Catalytic upgrading of liquid hydrocarbons derived from coprocessing of heavy oil and coal

Coprocessing of heavy oil and coal under elevated temperature, hydrogen pressure and low space velocity resulted in a product slurry from which the fraction distilling below 430° C was catalytically upgraded over a commercial NiMo/Al₂O₃ catalyst in a flow reactor. At 400° C, 13.3 MPa (H₂) and LHSV of 1.0 h^?1 over 90% of sulfur and nitrogen could be removed, aromaticity reduced to 16% from 26% and the API gravity increased to 36.9 from 23.8. Hydrogen consumption under these conditions was considerably lower than that obtained for upgrading the oil sands coker gas oil. Activation energies for hydrodesulfurization and hydrodenitrogenation reactions were determined to be 59.5 and 120.4 kJ/mol, respectively.     

Thermal and flow properties of oils from salmon heads

Thermal and flow properties of unrefined oils from the heads of red or pink salmon were evaluated. Major thermal degradation of the salmon oils occurred between 200 and 450°C. Red and pink salmon oils were completely decomposed at 533 and 668°C, respectively. The phase transition of salmon oils occurred over a wide range of temperatures. The melting points of −69.6 to −0.36°C and −64.7 to 20.8°C were observed for red and pink salmon oils, respectively. The enthalpy was 40 j/g for red salmon oil and 39 j/g for pink salmon oil. Specific heat capacity ranges of 0.8 to 1.6 and 1.3 to 2.3 j/g/°C were observed for red and pink salmon oils, respectively. Both salmon oils exhibited Newtonian flow behavior. Red salmon oil required higher magnitudes of energy (kj·mol⁻¹) to flow than pink salmon oil. The viscosity of salmon oils was temperature-dependent and could be predicted by the Arrhenius equation.     

Chemical nature of coal hydrogenation oils part 2. The effect of temperature

Hydrogenation of the same coal was carried out at 400, 450, 500, 550, 600, 650 and 700°C. ¹H-n.m.r. spectra of the oils (hexane soluble portion) showed an increase in the percentage of aromatic protons and a decrease in the percentage of aliphatic protons as the temperature increases, while the percentage of benzylic protons remained constant. The aromaticity of the oils as calculated by the Brown-Ladner equation increases with the reactor temperature. ¹³C-n.m.r. spectra of the oils indicates that the long aliphatic chains present decrease in both number and length as the reactor temperature increases. The molecular weight and viscosity of the oil as well as the percentage of polar compounds in the oil decrease with increasing temperature.     

The chemical nature of a supercritical gas extract including comparison with other coal liquids

A supercritical gas extract of an Australian bituminous coal was separated into oil, asphaltene and pre-asphaltene. The oil was further separated by chromatography into three fractions. Average structure data for each fraction are reported based on NMR spectroscopy combined with elemental, molecular weight and functional group analyses. Unsubstituted alkyl chains (> C₈) were found in every fraction of the extract. The presence of n-alkanes, 1-alkenes and phenyl-n-alkanes were shown. The supercritical gas extract was compared with a flash pyrolysis tar and with hydrogenation liquids from the same coal. The supercritical gas extract and the flash pyrolysis tar had a similar distribution between oil, asphaltene and pre-asphaltene, but the oil, asphaltene and pre-asphaltene from the supercritical gas extract were less aromatic and contained fewer heteroatoms than these fractions from the flash pyrolysis tar. The supercritical gas extract has a higher H/C atomic ratio, higher heteroatom content and a higher percentage of carbon in long unsubstituted alkyl chains than hydrogenation liquids produced at 400°C and 450 °C. The oil/asphaltene ratio and the aromaticity of the oil and asphaltene from the supercritical gas extract were intermediate between those obtained for the two hydrogenation liquids.     

Hydrogenation of liddell vitrinite: Effects of metal halide catalysts in the temperature range 200–480°C

A vitrinite concentrate prepared from the Liddell Seam (high volatile bituminous coal, NSW, Australia) has been hydrogenated in an unstirred 50 cm³, batch autoclave at reaction temperatures between 200 and 480°C in the presence of metal halides (SnCl₁ or ZnCl₁) and/or alumina (α-Al₁O₃). A vehicle was not used. The influence of reaction temperature, metal halide and alumina on the composition of the products was studied by gas chromatography (GC), gel permeation chromatography (gpc), ¹H solution and ¹³C solid-state cross polarization (CP) nuclear magnetic resonance (nmr) spectroscopy and optical microscopy.The metal halides lower the temperature at which softening and agglomeration of vitrinite takes place. The resultant plastic isotropic material forms mesophase at temperatures above 400°C unless an inert diluent, i.e. alumina, is added. The alumina inhibits reactions involved in the formation of mesophase which would otherwise compete with hydrogenation reactions that yield hexane soluble material (oil).Above 400°C carbon monoxide, carbon dioxide and C₁-C₅ alkanes are the principal gaseous products. At lower temperatures, in the presence of alumina, ethylene is formed in the catalysed experiments; the ethylene is converted to ethane at higher temperatures. The structure of the hexane soluble products derived from vitrinite is also temperature dependent. Above 420°C much of the aliphatic component decomposes to yield further quantities of hydrocarbon gases. Tin(II) chloride and zinc chloride produce hexane soluble products of similar molecular composition, which suggests that they operate through a similar mechanism.The addition of alumina to the reaction mixture results in a more aromatic liquid product with shorter aliphatic carbon chains. Whether or not alumina is present, the aromaticity of the solid residues increases with increase in hydrogenation temperature. Thus the increased aromaticity of the liquid products is not caused by the extraction of a greater proportion of aromatic material from the coal with increase in the hydrogenation temperature. It follows that with increase in hydrogenation temperature an increasing proportion of the aliphatic material becomes transformed into aromatic compounds and/or gas.In summary, the results show that over a wide range of temperatures (200–480°C) the structure of the hexane soluble product depends on the thermal stability of the products and the degree of competition from reactions leading to mesophase formation, and not on the nature of the halide catalyst.     

Studies on thermal cracking behavior of residual feedstocks in a batch reactor

Thermal cracking of residual fractions has gained interest of refiners due to increasing demand of middle distillates and at the same time decline in demand of fuel oils. The present study is an attempt to gain deeper insight into the thermal cracking behavior of residual feedstocks in terms of certain key characteristics. Laboratory scale experiments on a 400 ml capacity stainless steel batch reactor were conducted with four residual feedstocks of Indian and Middle East origin—North Gujarat short residue (NGSR), Visbreaker feed from Mathura refinery (MVBF), Bombay High short residue (BHSR) and Asphalt from Haldia refinery (HRA), with asphaltene content varying in the range 1.85-10.15 wt%. The cracked products were separated by distillation up to 500 ^°C. The distillate (500 ^°C-) was analyzed by ASTM D2887 (SIMDIST) method and obtained data were classified into lumps, namely Gas (C₅-), Gasoline (IBP-150 ^°C), Light Gas Oil (150-350 ^°C) and Vacuum Gas Oil (350-500 ^°C) prior to detailed data analysis. The analysis of results reveals that the thermal cracking of petroleum residues follows first order kinetics. The rate constants and activation energies have also been estimated.     

Comparative analysis of pyrolysis oils and its subfractions under different atmospheric conditions

In this paper comparative analysis of bio-oils and their subfraction from static, sweeping gas and steam pyrolysis of apricot pulp, a food industry waste, was investigated. Experimental studies were conducted in a well-swept fixed-bed reactor with a heating rate of 5 °C min^{− 1}, to a final pyrolysis temperature of 550 °C. The oil yield which was 22.4% at the static atmosphere reached to the value of 23.2% in the sweeping gas atmosphere by using 100 cm³ min^{− 1} N₂ flow rate. The yield of liquid product in steam pyrolysis was higher (27.2%) than the static and inert gas atmosphere.The elemental analyses of the pyrolysis oils were determined, and the chemical compositions of the oils were investigated using chromatographic and spectroscopic techniques. The liquid products were fractionated into pentane solubles and insolubles (asphaltenes). Pentane solubles were then solvent fractionated into pentane, toluene, and methanol subfractions by fractionated column chromatograpy. The aliphatic subfractions of the oils were then analysed by capillary column gas–liquid chromatography and GC/MS. For further structural analysis, the pyrolysis oils' aliphatic, aromatic and polar subfractions were conducted using FTIR and ¹H NMR spectra.     

Effect of residence time spectrum in the oligomerisation of isobutene from mixed butenes

The influence of the residence time spectrum on the conversion, selectivity and product composition in the oligomerisation of isobutene from mixed butenes in a continuous stirred-tank reactor was studied at a temperature of 65 °C and impeller Reynolds number in the range of 36 × 10⁴ to 67 × 10⁴. The average residence time and its spectrum affected the conversion of olefins in the feed gas, the selectivity and the octene yields. It was established that for best yields of 2,4,4-trimethyl pent-1-ene obtained from the mixed butenes feed, the residence time spectrum should be as narrow as possible. The results indicate that for good yield and selectivity in iso-octene production from a C₄ olefin fraction, Reynolds number of mixing of around 68 × 10⁴ or slightly higher would be most desirable.     

Thermoplastic properties of coals carbonized at elevated pressures: effects of waste inorganic materials (GOB)

Thermal behaviour of coal-derived asphaltenes was investigated under atmospheric pressure by thermogravimetry (TG). The weight loss is rapid from 300 to 500°C and is slow above 500°C. The asphaltene comparatively low in molecular weight shows the greater weight loss. The temperature at which the differential thermogravimetry peak appears, T_m, correlates to the asphaltene aromaticity: the asphaltene comparatively high in aromaticity shows higher T_m. Of the residual asphaltene after heating up to 600°C, the obtained crystallite thickness through the c-axis direction (Lc₀₀₂) has a correlation with the molecular weight of the parent asphaltene: the parent asphaltene comparatively low in molecular weight produces residual asphaltene of larger Lc₀₀₂.     

Alkyl aryl ethers in lignite solubilization: 2. Analysis of oil fractions

The FT-i.r. and ¹H n.m.r. spectroscopic analyses of oils or maltenes from a Spanish lignite (Utrillas, Teruel), are reported. These oils were obtained by depolymerization with alkyl aromatic ethers (anisole, 3-methylanisoleand 1,3-dimethoxybenzene) catalyzed by Lewis acids ZnCl₂, AlCl₃, SbCl₃and BF₃ (as boron trifluoride etherate), at atmospheric pressure and temperatures <220 °C. Bands due to aromatic ethers in the i.r. and n.m.r. spectra of the oils obtained by depolymerization indicate solvent incorporation. Oils obtained by direct lignite extraction showed 25% aromatic H and some H_α (≈3%) without OH groups. These appeared in some oils obtained by depolymerization with AlCl₃ and were due to secondary reactions with the aromatic extract. Oils derived from processes with good yields showed increases in aromaticity. The extent of substitution of aromatic rings in oils obtained by depolymerization was less than for oils directly extracted. All the oils studied show a low degree of condensation.     

Use of nitrogen to improve stability of virgin olive oil during storage

Experiments were carried out to study the possibility of improving the stability of extra virgin olive oil by using nitrogen as a conditioner gas during storage. With this aim, virgin olive oil samples, obtained from Leccino and Coratina cultivars, were stored in the dark, in closed bottles conditioned with air or nitrogen at 12–20 and 40°C. Results indicated that the FFA percentage increased over 1% only when oils were stored at 40°C. The PV and the K ₂₃₂ value (light absorbance at 232 nm) of oils increased over the limit value allowed by European Union law when the bottles were only partly filled and air was the conditioner gas. The use of nitrogen as conditioner gas helped to avoid this risk during 24 mon of storage at 12–20°C. The total phenolic content of both cultivars oils decreased during storage because their oxidation protected the oils from autoxidation. The content of total volatile compounds in oils decreased continuously during storage at 12–20°C, whereas it increased over 10 (Coratina cv.) and 15 (Leccino cv.) mon and then diminished when the storage temperature was 40°C. The same behavior, i.e., increase then decrease, was ascertained for trans-2-hexenal. The hexanal content of oils increased continuously during storage because this compound is formed by the decomposition of the 13-hydroperoxide of linoleic acid.     

Ethoxylation of Fatty Acids Fractions of Overused Vegetable Oils

Unsaturated and saturated fatty acids fractions were separated from overused sunflower and olein oils, which are considered to be a waste, in order to use them in the preparation of valuable ethoxylated fatty derivatives with low cost of preparation. Fatty acid fractions were ethoxylated using ethylene oxide gas in the presence of 1% K₂CO₃ catalyst at 120 and 180 °C for 5, 6 and 7 h. Also fresh stearic acid and a fresh mixture of stearic acid:sunflower oil (1:1 wt/wt) were ethoxylated at 180 °C for 6 h for comparison. Results showed that effective fatty derivatives could be obtained from overused oils which may give an economic retrieval. Also, reaction conditions have different effects on the properties of the produced derivatives where the best results were obtained for samples prepared at 180 °C for 6 and 7 h. Ethoxylating the saturated fatty acids fraction of both overused oils especially olein oil gave better results than those of the unsaturated fraction, the ethoxylated fresh stearic acid and the ethoxylated fresh mixture of stearic acid:sunflower oil (1:1 wt/wt).     

The solubility of hydrogen in aliphatic amines

The solubility of hydrogen in ammonia, monomethylamine, monoethylamine and n-propylamine was determined at temperatures from ?70°C to 25°C and in 1,2-propanediamine and 1,2-ethanediamine over the temperature ranges ?25°C to 11°C and 25°C to 34°C respectively. Measurements were made at total pressures up to 300 psig. The solubility data were correlated in terms of Henry's law and the solubilities are in the range 1 × 10^?5 to 3 × 10^?4 mole fraction at a hydrogen partial pressure of 1 atmosphere. The measured solubility data were used to extend a correlation proposed by Yen and McKetta. This revised correlation may be used to estimate the solubility of hydrogen in polar, associated amines.     

Thermal Damage on LX‐04 Mock Material and Gas Permeability Assessment

RM‐04‐BR, a mock material for the plastic‐bonded HMX‐based explosive LX‐04, is characterized after being thermally damaged at 140 °C and 190 °C. We measured the following material properties before and after the thermal experiments: sample volume, density, sound speed, and gas permeability in the material. Thermal treatment of the mock material leads to de‐coloring and insignificant weight loss. The sample expanded, resulting in density reductions of 1.0% to 2.5% at 140 °C and 190 °C, respectively. Permeability in the mock samples was found to increase from 10⁻¹⁶ to 10⁻¹⁵ m², as the porosity increased. The permeability measurements are well represented by the Blake‐Kozeny equation for laminar flow through porous media. The results are similar to the gas permeability in PBX‐9501 obtained by other researchers [1, 2].     

Trehalose‐based thermosetting resins. I. Synthesis and thermal properties of trehalose vinylbenzyl ether

Trehalose vinylbenzyl ether was synthesized from trehalose and p‐chloromethylstyrene (CMS) in DMSO in the presence of powdered NaOH. The structure of the product was characterized by IR and ¹H NMR spectroscopy. Degree of substitution (DS) on a trehalose unit calculated from the ¹H NMR spectrum varied from 2.4 to 3.2 by changing the feed ratio of p‐chloromethylstyrene to trehalose. Thermal properties of the resin were analyzed by differential scanning calorimetry (DSC). DSC analysis revealed that the resin DS 2.4 has one exothermal peak at 132°C, whereas the resins DS 2.8 and 3.0 have two exothermal peaks. Furthermore, the resin DS 3.2 was found to have only one exothermal peak at 191°C. Dynamic mechanical analysis (DMA) and thermomechanical analysis (TMA) revealed that the cured resin has one transition, implying a glass transition. Biodegradability was assayed by the BOD method, and several percent of the cured resin was found to be degraded with activated sludge for 50 days. Further degradation, however, was not observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 46–51, 2004     

Studies of thermal oxidative degradation of polypropylene impact copolymer using the temperature rising elution fractionation method

Thermal oxidative degradation of polypropylene impact copolymer has been studied with its fractions obtained using the temperature rising elution fractionation method. The fractions were analyzed using ¹³C NMR, Fourier transform infrared and differential scanning calorimetry measurements, and the chemical structure, isotacticity, conformation and melting point were investigated. It is found that these fractions are composed of a homopolymer or a polymer blend of polypropylene, polyethylene and ethylene–propylene copolymer. The thermal oxidative degradation of each fraction was carried out at 130 °C, and the degradation progress was estimated by the change of molecular weight distribution (from gel permeation chromatography curves). The rate of degradation is found to be dominated by the content of tertiary C? H bonds (propylene unit) and the existence of 3₁ helix conformation corresponding to a crystalline polypropylene part in each fraction. The latter is more evident leading to the degradation reaction path with a lower activation energy. Copyright © 2007 Society of Chemical Industry     

Novel heat resistant methyl‐tri(phenylethynyl)silane resin: Synthesis,characterization and thermal properties

Methyl‐tri(phenylethynyl)silane (MTPES) was successfully synthesized by the reaction of lithium phenylacetylide with methyltrichlorosilane. The structure was characterized by HRMS, FTIR, ¹H‐NMR, ¹³C‐NMR, ²⁹Si‐NMR, and elementary analysis. Thermal cure process was monitored by DSC, DMA, and FTIR. MTPES was heated to free flowing liquid around 130°C and thermally polymerized at 327–377°C to form thermoset. Thermal and oxidative properties were evaluated by TGA analysis. Thermoset exhibits extremely high heat‐resistance and TGA curve in nitrogen shows the temperature of 5% weight loss (Td₅) of 695°C and total weight loss at 800°C of 7.1%. TGA shows a high Td₅ of 565°C even in air, although the total weight loss at 800°C was 56.1% of the initial weight, much higher than that in nitrogen. The high heat resistance of MTPES was ascribed to crosslinking reaction concerning ethynyl groups. Aging studies performed at elevated temperatures in air on a thermoset showed that MTPES is oxidatively stable to 300°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2488–2492, 2006     

An Industrial Scale Dehydration Process for Natural Gas Involving Membranes

An industrial scale dehydration process based on hollow fiber membranes for lowering the dew point of natural gas is described in this paper. A pilot test with the feed flux scale of 12×10⁴ Nm³/d was carried out. Dew points of –8 °C∼–13 °C at a gas transport pressure in the pipeline of 4.6M Pa and methane recovery of more than 98% were attained. The water vapor content of the product gas could be maintained around 0.01 vol% during a continuous run of about 700 hours. The effects of feed flux and operation pressure on methane recovery and water vapor content were also investigated. Additionally, some auxiliary technologies, such as a full‐time engine using natural gas as fuel and the utilization of vent gas in the process, are also discussed. A small amount of the vent gas from the system was used as a fuel for an engine to drive vacuum pumps, and the heat expelled from the engine was used to warm up the natural gas feed. The whole system can be operated in a self‐sustainable manner from an energy point of view, and has a relatively high efficiency in the utilization of natural gas.     

Correlation of microautoclave and 1H n.m.r. measurements of coal liquefaction solvent quality

Some 467 coal liquefaction process oils, having nominal boiling points within the range 473–808 K (200–535 °C), were assayed for donor solvent quality in 577 microautoclave tests using three different sets of reaction conditions. Proton distributions were also determined on each sample by ¹H n.m.r. Microautoclave coal conversions and proton distributions, correlated using multiple linear regressions, give similar measurements of solvent quality over a wide range of solvents. Donor solvent quality (as measured by microautoclave coal conversion) increases with increasing hydroaromatic content and with decreasing aromaticity and paraffinicity. As they were designed to do, the different microautoclave tests measure different solvent properties. Above a certain level of solvent quality, microautoclave extractions are insensitive to solvent quality differences. However, ¹H n.m.r. can differentiate between these high quality solvents, and the data can be related to differences in process performance. Advantages of using ¹H n.m.r. for donor solvent quality measurements are discussed.     

Raman study of the microstructure changes of phenolic resin during pyrolysis

After curing, phenol‐formaldehyde resins were post‐cured at 160°C, and then carbonized and graphitized from 300°C to 2400°C. The structure of the resulting carbonized and graphitized resins were studied using X‐ray diffraction and Raman spectroscopy. Thermal fragmentation and condensation of the polymer structure occurred above 300°C. The crystal size of the cured phenolic resins increased with an increase in temperature. The crystal size increased from 0.997 nm to 1.085 nm when the heat‐treatment temperature rose from 160°C to 500°C. Above 600°C, the original resin structures disappeared completely. Below 1000°C, the stack size (L_c) increased very slowly. The values increased from 0.992 to 1.192 nm when the heattreatment temperature rose from 600°C to 1000°C. Above 1000°C, the stack size showed an increase with the increase in heat‐treatment temperature. The values increased from 1.192 to 2.366 nm when the temperature rose from 1000°C to 2400°C. The carbonized and graphitized resins were characterized using Raman spectroscopy. The Raman spectrra were recorded between 700 and 2000 cm⁻¹. Below 400°C, there were no carbon structures in the Raman spectra analysis. Above 500°C, G and D bands appeared. Raman spectra confirmed progressive structure ordering as heat‐treatment temperature increased. The frequency of the G band of all carbonized and graphitized samples shifted to 1600 cm⁻¹ from the 1582 cm⁻¹ of graphite. At the same temperature, the D band shifted to 1330 cm⁻¹ from the 1357 cm⁻¹ of the imperfect carbon. In the curve fitting analysis of the Raman spectra, a Gaussian shaped band centered at 1165 cm⁻¹ was included. This band has not been described before in the literature and is attributed to disordered structures, which are formed from the original polymeric structures. These polymeric structures formed unknown disordered structures and remained in the carbonized phenolic resins. Above 1800°C, this band disappeared completely. But, a weak peak is present near 1620 cm⁻¹. This indicated that those disoriented molecules and some disordered carbons were removed as volatiles or repacked into the glassy carbon structures during graphitization. The carbonized and graphitized phenolic resins were found to correspond to low order sp² bonded carbon, but cannot be considered as truly glassy or amorphous carbon materials since they have some degree of order in the basal plane.