野生水芹与旱芹的营养成分比较分析

为研究野生水芹的营养价值,以湖北野生水芹和旱芹为材料,对新鲜叶片和叶柄的主要营养成分进行了比较分析。结果表明:两种材料叶片和叶柄的淀粉、粗纤维和维生素B1含量的差异不明显,游离氨基酸和维生素B2含量比旱芹低,但野生水芹含有丰富的蛋白质和钙,其叶柄中可溶性糖和磷的含量分别达29.70 mg/g和0.77mg/g,分别比旱芹高57.23%和37.50%;其叶片维生素C、铁含量分别达0.19 mg/g和0.35 mg/g,比旱芹分别高137.50%和191.67%,整株黄酮类物质含量是旱芹含量的2倍。这说明野生水芹具有较高的食用价值,是一种适合作为涝渍地区保护性开发的野生蔬菜资源。     

Techno-economic evaluation of the integrated biosorption-pyrolysis technology for lead (Pb) recovery from aqueous solution

An integrated biosorption-pyrolysis technology was employed to recover Pb from aqueous solution. A series of biosorption, fast pyrolysis and leaching experiments were carried out. The optimum pH and adsorbent dose for Pb adsorption from aqueous solution are 6.0 and 3.0 g L⁻¹, respectively. The temperature is a key factor influencing the yields of pyrolysis products, and the maximum yield of bio-oil is 45.7% at 773 K. The pyrolysis technology can effectively recover Pb from Pb polluted Typha angustifolia biomass (Pb-TAB) and its recovery efficiency is not notably influenced by temperature. According to the economic evaluation, the biosorption-pyrolysis technology has great techno-economic advantages over the conventional biosorption-leaching technology.     

熔盐热裂解生物质制生物油

为探讨热裂解条件对熔盐中生物质热裂解制生物油的影响,在自行设计的反应器中,以摩尔比为7∶6的ZnCl2-KCl混合熔盐作为热裂解的热载体、催化剂和分散剂,考察了500 ℃时添加的金属盐和生物质原料的影响,并采用气相色谱-质谱仪 (GC-MS) 对生物油的主要组成进行了分析。结果表明：添加的金属盐显著影响热裂解产物得率,稀土金属盐显著提高生物油得率,降低生物油的含水率,添加摩尔分数为5.0％ LaCl3时生物油得率为32.0％,含水率为61.5％;水稻秸秆热裂解的生物油和焦炭得率较高,稻壳热裂解的气体得率较高;金属添加盐对生物油组成有较强的选择性,LiCl和FeCl2对生物质向小分子裂解具有较强的催化作用,而CrCl3、CaCl2和LaCl3对生物油二次裂解具有抑制作用。研究结果为熔盐热裂解生物质制生物油提供了参考。     

Microwave-assisted pyrolysis of microalgae for biofuel production

The pyrolysis of Chlorella sp. was carried out in a microwave oven with char as microwave reception enhancer. The results indicated that the maximum bio-oil yield of 28.6% was achieved under the microwave power of 750 W. The bio-oil properties were characterized with elemental, GC-MS, GPC, FTIR, and thermogravimetric analysis. The algal bio-oil had a density of 0.98 kg/L, a viscosity of 61.2 cSt, and a higher heating value (HHV) of 30.7 MJ/kg. The GC-MS results showed that the bio-oils were mainly composed of aliphatic hydrocarbons, aromatic hydrocarbons, phenols, long chain fatty acids and nitrogenated compounds, among which aliphatic and aromatic hydrocarbons (account for 22.18% of the total GC-MS spectrum area) are highly desirable compounds as those in crude oil, gasoline and diesel. The results in this study indicate that fast growing algae are a promising source of feedstock for advanced renewable fuel production via microwave-assisted pyrolysis (MAP).     

不同基因型水生植物对铵态氮和硝态氮吸收动力学特性研究

针对不同营养状况的富营养化水体修复而选择吸收养分效率较强的水生植物,采用改进常规耗竭法比较研究了6种不同基因型水生植物凤眼莲(Eichhornia crassipes Solms)、黄花水龙(Jussiaea stipulacea Ohwi)、再力花(Thalia dealbata Fraser)、美人蕉(Canna glauca L.)、水芹[Oenanthe javanica(Bl).DC]和豆瓣菜(Nasturtium officinaleR.Br.)对铵态氮和硝态氮吸收动力学特性。结果表明,不同基因型水生植物吸收铵态氮和硝态氮的动力学特性可用Michaelis-Menten方程来描述。在低浓度培养下,不同基因型水生植物对NH4+-N和NO3--N吸收的动力学参数Imax和Km差异较大,其吸收NH4+-N和NO3--N的Imax最大是水芹,其次是豆瓣菜;Km值最小的是水芹,其次是豆瓣菜;且水芹对NH4+-N和NO3--N不仅具有较强的亲和力,还具有较高的离子吸收速率。结果还表明,当介质中氮浓度较低时,水芹有优先吸收硝态氮的趋势,而豆瓣菜和再力花有优先吸收铵态氮的趋势。     

Crop Management Impacts Biofuel Quality: Influence of Switchgrass Harvest Time on Yield, Nitrogen and Ash of Fast Pyrolysis Products

Although upgrading bio-oil from fast pyrolysis of biomass is an attractive pathway for biofuel production, nitrogen (N) and mineral matter carried over from the feedstock to the bio-oil represents a serious contaminant in the process. Reducing the N and ash content of biomass feedstocks would improve process reliability and reduce production costs of pyrolytic biofuels. This study investigated: (1) How does switchgrass harvest date influence the yield, N concentration ([N]), and ash concentration of biomass and fast pyrolysis products? and (2) Is there a predictive relationship between [N] of switchgrass biomass and [N] of fast pyrolysis products? Switchgrass from five harvest dates and varying [N] from central Iowa were pyrolyzed using a free-fall reactor. Harvestable biomass peaked in August (8.6 Mg ha^?1), dropping significantly by November (6.7 Mg ha^?1, P?=?0.0027). Production of bio-oil per unit area mirrored that of harvested biomass at each harvest date; however, bio-oil yield per unit dry biomass increased from 46.6 % to 56.7 % during the season (P?=?0.0018). Allowing switchgrass to senesce lowered biomass [N] dramatically, by as much as 68 % from June to November (P?<?0.0001). Concurrently, bio-oil [N] declined from 0.51 % in June to 0.17 % by November (P?<?0.0001). Significant reductions in ash concentration were also observed in biomass and char. Finally, we show for the first time that the [N] of switchgrass biomass is a strong predictor of the [N] of bio-oil, char, and non-condensable gas with R ² values of 0.89, 0.94, and 0.88, respectively.     

Microwave induced pyrolysis of oil palm biomass

The purpose of this paper was to carry out microwave induced pyrolysis of oil palm biomass (shell and fibers) with the help of char as microwave absorber (MA). Rapid heating and yield of microwave pyrolysis products such as bio-oil, char, and gas was found to depend on the ratio of biomass to microwave absorber. Temperature profiles revealed the heating characteristics of the biomass materials which can rapidly heat-up to high temperature within seconds in presence of MA. Some characterization of pyrolysis products was also presented. The advantage of this technique includes substantial reduction in consumption of energy, time and cost in order to produce bio-oil from biomass materials. Large biomass particle size can be used directly in microwave heating, thus saving grinding as well as moisture removal cost. A synergistic effect was found in using MA with oil palm biomass.     

Fast Pyrolysis Behavior of Banagrass as a Function of Temperature and Volatiles Residence Time in a Fluidized Bed Reactor

A reactor was designed and commissioned to study the fast pyrolysis behavior of banagrass as a function of temperature and volatiles residence time. Four temperatures between 400 and 600°C were examined as well as four residence times between ~1.0 and 10 seconds. Pyrolysis product distributions of bio-oil, char and permanent gases were determined at each reaction condition. The elemental composition of the bio-oils and chars was also assessed. The greatest bio-oil yield was recorded when working at 450°C with a volatiles residence time of 1.4 s, ~37 wt% relative to the dry ash free feedstock (excluding pyrolysis water). The amounts of char (organic fraction) and permanent gases under these conditions are ~4 wt% and 8 wt% respectively. The bio-oil yield stated above is for ''dry'' bio-oil after rotary evaporation to remove solvent, which results in volatiles and pyrolysis water being removed from the bio-oil. The material removed during drying accounts for the remainder of the pyrolysis products. The ''dry'' bio-oil produced under these conditions contains ~56 wt% carbon which is ~40 wt% of the carbon present in the feedstock. The oxygen content of the 450°C, 1.4 s ''dry'' bio-oil is ~38 wt%, which accounts for ~33 wt% of the oxygen in the feedstock. At higher temperature or longer residence time less bio-oil and char is recovered and more gas and light volatiles are produced. Increasing the temperature has a more significant effect on product yields and composition than increasing the volatiles residence time. At 600°C and a volatiles residence time of 1.2 seconds the bio-oil yield is ~21 wt% of the daf feedstock, with a carbon content of 64 wt% of the bio-oil. The bio-oil yield from banagrass is significantly lower than from woody biomass or grasses such as switchgrass or miscanthus, but is similar to barley straw. The reason for the low bio-oil yield from banagrass is thought to be related to its high ash content (8.5 wt% dry basis) and high concentration of alkali and alkali earth metals (totaling ~2.8 wt% relative to the dry feedstock) which are catalytic and increase cracking reactions during pyrolysis.     

Fast pyrolysis of soybean cake: product yields and compositions

This study was an investigation of the role of important parameters influencing pyrolysis yields from soybean cake. Experiments were carried out at temperatures ranging from 400 to 700 degrees C, for various nitrogen flow rates, heating rates and particle sizes. The maximum liquid yield was 42.83% at a pyrolysis temperature of 550 degrees C with a sweeping gas rate of 200 cm3 min(-1) and heating rate of 700 degrees C min(-1) for a soybean cake sample having 0.425 < D(p) < 0.85 mm particle size. The various characteristics of liquid product were identified. Thus, the aliphatic sub-fraction of the bio-oil was analysed by GC-MS and further structural analyses of bio-oil and aromatic and polar sub-fractions were conducted using FT-IR and 1H-NMR. The H/C ratios and the structural analysis of the fractions obtained from the biocrudes showed that the fractions were quite similar to currently utilised transport fuels.     

The effects of different catalysts on the pyrolysis of industrial wastes (olive and hazelnut bagasse)

Pyrolysis of olive and hazelnut bagasse biomass samples with two selected catalysts, namely activated alumina and sodium feldspar, have been conducted in a fixed-bed reactor. Experiments were carried out under certain pyrolysis conditions in a fixed-bed Heinze reactor. The catalyst was mixed with feedstock in different percentages. The effects of catalysts and their ratio (10%, 20%, 30% and 40% w/w) on the pyrolysis product yields were investigated and the results were compared with the results of experiments performed without catalyst under the same conditions. The maximum bio-oil yields for the bio-oils obtained from pyrolysis of olive bagasse were found as 37.07% and 36.67% on using activated alumina and sodium feldspar as catalysts, respectively, while these values were 27.64% and 31.68%, respectively, for the bio-oils from hazelnut bagasse. The oxygen contents of the bio-oils were also markedly reduced while the yield of bio-oil was reduced by the use of catalysts. The pyrolysis oils were examined using some spectroscopic and chromatographic analysis techniques. The results were compared with the petroleum fractions and the possibility of being a potential source of bio-oils was investigated.     

野生水芹的合理开发利用

主要阐述了野生水芹的药用、食用价值及其急待开发的环保作用。随着人们生活水平的不断提高,野生水芹以其特有的集治病和健身于一体的功能被越来越多的人所喜爱。针对目前日渐严重的湿地污染,可以利用野生水芹其极强的生命力和较广的适应能力的特性,进行综合环境治理。     

Bio-oil and bio-char from low temperature pyrolysis of spent grains using activated alumina

The pyrolysis of wheat and barley spent grains resulting from bio-ethanol and beer production respectively was investigated at temperatures between 460 and 540 °C using an activated alumina bed. The results showed that the bio-oil yield and quality depend principally on the applied temperature where pyrolysis at 460 °C leaves a bio-oil with lower nitrogen content in comparison with the original spent grains and low oxygen content. The viscosity profile of the spent grains indicated that activated alumina could promote liquefaction and prevent charring of the structure between 400 and 460 °C. The biochar contains about 10-12% of original carbon and 13-20% of starting nitrogen resulting very attractive as a soil amendment and for carbon sequestration. Overall, value can be added to the spent grains opening a new market in bio-fuel production without the needs of external energy. The bio-oil from spent grains could meet about 9% of the renewable obligation in the UK.     

Production and characterization of pyrolysis liquids from sunflower-pressed bagasse

Pyrolysis experiments on sunflower (Helianthus annus L.)-pressed bagasse were performed in a fixed-bed tubular reactor. The effects of nitrogen flow rate and final pyrolysis temperature on the pyrolysis product yields and chemical compositions were investigated. The maximum bio-oil yield of 52.10 wt.% was obtained in a nitrogen atmosphere with flow rate of 50 ml min(-1) and at a pyrolysis temperature of 550 degrees C with a heating rate of 5 degrees C s(-1). The chemical characterization results showed that the oil obtained from sunflower-pressed bagasse may be a potentially valuable source as fuel or chemical feedstocks.     

空心莲子草对南京春季杂草群落组成和物种多样性的影响

空心莲子草(Alternanthera philoxeroides)是目前我国危害最为严重的外来植物之一。利用样方法调查了南京市春季有空心莲子草分布的不同生境下杂草的种类和分布情况,用主成分分析及聚类分析法进行数据处理分析,目的是研究空心莲子草对杂草群落组成和物种多样性的影响。结果表明,南京市春季有空心莲子草分布的样点杂草有36科142种,其中禾本科、菊科、蓼科最多;影响空心莲子草及伴生杂草分布、发生的主要因素是土壤水分条件和人为干扰强度。依据这两个因素的不同,可将样点划分为4个聚类群,比较了各聚类群物种多样性指数,结果显示:各聚类群里随着空心莲子草重要值的升高,Simpson优势度指数也逐步上升,表明空心莲子草的优势度得到加强;Shannon-Weiner指数和Pielou均匀度指数均逐渐下降,说明了群落的物种多样性持续降低,原来的优势种危害加大,空心莲子草的入侵影响群落结构,使物种多样性降低。     

Pyrolysis characteristics and kinetics of oak trees using thermogravimetric analyzer and micro-tubing reactor

In this work, pyrolysis characteristics were investigated using thermogravimetric analysis (TGA) at heating rates of 5-20 degrees C/min. Most of the materials were decomposed between 330 degrees C and 370 degrees C at each heating rate. The average activation energy was 236.2 kJ/mol when the pyrolytic conversion increased from 5% to 70%. The pyrolysis kinetics of oak trees was also investigated experimentally and mathematically. The experiments were carried out in a tubing reactor at a temperature range of 330-370 degrees C with a reaction time of 2-8 min. A lump model of combined series and parallel reactions for bio-oil and gas formation was proposed. The kinetic parameters were determined by nonlinear least-squares regression from the experimental data. It was found from the reaction kinetic constants that the predominant reaction pathway from the oak trees was to bio-oil formation rather than to gas formation at the investigated temperature range.     

Uptake and release of nutrients by living and decomposing Typha glauca godr. tissues at Eagle Lake,Iowa

Uptake and release of nitrogen, phosphorus, potassium, calcium, and sodium from living above-ground and below-ground tissues and from decomposing litter of Typha glauca Godr. were studied at Eagle Lake, IA, during 1976. All nutrients were accumulated rapidly by shoots in the spring. Some of the nitrogen and phosphorus came from belowground storage; but potassium, calcium, and sodium were extracted entirely from the soil. Nutrients were immobilized in shoot tissues for different periods of time. Potassium content declined as rapidly as it had accumulated, and there was no evidence of belowground storage. Nitrogen and phosphorus content also declined, though not as rapidly. Approximately 45% of the nitrogen and phosphorus lost from the shoots was translocated to the rhizomes and stored. Calcium and sodium were conserved in shoot tissues until the shoots died. In the decomposing litter, potassium and sodium content declined, phosphorus and calcium content remained relatively constant, but nitrogen content increased. Over the full year of production and decomposition, this Typha glauca stand accumulated calcium and nitrogen, maintained phosphorus levels, and lost potassium and sodium.     

