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Geophysical evidence for gas hydrates in the deep water of the South Caspian Basin, Azerbaijan
03 Gaseous fuels (sources, properties, Kinetics of transesterification in rapeseed oil to 02/00858 biodiesel fuel as treated in supercritical methanol Kusdiana, D. and Saka, S. Ate/, 2001, 80, (5), 693-698. A kinetic study in free catalyst transesterification of rapeseed oil was made in subcritical and supercritical methanol under different reaction conditions of temperatures and reaction times. Runs were made in a bath-type reaction vessel ranging from 200°C in subcritical temperature to 500°C at supercritical state with different molar ratios of methanol to rapeseed oil to determine rate constants by employing a simple method. As a result, the conversion rate of rapeseed oil to its methyl esters was found to increase dramatically in the supercritical state, and reaction temperature of 350°C was considered as the best condition, with the molar ratio of methanol in rapeseed oil being 42. Recovery of phenol and its derivatives 02/00857 Sato, S. e/ rrl. Jpn. Kokai Tokkyo Koho JP 2001 72,634 (Cl. CO7C37/ 72), 21 Mar 2001, Appl. 1999/253,750, 8 Sep 1999. 7. (In Japanese) PhOH, its derivatives, and hydrocarbon oils are separated and purified by mixing their mixtures with alcohols, mixing the mixtures with Hz0 to separate them into aqueous phases containing phenols and oily phases containing hydrocarbon oils, distilling the aqueous phases to separate them into alcohols and mixtures containing HrO and phenols, returning alcohols to the process above, treating the remaining mixtures with extracting agents to separate them into oily phases containing phenols and the extracting agents and aqueous phases containing HzO, distilling the oily phases to separate them into extracting agents and mixtures containing phenols, returning the extracting agents to the extraction process above, taking phenols out of the system, and washing hydrocarbon oils with the remaining aqueous phases. HzO, alcohols, and extracting agents are recycled in the process and high-purity phenols and hydrocarbon oils are obtained from oils, e.g. coal liquefaction oils. Removal of tarry liquid from solid-liquid mixtures 02fOO858 Suzuki, S. Jpn. Kokai Tokkyo Koho JP 2001 114,709 (Cl. C07B63/00), 24 Apr 2001, Appl. 19991296,490, 19 Ott 1999;. 3. (In Japanese) Tarry liquid is removed from its solid mixtures by washing with poor organic solvents using centrifugal filters. The method is useful for separation of solid products from tar-containing reaction mixtures. A slurry containing 3-carboxyl-2-trifluoromethyl-2-hydroxy-l-butanal-l(4-chloro-2-fluoro-5-hydroxyphenylhydrazine) triethylamine salt (I), tar, and PhCl was washed with PhCl m a centrifugal filter to give I of -94% purity. 02/00859 Unleaded synthetic gasoline Bai, S. and Zhang, J. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,265,415 (Cl. ClOLl/O4), 6 Sep 2000, Appl. 2,000,105,593, 3 Apr 2000. 4. (In Chinese) The gasoline contains MeOH 34-45, MePh 16-20, xylene 18-25, straight-run gasoline 18-35, condensate oil or topped oil O-6%.
03
GASEOUS FUELS Sources, properties, recovery, treatment
Composition and origin of coalbed gases in the 02/00880 Lower Silesian basin, southwest Poland Kotarba, M.J. and Rice, D.D. Appl. Geochem., 2001, 16, (7-8), 895-910. Coal-bed gases in the Lower Silesian Coal Basin (LSCB) of Poland are highly variable in both their molecular and stable isotope compositions. Geochemical indexes and stable isotope ratios vary within the following ranges: hydrocarbon (C&c) index &c=CH4/(CzHr,+ CsHs) from 1.1 to 5825, wet gas (C,,) index C2+=(CsH,+ CsHs, CIHIO+ CsHtz)/ (CHI+ CzH6+ CsHs+ ChHta+ CsHt2) 100 (%) from 0.0 to 48.3%, CO,-CH+$CDMf) index CDMI-C02/(C02+ CHI) 100 (%) from 0.1 to 99.9%, 6 C(CH4) from -66.1 to -24.6b. SD(CH,) from -266 to -117X+, 6”C(CzHs) from -27.8 to -22.8& and 6”C(C02) from -26.6 to -16.8Y~. Isotopic studies reveal the presence of three genetic types of natural gases: thermogenic (CH4, higher gaseous hydrocarbons, and CO& endogenic CO 2, and microbial CHI and COz. Thermogenic gases resulted from coalification processes, which were probably completed by Late Carboniferous and Early Permian time. Endogenic CO* migrated along the deep-seated faults from upper mantle and/or magma chambers. Minor vols. of microbial CHI and COz occur at shallow depths close to the abandoned mine workings. ‘Late-stage’ microbial processes have commenced in the Upper
recovery,
treatment)
Cretaceous and are probably active at present. However, depth-related isotopic fractionation which has resulted from physical and physicochemical (e.g. diffusion and adsorptionldesorption) processes during gas migration cannot be neglected. The strongest rock and gas outbursts occur only in those parts of coal deposits of the LSCB which are dominated by large amounts of endogenic CO:. 02lOO881 Determination of octane numbers of gasoline compounds from their chemical structure by ‘% NMR spectroscopy and neural networks Meusinger, R. and Moros, R. Fuel, 2001, 80, (5) hl33621. A new theoretical model has been developed which explains the association between the molecular structure and the knock resistance of individual gasoline compounds convincingly. The constitutions of more than 300 individual gasoline components were correlated with their knock rating (Blending Research Octane Number, BRON) simultaneously. “C NMR spectra of all compounds were binned in 28 chemical shift regions of different size. The number of individual carbon signals of the nearly 2500 carbons was counted in each shift region and was combined with the information about the presence or absence of the structure groups Oxygen, Rings, Aromatics, aliphatic Chains and oLefins (ORACL). These numbers were used for the encoding of the chemical structure. The relations between the structure information and the knock ratings were determined using an artificial neural network. For a validation data set of 50 individual chemical compounds from various substance classes consisting only of C, H and 0 a good agreement was found with their experimentally determined BRON (R = 0.933). 02lOO882 Geophysical evidence for gas hydrates in the deep water of the South Caspian Basin, Azerbaijan Diaconescu, CC. er nl. Marine and Perro/rt~v~ Geology, 200 I. 18, 13). 209-22 I New 2-D seismic reflection data from the South Caspian Sea, offshore Azerbaijan, document for the first time in the deep water (up to 650 m) of this area, the presence of gas hydrates. Geophysical evidence for gas hydrates consists of a shallow (300-500 m below seafloor) zone of pronounced high velocity (-2100 m/s) as compared with the surrounding sediments (1550-1600 m/s). This zone appears on the seismic data as a depth-limited (-200 m thick) layer extending down the flank of an elongate structural high, and displays seismic hlanking effects on the sedimentary section. A strong positive-polarity (R, -. 0.123) reflector marks the top of this velocity anomaly, and is Interpreted as the top of the gas hydrate layer. Similarly, a high-amplitude (R, _ 0.1 I). negative polarity reflector coincides with the base of the high-velocity layer. and is interpreted as the base of the hydrate zone. Both the top and bottom of the hydrate layer approximately parallel the seafloor bathymetry. and cut discordantly across the stratigraphic section, suegestmg that the two reflectors are thermobaric and not stratigraph;c interfaces. Decreasing amplitude with offset at the base of the gas hydrate layer may indicate the accumulation of free gas beneath this interface These gas hydrates fall within the hydrate stability field predicted from thermobaric modeling for the South Casptan Basin, but typically in thinner layers than would be expected from theoretical calculations The minimum predicted water depth that allows hydrate formation is -150 m, and the maximum predicted thickness of the gas hydrate stability field is -1350 m. 02100883 Hexadecane-cyclohexane copyrolysis Hajekova, E. and Bajus, M. Per. Cocrl, 2000. 42, (I). 9916. Kinetics of decomposition and product formation were studied during pyrolysis of pure cyclohexane and during pyrolysis of hexadecane cyclohexane mixture (1:l wt). Experiments were carried out at 720800°C at steam to hydrocarbon ratio 1:l wt, atmospheric pressure, in a stainless steel flow reactor. Initiation-inhibiting effect of hydrocarbons was confirmed at their copyrolysis. The rate of cyclohexane decomposition in the mixture has increased nine-fold at lower temperatures and five-fold at higher temperatures in comparison with pyrolysis of pure cyclohexanei Pure cyclohexane had an activation energy at pyrolysis 347 kJmol The activation energy of, cyclohexane decomposition in the mixture decreased to 277 kJmol and the activation energy of hexadecane decomposition in the mixture increased to 256 kJmol ‘, Ethylene, 1,3-butadiene, propene, methane and hydrogen were prevailing in gaseous products of pyrolysis. In pyrolysis of mixture, the ratio of ethylene to butadiene increased. Selectivity of butadiene fell to the level of methane and propene. I-Alkenes, from I-pentene to pentadecene had a significant position in the liquid. The formation of aromatics benzene and toluene was registered They indicate a course of reactions of dehydrogenation and condensation The amounts of formed 1,3-butadiene and methane were higher, the amounts of ethylene, hydrogen and carbon oxides were lower than they shoufd be, when calculated on the basis of additivity. The differences are explained by priority scission of cyclohexane via cyclohexyl radical in the presence of active radical from hexadecane, as well as hy Fuel and Energy Abstracts
March 2002
105
03
GASEOUS FUELS Sources, properties, recovery, treatment
Composition and origin of coalbed gases in the 02/00880 Lower Silesian basin, southwest Poland Kotarba, M.J. and Rice, D.D. Appl. Geochem., 2001, 16, (7-8), 895-910. Coal-bed gases in the Lower Silesian Coal Basin (LSCB) of Poland are highly variable in both their molecular and stable isotope compositions. Geochemical indexes and stable isotope ratios vary within the following ranges: hydrocarbon (C&c) index &c=CH4/(CzHr,+ CsHs) from 1.1 to 5825, wet gas (C,,) index C2+=(CsH,+ CsHs, CIHIO+ CsHtz)/ (CHI+ CzH6+ CsHs+ ChHta+ CsHt2) 100 (%) from 0.0 to 48.3%, CO,-CH+$CDMf) index CDMI-C02/(C02+ CHI) 100 (%) from 0.1 to 99.9%, 6 C(CH4) from -66.1 to -24.6b. SD(CH,) from -266 to -117X+, 6”C(CzHs) from -27.8 to -22.8& and 6”C(C02) from -26.6 to -16.8Y~. Isotopic studies reveal the presence of three genetic types of natural gases: thermogenic (CH4, higher gaseous hydrocarbons, and CO& endogenic CO 2, and microbial CHI and COz. Thermogenic gases resulted from coalification processes, which were probably completed by Late Carboniferous and Early Permian time. Endogenic CO* migrated along the deep-seated faults from upper mantle and/or magma chambers. Minor vols. of microbial CHI and COz occur at shallow depths close to the abandoned mine workings. ‘Late-stage’ microbial processes have commenced in the Upper
recovery,
treatment)
Cretaceous and are probably active at present. However, depth-related isotopic fractionation which has resulted from physical and physicochemical (e.g. diffusion and adsorptionldesorption) processes during gas migration cannot be neglected. The strongest rock and gas outbursts occur only in those parts of coal deposits of the LSCB which are dominated by large amounts of endogenic CO:. 02lOO881 Determination of octane numbers of gasoline compounds from their chemical structure by ‘% NMR spectroscopy and neural networks Meusinger, R. and Moros, R. Fuel, 2001, 80, (5) hl33621. A new theoretical model has been developed which explains the association between the molecular structure and the knock resistance of individual gasoline compounds convincingly. The constitutions of more than 300 individual gasoline components were correlated with their knock rating (Blending Research Octane Number, BRON) simultaneously. “C NMR spectra of all compounds were binned in 28 chemical shift regions of different size. The number of individual carbon signals of the nearly 2500 carbons was counted in each shift region and was combined with the information about the presence or absence of the structure groups Oxygen, Rings, Aromatics, aliphatic Chains and oLefins (ORACL). These numbers were used for the encoding of the chemical structure. The relations between the structure information and the knock ratings were determined using an artificial neural network. For a validation data set of 50 individual chemical compounds from various substance classes consisting only of C, H and 0 a good agreement was found with their experimentally determined BRON (R = 0.933). 02lOO882 Geophysical evidence for gas hydrates in the deep water of the South Caspian Basin, Azerbaijan Diaconescu, CC. er nl. Marine and Perro/rt~v~ Geology, 200 I. 18, 13). 209-22 I New 2-D seismic reflection data from the South Caspian Sea, offshore Azerbaijan, document for the first time in the deep water (up to 650 m) of this area, the presence of gas hydrates. Geophysical evidence for gas hydrates consists of a shallow (300-500 m below seafloor) zone of pronounced high velocity (-2100 m/s) as compared with the surrounding sediments (1550-1600 m/s). This zone appears on the seismic data as a depth-limited (-200 m thick) layer extending down the flank of an elongate structural high, and displays seismic hlanking effects on the sedimentary section. A strong positive-polarity (R, -. 0.123) reflector marks the top of this velocity anomaly, and is Interpreted as the top of the gas hydrate layer. Similarly, a high-amplitude (R, _ 0.1 I). negative polarity reflector coincides with the base of the high-velocity layer. and is interpreted as the base of the hydrate zone. Both the top and bottom of the hydrate layer approximately parallel the seafloor bathymetry. and cut discordantly across the stratigraphic section, suegestmg that the two reflectors are thermobaric and not stratigraph;c interfaces. Decreasing amplitude with offset at the base of the gas hydrate layer may indicate the accumulation of free gas beneath this interface These gas hydrates fall within the hydrate stability field predicted from thermobaric modeling for the South Casptan Basin, but typically in thinner layers than would be expected from theoretical calculations The minimum predicted water depth that allows hydrate formation is -150 m, and the maximum predicted thickness of the gas hydrate stability field is -1350 m. 02100883 Hexadecane-cyclohexane copyrolysis Hajekova, E. and Bajus, M. Per. Cocrl, 2000. 42, (I). 9916. Kinetics of decomposition and product formation were studied during pyrolysis of pure cyclohexane and during pyrolysis of hexadecane cyclohexane mixture (1:l wt). Experiments were carried out at 720800°C at steam to hydrocarbon ratio 1:l wt, atmospheric pressure, in a stainless steel flow reactor. Initiation-inhibiting effect of hydrocarbons was confirmed at their copyrolysis. The rate of cyclohexane decomposition in the mixture has increased nine-fold at lower temperatures and five-fold at higher temperatures in comparison with pyrolysis of pure cyclohexanei Pure cyclohexane had an activation energy at pyrolysis 347 kJmol The activation energy of, cyclohexane decomposition in the mixture decreased to 277 kJmol and the activation energy of hexadecane decomposition in the mixture increased to 256 kJmol ‘, Ethylene, 1,3-butadiene, propene, methane and hydrogen were prevailing in gaseous products of pyrolysis. In pyrolysis of mixture, the ratio of ethylene to butadiene increased. Selectivity of butadiene fell to the level of methane and propene. I-Alkenes, from I-pentene to pentadecene had a significant position in the liquid. The formation of aromatics benzene and toluene was registered They indicate a course of reactions of dehydrogenation and condensation The amounts of formed 1,3-butadiene and methane were higher, the amounts of ethylene, hydrogen and carbon oxides were lower than they shoufd be, when calculated on the basis of additivity. The differences are explained by priority scission of cyclohexane via cyclohexyl radical in the presence of active radical from hexadecane, as well as hy Fuel and Energy Abstracts
March 2002
105