化工原理课程设计

一、设计方案简介 ················································································································2 ㈠、设计意义 ·····················································································································2 ㈡、选用浮头式换热器 ······································································································2 二 设计计算 ·························································································································3 ㈠、选定设计方案 ··············································································································3

①选择换热器的类型 ··································································································3 ②流动空间及流速的确定 ···························································································3 ㈡、确定物性数据 ··············································································································3

①定性温度：可取流体进口温度的平均值。 ····························································3 ②根据定性温度，分别查取壳程和管程流体的有关物性数据。 ······························3 ㈢、设传热系数K ··············································································································4

①热流量 ·····················································································································4 ②平均传热温差 ··········································································································4 ③冷却水用量 ··············································································································4 ④平均传热温差 ··········································································································4 ㈣、计算传热面积 ··············································································································5 ㈤、工艺结构尺寸 ··············································································································5

①管径和管内流速 ······································································································5 ②管程数和传热管数 ··································································································5 ③传热管排列和分程方法 ···························································································5 ④壳体内径 ··················································································································6 ⑤折流板 ·····················································································································6 ⑥接管 ·························································································································6 ㈥、换热器核算 ··················································································································6

①热量核算 ··················································································································6 ②管程对流传热系数 ··································································································7 ③传热系数 ··················································································································8 ④传热面积 S ··············································································································8 ㈦、换热器内流体的流动阻力 ···························································································8

①管程流动阻力 ··········································································································8 ②壳程阻力 ··················································································································9 ㈧、换热器主要结构尺寸和计算结果 换热器主要结构尺寸和计算结果见下表 ···········9

换热器装配图 ············································································· 错误！未定义书签。

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一、设计方案简介

㈠、设计意义

在食品工业中的加热、冷却、蒸发和干燥的单元操作中，经常见到食品物料与加热或冷却介质间的热交换，而用于进行热交换的设备称为换热器。换热器还广泛应用于化工、石油化工、动力、医药、冶金、制冷、轻工等行业。在众多类型的换热器结构中，管壳式换热器应用最为广泛，因此要根据特定的工艺要求，设计合理的换热器，以满足不同场所的需求。 ㈡、选用浮头式换热器

浮头式换热器浮头端结构，它包括圆筒、外头盖侧法兰、浮头管板、钩圈、浮头盖、外头盖及丝孔、钢圈等组成，其特征是：在外头盖侧法兰内侧面设凹型或梯型密封面，并在靠近密封面外侧钻孔并套丝或焊设多个螺杆均布，浮头处取消钩圈及相关零部件，浮头管板密封槽为原凹型槽并另在同一端面开一个以该管板中心为圆心，半径稍大于管束外径的梯型凹槽，且管板分程凹槽只与梯型凹槽相连通，而不与凹型槽相连通。

图1-1浮头式换热器的示意图

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二 设计计算

㈠、选定设计方案

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120℃，出口温度40℃；冷流体（循环水）进口温度25℃，出口温度55℃。该换热器用循环冷却水冷却，采用浮头式换热器。 ②流动空间及流速的确定

由于循环冷却水较易结垢，为了便于水垢清洗，应使用循环冷却水走管程，油品走壳程。选用Φ25×2.5的碳钢管，管内流速取u=0.5m/s

㈡、确定物性数据

①定性温度：可取流体进口温度的平均值。 壳程油的定性温度为

T12040802(℃)

管程流体的定性稳定为

t2555402(℃)

②根据定性温度，分别查取壳程和管程流体的有关物性数据。 油在90℃下的有关物性数据如下：

3781kg/m0密度

定压比热容 导热系数 粘度

cpo2.28kJ/(kg℃)

00.144W/(m℃) 00.0006Pas

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循环冷却水在35℃下的物性数据：

3992.2kg/mi密度

定压比热容 导热系数

cpi4.174kJ/(m℃)

i0.6338W/(m℃)

粘度

㈢、设传热系数K

i0.000656Pas

①热流量

Qomocpoto150002.22(12040)2.736106kJ/h760.069KW

②平均传热温差

'tmt1t2(12055)(4025)34.099℃t112055lnlnt24025

③冷却水用量

Q02.736106kJ/hi21850kg/hcpiti4.174kg/(kg℃)30④平均传热温差

2u0.5m/sK250W/(m℃) i选用Φ25×2.5传热管（碳钢）， 取管内流速

平均传热温差校正系数

55250.3161202512040R2.66730 P

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按双壳程，四管程结构，查表得温差校正系数

t0.94

'tt0.9434.09932.05℃ mtm平均传热温差：

㈣、计算传热面积

S'Q76009694.86(m2)Ktm25032.05

按照国家换热器标准选择

选用二壳程四管程 L6m,s118.194.86 满足要求

所以n=256根，D=700mm，中心管数为12，管程传热面积为0.0201m

㈤、工艺结构尺寸

2①管径和管内流速

选用252.5的传热管（碳钢），取管内流速 ui0.5m/s

②管程数和传热管数

采用4管程，传热管数为256根。 ③传热管排列和分程方法

采用组合排列法，即每程内均按正三角形排列，隔板两侧采用正方形排列。取管心距

t1.25do，则

t1.252531.2532(mm)

横过管束中心线的管数

nc1.19N1.1724018.44(根)

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④壳体内径

采用多管程结构，取管板利用率0.7，则壳体内径为

D1.05tN/圆整可取 D1.0532圆整可取 D=450mm ⑤折流板

240622.15(mm)0.7

采用弓形折流板，取弓形折流圆缺高度为壳体内径的25%，则切去的圆缺高度为

0.25×700=175（mm), 故可取 h=170(mm)

取折流板间距B=0.25D，则B=0.25×700=175(mm) ，可取B为 180mm 。

折流板数

NB传热管长6000-1132.3(块)折流板间距180 取33块

折流板圆缺面水平装配。 ⑥接管

壳程流体进出口接管：取接管内油品流速为u1.0m/s，则接管内径为

d4V415000/(3600825)0.051(mm)u3.141.0

取标准管径为50mm

管程流体进出口接管：取接管内循环水流速u1.5m/s，则接管内径为

d415125/(3600992)0.0600(m)3.141.5

取标准管径为60mm

㈥、换热器核算

①热量核算

壳程对流传热系数 对圆缺形折流板，可采用克恩公式

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00.36

0de.55Re0Pr3(0100.14)w

量直径，由正三角形排列得

4(de322td0)4(3/20.03220.7850.0252)240.020(m)d03.140.025

d00.025)0.1800.65(1)0.025594(m)t0.032

壳程流通截面积

S0BD(1壳程流体流速及其雷诺数分别为

u015000/(3600781)0.20845(m)s0.025594

0.0200.20845781Re04903.60.0006

普兰特准数

2.281036106Pr10.510.144

0.14)0.95黏度校正 0

(00.3610.1414903.60.5510.5130.95416.1W2(m℃) 0.027②管程对流传热系数

i0.023

idiRe0.8Pr0.4

管程流通截面积

Si0.7850.022管程流体流速

2560.0401922

ui21850/(3600992.2)0.1623(m)s0.3768

0.02992.20.1623Re491130.65610

普兰特准数

4.1741036.56104Pr4.320.6338

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i0.023③传热系数

0.633849110.84.320.41174W/(m2℃)0.02

K1d0dbd1Rsi00Rsoidididi010.0250.0250.00250.02510.0003440.0017211740.020.02450.0225416.12242.03W/(m℃) ④传热面积 S

SQ76006997.98m2Ktm242.0332.05

该换热器的实际传热面积

Sp

Spd0L(Nnc)3.140.0256(25612)114.92m2该换热器的面积裕度为

HSpSS100%114.9297.98100%17.3%97.98

传热面积裕度合适，该换热器能够完成生产任务。

㈦、换热器内流体的流动阻力

①管程流动阻力

Pi(P1P2)FtNsNpNs2,Np4,Ft1.5

lu2u2P,P21id22

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0.010.0050.045W/m℃，流速20由Re=4911，传热管相对粗糙度查莫狄图得iui0.1623m/s,992.2kg/m3，所以60.16232992.2P176.42(Pa)10.0450.022u2992.20.16232P2339.2(Pa)22Pi(176.4239.2)1.527(Pa)15KPa

管程流动阻力在允许范围之内。 ②壳程阻力

''Po(P1p2)fnNsNS1,Ft1流体流经管束的阻力

'P1Ffonc(NB1)

2uo2F0.5f0563040.2280.6802nc20NB33,u00.26807810.26802P0.50.680220(331)86(Pa)2

'1流体流过折流板缺口的阻力

22Bu0PNB(3.5)D2B0.18m,D0.7m'220.187810.26802P33(3.5)2763(Pa)0.72

'2总阻力

PPa15KPa 08627639249课程流动阻力也比比较适宜。

㈧、换热器主要结构尺寸和计算结果 换热器主要结构尺寸和计算结果见下表

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换热器型式：固定管板式 换热面积（㎡）：97.98 工艺参数 名称 物料名称 操作压力，MPa 操作温度，℃ 流量，kg/h 流体密度，kg/m³ 流速，m/s 传热量，kW 总传热系数，W/㎡.K 对流传热系数，W/㎡.K 污垢系数，㎡.K/W 阻力降，MPa 程数 推荐使用材料 管子规格 φ25×2.5 管间距，mm 折流版型式 壳体内径，mm

32 上下 700 排列方式 间距mm 180 管程 循环水 0.4 25/55 21850 992 0.1623 760 242.0 1174 0.000344 0.0007 4 碳钢 管数 256 416 0.000172 0.009249 2 碳钢 管长mm 正三角形 切口高度 25% 6000 壳程 壳程 0.3 120/40 15000 781 0.2680 保温层厚度，mm 10

管口表 a b c d e f

DN DN 循环水入口 循环水出口 油品入口 油品出口 排气口 放净口 平面 平面 凹凸面 凹凸面 凹凸面 凹凸面 DN DN DN DN 11