连续微滤用于海水净化的运行条件优化

采用连续微滤技术进行反渗透海水淡化预处理中试,通过正交实验考察连续微滤前处理工艺、过滤模式及膜通量、运行时间、反洗通量、反洗时间等运行条件对产水水质、单位净产水量跨膜压差增长量及产水率的影响,并对运行条件进行优化。结果表明,前处理工艺、膜通量和运行时间是影响单位净产水量跨膜压差增长量的显著因素,而过滤模式是影响产水率的主要因素。"混凝-沉淀-砂滤"作为前处理工艺可有效减少连续微滤进水的悬浮物含量;对外压式中空纤维膜而言,错流过滤减轻膜污染的效果不明显,宜采用死端过滤模式;其他优化运行参数为:通量40L/(m~2·h),运行时间30 min,反洗通量60 L/(m~2·h),反洗时间60 s。     

浸没式超滤膜过滤工艺处理珠江微污染水的研究

利用浸没式超滤膜过滤工艺处理微污染珠江水,运行参数为膜通量556L／m2·h、运行周期2h,采取气水反冲洗方式,在反洗时间为5min、反洗水量1．5m‰、反洗气量2m^3／h时,对浊度的去除率在99．5％以上,出水浊度在0．06～0．12NTU之间;对藻类的去除基本达到100％;对CODM。的去除率在47％左右,出水CODM。在2．6～45mg／L之间,去除效果一般;对氨氮的去除率只有10％左右,基本没有去除效果。     

无机炭膜在处理含油污水中的应用研究

采用无机炭膜处理油田采出水,解决油田采出水处理后达标回注的问题,研究了水的回收率、温度、膜的反洗方式和频率对跨膜压差的影响。结果表明,含油量25～30 mg/L,悬浮物含量15～35 mg/L的含油污水,在装置的膜面积1.6 m²、进水流量4.5 m2、进水流量4.5 m³/h、水温20～25℃、水的回收率75%的条件下,经过0.04μm孔径无机炭膜处理后,含油量≤3.0mg/L,悬浮物≤1.0 mg/L,水质能够满足低渗透油田回注水水质标准;反冲洗及脉冲反洗有助于膜通量的恢复,反洗周期30 min。     

超滤膜在市政污水回用中的应用中试

以某污水处理厂二级出水作为源水,建立日处理水量110 m3/d的超滤膜(UF)中试装置,研究超滤膜在市政污水回用中以恒定流量方式运行时,跨膜压差(TMP)增加的趋势、化学加强反洗(CEB)的效果和出水水质的情况。结果表明,当超滤膜产水量在4.62 m3/h,通量保持60 L/(m2·h)时,随着运行时间的增加,超滤膜TMP逐渐平稳地增加,通过CEB后能够将运行压力恢复至65 k Pa左右,产水浊度能够控制在0.1 NTU以下,膜系统运行稳定。     

超滤膜处理油田采出水试验研究

为提高回注水水质,对PVDF超滤膜在油田采出水处理过程中操作参数的选择及膜污染机理进行了研究,通过现场试验,分析了不同的操作参数对膜通量的影响,超滤膜对含油量及悬浮物的去除效果,膜污染清洗方法。结果表明,超滤膜过滤的优化操作条件为:在确定出水水质达到SY/T 5329-94低渗透油田注水水质A1级标准条件下,温度50℃,浓水回流体积比50%,在线反冲洗周期25 min;NaOH和HNO3联合清洗有助于恢复超滤膜膜通量。     

无机炭膜在处理含油污水中的应用研究

采用无机炭膜处理油田采出水,解决油田采出水处理后达标回注的问题,研究了水的回收率、温度、膜的反洗方式和频率对跨膜压差的影响。结果表明,含油量25～30 mg/L,悬浮物含量15～35 mg/L的含油污水,在装置的膜面积1.6 m~2、进水流量4.5 m~3/h、水温20～25℃、水的回收率75%的条件下,经过0.04μm孔径无机炭膜处理后,含油量≤3.0mg/L,悬浮物≤1.0 mg/L,水质能够满足低渗透油田回注水水质标准;反冲洗及脉冲反洗有助于膜通量的恢复,反洗周期30 min。     

一体式自生动态膜生物反应器的运行特性

采用涤纶短纤滤布作为分离介质构成一体式动态膜生物反应器(DMBR)处理模拟生活污水,对反应器处理效果、运行特性进行研究。结果表明,在一个运行周期内,分析DMBR的过滤压差和膜通量变化,在运行10h以后,反应器出水水质趋于稳定,动态膜基本形成,膜通量基本维持在37.9L/(m2.h)。DMBR对COD、氨氮、总氮的平均去除率分别为89.00%、82.50%、44.85%,出水浊度维持在1NTU左右,反应器的反冲洗周期为30h左右,出水水质优于城镇污水处理厂污染物排放一级A标准(GB18918—2002),可回用于城镇景观用水等。     

PVDF/PVP改进超滤膜用于城市污水再生时的膜清洗方式与调控试验研究

对城市污水二级处理水经混凝沉淀、砂滤预处理后,利用自主制备改进的PVDF/PVP超滤膜和开发的全自动膜分离装置进行再生处理,考察了不同水力清洗操作条件和加药反洗对抑制膜污染的效果及相关参数,并与国内外应用广泛的超滤膜作了比较。结果表明,(1)改变水力清洗条件时,反洗流量的改变可以在很大程度上减缓PVDF/PVP改性膜的膜污染,当反洗流量由产水流量的1.5倍逐渐扩大到2倍时,以跨膜压差增长率所表示的膜污染速率由0.387(kPa.m2)/d减少到0.085(kPa.m2)/d,膜污染速率减少78%;(2)最佳水力清洗方式下跨膜压差增长程度控制在1.11～1.37 kPa左右时,采用次氯酸钠溶液加药反洗可以使跨膜压差完全恢复,最佳水力清洗方式为反洗时间80 s、流量640 L/h,快洗时间60 s、流量800 L/h,加药反洗周期为120个过滤周期;(3)PVDF/PVP改进膜水力清洗与加药反洗时,清洗压力与耗水量较低于国内外一些主要超滤膜产品的运行参数,表明具有抗污染强、恢复效果好和能耗低的优点     

盘式过滤器工艺性能对比试验研究

设计了并联式的过滤系统,将国产、进口的盘式过滤器进行了工艺性能对比试验。针对不同过滤精度的盘片在不同的加药量下,对比研究了两种过滤器进出水的浊度和悬浮固体含量、周期产水量、FPI值、水头损失、流量、反洗等工艺性能参数的差异。试验结果表明:在相同试验条件下,两种过滤器的工艺性能和出水水质参数都相近。     

反冲洗参数对砂滤池效能及微生物的影响

根据水厂运行经验,砂滤池运行一段时间后,出水水头上升,出水浊度、色度、三氮等水质指标均有不同程度增加,文章全面探究分析多因子多条件的正交试验结果,优化滤池反冲洗组合方式和具体参数,采用的反冲洗周期约为48 h,以常规指标浊度和生物指标生物量减小率和生物活性降低率为参比,确定砂滤池气水反冲洗的具体方式和参数,气冲强度为15 L/m2·s,气冲时间为2 min,气水混冲强度分别为15L/m2·s和4 L/m2·s,气水混冲时间为5 min,单独水冲强度为8 L/m2·s,水冲时间为4 min,总时间为11 min。为水厂日常生产提供技术参考。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。