In this study, we introduce a novel method for distinguishing among allotropic forms of carbon using laser-induced breakdown spectroscopy (LIBS) in air. We used the time evolution of CN and C2 molecular emission spectra to characterize various carbon allotropes, including graphite, fullerene, nanotubes, and amorphous carbon. To differentiate among these carbon samples, we employed principal component analysis (PCA). Our findings reveal significant differences in the plasma molecular emission of various carbon-based materials, offering new insights into their characterization. Notably, we observed strong emission signals from the (1-0), (0-0), and (0-1) C2 bands across all carbon allotropic forms during the early stages of plasma formation (less than 2 mu s). In contrast, aromatic hydrocarbon samples exhibited more pronounced emissions at later moments in the plasma (around 4 to 12.8 mu s). Overall, our time-resolved LIBS approach, combined with chemometric tools, provides a reliable and rapid way of identifying different allotropic forms of carbon.

This perspective paper explores accelerated mineralization technology to capture and generate value-added products while managing greenhouse gas emissions to support long-term environmental and energy goals. Mineralization, also known as mineral sequestration or mineral carbonation, involves the reaction of alkaline materials with CO2, mimicking natural weathering processes. In this reaction, gaseous CO2 interacts with calcium- or magnesium-bearing compounds (such as oxides, hydroxides, or silicates) in the presence of moisture, forming stable Ca/Mg carbonates. The presence of water or moisture accelerates the dissolution of Ca- or Mg-containing compounds to release Ca2+ and Mg2+ ions needed for reacting with CO2 to produce the respective solid carbonates. These carbonated products have lower free energy of formation, allowing CO2 to be permanently stored over geological time scales. Accelerated mineralization significantly enhances reaction rates, reducing processing times from days or decades to mere minutes or hours through carefully tuned process conditions (e.g., grinding, temperature, and pressure), additives, or solvents. Both direct and indirect carbon mineralization methods can be applied to manage three industrial waste streams: alkaline solid residues, wastewater, and CO2-containing flue gas. A bibliometric analysis revealed that the foundational mechanistic principles of carbonation/mineralization reactions were established between the 1990s and early 2000s. More recent studies (from the late 2000s onward) have expanded these insights, focusing on advanced material characterization, novel CO2 mineralization strategies, and pilot- and demonstration-scale implementations. While accelerated mineralization shows significant promise for CO2 capture, utilization, and storage, several challenges remain, broadly categorized into feedstock selection, process optimization, and product development. Feedstock variability strongly influences the mode of operation and final product applications. Techno-economic assessments indicate that the value associated with producing CO2- and silica-based products has a significant impact on the commercialization potential of a technology. Advancing novel chemical pathways for energy- and material-efficient carbon mineralization and high-value product applications will be crucial to enhance the viability and commercialization of these technologies.

CO2-based hydroesterification is an attractive route to produce value added ester compounds, which could replace widely used CO-based hydroesterification processes if sufficient catalytic technologies are developed. One path to CO2-based hydroesterification could proceed through an organoformate intermediate, which is then used in olefin hydroesterification to generate the desirable esters. This route opens the possibility of creating a net CO2-based hydroesterification process using tandem catalytic systems for CO2 hydrogenation to organoformate paired with formate-olefin hydroesterification. The tandem use of tripodal phosphine ruthenium(II) and 1,2-bis(di-tert-butylphosphinomethyl)benzene palladium catalysts were found to successfully produce methyl nonanoate from CO2, H2, methanol and 1-octene in a single-stage batch process. The CO2-based hydroesterification catalysis efficiency was found to be largely limited by the productivity of organoformate generation and competitive 1-octene reduction. Catalytic yields of methyl nonanoate can be enhanced by adjustments in reaction procedures, including the use of a two-stage batch reaction process or delayed introduction of 1-octene, achieving a yield of up to 32 %. Under select conditions, control experiments indicate yields of methyl nonanoate can be improved to ca 75 %. Preliminary studies indicate significant interplay between the two ligands employed in the molecular tandem catalytic systems and establish the first catalytic protocol for the selective CO2-based hydroesterification of olefins via organoformates.

There are significant barriers to successfully simulating asphaltene precipitation behavior. First, the accurate representation of specific asphaltenes is challenging due to their intrinsic complexity, and second, the size of the systems can limit the analysis of the temporal evolution to a few tens of nanoseconds when atomistic simulations are used. We present an approach to overcome these two barriers by integrating asphaltene mixtures built to match average properties with coarse-grained simulations. The asphaltene behavior is studied as toluene is replaced by n-heptane in a stepwise fashion, resembling the asphaltene titration. Three different asphaltene model mixtures (virgin Asphaltenes A1 and A2 and processed Asphaltenes B) were built to match the average properties of real asphaltenes. The results showed that coarse-grained simulations allowed longer run times and length scales than previous atomistic modeling, extending from a few nanoseconds to an equivalent of 0.75 mu s. Additionally, numerical calculations captured the impact of changes in the asphaltene aggregation mechanisms. Specifically, the virgin materials showed an overall lower aggregation percentage and lower cluster formation (monomer, dimer, and trimer) with varying shapes. Conversely, the processed asphaltenes showed a 7-fold increase in aggregation percentage through pi-pi stacking via their large aromatic cores. Compared with Turbiscan precipitation experiments, our simulations showed good qualitative alignment for both virgin asphaltene A1 and processed asphaltene B. Significant deviations are observed for virgin asphaltene A2, which is attributed to the difference in heteroatomic functional groups. These findings highlight the critical influence of heteroatomic functionalities on asphaltene aggregation behavior and emphasize that reliable molecular characterization data is essential for developing simulations that accurately match experimental observations.

The characterization of nanoparticles (NPs) in hydrocarbon matrices using single particle inductively coupled plasma mass spectrometry (spICP-MS) is underdeveloped. There are less than ten publications using spICP-MS in hydrocarbon matrices, and none have applied the technique to determine NP concentration and size distribution in asphaltenes after in-situ upgrading of heavy oils via solvent deasphalting. To our knowledge, no studies have used spICP-MS to track the nature of NP additives in the asphaltene fraction in hydrocarbons without adulteration of the sample. Particle number concentrations (PNC) derived from spICP-MS in hydrocarbon matrices are reported for the first time. Fe2O3 PNC increased by an order of magnitude, and NiO PNC increased 28 % compared to samples without additives, indicating that NPs were reasonably well-dispersed in the asphaltenes. Ionic concentrations were higher for Ni than Fe, which showed negligible changes in all samples. Here, we report the lowest size detection limits recorded for Fe2O3 NPs (32 nm +/- 1 nm) using spICP-MS in hydrocarbon matrices. Further, NiO and Fe2O3 NP sizes matched the initial sizes added to the oil before precipitation, providing evidence that the nature of the NPs does not change after deasphaltation and subsequent mixing with asphaltenes. This study expands our understanding of the interactions between metal NPs and asphaltenes when used as coprecipitants during in situ upgrading of heavy crude oil.

This perspective from members of the Energy & Fuels Division (ENFL) Industry Committee of the American Chemical Society (ACS) discusses the ENFL's role and challenges to foster a sustainable and equitable energy future by promoting research and technological advancements in energy production, storage, and utilization. Using bibliometric techniques, the current trends are presented in non-renewable and renewable energies, energy storage and grid modernization, hydrogen technologies, and carbon capture, utilization, and storage (CCUS). Recent International Energy Agency (IEA) projections indicate that 2023 global investments in clean energy increased by 17% to $1.7 trillion. However, conventional non-renewable sources still account for over 80% of global energy consumption, a share projected to peak near 2030. Continued robust growth in clean energy investments and capacity expansions in 2024 has shown solar photovoltaic (PV) and wind energy driving a substantial rise in renewable capacity. Nevertheless, conventional non-renewable sources still dominate global energy consumption. While renewable liquids from biomass remain limited, renewables are projected to supply only a modest fraction of the total energy demand by the decade's end. Despite these trends and the practical limitations of producing renewable liquids from biomass, renewables are projected to account for 20% of final energy consumption by 2030, up from 13% in 2023. The importance of sustained investment in clean energy technologies and the adoption of innovative materials for energy applications is reflected in the ACS symposia during the spring and fall national meetings, which showcase novel applications and developments in these fields. We conclude by discussing how the ENFL continued efforts to foster interdisciplinary collaboration and support groundbreaking research can drive the energy and fuels sector toward more sustainable processes, an imperative for accelerating the global energy transition.

Predicting the petroleum coke or petcoke morphology tendencies of Delayed Coking feeds is paramount to optimizing refinery operation and profitability. Herein, we report a new analytical methodology employing cross-polarized light optical microscopy (CPL-OM) of Microcarbon Residue Test (MCRT) cokes, followed by image segmentation and statistical analysis to determine several structural parameters, i.e., average area, average Feret maximum, and percentage of isochromatic domains with Feret maximum <8 mu m (Feret is defined as the maximum distance between the two parallel planes of a given coke particle). Several advantages over previous CPL-OM methods include using more extensive data sets and machine-learning software to accurately segment images to yield better statistics, eliminating iso-chromatic domains on edge to reduce error, and stitching multiple images to account for larger domains. The new CPL-OM-image segmentation-statistical analysis procedure was effectively used to determine the influence and predict the morphology of MCRT cokes based on Delayed Coking feed properties (C7-asphaltenes percentage/MCRT percentage ratio and the asphaltene solubility parameter) and in blends of vacuum resids. The structural parameters Feret Max. Percentage <8 mu m and average area showed excellent agreement within the errors of the technique. This technique represents a convenient analytical tool to qualitatively rank Delayed Coking feedstocks in terms of coke morphology tendencies.

In the oil sand literature, the deposits containing organics associated with solids and insoluble in toluene are often referred to as toluene-insoluble organic material (TIOM). In this work, we call these materials toluene insolubles (TI) and clarify what TIOM means. Our focus in this work is to determine the chemical composition of the organic portion of the TI obtained from the extraction of fouling deposits collected from a heat exchanger unit of a refinery. Analysis of TI using thermogravimetric analysis (TGA), optical microscopy, inductive coupling plasma (ICP), and X-ray diffraction (XRD) showed that these materials are composed of both organic and inorganic solids/clay minerals. Using an accelerated solvent extraction (ASE) unit, the TI fraction was sequentially solvent-extracted using methylene chloride/methanol (9:1, at 110 degrees C/1000 psi) and acetonitrile CH3CN (ACN, at 130 degrees C/1000 psi). The extracted fractions were then analyzed by using high-resolution mass spectrometry (HRMS) and Fourier transform infrared (FTIR). The results showed that the extracted materials were mainly organic polymers consisting of a variety of polyethers used as chemical additives in the oil industry. The analysis by atmospheric pressure photoionization (APPI) in positive ion mode and electrospray ionization (ESI) in positive and negative ion modes revealed that besides the predominant polyether polymer in the form of ethylene oxide (EO) and propylene oxide (PO), there are also condensed aromatics, pyridine, alkylpyridines, sulfonates, low-carbon low-double bond equivalent (DBE) species with one heteroatom, and acidic species. A subsequent analysis of the blank solvent obtained from the ASE unit by HRMS showed that no polyether polymers were present, indicating that these polymers are part of the foulant deposits. To obtain more structural information on the organic fraction, the TI sample was subjected to pyrolysis gas chromatography-mass spectrometry (GC-MS) between 300 and 600 degrees C. Compositional analysis revealed that the volatile organic fraction of the TI is composed mostly of polar components with oxygen and nitrogen functionality, including phenols, indoles, alkylpyrroles, aldehydes, and carboxylic acids. These products are most likely from the decomposition of polyethers as well as nonylphenols used as chemical additives. The presence of intact nonylphenol indicates the desorption of polar molecules from the surface of clays/minerals during pyrolysis. The results of this work have demonstrated that fouling deposits of a heat exchanger formed by organic molecules associated with inorganic solids are not only derived from the original oil but also derived from chemical additives that are used during oil production/processing.

The use of NiO nanoparticles as asphaltene co-precipitant additives is studied to improve the upgraded oil's properties and potentially reduce the solvent-to-oil ratio for the in-situ upgrading of heavy oils via solvent deasphalting. Asphaltene content, solubility profile, and C7-deasphalting laboratory experiments were carried out to evaluate the efficiency of the nanomaterial. Results showed that nickel oxide nanoparticles increased the amount of asphaltenes in the 15-18% range with respect to the case without additive at the same solvent-to crude ratio. In the presence of the NiO nanoparticles, improvements on the upgraded crude oil properties were found with an average 17.1 degrees API gravity (16% increase) and a viscosity of similar to 2370 cSt (similar to 16% reduction) vs. the case without additive. These results demonstrate the usefulness of using nickel oxide nanoparticles to further enhance the upgraded crude oil properties for heavy oil upgrading via solvent deasphalting. Based on elemental analysis and spectroscopic techniques (scanning transmission electron microscopy with high angle annular dark field detection, energy dispersive X-ray analysis, Mid-and Far-FT-IR, and X-ray photoelectron spectroscopy), it was found that NiO nanoparticles acted as nucleation sites (agglomerants). A carbon-containing layer from the asphaltene fraction encapsulates the nickel oxide nanoparticles. A plausible mechanism for the interaction of the nanostructured NiO with the C7-asphaltenes was proposed that involves the formation of nanosized Ni-Ocarboxylate or phenolate species on the surface of the nickel oxide nanoparticles.

Understanding vanadium and nickel distributions in asphaltene fractions have significant commercial importance throughout the petroleum value chain and the potential use of heavy feedstocks as a precursor of carbonbased materials, such as carbon fibers. This work extends our previous studies and aims to characterize volatile and non-volatile vanadium and nickel distributions by selective separation of n-heptane asphaltenes obtained from two Venezuelan heavy crude oils and the NIST Standard Reference Material (SRM) 8505. Asphaltenes were separated by extrography, i.e., adsorption on SiO2 and subsequent extraction with acetone, heptol (n-heptane/toluene 1:1 vol), and a mixture of toluene, THF, and methanol (TTM). The results suggest that their solubility and aggregation strongly correlate to a higher hydrogen deficiency and increased heteroatom levels. The qualitative analysis of the spent silica gel, containing irreversibly-adsorbed asphaltenes, by Light-Induced Breakdown Spectroscopy, suggests that regardless of the solvent power used during the extraction, strong chemisorbed Ni and V species remain on the SiO2, presumable associated with porphyrin molecules present on such feeds. High-Temperature Gas Chromatography coupled with Inductively Coupled Plasma Mass Spectrometry (HTGC-ICP-MS) showed that vanadium and nickel compounds have boiling points starting at 1050 degrees F. Quantification of the V-content below 1300 degrees F for the Venezuelan crude 1 indicated that the acetone fraction contains a large amount of distillable vanadium (similar to 62 %wt.). Interestingly, whole/unfractionated asphaltenes revealed only 47% of distillable vanadium, which suggests that the extrography method can obtain asphaltene fractions with "improved" properties (weaker aggregation, increased solubility, and lower boiling points). The characterization by atmospheric pressure photoionization Fourier Transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS) and HTGC-ICP-MS revealed that the acetone asphaltene fractions have a higher relative abundance of vanadyl porphyrins (with and without sulfur) than heptol and TTM.

After selective solvent extraction, the volatile and non-volatile vanadium and nickel distributions for two Venezuelan heavy crude oils and the NIST Standard Reference Material SRM 8505 were determined for the Entrained n-pentane (C5) maltenes, In-between C5-C7 asphaltenes, and n-heptane asphaltenes. The fractions were analyzed via the asphaltene solubility profile, size exclusion chromatography (SEC), High-Temperature Gas Chromatography coupled with Inductively Coupled Plasma Mass Spectrometry (HTGC-ICP-MS), and atmospheric pressure photoionization Fourier-transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS). Results showed that petroleum elution is strongly correlated to high hydrogen deficiency and increased heteroatom levels. The solubility decreased in the following order: Entrained C5 Maltenes, In-between C5-C7 asphaltenes, and C7 asphaltenes. Qualitative HTGC-ICP-MS shows that 51V traces of the first two asphaltene fractions showed a bimodal (Venezuelan crude oil 1 and NIST SRM 8505) or a multimodal distribution (Venezuelan crude oil 2). On the other hand, the 51V signal intensities for C7 asphaltenes were the lowest among all samples studied. FT-ICR MS revealed that the chemistry of vanadyl and nickel porphyrins is multimodal in terms of DBE. N4O1V1 and N4O2V1 classes exhibited abundant homologous series with DBE values of ?22; when sulfur was incorporated, e. g., N4O1S1V1 class, the DBE increased by 4?6 units. Ni-containing porphyrins showed two major homologous series, pointing toward a bimodal chemical nature. We hypothesized that this compositional feature could be why the bimodal and multimodal distributions of boiling points were found in the studied heavy crude oil fractions.

Downhole RF heating continues to be the interest of the petroleum industry because of its advantages over conventional forms of heating. Previous results have shown that without a low-loss dielectric zone (LLZ) around the downhole RF emitter, none of the available linear dipole antennas can work efficiently, and most of the energy is absorbed preferentially in a few meter radius around the radiating well and will not penetrate substantially into the reservoir. To circumvent this problem, low-dielectric materials were proposed, which are composed of a solid mixed with an appropriate binder. These materials were selected to have low dielectric properties so that the RF absorption is minimized, and at the same time, low porosity to prevent water invasion during the RF heating operation. Four solids, Ottawa sand, solvent deasphalted tar, Poly(p-phenylene sulfide) (PPS) and Polyether ether ketone (PEEK) and four binders (polydicyclo pentadiene (DCPD) and phenol-formaldehyde resins (Novolac), a C-Class cement slurry, and a foamed cement) were evaluated by measuring their dielectric properties (dielectric constant and loss tangent) in the frequency range 1 - 2000 kHz and temperatures between 25–200°C. All four solids have low RF absorption as well as low porosity (<1%), and those values did not change significantly with temperature. Also, smaller dielectric properties were found for DCPD and Novolac than those found for the cement materials, and the DCPD binder has a dielectric constant almost half and a loss tangent one order of magnitude lower than those measured for the Novolac resin. Three different designs for the construction of LLZ were considered, which included underreaming the oil well, squeezing a solid-containing binder downhole, and creating a casing-less completion. Numerical simulations show that the use of a low-loss zone around the central emitter leads to a very much improved energy and temperature distribution, and higher penetrations (~12 m) than the case without it.

Engineered iron oxide (Fe3O4) nanoparticles (NPs) were synthesized with a silica shell using a modified alkylsilane approach with o-xylene, as a hydrocarbon media, and transmission electron microscopy (TEM) and single-particle inductively coupled plasma mass spectrometry (spICP-MS) were used to determine the particle size of the Fe3O4 core diameter. In contrast, mass concentrations of the Fe3O4 particles were determined using spICP-MS, using helium (He) as a collision gas to control spectral interferences from ArO and CaO on Fe at m/z 56. Different cell gas flow rates (3, 3.5, and 4 mL/min) and NP’s solution dilution factors from 1:20,000 up to 1:60,000 were investigated; He flow rate of 4 mL/min and a dilution factor of 1:20,000 were found as optimum. The spICP-MS method was calibrated by using gold nanospheres (polystyrene-coated) in toluene as reference material. For the engineered Fe3O4 nanoparticles, TEM. Results gave a (63 ± 6 nm) value for the Fe2O3 core diameter, while spICP-MS was 61.1 ± 4.5 nm (n = 36), demonstrating the excellent agreement among methods. The method was applied for the analysis Fe oxide NPs in petroluem hydrocarbon materials and data compared with TEM. Two standard reference materials (SRMs); NIST 2717a sulfur in residual fuel oil and NIST 8505 vanadium in crude oil were selected. spICP-MS results agreed pretty well among these techniques. These findings suggest that spICP-MS could be useful to characterize Fe-containing particles in complex solution media, such as petroleum hydrocarbons. Graphical abstract

Thermal cracking (TC) of the Athabasca vacuum residue (ATVR) and its deasphalted product [deasphalted oil (DAO)] was studied. A comparison of conversion and product properties between TC and ultradispersed catalytic steam cracking (CSC) upgrading of both feedstocks is also reported, using K-Ni catalysts. Thermal conversions with stable products for the deasphalted fraction (DAO), reached 20% (w/w) higher values than the ATVR. DAOCSC provided 8% (w/w) increased conversion compared to DAOTC, with stable products. Higher thermal conversions for the DAO compared to the vacuum residue were explained in term of the better properties determined for the asphaltenes produced in DAO upgrading, i.e., higher hydrogen content and better solubilization properties due to lower molecular sizes, solubility parameters, and aromaticities. A definitive link between the nature of produced asphaltenes and products stabilities, as measured via P-value, was found. Higher DAO-steam catalytic conversions with stable products were also obtained and rationalized based on the occurrence of water splitting into *H and *OH radicals and hydrogen production from steam reforming/steam cracking reactions occurring during CSC processing. The inhibition of hydrocarbon free radical recombination (coking) by *H capping and hydrogenation facilitated by Ni catalysts are believed key reactions occurring, leading to better DAO product properties. Exploratory evidence gathered with the NiCeMo CSC-catalyst for whole bitumen processing added support to the later findings, i.e, olefin production inhibition was evidenced, indirect evidence of hydrogenation occurrence. A convenient field upgrading process that avoids distillation or separation (deasphalting) carried out at low T, P is, thus, envisaged.

Nitrogen is one of the hardest heteroatoms to remove from petroleum and its fractions. For this reason, nitrogen speciation has useful applications in feed reactivity to hydroprocessing and understanding catalyst deactivation. In the first part of this chapter, the objective is to characterize the nitrogen species present in the asphaltenes of vacuum residues to gain an understanding of the processability of these feedstocks to hydroprocessing. The results by X-ray photoelectron spectroscopy and mass spectrometry (MS) showed that the hydrodenitrogenation rate constant is inversely proportional to the percentages of pyrrolic nitrogen in the asphaltenes and whole residue. The correlations were relatively weak (0.42 and 0.71, respectively), which was attributed to differences in the degree of aromatic condensation, size, and alkyl-substitutions on the N-aromatic rings of the feeds evaluated. The second part of the chapter is focused on the deep solvent extraction of a spent hydrocracking catalyst to characterize the species adsorbed on the surface, with the final goal of increasing our understanding of the deactivation mechanism. The solvent extractions were carried out by conventional Soxhlet technique using dichloromethane under 1 atm of nitrogen for ~24 h. Then, the Soxhlet-extracted solid was solvent-extracted again using an accelerated solvent extraction apparatus and CH2Cl2 at 120 °C and 1500 psi of nitrogen for 1 h. The organic extracts were characterized by elemental analysis, asphaltene solubility profile, and electron spray ionization and atmospheric pressure photoionization MS. Based on the literature and the MS results, a general mechanism for the conversion of N-compounds was proposed. Basic N-species with double bond equivalence values less than 10 can be preferentially adsorbed onto the strong acid sites of the catalyst for an extended amount of time, which, along with the heavy polynuclear aromatics, leads to coke formation and catalyst deactivation.

Currently, there is no well-established methodology to predict coke morphology in Delayed Coking from feed characteristics. We found that for a series of fourteen coking feeds from different parts of the world, coke morphology and shot-coke propensity can be predicted by determining the asphaltene solubility parameter using the asphaltene solubility profile method without further separation and in similar to 25 min runs. The results are attributed to asphaltenes with higher solubility parameters that favor phase separation from the hydrocarbon matrix and lead to shot coke formation. Similarly, asphaltene peptizability measured by flocculation onset, Delta PS stability parameter determined by asphaltene solubility profile, and surface area measurements of MCRT cokes showed good potential for predicting coke morphology and shot-coke tendency of coking feeds. Conversely, mean particle size measured by cross-polarized light optical microscopy of the MCRT cokes showed a relatively large dispersion of the data and a weak correlation with the shot-coke propensity. Finally, a general scheme for the formation of shot and sponge cokes during Delayed Coking was proposed.