摘要:

This article describes the extraction of coal raw material with an homologous series of low molecular mass alcohols in the supercritical state. The extraction system used was projected and built in the Institute of Chemistry of Sao Carlos. Because the system has low cost and is easy to handle, it presented very good results. The extraction yields obtained with the alcohols ranged from 32 to 46 %, the highest yield was obtained with ethanol. Supercritical fluid extraction showed to be an efficient extraction technique, and the use of ethanol has several advantages since it is a relatively low toxicity solvent, of low cost, and abundant in Brazil. Chromatographic and spectroscopic techniques were used to characterize the extracted materials.

ISSN:0090-8312    

DOI:10.1080/00908319950014687

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

This article presents a new dual purpose technique to improve photovoltaic (PV) array efficiency and has a great effect for the net power saving. To realize the first aim, the forced-air cooling technique with the optimal flow rate for PV array is designed and implemented. The decreasing rate in cell temperature has a direct proportional relation with PV efficiency. At the same time, the output hot air is very useful for air conditioning houses and for heating water systems, especially in remote areas. The electrical performance of PV modules also was studied. Finally, the effect of power saving was cleared and the economical results were achieved.

ISSN:0090-8312    

DOI:10.1080/00908319950014696

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

The level of hydrocarbon (HC) emissions, from a spark-ignition engine using a 30 % iso-butanol-gasoline blend was experimentally investigated. Experiments were conducted on a Hydra single-cylinder, spark-ignition, fuel-injection engine. HC emissions were measured as a function of fuel air equivalence ratio, ignition timing and engine speed. The effect of varying the temperature of cooling water on HC emissions was also investigated under three fuel air equivalence ratios (lean, stoichiometric, and rich). Results show that retarding ignition timing with respect to maximum break torque (MBT) has a great effect on HC emissions reduction, where for lean mixture, Phi 0.85, retarding ignition timing by 6 degrees from MBT reduces the exhaust HC emissions by 12 %. The level of HC emissions is also reduced by 30 % at MBT, as the cooling water temperature increase from 55 to 90 C. It is noticed that as the engine speed increases, the level of HC emissions decrease.

ISSN:0090-8312    

DOI:10.1080/00908319950014704

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

This article summarizes the technical characteristics of a biomass pyrolysis pilot plant recently constructed in central Greece. It highlights the considerations involved in achieving successful pyrolysis technology and environmental and developmental goals, by reviewing technical and nontechnical barriers associated with biomass treatment technology in Greece. Data from the start-up phase of the plant operation are presented and some aspects of the process are outlined. The capacity of the plant is 1200 1450 kg hr, based on wet biomass (Arbutus Unedo) and the pyrolysis temperature is approximately 400 C. Char yield is 14 18 % weight on dry basis and is of good quality consisting of 76 % C with heat content 6760 kcal kg. Bio-oil includes 63 % C and its heat content is 6250 kcal kg.

ISSN:0090-8312    

DOI:10.1080/00908319950014713

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

This article presents a review of the present energy situation, technical potential of renewable energy resources, future policies in the energy sector, energy conservation studies in residential, industrial, transport, and power sectors, and the efficient utilization of energy in Turkey. Some useful suggestions and recommendations are also presented. The present study shows that there is an important potential for renewable energy sources (biomass, hydropower, and solar) and energy saving capacity in Turkey.

ISSN:0090-8312    

DOI:10.1080/00908319950014722

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Peat, plant matter that is partially fossilized, is formed in poorly oxygenated wetlands where the rate at which the plant matter accumulates is greater than the rate at which it decomposes. Peat is a common solid fuel ranked among coal, coke, wood, and sugarcane bagasse. Peat has also been used to recover oil during the soil and water remediation processes. However, industrial utilization of peat in thermochemi cal conversion systems to liberate energy requires the knowledge of its thermal characteristics. In this study, the thermal behavior of peat (both uncontaminated and dieselcontaminated) was examined at three heating rates (10, 20, and 50 C min) in a stationary air atmosphere using a thermogravimetric analysis technique between ambient temperature (25C)and 600 C. The thermal degradation rate in active and passive pyrolysis zones, the initial degradation temperature, and the residual weight at 600 C were determined. Increasing the heating rate increased both the thermal degradation rate and the residual weight at 600 C and decreased the initial degradation temperature. The residual weight at 600 C was less than the ash content in all of the peat samples indicating the burnout of some of the mineral oxides, which have low melting and boiling temperatures, such as K2O and P2O. The results provide useful information about utilization of diesel-contaminated peat in thermochemical conversion systems, especially gasifiers, because of its high energy content and low ash content.

ISSN:0090-8312    

DOI:10.1080/00908319950014731

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Peat, plant matter that is partially fossilized, is formed in poorly oxygenated wetlands where the rate at which the plant matter accumulates is greater than the rate at which it decomposes. Peat is a common solid fuel ranking among coal, coke, wood, and sugarcane bagasse. It has also been used to recover oil during the remediation processes of contaminated water and soil. Because of its high moisture content, peat has a high potential as biofuel material for gasification. However, proper understand ing of the physical and thermochemical properties of peat is necessary for the design of thermochemical conversion systems. This study provides information on moisture content, bulk density, particle size, heating values, proximate analysis, ultimate analysis, ash composition, and ash fusibility characteristics of uncontaminated and diesel-contaminated peat. The moisture content of uncontaminated peat was 7.10 % , whereas that of diesel-contaminated peat ranged from 8.65 % to 10.80 %. The bulk density for the uncontaminated peat was 151 kg m3, which increased to 391-534 kg m3 due to diesel contamination. Most of the particles (60%) were in the form of dust. The results also showed an ash content of 3.23 % and the lower heating value of 17.65 MJ kg (dry weight basis) for the uncontaminated peat. The ash content decreased substantially, whereas the lower heating value increased due to diesel contamination. The ash fusion temperature of the peat was found to be over 1100 C.

ISSN:0090-8312    

DOI:10.1080/00908319950014740

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Of the various energy conversion options of rice husk, thermochemical conversion processes such as pyrolysis, combustion, and gasification offer the most efficient way to use rice husk. However, a knowledge of the thermal characteristics of rice husks is essential for the optimal design of these systems and for ensuring stringent emissions as well as high conversion efficiency. Thermogravimetric analysis is used to profile weight loss due to physical and chemical phenomena taking place in the sample while being subjected to high temperatures. This technique presents an ideal system to study thermal properties of carbonaceous materials. Evaluation of the thermogravimetric behavior of four rice husk varieties (Lemont, ROK 14, CP 4, and Pa Potho) at three heating rates (10, 20, and 50 C min) in an oxygen atmosphere is described. The thermal degradation rates, the initial degradation temperature, and the residual weight at 700 C were deter mined. These thermal degradation indices of rice husks are a function of tempera ture, heating rate, and the composition of the rice husks. The initial degradation temperature decreased while both the thermal degradation rate and the residual weight at 700 C increased when the heating rate was increased. The higher the cellulosic content of the rice husk, the higher the thermal degradation rate and the initial degradation temperature. Also, higher ash content in the rice husk resulted in higher residual weight at 700 C. Rice husk could be degraded to the extent of 73-80 %.

ISSN:0090-8312    

DOI:10.1080/00908319950014759

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

The reduction in CO2 emissions by photoelectrochemical conversion of the CO2 to formic acid and methanol using silicate rock (andesite) powders suspended in water is presented. For photoelectrochemical reduction of CO2, a homemade cell with a platinum and a copper electrode was used. 0.1 M KHCO3 solution was used as the electrolyte. In the photoelectrochemical reduction of CO2 with a copper cathode in the catholyte dispersing andesite powder, mainly formic acid, methanol, methane, ethylene, carbon monoxide, and hydrogen were produced. Consequently, it was found that this method using a copper electrode was effective for formic acid and methanol formations from carbon dioxide.

ISSN:0090-8312    

DOI:10.1080/00908319950014768

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor