the results it can be concluded that with the increasing heating rate increase of thermal stability for all samples is observed. From the results of kinetic analysis and activation energy (Ea) the occurrence of parallel, sequential and reversible reactions in the process of thermal decomposition has been observed as a consequence of the different composition and structure of the polymers. Due to the occurrence of parallel reactions, the values of Ea for Mix /F 3, 4 and 5 do not correspond to the actual activation energies, they are slightly decreasing or increasing.

• Keywords: polimerni otpad; zbrinjavanje otpada; termogravimetrijska analiza; kinetika toplinske razgradnje
• Keywords (english): polymer waste; waste management; thermogravimetric analysis; kinetics of thermal degradation
• Language: croatian
• URN:NBN: urn:nbn:hr:149:569466
• Project: Number: IP-2018-01-3200; Title: Napredni nositelji energije u oporabi plastičnog otpada; Acronym: NEOPLAST; Leader: Daniel Rolph Schneider; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Environmental Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka ekoinženjerstva (magistar/magistra inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-02-17 10:02:04