水蒸汽加热苯甲苯混合液卧式列管换热器的设计[1]

1、rehabilitation training, because at that time the city has not specifically for deaf children of professional rehabilitation agencies, she will accept rehabilitation training must go to suzhou, due to her age is too small must take care of their parents, her mother had to resign to suzhou to take ca

2、re of her, thus to their family brought two problems, one is the economic pressure, second, children are in the most need caring parents feel term age and father separated, unable to feel the happy family to grow. in order to avoid more and more families appear this kind of circumstance, actively co

3、ordinating the city fimitic established rehabilitation center, operation center for the xx membership received rehabilitation training of special children and parents brought great convenience, to enable them to the nearest and handy to get high-quality rehabilitation services, huimin policy of the

4、communist party of china has been fully reflected.regular organization of the fast forward, three special children into society. due to the special childrens own disability, they rarely and social contact, we hope that in their rehabilitation training can have more opportunities to integrate into so

5、ciety, by the municipal cdpf coordination has been relevant departments of the strong support, promote the special children into social work: one is the municipal cdpf and city bureau of education in training children rehabilitation assessment, 2015 years 3 hearing-impaired children get a rehabilita

6、tion of the good results, enter the ordinary kindergarten and primary school; the second is the city library volunteer monthly to center on childrens stories, playing games and other entertainment activities, into a step broaden their way of thinking; the third is under the support of the city board

7、 of education, the center will and yanshan mountain kindergarten cooperation, fusion education project weekly by the special education teacher lead 1-2 hearing-impaired children into yanshan mountain kindergarten accept half a day of kindergarten education, let children with special filling feeling

8、kindergarten learning atmosphere, for their future access to kindergarten and primary school lay a solid foundation., handicap love, care for children with special. caring for children with special needs to let them with healthy children as happy growth but also our work direction: one is actively c

9、ontact the society from all walks of life of the difficulties children with special care and support this year in coordination with the city fimitic, ningbo bank co., ltd. xx branch president assistant zhao yi for a row represents dandelion love fund to in the center received rehabilitation training

10、 of xu yang and xu miao brother and sister to send two of the loving enterprises special care; the second is actively contact the love team and community volunteers to the children in the center to all kinds of theatrical performances and interactive games, let them enjoy the happiness in the activi

11、ties, and further enrich the their spiritual and cultural life.five, increase the propaganda of rehabilitation services, and further enhance the sense of rehabilitation. in the suburbs especially in rural areas, to disabled学 号 0120920400335课程设计 题 目水蒸汽加热苯-甲苯混合液卧式列管换热器的设计 学 院 化学工程学院 专业班级 制药0903 姓 名 指导

12、老师 2011年 8月课程设计任务书学生姓名： 刘丽娜 专业班级： 制药0903班 指导教师： 工作单位： 化学工程学院 题 目: 水蒸汽加热苯-甲苯混合液卧式列管换热器的设计 初始条件：设计一台卧式列管换热器，将质量流量为80吨/小时的苯-甲苯（x1=0.4）混合液从20加热到94，加热介质采用300kpa绝压的饱和水蒸汽，冷凝液在饱和温度下排出，要求换热器的管程压降小于70kpa。要求完成的主要任务: （包括课程设计工作量及其技术要求，以及说明书撰写等具体要求）1、合理的参数选择和结构设计；2、工艺计算，包括传热计算和压降计算等；3、主要设备工艺尺寸设计。时间安排：设 计 内 容所用时间1

13、、根据换热任务和有关要求确定设计方案；1天2、初步确定换热器的结构和尺寸； 1天3、核算换热器的传热面积和流体阻力；1天4、确定换热器的工艺结构；1天5、写出设计说明书。1天指导教师签名： 年 月 日系主任（或责任教师）签名： 年 月 日目录设计任务书2绪论4符号说明7工艺计算8 确定物性数据8 确定计划方案9 计算总传热面积9 工艺结构尺寸10 换热器核算10设计数据结果一览表15结束语16参考文献17绪论一、列管式换热器的结构和特点管壳式换热器(shell and tube heat exchanger)又称列管式换热器。是以封闭在壳体中管束的壁面作为传热面的间壁式换热器。这种换热器结构较

14、简单，操作可靠，可用各种结构材料（主要是金属材料）制造，能在高温、高压下使用，是目前应用最广的类型。 根据冷热流体换热方式的不同可将换热器分为混合式换热器、蓄热式换热器和间壁式换热器。其中以间壁式换热器应用最为广泛，型式也最为多样。按换热器传热面形状和结构的特点，间壁式换热器又可分为管式换热器、板式换热器和特殊式换热器三类。列管式换热器是化工生产中常用的一种换热设备, 结构简单, 适应性强; 单位体积所具有的传热面积大并传热效果好; 而且种类多, 型号全。列管换热器主要特点： 1、耐腐蚀性：聚丙烯具有优良的耐化学品性，对于无机化合物，不论酸，碱、盐溶液，除强氧化性物料外，几乎直到100都对其无

15、破坏作用，对几乎所有溶剂在室温下均不溶解，一般烷、径、醇、酚、醛、酮类等介质上均可使用。2、耐温性：聚丙烯塑料熔点为164-174，因此一般使用温度可达110-125。3、无毒性：不结垢，不污染介质，也可用于食品工业。4、重量轻：对设备安装维修极为方便。二、管壳式换热器的选用和设计计算步骤1、浮头式换热器结构 换热器的一块管板用法兰与外壳相连接，另一块管板不与外壳连接，以使管子受热或冷却时可以自由伸缩，但在这块管板上连接一个顶盖，称之为“浮头”，所以这种换热器叫做浮头式换热器。其优点是：管束可以拉出，以便清洗；管束的膨胀不变壳体约束，因而当两种换热器介质的温差大时，不会因管束与壳体的热膨胀量的

16、不同而产生温差应力。其缺点为结构复杂，造价高。浮头式换热器，管束一端的管板可自由浮动，完全消除了热应力;且整个管束可从壳体中抽出,便于机械清洗和检修。浮头式换热器的应用较广，但结构比较复杂，造价较高。 浮头式换热器2、试算初步选设备规格确定流体在换热器中的流动途径。附表一附表一 列管式换热器易燃、易爆液体和气体允许的安全流速液体名称乙醚、二氧化碳、苯甲醇、乙醇、汽油丙酮氢气安全流速，m/s123108根据传热任务计算热负荷q。确定流体在换热器两端的温度，选择管壳式换热器的类型；计算定性温度，并确定在定性温度下的物体物性。计算平均温度差，并根据温度校正系数不小于0.8的原则，决定壳程数。依据总传

17、热系数的经验值范围，选定总传热系数k。由初步算出s，并确定换热器基本尺寸。 换热管规格和排列选择换热管直径越小，换热器单位容积的传热面积越大。因此对于洁净的流体可完管径可取得小些。但对于不洁净或易结垢的流体，管径应取的大些，以免堵塞。为了制造和维修的方便，我国目前试行的系列标准规定采用f192mm和f252.5mm两种规格，管长有1.5、2.0、3.0、6.0m，排列方式：正三角形、正方形直列和错列排列，见下图。各种排列方式的优点：3、计算管程，壳程压强降 初步计算管程，壳程流体的流速和压强降，检查结果是否合理，满足工艺要求。若压强降不符合要求，再确定管程数或折流板间距，或重新调整流速，再确定

18、各种尺寸，直到压降满足要求为止。4、核算中传热系数根据流体性质选择适当的垢层热阻r，由r、和计算，再由传热基本方程计算。当小于初选换热器实际所具有的传热面积，则计算可行。考虑到所用换热器计算式的准确度及其他未可预料的因素，应使选用换热器面积有15%25%的裕度，即=1.151.25，否则应重新估计一个，重复以上计算。 符号说明office.children are in need of early detection, early intervention. early rehabilitation concept is relatively weak, is generally believ

19、ed that developing children behind with the growth of the age will continue to improve, to increase the propaganda of rehabilitation policy and the concept of rehabilitation is crucial. for this center to increase efforts to promote the relentless efforts: is to assist the city fimitic in national e

20、ar care day national helping the disabled day during major festivals held special rehabilitation knowledge lectures, rehabilitation policy and rehabilitation concept and a series of publicity activities; the second is on a monthly basis to carry out parent training and rehabilitation guidance into t

21、he family and other rehabilitation services. two regulations promulgated in party power for a long time and under the condition of governing the country according to law, implement the full strictness of strategic deployment, implementation by board trustee administering the party and strengthen the

22、 inner-party supervision of major initiatives. two rules match, the guidelines adhere to the positive advocacy, lide, party members and cadres to visible, reach the high standards; around discipline cracked the requirements of the regulations, set out a negative list, and focus on state control, whi

23、ch gives the party organizations and party members out of the bottom line. the following, mainly from four to two party rule interpretation: first part of both necessity and process of legislative changes within the party; part two interpretation of legislative changes within the party principles of

24、 part two of regulation within the party after the third major change and several key issues need part on how well the two implementation of inner-party regulations. a, the guidelines and the regulations of the need for revision and revision process of central committee of cpc party members and lead

25、ing cadres honesty in politics a number of amendments to the guidelines and the chinese communist party disciplinary regulations classified as 2015 1 the focus of strengthening the construction of partys laws and regulations. two party rule revisions last year, centralized the party wisdom, gather c

26、onsensus, learn from historical experience, respect for wisdom, reflecting the unity of inheritance and innovation; follow the correct direction and seize the limited objectives, uphold the partys leadership, people, centered on solving problems. new standards and regulations, as amended, and reflec

27、ts the partys 18 and 18 in the third, four in the plenary session, reflects the experience of studying and implementing the xi series of important speech, general secretary, reflects the partys 18 since the comprehensive practice of strictly administering the party. (a) the need to amend the two reg

28、ulations in the party of the code was in 1997 the cpc party members and leading cadres honesty in politics a number of standards (for trial implementation) revised on the basis of which, published in january 2010, on strengthening the construction of leading cadres play an important role. but with t

29、he deepening of the party controls the party, strictly administering the party, has been unable to fully adapt to the needs. a is content had fan, 8 a ban, and 52 a no to remember, and also to practice line; ii is gel refining positive advocate insufficient, ban sex terms too much, no reflected self

30、-discipline of17英文字母b折流板间距，m;c系数，无量纲；d管径，m；d换热器外壳内径，m；f摩擦系数；f系数；h圆缺高度；k总传热系数，w/（m2）；l管长，m；m程数；n指数； 管数； 程数；n管数； 程数；nb折流板数；nu努赛尔准数；p压力，pa； 因数；pr普兰特准数；q热通量，w/m2；q传热速率，w；r半径，m； 气化热，kj/kgr热阻，m2/w 因数；re雷诺准数；s传热面积，m2；t冷流体温度，； 管心距，m；t热流体温度，；u流速，m/s；w质量流量，kg/s。希腊字母对流传热系数，w/(m)有限差值；导热系数，w/(m)；粘度，pas；密度，kg/m3；

31、校正系数。下标i管内；m平均；o管外；s污垢。工艺计算一、确定物性数据定性温度：可取流体进出口温度的平均值壳程水蒸汽温度的定性温度为（300kpa绝压下的水蒸汽t=133.3）管程流体的定性温度为=根据定性温度，分别查取有关物性数据水蒸汽在133.3下的有关物性数据如下密度 =1.651 kg/m3定压比热容 =1.9735 kj/(kg)导热系数 =0.0265971 w/(m)黏度 =1.33105 pas液化热 =2168.1kj/kg苯-甲苯混合液（x1=0.4）在57下的物性数据如下密度 =834.5295716 kg/m3定压比热容 =1.686 kj/(kg)导热系数 =0.12

32、3438163 w/(m)黏度 =3.93104 pas二、确定计划方案选择换热器类型 两流体温度变化情况：热流体（水蒸汽）进口温度133.3，出口温度133.3；冷流体（苯-甲苯）进口温度20，出口温度94。估计管壁温和壳壁温之差较大，再加上所受压力较大，因此选用浮头式换热器。流动空间及流速的确定由于饱和蒸汽宜走壳程，饱和蒸汽比较清洁，而且冷凝液容易排出；苯-甲苯混合液走管程。三、估计总传热面积热流量水蒸汽流量平均传热温度传热面积，根据流体情况，假设四、工艺结构尺寸由浮头式（内导流）换热器的基本参数表*查得壳径/mm700管子尺寸/mmf252.5mm公称压强/mpa2.5管长/m4.5公称

33、面积92.1管子总数268管程数2管子排列方法正方形斜转45若选用该型号换热器，则要求过程的总传热系数为五、换热器核算1、核算压强降管程流动阻力管程阻力等于流体流经传热管直管阻力和管程局部阻力之和。即 为管程结垢校正系数，量纲为1，对f252.5mm的管子可近似取1.4。*化工原理上册，2）浮头式（内导流）换热器的基本参数，天津大学出版社2005年版，第367页。管程流体通截面积管程流体流速设管壁粗糙度，查图*得所以 管程流动阻力小于70kpa，符合设计条件。 2、热流量核算壳程对流传热系数蒸汽在水平管束外冷凝，可采用凯恩（kern）估算式，根据两流体温度与传热系数，假设tw=115管程对流传

34、热系数*化工原理上册，图1-27 摩擦系数与雷诺准数及相对粗糙度的关系，天津大学出版社2005年版，第54页。普兰特准数传热系数k查表*知污垢热阻，管壁导热系数 故此换热器合适。*化工原理上册，壁面污垢的热阻125370087（污垢系数），天津大学出版社2005年版，第354页。传热面积裕度传热面积该换热器的实际传热面积a 则该换热器的面积裕度按式/在1.151.25范围内，传热面积裕度合适，该换热器能完成生产任务。故该换热器合适。3、壁温核算因管壁很薄，且管壁热阻很小，故壁温可按式 计算。由于传热管内侧污垢热阻较大，会使传热管壁温升高，降低了壳体和传热管壁温之差。但在操作初期，污垢热阻较小，壳体和传热管间壁温差可能较小。计算中应按最不利的操作条件考虑，因此取两侧污垢热阻为零计热。于是上式变为 气体平均温度液体平均温度（端流）带入计算得 与凯恩式中假设相差不大，故假设合适。设计数据结果一览表参数管程壳程流量（kg/h）90000进/出口温度（）20/94133.3/133.3压力（kpa）常压300（绝压）物性参数定性温度（）57密度（kg/m3）834.53935.3302定压比热容（j/(kg)）1686.13541973.5粘