抽水蓄能机组静止变频起动技术

抽水蓄能机组在水泵运行方式下,同步发电机作为同步电动机在变频控制下起动主要有3个难点:发电机转子初始相位及低频运行时转子相位检测;根据转子所在的位置给相应绕组施加电流,并以正确方向旋转;发电机在低频运行阶段的断流换相问题。经过试验,找到了解决上述问题的方法,且控制简单可靠。     

考虑相关性的间歇性分布式电源选址定容规划

节能减排背景下,以分布式风电和光伏为代表的间歇性分布式电源得到了快速发展。考虑风速、光照强度和负荷间的相关性,以年综合费最小为目标,利用机会约束规划方法建立了间歇性分布式电源选址定容规划模型。采用秩相关系数矩阵表征风速、光照强度和负荷间的相关性,利用拉丁超立方采样和Cholesky分解生成相关性样本矩阵。应用动态小生境差分进化算法对规划模型进行求解。IEEE 33节点配电网算例的仿真结果验证了模型的合理性。     

间歇式电源并网系统的中长期特性仿真研究

间歇式电源的大规模发展及并网运行,在带来巨大经济效益的同时,也给电网中长期过程的频率稳定和有功平衡带来了巨大的影响。在间歇式电源机电暂态模型的基础上,对风电、光伏中长期自动发电控制(automatic generation control,AGC)子站进行建模,该模型可以接受调控中心AGC总站的调度命令,对间歇式电源进行功率调节。然后,利用甘肃电网的某典型日负荷、风速及光照曲线,深入分析了间歇式电源的波动特性及风光互补特性,验证了上述模型具有模拟中长期频率波动的能力。在此基础上,以平抑间歇式电源带来的联络线功率波动为目标,对机组出力计划、二次调频系统等控制策略的效果进行了分析。最后通过仿真计算论证了机组出力计划和AGC系统具有平抑间歇式电源功率波动性的作用。     

Urban net-zero water treatment and mineralization: Experiments,modeling and design

Water and wastewater treatment and conveyance account for approximately 4% of US electric consumption, with 80% used for conveyance. Net zero water (NZW) buildings would alleviate demands for a portion of this energy, for water, and for the treatment of drinking water for pesticides and toxic chemical releases in source water. However, domestic wastewater contains nitrogen loads much greater than urban/suburban ecosystems can typically absorb. The purpose of this work was to identify a first design of a denitrifying urban NZW treatment process, operating at ambient temperature and pressure and circum-neutral pH, and providing mineralization of pharmaceuticals (not easily regulated in terms of environmental half-life), based on laboratory tests and mass balance and kinetic modeling. The proposed treatment process is comprised of membrane bioreactor, iron-mediated aeration (IMA, reported previously), vacuum ultrafiltration, and peroxone advanced oxidation, with minor rainwater make-up and H₂O₂ disinfection residual. Similar to biological systems, minerals accumulate subject to precipitative removal by IMA, salt-free treatment, and minor dilution. Based on laboratory and modeling results, the system can produce potable water with moderate mineral content from commingled domestic wastewater and 10–20% rainwater make-up, under ambient conditions at individual buildings, while denitrifying and reducing chemical oxygen demand to below detection (<3 mg/L). While economics appear competitive, further development and study of steady-state concentrations and sludge management options are needed.     

Aeration and gutter water levels in siphonic roof drainage systems

An investigation is presented into how negative system pressures, the degree of aeration, and gutter water levels are affected by the number of outlets in a siphonic roof drainage system. The experimental results show that system pressures decrease if outlets are blocked. It is also shown that the depth of water above an outlet is strongly influenced by the negative pressure acting at the outlet. As the suction effect at the outlet increases, due to lower system pressures, more water and air will be drawn into the outlets and this will result in a corresponding increase in overall gutter water depth. The results also show that there is often built-in redundancy in multiple outlet siphonic systems experiencing lower-intensity rainfall events, and if one or two outlets were blocked, the system would still operate satisfactorily. A new outlet suppressor was trialled and this was shown to reduce gutter water levels by up to 58% at some positions in the gutter.

Il est présenté une enquête sur la manière dont les pressions négatives dans le système concerné, le degré d'aération et les niveaux d'eau dans les chéneaux sont affectés par le nombre d'orifices de sortie dans un système d'écoulement des eaux de toit par siphonnage. Les résultats expérimentaux montrent que les pressions dans le système diminuent si des orifices de sortie sont obturés. Il est également montré que la profondeur de l'eau au-dessus d'un orifice de sortie est fortement influencée par la pression négative s'exerçant à l'orifice de sortie. Plus l'effet de succion à l'orifice de sortie augmente, en raison des pressions plus faibles dans le système, et plus les quantités d'air et d'eau entraînées dans les orifices de sortie seront importantes, et cela aura pour résultat une augmentation correspondante de la profondeur générale de l'eau dans les chéneaux. Les résultats montrent également qu'il existe souvent une redondance intégrée dans les systèmes à siphons comportant des orifices de sortie multiples et soumis à des épisodes pluvieux de faible intensité, et que si un ou deux orifices de sortie sont obturés, le système fonctionne encore de manière satisfaisante. Un nouvel obturateur d'orifice de sortie a été essayé, ce qui a permis de montrer que celui-ci réduit dans une proportion allant jusqu'à 58 % en certains points les niveaux d'eau dans les chéneaux.

Mots clés: aération, niveaux d'eau dans les chéneaux, pressions négatives, écoulement des eaux de toit par siphonnage     

间歇式循环上向流污泥床的同步脱氮除磷研究

为了提高对城市污水的处理能力,介绍一种新型高效生化反应工艺——间歇式循环上向流污泥床.采用其处理实际生活污水,研究了其同步脱氮除磷效果.在进水COD为240～330 mg/L、TN为50～70 mg/L、TP为4.0～6.5 mg/L、DO为0.4 mg/L的条件下,该反应器能同时实现对COD、氨氮、SS、TN和TP的去除,出水澄清,SS含量很低,对COD、氨氮、总磷的去除率分别在90％、90％、82％以上,COD、BOD5、氨氮、TN浓度等均能达到一级A标准,TP浓度能达到二级标准.     

Effects of three conventional drying methods on the lipid oxidation,fatty acids composition,and antioxidant activities of walnut (Juglans regia L.)

Three walnut (Juglans regia L.) drying methods (sun drying, direct oven drying, and intermittent oven drying) were employed, and the consequent changes in lipid oxidation attributes, such as acid value (AV), peroxide value (POV), saponification value (SV), fatty acid composition, and antioxidant activity [including reducing power, superoxide anion scavenging activity, 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity (DPPH), lipoxygenase (LOX) activity, total phenols content (TPC), and total flavonoids content (TFC)] were investigated in this study. Sun drying resulted in the highest AV, POV, and SV, followed by direct oven drying and intermittent oven drying. Antioxidant activities and related compounds, TPC and TFC, were initially increased and then declined during drying, and a significant correlation was found between antioxidant activity and TPC and TFC. The LOX activities of all samples showed an increasing trend, although those of the sun-dried samples were the lowest. The walnuts dried with the intermittent oven drying method contained more linoleic acid than those dried by direct oven drying. Overall, intermittent oven drying appears to be a promising strategy for fresh walnut drying.     

Gas‐liquid mass transfer behavior in a surface‐aerated vessel stirred by a novel long‐short blades agitator

For a recently developed long‐short blades (LSB) agitator, its critical rotational speed for the onset of gas entrainment, power number, and gas‐liquid mass transfer behavior in the case of surface aeration is investigated. The effect of the LSB configurations and the liquid level on the agitator performance has been studied in details. The obtained results clearly show several advantages of the LSB agitator in gas‐liquid mass transfer with respect to the agitators in the literature. It is found that its gas‐liquid volumetric mass‐transfer coefficient at a given specific power can be several times larger than those shown in the literature. It can also avoid decrease in the gas‐liquid mass transfer rate as the liquid level increases. In addition, the bubble distribution in the system is more uniform with respect to conventional agitators, resulting from better distribution of the dissipated energy for the LSB agitator. © 2015 American Institute of Chemical Engineers AIChE J, 62: 1322–1330, 2016     

水下曝气对水体分层效果的研究

针对分层湖泊或水库底部因溶解氧不足而引起的水质恶化等问题,将水下曝气技术应用到水体分层破坏工程中。在实验水池中,展开了曝气流量、曝气孔径大小和曝气时长对水体分层破坏的实验研究,测量了曝气开始后不同时刻,水下1 m,2 m和2.3 m处水体中溶解氧含量,其中,曝气头垂直方向位于水下2 m处,水平方向上位于该矩形的中心位置。分析了曝气参数和曝气时长与水体分层破坏程度之间的关系。研究结果表明:曝气流量越大,水体分层破坏越快;曝气孔板直径越小,水体分层破坏越快。随着曝气流量的增加,水体中溶解氧的增量并不随之增加;随着曝气孔板孔径的减少,水体中溶解氧的增量逐步增加。同时,曝气头以下水体的溶解氧浓度与曝气无关。该研究结果为工程实际中的曝气法改善水体分层提供了依据。     

细胞焦亡介导慢性间歇缺氧大鼠肾脏损伤及依达拉奉的干预作用

目的：探究依达拉奉对慢性间歇缺氧导致大鼠肾脏损伤的保护作用及其对Caspase-1介导的细胞焦亡信号通路的影响。方法：24只SPF级雄性SD大鼠随机分为正常对照（NC）组、间歇缺氧（IH）组、间歇缺氧+生理盐水（IH+NS）组、间歇缺氧+依达拉奉（IH+EDA）组,每组6只。将4组大鼠放置在密闭式饲养舱内造模,NC组舱内氧气浓度维持在21%左右,IH组、IH+NS组、IH+EDA组定时输入纯氧气、纯氮气、压缩空气,使舱内形成缺氧-复氧循环（60 s低氧期+60 s复氧期）,低氧期舱内氧浓度降至6%～7%,每日造模8 h（10∶00-18∶00）,同时IH+EDA组大鼠每天造模前按照5 mg/kg剂量标准予以腹腔注射依达拉奉,IH+NS组大鼠按照同等剂量标准腹腔注射生理盐水。造模8周后采集大鼠血液标本及肾脏组织标本,测定各组大鼠血肌酐（Crea）、尿素（Urea）水平;HE、Masson染色后光镜下观察肾脏病理形态变化、纤维化程度;化学法测定丙二醛（MDA）含量、超氧化物歧化酶（SOD）活力;免疫组织化学染色法测定肾组织NLRP3、Caspase-1、IL-1β蛋白表达水平;Western blot法测定肾组织Caspase-1、IL-1β蛋白表达水平;RT-PCR法测定消皮素D（gasdermin D, GSDMD）、IL-18 mRNA扩增水平。结果：间歇缺氧暴露后,大鼠血清Crea、Urea明显升高（P<0.01）,肾小管发生病理损害、肾单位球囊间隙出现胶原纤维沉积,MDA含量增加、SOD活力降低（P<0.01）,Caspase-1、NLRP3、IL-1β蛋白表达增加（P<0.01或P<0.05）、GSDMD mRNA、IL-18 mRNA扩增增加（P<0.01）;而经过依达拉奉干预后,上述指标呈现出与间歇低氧暴露后相反的变化趋势,肾脏病理损害减轻（P<0.01或P<0.05）。 结论：慢性间歇缺氧可能通过氧化应激活化Caspase-1参与的细胞焦亡信号通路介导肾脏损伤过程,而依达拉奉可能通过清除氧自由基、下调机体氧化应激水平,抑制焦亡通路的活化,起到保护肾脏的作用。