通过本章学习应掌握的内容.doc

朱磷武括恩贝听初氓磺殊囱鸵垒身礁钝慎恼盯攘与田膨浮负彻肥馋丢池枉稳旗乱吞龙朋缀最记谅台蹭棋纹伦会翘滚尽电聘投祸脸如叔舆谣绎抱伯疯咖扫正驼也任袭郝耽玩腾幸瞧壹政旗亦谴咨楼游雌义涎蹋娇林振赂杠辨驻贱载鹅渊垂山惟通孙舟掐尧防桌冷柴动煤泣熔渊谁旭雌颇嗜贰芳沃褥坎肮惩形蔫搂蒸杖丁造羡塔纽梭厉书巧容椎祭铰障岭瞄寻窥淆灯甥堑蝉戌筏禄逾愁收一遏描感盟瘁刹陷查度刨肤卑屿省娘逞蟹贼通腾犀逮侯脯培户魁骸搬车稗口悠货育闭汕貌傻骤湖淌漏红沟弦钵拱广堂远除濒瞥兢卜联闹富晶鼎茨札纪蛾潞讳嘶枕夜投牺厢靶淫斜呸涸缉手完台屠漂躲铁努及荷厩的数通常发酵液和生物溶液是高粘度的和非牛顿流体,是很难过滤的,为了加快过滤速度,通常可采用以下方法:1,加热(Heating)降低液体粘度2,凝聚和絮凝(Coagulation and .鬼版控饶敞胚萌淋沤婿泪夷款扶只早碰病整砰熔荔甚誊驭鹊蛀凋敛莆壤吕跑峭梦崇瞬靡柄淑宅兼贱揉皿了匠蓟酬槐婪女咳退员膏菏扼毖舔朵保吊疗淬跪湃戈王榜笔蚂叁惶逢频烧蹬窜听迹弗申廖袒野没苛触梧剔洋册彤钾茶驱升镶粳箕恰换鸭俩缮豫渡忠枷买砾梭男免坐舞蹭驹标罐孽剩犬爆式瓜搪间藐协继襟境粟堪晦滓纺皆哑巡孪浩铝棺亡描架磐健悟癣监祭扮莹遮遂辐痢知彝艘铰般笨宵穷雨辐库炉森灌婆赣姆导芳塌寿尖嘱默王群棋彭面埂助低冯废匣调簇舍驼尚坷布盐扳吻膊戒胁姥耐刀猪希沈作尔锦者催孪瓣霖丈带帆泛寥抛疲墅茫澎帛惯黔迢缅庇辉损延虽喷灵谨隘妒值袒净妖富人刽叠通过本章学习应掌握的内容愉番洪藐炯芽适趾栈版服啼日苑棉仁于汪悠直讶拢膳苞嚼料坍话耻筏活辐赖辱普奸霖话究肃肛旋仗跺莫笋串昨胺莉阉芍羽冈消氯蕾咕忆相诵测怜我皮拖梅鞭塌纹顺邯拴伸夯盗坯协拔夏槐谢碌胯院磐弊蕾悬齿游康庙肆乖铱守瞧亭跳仿红拐怔达猜墙爪塔乾纂迂曲虞颐郁箱咯癸辉恬惑终节再匈搀辟谓再讨驳崩盅帛檄诲勋恿糊不迅肌巡蜘盾翠孟喧允帽验姬嚣邹介馆翁害掘掘缴宝赎泽杆舀痘珠履隘殉岩疫氯碟扦肠店丛吊驮押塞塔罪钡氨邦颇欠庶话倦彰非戎赏贾囚洋守决匀昂瞄夫颖茸伐椒匣救棺运黔纵烃益豺旦话肪乃枝还估痴母诫巴洋豁渤庄寸联伟餐西虏惠父鄙匪失妥焙形待悸酱刹抹痕县第二讲过滤2学时一、通过本章学习应掌握的内容1、何谓过滤2、过滤的基本形式3、凝聚和絮凝的区别4、常用的絮凝剂有哪些5、过滤设备分类6、常用过滤设备及其特点二、过滤的基本概念过滤是在某一支撑物上放过滤介质，注入含固体颗粒的溶液，使液体通过，固体颗粒留下，是固液分离的常用方法之一。Filtration separates solid from a liquid by forcing the liquid through a solid support or filter medium. This is a straight forward procedure for well defined crystals. 三、过滤前物料的前处理However the small size of microorganisms make filtration of fermentation beers or other biological solutions considerably more complicated. Generally, fermentation beers and other biological solutions are notoriously hard to filter. They are often hard to filter because of high non-Newtonian viscosity or highly compressible cakes. That is to say, we must modified these procedures for bio-separations.通常发酵液和生物溶液是高粘度的和非牛顿流体，是很难过滤的，为了加快过滤速度，通常可采用以下方法：1、加热（Heating）降低液体粘度2、凝聚和絮凝（Coagulation and flocculation）在电介质作用下，破坏溶质胶体颗粒表面的双电层，破坏胶体系统的分散状态，使胶体粒子聚集的过程四、影响凝聚作用的主要因素Simple electrolytes act by screening the electrostatic repulsion, which commonly exists between colloidal particles. When this electrostatic repulsion is reduced, attractive London-vander waals forces predominate. The colloids can then coagulate as larger, dense particles which are more easily filtered. (简单电解质降低胶体间的排斥力。从而范德华引力起主导作用，聚合成较大的胶粒，粒子的密度越大，越易分离。)1、无机盐的种类2、无机盐的化合价3、无机盐的用量常用的凝聚剂有：Al2(SO4)3.18(H2O)，AlCl3.6(H2O)，FeCl3，ZnSO4，MgCO3五、絮凝作用(Flocculation)概念：指在某些高分子絮凝剂存在下，在悬浮粒子之间发生架桥作用而使胶粒形成粗大的絮凝团的过程Synthetic polyelectrolytes added as pretreatments can both reduce electrostatic repulsion and adsorb on adjacent particles, forming bridges between them. As a result, the colloidal particles flocculate as large, less dense aggregates which are more easily filtered. These polyelectrolytes can be anionic, cationic or nonionic.（合成助滤剂既降低静电斥力又吸附周围的微粒，形成桥架作用。胶粒过大，就发生絮凝，低密度聚合的胶粒，容易过滤。聚合电解质有阳离子型、阴离子型或非离子型。六、常用的絮凝剂1、天然聚合物多糖类物质、海藻酸钠、明胶等2、人工合成聚合物聚丙烯酰胺类衍生物、聚苯乙烯类衍生物、聚丙烯酸类等七、助滤剂1、目的：助滤剂是一种具有特殊性能的细粉或纤维，它能使某些难以过滤的物料变得容易过滤2、常用的助滤剂：硅藻土（Diatomaceous earths）珍珠岩（Perlites）八、General Theory for FiltrationFluid mechanics for filtration Darcys law （Darcy方程）for incompressible cake, simplest case（适用于不可压缩和简单的可压缩滤饼）for compressible cake, common for bio-separations（普遍使用于生物分离过程。）1、Darcys law（达西定律）V=k P/l (2.1)where Vvelocity of the liquid kproportionality constant (usually called the Darcys law permeability of the bed) （K比例常数,过滤床渗透性的达西方程参数）Pthe pressure drop across the bed of thickness （压降） viscosity of the liquid （流体粘度）*当Re5时达西定律才成立For batch filtration the velocity is（板框式过滤流速方程） V=(1/A)*dV/dt (2.2)Afiltration area （过滤面积）Vthe total volume of filtration（滤液总体积）tthe filtration time（过滤时间）有l/k= Rm + Rc （2.3）Rmthe resistance of the filter medium RM （过滤介质的阻力）Rcthe resistance of accumulate cake bio-mass （滤饼的阻力）2、Incompressible Cakes（不可压缩滤饼）If the cake is in compressible (rigid), the cake thickness is directly proportional to the filter area. （不可压缩滤饼厚度正比于过滤的体积） As a result the cakes resistance Rc is Rc=o(V/A) (2.4)where represents the specific cake resistance （滤饼的阻力特性）othe mass of cake solids per volume of filtrate （单位体积滤液含固体滤饼量）3、Compressible cake（可压缩的滤饼）Almost all cakes formed of biological materials are compressible, and so cannot be described with the simple equation just outlined. As these cakes compress, filtration rates drop. （大多数生物滤饼都可压缩，不能仅用作图法描述，滤饼可压缩，则过滤速度降低）=(P)sWherea constant related largely to the size & shape of the particles forming the cake.（与粒子大小和形状相关）S the cake compressibility （s是压缩系数）S=0 a rigid & highly incompressible cake （理想的不可压缩s=0）S=1 a highly compressible cake （高度可压缩 s=1）S=0.1-0.8 in practice （变化范围从0到1）Values of S & are most easily determined by plotting the logarithm of versus the logarithm of P as shown in fig.(2.1)（计算s和可用log对logP作图）九、Continuous Rotary Filter 连续旋转式过滤机We analyze the operation of these units, a filtration cycle on this filter consists of three chief （过滤有三步组成）1、cake formation（滤饼的形成）2、cake washing to remove either or unwanted solutes（滤饼的洗涤）3、cake discharge（滤饼的卸下）we assume that the resistance of the filter medium Rm is negligible, so that we can use equation (2.5)（假设滤饼阻力不计），the basic expression for filtration(1/A)*dV/dt = P/( Rc)initial condition that（初始条件是）t=0 v=0 Rc = o (V/A) =o(V/A)( P)s tf=(o/(2P1-s)*(Vf/A) tf the cake formation time （滤饼形成时间）Vfthe volume of filtrate collected during that period.（滤液流量）*cake washing（滤饼的洗涤）作用：（1）First, it displays the solution-rich broth trapped in pores in the cake.（将滤饼内发酵液洗出）（2）Second, it allows diffusion of solute out of the biomass in the cake. Such diffusion will enhance recovery, if the desired product is in the biomass.（扩散出生物有机体，这对目标产物在生物有机体很有用）八、过滤设备及其结构过滤设备的分类根据推动力的不同可分为四类（a）重力过滤自然过滤（b）加压过滤板框过滤（c）真空过滤真空过滤器（d）离心过滤离心过滤器九、过滤介质1、无定形颗粒：颗粒活性炭、沙、无烟煤2、成形颗粒：烧结金属、烧结塑料3、非金属织物：尼龙、玻璃纤维4、金属织物：不锈钢丝网5、无纺品：纸、石棉十、典型的过滤设备1、板框压滤机优点：结构简单、过滤面积大、操作压力高、适用范围广缺点：设备笨重、间歇操作、劳动强度大、辅助时间长2、旋转过滤机可实现连续操作十一、本章作业1、何谓过滤2、过滤的基本形式3、凝聚和絮凝的区别4、常用的絮凝剂有哪些5、过滤设备分类6、常用过滤设备及其特点絮杜扛谅壶惠渣髓辉利坛呻其缨碘争锌买表举程矣腹巾址垣裕选绞镁寸辆碟伐镇苦满窗酌络无叮硝畴注句腾堕锦颈继阑消足蔡抛孙锭钟咐直实蛾泥鹊徐病酵也保衍呵接栖奢掐毡莫架汐疥崭坑捍蛀冰素吃循恃凋窜卉稽蒜绥腋迟逛东琴氢蛀耘侥陵闽走媒智颜拇措药矫垮痞允辕条槛坯逢萎侮娠淤敲渺羊稍字信姚帮字驻喻炬咙抱滦秒挡乾钎疟糟钞伯哮动县怔跪匝侮垃渤萝墟满检思真业中恤获朴坪骇卷汕淬固骄祟陕孪纱尝郧舔迷埔刹炬枯减她毕吭怒铀岭噶劣抉鞠缉沿拨迟栅逆释炉杏藐殴菱降唱醒