摘要:

Four Chinese 350°C+ reduced crude feedstocks were heated thermally in the presence of a contact material at 480–540°C in a fixed bed reactor. The feed and products were fractionated into eight fractions using normal pentane precipitation and alumina adsorption chromatography and average molecular parameters calculated with a modified Brown-Ladner method. The results obtained show that the conversion of various fractions of the reduced crudes was quite different. The conversion of asphaltic substances was much higher than those of saturates and aromatics. It is shown that the CH2/CH3ratio, aromaticity and the numbers of aromatic, naphthenic and total ring of heavy products were obviously lower than those of reduced crudes. The effect of temperature on metal, sulfur, nitrogen removal has been also investigated. The data indicate that the removal of weak polar non-porphyrin nickel was larger than that of middle and strong polar nickel complex.

ISSN:0884-3759    

DOI:10.1080/08843759108942264

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Using a combination of instrumental and chemical methods many new classes of compounds appearing as homologous series have been detected in Athabasca oil sand bitumen and in the chemical and thermal degradative products of asphaltene and the heavy ends of maltene. In general, the volatile portion of the maltene is rich in cyclic terpenoid structures and devoid in aliphatic compounds ornormalalkane-derived cyclic molecules while the asphaltene fraction and heavy ends of maltene are abundant innormalalkyl-substituted aromatics, thianes, thiolanes, thiophenes, benzo- and dibenzothiophenes

ISSN:0884-3759    

DOI:10.1080/08843759108942265

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Arabian Light crude oil vacuum bottoms has been fractionated into five high-boiling fractions by wiped film evaporation, and the fractions subjected to catalytic cracking in a fixed-fluidized bed using a commercial equilibrium cracking catalyst. Density, aromaticity, and heteroatom content generally increased with boiling point, as did metals content except for vanadium and iron which demonstrated possible bimodal distributions. The cracking response of these fractions showed increasing yields of dry gas and coke, with decreasing gasoline yields, as a function of increasing apparent boiling point as would normally be expected. Surprisingly, however, local maxima were observed for wet gas yield and total conversion, with local minima for cycle oil and slurry yields, in the region of the 1200–1263°F (650–680°C) middle fraction. All fractions showed significant response to cracking, with coke yields generally being the only negative factor observed.

ISSN:0884-3759    

DOI:10.1080/08843759108942266

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Catalyst life in residual oil hydrotreating is dependent on the deposition of coke and metals in the catalyst pores. Although silicon naturally occurs in relatively small amounts in crude oils, recent analysis in this laboratory of used catalyst from a commercial unit showed silicon deposits of one to six percent inside catalyst particles. Laboratory reactor tests simulating commercial operations showed that silicon deposition reduced both catalyst hydrodesulfurization and hydro-demetallization activity. Electron microprobe analysis demonstrated that silicon deposition influenced deposition profiles of metals, sulfur, and carbon.

ISSN:0884-3759    

DOI:10.1080/08843759108942267

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Oxidative pyroanalysis apparatus was settled to fully characterize heavy oils. Fractions distribution, and elemental composition were obtained in one single run on both volatile and non volatile fractions. Correlation between experimental Carbon residue values and Conradson carbon residue data is possible and a crackability index of the heaviest part of heavy oil is determined. From all gathered data, quality of products can be appreciated in these circumstances as well as thermal sensitivity resulting in accurate determination of conversion indices.

ISSN:0884-3759    

DOI:10.1080/08843759108942268

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Analytical studies have been performed on effluents issued from thermal conversion of Safaniya Vacuum residue (Arab Heavy) in presence of tetralin, thiophenol and methyldisulfide. In contrast to thermal behavior of the heavy oil alone, low coke amount was produced at high conversion level (up to 50%) beside good product qualities as demonstrated from analysis of the remained 500°C+fractions. H-donor diluent and sulfide additives help effectively in lowering the carbon residue values and maintaining the H/C ratios at the highest values compatible with the conversion. Microstructural parameters of the liquid effluents and their asphaltenic parts are obtained1H and13C NMR spectroscopy and average molecular weight determination. Even at high conversion level results allow to assess a rapid dealkylation process at the first stage of the thermal treatments associated with a good control in the evolution of the size of polyaromatic units. Optical Microscopy and X-ray analysis outline the specific effect of tetralin as a. delayed coking additive.

ISSN:0884-3759    

DOI:10.1080/08843759108942269

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A Spanish subbituminous coal was subjected to non-catalytic liquefaction with tetralin in a 250 ml stirred autoclave. The operating conditions used were: one hour reaction time, 17 MPa operating pressure and 400 r.p.m, stirring speed. The liquefaction products were fractionated into oils, asphaltenes, preasphaltenes and solid residue by a solvent extraction technique using pentane, toluene and THF as extractive solvents. It was found that the influence of temperature on coal liquefaction yields and product distributions varies with the amount of donatable hydrogen. Total coal conversion increases with temperature, when very high tetralin/coal ratios are used On the contrary, when 1/1 ratio is used, conversion does not seem to depend on temperature, and appears to be limited by the amount of liquid medium available as physical solvent. At intermediate tetralin/coal ratios,conversion generally increases with both factors: temperature and amount of solvent. However, retrogressive reactions are observed at 475°C which indicates that these reactions are produced at high temperatures when there is not enough hydrogen in the system

ISSN:0884-3759    

DOI:10.1080/08843759108942270

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

If the processability of heavy or residual oil is assessed in terms of conversion to distillate oils, the tendency to form carbonaceous (coke) deposits in the reactor would impose limits on the operating conditions, since any significant coke accumulation on a continuing basis would be prohibitive. Experimentally, one can evaluate the feedstock coking propensity in a bench-scale reactor for a set of typical hydroprocessing conditions by varying the temperature near the threshold of coking. For a number of different feedstocks examined by this method, an empirical function can be found correlating the coking propensity with some of the characteristic properties determined by routine analyses. The present approach used a combination of physical and chemical properties including density and contents of Conradson Carbon residue, pentane and toluene in-solubles, fraction of high-boiling pitch, and carbon, hydrogen, nitrogen, sulfur and ash. Feedstocks were chosen to cover a wide but practical range of properties to establish their impact on the coking propensity. Although these relationships apply to thermal hydroprocessing, the role of catalysts is also indicated.

ISSN:0884-3759    

DOI:10.1080/08843759108942271

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Mayan, Heavy Arabian, and Hondo crude oil resids have been separated with a modified, extended ASTM D2007 procedure. The fractions obtained have been characterized with various analytical techniques. Chemical properties, hydrodesulfurization, and hydrodemetallation activities of the resids have been correlated with the chemical properties of the separated fractions. Many correlations were indicative of the overall bulk properties of the resids and the broad chemical classes obtained from the separation schemes. Other correlations reflected the unique chemical nature of each crude oil resid. Some potentially important correlations were found between hydrodesulfurization activity and sulfur concentration in polars and asphaltenes, and between hydrodemetallation activity and nitrogen concentration in the acid and bases fractions.

ISSN:0884-3759    

DOI:10.1080/08843759108942272

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0884-3759    

DOI:10.1080/08843759108942273

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor