Pattern Recognition Technology Application in Intelligent Processing of Heavy Oil

Reliable and efficient product yield estimation for unknown oils after the fluid catalytic cracking (FCC) reaction is one of the key components in heavy oil intelligent processing. This paper describes the use of two chemometric pattern recognition methods, <i>k</i>-nearest neighbor (<i>k</i>-NN) classification and supervised self-organizing maps (SSOMs), for building classification models to determine the most similar oil sample to an unknown sample in a given data set and to use the FCC yields record of the correspondent oil as the product yield prediction for the unknown sample under the same reaction conditions. Two-sided <i>t</i> test, correlation analysis, and hierarchical cluster heat map analysis were performed to assess the quality of the models. The work provides laboratory evidence that <i>k</i>-NN or SSOMs techniques could all be employed for FCC product yield estimation, while the <i>k</i>-NN model would be more suitable for industrial application in terms of stability and efficiency

Molecular Characterization of Dissolved Organic Matter and Its Subfractions in Refinery Process Water by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Dissolved organic matter (DOM) in oil refinery process water was fractionated by XAD-8 resin techniques into four subfractions: hydrophobic acid (HOA), hydrophobic base (HOB), hydrophobic neutral (HON), and hydrophilic substance (HIS) fractions. Negative and positive electrospray ion (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize the composition of DOM and its subfractions. Compounds with multi-oxygen atoms were found to be predominant in DOM by either negative or positive ESI analysis, which are similar in composition to most other treated water samples. The DOM in the HOA fraction had a similar molecular composition to that of raw process water by negative ESI analysis. The DOM in the HOB fraction had a low molecular weight (MW) when analyzed by positive ESI, and basic nitrogen compounds, such as N₁ class species, were found to be predominant. The DOM in the HON fraction was predominantly O₂ class species. The DOM in the HIS fraction had a relatively wide MW distribution. All of the compounds of DOM in the HIS fraction exhibited low double bond equivalents (DBE) and low carbon numbers. The results showed that the use of the XAD-8 resin fractionation technique is valuable for characterizing trace quantities of DOM components in process water because their spectral peaks would otherwise be obscured by other abundant peaks. The origin and determination of chlorine-containing compounds, which are abundant in the negative ESI mass spectra of HOB, were discussed

Potential of Using Coal Tar as a Quenching Agent for Coal Gasification

To reduce water usage and wastewater treatment in coal gasification processing, the use of non-aqueous quenching agents was proposed. The purpose of this study is to assess the potential of using coal tar as a quenching agent for the Luger coal gasification. A low-temperature gasification-derived coal tar and an ethylene tar obtained from the petroleum naphtha cracking process in ethylene production were subjected to thermal aging tests to determine the effect of thermal severity on their viscosity and chemical composition. The viscosities of coal tar and ethylene tar as a function of the aging time were similar and relatively constant at 200 °C. At 250 °C, the coal tar was more unstable and had a shorter viscosity increase onset time than the ethylene tar. The tar samples before and after thermal aging tests were subjected to gas chromatography–mass spectrometry (GC–MS) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to determine the molecular composition. The results indicated that olefins, especially aromatic olefins in the coal tar, were unstable, which likely caused polymerization of coal tar species during thermal aging and resulted in a short viscosity increase onset time. By adding a polymerization inhibitor, the viscosity increase onset time of coal tar was prolonged. The coal tar is potential for use as a quenching agent for coal gasification

Understanding the Interfacial and Self-Assembly Behavior of Multiblock Copolymers for Developing Compatibilizers toward Mechanical Recycling of Polymer Blends

Multiblock copolymers (MBCPs) constitute a class of materials with distinctive structures and properties. Among MBCPs, linear and grafted multiblock copolymers emerge as two promising candidates for advancing the development of high-performance compatibilizers for homopolymer mixtures. However, elucidation of the underlying mechanisms for modulating their behaviors as compatibilizers remains an unresolved challenge. Here, we conducted extensive dissipative particle dynamics (DPD) simulations to study the compatibilization efficiency and micelle formation of linear and grafted multiblock copolymers in terms of the interfacial tension and self-assembly behavior. The compatibilization efficiency of all MBCPs increases with the interfacial areal concentration before reaching a plateau by reducing the unfavorable contact between homopolymers. The effect of the number of blocks of copolymers on the compatibilization efficiency is more dominant in the highly incompatible system with a high value of interfacial areal concentration. We find that there is a minimal disparity in the compatibilization efficiency between the graft and linear copolymers for weakly incompatible systems, whereas the difference is more notable for highly incompatible systems. The graft copolymer with the highest number of blocks exhibits the best compatibilization efficiency among all copolymers for highly incompatible systems. Moreover, micelle formation is a common phenomenon after the addition of copolymers due to the self-assembly behavior. We find that graft copolymers exhibit a lower tendency to form micelles compared with linear copolymers. Furthermore, we find that the micelle size of linear copolymers is larger than that of graft copolymers, suggesting a higher possibility of a copolymer phase in the homopolymer blend. Our results demonstrate how linear and graft multiblock copolymers are likely to function as compatibilizers, forming micelles due to the self-assembly behavior in the homopolymer phase as well as accumulation in the interface to reduce the interfacial tension. We anticipate that our work will be a starting point for more sophisticated in silico models of compatibilizers on the upcycling of waste thermoplastics

Compositional Changes during Hydrodeoxygenation of Biomass Pyrolysis Oil

Hydrodeoxygenation (HDO) is usually considered as a promising process for upgrading biomass pyrolysis oil (PO) to bio-fuels. However, cognition of HDO is inhibited by the complexity of the PO and upgraded products. In this study, a PO and its upgraded pyrolysis oil (UPO) samples were analyzed by nuclear magnetic resonance, gas chromatography/mass spectrometry, and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). ESI FT-ICR MS revealed the most abundant compounds in PO were O₂–O₁₈ species with double bond equivalent (DBE) values of 0–22. After HDO, oxygen numbers gradually shifted to a range of O₁–O₁₀, and DBE number also progressively decreased. The major oxygen compounds such as carbonyls, carboxylic acids, ethers, carbohydrates, and alcohols were significantly changed with respect to relative content and molecular composition. Lignin polymers were depolymerized after reduction of the carbonyl and methoxy groups. For HDO, hydrogenation of carbonyls, carbohydrates, and furans occurred under 150 °C. Dehydration, hydrodeoxygenation, and dehydration–hydrogenation reactions were initiated at 210 °C. Decarboxylation and decarbonylation required higher temperatures (>300 °C)

Quantitative Structure–Property Relationship Model for Hydrocarbon Liquid Viscosity Prediction

The liquid viscosity of hydrocarbon compounds is essential in the chemical engineering process design and optimization. In this paper, we developed a quantitative structure–property relationship (QSPR) model to predict the hydrocarbon viscosity at different temperatures from the chemical structure. We collected viscosity data at different temperatures of 261 hydrocarbon compounds (C₃–C₆₄), covering <i>n</i>-paraffins, isoparaffins, olefins, alkynes, monocyclic and polycyclic cycloalkanes, and aromatics. We regressed the experimental data using an improved Andrade equation at first. Hydrocarbon viscosity versus temperature curves were characterized by only two parameters (named <i>B</i> and <i>T</i>₀). The QSPR model was then built to capture the complex dependence of the Andrade equation parameters upon the chemical structures. A total of 36 key chemical features (including 15 basic groups, 20 united groups, and molecular weights) were manually selected through the trial-and-error process. An artificial neural network was trained to correlate the Andrade model parameters to the selected chemical features. The average relative errors for <i>B</i> and <i>T</i>₀ predictions are 2.87 and 1.05%, respectively. The viscosity versus temperature profile was calculated from the predicted Andrade model parameters, reaching the mean absolute error at a value of 0.10 mPa s. We also proved that the established QSPR model can describe the viscosity versus temperature profile of different isomers, such as isoparaffins, with different branch degrees and aromatic hydrocarbons with different substituent positions. At last, we applied the QSPR model to predict gasoline and diesel viscosities based on the measured molecular composition. A good agreement was observed between predicted and experimental data (absolute mean deviation equals 0.21 mPa s), demonstrating that it has capacity to calculate viscosity of hydrocarbon mixtures

Molecular Composition of Soxhlet <i>N</i>‑Methyl-2-pyrrolidinone Extracts from a Lignite

<i>N</i>-Methyl-2-pyrrolidinone (NMP) is a capable solvent which could extract more substance from coals than any other solvents. However, the molecular composition of the extract was still unclear. In this study, a lignite was subjected to Soxhlet extraction using pyridine followed by NMP. The NMP extract and its hydrolyzed product were characterized by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The results showed that the NMP extract and its hydrolyzed product had very high nitrogen contents and N_<i>x</i>O_<i>y</i> class species with multiple nitrogen and oxygen atoms dominant in the detected species. Relative abundance of ¹⁵N isotope and the molecular composition of extracts obtained from different extraction conditions indicated that the NMP involved into the extracts. Both self-polymerization of NMP and chemical reactions between NMP and coals occurred in the thermal extraction

Approach for Selective Separation of Thiophenic and Sulfidic Sulfur Compounds from Petroleum by Methylation/Demethylation

