万吨甲醇精馏工艺计算97

1、1 / 1315万吨甲醇精馏工艺计算1、 主塔塔板数的计算 .由所提供的资料知D=20t/h,出塔甲醇含量为99.9827%塔釜含量为0.03%, 进塔为82%,并可计算以下数据xD = =0.9997xW= =0.000169xF= =0.720= = =0.72 F= t/h=27.78t/hW=F-D=7.78t/hNm= = = =1.5420Nm= =38.78 39当 q=1 时, x1= xFye= = =0.799由 = 可知 Rmin= = =2.54R=1.5Rmi n,二=0.2625根据吉利兰联图查得 =0.45 =0.45, N=71.72 72 块2、2 / 13主

2、塔塔径的计算：L=RD=3.8X20t/h=76000kg/h. M=76000/32=2375kmol/h.V0=2375X22.4=53200Nm3/h操作状态下体积： V1= =55041.82 Nm3/h气体负荷 Vs=55041.82/3600=15.3 Nm3/s液体负荷 Ls=76000/3600=21.11 kg/st= =74.5C当 t=745C时，100%甲醇密度为 0.796kg/m3Ls=21.11/0.796=26.52 L/s=0.02652m3/s气体密度：丫 v=7.6x104/53200=1.43kg/m3液体密度：74.5C时，丫 L=796Kg/m3FL

3、V= =0.04174.5C时，（甲醇=17.7X0-5N/cmo水=65X0-5N/cm平均组成甲醇 =C =2.23 m/s取泛点的百分率为 80%，表观空塔气相速度 ug(max, u=0.8 ug(max =0.8x2.23=1.784m/s ,D = = =3.31m去塔径为 3.4m. 操作空塔气速 u= =1.686m/s初步核算雾沫夹带取 lW=0.7D=0.7x3.4m=2.38mAT=nD2/4=0.785x(3.42=9.0746m2查得 Af/AT=0.0878,二 Af=0.878AT=9.0746X0.878=0.8m2ug= = =1.84m/s.hf=2.5hc

4、 =0.175mev=0.22x( 3.2= ( ( 3x.2=(x3.2=0.061 kg/kg 汽 5S从以上两相核算初步认为塔径可取 3.4m 是合适的.(2塔板结构型式确定采用单流型 .因为 LS=0.02652m3/s=94.5 m3/h堰及降液管设计堰长: lw=0.7D=2.38m求 how= =10.93查得 E=1.03.how=0.00284E( 2/3=0.00284 1.03 冬2/3=0.0343m求液面的梯降B=(lw+D/2=(2.38+3.4/2=2.89m查得 Wd=0.143D=0.4862m=0.35cpZ 仁 D-2Wd=3.4-2 0.4862=2.4

5、276mhf=2.5hL=2.5 0.07=0.175m.=0.0001364(可忽略求 hL 设 h/L=0.07m故 hW=h/L- how=0.07-0.0343=0.0357m取 hW为 40mm.贝 U hL=hW+ how=0.04+0.0343=0.0743m h/L(h/啲假设值合理再求 ho5 / 13假设 ho比 hW低 13mmho= hW-0.013=0.04-0.013=0.027m故取 ho=25mm(4筛孔布置取 d0=4mmt/d0=3.5 则 t=14 mm由图查得 AO/Aa=0.074 即开孔面积与开孔区面积之比取 WS=0.1m, WC=0.08 mX/

6、 丫 =(1.57/1.45=0.94由图得Aa=4.5m2.由图得 n =600 个/ 川n=6000 4.5=27000 个(5干板压降取 =3mm, =1.33.由图得 CO=0.84hc=0.0512 ( 2( =0.2752 m 液柱(6稳定性h= = =0.00311 液柱Uom=4.4CO6 / 13=4.4 (X84=9.388m/sK= 取实际的孔速为 15 m/s则 K= =1.60即按漏夜气速考虑的负荷下限为设计负荷的(7降液管内液泛可能性FO=uO=15 =17.94由图得 h1=0.045 液柱贝 U hp=hC+ h1=0.2752+0.045=0.3202 m 液

