Continuous catalytic upgrading of fast pyrolysis oil using iron oxides in red mud

Abstract

A catalyst composed primarily of magnetite prepared from red mud via H2 reduction at 300 °C, simultaneously reduced acidity, allowed recovery of carbon, and generated upgradable intermediates from the aqueous fraction of fast pyrolysis oil in a “continuous” process.

Cost-effective upgrading of biomass pyrolysis oil using activated dolomite as a basic catalyst

“…Other attractive feature of the upgraded bio-oil collected after short reaction time (0.5 h) is its high content of ketones, mainly acetone (26 % at 400 ºC and 37 % at 500 ºC), 2-butanone (11-19 %) and cyclopentanones (17-30 %). This result suggests that the dolomite has great activity for ketonization of bio-oil oxygenates, through pathways similar to those proposed using a wide variety of catalysts for upgrading pyrolysis oils [27,29,30,40]. Also noteworthy is the presence of 7.3 % of aliphatic hydrocarbons (composed of linear C6-C12 alkenes and C8 cycloalkenes) in the upgraded bio-oil obtained at 500 ºC.…”

“…8). It should be noted that these reactions are promoted by the high concentration of water in the reaction medium [29,48,49], and also by the H2 coming from the dolomite activity for SR and WGS reactions (Eqs. ( 9)-( 10)).…”

“…Vapor-phase ketonization of carboxylic acids over a wide variety of metal oxides (e.g., TiO2, ZrO2, SiO2, Al2O3, MnO2, CeO2, CeZrOx) has attracted extensive attention [9,25,26]. However, most of the studies have focused on the conversion of pure oxygenates (bio-oil model compounds), and there are few studies that approach ketonization of oxygenates mixture (simulated bio-oil) and raw bio-oil [27][28][29][30]. Therefore, information regarding the interactions of acids with other raw bio-oil compounds is scarce.…”

The carbon deposits formed by reaction of a series of red mud samples with methanol

“…The total mass decrease can be explained by oxidation of the reduced phases generated by the reaction of RM7 and methane. 13 In this study, the slight increase can be attributed to oxidation of magnetite produced from precursor hematite or goethite phases. It is known that magnetite can be oxidized below 400 o C. 25 From 2 hours reaction time onwards, the carbon species were oxidized in two stages, which may mean that two different carbon species were generated during the methanol cracking process.…”

“…Red mud has been investigated for various applications, such as construction materials, [6][7] production of ceramics, 8 gas and water purification, 4,9-10 and catalysis. [11][12][13] Recent studies have demonstrated that red mud is catalytically active to produce carbon from different sources, such as methane, [14][15] ethylene, 16 ethanol, [17][18] associated petroleum gas, 19 and a crude untreated waste stream from bio-diesel production. 20 The resultant carbon materials can be used as functional materials, such as for treatment of metal-contaminated water, 21 whilst the co-product of hydrogen formed in the cracking of hydrocarbons can be used as fuel.…”