深层滤床反冲洗技术及其油田水处理领域应用进展

深层滤床过滤作为油田污水高效处理最重要的环节之一,滤床稳定运行的关键在于有效反冲洗。随着含油废水中聚合物浓度不断增大,聚合物吸附和滞留于滤床内,与滤料颗粒相互黏结,滤床反冲洗不彻底,导致滤床板结、过滤效率降低甚至作用失效。为了解决这一问题,本文介绍了重力作用下滤料反冲洗再生原理,回顾了单独水反冲洗技术、气水联合反冲洗技术及其加载场强化水力反冲洗技术,提出了一种颗粒滤床复合场反冲洗的新方法,将旋流场加载于滤床重力场的水力反冲洗过程,可以突破重力作用下滤料反冲洗再生效率低的技术瓶颈,丰富和发展了滤床水力反冲洗理论,为油田颗粒滤床反冲洗再生开辟新途径。     

颗粒滤料反冲洗技术现状与应用进展

过滤是水处理的常用手段之一,反冲洗是保证滤料过滤性能的重要手段。重点介绍了颗粒滤料反冲洗技术的工作原理及特点,反冲洗方式、工艺优化及工艺理论研究进展及应用现状,并分析了颗粒滤料反冲洗技术的发展趋势。     

活性碳-石英砂双层滤池去除氨氮和亚硝酸盐氮的特性

通过一个水文年的小试试验,研究了活性炭-石英砂双层滤池(简称炭砂滤池)作为快滤池时对水中氨氮和亚硝酸盐氮的去除特性。结果表明:炭砂滤池能稳定且有效去除水中的氨氮和亚硝酸盐氮,试验期间滤池出水氨氮浓度一般低于0.1 mg/L,出水NO2--N浓度一般低于检出限,运行效果优于水厂传统砂滤池。在试验进水水质条件下,氨氮和亚硝酸盐氮主要在滤池上部0.4 m活性炭层被去除。高滤速和水力波动会使炭砂滤池去除氨氮和亚硝酸盐氮的效果变差。水温和反冲洗对滤池去除氨氮和亚硝酸盐氮的效果影响不大,高温条件以及反冲洗后滤池对氨氮和亚硝酸盐氮的沿程去除速率略有提高。     

采用超临界技术制备高性能生物滤料的实验研究

采用超临界CO2萃取技术制备高性能的核桃壳滤料,考察了萃取温度、压力及时间对萃取效果的影响。实验结果表明,在萃取温度为45℃,萃取压力为35 MPa,萃取时间为2 h条件下,制备出的核桃壳滤料明显优于常规滤料,平均孔径2.62×10-7cm,比表面积高达9.30 m2/g,总孔容积6.1×10-3cm3/g,约为常规滤料的4倍。大大延长了滤料的运行周期和使用寿命,减少滤料的反冲洗次数,具有很好的节水和处理水的性能。实现了核桃壳的再生利用,达到了以废治废的目的,具有较高的经济效益和社会效益。     

Toward an Optimization of the Backwashing Process in the Flexible Fiber Filter

Abstract

Backwashing process was used to recover the retention capacity of a deep bed filter. A field scale fiber filter was operated with an in‐line injection of a coagulant for the treatment of natural surface water (Nak‐dong River in Korea). A mass balance of SS could be made thus allowing a direct estimation of the effectiveness of the backwashing process. The purpose of this paper was to study the influence of two parameters of backwashing (air injection and number of backwashing stages) on its effectiveness. The backwashing efficiency was estimated through the initial pressure drop after the backwash, the effluent quality, the duration of the filtration time between two successive backwashes, and the detached mass of retained suspended solids. Conditions could be found for removing 99% of the retained SS. As a general conclusion, the effectiveness of backwashing mainly depended upon air injection. The duration of air injection and the number of sequences were the most important factors related to the efficiency of backwashing.     

玻纤滤材过滤阻力的预测

过滤阻力和过滤效率是玻纤空气滤材的关键参数。实际应用中,为了优化滤材阻力和效率之间的矛盾,通常会选择多种尺寸的纤维搭配使用。对这种滤材的过滤阻力进行预测,对于高性能滤材的研制具有重要意义,而目前对玻纤滤材过滤阻力的理论计算大部分还局限于单种纤维的理想情况。本文将针对由多种玻纤原料制备的滤材,根据不同玻纤的比表面积,利用Kozeny-Carman方程计算由此制备的滤材过滤阻力。这种方法计算的过滤阻力理论值与实际测量值非常接近,相关系数R2=0.996 9,可为过滤材料的优化设计提供一定的依据。     

运行条件对给水超滤膜装置工作周期的影响

杂质的截留和有机物的吸附使超滤膜通量降低,频繁的化学清洗或更换膜组件使制水成本上升.试验比较了几种运行方式对超滤膜装置过滤性能的影响,探讨其对延长超滤膜装置运行的效果,研究结果表明:超滤膜装置的反冲洗不能等到膜组件污染物聚集稳定后再进行;在一定的过滤时间间隔后设定短暂的反冲洗,其效果优于膜组件污染稳定后的反冲洗;当膜清...     

Enhancement of media filter performance with coagulant use for treatment of diesel oil contaminated surface water

The objective of this study was to investigate the effect of coagulant addition on the filter performance and effluent quality during media filtration of surface water contaminated with diesel oil. A pilot scale multi-media filter system was operated under constant head conditions and at a constant loading rate of 30 L/min. The tests were conducted with and without coagulant addition prior to filtration of the surface water contaminated with diesel oil. Each filtration run was continued until the pressure drop increased to 0.7 bar. The source water with a turbidity of 10-15 NTU was prepared by mixing bentonite clay with tap water. The effect of coagulant addition on the performance of a multi-media filter for treatment of diesel oil contaminated source water was evaluated based on pressure change, filter run time before the filter clogged, and turbidity removal. The coagulant addition significantly improved the operational time of the media filter by reducing the rate of clogging. Both turbidity and PHC removal was achieved during the runs with coagulant addition.     

Experimental and analytical modeling of the filtration mechanisms of a paper stack candle filter

A candle filter consisting of a paper stack is an adequate device to clarify the grinding oil employed in the industrial post-processing of hard metal because of its cleaning efficiency and its regenerative capability by means of backwashing. The complex particle deposition mechanisms occurring in this device have not yet been investigated. Filtration experiments with a suitable particle-oil suspension were performed in a pilot filter and in a laboratory filter in order to investigate and model the mechanisms taking place in the process. The effect of operating parameters such as particle concentration and pressure difference on filter performance was evaluated. The results show that more than one filtration mechanism takes place simultaneously. While some depth filtration occurs at the beginning of the lifetime of a candle filter, blocking and cake filtration are the major mechanisms responsible for the filter clogging. Although blocking and cake filtration occur, to some extent, simultaneously, the cake filtration is the mechanism relevant for the modeling and scale-up of the long term filtration process.     

水清洗对空气净化材料过滤性能的影响

用于空气净化的材料一般为一次性使用,但有的应用场所需要对其进行反复水清洗多次使用。通过实验手段,研究常规涤纶纤维层滤料,在荷尘、清洗、烘干、荷尘等多次反复中其过滤效率、阻力、容尘量的变化情况。实验结果表明,清洗对滤料的过滤效率、阻力和容尘量没有明显的影响,滤料可以通过水清洗的方式反复使用。     

高通量陶瓷膜研制及其除藻性能的初步研究

针对富营养化水中藻细胞的去除,研制了通量大、强度符合使用要求的无机陶瓷膜。所研制的陶瓷膜具有通量大、过滤精度高、易反冲再生等优点。过滤压差为0.08MPa时,清水通量为15.79m^3/（m^2·h）,对水中微型颗粒物的分离精度为0.06μm,且可反冲再生。对富营养化湖水深度处理实验表明,该陶瓷膜可有效去除“混凝-沉淀-砂滤”工艺出水中残存的藻细胞;对水中CODMn、TP也有一定的去除效果。研究结果为富营养化源水中藻细胞的去除提供了新的技术途径。     

降低腈纶溶剂NaSCN系统含杂的研究

针对超滤技术在腈纶溶剂二步法硫氰酸钠系统应用中存在的问题开展试验研究,主要考察了不同类型超滤膜(内、外压膜差异以及膜丝固定形式差异)的投用效果、产料反冲洗及进料方式对膜运行周期的影响等。通过试验可知:投用超滤膜对二步法料液中水不溶物有一定的去除效果;采用新型超滤膜(膜丝一端固定),其过滤周期是传统两端固定超滤膜的2.5倍;内压式超滤膜不适用于处理二步法硫氰酸钠料液;增加产料反冲洗能显著提高过滤时间、过滤总流量。经过优化,基本解决了存在的膜通量无法恢复、过滤时间短、通量衰减过快等问题,为产业化改造提供依据。     

连续砂滤—超滤组合工艺的除污染效能与优化

构建了连续砂滤-超滤中试组合工艺,研究了其的除污染效能。结果表明,增加滤层厚度、降低滤速及延长洗砂周期均有助于提高连续砂滤的除污染效果。加氯反冲洗对超滤的除浊效果无影响,可以更有效地洗脱类腐殖质、类蛋白质以及微生物代谢产物等污染物,洗脱率比水力反冲洗的分别提高了57.9%、99.7%和107.3%,有效缓解了超滤的不可逆膜污染,超滤系统可以长期稳定运行,不需进行化学清洗。组合工艺的浊度去除效果极佳,出水浊度始终低于0.1 NTU;CODMn和UV254的去除率分别达34.2%和21.8%。连续砂滤有效控制了微污染原水的浊度和有机物含量,确保超滤系统可以稳定运行。研究成果可为微污染水源水的物化处理工艺提供技术支持。     

混凝耦合多孔陶瓷膜净化河水简

Membrane filtration technology combined with coagulation is widely used to purify river water. In this study, micro filtration （MF） and ultrafiltration （UF） ceramic membranes were combined with coagulation to treat local river water located at Xinghua, Jiangsu province, China. The operation parameters, fouling mechanism and pilot-scale tests were investigated. The results show that the pore size of membrane has small effect on the pseudo-steady flux for dead-end filtration, and the increase of flux in MF process is more than that in UF process for cross-flow filtration with the same increase of cross-flow velocity. The membrane pore size has little influence on the water quality. The analysis on membrane fouling mechanism shows that the cake filtrationhas significant in fluence on the pseudo-steady flux and water quality for the membrane with pore size of 50, 200 and 500 nm. For the membrane with pore size of 200 nm and backwashing employed in our pilot study, a constant flux of 150 L-m^-2-h^-1 was reached during stable operation, with the removal efficiency of turbidity, total organic carbon （TOC） and UV254 higher than 99%, 45% and 48%, respectively. The study demonstrates that coagulation-porous ceramic membrane hybrid process is a reliable method for river water purification.     

水淬渣处理电厂生活污水的试验研究

通过石英砂和水淬渣单层滤料的对比试验,了解水淬渣的过滤性能.并采用水淬渣-石英砂双层滤料不加药直接过滤技术对电厂生活污水二级出水进行深度处理.试验结果表明:在去除浊度方面,水淬渣和石英砂的过滤性能相差不大;在去除COD方面,水淬渣的过滤性能优于石英砂.滤速为7.5 m/h时,水淬渣-石英砂滤料的平均出水浊度＜3 NTU、COD＜15 mg/L,满足回用标准,出水水质稳定.     

Filter life comparison of different levels of nanofiber coated cleanable-surface filter for gas turbine

High-efficiency air filtration is a basic requirement for the most cost-effective operation of high-efficiency gas turbines. The filtration system protects the gas turbine from damaging debris. In gas turbine/dust collector applications, higher efficiency filtration could be achieved with nanofibers, which provide higher equipment protection than traditional media. With a nanofiber performance filter layer, the dust accumulates on the surface of the filtration media rather than within the media and could be cleaned off easily with a back pulse resulting in long filter life and a low-operating pressure drop. In this study five type of gas tribune nanofiber coated corrugated cellulose/synthetic filter media were developed. Nanofiber coating was adjusted for five filtration efficiency level, 50 ≤ E < 60, 60 ≤ E < 70, 70 ≤ E < 85, 85 ≤ E < 95 and 95 ≤ E, pore size and filter-life of the developed media were evaluated. One of the developed nanofiber coated media was also compared with two other commercial nanofiber coated gas tribune filter media, a glass fiber type filter media and a commercial fine fiber gas tribune filter media. It was seen that, with decreasing penetration levels due to nanofiber coating level, initial 30 cycle durations of filter life evaluation could reach about 229.9 to 250.7 min. Highest final cycle duration of 188.7 min belonged to cellulose/synthetic blend corrugated filter media with penetration of 13.66%. Nanofiber based surface filter media was cleaned up better than fine fiber media and final 30 cycle sequences were significantly higher. Surface of the nanofiber coated media was smoother when compared to fine fiber media and during the initial and final cycle test dust could not penetrate inside and could not hang to this smooth surface. So, with back pulse cleaning cake releasing have performed easily. It was also seen that, for higher filter life nanofiber coating should be uniform and robust to back pulse cleaning.     

微米级高分子精密过滤技术及其在精细化工、水处理与环保领域的应用

微米级高分子精密过滤既能澄清过滤 ,也能滤饼过滤 ,还能卸干滤饼 ,过滤介质能高效再生 ,耐化学性能好 ,是一种使用寿命长的新型过滤技术。主要介绍了该技术的组成特点及其在精细化工、水处理及环保领域的主要应用。     

砂滤技术在水处理研究中的进展

对砂滤技术进行了简要的概述。从级配、滤料种类、特殊水质等方面对影响过滤的几个重要因素进行了论述。从除浊、除氨氮、除铁锰、除藻等方面详细的论述了砂滤技术的应用现状。对砂滤工艺中存在的问题,从滤料改性、微絮凝过滤、生物强化过滤等方面总结了强化过滤的措施和发展趋势。     

Evaluation of coagulation and PAC adsorption pretreatments on membrane filtration for a surface water in Korea: A pilot study

Application of membrane filtration has been significantly expanded throughout the world in two decades. A project was launched to facilitate the application of membrane filtration in drinking water plants in Korea in 2004. Five pilot plants each with a capacity of 500 m³/d were installed in a Gueui Drinking Water Plant. The Han River water was a main raw water source for the plants. Key parameters of the raw water were examined. The raw water characteristics are tremendously varied with seasons and rain fall, especially in terms of turbidity and algae numbers. The operation of pretreatment was of substantial importance due to the variation of the raw water. Coagulation and powdered activated carbon adsorption were performed as pretreatment options of microfiltration. The coagulant doses were optimized with increasing turbidity compared to the conventionally used operational manual. PAC adsorption was applied to overcome fouling by high algae numbers. The addition of PAC relieved the aggravation of fouling. However, the PAC addition could not stop the undergoing fouling. A set of laboratory experiments showed that the removal of floc aggregates after coagulation and PAC was critical to maintain high water flux in the membrane system.     

Performance evaluation and mathematical modelling of granular activated carbon biofiltration in wastewater treatment

Biological filtration is an effective technique for removing organic matter from wastewater. The performance of a biofilter can be influenced by a range of operational conditions. In this study the performance of biofilters was investigated for the influence of filter media depth, influent concentrations, filtrations rates and backwashing. The results show that performance of GAC filters decreased with shallower filter bed depths. In addition, the GAC performed better at lower influent concentration and lower filtration rates. The daily backwash adopted to avoid the physical clogging of the biofilter did not have any significant effect on the organic removal efficiency of the filter. The concentration, activity and characteristics of the biomass are quantified and described. A mathematical model was developed to simulate the organic removal of the GAC biofiltration system. The performance of the GAC filter under different influent organic concentration levels, filtration rates and filter bed depths was adequately simulated by the mathematical model developed for this study.