摘要:

Deterioration in fuel quality upon storage has been a continuing problem in the utilization of middle distillate fuels. For diesel fuels. Instability is usually defined by the formation of insoluble sediments and gums and by the accumulation of hydroperoxides. Gravimetric accelerated storage stability tests conducted with model compounds as dopants in otherwise stable distillate fuels have demonstrated that oxidative condensation reactions of polar heterocylces are deleterious to stability. In particular, nitrogen containing aromatics (pyrroles, pyridinea, indoles, etc.) appear to be very harmful. Correlation of model dopant studies with results obtained with actual unstable fuels has indicated that autoxidation processes are usually not isolated reactions but are sensitive to the presence of other fuel constituents. In an effort to learn more about potential interactive effects, we have examined the autoxidation of two model compounds, 2, 5-dimethylpyrrole and 3-methylindole, in a shale diesel fuel in the presence of a second model dopant (a hydroperoxide, organic acid or base). The results presented support the notion that such interactive effects may be of critical importance in defining the stability of actual middle distillate fuels.

ISSN:0884-3759    

DOI:10.1080/08843758608915789

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

One-inch blocks of oil shale were treated under three different reaction conditions at 400°C to determine the kinds and amounts of organic materials recoverable. Extractions with liquid and combined liquid-supercritical solvent were found to be effective methods of recovering organic material from shale. Supercritical fluid extraction with methanol-water was found to be more effective than distillation-liquid flow mechanisms; however, large amounts of oil remained in the shale. Low-molecular-weight non-polar compounds were found to be the materials most easily recovered from shale while high-molecular-weight polar compounds were found to be the most difficult materials to recover.

ISSN:0884-3759    

DOI:10.1080/08843758608915790

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The relaxation time behavior for three macerals (vitrinite, fusinite, and resinite) of a subbituminous coal has been extensively characterized by13C solid state nor. Parameters studied included free radical concentrations.13C spin-lattice relaxation, T1C, cross polar1zation times, TCH, proton rotating frame spin-lattice relaxation. T1PH. dipolar dephasing times. T21, aromaticity, fa, and the effects of spinning sideband suppression on fa,. Large chemical shift variations among these samples were observed and assigned to various possible structural entities. Correlations between proximate and ultimate analyses and the nmr results, as well as comparisons with previously reported relaxation times are made.

ISSN:0884-3759    

DOI:10.1080/08843758608915791

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A liquid we derived from coal, and a liquid produced from Exxon donor solvent (EDS) vacuum gas oil served to stabilize coal particle suspensions. In one case the liquids were used like commercial stabilization additives for coal-petroleum oil mixtures (COMs) with poorer but comparable results. In the other case the idea of using the coal liquid itself as the suspending medium (in place of petroleum oil) was considered, with encouraging results.

ISSN:0884-3759    

DOI:10.1080/08843758608915792

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A shale fuel of marginal stability has been used as a source of nitrogen-rich polar extracts. Polar compounds were isolated by mild acid extraction followed by silica gel adsorption and were identified by GC/HS. Alkyl substituted pyridines were the prevalent class of compounds present in most extracts. The effects of adding these shale derived fractions as dopants to a stable shale diesel fuel (0-11) were examined in terms of sediment formation and peroxide number under accelerated storage stability test conditions. The activities of the extracts in inducing fuel instability were correlated with their composition.

ISSN:0884-3759    

DOI:10.1080/08843758608915793

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor