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Olarte, Mariefel

Publications and source records attributed to Olarte, Mariefel.

11 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Co-Hydrotreatment of Pyrolytic Lignin and Waste Cooking Oil to Produce Hydrocarbons

The co-hydrotreatment of pyrolysis bio-oils and vegetable oils could facilitate the integration of bioderived fuels into existing fuel infrastructures without significant modifications. Co-hydrotreatment studies with different PL/WCO blend ratios (0, 10, 20, 30, and 40 wt %) were conducted over the NiMo/γ-Al 2 O 3 catalyst. The coke formation value for WCO was 0.7 wt % and ranged between 1.5 and 2.5 wt % with the increase of pyrolytic lignin in the blend. The data suggest that coke is formed from both the sugar- and lignin-derived oligomers since the coke yield reported in this study is comparable with the coke yield obtained by coprocessing the bio-oil fraction without light oxygenate compounds, based on previous studies. All blends are recommended for co-hydrotreatment based on coke yield. The resulting organic phase was distilled into hydrocarbons at <150 °C, 150 to 250 °C, and 250 to 350 °C. The organic product’s overall hydrocarbon distribution was strongly dependent on the pyrolytic lignin concentration. The yield of the distillation cut with a boiling point range between 250 and 350 °C was higher in the hydrotreated samples, with more than 20% during distillation. Two-dimensional GC×GC was used to determine carbon distribution on the combustibles. FTIR and UV fluorescence spectra showed that most feedstocks were converted to potential combustibles for transportation applications after hydrotreatment. The distillation cuts properties, such as density, viscosity, and surface tension, were reported and compared to transportation fuel properties. Hydrocarbon yields reveal the potential of cohydrotreatment to upgrade pyrolytic lignin into valuable products. Furthermore, these findings provide useful insights into utilizing pyrolytic lignin to produce promising combustibles suitable for transportation applications.

co-hydrotreatment↗
DOE OSTI2024

Co-hydrotreatment of Bio-oil and Waste Cooking Oil to Produce Transportation Fuels

This paper reports the co-hydrotreatment of the heavy bio-oil fraction with waste cooking oil (WCO) using NiMo/γ-Al 2 O 3 catalyst, followed by the distillation of resulting deoxygenated oil and the characterization of resulting fuel cuts. The heavy BTG bio-oil fraction was obtained by removing the very reactive light-oxygenated compounds via rotary evaporation, subsequently mixed with 1-butanol. The resulting oil was blended with WCO and subjected to a two-step co-hydrotreatment process. The first step, called “stabilization,” is aimed at saturating highly reactive hydrogen-deficient compounds. The second step, called “deoxygenation,” aimed to remove bio-oil oxygen, primarily as H 2 O. This study examined the impact of varying bio-oil concentrations (0, 10, 20, 30, 40 wt.% of WCO) on the upgraded oil's yield, composition, and fuel properties. The resulting hydrotreated oil was distilled into gasoline-range, kerosene-range, and diesel-range hydrocarbons at <150 °C, 150 to 250 °C, and 250 to 350 °C, respectively. The yield of the hydrotreated oil indicates that as the bio-oil concentration increases, the amounts of coke (0.7 to 2.4 %) and water (2 to 10 wt. %) increase while the organic layer yields decrease (80 to 63 %). The coke yield was comparable to the coke yield obtained when co-processing the pyrolytic lignin fraction. This suggests that coke is formed from both the sugar oligomers and the lignin-derived oligomers. The UV-fluorescence analysis on the hydrotreated oil shows that more polycondensed and conjugated ring compounds formed as the bio-oil concentration is increased. These compounds are precursors of coke. FTIR results showed that most raw materials were converted to biofuels after the hydrotreatment. To achieve less than 1 wt. % of coke yield, blends with up to 20 wt. % pyrolysis oil should be used. An increase in bio-oil concentration leads to a slight increase in gasoline yield and a decrease in kerosene and diesel yields. The identified carbon species found in the fuel cuts include n-paraffin, iso-paraffin, cycloparaffin, and aromatics. Further, the jet fuel cut (kerosene) was characterized by density, surface tension, and viscosity. Our product conforms to the standard specifications for sustainable aviation fuels (Jet A-1). Further research is suggested to fine-tune the operating parameters for achieving reduced coke yield and enhanced kerosene yield.

