Ratios Of Hydrocarbons Research Articles

Co3o4/?-al2o3 as a Catalyst for Green Chemicals Production via Catalytic Dehydration of Bio-ethanol

The catalytic dehydration of bio-ethanol is an effective route to transform alcohol to valuable hydrocarbons and chemicals such as olefins and aromatics. There are a variety of reactions that involve, after ethylene is formed as an intermediate, such as oligomerization, aromatization, and alkylation. Products can be, for examples, butylene, benzene, derivatives of benzene, and oxygenates. In this research, cobalt oxide-promoted alumina (Co3O4/??-Al2O3) was examined, aiming to investigate the production of high valuable oxygenate compounds and hydrocarbons in bio-ethanol dehydration. The amount of Co loading was fixed at 5.0 %. The catalysts were characterized using SAA, XRD, and XPS, and tested in a fixed-bed reactor under atmospheric pressure at 500 °C for 8 h. Additionally, the gaseous products were analyzed using an on-line GC, and the oil products were analyzed using GCxGC-MS/TOF. With oxide loading, the amount ofC9 and C + aromatics increased in the oil as ethylene decreased in the gas. The major components in the oil are oxygenate compounds, which consisted of ketones and alcohols such as 2-butanone, 2-pentanone,and phenol, together with hydrocarbons such as benzene, and a trace amount of p-xylene, ethyl-benzene, and naphthalene. The ratio of oxygenates and hydrocarbons was 19:1. Furthermore, XPS result indicated that Co3O4 mainly existed on ??-Al2O3, and after use, some of Co3O4 transformed to CoO.

Halloysite nanotubes as a stabilizer: fabrication of thermally expandable microcapsules via Pickering suspension polymerization

Core-shell thermally expandable microcapsules were prepared via Pickering suspension polymerization. Acrylonitrile (AN) and methyl methacrylate (MMA) were used as the comonomers and the halloysite nanotubes (HNTs) were used as the Pickering emulsifier. The influence of the HNT concentration, AN/MMA ratio, and types of hydrocarbon was investigated. When the HNT concentration was 0.6 wt%, the microcapsules exhibited a core-shell morphology that contained approximately 35 wt% of the blowing agents with an average particle size of 232.0 μm. Increasing the MMA contents resulted in a larger particle size and lower thermal stability. Core-shell microcapsules could be synthesized using iso-hexane, iso-octane, and n-octane, but microcapsules could not be fabricated with n-pentane. At 1 and 3 bar, the contents of the encapsulated blowing agents were 10 %, whereas the contents of the encapsulated blowing agents were approximately 35 and 60 % at 1.5 and 2 bar, respectively.

A Crossplot for Mud Logging Interpretation of Unconventional Gas Shale Reservoirs and its Application

The drilling time data of gas logging are used to calculate drilling time ratio of the reservoir, and the total hydrocarbon data are used to calculate hydrocarbon contrast coefficient and to establish the drilling time ratio--hydrocarbon contrast coefficient crossplot. The standards of distinguishing the boundaries of hydrocarbon zones, hydrocarbonaceous water layers and dry layers are determined according to the statistics of regional oil testing data. Based on the standards, the crossplot is divided into three areas: hydrocarbon zone, hydrocarbonaceous water layer and dry layer, which are used in mud logging interpretation of abnormal shows in oil and gas layers. This method is widely used for low-resistivity reservoirs, fracture reservoirs, shale gas layers, and especially in the oil and gas zone with weak show and a single component. It is more applicable and accurate than some conventional interpretation methods such as the triangle plot, PIXLER plot, dual light hydrocarbon alkyl ratio and hydrocarbons ratio (3H).

Thermal maturity, source rock potential and kinetics of hydrocarbon generation in Permian shales from the Damodar Valley basin, Eastern India

This study investigates the source rock characteristics of Permian shales from the Jharia sub-basin of Damodar Valley in Eastern India. Borehole shales from the Raniganj, Barren Measure and Barakar Formations were subjected to bulk and quantitative pyrolysis, carbon isotope measurements, mineral identification and organic petrography. The results obtained were used to predict the abundance, source and maturity of kerogen, along with kinetic parameters for its thermal breakdown into simpler hydrocarbons.The shales are characterized by a high TOC (>3.4%), mature to post-mature, heterogeneous Type II–III kerogen. Raniganj and Barren Measure shales are in mature, late oil generation stage (Rr%Raniganj = 0.99–1.22; Rr%Barren Measure = 1.1–1.41). Vitrinite is the dominant maceral in these shales. Barakar shows a post-mature kerogen in gas generation stage (Rr%Barakar = 1.11–2.0) and consist mainly of inertinite and vitrinite. The δ13Corg value of kerogen concentrate from Barren Measure shale indicates a lacustrine/marine origin (−24.6–−30.84‰ vs. VPDB) and that of Raniganj and Barakar (−22.72–−25.03‰ vs. VPDB) show the organic provenance to be continental. The δ13C ratio of thermo-labile hydrocarbons (C1–C3) in Barren Measure suggests a thermogenic source.Discrete bulk kinetic parameters indicate that Raniganj has lower activation energies (ΔE = 42–62 kcal/mol) compared to Barren Measure and Barakar (ΔE = 44–68 kcal/mol). Temperature for onset (10%), middle (50%) and end (90%) of kerogen transformation is least for Raniganj, followed by Barren Measure and Barakar. Mineral content is dominated by quartz (42–63%), siderite (9–15%) and clay (14–29%). Permian shales, in particular the Barren Measure, as inferred from the results of our study, demonstrate excellent properties of a potential shale gas system.

Dual Role of Hydrogen in Low Temperature Plasma Enhanced Carbon Nanotube Growth

The gas composition during carbon nanotube (CNT) growth has received much attention because it largely determines the properties of the nanotubes and the yield of the growth. Here, we investigated the influence of hydrogen to hydrocarbon ratio on the CNT growth at low temperatures (<500 °C) using plasma-enhanced chemical vapor deposition (PECVD). Hydrogen was found to have a dual role during the growth process on TiN using catalytic nickel or cobalt nanoparticles. On the one hand, when the ratio of hydrogen to hydrocarbon partial pressure was low, CNT growth terminated well before the total process duration. As a result, no CNT growth was observed without hydrogen added to the gas mixture. The growth process could not be prolonged or reactivated upon performing in situ reducing or oxidizing cycles. On the other hand, when [H2]/[C2Hx] was high, catalyst dependent etching of the CNT forest occurred. For nickel catalyzed CNT growth, the high relative hydrogen content resulted in etching of the CNT forest, wh...

A method for stable carbon isotope ratio and concentration measurements of ambient aromatic hydrocarbons

Abstract. A technique for compound-specific analysis of stable carbon isotope ratios and concentration of ambient volatile organic compounds (VOCs) is presented. It is based on selective VOC sampling onto adsorbent-filled cartridges by passing large volumes of air (up to 80 L) through the cartridge. The hydrocarbons are recovered by thermal desorption followed by two-step cryogenic trapping and then are separated by gas chromatography in the laboratory. Once separated, individual VOCs are subjected to online oxidation in a combustion interface and isotope ratio analysis by isotope ratio mass spectrometry. The method allows measurements of stable carbon isotope ratios of ambient aromatic VOCs present in low pptV to ppbV levels with an accuracy of typically better than 0.5 ‰. The precision of concentration measurements is better than 10%. Examples of measurements conducted as part of a joint Environment Canada–York University (EC-YU) measurement campaign at a semi-rural location demonstrate that the ability to make accurate measurements in air with low VOC mixing ratios is important to avoid bias from an overrepresentation of samples that are strongly impacted by recent emissions.

Geochemistry of Paleozoic marine petroleum from the Tarim Basin, NW China: Part 5. Effect of maturation, TSR and mixing on the occurrence and distribution of alkyldibenzothiophenes

Fifty-four oils and 20 gas condensates from the cratonic region of the Tarim Basin, NW China were quantitatively analyzed by gas chromatography–mass spectrometry to elucidate the influence of thermal maturation, multiple charges and mixing, and thermochemical sulfate reduction (TSR) on the relative distributions of alkyldibenzothiophenes (DBTs) vs alkylphenanthrenes, which are widely used to interpret depositional environment and lithology. Concentrations of DBTs relative to DBTs in the aromatic hydrocarbon fraction and ratios of dibenzothiophene/phenanthrene (DBT/P) exhibit wide variations in the studied samples. Field observations, coupled with a suite of oil sand pyrolysis experimental results, suggest that DBTs are more easily released from kerogen and/or asphaltenes and are more easily destroyed in oil than the alkylphenanthrenes. The DBT/P ratio initially increases during early maturation and then decreases in the post mature stage. Concentrations of DBTs are low in samples from the cratonic region of the Tarim Basin (most samples have DBT/P ratios<1) because of their high maturity. The unusually high concentration of DBTs in some gas condensates from the Tazhong Uplift is possibly the result of back reaction of H2S formed by TSR with hydrocarbons. A typical TSR-altered sample represented by ZS1C has a DBT/P ratio as high as 22.3 with DBTs representing 63.6% of components in the aromatic hydrocarbon fraction. Mixing of a TSR-altered late charge with previously existing oils is responsible for the wide range of variation of DBT concentrations and DBT/P ratios. The influence of TSR on DBT/P ratios is easily distinguishable from thermal maturation because the former increases the ratio while the latter decreases the ratio. Consequently, the DBT/P ratio is not valid as a parameter to interpret source rock lithology and depositional environment in the present case study.

Modern climate and vegetation variability recorded in organic compounds and carbon isotopic compositions in the Dianchi watershed

The aliphatic hydrocarbons distribution and compound-specific characteristics of carbon isotopic compositions in the sediments from the small catchment (197 km(2)) of the Dianchi watershed were investigated for identification of modern climate and vegetation variations in the study area. Results show that a regular bimodal n-alkanes distribution ranged from nC16 to nC33, with strong dominance at nC17 for short-chain n-alkanes and nC31 for long-chain n-alkanes. Mass chromatogram of total fatty acids also indicates corresponding mixed contribution of algae, hydrophilous non-emergent (C4 plants) and terrestrial plants (C3 plants) to sedimentary organic matter (OM). At the depth of -24 to -25 cm (early 1970s), nC31/nC17 and terrestrial to aquatic ratio of hydrocarbons (TAR) values decrease, suggesting a shift of OM origins from C3 terrestrial plants to algae-derived C4 plants. The highest water stage in 1971 was found to be recorded in the particle size (<4 μm). For long-chain alkanes, the values of δ (13)Corg and δ (13)Cn-alkanes varied from -26.9 to -22.4 and -33.4 to -27.9 ‰, respectively. Population growth and economic development led to a demand for abundant habitable and cultivable land. Due to unreasonable land expansion, the primordial forest sporadically distributed. A mixture of C3 and C4 plants probably replaced C3 plants as the sources of OM in the past 10 years. The changes of land-use types and severe drought resulted in the excessive OM inputs to the watershed.

Decomposition of ethane molecules at atmospheric pressure using metal assisted laser induced plasma

The decomposition of ethane (C2H6) and the subsequent conversion to other hydrocarbons are investigated using a Q-switched (Q-SW) Nd:YAG laser induced plasma inside a controlled chamber. The metal targets, including iron, copper, nickel, and palladium, are employed to assist the plasma formation and ethane decomposition. Fourier transform infrared spectroscopy and gas chromatography are used for identifying and analyzing the products to determine dissociation rates as well. Several C1 and C2 components, namely, methane (CH4), ethylene (C2H4), and acetylene (C2H2), as well as heavier C3, C4, and C5 components, such as propane, butane, and pentane, are obtained after ethane decomposition. The yield, selectivity, and conversion ratios of hydrocarbons mainly depend on the metal species as the active catalysts during laser exposure. The most abundant component is found to be ethylene having a selectivity of &#x223C;39% using a palladium target. This technique offers high reproducibility to generate selective and desired hydrocarbon compounds in the controlled chamber.

Organic geochemical and petrographic characteristics of Neogene organic-rich sediments from the onshore West Baram Delta Province, Sarawak Basin: Implications for source rocks and hydrocarbon generation potential

The Neogene succession of the onshore petroleum prolific West Baram Province of North-West Borneo contains organic-rich sediments particularly within Sarawak Basin. Bulk and quantitative pyrolysis results, coupled with organic petrographic characteristics of Neogene organic-rich sediments have enabled investigation of the source rock characteristics and evaluation of the hydrocarbon generation potential. The results were used to assess the quantity of organic matter, kerogen composition, thermal maturity and type of petroleum that could possibly be generated from these Neogene sediments.The total organic carbon (TOC) contents of the Neogene sediments range between 1.06 and 11.11 wt. % and Hydrogen Index (HI) values are largely below 105 mg HC/g TOC, suggesting that the sediments are organically rich and contain gas-prone Type III kerogen. This kerogen type is supported by the abundant terrestrial materials (i.e., vitrinite phytoclasts, spores and pollen), low atomic hydrogen-to-carbon atomic (H/C) ratio and high abundance of aromatic hydrocarbons in Pyrolysis GC pyrograms and would likely generate mainly condensate and gas. The analysed samples have vitrinite reflectance in the range of 0.39–0.48 %Ro and pyrolysis Tmax in the range of 401–434 °C which indicate that these Neogene sediments contain immature to very early-mature organic matter. This implies that these onshore sediments have not been buried to a sufficient depth, however the offshore stratigraphic equivalent of these sediments are known to have been buried to deeper depth and could therefore act as an effective petroleum source rock in particular for natural gas.

Preliminary Evaluation of Trace Hydrocarbon Speciation and Abundance as an Exploration Tool for Footwall-Style Sulfide Ores Associated with the Sudbury Igneous Complex, Ontario, Canada

Deposits of Cu-Ni-platinum group elements (PGE)–rich sulfides occur along the North Range footwall of the Sudbury Igneous Complex, Ontario, Canada. The deposits have been modified chemically, mineralogically, and texturally by multiple syn- to postmagmatic hydrothermal events and are hosted mainly within Sudbury breccia, a contact metamorphosed and hydrothermally altered impact breccia. The composition of C1 to C6 unsaturated and saturated hydrocarbons in bulk fluid inclusion volatiles in the matrix of the Sudbury breccia was investigated using in-line rock-crushing gas chromatography (GC) in order to compare the hydrocarbon composition of this rock type in breccia zones containing economic footwall sulfide deposits at the Morrison deposit (Levack mine, North Range, Sudbury, Ontario) with barren breccia zones. Trace hydrocarbons, possibly abiogenic in origin, occur throughout the Sudbury Igneous Complex footwall and country rocks investigated. However, there are differences in the composition and abundance of bulk hydrocarbons released from mineralized and barren Sudbury breccia when fluid inclusions are opened. Volatiles released from samples of Sudbury breccia from sulfide-mineralized and sulfide-barren environments showed the following: (1) higher average abundances of light saturated hydrocarbons (C1–C4) and an approximately 2× higher total abundance of hydrocarbons (mol/g of rock basis) associated with samples from the mineralized study area, and (2) comparable average unsaturated hydrocarbon abundances in both settings, but a larger range in unsaturated hydrocarbon abundances in the mineralized study area. Differences in bulk hydrocarbon abundance and composition reflect differences in the abundance and hydrocarbon content of fluid inclusions trapped in the barren and mineralized Sudbury breccia zones. In addition, the compositional modification of circulating fluids by processes and conditions unique to the mineralized Sudbury breccia environment may have occurred prior to inclusion entrapment (e.g., modification by mineral catalysts, differences in temperature and oxygen fugacity). Preliminary spatial analysis of the hydrocarbon distribution within and surrounding the Morrison deposit shows that the total hydrocarbon abundance in the Sudbury breccia does not change with orebody proximity within a single host breccia zone. However, volatiles trapped in the Sudbury breccia matrix near the top of the footwall deposit, where it is physically connected to contact-style (Ni-Cu-PGE) ores, have elevated unsaturated hydrocarbon abundances (e.g., propene) compared to other parts of the same breccia zone distal to this zone of physical connection. Samples of the PGE-enriched Sudbury breccia and mineralized veins containing alteration assemblages characteristic of the footwall ore styles have higher unsaturated hydrocarbon abundances and unsaturated/saturated ratios compared to Sudbury breccia and vein samples that are PGE poor. Localized enrichments in unsaturated hydrocarbons in Sudbury breccia zones may be the result of specific ore minerals and metal complexes (involving the PGE and group VIII metals) that acted as catalytic agents, modifying the composition of initially light saturated hydrocarbon species prior to entrapment in fluid inclusions. To apply the analysis of hydrocarbon compositions in trapped fluid inclusions to discriminating mineralized from barren zones of Sudbury breccia, samples from targeted areas were compared to samples of barren Sudbury breccia (“background”). Although a large data set is presented here to establish these compositional fields, analysis of smaller sample subsets from each environment yields a statistically significant separation between the two environments. Total hydrocarbon abundance, C3/C1 ratios, and unsaturated/saturated hydrocarbon ratios are useful indicators of sulfide ore proximity and may help delineate regions enriched in PGE.

Investigation of carbonyl compound sources at a rural site in the Yangtze River Delta region of China

Carbonyl compounds are important intermediates in atmospheric photochemistry, but their primary sources are still not understood well. In this work, carbonyls, hydrocarbons, and alkyl nitrates were continuously measured during November 2011 at a rural site in the Yangtze River Delta region of China. Mixing ratios of carbonyls and hydrocarbons showed large fluctuations during the entire measurement. The average level for total measured volatile organic compounds during the pollution episode from 25th to 27th November, 2011 was 91.6ppb, about 7 times the value for the clean period of 7th–8th, November, 2011. To preliminarily identify toluene sources at this site, the emission ratio of toluene to benzene (T/B) during the pollution episode was determined based on photochemical ages derived from the relationship of alkyl nitrates to their parent alkanes. The calculated T/B was 5.8ppb/ppb, significantly higher than the values of 0.2–1.7ppb/ppb for vehicular exhaust and other combustion sources, indicating the dominant influence of industrial emissions on ambient toluene. The contributions of industrial sources to ambient carbonyls were then calculated using a multiple linear regression fit model that used toluene and alkyl nitrates as respective tracers for industrial emission and secondary production. During the pollution episode, 18.5%, 69.0%, and 52.9% of measured formaldehyde, acetaldehyde, and acetone were considered to be attributable to industrial emissions. The emission ratios relative to toluene for formaldehyde, acetaldehyde, and acetone were determined to be 0.10, 0.20 and 0.40ppb/ppb, respectively. More research on industrial carbonyl emission characteristics is needed to understand carbonyl sources better.

Development of new method of δ13C measurement for trace hydrocarbons in natural gas using solid phase micro-extraction coupled to gas chromatography isotope ratio mass spectrometry

Compound specific isotope analysis (CSIA) of normal-level hydrocarbons (C1–C4) in natural gas is often successfully used in natural gas origin identification and classification, but little progress so far has been made for trace level hydrocarbons (C5–C14) in natural gas. In this study, we developed a method for rapid analysis of carbon isotopic ratios for trace hydrocarbons in natural gas samples. This method can be described as a combined approach characterized by solid phase micro-extraction (SPME) technique coupled to gas chromatography isotope ratio mass spectrometry (GC/IRMS). In this study, the CAR–PDMS fiber was chosen as the SPME adsorptive material after comparative experiments with other four fibers, and the parameters, including equilibration time, extraction temperature and desorption time, for efficient extraction of trace hydrocarbons were systematically optimized. The results showed the carbon isotopic fractionation was not observed as a function of equilibration time and extraction temperature. And the δ13C signatures determined by SPME-GC/IRMS were in good agreement with the known δ13C values of C5–C14 measured by GC–IRMS, and the accuracy is generally within ±0.5‰. Five natural gas samples were analyzed using this method, and the δ13C values for C5–C14 components were obtained with satisfied repeatability. The SPME-GC/IRMS approach fitted with CAR–PDMS fiber is well suited for the preconcentration of trace hydrocarbons and provides so far the most reliable carbon isotopic analysis for trace compounds in natural gas.

Investigation of the Disperse Composition of Microemulsions and the Laws Governing the Polymerisation of Styrene in Them

A study was made of the effect of cetyl alcohol on the disperse composition of microemulsions formed by diluting concentrated toluene–surfactant–water systems with water until a ratio of hydrocarbon to aqueous phase of 1:50 is reached. It was shown that the microemulsion formed is characterised by a bimodal particle size distribution. With cetyl alcohol concentrations in the toluene-surfactant-water system of 2–10 mol%, the system contains particles of 600–1000 nm size, and with a concentration of 25–28 mol% it contains particles of 6–25 nm size. The initiation of polymerisation of styrene in microemulsions leads to the formation of polystyrene latexes with a bimodal particle size distribution. No significant effect of cetyl alcohol on the molecular weight and molecular weight distribution of the polymers was observed.

INVESTIGATION OF STOICHIOMETRIC «AIR-FUEL» RATIO OF ORGANIC COMPOUNDS. PART 1. ALKANES

The article considered features of obtaining and applying the stoichiometric “air-fuel” ratio of organic hydrocarbons. The main objective of this work is to establish the regularities of the formation of the stoichiometric “air-fuel” ratio for the first 10 members of the alkane’s homologous series (methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane). Analyzed the chemical and physical properties of alkanes, which influence on the formation of the optimal fuel mixtures. Shown the dependences of the changing of the air mass which is consumed from the excess air ratio during combustion of perfectly clean fuel materials. Shown the exact mass values of the “air-fuel” ratio for the formation of stoichiometric mixtures of alkanes. Set the fact of reducing of the needed optimal air mass for the formation of flammable mixtures under increasing of the homologous difference of alkanes. The results of investigation can be used for regulation the combustion regimes in the internal combustion engines of a car, furnaces boilers and household appliance worked on gaseous and liquid hydrocarbons (alkanes).

Catalytic properties of CoMo/Al2O3 sulfide catalysts in the hydrorefining of straight-run diesel fraction mixed with rapeseed oil

CoMo/Al2O3 sulfide catalysts varying in preparation method and Co/Mo ratio have been tested in the hydrorefining of a mixture of straight-run diesel fraction and rapeseed oil in a flow reactor at a temperature of 340–360°C, a hydrogen pressure of 4.0–7.0 MPa, and a liquid hourly space velocity of 1–2 h−1. A comparison between catalysts prepared using citric acid (CoMo/Al2O3-1.5) and both citric and orthophosphoric acids (CoMoP/Al2O3-1.5) as promoters, with Co/Mo = 0.3 and 0.5, has demonstrated that the most active catalyst in hydrodesulfurization and hydrodenitrogenation is the phosphorus-containing Co/Mo ≈ 0.5 sample. The addition of rapeseed oil to straight-run diesel fraction lowers the hydrodesulfurization and hydrodenitrogenation activities of the CoMo sulfide catalysts, irrespective of the method by which they were prepared. The fatty acid triglyceride conversion selectivity of these catalysts depends on the Co/Mo ratio and on reaction conditions: decreasing the Co/Mo ratio from 0.46 to 0.26, lowering the reaction temperature, and raising the hydrogen pressure and hydrogen-to-feedstock ratio increase the C18/C17 hydrocarbon ratio in the hydrogenated product. The addition of rapeseed oil improves the quality of the product; however, for attaining the preset residual sulfur level in this case, the process needs to be conducted at a higher temperature than the hydrorefining of straight-run diesel fraction containing no admixture.

Use of stable isotopes to identify sources of methane in Appalachian Basin shallow groundwaters: a review.

Development of unconventional shale gas reservoirs in the Appalachian Basin has raised questions regarding the potential for these activities to affect shallow groundwater resources. Geochemical indicators, such as stable carbon and hydrogen isotopes of methane, stable carbon isotopes of ethane, and hydrocarbon ratios, have been used to evaluate methane sources however their utility is complicated by influences from multiple physical (e.g., mixing) and geochemical (e.g., redox) processes. Baseline sampling of shallow aquifers prior to development, and measurement of additional geochemical indicators within samples from across the Appalachian Basin, may aid in identifying natural causes for dissolved methane in shallow groundwater versus development-induced pathways.

Effect of zeolite on the activity of Ru/MnCO3 catalysts for Fischer–Tropsch reaction

The zeolite-containing Ru/MnCO3 3Ru(NO)-Mn catalysts were investigated on the Fischer–Tropsch synthesis (FTS) in a low pressure fixed-bed reactor. The catalytic activity and i/n ratio of C4 hydrocarbons were found to be a little higher than those of non-zeolite systems such as 3Ru(NO)-Mn alone and 3Ru(NO)-Mn with MnCO3 as a diluents, while the α-value and olefin/paraffin ratio of C2–C4 hydrocarbons were lower for the zeolite system than those of non-zeolite. The hydrocarbon cracking ability could be improved for all-in-one type Ru-Z-B as well as 3Ru(NO)-Mn physically mixed with zeolite, compared with 3Ru(NO)-Mn with MnCO3. In fact, the Ru-Z-B catalyst gives a narrower carbon distribution than the 3Ru(NO)-Mn with MnCO3 catalyst. The Ru crystallite sizes of used catalysts after 120h- and 720h-reaction were close to those of fresh catalysts, indicating no aggregation occurred. The origin of catalyst deactivation could depend on the extent of hydrocarbon deposition, even in zeolite-containing catalyst systems. The longer reaction time, the more condensed wax materials were formed and, even after a gentle calcination of the used Ru-Z-B catalyst at 350°C, the inorganic-like carbons still remain, as ascertained by TPR-Q-mass analysis. The proposed deactivation mechanism would be consistent with other analytical evidences such as thermogravimetric analysis (TGA), CO adsorption, transmission electron micrograph (TEM) of used catalysts as well as NH3-TPD of the used zeolites.

High Resolution Forensic Analysis Of Surface Sheens Helps Pinpoint Source Of Oil Leakage From The Deepwater Horizon

Alkenes commonly found in synthetic drilling-fluids were used to identify sources of oil sheens that were first observed in September 2012 close to the Deepwater Horizon (DWH) disaster site more than two years after the Macondo MC-252 well was sealed. Exploration of the sea floor by BP confirmed that the well was capped and sound. BP scientists and engineers identified the likely source as leakage from an 80-ton cofferdam abandoned during a failed attempt to control the Macondo well in May 2010. We acquired and analyzed sheen samples at the sea-surface above the Deepwater Horizon wreckage as well as oil collected directly from the cofferdam using comprehensive two-dimensional gas chromatography (GC×GC). This allowed the identification of drilling-fluid C16- to C18-alkenes in sheen samples that were absent in cofferdam oil. Furthermore, the spatial pattern of evaporative losses of sheen oil alkanes indicated that oil surfaced closer to the Deepwater Horizon wreckage than the abandoned cofferdam site. Lastly, ratios of alkenes and petroleum hydrocarbons pointed to a common source of oil found in both sheen samples and recovered from oil-coated Deepwater Horizon riser pipe buoyancy compensator module debris collected shortly after the explosion. These lines of evidence suggest that the observed sheens do not originate from the Macondo well, cofferdam, or from natural seeps. Rather, the likely source is oil trapped in tanks and pits on the Deepwater Horizon wreckage, representing a finite oil leakage volume.

Migration of PAHs in food industry sludge to the air during removal by UV and TiO2

This study was conducted to investigate the evaporation ratios of polycyclic aromatic hydrocarbons (PAHs) from the food industry treatment sludge. Five PAH compounds having different ring numbers were targeted. The effects of temperature, UV and TiO2 on PAH evaporation were also studied. All applications were performed in a specially designed apparatus. The air in the apparatus was vacuumed to collect the evaporated PAHs on the PUF cartridges. Then, these PUF cartridges were extracted for determination of PAHs. The PAH concentrations were measured by a gas-chromatography mass-spectrometer (GC–MS). 91% of the initial ∑5 PAHs in the sludge was evaporated into the air at the end of the UV application. However, this value decreased to 21% when UV was not employed. Initial and final PAH levels in the sludge were measured to determine the removed PAHs which refer to the addition of degraded and evaporated PAHs. The results indicated that the UV–TiO2 application at high temperatures was considered an appropriate PAH removal method because it restricted the evaporation of PAHs while it removed high levels of PAHs. PAHs were mainly removed from the sludge by degradation rather than evaporation with this application.