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In the alkaline system, the iron complex was used to absorb hydrogen sulfide to obtain sulfur, and the iron complex absorbent was oxidized and regenerated at the anode by electrolysis method for recycling, and hydrogen was obtained at the cathode. This process can recover both hydrogen and sulfur from hydrogen sulfide and avoid the harsh conditions of strong acidity. In this paper, SPE electrode is used in the oxidation and regeneration process of iron complex. The results show that the oxidation current density of iron complex at SPE electrodes are one order of magnitude higher than that of traditional electrodes, and the current efficiency is slightly lower than that of traditional electrode. The current efficiency of carbon cloth SPE electrode reaches 90% from 0.25 to 0.5V, the performance of complexed iron oxidation is better than that of the stainless-steel mesh SPE electrode, and the side reaction is mainly EDTA oxidation reaction.

High-resolution mass spectrometry enables molecular characterization of heavy petroleum fractions for petroleomics research. However, results from mass spectrometry are usually not quantitative. Th...

A high-sulfur (4.69 wt%) crude oil was discovered in the China Bohai Bay Basin which is known to contain low sulfur crude oil. The composition of this high sulfur crude oil and its geological origin are unknown. In this study, thiophenic and sulfidic sulfur compounds were isolated from the crude oil by methylation/demethylation and characterized using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography-mass spectrometry (GC–MS). Relatively high abundance of sulfur compounds with 30 carbon atoms and 5–7 double bond equivalence (DBE), which were assigned to sulfurated steranes with thiophene or tetrahydrothiophene moieties. Some of these compounds have not been reported in fossil fuels. In addition to commonly found sulfur compounds in petroleum feedstock, such as benzothiophenes and dibenzothiophenes, other structural sulfur compound types were detected: long-chain 2,5-di-n-alkylthiolanes, 2,5-di-n-alkylthianes, bicyclic terpenoid sulfides, isoprenoid thiophenes, and isoprenoid benzothiophenes. The presence of abundant biomarker sulfur compounds suggests that the sulfuration of the high sulfur crude oil was occurred in the early diagenesis stage instead of a thermochemical sulphate reduction (TSR) process.

Ruthenium-ion-catalyzed oxidation (RICO) is an approach for investigating the structure of heavy oils by selectively removing aromatic carbon from petroleum fractions, while leaving the structural ...

Recovery hydrogen from hydrogen sulfide is an effective way of utilizing exhaust gas. In this paper, removal of hydrogen sulfide by indirect electrochemical process was studied using acidic aqueous solution of Fe3+/Fe2+ as the electrochemical intermediate. Solid polymer electrolyte was applied to hydrogen production by indirect electrolysis of H2S, in which the anode was graphite cloth, the cathode was the platinized graphite cloth, and the membrane was proton exchange membrane. The results of electrolysis experiments showed the relationship of current density as a function of electrolytic voltage at constant flow rate of electrolyte, temperature, and electrolyte composition. The effect of the cathode liquid velocity on current density was small. When the flow rate of anode electrolyte was greater than 200 L/hr., the current density tended to be stable. When [Fe3+]>0.20 mol/L, the concentrations of Fe2+ and Fe3+ ions in the anode solution had no significant impact on the current density. The current density gradually increased with temperature. In the electrolytic process of hydrogen production, the Fe2+ ions diffused from the anode to the cathode. The amount of diffusing Fe2+ ions gradually increased with time. The effect of Fe2+ ions diffusion from anode to cathode on hydrogen production was discussed.

Forecasting of the gasoline demand is a key issue for refineries in China. Some international energy organizations (IEOs) and international oil companies have estimated the gasoline demand in China for the next 20 years. These organizations and companies used the assumptions that the technology of clean-energy vehicles do not gain significant progresses, and they do not consider the trends of policy changes of different provinces in China. So the forecast of IEOs (international energy organizations) may not reflect the real trend of gasoline demand in China. In this paper, we considered more stringent regional environmental regulations and the possibility of technological progress in clean-energy vehicles, using the bottom to up method to estimate the gasoline demand of all 30 provinces in China, adding them up, to gain the forecast of total gasoline demand in China for the next twenty years. The result shows that gasoline demand will increase slower and decrease faster than the estimation of some mean IEOs (international energy organizations).

