列管式换热器的设计

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1、目录一、方案简介································································1二、方案设计································································21、确定设计方案·····························································22、确定物性数据·······························

2、······························23、计算总传热系数···························································34、计算传热面积·····························································35、工艺结构尺寸·····························································46、换热器核算······

3、·························································5三、设计结果一览表··························································8四、附图（主体设备设计条件图）（详情参见图纸）································8五、参考文献································································9

4、三、主要符号说明····························································9四、心得体会·································································10附图··········································································一、方案简介本设计任务是利用冷流体（水）给硝基苯降温。利用热传递过程中

5、对流传热原则，制成换热器，以供生产需要。下图（图1）是工业生产中用到的列管式换热器.选择换热器时,要遵循经济,传热效果优,方便清洗,复合实际需要等原则。换热器分为几大类：夹套式换热器，沉浸式蛇管换热器，喷淋式换热器，套管式换热器，螺旋板式换热器，板翅式换热器，热管式换热器，列管式换热器等。不同的换热器适用于不同的场合。而列管式换热器在生产中被广泛利用。它的结构简单、坚固、制造较容易、处理能力大、适应性大、操作弹性较大。尤其在高压、高温和大型装置中使用更为普遍。所以首选列管式换热器作为设计基础。9二、方

6、案设计某厂在生产过程中，需将硝基苯液体从100℃冷却到45℃。处理能力为1.5×105吨/年。冷却介质采用自来水，入口温度30℃，出口温度40℃。要求换热器的管程和壳程的压降不大于10kPa。试设计能完成上述任务的列管式换热器。（每年按330天，每天24小时连续运行）1．确定设计方案（1）选择换热器的类型两流体温度变化情况：热流体进口温度100℃，出口温度45℃冷流体。冷流体进口温度30℃，出口温度40℃。从两流体温度来看，估计换热器的管壁温度和壳体壁温之差不会很大，因此初步确定选用固定管板式换热器。

7、（2）流动空间及流速的确定由于硝基苯的粘度比水的大，因此冷却水走管程，硝基苯走壳程。另外，这样的选择可以使硝基苯通过壳体壁面向空气中散热，提高冷却效果。同时，在此选择逆流。选用ф25×2.5的碳钢管，管内流速取ui=0.5m/ｓ。2、确定物性数据定性温度：可取流体进口温度的平均值。壳程硝基苯的定性温度为：管程流体的定性温度为：根据定性温度，分别查取壳程和管程流体的有关物性数据。硝基苯在72.5℃下的有关物性数据如下：密度　　ρo=1153kg/m3定压比热容　cpo=1.559kJ/(kg·℃)导热系

8、数　　λo＝0.129W/(m·℃)粘度　　μo=0.000979Pa·s冷却水在35℃下的物性数据：密度　　ρi=994.3kg/m3定压比热容　cpi=4.24kJ/(kg·℃)导热系数　　λi=0.618W/(m·℃)粘度　　　　μi=0.000818Pa·s3．计算总传热系数（1）热流量热流体的流量Wo=1.5×105×1000÷330÷24≈18939kg/h热流量Qo=WocpoΔto=18939×1.559×(100-45)=1623925