化工原理课程设计实例.doc

列管式换热器设计说明书

设计者：班级：环境工程092
姓名：###
学号：##
日期：2011年6月24日

指导教师

目录

一、方案简介································································3

方案设计································································4

确定设计方案·····························································4

确定物性数据·····························································4

计算总传热系数···························································4

计算传热面积·····························································5

工艺结构尺寸·····························································5

换热器核算·······························································7

设计结果一览表··························································10

对设计的评述····························································11

附图（主体设备设计条件图）（详情参见图纸）·································

参考文献································································12

主要符号说明····························································12

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。

设计任务要求：将硝基苯液体从130℃冷却到35℃。处理能力为16×105吨/年。冷却介质采用水，入口温度28℃。要求换热器的管程和壳程的压降不大于100kPa。试设计能完成上述任务的列管式换热器。（每年按365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（硝基苯）进口温度135℃，出口温度35℃冷流体。
冷流体（冷却水）进口温度28℃，假设值出口温度38℃。
从两流体温差为T-t=49.5℃（<50℃），因此初步确定选用固定管板式换热器。
（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。同时，在此选择逆流。选用ф25×2.5的碳钢管，管内流速假设选取ui=0.79m/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。
冷却水在20℃与40℃时ρ定压比热容cp、导热系数λ、黏度μ分别为：
20℃：998.2kg/m34174kJ/(kg·℃)61.8W/(m·℃)0.001004Pa·s
40℃：992.2kg/m34.174kJ/(kg·℃)0.635W/(m·℃)0.000653Pa·s
冷却水在33℃下的物性数据：
密度ρo=ρ20℃-(33-20)（ρ20℃-ρ40℃）/（40-20）=94.65kg/m3
定压比热容cpo=cp20℃-(33-