摘要:

A high-performance liquid chromatography method was developed to determine the amount of each of the compound classes (such as saturates, aromatics and polars) in the oil fraction (pentane soluble fraction) of coal liquids. The method utilizes bonded cyanosilane and aminocyanosilane columns and mixtures of benzene inn-hexane and tetrahydrofuran in methyltert-butyl ether as mobile phases. A Tracor LC-rotating disc flame ionization detector was used to quantify the chromatographic peaks.

ISSN:0884-3759    

DOI:10.1080/08843758908962228

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Detrimental changes in fuel properties with time have been a continuing problem in the use of middle distillate fuels. Instability of diesel fuels is usually defined by the formation of insoluble sediments and gums. Gravimetric stability tests have been conducted at 43° and 80°C, respectively, using three model nitrogen heterocycles, 2-methylpyridine, 2,6-di methyl quinoline, and dodecahydrocarbazole, as dopants in an otherwise stable shale diesel fuel. Potential interactive effects have been defined for these three model nitrogen heterocycles in the stable fuel in the presence of a second model dopant, t-butyl hydroperoxide. 2-Methyl pyridine and 2,6-dimethyl quinoline were inactive and only 2-methyl pyridine showed slight positive interactive effects. Dodecahydro-carbazole formed large amounts of insolubles by itself and exhibited positive interactive effects.

ISSN:0884-3759    

DOI:10.1080/08843758908962229

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The hydrogenatlon and pyrolysls behaviour of solvent-refined coal (SRC) and base-free SRC have been investigated in the presence and absence of clay minerals and alumina-modified clay minerals. The yields of chloroform-soluble and insoluble products (coke) and aromaticities of chloroform-insoluble products have been measured to elucidate the mechanisms of these processes. The yield of chloroform-soluble products was greater after pyrolysis under molecular hydrogen than under molecular nitrogen, even though there was no decrease in the aromaticity of the products in either case. Hence hydrogen can assist in the formation of chloroform-soluble products without aryl ring hydrogenation. Higher yields of chloroform-soluble products were obtained with base-free SRC than with SRC but little or no effect of mineral matter was observed. It is suggested that SRC bases play an important and direct role in promotingin situcoking reactions apart from their well-established role in blocking acidic cracking sites.

ISSN:0884-3759    

DOI:10.1080/08843758908962230

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Two petroleum residua were studied, one of Mid-Eastern original and the other of Chinese origin. These residua were separated into fractions using preparative size-exclusion chromatography (SEC). Room temperature electron spin resonance (ESR) experiments of SEC separated petroleum-derived fractions are described. A variation of free radical concentration with different molecular weight fractions was observed. Significant increase in free radical concentration was observed in the 1000-2500 amu range. This is in the molecular weight range postulated to be necessary for formation of the mesophase state observed in carbonaceous pitches during conversion to coke and carbon by thermal treatment.

ISSN:0884-3759    

DOI:10.1080/08843758908962231

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Uapcur pressure csmometry (UPO) and viscometric technique were used to reveal the true molecular weight of asphaltenes and the degree of association in solvent of different polarities at different temperatures. The number average malecular weight of unassociated asphaltenes was found to be 935 g/mcl. In n' trobenzene at 120 C. The degrees of association were determined from UPO in benzene at 37, 45, 60 C, in chlorobunzene at 37, 45, 60 and 90 C. in THE at 37, 45, 60 C and in nitrobenzene at 90 C. The degree of association determined by ulscometric method at 37, 45 and 60 C, in these soluents were found to be in approximate agrement with that found bv UPO. Data derived by means of ulscometric and osmometric methods consolidated the recognition that asphaltenes could be similar to macro-molecules structurally.

ISSN:0884-3759    

DOI:10.1080/08843758908962232

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The calculations of the dispersion γCdand nondispersion (polar γCpcomponents of surface free energy of coal on the basis of adsorption measurements of nonpolar (n-heptane) and polar (methanol, propanol, water) liquid vapours a 20°C are presented. Average values ( γCd= 45.1 mJ/m2and γCp= 13.2 mJ/m2) are in good agreement with literature data calculated on the basis of separate and independent measurements. The heterogeneous nature of coal surface has been confirmed from derivatographic measurements.

ISSN:0884-3759    

DOI:10.1080/08843758908962233

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0884-3759    

DOI:10.1080/08843758908962227

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor