Catalytic generation of hydrogen from biomass derived lactic acid via aqueous phase reforming

magistrsko delo

Monika Bosilj (Avtor), Andreja Goršek (Mentor), Zdravko Kravanja (Komentor), Thomas Aicher (Komentor)

Povzetek

Hydrogen production from aqueous phase reforming (APR) of organic acids in aqueous phase and from residue of a biomass decomposition process over 3 wt% Pt/ZrO2 has been studied in the absence and presence of barium ions. The results have been compared with Pt/TiO2, Pt/C and Ni/C catalysts. Having identified barium hydroxide as a promising reagent in combination with Pt/ZrO2 catalyst for the hydrogen production out of organic acids, the method for the lactic acid conversion was extended. Lactic acid (LA) was analysed as a major compound in an aqueous solution after a biomass digestion process with Ba(OH)2. Gaseous and aqueous products after APR reaction of LA mixture with barium hydroxide were identified by different analytical techniques. Gaseous products consisted mainly of permanent gases such as hydrogen, carbon dioxide and methane. The results showed that mixture of LA in combination with both barium hydroxide and Pt/ZrO2 catalyst had the highest hydrogen production rate and the highest selectivity to hydrogen, whereas low gaseous product amount were observed from mixture of LA and only barium hydroxide or Pt/ZrO2 catalyst. Methane and higher amount of carbon dioxide were detected in gas phase products particular in the presence of Pt/ZrO2 catalyst in the mixture. Aqueous products consisted mainly of pyruvic acid, acetic acid and salts, such as acetate and propionate. The complete conversion of LA after APR was reached in mixture of LA and Ba(OH)2∙8H2O over Pt/ZrO2 catalyst. Mixture of LA and Ba(OH)2∙8H2O or Pt/ZrO2 catalyst gave lower conversion of LA. Amount of gaseous products, selectivity to hydrogen and LA conversion were affected by higher reactant mixture concentration. In comparison to low concentrated mixtures, high concentrated mixtures contained larger amounts of barium but the same amount of Pt/ZrO2 catalyst. BET analyses showed much smaller pore volume of spent Pt/ZrO2 catalyst, which was used in APR reaction of high concentrated (1.5 mol/L) mixture. Therefore, lower gas product amounts, lower selectivity to hydrogen and only 63 % conversion of LA were effects of deactivated Pt/ZrO2 catalyst. The results showed that hydrogen generation from APR of LA and conversion of LA in aqueous phase are hardly influenced by the Pt/ZrO2 catalyst presence, which in combination with barium ions, promotes the catalytic APR reaction.

Ključne besede

biomass;hydrogen production;aqueous phase reforming;lactic acid;

Podatki

Jezik:	Angleški jezik
Leto izida:	2015
Tipologija:	2.09 - Magistrsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[M. Bosilj]
UDK:	604.4:662.6:579(043.2)
COBISS:	18470422
Št. ogledov:	1540
Št. prenosov:	135
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Slovenski jezik
Sekundarni naslov:	KATALITIČNO PRIDOBIVANJE VODIKA IZ BIOMASE PROIZVEDENE MLEČNE KISLINE Z REFORMIRANJEM V VODNI FAZI
Sekundarni povzetek:	Cilj magistrskega dela je eksperimentalna preiskava vpliva prisotnosti in odsotnosti barijevih ionov in začetnih koncentracij reaktantov na proces pridobivanja vodika z reakcijo reformiranja v vodni fazi (aqueous phase reforming, APR) iz organskih kislin z dodatkom 3 wt% Pt/ZrO2 katalizatorja. Organske kisline so bile proizvedene z dekompozicijo biomase v vodni fazi z Ba(OH)2. Rezultati APR reakcije za pridobivanje vodika z dodatkom Pt/ZrO2 so bili primerjani še z ostalimi rezultati APR reakcij z dodatkom različnih katalizatorjev, in sicer Pt/TiO2, Pt/C in Ni/C. Ugotovili smo, da se največ vodika proizvede iz organskih kislin v prisotnosti barijevega hidroksida in Pt/ZrO2 katalizatorja. Mlečna kislina je bila glavni produkt reakcije dekompozicije biomase z Ba(OH)2 v vodni fazi, zato je reformiranje mlečne kisline z Ba(OH)2 in Pt/ZrO2 katalizatorjem predstavljalo modelno reakcijo eksperimentalnih preiskav. Produkti v plinasti in vodni fazi so bili po APR reakciji mlečne kisline identificirani z različnimi analitskimi metodami. Plinasta faza produkta, ki je bila sestavljena predvsem iz H2, CO2 in CH4, je bila analizirana s plinsko kromatografijo. Najvišja selektivnost do H2 ter največja količina proizvedenega H2 iz mlečne kisline je bila dosežena z dodatkom Ba(OH)2 in Pt/ZrO2. Produkti v vodni fazi so bili predvsem piruvatna kislina, vinska kislina in soli, kot so acetati in propionati. Popolna pretvorba mlečne kisline je bila dosežena z dodatkom Ba(OH)2 in Pt/ZrO2 katalizatorja. Na nižjo pretvorbo mlečne kisline v raztopini vpliva odsotnost Ba(OH)2 ali Pt/ZrO2. Količina proizvedenih produktov v plinski fazi, selektivnost do H2 in pretvorba mlečne kisline so odvisni tudi od začetne koncentracije raztopine mlečne kisline. Bolj koncentrirane raztopine vsebujejo več barijevih ionov a enako količino katalizatorja, kar povzroči zamašitev por katalizatorja in posledično nižjo katalitično aktivnost ter manjšo količino proizvedenega H2.
Sekundarne ključne besede:	biomasa;proizvodnja vodika;reformiranje v vodni fazi;mlečna kislina;
URN:	URN:SI:UM:
Vrsta dela (COBISS):	Magistrsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	XII, 79 f.
ID:	8707289