摘要:

In this article two oxidation reactions of the oxidation of petroleum residues are considered: catalytic oxidation of tar to bitumens and oxidation of asphaltene concentrates under radiation.

ISSN:0884-3759    

DOI:10.1080/08843759108942257

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Aggregative flotation tests of gas-flaming coal were carried out in a laboratory flotation machine and a flotation column. Aggregation of coal feeds was carried out using as a collector unemulsified and emulsified kerosene at dosages of 130 and 10 kg/t, respectively. The results of the aggregative flotation showed that it is possible to beneficate gas-flaming coal at a huge dosage of the collector, the flotation response of which is very low. Preemulsification of kerosene caused a distinct decrease of its consumption. The efficiency of aggregative flotation of coal was higher in the flotation machine; however, the flotation selectivity of the finest feeds (−0.13 and −0.23 mm) in the column was a little better. The influence of the size of coal grains on coal recovery and ash reduction both in the flotation machine and flotation column was interpreted as dependent on the decrease of the contact plane of aggregates formed by coal grains with air bubbles and on the size of these aggregates.

ISSN:0884-3759    

DOI:10.1080/08843759108942258

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The direct conversion of methane to petrochemical feedstocks and to transportation fuels, by-passing the synthesis gas step, is a continuing challenge in catalytic process development. There are high economic incentives to commercialize direct methane conversion to formaldehyde and methanol, and even higher economic incentives for conversion to ethylene and aromatic hydrocarbons. Current process developments in the direct conversion of methane to methanol, formaldehyde, ethylene and aromatics are reviewed. The processes are discussed in terms of process conditions, catalysts used, methane conversion, and product selectivities.

ISSN:0884-3759    

DOI:10.1080/08843759108942259

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Kinetic studies of supercritical extraction experiments to recover organic material from Turkish Göynük and U.S. Western Reference oil shales were carried out. Solubilization curves of both shales were studied in two regions; a sharply rising part reaching an intermediate state solubilization and a part where gradual changes were observed at extended periods. Organic material recovered from demineralized oil shales when the intermediate state was attained was much lower than the percentage of organic material recovered from the original oil shale. Kinetic analysis indicated that the interaction in the first region produced primary products from the organic material of the shale while the interaction in the second region contained secondary reactions among the primary products obtained before the intermediate state was attained.

ISSN:0884-3759    

DOI:10.1080/08843759108942260

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper describes the chloromethylation of petroleum residua and the subsequent conversion of the products to vulcanizing algents and ion exchange materials. Properties of the products are given in some detail.

ISSN:0884-3759    

DOI:10.1080/08843759108942261

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The hydroprocessing reactions of kraft lignin and four of its model compounds, o-hydroxydiphenylmethane (OHD), diphenylmethane (DPM), 4-phenoxyphenol (PP), and 4-methylguaiacol (MG) were studied over a sulfided CoMo/γ-Al2O3catalyst. The reactions of OHD were also studied over sulfided Ni-Mo/γ-Al2O3, Ni-W/γ-Al2O3, and Ni-Mo/zeolite catalysts. Reaction pathways, kinetics, and catalyst deactivation were resolved. Experiments with the actual kraft lignin substrate showed that catalytic hydroprocessing led to higher yields of single-ring products and lower yields of light gas compared to hydropyrolysis alone. The CoMo/γ-Al2O3catalyst increased the selectivity to non-coking monophenolics and hydrocarbon products. The model compound results permitted interpretation. The hydroxyl substituents on OHD and PP directed bond cleavage strongly. The atom linking the two aromatic rings remained almost exclusively with the unsubstituted ring after cleavage. The substituent increased reactivity by at least an order of magnitude. The catalytic reactions of OHD, DPM, and PP were 103-104times faster than their thermal reactions. Deoxygenation was appreciable in these reactions and in the catalytic hydroprocessing of MG. Collectively, these results suggest that the improved activity and selectivity in catalytic lignin liquefaction is due to enhancement of link cleavage and the transformation of coking dioxygen-substituted phenolic coke pecursors (e.g., catechols and guaiacols) to non-coking phenols. Hydrotreating catalysts with alumina supports appear suitable for lignin conversion. The highly active and rapidly deactivating zeolite-supported hydrotreating catalyst afforded a complex mixture of products. Regeneration of the alumina-supported catalysts would be required.

ISSN:0884-3759    

DOI:10.1080/08843759108942262

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The catalytic activity of nickel, a trace metal indigenous to residuum used in coprocessing of coal and petroleum residuum, was investigated in hydrogenation and heteroatom removal reactions using model systems at coprocessing conditions. Hydrocarbons and heteroatomic species of S, N, and O having similar chemical structures to some compounds present in coal and residuum were used as models. The active Ni catalyst was generatedin situby thermal decomposition of organic nickel complexes, all of which were active for hydrogenation of the models selected except for nickel naphthenate. The active Ni promoted ring saturation in aromatic and heteroatomic compounds rather than ring hydrogenolysis or heteroatom removal. In the presence of either elemental sulfur or organic sulfur compounds, the catalytic activity of Ni for hydrogenation and heteroatom removal was eliminated. Because of the high sulfur content in coal and residuum, inherent catalytic activity from the nickel indigenous to residuum for hydrogenation and heteroatom removal reactions during coprocessing may be hindered.

ISSN:0884-3759    

DOI:10.1080/08843759108942263

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor