化工专业英语一课件市公开课一等奖省赛课微课金奖PPT课件.pptx

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,2021/10/3,#,Specialized English for chemistry,化工专业英语,化工专业英语一课件,第1页,1/35,Chemical Enineering and Technology,Lesson 3 Catalysts for Industrial Processes,The,criteria,for an industrially successful catalyst are very,stringent.,Criteria （批评、判断等）标准，准则(criterion名词复数,Stringent adj.严格;迫切;（货币）紧缩,The two most important considerations are,activity,and,durability;suitability,for basic study is not a factor,and this has,retarded,progress in our understanding of how such technical catalysts really operate.,化工专业英语一课件,第2页,2/35,Let us consider the two,prime,requirements.,prime adj.最好;首要;最初;基本,n.精华;早期;全盛时期;青年 vt.使准备好;填装;事先指导,First,the catalyst must be able to effect the desired reaction at an acceptable rate under conditions of temperature and pressure that are practicable.,化工专业英语一课件,第3页,3/35,Chemical technology has advanced to the point where temperatures as high as 1600K and pressure up to 350 atm(35MPa)present no difficulties and,thermodynamic,considerations sometimes,necessitate,their use to attain reasonable,equilibrium,yields of products.,Necessitate vt.使成为必要，需要;强迫，迫使,equilibrium n.平衡，均势;平静,化工专业英语一课件,第4页,4/35,If however good yields can be obtained at low temperatures and pressures,then there is every,incentive,to find a catalyst that will operate under the,mildest,possible conditions,since the use of,extreme,conditions is very,costly,.,Incentive n.动机;刺激;诱因;勉励 adj.刺激性;勉励性质,Mildest 适当 适中,It is,concurrently,important that,side-reactions,are,minimal,especially those leading to,poisoning,or,deactivation,through,carbon deposition,.,化工专业英语一课件,第5页,5/35,Second,the catalyst must be able to sustain the desired reaction over,prolonged,periods:in some processes,a catalyst life of several years is not uncommon,and is economically necessary.,Prolong vt.延长，拉长;拖延，延期,Clearly the longer it lasts,the smaller the contribution that its,initial,cost makes to the overall cost of the process will be.,initial adj.最初;开始;首字母,化工专业英语一课件,第6页,6/35,Initial cost is rarely of,over-riding,importance:it is usually cheaper in the long run to use an expensive catalyst that will last a long time than a cheap one that has to be replaced frequently.,The chief causes of,deterioration,in use are:,reversible poisoning,due to impurities in the reactants or to side-reactions,and,irreversible,physical changes including loss of surface area(,sintering,)or mechanical failure.,Deterioration n.恶化;变坏;退化;堕落,Irreversible adj.不可逆;不能翻转;不能倒置,sintering n.泉华，烧结物，熔渣 vt.使烧结,化工专业英语一课件,第7页,7/35,Reversible poisoning,may with luck be,rectified,by simple treatment,such as,oxidation,or washing,without removing the catalyst from the reactor.,Rectified adj.医矫正，调整,v.更正，矫正(rectify过去式和过去分词);精馏,To,guard,against physical changes,careful attention has to be given to the strength of the catalyst.,guard n.警卫;狱吏，看管;护卫队;防护装置,vt.保卫，守护;看管;加防护装置;慎重使用,vi.警觉;警卫,化工专业英语一课件,第8页,8/35,The preferred physical form for a catalyst is determined entirely by the manner in which it is to be used.,Its particle size is especially fixed,at least,within broad limits,by the type of reactor to be employed.,A rough,criterion,is whether or not one can,distinguish,separate particles with the,naked eye,.,Criterion n.（批评、判断等）标准，准则;规范,When the reactants are,solely,gases or vapors,there are only two possible basic types of reactor that can be used.,solely adv.唯一地;仅仅;独一无二地;纯粹,化工专业英语一课件,第9页,9/35,When the,reactants,are,solely,gases or vapors,there are only two possible basic types of reactor that can be used.,solely adv.唯一地;仅仅;独一无二地;纯粹,Fixed-bed reactor,Fluidized-bed reactor,化工专业英语一课件,第10页,10/35,Tubular reactor,kettle reactor,化工专业英语一课件,第11页,11/35,Packed tower reactor,Tower reactor,化工专业英语一课件,第12页,12/35,A fixed-bed reactor,is one in which a tube is packed with“,coarse,”catalyst particles through which the reactants flow.,Coarse adj.粗鄙;粗糙;粗野;粗制滥造,As a result of,the obstruction to gas flow by the particles,a pressure drop,occurs across the bed,and,a positive pressure,has to be applied at the inlet to secure an adequate,flow-rate,.,化工专业英语一课件,第13页,13/35,The size of the pressure drop incrases with increasing flow-rate and bed length,and with decreasing particle size.,Many different shapes and sizes of catalyst particles are used in fixed-bed reactors,and a great deal of skill and experience goes into choosing the most,appropriate,for a,given,set of conditions.,appropriate adj.适当;恰当;适当,v.盗用;侵吞;拨（专款等）,化工专业英语一课件,第14页,14/35,Spherical,Trifolium,Cylindrical,Saddle,化工专业英语一课件,第15页,15/35,Dimensions,of more common forms are usually between 2mm and 2cm.,Dimensions vi.按规格尺寸切割 vt.在上标尺寸,n.面积;特点;（长、宽、厚、高等）尺寸;主要性;尺寸(dimension.,When,as,in the case of,ammonia,oxidation,it is desired to use a pure metal catalyst at high temperature and a very short time.,Ammonia n.氨;氨水;氨气,化工专业英语一课件,第16页,16/35,So a bed of 20 to 30,finely,woven,metal,gauges,is used,this is another catalyst form suited for use in a fixed-bed reactor.,Woven v.编，织，织成(weave过去分词);编排;杜撰;（把）编成,gauges n.测量标准或范围;尺度，标准;测量仪器;评定,vt.（用仪器）测量;确定容量，体积或内容;评定，判断;采取,化工专业英语一课件,第17页,17/35,Since many catalyzed reactions are strongly,exothermic,fixed-bed reactors must contain a facility for removing the unwanted,enthalpy,of reaction.,exothermic adj.发烧，放出热量,Enthalpy n.热焓;物热函;热含量,H,Jacket,Snake tube,Tubular heat exchanger,化工专业英语一课件,第18页,18/35,This may be done in one or two ways.,A multi,tubular,reactor contains a large number of reaction tubes,typically 2.5 cm in diameter,with a cooling gas or liquid flowing between them.,tubular adj.管系组织;管子形，管状;管子做成;发吹管般声音,化工专业英语一课件,第19页,19/35,Alternatively,the bed may be,split into,sections,with provision for cooling the gas in the spaces between.,Alternatively adv.二者择一地;要不然;或者,Intermediate indirect heat transfer,Q,uenching with feed gas,化工专业英语一课件,第20页,20/35,A further important and quite different catalyst form is finding application,especially in air-pollution control.,This is the,so-called,monolithic,structure,which consists of a block of,ceramic,material(-,alumina,or,mullite,),through which runs fine,parallel,channels.,monolithic adj.独块巨石;整体;庞大,Ceramic dj.陶器，与陶器相关;陶瓷，陶制;制陶 n.陶瓷制品;陶瓷器;制陶艺术;陶瓷装潢艺术,alumina n.氧化铝，矾土;铝土 Mullite n.多铝红柱石;莫来石,parallel adj.平行;相同，类似;电并联;计并行,化工专业英语一课件,第21页,21/35,The structures can be made in many different ways,each of which results in a,characteristic,channel shape.,The blocks are obtainable,in a range of,shapes and sizes,and a single block when inserted in a container therefore behaves as a fixed-bed reactor.,化工专业英语一课件,第22页,22/35,Because of the low,porosity,of the material from which these structure are made,it is usually necessary to attach a thin layer of a more porous substance to which the catalytically active phase can,adhere.,porosity n.多孔性，有孔性,Adhere vi.黏附;附着;坚持;追随 vt.使粘附;遵照，坚持;追随，依附,化工专业英语一课件,第23页,23/35,Such,monolithic,structures have several clear advantages over,pellets,or,granules,packed,loosely,in a tube.,Monolithic adj.独块巨石;整体;庞大,Pellets n.小球;小子弹;石弹，炮弹;（货币等）圆浮雕,v.