化工原理设计原油换热器

1、化工原理课程设计题目: 原油加热器固定式换热器指导教师 :李先生院士职称:国家特级院士班级:高分子材料与工程系学号:学生姓名 :目录一绪论 ······································&#

2、183;·············································· 3二、设计条件及主要物性数 ·

3、;··················································

4、;·······4参1、设计条件 ·········································&#

5、183;·································42、定性温度的确定 ··············

6、83;·················································

7、83;·4三.确定设计案 ···············································

8、···························5方1、选择换热器的型·····················&

9、#183;··········································5类2、流程安排 ·····

10、3;·················································

11、3;···················5四估算传热积 ·····························&#

12、183;·······································5面量1、热·········&#

13、183;························流·························&

14、#183;·················· 52、平均传热温差·····························

15、83;·······································53、传热面积·········&#

16、183;·················································&#

17、183;··············· 5五工程结构尺寸·································

18、;········································61、管径和管内流速········&

19、#183;·················································6

20、2、管程数和传热管数················································&#

21、183;·········63、平均传热温差校正及壳数······································

22、················64、传热管的排列和分程方法· ······························

23、83;···············75、折流板·································

24、83;·············76、接管···································

25、3;···········7六、换热器核算·····································&#

26、183;·········81、壳程传热系数·······································

27、;········82、管程传热系数········································&#

28、183;······83、污垢热阻和管壁热阻·········································&#

29、183;·····94、总传热系数K···········································

30、;····105、传热面积裕度············································&

31、#183;·107、管程流动阻力··············································

32、83;118、壳程流动阻力···············································11七、设

33、计计算结果汇总···············································12一、绪论1. 加热

34、器简介1.1. 固定管板式固定管板式换热器的两端管板和壳体制成一体，当两流体的温度差较大时，在外壳的适当位置上焊上一个补偿圈（或膨胀节）。当壳体和管束热膨胀不同时，补偿圈发生缓慢的弹性变形来补偿因温差应力引起的热膨胀。特点：结构简单，造价低廉，壳程清洗和检修困难，壳程必须是洁净不易结垢的物料。形管式U 形管式换热器每根管子均弯成U 形，流体进、出口分别安装在同一端的两侧，封头内用隔板分成两室，每根管子可自由伸缩，来解决热补偿问题。特点：结构简单，质量轻，适用于高温和高压的场合。管程清洗困难，管程流体必须是洁净和不易结垢的物料。1.3. 浮头式换热器两端的管板，一端不与壳体相连，该端称浮头。管子

35、受热时，管束连同浮头可以沿轴向自由伸缩，完全消除了温差应力。 特点：结构复杂、造价高，便于清洗和检修，完全消除温差应力，应用普遍。本实验采用的是浮头式加热器，包括输油管，输油管上套有密闭的外壳，外壳的一段管道上设有加热体，该加热体用固定卡固定在外壳表面上，所述外壳的外表面上包覆有保温层。本实用新型具有传热速度快、均温性好的特点，避免了在输送过程中热损失大而导致油品凝固难以输送的问题。2. 设计目的培养学生综合运用本门课程及有关选修课程基础理论和基础知识完成某项单元操作设备设计的实践操作能力。 设计的设备必学在技术上是可行的， 经济上是合理的，操作上是安全的，环境上是友好的。二、设计条件及主要物

36、性参数2.1 设计条件由设计任务书可得设计条件如下表：参数体积流量进口温度出口温度设计压力类型（标准 t/h ）（）（）（Kpa）柴 油34175-80原油337011080项目密度 比热 Cp导热系数黏度 3）（kJ/kg?C ）2（Pa?s）（ kg/m（W/m?）柴油7152.480.1330.6410 3原油8152.20.1286.6510 32.2. 定性温度的确定Wc: 原油流量（ kg/h ）Wh:柴油流量（ kg/h ） C pc: 原油比热容Cph： 柴油比热容t1，t 2：原油的出、进口温度T1、T2: 柴油的进、出口温度根据夏清陈常贵化工原理（上） P225，公式（ 4

37、-33 ），热流量为Qc = Wc Cpc(t 1 t 2) =33 000×2.2 ×（ 11070） /3.6=806667 W柴油出口温度： Qh = Qc = Wh Cph (T 1 T2)806667=34000×2.48 ×（ 175 T2 ）/3.6T2 =140.5可取流体进出口温度的平均值。管程柴油的定性温度T= （175+140.5）/ 2=157.5 壳程原油的定性温度为t=(70+110) / 2=90三、确定设计方案3.1选择换热器的类型由设计任务选择固定管板式换热器。3.2流程安排柴油温度高，走管程可减少热损失，原油黏度较大，

38、走壳程在较低的 Re数时即可达到湍流，有利于提高其传热膜系数。四、估算传热面积4.1 热流量4.2 平均传热温差根据化工原理课程设计P47，公式（ 3-9 ）t m = (T1t2 ) (T2t1 ) = (175 110)(140.5 70) =67.8 224.3 传热面积-2-1根据夏清陈常贵化工原理（上） P356表，初步设定 K=160W·m · 。根据化工原理课程设计P47，公式（ 3-5 ）五工程结构尺寸5.1 管径和管内流速选用 25×2.5mm的传热管 ( 碳钢管 ) 。5.2 管程数和传热管数根据估算的传热面积，然后查JB1145-73 得：公

39、称直径 D管管管管程流通面积（ mm）程数长( m 2 )数（mm）500216860000.0264传热面积A=77.9m2外径D=500mm管程N=2单程传热管数n=168管程流通面积Si =0.0264 m2该换热器型号为G500 -2.5-805.3平均传热温差校正及壳程数根据化工原理课程设计P47，公式（ 3-12 ）平均传热温差校正系数RT1T2175140.50.86t2t111070P t2t1110700.381T1t117570根据夏清陈常贵化工原理（上） P231，公式（ 4-46 ）平均传热差校正为tm=67.8 × 0.95=64.4 ( )t ×

40、tm由于平均传热温差校正系数大于0.8 ，同时壳程流体流量较大，故取单壳程合适。5.4传热管的排列和分程方法采用正三角形排列法，则管间距t=32mm5.5 折流板采用弓形折流板 ,取折流板间距 B=400 mm。传热管长1= 6000 1=14 块折流板数 NB=折流板间距400折流板圆缺面水平装配。5.6 接管（1）壳程流体进出口接管取接管内液体流速u1=1.0m/s,D14v433000/(3600815) =119.2mmu13.14 1圆整后取管内直径为120mm.(2) 管程流体进出口接管取接管内液体流速 u 2 =1.5m/s,圆整后取管内直径为130mm六换热器核算6.1 总传热

41、系数核算6.1.1 壳程传热系数根据夏清 陈常贵 化工原理（上） P253，公式 94-77a)得Re0.55Pr 1 / 30= 0.36 o( o )0.14d ew其中：o0.14粘度校正为 ()=0.92w当量直径，管子为正方形旋转45 0 形排列时，根据化工原理（上）P253，公式（4-78 ）得4(t 2d 2o )432 10323.14240.025d 4=0.027ed o3.140.025壳程流通截面积，根据化工原理（上）P253，公式（ 4-80 ），得Ao = BD(1 do )=0.400 ×0. 500×（ 1 0.025） 0.044m2t0.

42、032式中B两挡板间距离， mD 换热器间的外壳内径， m壳程原油的流速及其雷诺数分别为u Vo=33000 /(3600 815)0.26 m/soAo0.044Reoo uod e815 0.26 0.027860o6.65 10 3普朗特准数（ <传热传质过程设备设计 >P26，公式 1-43 ）Pr c po o = 2.21036.65 10 3=114.3o0.128因此，壳程水的传热膜系数0 为Re 0.55Pr1/ 30= 0.36 o( o )0.14dew0.1288600.5510.922=114.330.36·)=308W/(m0.027管程传热系

43、数根据夏清陈常贵化工原理（上） P248 ，公式（ 4-70a ）得i = 0.023Re0.8Pr0.4i其中：di管程流通截面积Si=0.0264m2管程柴油的流速及其雷诺数分别为ui Vi= 34000 /(3600 715) 0.5 m/sSi0.0264i uidi0.02 0.5 71511172Re0.64 10 3i普兰特准数c pii=2.48 1030.64 103Pr 0.133=11.93i因此，管程空气的传热膜系数i 为0.8×11.930.4×0.1332i 0.023 ×111720.02=714W/(m·)污垢热阻和管壁热阻查阅夏清陈常贵化工原理（上） P354，附录表 20，得原油侧的热阻2-1so0.00034m··WR柴油侧的热阻2-1si 0.00034m··WR查阅化工原理（上） P354，附录表 13，得-1-1碳钢的导热系数 50W·m·总传热系数 K因此，查夏清陈常贵 化工原理（上）P227，公式（ 4-4