摘要:

A pilot-scale continuous-flow no-mix reactor of 25 L capacity was designed to act as a liquid-solid separator in order to maximize the generation and retention of biomass. The system was used to study the effects of operating temperature, solid content, and hydraulic retention time on the biogas yield and pollution potential reduction of dairy manure. The system has a higher biogas production rate than other systems reported in the literature operating under similar conditions. Reductions of up to 58.15, 55.90, and 48.43% in the solids, chemical oxygen demand, and nitrogen concentrations were achieved in the effluent. The sludge obtained from the system had high nitrogen and ash concentrations and can be used as a fertilizer concentrate or as a protein supplement in animal feeding.

ISSN:0090-8312    

DOI:10.1080/00908319208908714

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Die de-asphalting of vacuum residue of Nigerian medium-gravity crude with nitrobenzene has been studied. Analytical data such as viscosity index, viscosity gravity constant, and molecular weight were used to characterize the residue, while chromatographic analyses of the solvent-free extract and raffinate products provided a measure of nitrobenzene de-asphalting efficiency at different solvent-residue ratios. From these data, it was established that the residue was paraffinic and suitable for lube oil manufacture. At a solvent-residue ratio of 6, a de-asphalted oil yield of more than 70 wt. % was achieved, which is comparable to those often reported for the conventional propane system at relatively higher solvent proportions. In contrast to the observed trend of solubilization power, the selectivity of nitrobenzene toward asphaltic material showed a decrease with increased solvent proportion, resulting in the more desirable raffinate with potentially improved oil composition at lower solvent-residue ratio.

ISSN:0090-8312    

DOI:10.1080/00908319208908715

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Highly mineralized waters with salt content up to 200 kg/m3occur in carboniferous strata in upper Silesia. These waters often contain high226Ra concentration, reaching 400 kBq/m3, and flow from the surrounding rocks into mine workings and then have to be pumped out to the surface, finally ending in the rivers. Radium-bearing waters of type A contain significant amounts of barium ions. In these cases radium is easily co-precipitated with barium in the form of BaSO4+ RaSO4. The specific radioactivity of such deposits can be as high as 1 MBqlkg. Radioactive deposits cause elevated gamma radiation levels up to 200 pA/kg and also some elevation of radon daughter concentrations in air. Usually the contamination is limited to small areas lying near streambeds where radium-bearing waters have flowed. Nevertheless, waste materials from coal mines may cause significant radioactive pollution of the natural environment. In carboniferous strata, so-called radium-bearing waters of type B occur. These waters contain considerable amounts of sulfates but do not contain Ba2+ions. In type B waters the concentration of226Ra reaches 12 kBq/m3. In this case there are no chemical conditions for forming highly radioactive deposits.

ISSN:0090-8312    

DOI:10.1080/00908319208908716

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The growing demand for diesel fuel relative to fuel oil has caused refiners to increase conversion of fluid catalytic cracking (FCC) operation. This has increased production of diesel blending components, such as cracked middle distillates, which have poorer storage stability, cetane index, and fuel quality. On the other hand, diesel specifications are expected to decrease the sulfur and aromatic levels to 0.05 wt. % and 10-20 liquid volume%, respectively. Economic evaluation of alternatives to meet diesel specifications showed hydrotreating to be the most feasible. Recent studies have shown that available hydrotreating technologies need further development in catalysts and processes to meet this challenge. This paper reviews the scientific and technical literature regarding the hydrotreating of middle distillate in terms of economics, chemistry, processes, and catalysts, and proposes a new direction in technology development.

ISSN:0090-8312    

DOI:10.1080/00908319208908717

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Experimental data are reported on the extents and rates of removal of impurities from a low-grade, low-rank South Australia lignite by thermal treatment of coal-water slurries in the temperature range 250-3S0“C, Removal of up to 80% of the water, 50% of the oxygen, 40% of the organic sulfur. 60% of the sodium chloride, and 30% of the “ash” constituents has been achieved, with a coal product yield of about 80% (dry, mineral-matter-free basis), containing over 98% of the original coal energy. Process thermal efficiency is estimated to be ∼95%. A distributed activation energy model provides a satisfactory fit to experimental data for the evolution of volatile species.

ISSN:0090-8312    

DOI:10.1080/00908319208908718

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Petroleum resource assessment begins with geological study of sedimentary basins and subdivision of the sedimentary sequence and petroleum prospects into plays. Next, information about the plays, the area and geometry of their traps, and the sizes of their accumulations are compiled in a database within the AUSTPLAY program. Some data are sorted, plotted, and analyzed by the program. All data are examined by specialist geoscientists, who interpret the historic trends, select analogues, make quantitative models, and use subjective judgment to determine the information to be used in the assessment.

ISSN:0090-8312    

DOI:10.1080/00908319208908719

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

No account of the current or future use of geothermal energy within New Zealand would be complete without an overview of the far-reaching political and organizational changes that have taken place over the past 3 years within the electricity supply industry. This paper briefly reviews these changes and outlines their possible impact on the future utilization of geothermal energy in the country.

ISSN:0090-8312    

DOI:10.1080/00908319208908720

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0090-8312    

DOI:10.1080/00908319208908721

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0090-8312    

DOI:10.1080/00908319208956241

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0090-8312    

DOI:10.1080/00908319208956243

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor