扁平类农业物料流化床分级与分离的特性

本文通过对打瓜籽,葵花籽,以及杏仁与杏壳等扁平类农业物料在流化床试验台架上进行的分级与分离试验,分析研究了影响流化床分级与分离效果的各个性能参数,并对流化床是按物料密度进行分级与分离的论点提出了看法。文中同时提出了增强扁平类农业物料流化床分级与分离效果的有效措施。     

液—液循环流化床液滴形成特性研究

基于图像采集与处理方法对液-液循环流化床液滴形成特性进行了实验研究,提出了形成液滴的3种液-液雾化方式,考察了液-液雾化方式与射流长度脉动、液滴粒径分布的相关性,获得了液-液雾化方式的转变规律以及雾化强度、射流长度脉动和液滴粒径分布基于相对雷诺数的变化规律.结果表明,雾化过程与相对雷诺数密切相关,随着相对雷诺数的增加,雾化强度持续增强,液-液雾化方式由滴流型向层流射流型转变,最后发展为湍流射流型;在整个相对雷诺数实验范围内,射流长度的脉动表现出随机和非周期的特点,其标准方差与平均值的变化规律基本一致,在相对雷诺数为1.3×104时达到最大值;液滴的粒径分布参数一直增大到湍流射流型雾化阶段,在相对雷诺数为2.5 ×104时,液滴的粒径均匀性最好,而液滴平均粒径总体上随相对雷诺数的增大不断减小,形成液滴的最小平均粒径发生在湍流射流型雾化阶段.     

Seagrass beds and mangroves as potential nurseries for the threatened Indo-Pacific humphead wrasse, Cheilinus undulatus and Caribbean rainbow parrotfish, Scarus guacamaia

The importance of seagrass beds and mangroves as a juvenile habitat as opposed to other shallow water habitat types is investigated using a single sampling method on four islands in the western Indian Ocean for Cheilinus undulatus, and on one island in the southern Caribbean Sea for Scarus guacamaia. Both species occur on the Red list of threatened species. Juveniles of Cheilinus undulatus were predominantly found on seagrass beds while adults were limited to the coral reef. The presence of seagrass beds resulted in significantly higher densities of the species on coral reefs in front of these habitats, indicating the importance of seagrass beds as a juvenile habitat. For Scarus guacamaia, juveniles were exclusively observed in mangroves while adults only occurred on the coral reef. Adult S. guacamaia occurred on all coral reefs along the sheltered coast of the island containing mangroves, but no relationship with distance to mangroves was observed. This could indicate the importance of mangroves for the occurrence of adults of this species on the scale of an entire island.     

116MW循环流化床锅炉房的电气优化设计

随着城镇供热的迅速发展,116MW循环流化床锅炉被普遍应用。本文从工程应用和规程规范出发,对116MW循环流化床锅炉房电气设计提出了优化设计方案。     

玉米秸秆循环流化床气化炉气化工艺参数优化

为实现秸秆类农业生物质废弃物的高效清洁能源化转化利用,采用带有二级返料系统的循环流化床气化炉对玉米秸秆进行了气化试验。在二级返料系统开启及闭合条件下,选取空气当量比为0.20～0.35,研究空气当量比对玉米秸秆气化特性的影响,结果表明二级返料系统开启及闭合两种工况均在空气当量比为0.26时取得较优值,二级返料系统开启时具有较好的气化效果,碳转化率与气化效率最大值分别达到93.54%与77.06%。在二级返料系统开启状态下,试验研究了水蒸气配比对玉米秸秆气化特性的影响,结果表明以空气为主气化介质,辅助以水蒸气气化,可以有效改善气化燃气品质,提升气化效率。当空气当量比为0.26、水蒸气配比为0.2时,玉米秸秆空气—水蒸气气化具有较好的气化特性,燃气热值与气化效率分别达到最大值5.89MJ/m3与81.45%。典型工况条件下的焦油蒸馏馏分分析结果表明,提高气化炉反应温度,并保持一定的水蒸气气化环境,可促进焦油裂解转化。试验可为秸秆类生物质的高效清洁转化利用提供参考依据。     

Periglacial transport distance of Pb derived from small-scale ore veins in the Rhenish Slate Mountains

The spatial extent of metal contamination caused by small-scale ore veins is increased by periglacial solifluction. Our objectives were (1) to examine the spatial distribution of Pb in cover beds that migrated over Pb ore veins, (2) to calculate the transport distance of ore-derived Pb, and (3) to determine controls on the transport distance.We examined six transects (320-775 m long) in the Rhenish Slate Mountains in West Germany. The transects included four west-exposed and two east-exposed slopes with inclinations between 2-20°. All transects were forest-covered and located at 280-450 m above sea level. Soils were Dystric Cambisols and Stagnic Luvisols. Samples of 120 B horizons developed in the sediments of the last ice age (Wuerm) were analyzed for total Pb concentrations and partly also ²⁰⁶Pb/²⁰⁷Pb ratios. The Pb concentrations ranged from 20 to 135 mg kg^− 1. The spatial Pb distribution suggested that 14 (out of 18) sampling points showing local Pb concentration maxima contained Pb from ore veins upslope. With a two-end-member-mixing model using ²⁰⁶Pb/²⁰⁷Pb isotope ratios of the ore (²⁰⁶Pb/²⁰⁷Pb ratio: 1.1828) as one end member and of the native substrate (a mixture of slate and loess; ²⁰⁶Pb/²⁰⁷Pb ratio: 1.2254 ± 0.0072) as the other we confirmed that the 14 Pb peaks originated from the ore, because they contained 76-100% of ore-derived Pb. By the use of a geographic information system, the transport distance of this Pb was determined to range between 30 and 110 m. Silt concentrations (Pearson r = − 0.69) and the relief curvature (Cramér's V = 0.60) were major controls on the transport distance. Our study demonstrates that Pb ore veins can increase native soil Pb concentrations in soil derived from the periglacial drift of the last ice age (Wuerm) up to a distance of more than 100 m.     

Mathematical Model of Flow Process in 40t/h Pyroflow Circulating Fluidized Bed Boiler

A mathematical model is presented to describe the fluiddynamics processes for the combustion system of 410t/h Pyroflow CFB boiler.A core annulus structure with solid dispersion from core to annulus is considered,and the influence of coal particles fragmentation,attrition and broad size distribution of feeding coal and bed inventory on hydrodynamics is specially taken into account.The simulation results show that the CFB boiler has good hydrodnamic characteristics and high hot cyclone efficiency.     

多孔高分子载体固定化微生物厌氧流化床处理低浓度废水的研究

本文报道用厌氧流化床反应器处理低浓度有机废水的可行性研究结果。采用多孔高分子载体固定厌氧微生物和流态化技术强化传质过程,可克服低浓度有机废水甲烷化能力低的障碍。实验表明,在３５±１℃条件下,处理ＣＯＤ浓度为１６００ｍｇ／Ｌ的人工葡萄糖废水,床层最优膨胀率为５０％,容积有机负荷率为１９．２ｇＣＯＤ／（Ｌ·ｄ）,ＣＯＤ去除率达７０％;处理ＣＯＤ浓度为２２０～２５０ｍｇ／Ｌ的城市污水,容积有机负荷率为２．４～２．６ｇＣＯＤ／（Ｌ·ｄ）,ＣＯＤ去除率为５４％～５６％。     

三种因素对海水生物流化床启动期间营养盐去除及amoA基因表达的影响

在实验室规模下,以旋转式生物流化床(CB-FSB)为研究对象,研究了初始总氨氮(TAN)、水温及滤料膨胀率3种条件下,海水生物流化床生物过滤功能启动期间TAN和亚硝酸盐氮(NO-2-N)去除及amoA基因数量的变化。结果显示:生物流化床生物过滤功能启动所需时间随着水温的升高而缩短,在水温为15℃、20℃和25℃时,启动所需时间分别为27 d、25 d和23 d;初始TAN质量浓度的升高也会缩短生物流化床生物过滤功能启动所需要的时间,在初始TAN质量浓度为1 mg/L、2 mg/L、4 mg/L时,启动所需时间分别为24 d、22 d和21 d;在膨胀率为100%和150%时,启动所需时间无明显差别,分别为21 d和20 d,明显好于膨胀率为50%时启动所需时间27 d;amoA基因的数量变化与TAN去除率的变化有一定的相关性,并随着初始TAN浓度的升高而增多,在4 mg/L时数量最多,达到2.76×10~7copies/g。     

流化床生物质快速热裂解试验及生物油分析

在自行研制的一套进料量为5 kg/h流化床上,选用高铝矾土为流化床床料,选择450℃、475℃、500℃和525℃ 四个反应温度对玉米秸秆粉的快速热裂解规律进行了研究,主要考察了不同反应温度对热裂解产物收集率的影响。在热解温度为500℃左右时,生物油收集率具有相对高的数值：37.5%。所得到生物油有两个分层,利用气相色谱－质谱联用仪对各自成分进行了定性分析。