Co-pyrolysis of walnut shell and tar sand in a fixed-bed reactor

This study investigated potential synergistic activities between tar sand and walnut shell during co-pyrolysis. A series of pyrolysis studies were conducted under specific operating conditions in a fixed-bed reactor. The highest yield of bio-oil from the co-pyrolysis was 31.84 wt.%, which represented an increase of 7.88 wt.% compared to the bio-oil yield from the pyrolysis of walnut shell alone. The bio-oils were characterized using various spectroscopic and chromatographic analysis techniques. The results indicated that the synergetic effect increased the co-pyrolysis bio-oil yield and its quality. Consequently, the results indicate that the bio-oils obtained will be suitable for the production of fuels and chemicals as feedstock after required improvements.     

Effects of Pyrolysis Temperature on Product Yields and Energy Recovery from Co-Feeding of Cotton Gin Trash,Cow Manure,and Microalgae: A Simulation Study

The intensive search of new and cleaner energy catches interest in recent years due to huge consumption of fossil fuels coupled with the challenge of energy and environmental sustainability. Production of renewable and environmentally benign energy from locally available raw materials is coming in the frontline. In this work, conversion of the combined biomass (cotton gin trash, cow manure, and Microalgae [Nannochloropsis oculata]) through batch pyrolysis has been investigated. The effect of temperature to the production of energy fuels such as bio-oil, char, and biogas have been simulated considering the yield and energy content as responses. Result of the investigation generally revealed that the proportions of the different biomass did not significantly affect the product yield and energy recovery. Significant effect of temperature is evident in the simulation result of energy recovery whereby maximum conversion was achieved at 400°C for char (91 wt%), 600°C for syngas (22 wt%), and 551°C for bio-oil (48 wt%). Overall energy conversion efficiency of 75.5% was obtained at 589°C in which 15.6 MJ/kg of mixed biomass will be elevated to pyrolysis products.     

Depth distribution of three Typha species, Typha orientalis Presl, Typha angustifolia L. and Typha latifolia L., in an artificial pond

The depth distribution of the aquatic macrophyte Typha orientalis Presl was examined in comparison with two other Typha species: Typha angustifolia L. and Typha latifolia L. Vegetation surveys mapping the depth distributions were conducted at Ushigafuchi Pond, Tokyo, Japan, in autumn 2004 and 2005. All vegetation had been cleared from this artificial pond in spring 2003. In 2004 T. orientalis was distributed in shallow to deep water habitats between T. latifolia (shallow water regions) and T. angustifolia (shallow to deep water regions). However, by 2005 T. orientalis had almost disappeared from the pond. It had been replaced by Leersia japonica Makino at depths of 0–30 cm, by Schoenoplectus validus (Vahl) at depths of 30–60 cm and by T. angustifolia at depths of 60–100 cm. It appears that T. orientalis is not a strong competitor, particularly with taller species, but rather a pioneer species.     

Microwave pyrolysis of distillers dried grain with solubles (DDGS) for biofuel production

Microwave pyrolysis of distillers dried grain with solubles (DDGS) was investigated to determine the effects of pyrolytic conditions on the yields of bio-oil, syngas, and biochar. Pyrolysis process variables included reaction temperature, time, and power input. Microwave pyrolysis of DDGS was analyzed using response surface methodology to find out the effect of process variables on the biofuel (bio-oil and syngas) conversion yield and establish prediction models. Bio-oil recovery was in the range of 26.5-50.3 wt.% of the biomass. Biochar yields were 23.5-62.2% depending on the pyrolysis conditions. The energy content of DDGS bio-oils was 28 MJ/kg obtained at the 650 °C and 8 min, which was about 66.7% of the heating value of gasoline. GC/MS analysis indicated that the biooil contained a series of important and useful chemical compounds: aliphatic and aromatic hydrocarbons. At least 13% of DDGS bio-oil was the same hydrocarbon compounds found in regular unleaded gasoline.