《《专业英语阅读》PPT课件.ppt》由会员分享，可在线阅读，更多相关《《专业英语阅读》PPT课件.ppt（20页珍藏版）》请在金锄头文库上搜索。
1、Unit 2 Reaction Engineering May25th,2011YingXiaoguangLesson 1 Reactor Typesuu11StirredtankreactorStirredtankreactoruuAAbatchstirredtankreactorbatchstirredtankreactoristhesimplesttypeofisthesimplesttypeofreactor.Itiscomposedofareactorandamixerreactor.Itiscomposedofareactorandamixersuchasasuchasastirr
2、erstirrer,a,aturbinewingturbinewingoraorapropellerpropeller.The.Thebatchstirredtankreactorisillustratedbelow:batchstirredtankreactorisillustratedbelow:enzaim uu ThebatchsystemisgenerallysuitablefortheThebatchsystemisgenerallysuitablefortheproductionofrathersmallamountsofchemicals.productionofrathers
3、mallamountsofchemicals.uuAAcontinuousstirredtankcontinuousstirredtankreactorisshownbelow.reactorisshownbelow.uuThecontinuousstirredtankreactorismoreThecontinuousstirredtankreactorismoreefficientthanabatchstirredtankreactorbuttheefficientthanabatchstirredtankreactorbuttheequipmentisslightlymorecompli
4、cated.equipmentisslightlymorecomplicated.uu22TubularReactorTubularReactor uuTubularreactorsTubularreactorsaregenerallyusedforgaseousreactions,aregenerallyusedforgaseousreactions,butarealsosuitableforsomeliquid-phasereactions.butarealsosuitableforsomeliquid-phasereactions.uuIfhighheat-transferratesar
5、erequired,small-diameterIfhighheat-transferratesarerequired,small-diametertubesareusedtotubesareusedtoincreasethesurfaceareaincreasethesurfaceareatovolumeratio.tovolumeratio.uuSeveraltubesmaybearrangedSeveraltubesmaybearrangedinparallelinparallel, ,connectedtoaconnectedtoamanifoldmanifold( (多支管多支管多支
6、管多支管)orfittedintoa)orfittedintoatubesheettubesheetinasimilararrangementtoashellandinasimilararrangementtoashellandtubeheatexchanger.tubeheatexchanger.uuForhigh-temperaturereactionsthetubesmaybeForhigh-temperaturereactionsthetubesmaybearrangedinafurnace.arrangedinafurnace.uu33FluidizedbedFluidizedbed
7、ReactorReactoruuAfluidizedbedreactorAfluidizedbedreactor( (FBRFBR)isatypeof)isatypeofreactordevicethatcanreactordevicethatcanbeusedtocarryoutabeusedtocarryoutavarietyofmultiphasevarietyofmultiphasechemicalreactions.chemicalreactions.uuInthistypeofreactor,afluid(gasorliquid)isInthistypeofreactor,aflu
8、id(gasorliquid)ispassedthroughagranularsolidmaterial(usuallypassedthroughagranularsolidmaterial(usuallyacatalystpossiblyshapedastinyspheres)athighacatalystpossiblyshapedastinyspheres)athighenoughvelocitiestosuspendthesolidandcauseitenoughvelocitiestosuspendthesolidandcauseittobehaveasthoughitwereafl
9、uid.tobehaveasthoughitwereafluid.uuThisprocess,knownasfluidization,impartsmanyThisprocess,knownasfluidization,impartsmanyimportantadvantagestotheFBR.importantadvantagestotheFBR.uuAsaresult,thefluidizedbedreactorisnowusedAsaresult,thefluidizedbedreactorisnowusedinmanyindustrialapplications.inmanyindu
10、strialapplications.Unit 3 BiochemistryuuBiochemistry is the study of the chemical processes in living organisms. It deals with the structure and function of cellular components, such as proteins, carbohydrates, lipids, nucleic acids, and other biomolecules.uuThe term carbohydrate reflects the fact t
11、hat many of the compounds in this category have the empirical formula (经验式) CH2O.uuCarbohydrates are the primary source of food energy for most living systems.uuThey include simple sugars such as glucose (C6H12O6) and sucrose (C12H22O11) as well as polymers of these sugars such as starch, glycogen,
12、and cellulose. uuCarbohydrates are produced from CO2 and H2O during photosynthesis and are therefore the end products of the process by which plants capture the energy in sunlight. uuLipids, on the other hand, are defined on the basis of their physical properties. uuAny molecule in a biological syst
13、em that is soluble in nonpolar solvents is classified as a lipid. uuThe lipid known as cholesterol, for example, is virtually insoluble in water, but it is soluble in a variety of nonpolar solvents including the nonpolar region between the inner and outer surfaces of a membrane. uuThe name The name
14、nucleic acidnucleic acid was originally given to a was originally given to a class of relatively strong acids that were found in class of relatively strong acids that were found in the nuclei of cells. the nuclei of cells. uuAs monomers, nucleic acids such as adenosine As monomers, nucleic acids suc
15、h as adenosine triphosphatetriphosphate (ATP) are involved in the process (ATP) are involved in the process by which cells capture food energy and make it by which cells capture food energy and make it available to fuel the processes that keep cells available to fuel the processes that keep cells al
16、ive. alive. uuAs polymers, they store and process the As polymers, they store and process the information that allows the organism to grow and information that allows the organism to grow and eventually reproduce. eventually reproduce. uuAlthough there are a vast number of different Although there a
17、re a vast number of different biomoleculesbiomolecules, many are , many are complex and large complex and large moleculesmolecules (called polymers) that are composed (called polymers) that are composed of similar repeating subunits (called monomers). of similar repeating subunits (called monomers).
18、 uuEach class of polymeric Each class of polymeric biomoleculebiomolecule has a has a different set of different set of subunit typessubunit types. . uuFor example, a protein is a polymer whose For example, a protein is a polymer whose subunitssubunits are selected from a set of 20 or more are selec
19、ted from a set of 20 or more amino acids. amino acids. uuBiochemistry studies the chemical properties of Biochemistry studies the chemical properties of important biological molecules, like proteins, in important biological molecules, like proteins, in particular the chemistry of particular the chem
20、istry of enzyme-catalyzedenzyme-catalyzed reactions. reactions. DNAuuThe The biochemistry biochemistry of cell metabolism and the of cell metabolism and the endocrine(endocrine(内分泌内分泌) system has been extensively ) system has been extensively described. described. uuOther areas of biochemistry inclu
21、de the genetic Other areas of biochemistry include the genetic code (DNA, RNA), protein synthesis, cell code (DNA, RNA), protein synthesis, cell membrane transport, and signal transduction.membrane transport, and signal transduction.uuDNA structure uuDeoxyribonucleic acid (DNA) is a nucleic acid tha
22、t contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. uuThe main role of DNA molecules is the long-term storage of information. uuDNA is often compared to a set of blueprints(蓝图) or a recipe(药方), or a code, since it contains the i
23、nstructions needed to construct other components of cells, such as proteins and RNA molecules. uuThe DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information. uuChemically, D
24、NA consists of two long polymers Chemically, DNA consists of two long polymers of simple units called nucleotides(of simple units called nucleotides(核苷酸核苷酸), with ), with backbones made of sugars and phosphate backbones made of sugars and phosphate groups joined by ester bonds. groups joined by este
25、r bonds. These two strands(These two strands(链链) run ) run in opposite directions to in opposite directions to each other and are each other and are therefore anti-parallel. therefore anti-parallel. Attached to each sugar is Attached to each sugar is one of four types of one of four types of molecul
26、es called bases.molecules called bases.uuIt is the sequence of these four bases along the backbone that encodes(编码) information. uuThis information is read using the genetic code, which specifies the sequence of the amino acids within proteins. uuThe code is read by copying stretches(伸展的形态) of DNA i
27、nto the related nucleic acid RNA, in a process called transcription.uuWithin cells, DNA is organized into Within cells, DNA is organized into structures called chromosomes.structures called chromosomes.uu These chromosomes are duplicated These chromosomes are duplicated before cells divide, in a pro
28、cess called DNA before cells divide, in a process called DNA replication. replication. Eukaryotic(Eukaryotic(真核真核) ) organisms organisms (animals, plants, fungi(animals, plants, fungi菌类菌类, , and and protistsprotists原生生物原生生物) store their ) store their DNA inside the cell nucleus, DNA inside the cell
29、nucleus, whilewhile in prokaryotes ( in prokaryotes (原核原核) )(bacteria and (bacteria and archaearchae) ) it is found in the cells cytoplasm.it is found in the cells cytoplasm. uuWithin the chromosomes, chromatin (染色质) proteins such as histones (组蛋白) compact and organize DNA. uuThese compact structure
30、s guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed(转录).PronteinuuA protein is a biological polymer comprising A protein is a biological polymer comprising ( (由由构成；包含构成；包含)numerous amino acids )numerous amino acids linked recursively(linked
31、 recursively(递进递进) through peptide ) through peptide bonds between a carboxyl group and an bonds between a carboxyl group and an amino group of adjacent amino group of adjacent 相邻相邻 amino acids amino acids to form a long chain with the defining side to form a long chain with the defining side group
32、of each amino acid protruding from group of each amino acid protruding from it. it. uuThe sequence of amino acids in a protein is The sequence of amino acids in a protein is defined by a gene and encoded in the defined by a gene and encoded in the genetic code, which selects protein genetic code, which selects protein components from a set of 20 “standard” components from a set of 20 “standard” amino acids.amino acids.
