列管式换热器的工艺设计和选用

1、.wd化工原理课程设计说明书题 目： 列管式换热器的工艺设计和选用 课程名称： 化工原理课程设计 设 计 人： 吴琳瑜 专 业： 化学工程与工艺 班 级： 化工B081 学 号： 20xx01034119 指导教师： 李辰明 日期： 20xx.12.19学校：华北科技学院目录设计条件··························&#

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11、183;·····················31.选择换热器类型··························

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15、83;······················4三、估算传热面积··························

16、···············································41.计算热负荷·

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20、183;··43.传热平均传温差·············································

21、3;·························4四、初算传热面积·······················&

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23、五、工艺构造尺寸················································

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26、183;··52.总管数和管程数·············································

27、3;························53.初选换热器类型与型号·······················

28、83;·····································54.确定管子在管板上的排列方式··········

29、;········································55管子与管板、管板与壳体的连接·······&

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32、183;··········67.确定实际管子数目·····································

33、83;····························68.折流挡板····················&#

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35、183;·······69.其他附件·········································&

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38、#183;····················7六、换热器核算····························

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41、83;·········8 管内传热膜系数·······································

42、···························8 管外传热膜系数·····················

43、83;···········································8 污垢热阻和管壁热阻····

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45、3;·····9 总传热系数K···········································&#

46、183;··························9传热面积校核······················&

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52、······················10 壳程压力降··························

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56、83;············································12参考文献····

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58、83;······························13CAD图纸··················&#

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60、183;···············14设计题目：列管式换热器的工艺设计和选用设计条件炼油厂用原油将柴油从175冷却到130。柴油流量为12500 kg/h原油初温为70，经换热后升温到110。换热器的热损失可忽。管、壳程阻力压降不大于30kpa。污垢热阻均取0.0003 m2··W-1 。试设计一台列管式换热器，完成该生产任务。设计任务（1） 根据设计条件选择适宜的换热器型号，并核算换热面积，压力降是否满要求，并设计管道与

61、壳体的连接，管板与壳体的连接，折流板数目、形式等。（2） 绘制列管式换热器的装配图。（3） 编写课程设计说明书。设计原那么1.满足工艺和操作要求设计出来的流程和设备首先要保证质量，操作稳定，这就必须配置必要的阀门和计量仪表等，并自确定方案时，考虑到各种流体的流程，温度和压强变化使采取什么措施来调节，而在设备发生故障时，加修应方便。2.满足经济上的要求在确定某些操作指标和治标和选定设备型式以及仪表配置时，要有经济核算的观点，既能满足工艺和操作要求，又使施工简便，材料来源容易，造价低廉。如果有废热可以利用，要尽量节省热能，充分利用，或者采取适当的措施到达降低本钱的目的。3.保证安全生产 在工艺流程

62、和操作中假设有爆炸、燃烧、中毒、烫伤等危险，就要考虑必要的安全措施。又如设备的材料强度的演算，除按规定应有一定的安全系数外，还应考虑防止由于设备中压力突然升高或者造成真空而需要装置安全阀等，以上提到的都是为了保证安全生产所需要的。设计方案也可能一次定不好，后来需要修改，但各物料流通路线和操作指标的改动都对后面的计算的影响，所以最好第一次确立就考虑周到些。设计流程一、确定设计方案1.选择换热器类型两流体的温度变化情况：热流体进口温度为175，出口温度为130。冷流体进口温度为70，出口温度为110由于冷、热流体温差较大，同时为了便于拆卸清洗，选用浮头式列管换热器。2.确定冷、热流体流径途径由于柴

63、油较易结垢，为便于清洗，应使柴油走管程，原油的粘度大，在装有折流挡板的壳程中流动。有利于提高湍动，增大传热系数，原油走壳程。二、流体有关物性数据物料 kg/m3kJ/(kg)W·m-1·-1Pa·s原油815 0.128柴油 715 0.133三、估算传热面积1. 计算热负荷忽略热损失 W2. 冷却水用量(忽略热损失) kg/s3. 传热平均传温差先按逆流计算= 温度校正：R0.38P1.13据R、P值，查温差校正系数图，得温度校正系数=×=0.92×62.5=57.50四、初算传热面积参照传热系数K的大致范围，取=230 W/ (m2

64、3;),那么估算面积为：=取实际面积为估算面积的1.1倍，那么实际估算面积为： A=1.1=1.1×29.30=32.23 m2五、工艺构造尺寸1.选管子规格选用252.5mm的无缝钢管，管长L=6m。2.总管数和管程数总管数 根单程流速 =单程流速较低，为提高传热效果考虑采用多管程。按管程流速的推荐范围，选管程流速为=1m/s，所以管程数为= 取4管程3. 初选换热器类型与型号由于冷、热流体温差较大，同时为了便于拆卸清洗，选用浮头式列管换热器为宜，且初步选定的具体型号为 BES400-1.0-31.6-6/25-4IIBES400-1.0-31.6-6/25-4II的具体参数壳径/

65、mm400管子尺寸25mm×2.5mm公称压力/MPa1.00管长/m6计算换热面积/m31.6管子总数68管程数4管子排列方式四边形错列壳程数1折流挡板形式弓形4. 确定管子在管板上的排列方式管子布置应在换热器的截面上均匀而紧凑的分布，此外还有考虑流体的性质和构造设计及制造等方面的问题 管子的排列方式有等边三角形和正方形两种。如图a、图b所示。与正方形相比，等边三角形排列比较紧凑，管外流体湍动称帝高、外表传热系数大。正方形排列虽比较松散，传热效果也较差，但管外清洗方便，对易结垢流体更为适用。如将正方形排列的管束转45度安装如图c可在一定的程度上提高对流传热系数，采用正方形错列。5管

66、子与管板、管板与壳体的连接 在管壳式换热器的构造设计中，管子与管板的连接是否严密十分中。如果连接不严密，在操作时连接处发生泄漏，冷热流体互相混合，会造成物料和热量损失；假设物料带有腐蚀性、放射性或者两种流体接触会产生易燃易爆物质，后果将更加严重。在固定管板式换热器的连接方法处还应考虑能承受一定的轴向力，以防止温度变化较大时，产生的热应力使管子从管板脱出。焊接法由于具有很多的优点加工简单、对管空的加工要求不高，较强的抗脱能力使之在高温高压下仍能保持连接处的严密性，同时在压力不太高时还可采用薄型管板，在一些要求较高的场合被广泛应用。管子与管板采用焊接构造。 浮头式换热器通常是把管板夹在壳体法兰与管

67、箱法兰之间便于管壳程一起清洗。管心距取 a=1.25d0 =1.25×25=31.2532mm 隔板两侧相邻管心距 6. 壳体内径确实定 取管板利用率=0.8，那么壳体内径为：按壳体标准圆整取 7.确定实际管子数目N=688.折流挡板换热器内安装折流挡板是为了提高壳程流体的对流传热系数。为了获得良好效果，折流挡板的尺寸和间距必须适当。对于常用的圆缺形挡板，弓形切口太大或太小，都会产生流动“死区，如以下列图，不利于传热，且增加流体阻力。一般切口高度与直径之比为0.15-0.45，常见的有0.20和0.25两种。 挡板的间距对壳程的流动有重要的影响，间距太大不能保证流体垂直流过管束，使得管外给热系数降低，间距太小又不方便检修，阻力损失也很大。一般采用间距为壳体的0.2-1.0倍。取板间距B200mm。 而对圆缺形挡板而