生物质热解液化生物质油的试验研究

该研究利用闪速热解液化技术将木屑转化为易储存、易运输、易处理、能量密度高的液体产品生物质油,对旋转锥式闪速热解液化系统进行了生物质热解液化生物质油的试验研究,并将生产的生物质油进行了常压精馏和减压精馏试验,用色谱质谱分析仪、核磁共振仪对其部分精馏组分进行了成分分析。     

生物质热解固体热载体高温烟气加热装置设计与试验

固体热载体加热生物质是生物质热解制取生物油的工艺手段之一。为解决固体热载体间接加热方式升温慢、效率低问题,设计了一种流化床生物质燃烧的热烟气直接加热固体热载体装置,分析了其结构与原理,开展了固体热载体升温性能和流化床燃烧器的燃烧特性试验研究,并对试验结果进行了热平衡分析。结果表明:流化床高温烟气加热陶瓷球热载体的平均热能利用率为66.3%,流化床燃烧生物质粉产生的高温烟气能够满足热载体加热装置对热源的需求,热载体加热器内的热量传递方式主要是对流换热。陶瓷球热载体与加热器内高温烟气的对流传热系数为475 W/(m~2·℃)。研究对结果对解决生物质热解液化技术中的固体热载体加热升温关键问题具有重要指导意义。     

农林废弃物热解的试验研究

介绍了用于生物质热解的试验装置及试验方法，研究了温度、加热速率等因素对木屑、稻壳等农林废弃物生物质热解产物的产率及其质量的影响。试验结果表明，两种不同生物质热解产物得率的变化规律基本一致。热解温度控制在４００～５００℃时，热解油产率最大。热解温度越高，则炭产量越少；温度大于５００℃时，热解气为中等热值可燃气，其热值大于１０ＭＪ／ｍ^３。测试结果还表明，常规热解条件下的生物质热解表现为三阶段反应特点     

HPB-Ⅰ型生物质成型机的试验研究

对ＨＰＢ-Ⅰ型生物质成型机的成型参数、结构参数及生物质含水率作了成型试验研究,分析了成型压强与套筒的磨损及其影响因素。提出了通过合理调整成型温度和成型周期,选择合适的成型锥角和锥长能有效地降低成型机的单位产品能耗,延长易损件的使用寿命。为成型机的研制和应用提供了新的方法和依据。     

HPB—I型生物质成型机的试验研究

对ＨＰＢ－Ｉ型生物质成型机的成型参数,结构参数及生物质含水率作了成型试验研究,分析了成型压强与套筒的磨损及其影响因素,提出了通过合理调整成型温度和成型周期,选择合适的成型锥角和锥长能有效地降低成型机的单位产品能耗,延长易损件的使用寿命,为成型机的研制和应用提供了新的方法和依据。     

玉米芯和桉木的低温热解特性

为实现生物质资源的分级综合利用,该文采用热重分析仪和裂解气质联用仪进行了对玉米芯和桉木低温热解特性的研究。试验结果表明不同生物质原料低温快速热解产物有明显差异,玉米芯的低温快速热解产物主要有乙酸、2,3-二氢-苯并呋喃和2-甲氧基-4-乙烯基苯酚,而桉木的产物主要是乙酸、糠醛和5,6-二氢-4-羟基-吡喃-2-酮。生物质低温快速热解产物种类较少,分布较为集中,玉米芯和桉木的酸类、呋喃类,桉木的吡喃类热解产物相对含量随温度上升而降低。生物质低温热解能有效分解其半纤维素,这为降低中温热解油的酸性和水分提供了理论指导。     

生物质热解影响因素及技术研究进展

热解技术是实现农业生物质废弃物清洁利用的有效途径之一。该文概述了热解技术在农作物秸秆资源化利用中的应用,梳理介绍了生物质热解基本反应与过程和技术发展现状,探讨了制约生物质热解技术发展的主要问题,提出了开发低成本、高效率多技术集成的外热式回转窑热解炭化技术的方法。结合该团队在的技术积累,针对玉米秸秆热解炭化技术需求,通过集成密封进料、连续热解、热解气/油回燃等技术,开发了连续热解炭化联产技术装备,并建成了500 kg/h热解炭气联产示范工程,验证了新工艺的可行性和先进性,展现了良好的技术应用前景,解决了连续热解设备作业稳定性差、换热效率低等问题,实现了北方地区秸秆资源化综合利用,对提高农业综合效益、改善农村生活品质具有重要意义。在前期研究结果的基础上,提出进一步深入研究定向调控热解产物的方法,为实现农村生物质多联产轻简化系统提供理论指导。     

活性炭催化生物质与低密度聚乙烯共热解

为探究生物质主要组分与聚烯烃塑料在活性炭共催化热解过程的相互作用机理,该研究采用磷酸活化法制备了活性炭催化剂,利用固定床反应器对纤维素、木聚糖、木质素、花旗松单独催化热解及其与低密度聚乙烯共催化热解产物的产率及组成进行了分析。结果表明,活性炭催化纤维素和木聚糖单独热解的主要产物为呋喃类物质,其质量分数分别为78.6%和83.2%;而活性炭催化木质素热解的主要产物为简单酚类物质（86.6%）。与理论计算值相比,四种混合物共催化热解所得液体产率降低了8.7%～11.4%,气体产率提高了22.6%～64.0%;液体产物中芳烃和轻质脂肪烃（C9～C16）的质量分数增加而氧化物的质量分数降低;气体产物中H2的体积分数有所增加而CO和CO2的体积分数明显降低。活性炭催化剂作用下,生物质三组分与低密度聚乙烯之间相互作用的影响程度有所不同。     

稻壳热解模型建立与应用

生物质连续热解工艺是适合工业化生产的高效、合理的处理方式,该文基于稻壳在升温速率为20～40?℃/min,反应终温为800℃的热分析试验数据,建立了稻壳热解过程的分段反应模型并获得了反应动力学参数,其中失水预热解阶段满足N阶反应,主热解阶段满足J-M-A方程。对所建模型在建模升温速率范围内、外进行了检验,发现模型计算结果与试验数据相近,模型计算误差不大于2.35%,说明模型具有较广泛的适用性,为热解反应器的设计提供了理论依据。根据稻壳常规热解下失水预热解和主热解反应过程的模型计算结果,设计了变螺距生物质连续热解反应器,并以稻壳粉末为原料进行了参数试验,结果表明,该反应装置能实现连续、稳定热解,但由于实际升温不是理论上的线性升温过程,导致连续热解试验结果与模型计算结果和热重试验结果间存在一定差异。     

坚果壳类生物质慢速热解动力学分析

为研究坚果壳生物质的慢速热解动力学过程，对两类坚果壳类生物质(花生壳和葵花瓜子壳)进行了低升温速率下惰性气氛的热重分析实验。采用竞争型热解反应动力学模型描述它们的热解过程。在原有动力学机理函数的基础上，提出了一种新的经验动力学机理函数。利用现代优化技术——模式搜索法，对实验数据进行了动力学分析，结果表明：新动力学机理函数能有效描述坚果壳类生物质的慢速热解动力学过程。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.