二甲苯三甲苯

--10-化工原理课程设计Ⅰ.原始数据1. 设计题目：双组分连续精馏筛板塔的设计2. 原料处理量：1.46×104kg/h原料组成：组分名称组分名称0.56三甲苯10.975〔质量分率。〔20.974〔质量分率。1：操作压力：常压。〔2：进料及回流状态：泡点液体。Ⅱ.设计计算一、 物料衡算：0.560.561061060.560.5610610610.56120原料液摩尔分率：x F

0.590.97500.9750.975106106120D

0.9779M=0.59×106＋(1－0.59)×120＝111.74kg/kmolF146104=131kmol/h111.74塔顶易挥发组分回收率：

DxDFxF

0.974

D0.97791310.59

0.974∴D76.982kmol/h总物料衡算：FDW ∴WFD＝131－76.982＝54.018kmol/hFx DxF

WxW

131×0.59＝76.982×0.9779＋54.018×xW∴x =0.0372W二、 塔顶温度、塔底温度及最小回流比的计算：确定操作压力：塔顶压力：760mmHg塔底压力：760mmHg +25×100mmH计算塔顶温度〔露点温度〕

O=943.8235mmHg2依据塔顶压力及塔顶汽相组成用试差法计算塔顶温度。其中二甲苯、三甲苯的饱和蒸气压由安托因方程计算。=设t 141.28℃=顶由lgP0A

.000

1463t 214.7顶

P=776.6378mmHgA由lgP0

.074

1608

P=345.9854mmHgB t 213.3 B顶P0k AA P

776.6378760

1.0219

P0k BB P

345.9854 0.4552760yx AA kA

.97791.0219

0.9569

yx B kB

10.9770.4552

0.0486x 10.95690.048610.005=0.0004i=t 141.28℃假设不正确=顶=设t 141.48℃=顶由lgP0

1463

P=780.7756mmHgA t 214.7 A顶由lgP0B

.074

1608t 213.3顶

P=348.0276mmHgBP0k A

780.7756

B1.0273 B

P0

348.02760.4579A P 760y 0.9779

B P 760y 10.977x AA kA

0.9519 x BB kB

0.4579

0.0483x 10.95190.048310.0002 =0.0004i=t 141.48℃假设正确，为所求露点温度。=顶A∴ P A

780.7756

2.2434顶 P0B

348.0276计算塔底温度〔泡点温度〕苯的饱和蒸气压由安托因方程计算。t=179.04℃由lgP0A

.000

1463t 214.7底

P=1924.6524mmHgA由lgP0B

.074

1608t 213.3底

P=945.1788mmHgBP0k A

1924.6425

2.0392

PB

945.1788

1.00140A P 943.8235 B P 943.82350y x kA A

0.03722.0392 0.0759 yB

x kB

10.03721.0014 0.9641y 10.07590.964110.04=0.0004i℃t =179.04 假设不正确。℃底℃设t =177.41℃底由lgP0A由lgP0B

.0007.074

1463t 214.7底1608t 213.3底

P=1857.3944mmHgAP=908.6896mmHgBP0k A

1857.3944

1.9679

PB

908.6896

0.96280A P 943.8235 B P 943.82350y x kA y x kB B

0.03721.9679 0.07320.9270 yi

10.07320.927010.0002 =0.0004底t =177.41℃假设正确，为所求泡点温度。底A∴ P A顶 P0B

1857.3944908.6896

2.0440 顶 底2 顶 底2.24342.0440

2.14Rmin：q1 x xe F

0.59 ye

x 1 1xe

0.7549x yR D

0.97790.7549

1.35min

y xe

0.75490.59三、 确定最正确操作回流比与塔板层数：列相平衡关系式：xn列操作线方程：

y1yn 1yn

y n2.141.14yny

n1

R x R1 n

xDR1y

LF xLFW

W xLFW 由塔顶向下逐板计算精馏段的汽、液相组成，即

，由操作关系计算y

，由平衡关系计算Dx2,…由平衡关系计算x

1nnnn

2F时，则n-1即为精馏段的理论板数。F由进料口向下逐板计算提馏段的汽、液相组成，即xxmy2x2，由操作关系计算xxmmm逐板法计算塔板层数：

≤时，则 即为提馏段的理论板数。m w0.1Rmin，逐次增大操作回流比，2-41) R=1.1Rmin 精馏段：y =0.598x +0.3935n1 n提馏段：y =1.2824x -0.0105m1 m精馏段 提馏段nxymxy10.95390.977910.57920.746620.92580.963920.56100.732330.89330.947130.53240.708940.85710.927740.48940.672250.81840.906050.42950.617160.77890.882960.35450.540370.74050.859370.27190.444180.70480.836380.19270.338290.67300.815090.12660.2366100.64570.7960100.07720.1519110.62310.7796110.04340.0885120.60480.7661120.21060.0452130.59040.7552140.57920.7466N =25〔包括釜〕NT

=13 N精 提

包括釜〕2) R=1.2Rmin yn1=0.618xn+0.3732ym1=1.2678xm-0.0100精馏段 提馏段nxymxy10.95390.977910.57740.745220.92340.962720.54830.722030.88710.943930.50410.685140.84570.921440.44220.629150.80070.895850.36410.550660.75460.868060.27790.451670.70970.839570.19560.342380.66840.811880.12740.238090.63220.786390.07700.1515100.60190.7639100.04290.0876110.57740.7452110.02130.0444N =21〔包括釜〕NT

=10 N提

3) R=1.3Rmin 精馏段：y =0.637x +0.3550n1 n提馏段：y =1.2547x -0.0095m1 m精馏段提馏段nxymxy10.95390.977910.57090.740120.92330.962620.52970.706830.88570.943130.47030.655140.84170.919240.39280.580650.79280.891250.30420.483360.74170.860060.21690.372270.69140.827570.14270.262680.64500.795480.08710.169590.60450.765990.04920.0998100.57090.7401100.02510.0522N =19〔包括釜〕NT

=9 N提

包括釜〕4) R=1.4Rmin 精馏段：y =0.654x +0.3384n1 n提馏段：y =1.2428x -0.0090m1 m精馏段提馏段nxymxy10.95390.977910.57530.743620.92250.962320.82880.705930.88310.941730.46261.021040.83590.915940.37860.565950.78210.885150.28590.461560.72620.849960.19850.346370.67060.813370.12720.237780.61950.777080.07570.149190.57530.743690.04160.0851100.02040.0427N =18〔包括釜〕NT

=8 N提

包括釜〕5) R=1.5Rmin yn1=0.669xn+0.3233n精馏段x ym提馏段x y10.9539 0.977910.5441 0.718620.9210 0.961520.4775 0.6617n精馏段x ym提馏段x y10.9539 0.977910.5441 0.718620.9210 0.961520.4775 0.661730.87880.939430.39190.579740.82740.911240.29650.474250.76890.876850.20580.356760.70690.837760.13160.244970.64610.796270.07820.153580.59090.755580.04300.087790.54410.718690.02120.0444N =17〔包括釜〕NT

=8 N提

包括釜〕6) R=1.6Rmin 精馏段：y =0.684x +0.3095n1 n提馏段：y =1.2221x -0.0083m1 m精馏段提馏段nxymxy10.95390.977910.57720.744920.92200.962020.51810.697130.88010.940130.43770.624940.82790.911540.3420.526650.76720.875850.24490.409760.70170.834360.16090.291070.63660.789570.09780.188380.57720.744980.05530.111290.02860.0593N =16〔包括釜〕NT

=7 N提

包括釜〕7) R=1.7Rmin 精馏段：y =0.697x +0.2968n1 n提馏段：y =1.2130x -0.0079m1 m精馏段提馏段nxymxy10.95390.977910.55610.728320.92140.961720.48310.666630.87800.939030.39030.578140.82310.908840.28930.465550.75860.870550.19610.343060.68860.825560.12250.230070.61910.776870.07110.140780.55610.728380.03820.078390.01830.0384N =16〔包括釜〕NT

=7 N提

包括釜〕8) R=1.8Rmin yn1=0.708xn+0.2851ym1=1.2046xm-0.0076精馏段 提馏段nxymxy10.95390.977910.52700.704520.91900.960520.44020.627230.87190.935830.33850.522740.81210.902440.23760.400250.74170.860150.15290.278660.66620.810260.09110.176670.59240.756870.05050.102180.52700.704580.02570.0532N =15〔包括釜〕NT

=7 N提

包括釜〕9) R=1.9Rmin 精馏段：y =0.719x +0.2743n1 n提馏段：y =1.1968x -0.0073m1 m精馏段 提馏段nxymxy10.95390.977910.57640.744420.91840.960220.50120.682530.86990.934630.40460.592540.80740.899840.29880.476950.73350.854850.20230.350360.65380.801760.12460.233570.57640.744470.07170.141880.03820.078590.01840.0384N =15〔包括釜〕NT

=6 N提

包括釜〕10)R=2.0Rmin 精馏段：y =0.730x +0.2643n1 n提馏段：y =1.1896x -0.0071m1 m精馏段 提馏段nxymxy10.95390.977910.56990.739220.91940.960620.48780.670930.87140.935530.38550.573240.80860.900440.27780.451550.73300.854650.18260.323460.65060.799460.11050.210170.56990.739270.06230.124480.03240.0670N =14〔包括釜〕NT

=6 N精 提

包括釜〕对上表塔板数列表：R=nRmin1.11.2 1.3 1.41.5 1.61.71.8 1.92.0精馏段1310 9 88 777 66提馏段1211 10 109 998 98N(含釜)N(含釜)25211918171616151514回流比与塔板层数关系图数层板塔262422回流比与塔板层数关系图数层板塔26242220181614121011.11.21.31.41.51.61.71.81.9 2R=nRmin此题取回流比R1.5R 1.51.352.025minN =17〔包括釜〕NT

=8

包括釜〕提查取塔板效率：t tt底 顶tln 底t顶

177.41141.48177.41ln141.48

158.77℃ A 20 B 20

()(t20)0.104166t()(t20)0.28392t x 0.590.104166 10.590.28390.1779L i iE 0.49 0.245T L

0.492.140.17790.2450.62NN 实

不含釜ET

1710.62

25.8四、 塔板构造计算〔设计塔顶第一块板〕计算塔顶实际的汽液相体积流量：AB

(20 t (20 t

)(t20)864-0.875×(141.48-20)=757.71Kg/m3)(t20)878-0.707×(141.48-20)=792.11Kg/m3液相密度计算：1 (xA)”(xB)” 0.975 10.975 L A B

757.71 792.11∴ 758.53 Kg/m3LM=0.9779×106＋(1－0.9779)×120＝106.3094kg/kmol PMV RT顶

8.314273.15141.48

3.12 Kg/m3L RDM/h

(2.0251)76.982106.3094/758.5321.85m3/hV (R1)DM/h

(2.0251)76.982106.3094/3.127934.72m3/h选取塔板间距H ：THT

＝0.45m HT

＝0.7m计算液汽动能参数C：L21.857934.72758L21.857934.72758.533.12V

0.043h选取板上液层高度hL

V=0.05m，HT

-h =0.45-0.05=0.40mL查史密斯关联图，查得汽相负荷参数C20液体外表张力的计算：

0.084 A 20 B 20

(t(t

)(t20)28.99-0.109(141.48-20)=15.75dyne/cm)(t20)28.93-0.101(141.48-20)=16.66dyne/cmxi i

15.750.9779+16.66(1-0.9779)=15.77dyne/cm 15.770.2CC (20 20

0.084 20

0.0801计算液泛速度UF

(U )：maxU CF

0.0801LLV

1.25m/s758758.533.123.120.7，则空塔气速UG选取溢流方式及堰长同塔径的比值lw

=0.7UF/D:

=0.71.25=0.875m/s选用单溢流弓形降液管，取l /D=0.7。查弓形降液管的参数图，查取降w液管面积同塔截面积的比值Af

/A=0.088，及降液管宽度同塔径的比T值W /D=0.14。d计算塔径：VA GG uG

7934.72/36000.875

2.52m2AT

G1A /A 4242.76A

2.76m24AT塔径：D4AT

1.88mD=1.8m。计算塔径圆整后的实际气速：A D2T 4

1.824

2.54m2A AG

A A )2.54(10.088)2.316m2f Tu Vs G AG

7934.72/36002.316

0.952m/suGuF

.9521.25

0762m/s 在〔0.6～0.8〕范围内D=1.8mlw

0.7D0.71.81.26m降液管宽度：Wd

=0.14D=0.141.8=0.252mAf

0.088AT

0.0882.540.2235m2五.hw

及堰上液层高度how

确实定选取溢流堰高度hw

=50mm

LhL w

=12.3lw

/D=0.7得液流收缩系数E=1.023

=0.0028EL

0.019how∴h =h +h =50+19=69mmL w ow板面筛孔布置的设计：选取筛孔直径d=5mm。o

h LwL筛孔按正三角形排列，孔中心距孔径=3,孔中心距t=3d0=3×5=15mm选塔板厚度tp=3.5mm〔碳钢板。计算开孔区面积A ：aA =A －2A =2.54－2×0.2235＝2.093m2a T f开孔率：=A =0.907d 2=0.907×12=0.101=10.1% o o A t 3a开孔面积：A=Ao

=0.101×2.093=0.2114m2气体通过筛孔的流速：U

=Vso Ao

=7934.72/36000.2114

=10.4262msN=Ao

=10772d24 o七． 学性能参数计算及校核液沫夹带分率的检验0.057 Ue G

=0.0123kg/kg＜0.1kg/kg气G H 2.5hT w

h ow故在本设计液沫夹带量eG塔板压降干板压降

在允许范围内。由d 5mm t0

35mm故d0

/t =5/3.5=1.43,查干筛孔的流量系数表，p得孔流系数c0

=0.781 U 2h o Vo

=0.03746m2g Co L液层静压降通过有效传质区的气速：u

Vs 7934.72/3600

0.9515ma A A121212123.12

2.540.2235 s气相动能因子：F u0 a

0.9515V

1.7kg

/(sm )查充气系数关联图，得充气系数=0.58。h hL

h =0.58×0.069=0.04002mow液层外表张力压降4103h

gdL

=0.0017m单板总压降Hh h h =0.03746+0.04002+0.0017=0.07948mo L全塔总压降P P HN底 顶

=760＋0.0791810313.6

910.2091mmHg液面落差的校验：对于筛板塔，液面落差很小。本设计塔径和液流量均不大，可无视液面落差影响塔板漏液状况的校验产生漏液的干板压降h”0.00510.05ho

h =0.00855mow工作状态下2稳定系数k2

h =o o=

=2.09>1.5U ” h”o o故不会产生严峻漏液。降液管液泛状况的校验：选取降液管下缘至下层塔板的距离h：0则降液管下缘缝隙通道的截面积A =hda

l =0.02×1.26=0.0252m2w液体流出降液管的阻力损失h ：d1.39 V

21.85/36002h (d g A

da

9.81

0.0252

0.00823mH”：dH =Hd

+h +hw

++hd=0.03746+0.04002+0.069+0+0.00823＝0.1547m二甲苯—三甲苯物系属一般物系，取=0.5，H则H” H

=0.1547

0.3094md 校核：

0.5H +hT w

=0.45+0.05=0.5m ∴H”d

H hT w故在本设计中不会发生液泛现象。液体在降液管内停留时间的校验：3600AH f Lh

=36000.22350.154721.85

5.7s>3s故降液管设计合理。八. 塔板负荷性能图(一)负荷性能图过量液沫夹带线L 2 L1 V

3V 8812A G G

3.2HT2.5hw0.0028E

Lw = 1

2 V 3 2 LL88122.31615.77

0.452.50.0050.00281.023 1.26 23=15704.308-296.61723L最大气相负荷线以=3sAfHd=3得V

AfHd

0.22350.1547

Lsm3h41m3hL 3/3600 3/3600最小液相负荷线

0.006

L =

0.006 32 L 0.0028E w 0.00281.023最小气相负荷线0.5 2 L V 3 LV 15946CG

L A0.00560.13 h 0.0028E h o w V

L w 0.5 2 =159460.78758.53 0.21140.00560.130.0050.00281.023V 30.0017L 3.12

1.26 00.01040.0004344V23L

降液管液泛线A 0.02Lda

0.02520.5 2

20.