Detailed characterization of petroleum derived sulfur compounds has been challenging, due to the complex composition of the hydrocarbon matrix. A novel method was developed for selective separation of thiophenic and sulfidic compounds from petroleum. Sulfur compounds were methylated to sulfonium salts by AgBF₄ and CH₃I, then the polar salts were separated by precipitation from petroleum matrix. The thiophenic and sulfidic sulfonium salts were sequentially demethylated with 7-azaindole and 4-dimethylaminopyridine, obtaining original thiophenic and sulfidic compounds, respectively. The method was validated by model compounds, and applied to a diesel and a vacuum distillation petroleum fraction. Sulfur fractions were characterized by gas chromatography (GC) coupled with a sulfur chemiluminescence detector (SCD) and quadrupole mass spectrometry (MS), and high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The technique was effective to selectively obtain high-purity thiophenic and sulfidic compounds and showed rare discrimination among sulfur compounds with ranging molecular weights and degrees of unsaturation. The method would facilitate multifaceted detailed characterization of sulfur compounds in an organic complex matrix

Distribution of Acids and Neutral Nitrogen Compounds in a Chinese Crude Oil and Its Fractions: Characterized by Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

A Chinese crude oil was distilled into multiple narrow boiling fractions. The crude oil, 39 narrow distillate fractions (up to 560 °C), and atmospheric and vacuum residues were analyzed using negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The heteroatoms, N₁, N₂, N₁O₁, N₁O₂, O₁, and O₂ class species, were identified and characterized by double-bond equivalent (DBE) values and carbon numbers. The composition of crude oil was correlated with increased boiling point. Most abundant O₁ and O₂ class species had DBE values and carbon numbers corresponding to biological skeleton structures, such as hopanoic acid, secohopanoic acid, and sterol. The distribution of acids and neutral nitrogen compounds in the various fractions were determined. At higher carbon numbers, the amount of the compounds and DBE values increased gradually with the boiling point for most oil fractions. The abundant N₁ class species were centered at DBE values of 9, 12, 15, and 18. These were likely pyrrolic compounds with various numbers of aromatic rings. Species such as hopanoic acids and secohopanoic acids were highly abundant in fractions above 500 °C. Sterol-like compounds were enriched in the 460−500 °C fractions. These are likely the major species causing a high total acid number (TAN) in the crude oil

Theoretical Investigation of Water Gas Shift Reaction Catalyzed by Iron Group Carbonyl Complexes M(CO)₅ (M = Fe, Ru, Os)

We have investigated the mechanism of M­(CO)₅ (M = Fe, Ru, Os) catalyzed water gas shift reaction (WGSR) by using density functional theory and ab initio calculations. Our calculation results indicate that the whole reaction cycle consists of six steps: <b>1</b> → <b>2</b> → <b>3</b> → <b>4</b> → <b>5</b> → <b>6</b> → <b>2</b>. In this stepwise mechanism the metals Fe, Ru, and Os behave generally in a similar way. However, crucial differences appear in steps <b>3</b> → <b>4</b> → <b>5</b> which involve dihydride M­(H)₂(CO)₃COOH^– (<b>4′</b>) and/or dihydrogen complex MH₂(CO)₃COOH^– (<b>4</b>). The stability of the dihydrogen complexes becomes weaker down the iron group. The dihydrogen complex <b>4_Fe</b> is only 11.1 kJ/mol less stable than its dihydride <b>4′_Fe</b> at the B3LYP/II­(f)++//B3LYP/II­(f) level. Due to very low energy barrier it is very easy to realize the transform from <b>4_Fe</b> to <b>4′_Fe</b> and vice versa, and thus for Fe there is no substantial difference to differentiate <b>4</b> and <b>4′</b> for the reaction cycle. The most possible key intermediate <b>4′_Ru</b> is 38.2 kJ/mol more stable than <b>4_Ru</b>. However, the barrier for the conversion <b>3_Ru</b> → <b>4′_Ru</b> is 23.8 kJ/mol higher than that for <b>3_Ru</b> → <b>4_Ru</b>. Additionally, <b>4′_Ru</b> has to go through <b>4_Ru</b> to complete dehydrogenation <b>4′_Ru</b> → <b>5_Ru</b>. The concerted mechanism <b>4′_Ru</b> → <b>6_Ru</b>, in which the CO group attacks ruthenium while H₂ dissociates, can be excluded. In contrast to Fe and Ru, the dihydrogen complex of Os is too unstable to exist at the level of theory. Moreover, we predict Fe and Ru species are more favorable than Os species for the WGSR, because the energy barriers for the <b>4</b> → <b>5</b> processes of Fe and Ru are only 38.9 and 16.2 kJ/mol, respectively, whereas 140.5 kJ/mol is calculated for the conversion <b>4′</b> → <b>5</b> of Os, which is significantly higher. In general, the calculations are in good agreement with available experimental data. We hope that our work will be beneficial to the development and design of the WGSR catalyst with high performance