Hidrogeno-ekoizpena bio-oilaren erreformatze katalitikoaren bidez

The growing demand of H2 for its use as petrochemical raw material and clean fuel has boosted the development of processes for its production from alternative sources to oil, among which biomass has received special attention due to its availabil-ity and renewable nature. There is an increasing interest in the development of indirect routes for H2 production from biomass, via steam reforming of biomass-derived oxy-genated compounds. Indirect pathways to obtain hydrogen from biomass, such as the steam reforming of oxygenates derived from biomass, are these days in the spotlight. Among them, the so called bio-oil deserves special attention, due to its economic via-bility. Actually, delocalized production of bio-oil in biomass production plants allows for its subsequent transportation to centralized units for its further valorization. How-ever, problems caused by the pyrolytic lignin produced during this process need to be also considered, specially, the solid residue deposited on both the catalyst and the reac-tion setup when bio-oil evaporates. Scale up technology is deemed necessary in order to solve this drawback. Moreover, the development of an active, selective and stable catalyst is of the utmost importance towards achieving full viability of the process. In this piece of work, we aim at giving an overview on the main bio-oil reforming strate-gies in literature, with special emphasis on the results from our research group.; H2-aren eskariaren igoerak, petrokimikako lehengai eta erregai garbi gisa erabiltzeko, petrolioaz bestelako lehengaiak jatorri duten prozesuen garapena bul-tzatu du. Prozesu horien artean, biomasak arreta berezia bereganatu du haren erabilga-rritasunagatik eta berriztagarritasunagatik. Biomasatik H2-a lortzeko zeharkako bideek gero eta jakin-min handiagoa eragin dute, esate baterako, biomasatik eratorritako oxi-genatuen bidezko lurrun erreformatzeak. Horien artean, bio-oilak interes handia dauka, beste bideek baino bideragarritasun ekonomiko handiagoa izan baitezake. Izan ere, bio-oilak ekoizpen deslokalizatua izan dezake biomasaren ekoizpen-fokoetan eta on-doren, unitate zentralizatuetara garraia daiteke balioztatzeko. Dena dela, prozesu horre-tan kontuan hartu beharra dago lignina pirolitikoak sortzen dituen arazoak, zehatzago, erreakzio-ekipoan eta katalizatzailean depositatzen den hondakin solidoa bio-oila lu-rruntzen denean. Arazo hori gainditzeko, beharrezkoa da teknologia eskalagarria. Ho-rretaz gain, katalizatzaile aktibo, selektibo eta iraunkorren garapena funtsezkoa da pro-zesu horren bideragarritasuna lortzeko. Lan honetan, bibliografian dauden bio-oilaren erreformatzearen estrategia nagusiak aurkezten dira, ikerketa-taldearen emaitza origi-nalak nabarmenduz

Syngas Production through Dry Reforming of Raw Bio-oil: Effect of CO2/C Ratio

This study deals with the effect of CO2/carbon molar ratio (CO2/C) on syngas production in the dry reforming (DR) of real bio-oil with a NiAl2O4 spinel derived catalyst, which has high activity and H2 selectivity in the raw bio-oil reforming. The reaction tests were carried out at 700 ºC, steam/carbon (S/C) molar ratio of 0.4 (corresponding to the water contained in the bio-oil feed), space time of 0.25 gcatalysth/goxygenates, and CO2/C ratio of 0, 0.5 and 1. The results evidence a higher syngas yield in the DR reaction tests (88%, not dependent on CO2/C ratio) compared to the conventional steam reforming (SR, 76%) because of the increase in CO yield, which leads to a decrease in H2/CO ratio (from 1.8 in SR to 1.2 and 1 for CO2/C ratio of 0.5 and 1, respectively). For both CO2/C ratios positive CO2 conversions (22-24 %) and a reduction of CO2 emissions over SR are obtained. The characterization of spent catalysts by several techniques proves that the main cause of deactivation is coke deposition, that is mainly composed of structured carbon (filamentous carbon), with a small fraction of amorphous coke. The DR reaction tests lead to a noticeable higher deposition of filamentous carbon, which does not lead to a noticeable difference in the catalyst stability compared to SR, in spite of the significant higher amount of coke deposited (34 and 46 wt% for CO2/C ratios of 0.5 and 1, respectively) than in the SR (18 wt%)