用小球扔;用子弹射击;将制成丸状;把弄成小球形,granules n.小颗粒，小硬粒(granule名词复数),化工专业英语一课件,第24页,24/35,First,the pressure drop,through the bed is less for equal quantities of catalyst,thus permitting higher space,velocities,to be achieved;,Velocities n.速度(velocity名词复数);高速，快速,化工专业英语一课件,第25页,25/35,secondly,there is no,attrition,of the catalyst,due to,particles,rubbing,against each other and forming,fine dust,.,Attrition n.消耗;消磨;摩擦;（神学）不彻底忏悔,Rubbing n.拓本，拓印,fine dust 细粉尘;纤尘,化工专业英语一课件,第26页,26/35,Their ability to,withstand,thermal shock,is however in some cases limited.,Withstand vt.经受，承受，禁得起;反抗,vi.反抗;耐得住，禁得起,The second basic kind of reactor for,gaseous,reactions is,the fluidized bed,.,Gaseous adj.气态，似气体;无实质;美俚不可靠;气性,化工专业英语一课件,第27页,27/35,Here the catalyst consists of fine particles.,And when,the gas flow,upwards through a bed,such powder attaining a,critical,velocity,the bed appears to“boil”:it expands,significantly,and the particles are in continuous motion.,Critical adj.批评，爱挑剔;关键;严重;极主要,Velocity n.速率，速度;周转率;高速，快速,化工专业英语一课件,第28页,28/35,In this state the bed is said to be,fluidized,.,Fluidized adj.流态化，沸腾,v.使液化，流（态）化(fluidize过去式和过去分词),化工专业英语一课件,第29页,29/35,The behavior gives certain advantages over fixed beds,for example,heat transfer,characteriatics are much better,and,the pressure drop,increases far less quickly with increasing,flow-rate.,化工专业英语一课件,第30页,30/35,Exercises,Vocabulary,1 Cataysts are substances which by their,mere,presence,evoke,chemical reaction.,A change B impede C fortify D cause,2 The,essence,of catalysts is not the entering but the,falling out,.,A reaction B consumption C departure D appearance,3 In practice this definition proves too,restrictive.,A board B activated C vague D specific,化工专业英语一课件,第31页,31/35,4 A catalyst is generally not,used up,itself in a chemical reaction.,A required B activated C consumed D energetic,5 The,activation energy,barrier must be,surmounted,for reaction to take place.,A conquered B permitted C removed D determined,6 Catalysts that,accelerate,hydrolysis,of,esters,must also accelerate esterification of alchols.,A proceed B develop C fasten D chain,化工专业英语一课件,第32页,32/35,7 A,distinction,is made between,homogeneous,catalysts and heterogeneous catalysis.,A comparison B difference C decision D proportion,8 A new reaction,mechanism,permits the reaction to occur,via,a different activated complex.,A through B within C beyond D outside,化工专业英语一课件,第33页,33/35,Fill in the blanks with the following phrases.,use up,be referred to as,fall out,in practice,in terms of,be provided with,make a distinction between,1 The leader of the team was glad to find that not a single man()in the long march.,2 Your idea seems quite appealing,but it wont work().,3 The incident which took place during the weekend()political.,4 The teacher asked the student to explain the sentence()grammar.,5 The student in this school()food and books.,6 To his surprise,all his money had been()before the end of his journey.,7 The professor asked the student to()American English and British English.,化工专业英语一课件,第34页,34/35,翻译,1,The process of increasing the rate of a reaction through the use of a catalyst which is not used up itself in the reaction is referred to as catalysis.,2,The essence of catalysts is not the entering but the falling out.,3,A catalyst is a substance that changes the velocity of a chemical reaction without itself appearing in the end products.,4,This usually means that the reaction mixture is liquid or gaseous and the catalyst solid.,化工专业英语一课件,第35页,35/35,