7、柱(8降液管内液泛可能性Hd=hL+hd+hphd=0.153( 2=0.153( 2=0.0304m 液柱Hd=0.07+0.0304+0.3202=0.4206 m 液柱/= =15.15s故不可能产生降液管内液泛(9雾沫夹带量核算 ev=0.22 & 3.2= ( ( 3 星62.54%7 / 13=( (3.2=0.0681kg/kg 汽负荷上限当 ev=0.1 时,ugmax=2.085 m/sugmax/ug=2.085/1.849=1.13即负荷上限为设计值的 113%。将上述计算数据整理成表，如下:序号项目数值1塔径 D3.4m2塔板间距 H0.5m3塔板型式单流型4空

8、塔气速度 u1.686m/s5堰长 lw2.38m6外堰咼 hw0.04m7板上清液层咼度 hl0.0743m8降液管底与板距离 ho0.025m9孔径 do4mm8 / 1310孔间距 t14mm11开孔区边缘与塔壁距离 WO0.08m12开孔区边缘与堰距离 WS0.1m13孔数 n27000 个14开孔区宽 2x3.04m15开孔面积 AO0.333m216塔板压降0.2752m 液柱17液体在降液管中停留时间T15.1s18降液管内清液层高度 Hd0.4206m19雾沫夹带 ev0.0681kg/kg 汽20负荷上限 雾沫夹带控制）113%21负荷下限 漏液控制）62.54%3冷凝器计算

9、：9 / 13(1 试算和初选换热器的规格1计算热负荷和冷却水流量 查 Cp 甲醇=0.68kcal/kgGCP 水=4.187KJ/KgGQ=WhCph(T1-T2-20000X0.684.1868 采 03/3600=5.22 105 WW= = =5.62 104kg/h2计算两流体的平均温度差 ,暂按单壳程 ,多管程进行计算 ,逆流时平均温度差m= = =14.43G而 P= = =0.21.R= = =4.125由参考书上的图查的 =0.75.所以 Atm=At Atm=0.75 为 4.43G 10.8225.3初选换热器规格 .根据两流体的情况 .假设 K=450W/(m2 G故

10、S= = =107.2.由此查的管子的总根数为 232 管子尺寸为 2542.管长 6m,壳径600mm,管程数为 2.实际换热面积 S0=nndL23243.141640.025-0.(6=107.45K0= = =449 W/(m2GK0 与假设相符,所以传热系数为 450W/(m2G.(2 核算压强降 .10 / 131管程压强降EPi=(AP1+AP2FtNP其中 Ft=1.4, NP=2.管程流通面积 Ai=n/4 X di2X=n/4 X (0.022 X =0.0364m2ui= = =0.43m/sRei= = =11758.5(湍流设管壁粗糙度=0.1mm, = =0.005

11、 由-Re 关系图查得=0.034.所以仲仁=0.034X937.3PaP2= = =275.97 Pa2壳程压强降 .EP0=(AP1z+2tNs其中 FS=1.15, NS=1.API =Onc(NB+1管子为三角形排列 ,所以 F=0.5.nc=1.19 =1.19 =18.1319取折流挡板间距 h=0.15m.NB= 1= 1=39.11 / 13壳程流通面积 AO=h(D ncdo=0.15 (0.6-19 0025=0.01875m2.u0= =0.37m/sRe0= = =11327.7500f0=5.0 Re0-0.228=5.0 11327.7-0.228=0.595所以

12、AP1 =0.4X0.595X19X(39+1X=2879.6Pa.P0=(2879.6+1862.64 1XI5=5453.576Pa.(3核算总传热系数 .管程对流传热系数Rei=11758.5(湍流 Pri= = =4.86=0.023Rei0.8 Pri0.4=0.023 魁为 758.50.8X；4.860.4=2444.6W/(m2C壳程对流传热系数=0.36( ( 0.55Pr1/3( 0.1412 / 13取换热器列管的中心距 t=32 mm.则流体通过管间最大截面积为 A=hD(1-=0.16 (X6(1- =0.0197m2.ue= = =0.3543.de= =0.027m.Re0= = =11714.8Pr0= = =7.6壳程中甲醇被冷却 ,取( 0.14=0.95,所以=总 1714.80.55(7.61/3