matlab作图法计算精馏理论板数

1、MATLAB图解法计算精馏塔理论板数 中文摘要：双组份精馏是化工生产中重要的单元操作，运用matlab【1】的强大功能，通过绘制精馏段和提留段操作线方程以及进料q线方程，运用图解法计算理论板数和进料板位置，使得求解精确、简洁。中文关键词：matlab 精馏 理论板 图解法Title：Graphical Method MATLAB number of theoretical distillationAbstract：Two-component distillation is an important chemical production unit operations, using the p

2、ower of matlab, by drawing the rectifying section operating line segment and the retention equation and the feed q line equation, the use of graphical method to calculate the theoretical plate number and location of the feed plate Makes solving the accurate, concise朗读显示对应的拉丁字符的拼音 字典Keywords：Mat

3、lab Distillation Theoretical plate Graphic引 言 二元精馏塔的计算可用图解法计算理论板数。通过函数求解曲线绘制，采用图解法计算理论板数。在工程计算中matlab语言拥有大量的命令集和可用函数集可以完成各种计算和数据处理，集数值计算和图形处理功能于一身，形式简单，易于掌握。1 问题叙述：常压操作的的连续精馏塔，分离含二硫化碳0.53（摩尔分数）的二硫化碳四氯化碳混合液，要求塔顶产品中含二硫化碳不低于0.986，塔底产品中含二硫化碳不高于0.0220.操作回流比为3.8，计算进料液相分率为1.550时的理论板层数和加料板位置。常压下的二硫化碳和四氯化碳的气

4、液平衡数据【2】液相中二硫化碳摩尔分率x气相中二硫化碳摩尔分率y液相中二硫化碳摩尔分率x气相中二硫化碳摩尔分率y00.02960.06150.11060.14350.258000.08230.15550.26600.33250.49500.39080.53180.66300.75740.86041.00.63400.74700.82900.87900.93201.02 数学模型：精馏段操作线方程：提馏段操作线方程：相平衡方程：q线方程：3解决问题方法：1、列出已知条件2、用line绘出对角线，拟合数据用plot绘制平衡线3、利用fplot绘制精馏段操作线4、利用fplot绘制进料线5、求3,4

5、两线交点f，采用数值解法，调用fzero6、连接f与塔底组成点c绘制提馏段操作线7、绘制阶梯，计算理论板数给定，R，F框图绘制对角线，拟合气液平衡数据绘制平衡线绘制精馏段操作线方程绘制进料线方程联立两直线求交点绘制提馏段操作线绘制阶梯，求理论板数具体程序【1，2】如下：%图解法确定精馏塔理论板层数function fdistillation%图解法确定理论板层数clear,clc%1.已知数据xD = 0.986;%塔顶组成xW = 0.0220%塔釜组成xF = 0.53;%进料组成R = 3.8;%回流比q = 1.550;%进料热状况vledata = %汽液平衡数据0 0.0296 0

6、.0615 0.1106 0.1435 0.2580 0.3908 0.5318 0.6630 0.7574 0.8604 1.00 0.0823 0.1555 0.2660 0.3325 0.4950 0.6340 0.7470 0.8290 0.8790 0.9320 1.0;%2 绘制平衡线plot(vledata(1,:),vledata(2,:),'*')hold on p = polyfit(vledata(1,:),vledata(2,:),3);x1 = 0.0 :0.01:1.0;y1 = polyval(p,x1);plot(x1,y1)hold on %3

7、 绘制对角线line(0.0,1.0,0.0,1.0)% 4 绘制精馏段操作线fplot(recope,0 xD,'r',R,xD)hold on % 5 绘制进料线方程fplot(qline,xF 1,'g',q,xF)hold on % 6 与进料线的交点xc = fzero(cross,0.5,optimset('fzero'),R,xD,q,xF);yc = recope(xc,R,xD);% 7 绘制提馏段操作线line(xc,xW,yc,xW,'Color','c')% 8 绘制梯级x0 = xD;y0

8、 = xD;n=0;while 1n = n+1;x0,y0 = tri(x0,y0,R ,xD,p ,xc ,yc,xW,n);if x0<xWbreak;endend% 9修饰s = sprintf('理论板数为%d',n);text(0.1,0.9,s)xlim(0,1),ylim(0,1),title('图解法确定精馏塔理论板数'),xlabel('x'),ylabel('y')%-精馏段操作线-function y = recope(x,R,xD)y = R*x/(R+1)+xD/(R+1);%-进料线方程-fun

9、ction y = qline(x,q,xF)y = q*x/(q-1)-xF/(q-1);%-交点-function y = cross(x,R,xD,q,xF)y = recope(x,R,xD)-qline(x,q,xF);%-平衡关系逆运算-function y = vlei(x,p,yn)y = polyval(p,x)-yn;%-绘制梯级-function x,y = tri(x0,y0,R,xD,p,xc,yc,xW,n)x = fzero(vlei,x0,optimset('fzero'),p,y0);if x>xcy = recope(x,R,xD);e

10、lsey = yc + (yc-xW)*(x-xc)/(xc-xW);endline (x0,x,x,y0,y0,y,'Color','m'),text(x,y0,int2str(n),'VerticalAlignment','bottom')grid on结果如下：由图可以看出需要12块理论板结论：应用 matlab求解二元精馏塔理论板数，方法简单实用，可以方便快捷的得到计算结果。参考文献1 田文德，王晓红.化工过程计算机基础.北京：化工过程计算机应用基础.北京：化学工业出版社20072 陈敏恒，丛德滋，方图南等.化工原理.第3

11、版.北京：化学工业出版社200600.01000000000000000.02000000000000000.04000000000000000.06000000000000000.08000000000000000.1000000000000000.1400000000000000.1800000000000000.2000000000000000.2500000000000000.3000000000000000.3500000000000000.4000000000000000.4500000000000000.5000000000000000.5500000000000000.6000

12、000000000000.6500000000000000.7000000000000000.7500000000000000.8000000000000000.8500000000000000.8940000000000000.9000000000000000.950000000000000100.1100000000000000.1750000000000000.2730000000000000.3400000000000000.3920000000000000.4300000000000000.4820000000000000.5130000000000000.5250000000000000.5510000000000000.5750000000000000.5950000000000000.6140000000000000.635000000000