氧化锆负载型活性炭催化水解COS和CS_2

以椰壳活性炭为载体,采用浸渍法制备ZrO_2负载型活性炭催化剂,利用BET,XRD,XPS等手段对催化剂进行表征,考察了ZrO_2负载量、焙烧温度、相对湿度、氧含量、反应温度、气态空速等因素对催化剂催化水解COS和CS_2的影响。表征结果显示,反应后生成的硫和硫酸盐沉积在活性炭上,堵塞了活性炭的微孔,毒化了活性中心,从而使水解转化率下降。实验结果表明,w(Zr O2)=5.0%、焙烧温度500℃条件下制备的催化剂,在反应温度60℃、相对湿度19%、氧含量为1.0%(φ)、气态空速5 000 h-1、COS质量浓度1.6 mg/L、CS2质量浓度0.1 mg/L时具有较高的同时水解COS和CS_2的活性;COS和CS_2同时水解转化率最高,100%转化率分别持续630 min和570 min。     

广州造纸有限公司“十五”期间5．33万公顷造纸林基地发展规划

介绍了广州造纸有限公司“十五”期间造纸林基地建设的总体规划,包括地点选择,发展模式等,对基地出材量,投资效益作了预测;提出了基地投资资金的筹集方式。     

含机浆系统中铝离子对湿部化学特性影响的研究

含机浆系统是新闻纸、低定量涂布纸等印刷纸种常用的造纸系统。在酸性含机浆系统中AI2（SO4）3是最主要的添加物,但它对其他阳离子助剂有一定的影响。文国从纸浆对铝离子的吸附以及电荷分析和测量等方面研究了AI2（SO4）3对造纸湿部化学特性的影响,提出了AI2（SO4）3用量的严格界限。     

Large wood aids spawning Chinook salmon (Oncorhynchus tshawytscha) in marginal habitat on a regulated river in California

To determine whether large wood (LW, ≥1‐m length, ≥10‐cm diameter) plays a role in Chinook salmon (Oncorhynchus tshawytscha) redd (i.e. egg nest) placements in a regulated, Mediterranean‐climate, medium‐sized river (where channel width is less than the upper quartile of length of potential instream wood pieces), characteristics of 527 large wood pieces, locations of 650 redds, and mesohabitat delineations (riffle, run, glide, pool) were collected during a spawning season along a 7.7 km reach directly below Camanche Dam on the Mokelumne River, CA. LW was regularly distributed across the study reach an average 70 LW pieces km^‐1. Some LW clustering was evident at islands and meander bends. Spawners built 85% of redds within one average channel width (31 m) of LW. Spawners utilized LW within a 10 m radius 36% of the time in the upper 3 km rehabilitated reach, and 44% of the time in the lower 4.7 km marginal habitat reach. A greater percentage of LW was utilized in riffles in the upper 3 km reach where 90% of redds were built, while a larger percentage of spawners used LW in riffles in the lower 4.7 km reach. LW‐redd interactions occurred at greater rates than by random chance alone in the lower 4.7 km reach, which implies that LW aids spawning in marginal habitats. River managers and salmonid spawning habitat rehabilitation (SHR) projects should take LW additions into consideration as an important component of river rehabilitation. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of impregnation phases on the performance of Ni-based anodes for low temperature solid oxide fuel cells

Impregnated nanoparticles are very effective in improving the electrochemical performance of solid oxide fuel cell (SOFC) anodes possibly due to the extension of reaction sites and/or the enhancement of catalytic activity. In this work, samaria-doped ceria (SDC), pure ceria, samaria, and alumina oxides impregnated Ni-based anodes are fabricated to compare the site extending and the catalytic effects. Except for alumina, the impregnation of the other three nano-sized oxides could substantially enhance the performance of the anodes for the hydrogen oxidation reactions. Moreover, single cells with CeO₂ and Sm₂O₃ impregnated anodes could exhibit as great performance as those with SDC impregnated anodes. When the impregnation loading reached the optimal value, 1.7 mmol cm⁻³, these cells exhibit very high performance, with peak power densities around 750 mW cm⁻². The high performance of CeO₂ and Sm₂O₃ impregnated anodes demonstrates that the improved performance are mainly attributed to the significantly improved electrochemical activities of the anodes, but not to the extension of triple-phase-boundary, and wet impregnation is indeed an alternative and effective technique to introduce these nano-sized catalytic active oxides into the anode configuration of SOFCs to enhance cell performance, stability and reliability.     

Characterisation of the torrefaction of beech wood using NIRS: Combined effects of temperature and duration

A new approach is proposed to retrace the combined effects of temperature and duration within the thickness of heat-treated Fagus sylvatica wood. Torrefaction is a mild pre-treatment of biomass carried out at 200-300 °C to improve its properties for pulverized systems such as gasification. The properties of wood treated at high temperature are closely related to chemical modifications induced by temperature levels and treatment duration. This study involved the spectral analysis of solid wood in the near infrared range with the aim of developing a predictive model for process assessment. Samples of beech wood were used for calibration under high temperature conditions of 220, 250 and 280 °C for 1 and 8 h. For prediction, a 50-mm thick solid piece of wood was treated at 250 °C for 3 h. It was demonstrated that it is possible not only to distinguish between wood samples that have undergone different heat treatments, but also to retrace the thermal history of a piece of wood. Statistical processing showed the compensatory effects of temperature and duration, along with the existence of an exothermal reaction in the solid piece of wood. It should thus be possible to ensure cheaper and faster quality control in continuous torrefaction processes.     

Quantification of the residual biomass obtained from pruning of vineyards in Mediterranean area

This research quantified the available residual biomass obtained from pruning vines stock. The additional biomass quantified could be used as a source of energy or as raw material for the wood industry and would provide additional income for fruit producers and also a more sustainable system. Several factors were analyzed: Variety, aim of the pruning, age of the plants, size of the plantation, crop yield and irrigation. Regression models were also calculated to predict the weight of dry biomass, obtained per tree and tonnes of dry biomass obtained per hectare, according to the significant factors. These equations could implement logistic planning as the Borvemar model, which defines a logistics network for supplying bio-energy systems. The results show that the shape of the structure of plantation has a strong influence on the quantity of biomass produced, and therefore on the quantity of pruning material. In the vineyards cultivated for fresh grape production, the horizontal trellis produces 3.5 kg/tree and 4.2 t/ha, the more dry matter per vine tree than the double of the high trellis, and the triple than the standard trellis. In the vineyards cultivated for wine production, the standard trellis and vase shape do not have significant differences, reaching 0.8 kg dry matter per vine tree. Nevertheless, on the other hand, the standard trellis produces 2.15 t/ha, a 25% more dry biomass per hectare than the vase shape. The presence of irrigation increases biomass in vineyards by 42%.     

Enhanced electrochemical performance of solution impregnated La0.8Sr0.2Co0.8Ni0.2O3−δ cathode for intermediate temperature solid oxide fuel cells

Solution impregnated La_0.8Sr_0.2Co_0.8Ni_0.2O₃ + Gd-doped CeO₂ (LSCN + GDC) cathodes for intermediate temperature solid oxide fuel cells (IT-SOFC) are prepared and their electrochemical properties are evaluated and compared with the conventional LSCN cathodes. The results indicate that the cathode performance can be enhanced by the presence of the nanosized microstructure produced with the solution impregnation method. It is determined that the amount of LSCN loading in the LSCN + GDC composite cathode needs to be higher than 35 wt% in order to achieve a performance superior to that of the conventional LSCN cathode. The optimum amount of LSCN loading is in the range of 45-55 wt% with an activation energy near 1.32 eV for oxygen reduction. At temperatures between 600 and 750 °C, the polarization resistance of the 55 wt% LSCN loaded LSCN + GDC cathode is in the range of 1.07 and 0.08 Ω cm², which is only about one half of that for the conventional cathode.     

室内火灾条件下木材点燃的判据研究

在室内火灾中,木材是最为常见的可燃物,因此室内火灾条件下木材点燃问题的研究引起了广泛关注.建立了室内火灾热烟气和挥发份的填充模型,对热烟气层的稳定高度和木材点燃时的可燃挥发份临界质量通量进行了理论推导;在此基础上,对不同条件下木材的点燃进行了小规模实验研究,对点燃判据的有效性进行了验证.理论分析结果和实验研究结果具有较...     

NPAC技术降低柴油机NOx和碳烟排放的试验研究

利用等体积溶液浸渍法制备一种CeO2-CuO/γ-Al2O3负载型催化剂,应用X衍射分析仪(XRD)、电镜扫描仪(SEM)等表面分析技术对催化剂进行了表征,考察了该催化剂的性能.设计了一种低温等离子体(NTP)发生器,并建立了低温等离子体辅助催化(NPAC)试验系统.通过台架试验研究了NPAC技术对柴油机有害排放的作用规律,探索了排放物浓度、流量、滞留时间等因素对有害排放转化效果的影响.研究结果表明:NPAC技术可以有效降低柴油机碳烟排放,NOx排放明显降低;在NPAC作用下,碳烟转化效率最高接近60%.标定转速工况下,Ce02-CuO/γ-A1203催化剂活性较好,NOx排放转化率最高,在中高负荷工况下,转速越高对应的NOx转化效率越低.