摘要:

Secondary Ion Mass Spectrometry (SIMS) has been used to examine the low-temperature oxidation of coal, using18O2and in conjunction with site-specific reagents in order to identify the surface distribution of oxygen functional groups. This approach leads to some ambiguity in the assignment of functional groups because the inherent complexity of coal chemistry rarely allows any definitive reaction products to be identified. This paper describes results obtained from reaction of coal surfaces with a sequence of reagents designed to remove ambiguous results. This procedure, coupled with SIMS imaging, yields results consistent with an oxidation mechanism which involves the formation of surface peroxides.

ISSN:0090-8312    

DOI:10.1080/00908318908908936

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

An important phenomenon in the physics of miscible displacement of hydrocarbon fluids in oil reservoirs is viscous fingering, or frontal instability. Simulators are the principal tools used by the reservoir engineers for predicting hydrocarbon recovery under various processes. The reliability of the simulators results is enhanced if they account for the effect of viscous fingering. In this paper we present an easy-to-use technique for that purpose, applicable for one-dimensional flow. The method basically calculates an effective viscosity and density for the displacing fluid. The technique was used in the simulator to model linear, miscible displacement experiments reported in the literature. The agreement between the experimental and calculated results was good.

ISSN:0090-8312    

DOI:10.1080/00908318908908937

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Data from an experimental study of coal-derived residuum reactivity are reported. Thermal conversion experiments were completed at short contact time reaction conditions using eight residuum samples derived from Kentucky 9114 and Illinois 6 bituminous coals. Results indicated that residuum reactivity toward distillate production decreased with increased severity of catalytic prehydrotreatment. Asphaltene disproportionate and retrogressive reactions to form insoluble organic matter were suppressed when the feed residuum was hydrotreated prior to thermal conversion. Results from elemental analysis and Fourier Transform Infrared spectroscopic measurements on selected asphaltene samples suggested that disproportionation occurred via a mechanism of phenolic condensation.

ISSN:0090-8312    

DOI:10.1080/00908318908908938

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Hydropower generation from the Qattara depression has been subject to thorough investigations during the last five decades. The general conclusion reached was that the project has rather low benefits in comparison with its cost. This was mainly attributed to the exorbitant cost of channeling sea water into the depression. In the latter juncture, it was found that using nuclear excavation would substantially reduce the expenses; however, such a solution was rejected on ecological grounds. The present approach to the project is aimed at escalating its benefits, by incorporating an integrated system of solar ponds for base load. In the present context, the heat extracted from the solar ponds is used to operate thermal power plants that will follow a novel cycle of the Rankine type. The new method arrived at will enable the simultaneous production of electricity and fresh water. Despite the fact that the combined hydro-solar arrangement leads to augmenting the benefits to cost ratio by at least 21%, when compared with the latest proposal of setting a conventional hydro-plant, the dual output of electricity and fresh water will furnish good grounds for the regional development of the Qattara area, which is quite desirable.

ISSN:0090-8312    

DOI:10.1080/00908318908908939

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This paper describes the efforts of the Electrochemistry Group of the Institute of Physics and Chemistry/USP to develop electrode materials for water electrolyzers and of components for phosphoric acid fuel cells. In the last few years, several fundamental studies have been carried out in the electrocatalysis of water electrolysis reactions, particularly on hydrogen evolution, which allowed the development of materials with lower overpotentials, compared with those of conventional cathodes. In the phosphoric acid fuel cell area, substantial progress has been made in the development of teflon-bonded gas diffusion electrodes, bipolar separator plates, and electrolyte-containing matrices. These components have been tested in 50 W and 200 W phosphoric acid fuel cell modules.

ISSN:0090-8312    

DOI:10.1080/00908318908908940

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Most of the huge amount (91 %) of energy in rural India is used as domestic fuel. Forest wood constitutes half of this energy, which could be saved by providing an alternative kitchen fuel. Biogas provides the only viable alternative. While the basics of biogas production have been known for several decades, serious research efforts are required to evolve appropriate technology of biogas production for Indian villages. It is easy to design devices which work on the economy of large scale; it is a formidable task to achieve the same at down-to-earth level of economy. Considering the vast majority of small farmers, a cheap, manual, continuous fermentation straw gas plant is likely to offer appropriate technology. Efforts have continued since 1965 to develop such a plant: The latest model is quite competitive in all respects with the KVIC biogas plant, except for its stirring system. Efforts are being made to develop a suitable stirring system.

ISSN:0090-8312    

DOI:10.1080/00908318908908941

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0090-8312    

DOI:10.1080/00908318908908942

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor