超滤技术在微污染水源水处理中的研究与应用

介绍粉末活性炭/超滤、混凝/超滤、浸没式超滤膜等组合工艺的特点及对微污染水源水的处理效果,分析投加粉末活性炭、混凝剂对膜通量膜污染的影响,指出超滤组合工艺的发展前景和今后的研究重点、方向。     

污泥膨胀对膜生物反应器脱氮效果的影响

通过采用A/O膜生物反应器工艺处理生活污水的动态模拟方法,研究污泥膨胀对该系统脱氮效果的影响。结果表明:污泥膨胀对总氮的去除率基本无影响,丝状菌比表面积大,在低底物浓度的条件下对基质的亲和能力比菌胶团强,使得CODCr的平均去除率提高了3.8%,NH3-N的平均去除率提高了3%。丝状菌的捆绑、覆盖所引起的膜污染极其严重,膜通量无法保持稳定。     

污泥膨胀对膜生物反应器脱氮效果的影响

通过采用A/O膜生物反应器工艺处理生活污水的动态模拟方法,研究污泥膨胀对该系统脱氮效果的影响。结果表明,污泥膨胀对总氮的去除率基本无影响,丝状菌比表面积大,在低底物浓度的条件下对基质的亲和能力比菌胶团强,使得CODcr的平均去除率提高3.8%,NH3-N的平均去除率提高3%。丝状菌的捆绑、覆盖所引起的膜污染极其严重,膜通量无法保持稳定。     

厌氧膜生物反应器处理有机垃圾渗滤液的COD去除率与膜过滤性能研究

考察厌氧膜生物反应器（AnMBR）在依次改变膜过滤通量[7 L/(m²∙h)、6 L/(m²∙h)、5 L/(m²∙h)、4 L/(m²∙h)]运行下处理实际有机垃圾渗滤液的膜过滤性能,分析了膜污染后污染物阻力分布状况。在水力停留时间（HRT）为10 d、固体停留时间（SRT）为100 d、有机负荷（OLR）为5 ~ 6 g-COD/(L∙d) 的条件下运行104 d。实验结果显示,化学需氧量（COD）的去除率可以达到90% ~ 93%,过滤通量增加后压缩泥饼层使COD去除率有所提高。在初始通量为6 L/(m²∙h) 下实现了较好的过滤性能,增加通量至7 L/(m²∙h) 后不可逆污染会快速形成,即使通量再降低至5 L/(m²∙h),甚至4 L/(m²∙h) 后,膜过滤性能仍较差。通过膜清洗测定过滤阻力分布,结果显示泥饼层阻力占总阻力的52%,是造成膜污染的主要因素。降低运行通量对不可逆污染恢复效果差,需及时进行化学清洗,可通过分析膜污染特征调整清洗策略,优化试剂使用量。     

硅藻土错流动态膜工艺对淮河原水除浊效果的影响

以淮河原水为例,研究了3种硅藻土预涂动态膜错流过滤工艺的运行特性及其对原水除浊效果的影响。结果表明,单纯采用硅藻土作为预涂动态膜（硅藻土预涂动态膜错流过滤工艺）进行过滤难以有效降低出水浊度,出水浊度较高（2.86~12.08 NTU）;投加一定浓度聚合氯化铝进行混凝（硅藻土预涂—聚铝混凝动态膜错流过滤工艺）可使出水浊度降低,但出水时间仍较短;采用硅藻土和粉末活性炭作为预涂剂并投加低浓度聚合氯化铝进行混凝（硅藻土/粉末活性炭预涂—聚铝混凝动态膜错流过滤工艺）可显著改善动态膜纵向层级结构,平均出水浊度低于0.25 NTU,且有效出水时间得以延长,其过滤过程更符合标准过滤模型。     

硅藻土错流动态膜工艺对淮河原水除浊效果的影响

以淮河原水为例,研究了3种硅藻土预涂动态膜错流过滤工艺的运行特性及其对原水除浊效果的影响。结果表明,单纯采用硅藻土作为预涂动态膜(硅藻土预涂动态膜错流过滤工艺)进行过滤难以有效降低出水浊度,出水浊度较高(2.86~12.08NTU);投加一定浓度聚合氯化铝进行混凝(硅藻土预涂—聚铝混凝动态膜错流过滤工艺)可使出水浊度降低,但出水时间仍较短;采用硅藻土和粉末活性炭作为预涂剂并投加低浓度聚合氯化铝进行混凝(硅藻土/粉末活性炭预涂—聚铝混凝动态膜错流过滤工艺)可显著改善动态膜纵向层级结构,平均出水浊度低于0.25NTU,且有效出水时间得以延长,其过滤过程更符合标准过滤模型。     

一体式MBR中好氧颗粒污泥的形成及对膜污染的影响

以厌氧颗粒污泥为接种污泥在一体式膜生物反应器中培养好氧颗粒污泥,通过3个培养阶段污泥生长情况的考察,研究了颗粒粒径和SOUR的变化以及二者对膜污染的影响.     

复合式/一体式膜生物反应器处理生活污水中试试验对比研究

用中试对比进行一体式与复合式膜生物反应器对于生活污水污染物的去除研究。发现2种膜生物反应器对于COD的总去除率都在96%左右;对于氨氮的去除率都在90%以上,2者在处理效能上并无太大区别;但复合式膜生物反应器对于总氮的去除高了10%,同时污泥浓度大大降低,使膜污染降低,污泥脱水性能增加。     

活性焦联合陶瓷平板膜处理油田采出水的试验研究

考虑到油田采出水中含有较多的难降解有机物,采用生物法对油田采出水进行处理效果不理想,所以本试验采用活性焦+陶瓷平板膜对采出水中的有机物进行吸附截留处理。试验主要探讨了活性焦投加量、水力停留时间、曝气等因素对处理效果的影响。结果表明反应器最佳工况参数为:活性焦投加量1.8 kg/t,吸附时间60 min。在最佳参数运行条件下,反应器出水COD浓度小于50 mg/L,达到一级A出水标准。同时,曝气可以有效降低膜污染程度,延长陶瓷平板膜的寿命。     

无机陶瓷平板膜处理生活污水试验研究

试验采用无机陶瓷平板膜生物反应器处理生活污水。试验结果表明:该试验系统COD的去除率达75%以上,NH_4~+-N的去除率稳定在85%左右,TP的平均去除率为33.54%,去除效果较理想;采用物质浓度为0.1mol/L的HCl溶液浸泡被污染的膜片12h,可对污染膜片实现有效清洗。     

金属膜生物反应器运行参数的优化研究

采用正交试验法对浸没式平板金属膜生物反应器(MBR)进行运行参数的优化研究。试验选择抽停时间比、曝气量、反洗频率与反洗水量等4个参数为因素,使用膜操作压力变化率K进行评价,结果表明各参数对膜过滤性能的影响为:抽停时间比>反洗频率>反洗水量>曝气量;优化运行参数为:抽停时间比6∶1,反洗频率2次/h,反洗水量2m3/(m2.d),曝气量10L/min。膜过滤阻力组成部分的测定表明,滤饼层阻力为膜阻力的主要组成部分,曝气量过大会导致膜内部污染的加剧。     

实现以煤代油的有效途径

提出了采用改进后的发生炉煤气 (工业用 )来实现以煤代油 ,是解决我国煤多油少矛盾的有效途径。这种炉为常压 (0 .0 6MPa) ,其强度高达 110 0kg (m2 ·h) (常规发生炉煤气的强度最高达380kg m2 ·h) ,煤种适应性广 ,煤气热值低 ,但比常规的发生炉煤气的热值要高 (约提高 10 % ) ,供工业用完全合适     

Performance of solid particles flow thermal storage material made of desert sand

It is a safe and low-cost new heat storage method to realize sensible heat storage at medium and high temperature by using flowing inorganic inert solid particle materials. The cost and performance of granular heat storage medium are very important for this kind of heat storage technology. The yellow sand in southeast of Tenggri Desert in Ningxia is studied. By thermal shock and grinding methods, the tests of thermal shock-resistance and wear resistance were carried out, under laboratory conditions, for the unscreened raw sand and the screened sand samples with three grain sizes (40–60 mesh, 60–80 mesh, and 80–100 mesh). The particle size of the raw sand is 150–300 µm (60–100 meshes) accounts for 60% (wt %) or more and meets the requirement of heat storage material. The density, thermal conductivity, and specific heat of raw sand are higher than those of three kinds of screened sand. Thermal shock and grinding affect the particle size distribution, density, specific heat, and thermal conductivity of the particles. The degree of influence varies with the particle size. The volume ratio heat capacity is used to measure the heat storage performance of the particles. Thermal shock results in a better thermal storage performance of the screened sand than the original sand. After comprehensive analysis of the properties of three kinds of screened sand, it is found that the content of 60–80 mesh-screened sand (31.75%) is the highest in the original sand. After thermal shock and grinding, the screened sand not only has good heat storage performance (average volumetric specific heat capacity 3.232 J· K^?3· K^?1), but also has the smallest change of particle size (breaking rate is less than 24, and agglomeration rate is less than 6), and the thermal shock resistance and wear resistance are outstanding. It is suggested that the screened sand with the particle size range of 200-300µm (60–80 mesh), also the particles with the highest content in the original sand, should be selected as the solid particle flowing heat storage medium.     

Numerical simulation for the effect of vaporization intensity in membrane on the performance of PEM fuel cell

The heat and mass transfer characters of proton-exchange membrane (PEM) fuel cell have major impact on the performance of cell system, and suitable moisture content in the membrane is one of the most important enhancing factors of PEM fuel cell systems. In this article, the effect to different vaporization mechanism of water in the membrane is investigated numerically, the results show that the temperature of the fuel cell increases with lessens of the heat transfer coefficient, and the average temperature located in membrane is reduced most significantly by 18.03% compared to no vaporization condition in membrane for cases in which heat transfer coefficient is 50?W/m²?·?K. Furthermore, the current density with evaporation in membrane is much lower than take no account of vaporization, especially on the cathode side; meanwhile, the excess percentage of oxygen and water vapor concentration is more significantly different from the condition without vaporization when the fuel cell temperature reaches the boiling point.     

Numerical study of PEMFC heat and mass transfer characteristics based on roughness interface thermal resistance model

The thermal contact resistance (TCR) is the main component of proton exchange membrane fuel cell (PEMFC) thermal resistance due to the existence of surface roughness between the components of PEMFC, and the influence of TCR is often ignored in traditional three dimensional PEMFC simulations. In this paper, the heat and mass transfer characteristics including polarization curve, power density curve, temperature distribution, membrane water content distribution, membrane current density are studied under different component surface roughness conditions, and finally the effect of each TCR on the PEMFC performance is studied. It is found that under the same operating conditions, the TCR makes the radial heat transfer of the PEMFC decrease, and the temperature of the membrane electrode and the temperature difference of each component of the PEMFC is higher than that of the model without TCR. When the surface roughness of components in the PEMFC equals 1 μm, 2 μm, 3 μm, the cell current density decreases by 6.56%, 12.46% and 17.17% respectively when the output cell voltage equals 0.3 V, and the cell power density decreases by 3.64%, 7.54%, 13.14% respectively when the cell current density equals 1.2 A·cm^?2. When the TCR between the CL and PEM equals 0.003 K·m²·W^?1, 0.005 K·m²·W^?1, 0.01 K·m²·W^?1, the cell current density is increased by 2.30%, 3.65%, 6.74% respectively under the condition that the output cell voltage equals 0.3 V, and the cell power density is increased by 1.24%, 1.85%, 3.10% respectively when the cell current density equals 1.2 A·cm^?2. The results show that the numerical simulation of PEMFC cannot ignore the effect of TCR.     

污水处理场MBR膜通量下降原因及缓解措施

中国石化海南炼油化工有限公司的污水处理场采用了MBR工艺处理其炼油污水,设计处理能力为450m3/h.进入2008年以后,MBR膜在运行中出现膜通量下降较快的问题,造成实际生产能力不到设计值的1/2.通过分析,造成膜通量下降的原因为:系统中污泥龄较长,污泥颗粒细小,沉降性能差,容易形成生物黏泥；进水油含量超标以及吹扫风带油,造成油类污染；反洗频次较高,而且反洗水质得不到保证;系统膜组件的抖动风设计不合理,风量供应不均,风孔有堵塞现象；现场操作不当,导致膜丝间积存大量活性污泥,缠裹膜丝.采取了有针对性的措施:缩短污泥龄,降低活性污泥对膜的粘附性;调整清洗方案及药剂,采用1％氢氧化钠和0.3％次氯酸钠对膜件进行离线化学清洗；提高膜区风量,改进膜件底部的布气设施;优化工艺操作,控制进水油含量和吹扫风带油；加强溶气浮选的运行控制以及现场操作.措施实施后,MBR系统处理量由2006～2009年的180～220m3/h提高到2012年的140～160m3/h,跨膜压差控制在35～55kPa,膜通量的下降幅度远远低于前措施实施前,出水水质保持稳定.     

Improving the proton conductivity of sulfonated poly (ether ether ketone) membranes by incorporating a crystalline nanoassembly of trimesic acid and melamine

A novel proton exchange membrane was synthesized by embedding a crystalline which was nano-assembled through trimesic acid and melamine (TMA·M) into the matrix of the sulfonated poly (ether ether ketone) (SPEEK) to enhance the proton conductivity of the SPEEK membrane. Fourier transform infrared indicated that hydrogen bonds existed between SPEEK and TMA·M. XRD and SEM indicated that TMA·M was uniformly distributed within the matrix of SPEEK, and no phase separation occurred. Thermogravimetric analysis showed that this membrane could be applied as high temperature proton exchange membrane until 250 °C. The dimensional stability and mechanical properties of the composite membranes showed that the performance of the composite membranes is superior to that of the pristine SPEEK. Since TMA·M had a highly ordered nanostructure, and contained lots of hydrogen bonds and water molecules, the proton conductivity of the SPEEK/TMA·M-20% reached 0.00513 S cm⁻¹ at 25 °C and relative humidity 100%, which was 3 times more than the pristine SPEEK membrane, and achieved 0.00994 S cm⁻¹ at 120 °C.     

运行方式对膜生物反应器处理生活污水影响的试验研究

采用模拟的生活污水,调节适当的pH值,MLSS控制在4~5g/L之间,在常温条件下,试验研究连续曝气和间歇曝气两种运行方式对有机物和氨氮的去除效果以及对膜污染的影响。从处理效果和处理能力上综合考虑间歇曝气的可行性。试验结果表明:合理的间歇时间能提高膜生物反应器对有机物和氨氮的去除效果。在不同运行条件下,膜过滤阻力在系统运行初期没有明显的差异,只是在运行后期,间歇曝气的膜过滤阻力才出现明显的上升。     

Offshore wind climatology over the Mediterranean basin

To obtain the offshore wind climatology over the whole Mediterranean region, European Centre for Medium‐range Weather Forecasts (ECMWF) 6‐hourly wind data over a grid resolution of 0·5° × 0·5° for a period of 24 years have been retrieved. Data sets at 850 and 700 hPa pressure levels and 10 m above the surface were downloaded. For each grid point, mean wind speeds and Weibull probability density function parameters have been computed. As the wind field of ECMWF at 10 m is less accurate near the coast and in narrow basins, e.g. the Adriatic Sea, owing to the size of the mesh and land–sea mask smoothness, these statistics have been corrected, for each grid point, with the statistics produced using 2 year runs of a limited‐area model with a grid size of 10 km. Results have been compared with experimental data from buoys, islands and ships in various regions of the basin. Maps of mean wind speeds and Weibull parameters are shown here for the whole Mediterranean Sea to illustrate these results. Copyright © 2005 John Wiley & Sons, Ltd.     

Estimation of bed expansions in a freely-bubbling three-dimensional gas-fluidized bed

Knowledge of bed expansions is important in the design and operation of gas–solid fluidized beds. This paper presents a study on the estimation of expanded bed height in a large three-dimensional gas-fluidized bed with a square section of 0·61×0·61 m². All experiments were performed at the freely bubbling mode and the bed expansions were recorded by a video camera. Bed materials were used 593 μm raw perlite and 1233 μm sand falling within the categories of Geldart's Groups B and D, respectively. The bed height at minimum fluidization ranged from 0·0398 to 0·3176 m, while the excess air velocity from 0·034 m s⁻¹to 0·7453 m s⁻¹. Equations related to the bed expansion were given using a modified form of two-phase theory of fluidization. A correlation for the average bed expansion (void fraction) was also presented that has been derived from the principal form found successful in gas–liquid systems as follows: R=0·5482 d^−0·129_p(U_o−U_mf)^0·111 with an average deviation of less than 1%. The experimental findings were compared with previously reported results and were discussed in the light of available correlations. © 1998 John Wiley & Sons, Ltd.