Highly active Zn–Al composite oxides were synthesized via a hydrothermal process followed by thermal treatment and were used as supports to prepare Ni-based hydrogenation catalysts for catalytic deoxygenation of oleic acid, stearic acid, and 1-octadecanol. The results showed that increasing the temperature of hydrothermal synthesis changed the morphology of the Zn–Al composite oxides from sheet-like structures to spheroidal structures. High hydrothermal synthesis temperatures enhanced the interaction between Zn and Al atoms, resulting in more ZnAl2O4 spinel phase. This phase not only improved the chemical stability of the support but also supplied strong basic sites which efficiently inhibited the formation of by-products and increased the yield of heptadecane in the catalytic deoxygenation of oleic acid. Stearic acid and 1-octadecanol could be readily transformed to alkanes in the presence of metallic Ni and ZnAl2O4 phase. Decarbonylation of the octadecanal intermediate and dehydrogenation of 1-octadecanol were key reaction pathways to produce heptadecane, in which decarbonylation was catalyzed by metallic Ni, while the dehydrogenation was attributed to synergistic catalysis between metallic Ni and the strong basic sites of the support. Individual metallic Ni only catalyzed the cleavage of C–H bonds but did not affect the O–H bond of 1-octadecanol.

Electrochemical reduction desulfurization is a low cost, environmental friendly technology which is capable of achieving a high degree of automation. Electrochemical coupling reactions of organic sulfur hydrogenation and water electrolysis on the C/Nafion electrodes were performed. The electrochemical desulfurization was determined by cyclic voltammetry (CV), bulk electrolysis with coulometry (BEC) and electrochemical impedance spectroscopy (EIS) techniques. Thiophene and benzyl mercaptan were used as model organic sulfur compounds. The results of cyclic voltammetry showed that the electrochemical hydrogenation reduction reaction of thiophene occurred at about −0.35 V. The process included proceeding chemical reaction and electrochemical reaction. The currents generated from thiophene hydrogenation reactions increased with the reaction temperature and the H + concentration of the electrolyte acidity of anode. Under the same reaction conditions, the desulfurization efficiency of benzyl mercaptan was significantly higher than that of thiophene. From the products of electrolytic reactions, the mechanisms of electrochemical hydrogenation of thiophene were proposed, consisting of two pathways: ring opening followed by hydrogenation and directly hydrogenation followed by ring opening. The proposed reaction mechanisms were consistent with the EIS results, indicating the predominant reactions were ring opening followed by hydrogenation. The reaction products and EIS results suggested that the reaction mechanisms of electrochemical hydrogenation of benzyl mercaptan were by breaking C S bond to form H 2 S and toluene.

Sulfur compounds in deep hydrodesulfurization (HDS)-derived diesels were effectively separated into thiophenic and sulfidic fractions using the methylation/demethylation method and characterized by gas chromatography–mass spectrometry (GC–MS) and GC–sulfur chemiluminescence detector (SCD). Sulfidic fractions account for over 15 wt % of total residual sulfur, in which a series of refractory cyclic sulfidic compounds, 1,1-dimethylhexahydrodibenzothiophenes (1,1-DMH6DBTs) and 1,9b-dimethylhexahydrodibenzothiophenes (1,9b-DMH6DBTs), were found in the diesels, and larger molecular weight homologues were identified. Some homologue series of C1–C4 alkyl-substituted thiaadamantanes were detected in the HDS diesel. These cyclic sulfidic components are refractory to deep HDS, which require more prudent catalysis and reaction systems to achieve ultralow-sulfur diesel (ULSD) production.

Delayed coking is an important petroleum resid conversion process. The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids. Eight commercial delayed coking liquids were characterized by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatographic techniques. High relatively abundant heteroatom compounds in the coking liquids were 1–4 aromatic-ring pyridinic nitrogen compounds, carbazoles, benzocarbazoles, phenols, mercaptans, benzothiophenes, dibenzothiophenes, and naphthobenzothiophenes. Coking liquids derived from various feeds had similar compound class types, molecular weight distribution ranges, and double bond equivalents (DBE). However, the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied. A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking process. The results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.

Catalytic deoxygenation of fatty acids to alkanes is an ideal route to produce biodiesel with high heating value. However, traditional transition-metal sulfide and noble metal catalysts are sulfide-contaminated, high cost, or easily poisoned. To overcome the above issues, this work developed a non-noble and sulfide-free reduced transition-metal composite NixNbyOz, which was effective to selectively hydrogenate stearic acid, a typical fatty acid model compound, to diesel-range alkanes. By using a simple slurry method, reduced NixNbyOz catalysts have been successfully prepared with an outstanding catalytic performance. The results showed that catalyst Ni0.5Nb0.5Oz effectively converted stearic acid to n-alkanes with nearly 100% conversion and >99% n-alkanes selectivity at mild conditions (513 K and 3.5 MPa of H2 pressure). Appropriate Nb species improved the dispersion of Ni species, which may supply more hydrogenation active sites. Two possible reaction routes of stearic acid were proposed, and the hydrogenolysis of stearyl stearate was confirmed as the rate-determining step based on the kinetics experiments. Because of moderate acidity of Nb species, the ratio of C17/C18 alkane was not markedly affected by reaction conditions when the conversion of stearic acid was higher than 99%. Moreover, catalyst Ni0.5Nb0.5Oz showed a high recycle ability and compatibility for other long-chain fatty acids, demonstrating that catalyst Ni0.5Nb0.5Oz is a promising green catalyst for producing biodiesel from fatty acids.

Delayed coking is a common resid conversion process used in refining operations. A large amount of oil-containing wastewater is produced during the hydraulic decoking process. The coking wastewater contains emulsions which are difficult to process in water treatment plants, especially when the coker is fed with feedstocks have high content of heteroatoms. This study examined the molecular composition of emulsified oil and dissolved organic matter (DOM) in coking wastewater. The emulsification agents in coking wastewater were identified. The emulsified oil and DOM were separated and enriched by liquid–liquid extraction, solid phase extraction, and adsorption chromatography, and then characterized by gas chromatography-mass spectrometry and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry analyses. The results showed that the emulsified oil and DOM in coking wastewater contained highly condensed molecules with a large number of nitrogen and oxygen heteroatomic compounds. The OxSy surfactants and their derivatives, polyoxyethylene ether, and the strong polar oxygen-, nitrogen-, and sulfur-containing compounds are likely the oil–water emulsification agents.

Co-Mo sulfide catalysts with different particle size and structures were prepared in ethanol-water mixed solvent followed by a low-temperature sulfurization process, and were tested in dibenzothiophene hydrodesulfurization. The effects of the ethanol/water ratio on the particle size of precursors, active phase composition, active site number, morphology, and hydrodesulfurization activity of the final catalysts were investigated. The atomic ratio of Co/Mo and active phase morphology of catalysts closely relate to the dielectric constant of ethanol-water mixed solvent. Appropriate dielectric constant favors the formation of (Co)MoS2 slabs with shorter length (∼ 5.0 nm) and higher stacking number (∼ 4.3 layers), resulting in more coordinatively unsaturated sites, especially in the corner sites. The catalytic activity not only depends on the active sites of CoMoS phase, but also on that of Co9S8 and MoS2 phases because of synergistic effect. For MoS2 and CoMoS phases, the corner sites show higher direct desulfurization activity than the edge sites.

