A new biomass-gasification power plant, of medium-size downdraft type, is presented and discussed in its design features and performance characteristics. Its configuration and overall dimensions, initially conceived f...A new biomass-gasification power plant, of medium-size downdraft type, is presented and discussed in its design features and performance characteristics. Its configuration and overall dimensions, initially conceived for 800 kW, were recently re-tuned, from a functional point of view and on the base of a parallel theoretical analysis, by decreasing to about 400 kW the former nominal power level. This provision, jointly with the basic design choice of adopting a long and amply dimensioned inlet-biomass thermal pretreatment section, turned out quite effective in achieving high gasification temperatures and a low-tar content in the produced gas at fuel-to-air ratios well below the usually imposed ones, to the advantage of the heat value of the product-gas. The paper discusses the numerical analysis results which helped to properly re-adjust the operational parameters of the gasifier and then presents the experimental performance data of the overall power plant including biomass consumption, gasification temperatures, gas production, composition and pollutants content, cold-gas conversion efficiency and global electric efficiency. Special care is devoted to investigating the issue of a significant production of carbon-containing particulate matter in the product gas, which turns out made up of char and fixed carbon much more than of tar species.展开更多
This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identif...This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identify the chemical compositions of the A. rnalaccensis leave-oil. By assessing both first-order kinetic model and the model of simultaneous washing and diffusion, the result indicated that the model of simultaneous washing and diffusion better describes the hydro-distillation mechanism of the essential oil from A. rnalaccensis leaves. The optimum time, solid to liquid ratio, and the heating power for extracting the highest amount of essential oil were found to be around 3 h, 1：10 （g. ml-1）, and 300 W respectively. Yellow essential oil with a strong smell and a yield of 0.05 v/w was extracted by hydro-distillation Clevenger apparatus. Chemical compounds of the essential oil were analyzed using gas chromatography-mass spectroscopy （GC/MS）, which resulted in identification of 42 compounds that constitute 93% of essential oil. Among the identified components, Pentadecanal （32.082%）, 9-Octadecenal, （Z） （15.894%）, and Tetradecanal （6.927%） were the major compounds. Considering the fact that all the identified major components possess pesticidal properties, A. malaccensis leaves can be regarded as a promising natural source for producing pesticides.展开更多
Two field trials were clone to evaluate the effects of plant density on the growth, development and yield of safflower. The results showed that plant density and season of growth had significant （P ≤ 0.01） effects ...Two field trials were clone to evaluate the effects of plant density on the growth, development and yield of safflower. The results showed that plant density and season of growth had significant （P ≤ 0.01） effects on growth, development, yield components, yield and oil content of safflower. Increasing safflower plant density from 100,000 to 250,000 plants ha^- significantly reduced plant height （13.2%-21.3%）, branch number plant^-1 （37%-54.7%）, leaf number plant^-1 （39%-39.2%）, leaf area （19.5%-53%）, plant spread （39.6%-54.4%）, root length （28.1%-54.4%）, plant biomass （17%-50%）, capitula size （12%-12.7%）, capitula number plant^-1 （39.5%-50.5%）, seed number capitula~ （39%-45%）, capitula weight （3.3%-3.6%）, seed yield （67.9%-69.8%） and seed oil content （14.7%-20.8%）. The reduction in vegetative growth, yield components, yield and oil content of safflower due to increased plant density was attributed to inter and intra-plant competition for light, nutrients and water necessary for growth and development. The differences between winter and summer grown safflower were attributed to difference in day and night temperature （DIF） and the average daily temperature which were optimum for safflower growth in winter. It was concluded that under Botswana conditions or in semi-arid areas, safflower should be planted at 50 cm × 20 cm or wider in order to maximize yield and oil content and allow the plants to express their maximum genetic potential.展开更多
文摘A new biomass-gasification power plant, of medium-size downdraft type, is presented and discussed in its design features and performance characteristics. Its configuration and overall dimensions, initially conceived for 800 kW, were recently re-tuned, from a functional point of view and on the base of a parallel theoretical analysis, by decreasing to about 400 kW the former nominal power level. This provision, jointly with the basic design choice of adopting a long and amply dimensioned inlet-biomass thermal pretreatment section, turned out quite effective in achieving high gasification temperatures and a low-tar content in the produced gas at fuel-to-air ratios well below the usually imposed ones, to the advantage of the heat value of the product-gas. The paper discusses the numerical analysis results which helped to properly re-adjust the operational parameters of the gasifier and then presents the experimental performance data of the overall power plant including biomass consumption, gasification temperatures, gas production, composition and pollutants content, cold-gas conversion efficiency and global electric efficiency. Special care is devoted to investigating the issue of a significant production of carbon-containing particulate matter in the product gas, which turns out made up of char and fixed carbon much more than of tar species.
文摘This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identify the chemical compositions of the A. rnalaccensis leave-oil. By assessing both first-order kinetic model and the model of simultaneous washing and diffusion, the result indicated that the model of simultaneous washing and diffusion better describes the hydro-distillation mechanism of the essential oil from A. rnalaccensis leaves. The optimum time, solid to liquid ratio, and the heating power for extracting the highest amount of essential oil were found to be around 3 h, 1：10 （g. ml-1）, and 300 W respectively. Yellow essential oil with a strong smell and a yield of 0.05 v/w was extracted by hydro-distillation Clevenger apparatus. Chemical compounds of the essential oil were analyzed using gas chromatography-mass spectroscopy （GC/MS）, which resulted in identification of 42 compounds that constitute 93% of essential oil. Among the identified components, Pentadecanal （32.082%）, 9-Octadecenal, （Z） （15.894%）, and Tetradecanal （6.927%） were the major compounds. Considering the fact that all the identified major components possess pesticidal properties, A. malaccensis leaves can be regarded as a promising natural source for producing pesticides.
文摘Two field trials were clone to evaluate the effects of plant density on the growth, development and yield of safflower. The results showed that plant density and season of growth had significant （P ≤ 0.01） effects on growth, development, yield components, yield and oil content of safflower. Increasing safflower plant density from 100,000 to 250,000 plants ha^- significantly reduced plant height （13.2%-21.3%）, branch number plant^-1 （37%-54.7%）, leaf number plant^-1 （39%-39.2%）, leaf area （19.5%-53%）, plant spread （39.6%-54.4%）, root length （28.1%-54.4%）, plant biomass （17%-50%）, capitula size （12%-12.7%）, capitula number plant^-1 （39.5%-50.5%）, seed number capitula~ （39%-45%）, capitula weight （3.3%-3.6%）, seed yield （67.9%-69.8%） and seed oil content （14.7%-20.8%）. The reduction in vegetative growth, yield components, yield and oil content of safflower due to increased plant density was attributed to inter and intra-plant competition for light, nutrients and water necessary for growth and development. The differences between winter and summer grown safflower were attributed to difference in day and night temperature （DIF） and the average daily temperature which were optimum for safflower growth in winter. It was concluded that under Botswana conditions or in semi-arid areas, safflower should be planted at 50 cm × 20 cm or wider in order to maximize yield and oil content and allow the plants to express their maximum genetic potential.
