Hidrotermična pretvorba bučne pogače v sekundarne produkte

diplomsko delo univerzitetnega študijskega programa I. stopnje

Nino Škafar (Avtor), Mojca Škerget (Mentor), Maja Čolnik (Komentor)

Povzetek

Živimo v dobi energetske preobrazbe, kjer si prizadevamo najti trajnostne alternative fosilnim gorivom. S prehodom na trajnostne vire se zmanjša onesnaževanje okolja, saj se odpadki ponovno uporabijo, namesto da se zažgejo ali odvržejo. Eden izmed potencialnih odpadkov je odpadna biomasa, saj je bogata s komponentami, ki se lahko ponovno uporabijo. Bučna pogača je stranski produkt, ki nastaja med pridelavo bučnega olja in se običajno zavrže ali uporabi kot krma za živali. Vsebnost dragocenih hranilnih snovi, kot so beljakovine, vlaknine, fenoli in materiali, jo naredi uporabno tudi za druge namene. Predstavlja obetaven vir za proizvodnjo biogoriv, kot so bioolje, bioplin ali biooglje. V okviru diplomskega dela smo raziskovali pretvorbo bučne pogače v pod- in nadkritični vodi in analizirali nastale produkte. Hidrotermično pretvorbo smo izvajali v visokotlačnem in visokotemperaturnem reaktorju pri 300 °C, 350 °C in 400 °C ter reakcijskih časih 30, 60, 90 in 120 min. Produkti omenjene pretvorbe so bili plinska, oljna, vodna in trdna faza. Najvišji izkoristek oljne faze smo dobili pri 300 °C in 30 min (73,04 %), zato smo pri teh pogojih dodatno izvedli še hidrotermično pretvorbo predhodno ekstrahirane bučne pogače s Soxhletovo ekstrakcijo (odstranitev maščob iz materiala). Ugotovili smo, da s povečevanjem temperature in reakcijskega časa naraščajo izkoristki plinskih faz (4,12 % do 27,92 %), medtem ko izkoristki oljnih (od 73,04 % do 55,34 %) in vodnih faz (od 16,41 % do 10,40 %) upadajo. Izkoristki trdnih faz pa so se gibali med 5 % in 7 %. Med vsemi rezultati najbolj odstopajo rezultati s prehodno obdelano bučno pogačo s petroletrom, kjer smo po hidrotermični razgradnji določili tudi najnižji izkoristek oljne faze (45,42 %) in najvišjo vsebnost TC v vodni fazi (25,81 g/L). Z GC-MS analizami oljnih faz smo ugotovili, da prevladujejo spojine, ki vsebujejo dušik (metil pirazin, 2-pirolidon, indol, oktadekanamid), medtem ko te spojine pri trdnih fazah s temperaturo in časom izginjajo iz FTIR spektrov. S povečevanjem temperature in podaljševanjem reakcijskega časa se rahlo zmanjšuje tudi koncentracija furfuralov v vodnih fazah, medtem ko so bile na splošno vsebnosti TC v vodnih fazah kar visoke (med 11 in 26 g/L). Najvišjo HHV vrednost (28,63 MJ/kg) v oljnih fazah pa smo določili pri 400 °C in 60 min. Z GC-MS analizami plinskih faz smo ugotovili, da pri vseh temperaturah in časih prevladuje ogljikov dioksid, katerega delež se s povečevanjem temperature znižuje, medtem ko se deleži drugih plinov, kot so metan, etan, propan, izobutan, zvišujejo. Na podlagi rezultatov smo ugotovili, da hidrotermična pretvorba bučne pogače prestavlja uspešen in okolju prijazen pristop za pridelavo sekundarnih produktov, ki se lahko ponovno uporabijo.

Ključne besede

odpadna biomasa;bučna pogača;pod- in nadkritična voda;hidrotermični procesi;biogoriva;diplomske naloge;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2025
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[N. Škafar]
UDK:	66.061.4:665.117(043.2)
COBISS:	248086787
Št. ogledov:	0
Št. prenosov:	9
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Hydrothermal conversion of pumpkin seed cake into secondary products
Sekundarni povzetek:	We live in time of energy transition, in which we are endeavouring to find sustainable alternatives to fossil fuels. Switching to sustainable energy sources reduces pollution by reusing waste instead of burning or throwing it away. One possible type of waste is biomass, which is rich in reusable components. Pumpkin seed cake is a by-product of pumpkin oil production that is usually thrown away or used as animal feed. Due to its content of valuable nutrients such as proteins, fibres, phenols and other substances, it can also be used for other purposes. It is a promising resource for the production of biofuels such as bio-oil, biogas or biochar. In this work, we investigated the conversion of pumpkin seed cake in subcritical and supercritical water and analysed the resulting products. The hydrothermal conversion was carried out in a high-pressure and high-temperature reactor at 300 °C, 350 °C and 400 °C with reaction times of 30, 60, 90 and 120 minutes. The products of this conversion included gas, oil, aqueous and solid phases. The highest yield of the oil phase was obtained at 300 °C and 30 minutes (73.04 %), which is why we also carried out a hydrothermal conversion of previously defatted pumpkin seed cake using Soxhlet extraction (removal of fats from the material) under the same conditions. It was found that the yields of the gas phases increased with increasing temperature and reaction time (from 4.12 % to 27.92 %), while the yields of the oil phases (from 73.04 % to 55.34 %) and aqueous phases (from 16.41 % to 10.40%) decreased. The yields of the solid phases were between 5 % and 7 %. Of all the results, the greatest deviation was observed in the pumpkin seed cake pretreated with petroleum ether, which had the lowest yield of the oil phase (45.42 %) and the highest total carbon (TC) content in the aqueous phase (25.81 g/L). GC-MS analysis of the oil phases revealed a dominance of nitrogen-containing compounds (methylpyrazine, 2-pyrrolidone, indole, octadecanamide), while these compounds disappeared from the FTIR spectra of the solid phases with increasing temperature and reaction time. The concentration of furfurals in the aqueous phases decreased slightly with increasing temperature and reaction time, while the total carbon content in the aqueous phases remained relatively high (between 11 and 26 g/L). The highest calorific value (HHV) of the oil phase (28.63 MJ/kg) was determined at 400 °C and 60 minutes. GC-MS analysis of the gas phases showed that carbon dioxide was predominant at all temperatures and times, but its proportion decreased with increasing temperature, while the proportions of other gases such as methane, ethane, propane and isobutane increased. Based on the results, we concluded that the hydrothermal conversion of pumpkin seed cake is a successful and environmentally friendly approach to produce secondary products that can be reused.
Sekundarne ključne besede:	waste biomass;pumpkin seed cake;sub- and supercritical water;hydrothermal processes;biofuels;
Vrsta dela (COBISS):	Diplomsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	1 spletni vir (1 datoteka PDF (IX, 41 str.))
ID:	27122124