MBR与NF联用净化微污染水源水研究

对纳滤膜在不同产水率条件下的净水性能和膜通量衰减过程,以及纳滤膜在产水率90％条件下的运行特性进行了分析.采用MBR作为预处理与纳滤膜联用,考察联用工艺对水中氨氮和有机物的去除效果,以及MBR膜和纳滤膜的污染情况.结果表明,相比于额定工况,纳滤膜在90％产水率条件下运行,对有机物的去除率和脱盐率分别降低4％和3.5％,仍具有优越的净水性能;膜通量衰减速度增加17％.研究同时表明,降低纳滤膜进水中有机物的浓度能够有效缓解纳滤膜的污染过程,使纳滤膜能够在90％产水率条件下保持较高的通量.MBR与纳滤膜联用对氨氮和TOC表现出良好的去除效果,在进水浓度为1.5 mg/L、3.5 mg/L时,出水分别降低到0.4 mg/L、0.2 mg/L.MBR通过去除水中的颗粒物和有机物,有效地缓解了纳滤膜的污染过程,在60天的运行中纳滤膜通量仅下降24.7％,但MBR膜TMP增长较快,试验中共进行了6次膜清洗.     

用振动剪切波强化工艺处理洗毛废水的试验研究

采用振动剪切波强化工艺(VSEP)和选用DS-5纳滤膜处理洗毛废水.结果表明,在操作压力1.4MPa、运行温度45～50℃,设备振幅12.7mm(1/2英寸)的条件下,在废水总固体浓度为37800～144000mg/L浓度范围内时,膜水通量为94.4～34.6L/(m2·h).对洗毛废水中COD、羊毛油脂和总固体TS的一次性去除率分别为98.5%,99.7%和94%.膜的清洗周期为5天左右,清洗后膜水通量恢复至膜初始水通量水平的90%以上.     

膜法染料废水处理工艺研究

用乙酸纤维素纳滤膜 ,对染料厂的高盐度、高色度、高CODCr染料废水的处理操作条件 (进料量、压力 )、浓缩过程 (染料含量、浓缩倍率 )、膜的污染和清洗等方面进行了详细研究 .结果表明 ,用纳滤膜技术处理染料废水时 ,过程的通量随着进料流量和操作压力的升高而增大 ,并随着浓缩过程的进行即染料含量和浓缩倍率的增加而下降 ,但仍对染料保持很高的截留率 ,且在高染料浓度 (高浓缩倍率 )下 ,压力对通量影响下降 :在过程回收率达到 80 %(浓缩 5倍 )的情况下 ,膜对废水中色度和CODCr的去除率仍相当高 ;有效的膜清洗则可提高纳滤膜处理染料废水过程的效率 ,延长膜使用寿命 ,从而使纳滤膜法染料废水处理工艺技术更具实用价值 .     

国产纳滤膜淡化高氟苦咸水基础研究

实验选取两种国产纳滤膜NF2A和NF3A进行纳滤膜淡化高氟苦咸水的基础研究,考察操作压力、温度、进水pH、进水氟浓度、总含盐量(TDS)及运行时间对纳滤膜分离性能的影响,并测定膜的Zeta电位,同时简单比较两种膜.研究结果表明,两种纳滤膜处理高氟苦咸水的理想操作条件为:压力1.0～1.5 MPa,温度20℃,进水pH=6.5左右,在此条件下NF3A纳滤膜的脱盐率为79％,脱氟率为90％,产水通量为53 L/(m2·h),NF2A纳滤膜的脱盐率分别为73％,73％和71L/(m2·h),此外,随进水氟浓度和总含盐量的增大,纳滤膜的脱氟和脱盐率降低,同时得出两种膜在长期运行72 h内膜性能基本保持稳定,最后测得NF3A和NF2A的Zeta电位分别为-22和-18 mV.这项研究为国产纳滤膜处理高氟苦咸水的实际应用提供了技术数据,有利于国产纳滤膜的发展和完善.     

纳滤与反渗透膜处理含锰废水的初步研究

采用纳滤膜、反渗透膜分离技术对含锰废水进行了试验研究.考察了纳滤膜的操作压力、纯水/浓水比值、Mn2+浓缩倍数、Mn2+截留率及膜通量之间的关系.试验结果表明:纳滤膜对含锰废水有良好的处理效果,一级纳滤膜对Mn2+离子的平均截留率大于98％;浓缩倍数和膜通量随操作压力的升高而升高,2.0 MPa时,浓缩倍数可以达到8.2倍,膜通量可达到28～32 L/(m2·h).一级纳滤产生的纯水用反渗透膜进一步处理,反渗透膜对Mn2+离子的截留率在97％以上,纯水Mn2+离子浓度在0.5 mg/L以下,可以达标排放.     

超滤膜在处理农药废水过程中的膜污染行为分析

由于高级氧化后的农药废水中含有大量小分子有机物,纳滤膜被应用于农药废水处理,但是,纳滤膜对进水水质有一定的要求,需要采用混凝-超滤法对高级氧化后的农药废水进行预处理.本文考察了混凝剂种类和用量对混凝效果的影响,并对3种孔径的聚偏氟乙烯(PVDF)中空纤维超滤膜在不同压力下的抗污染性能和临界操作条件进行了研究.结果表明,当聚合氯化铝(PAC)投放量为800mg/L,三氯化铁(FeCl_3·6H_2O)投放量为500mg/L,聚丙烯酰胺(PAM)投放量为10mg/L时,混凝-超滤组合工艺对废水中化学需氧量(COD_(Cr))、总磷(TP)、浊度、色度的去除率分别达到58.0%~59.1%、88.8%~89.7%、99.8%~99.9%、84%.平均孔径为20nm的PVDF超滤膜比平均孔径为11nm和40nm的PVDF超滤膜具有更高的临界通量和渗透性能.对膜污染、通量衰减模型的考察结果显示,孔内堵塞是导致孔径减小和通量衰减的主要原因.通过优化超滤膜孔径,能够显著降低膜孔堵塞现象,获得较高的运行通量.     

厌氧膜生物反应器(AnMBR)处理高浓度豆制品废水的研究

采用膨胀污泥床反应器与外置管式超滤膜组成厌氧膜生物反应器(AnMBR)处理高浓度豆制品废水,实验连续运行240d,AnMBR平均处理量30～160L/d,研究了反应器的处理效果并获得了最佳水力停留时间(HRT).实验结果表明,AnMBR处理高浓度豆制品废水能够达到较好的效果,当进水COD为10g/L左右时,最佳HRT为18h,COD去除率约90%,此时相对应的有机负荷(OLR,以COD计)为13.6kg/(m3.d);稳定运行期间,单位COD气体产率为0.10～0.25L/g,甲烷含量在70%左右:在0.1MPa操作压力条件下进行膜的运行试验,考察了不同清洗方式的效果,采用最佳清洗方式膜通量可以恢复到新膜的90%左右.     

纳滤膜去除饮用水中苯系污染物效能试验研究

采用错流纳滤工艺开展了饮用水中苯系污染物的去除效能和纳滤运行特性的研究,考察了纳滤膜对苯、乙苯、邻二甲苯和间二甲苯的截留效果,研究了操作压力、浓水流量、离子浓度、进水温度和苯系污染物浓度等因素的影响.结果表明,随着操作压力和进水温度的升高,膜通量呈增加趋势;随浓水流量和离子浓度的升高,膜通量呈降低趋势;随着回收率、操作压力、离子浓度和进水温度的增加,纳滤膜的截留率均降低;随浓水流量和苯系污染物浓度的增加,纳滤膜的截留率升高.在所有试验条件下,纳滤膜对4种苯系污染物的截留率都介于86.56%~98.85%之间,出水中乙苯、邻二甲苯和间二甲苯含量均符合《生活饮用水卫生标准》(GB5749—2006);进水苯含量低于0.1mg/L时,出水苯含量能满足国标要求.通过研究投资和运行成本,确定出经济运行参数为回收率90%、操作压力0.6 MPa和浓水流量30L/min.     

膜蒸馏法处理催化剂废水的试验研究

利用自制的能量回收式气隙膜蒸馏组件处理催化剂废水,针对废水水质特点采用"加碱除硬+澄清+微滤+离子交换+调酸"的预处理工艺,预处理后废水中Ca2+、Mg2+浓度均小于5.0mg/L;利用正交试验方法对操作条件进行优化设计,结果表明流量Q为50L/h,进料温度T1为25℃,T3为90℃时,此时膜通量最大为4.85kg/(m2·h);流量为20L/h,进料温度T1为55℃,T3为90℃时,造水比最大为6.35;对废水经过20h的试验,废水回收率为87%,而膜通量下降缓慢,产水TDS最大为18.4mg/L,截留率大于99.9%.     

强化MBR处理含酚毒性废水及膜过滤特性的研究

考察添加白腐菌的生物强化膜生物反应器(EMBR)对含酚毒性废水的强化处理效果及其对膜过滤特性的影响.在优化工艺条件下,T=25℃,pH=6.5,水力停留时间(HRT)=10 h,菌种采用粒状活性炭(GAC)负载形式,进水TOC(总有机碳)容积负荷从0.96 kg/(m3?·d)增至2.4 k/(m3·d).实验结果表明:EMBR比传统膜生物反应器(CMBR)处理废水效果更佳(TOC平均去除超过90%),且在研究范围内负荷越高强化处理效果越显著,表明EMBR工艺具有更强的耐负荷冲击及抗毒性.此外,EMBR具有更高的临界通量[20.6 L.(m2·h)],膜持续运行时间更长,且膜污染速率及不可逆内部膜污染阻力均比CMBR有明显降低,表明其在改善膜污染方面亦具有优势.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...