Ketal Sugar Conversion Into Green Hydrocarbons by Faujasite Zeolite in a Typical Catalytic Cracking Process

Abstract

Fluidized catalytic cracking (FCC) converts hydrocarbons in the presence of a catalyst based on faujasite zeolite (USY and REY). While hydrocarbon is poorly reactive, biomass and its derived compounds are highly functionalized and not suitable to a typical FCC process. To overcome this limitation biomass was first converted into a dense and stable bio-crude composed mainly of ketal-sugar derivatives by using acetone in diluted acid. Here, a representative compound of this bio-crude, 1,2:3,5-di-O-isopropylidene-α-D-xylofuranose (DX) in n-hexane, was converted by USY and a commercial FCC catalyst containing USY, at 500°C, in a fixed bed and fluidized bed reactors, respectively. Faujasite Y is very efficient in converting DX. More than 95% conversion was observed in all tests. Over 60 wt.% was liquid products, followed by gas products and only around 10% or less in coke. The higher the catalyst activity the greater the aromatics in the liquid products and yet higher coke yields were observed. In particular, simulating more practical application conditions: using deactivated catalyst in a fluidized bed reactor, improved green hydrocarbons production (mono-aromatic up to 10 carbons and light hydrocarbon up to eight carbons) and unprecedented lower coke yield (≈5 wt.%) for bio-feeds. The present results further suggest that catalyst will play a primary role to convert the bio-crude into target hydrocarbons and overcome the transition of a non-renewable to a renewable refinery feed.

Conversion of Sugar Diacetyls to Bio-Hydrocarbons by the Catalytic Cracking in a Fixed Bed with Fresh and Deactivated Beta Zeolite

“…The amount of coke can be reduced by hydrothermal treatment of Y zeolites, reducing the number of acid sites. A reduction of coke 15 wt% to 8 wt% was observed with steam-treated USY when compared to fresh USY in the mixture of 30% DX / n-hexane [2]. Nonetheless, compared to fresh Beta zeolite, HUSY produced a coke yield greater than 50% under the same test conditions.…”

“…The cracking of fresh Beta was compared with those previously published using zeolites HUSY and HZSM-5 for cracking DX in a fixedbed reactor [2,16]. Table 4 summarizes the results of three types of catalysts using the same experimental conditions: 10 wt% DX in nhexane mixture and 400 mg of catalyst (WHSV 20 h − 1 ) at 500 • C. The liquid product is the total liquid collected, including the unreacted nhexane.…”

“…It has a low density (~ 0.1 g.cm − 3 ) and can undergo degradation under ambient conditions [1]. Sugarcane bagasse when subjected to specific conversion processes generates a high density bio-oil (~1.1 g. cm − 3 ) [2]. This bio-oil is still a mixture of biopolymers which contains a large number of carbon-oxygen bonds, making it highly reactive [1].…”

“…This fact favors DX in the competition for active sites of the zeolite. Therefore, DX is able to produce a larger range of products compared to n-hexane [2].…”

Hydrodeoxygenation of Xylose Isopropylidene Ketal Over Pd/HBEA Catalyst for the Production of Green Fuels

“…The former produced mainly aromatics and light olefins. The latter produced aliphatic, cyclic, and aromatic hydrocarbons (Batalha et al, 2014, Batalha et al, 2017Pinto et al, 2019a, Pinto et al, 2019bPereira et al, 2020, Pereira et al, 2021. Further, the wide variety of metal/support catalysts used in the HDO process is an advantage since it enables the conversion of different biomassderived molecules into green fuels.…”