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 relative...

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.

Although the progress of high resolution mass spectrometry in the past decade has enabled the molecular characterization of dissolved organic matter (DOM) in water as a whole, fractionation of DOM is necessary for a comprehensive characterization due to its super-complex nature. Here we proposed a method for the fractionation of DOM in a wastewater based on solubility and acidic-basic properties. Solid phase extraction (SPE) cartridges with reversed phase retention and ion-exchange adsorption capacities, namely MAX and MCX, were used in succession to fractionate a petroleum refinery wastewater into four fractions: hydrophobic acid (HOA), hydrophobic neutral (HON), hydrophobic base (HOB), and hydrophilic substance (HIS) fractions. According to the total organic carbon (TOC) analysis, 72.6% (in term of TOC) of DOM was extracted in hydrophobic fractions, in which HON was the most abundant. Hydrophobic extracts were characterized by negative and positive ion electrospray (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), respectively. Compounds with multiple oxygen atoms were predominant in the HOA, which were responded strongly in the negative ESI MS. Nitrogen containing compounds were the major detected species by positive ion ESI in all hydrophobic fractions. The molecular composition of the DOM were discussed based on the FT-ICR MS results. The fractionation provided salt free samples which enables the direct analysis of the fractions by ESI and a deep insight into the molecular composition of DOM in the wastewater. The method is potential for routine evaluation of DOM in industry wastewaters, as well as environmental water samples.

Ruthenium ion-catalyzed oxidation (RICO) is an oxidative degradation approach for the structural investigation of petroleum fractions. It is based on the selective oxidation and near quantitative removal of aromatic carbon from aromatic petroleum fractions, while leaving the structural integrity of aliphatic units intact. RICO method has played a highly useful role in the investigation of the molecular structures of heavy petroleum. It distinguishes alkyl groups attached to aromatic rings, alkyl bridges between aromatic rings, the nature of aromatic condensation, etc. The application of RICO to petroleum chemistry was promoted by Strausz and coworkers for the study of asphaltene and other high molecular weight petroleum fractions. Structural details on asphaltenes and their ramifications were revealed by the RICO-based studies, and a hypothetical molecular model was proposed for the petroleum asphaltenes. The structural information obtained from the model is valuable for understanding such complex molecular systems. Another application of the RICO technique in the petroleum industry is the characterization of biomarkers in heavy petroleum fractions and kerogen, which were connected to the condensed core structures by chemical bonds. Generally, only the oxidation of aromatic carbon to carbon dioxide and carbonyl functionalities in RICO is considered; however, other reactions may also take place. Since they occur parallel to the oxidation of aromatic carbon, misinterpretation of the relevant experimental results may result. Recent research based on ultrahigh-resolution mass spectrometry has provided new evidence for the side reactions, which leads to a more informative interpretation of the RICO results. This paper reviews the RICO-related studies on petroleum fractions. The interpretation of RICO experimental results is also discussed.

Electrochemical reduction desulfurization is a promising technology for petroleum refining which is environmental friendly, low cost and able to achieve a high degree of automation. Electrochemical hydrogenation of thiophene was performed in a three-electrode system which SPE electrode was the working electrode. The electrochemical desulfurization was studied by cyclic voltammetry and bulk electrolysis with coulometry (BEC) techniques. The results of cyclic voltammetry showed that the electrochemical hydrogenation reduction reaction occurred at -0.4V. The BEC results showed that the currents generated from thiophene hydrogenation reactions increased with temperature. According to Arrhenius equation, activation energy of thiophene electrolysis was calculated and lower activation energy value indicated it was diffusion controlled reaction. From the products of electrolytic reactions, the mechanisms of electrochemical hydrogenation of thiophene were proposed, consisting of two pathways: openingring followed by hydrogenation, and hydrogenation followed by ring opening.