09 BIOMASS FUELS↗
DOE OSTI2024

pnnl/chemreasoner

ChemReasoner - Catalyst Discovery via Large Language Model-driven Reasoning

Choudhury, Sutanay↗
DOE OSTI2023

Theoretical Insights on the Fragmentation of Cellulosic Oligomers to Form Hydroxyacetone and Hydroxyacetaldehyde

The presence of heavy unknown oligomeric sugar products in bio-oil is evidenced in experimental results reported in the literature. In this paper, we study the fragmentation reactions yielding acetol and glycolaldehyde from oligomeric sugars following previous work on dehydration reactions to propose structures of these oligomers. Acetol and glycolaldehyde are primary products of cellulose fast pyrolysis but the fragmentation reaction mechanism of these compounds from oligomers merits further study. The density functional theory (DFT) approach was employed to study this reaction. Results revealed that acetol and glycolaldehyde fragments are favorably removed from the non-reducing end based on their thermodynamic stabilities. Theoretical FTIR and NMR spectra were calculated to aid in understanding the structures of the oligomeric sugars. Also, the thermodynamics and physical properties of these compounds were estimated using the Group Contribution Method (GCM). In conclusion, these properties are essential in the design of processing technologies and the upgrading of products.

10 SYNTHETIC FUELS↗
DOE OSTI2021

BETO 2021 Peer Review - Analytical Development and Standardization for Biomass-Derived Thermochemical Liquids

This project began in FY14 to address the lack of standard chemical characterization analytical methods for bio-oils. Bio-oils are very complex and present numerous analytical challenges; yet reliable chemical information (quantification of both individual compounds and chemical functional groups) is needed to inform upgrading research and refinery co-processing. In this project, analysis needs are first determined from engaging the bioenergy community. Next, standard methods are developed to meet these needs, and then subsequently validated via inter-laboratory studies. Methods that are successfully validated (< 10% variability) are then shared as Laboratory Analytical Procedures (LAPs), which are free and publicly available. We have been tracking LAP use and have seen sustained usage as evidenced by an average of 500 pages views and 100 downloads per quarter, demonstrating the value of these methods to the bioenergy community. LAP methods that are particularly useful and reliable will be chosen for the next-level of standardization through ASTM. We have recently achieved approval by ASTM for our carbonyl titration method. This method (ASTM E3146) is the first example of an ASTM standard solely focused on the chemical characterization of bio-oils. Work in this project is meeting the analysis needs of the bioenergy community and will ultimately help enable the commoditization of bio-oils.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2019

Hydrotreatment of pyrolysis bio-oil: A review

Fast pyrolysis is an effective process to convert more than 60 wt. % of lignocellulosic materials into a bio-oil that can be further hydrotreated for transportation fuel production. However, bio-oil is acidic, viscous, and chemically unstable due to its high oxygen content. Therefore, increasing attention has being paid to deoxygenation of bio-oil through catalytic hydrotreatment into a “drop-in” fuel has been gaining attention from researchers. The first section of this review is devoted to summarize our current understanding of bio-oil composition. Bio-oil hydrotreatment is typically conducted in two-steps. In the first step, known as stabilization, the reactive carbonyl and carboxyl functional groups are transformed into alcohols at a temperature between 373 and 573 K. In the second step, between 623 and 673 K, cracking and hydro-deoxygenation (HDO) occurs. The most common catalysts used in the stabilization step are noble metals (Pt, Ru, Pd) supported on carbon and metal oxides (TiO2, Al2O3, SiO2, Fe2O3, ZrO2). The most common catalysts for deoxygenation and hydrocracking are sulfided CoMo or NiMo. More recently transition metal phosphides and carbides have been shown to be active. The effect of hydrotreatment parameters and the main global reaction mechanisms are discussed. In the first section, we update the progresses made on bio-oil composition, followed by a detailed discussion on the role of heterogeneous catalysts. Many of the bio-oil hydrotreament studies in the literature are based on model compound results. The reactions revealed by such approach are summarized and discussed. Although these studies provide valuable information for developing upgrading strategies, bio-oil chemistry is difficult to describe by model compounds. Thus, we also reviewed a smaller number of hydrotreatment studies of pyrolysis oil fractions. The presence of several oxygenated functional groups (phenols, carboxylic acids, carbonyls, alcohols) in monomeric and oligomeric molecules is a major challenge to study hydrotreatment reactions. Under realistic industrial operational conditions undesirable polymerization and crosslinking reactions leading to catalyst deactivation are very important. In spite of the extensive work on bio-oil hydrotreatment, the nature of the reactions happening in these complex oils is still poorly known. Pyrolytic lignin and sugars have been identified as important contributors to coke formation. Both fractions can then undergo successful hydrogenation or hydrogenolysis over the catalysts. The review ends with a discussion on future prospects and challenges to hydrotreat pyrolysis oils. Because bio-oil is a liquid formed by hundreds of molecules covering a wide range of molecular weights and functionalities, it is very unlikely that a single hydrotreatment technology that makes a good use of each of its molecules could be found. In fact, current hydrotreatment schemes sacrifice some fractions (convert them into low value products) to maximize the conversion of others into fuel. Separation of bio-oil in fractions and processing of each of them via hydrotreatment or by other suitable technology at optimized conditions with well suited catalysts to obtain high value products seems to be the most promising path to reduce hydrogen consumption, coke formation and enhance the economic viability of bio-oil refineries.

Han, Yinglei↗