陶瓷膜污染的超声波辅助清洗

膜污染的控制和膜的清洗再生是膜应用的关键,研究了采用超声波辅助清洗被乳化液污染的氧化锆陶瓷膜。结果表明：超声波的功率、超声清洗时间及膜污染程度等对清洗效果均有影响,超声功率越高,清洗后水通量的恢复率越高,超声清洗时间在20 min左右比较适宜。超声波对膜表面的污染清洗效果较好,对膜孔内堵塞清洗效果相对较弱,超声辅助化学清洗可有效恢复膜通量。     

陶瓷膜超滤薏苡仁混合油脱胶

研究了陶瓷膜在薏苡仁混合油脱胶中的应用。研究了不同截留相对分子质量陶瓷膜的脱胶效果以及过膜压力、料液温度和运行时间对膜通量的影响,并对陶瓷膜清洗工艺进行探索。选择截留相对分子质量15 000的超滤膜,在50 ℃和0.5 MPa下能够去除混合油中90%磷脂。用碱洗和次氯酸钠清洗能够彻底去除膜污染,恢复膜通量。     

陶瓷膜处理油田采出水的膜清洗方法研究

陶瓷膜凭借机械强度高、化学稳定性好、不易受到微生物侵蚀等优点，在油田采出水处理领域应用广泛。然而膜污染的问题制约了其发展，为此进行了膜清洗方法的研究。发现物理清洗对污染膜的清洗效率较低，通量恢复率低于40%。筛选了氧化剂、表面活性剂、强酸、强碱等四个类型的清洗剂，发现不同类型清洗剂中硝酸、氢氧化钠对膜的通量恢复率最高，分别为83%、49.5%。进行组合式化学清洗方案的开发，研究了药剂浓度对通量恢复率的影响，最终筛选出“2%氢氧化钠+2%硝酸”的清洗方案。在长期运行发现该方法的通量恢复率稳定在92%～100%，且陶瓷膜本身的过滤性能正常。对比污染膜和清洗后膜的SEM和EDS，发现膜表面污染层主要由有机物和无机金属元素组成，该清洗方案能对其进行有效的去除，且没有破坏膜结构。接触角的测定结果表明化学清洗提高了膜的亲水性，增加了膜的抗污能力。     

陶瓷膜再生工艺研究

对被焦化废水污染后的陶瓷膜的再生工艺进行了研究,提出了先用自来水对被污染膜进行物理清洗,在一定的时间内使陶瓷膜在没有进行化学清洗的情况下能正常工作,而且可以显著地延长化学清洗周期和膜使用寿命。对于严重污染的膜应采用化学清洗方法,根据污染物的性质,选取适宜的化学药剂进行陶瓷膜的清洗实验研究,探讨清洗药剂浓度对陶瓷膜清洗效果的影响。组合两种最佳清洗浓度的清洗剂对陶瓷膜进行连续两步清洗,清洗后膜通量恢复率可达到88%以上,有效地解决了陶瓷膜污染后的再生问题。     

陶瓷膜的清洗工艺研究

笔者对被焦化废水污染后的陶瓷膜的再生工艺进行了研究,提出了先使用自来水对被污染膜进行物理清洗,在一定的时间内使陶瓷膜在未进行化学清洗的情况下能正常工作,而且可以显著地延长化学清洗周期和膜使用寿命。对于严重污染的陶瓷膜应采用化学清洗方法,根据污染物的性质,选取适合的化学药剂进行清洗实验研究,并探讨了清洗药剂浓度对陶瓷膜清洗效果的影响。组合两种最佳清洗浓度的清洗剂对陶瓷膜进行连续两步清洗,清洗后的膜通量恢复率可达到88%以上,有效地解决了陶瓷膜污染后的再生问题。     

基于油水污染机理的动态膜清洗实验研究

制备α-Al_2O_3管状陶瓷膜基ZrO_2动态膜并将其用于油水乳化液的分离,对该过程的污染机理进行分析后,选择四种清洗剂对污染膜进行多方案清洗实验,通过理论分析确定了最佳清洗顺序,即"碱洗→吐温80→酸洗→柠檬酸"。单步清洗实验中,考察不同清洗剂浓度下的膜通量恢复率,确定各清洗剂的最佳清洗浓度与时间,清洗后渗透通量恢复情况为:氯化氢氢氧化钠柠檬酸吐温80;多步清洗试验表明,四步清洗效果最好,通量恢复率达到了79.8%;根据重复清洗试验结果,结合过滤阻力模型计算和红外测试分析,确定动态膜基膜能循环使用3~4次。研究结果对动态膜的清洗复用提供依据。     

超细TiO_2粉体洗涤过程中膜污染和再生方法研究

针对陶瓷膜洗涤超细TiO2粉体中Cl-的过程,确定了适合的跨膜压差和膜表面流速,并采用阻力系列模型分析膜污染机理,确定有效的膜再生方法。此过程渗透通量随跨膜压差和膜表面流速的增长而增长,但是增长幅度减缓。合适的跨膜压差和膜表面流速分别为0.10—0.15 MPa和2.0 m/s;主要的膜污染来自粉体在膜表面的沉积;单一的化学和物理清洗方法无法达到理想的清洗效果,采用纯水浸泡、超声波清洗和质量分数0.5%的HCl清洗可使纯水通量恢复至新膜的72%以上,且多次的清洗效果稳定。     

无机膜处理乳化废水中试研究

为除去废水中的乳化油,采用无机陶瓷微滤膜对乳化废水进行了中试实验研究.实验结果表明:乳化液废水经孔径为200 nm的无机陶瓷膜处理后,透过液可达国家排放标准;在最佳操作压力0.16 MPa下,系统可连续、稳定运行20 h以上,平均膜通量为272 L/(m2·h);化学清洗30 min后,可使膜通量恢复至初始通量的95%;平均料液运行成本为4.49元/m3.用无机陶瓷膜处理乳化液废水是一种经济、技术可行的方法.     

陶瓷膜处理废聚酯瓶片洗涤废水工艺研究

废聚酯瓶片洗涤废水属于碱性高浓度难降解废水,采用陶瓷膜错流过滤的方式进行试验,孔径50、200、500nm的陶瓷膜对SS和浊度截留率均在99%以上,渗透液存放24 h后保持澄清透明,对COD去除率为40.5%～43.3%,同时发现陶瓷膜对可溶物的透过性较好。陶瓷膜分离工艺参数优化试验表明,在膜孔径为50 nm,操作温度为40～50℃,平均错流速率为2.10 m/s,跨膜压差为0.13～0.15 MPa的条件下,陶瓷膜渗透通量衰减较慢。采用质量分数为0.2%NaClO溶液和0.3%草酸溶液的组合方式进行膜清洗试验,膜通量恢复率达80%以上。     

陶瓷膜处理乳化悬浮液过程中的膜清洗工艺

对陶瓷膜处理乳化悬浮液过程中膜清洗工艺进行了研究。考察了清洗工艺如动态清洗、温度、清洗剂浓度、操作方式等对膜层清洗效果的影响,确定了适宜的清洗工艺参数。研究结果表明:用透过液或低浓度料液在常温下对污染膜进行清洗后,可使膜通量恢复达初始通量的96%以上;停止工作后的膜后处理工艺中,清洗剂浓度对清洗效果的影响不大,但应将清洗剂在高速流动状态下来清洗油污较为适宜。     

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.     

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…     

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。     

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.     

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.     

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。     

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。     

典型煤碳燃烧特性研究和数值模拟

本文以三种典型煤的碳燃烧为研究对象，分别采用简单一维沉降燃烧方式和等温加热燃烧方式，实验研究了煤在快速加热条件下，其碳的初期和中，后期燃烧过程。以实验为基础，建立了煤的碳燃烧模型，变工况数值模拟了煤的碳燃烧过程，揭示了煤不同条件下的单颗粒碳燃烧特性。