一、确定流程(画图) 二、物料衡算
xF?22.08% xD?88.14% xW?0.3937% M?0.2208?46?(1?0.2208)?18?24.18g/mol
F?4800kg/h?198.51kmol/h F?D?W FxF?DxD?WxW
24.18g/molD?49.06kmol/h W?149.45kmo/lh
三、确定塔板数(q=1) (见CAD出图)
Rmin?0.8081 ? Rmin?4.211 R?1.5Rmin?6.316 5Rmin?1理论板:NT?44(包括再沸器) NF?41
实际板:N?85(不包括再沸器) N精馏?80 N提馏?5 N加料?81 四、精馏塔的工艺条件及有关物性数据的计算 1、气液相负荷
L?RD?309.89kmol/h L??L?F?508.40kmo/lh
V??V?(R?1)D?358.95kmol/h
2、操作压力(单板压降?p?0.7KPa)
塔顶操作压力:P.3?4?105.3KPa 设?p?0.6KPa 1?101第80快板:P80?105.3?0.6?79?152.7KPa 进料板压力: P81?105.3?0.6?80?153.3KPa 塔底操作压力:p85?105.3?0.6?84?155.7KPa
? 精馏段平均压力P?P105.3?152.71?P80??129KPa 22P?P153.3?155.7?154.5KPa 提馏段平均压力P??8185?223、操作温度 塔顶采用全凝器
塔顶温度:由P.3KPa,查得t1乙醇?79.2?C,t1水?100.95?C 1?105乙醇x1?0.8803,x1水?1-0.8803?0.1197
?t1?0.8803?79.2?0.1197?100.95?81.80?C
第80快板温度:由P80?152.7KPa,查得t80乙醇?89.2?C,t80水?111.70?C
乙醇x80?0.4695,x1水?1-0.4695?0.5305
?t80?0.4695?88.5?0.5305?111.70?100.81?C
第81快板温度:由p81?153.3KPa,查得t81乙醇?89.4?C,t81水?111.81?C
乙醇x81?0.1902,x81水?1-0.1902?0.8098,
?t81?0.1902?89.4?0.8098?111.81?107.55?C
塔底温度:由P85?154.5KPa,查得t85乙醇?89.9?C,t85水?112.35?C
乙醇x85?0.004085,x85水?1-0.004085, ?0.995915?t85?0.004085?89.9?0.995915?112.35?112.26?C
?精馏段平均温度t?t1?t8081.80?100.81??91.31?C 22t?t107.55?112.26?109.91?C 提馏段平均温度t??8185?224、平均摩尔流量
塔顶:由y1?xD?0.8814查得x1?0.8803
MV1m?0.8814?46?(1?0.8814)?18?42.68kg/kmol ML1m?0.8803?46?(1?0.8803)?18?42.65kg/kmol
第80快板:由x80?0.4695查得y80?0.6395
MV80m?0.6395?46?(1?0.6395)?18?35.91kg/kmol ML80m?0.4695?46?(1?0.4695)?18?31.15kg/kmol
进料板81:由x81?0.1902查得y81?0.5258
MV81m?0.5258?46?(1?0.5258)?18?32.72kg/kmol
ML81m?0.1902?46?(1?0.1902)?18?23.33kg/kmol
塔底:由x85?0.004085查得y85?0.046914
MV85m?0.0469?46?(1?0.0469)?18?19.31kg/kmol ML85m?0.004085?46?(1?0.004085)?18?18.11kg/kmol
?精馏段平均摩尔流量:MVm?42.68?35.91?39.30kg/kmol 242.65?31.15MLm??36.9kg/kmol
232.72?19.31???26.02kg/kmol 提馏段平均摩尔流量:MVm223.33?18.11??MLm?20.72kg/kmol
25、平均密度 1)气相平均密度 精馏段:?Vm???提馏段:?VmpMVm129?39.30??1.67kg/m3 RT8.314?(91.31?273.15)?P?MVm154.5?26.02??1.26kg/m3 RT?8.314?(109.91?273.15)2)液相平均密度 据
1?Lm?x?A?A?x?B?B?x?C?C????x?n?n
塔顶:由t1?81.80?C查得?A?0.736g/cm3 ?B?970.63kg/m3
??L1m?1?745.096kg/m3
0.94951?0.9495?736970.63第80快板:由t80?100.81?C查得?A?0.713g/cm3,?B?957.80kg/m3
??L80m?1?773.623kg/m3
0.69341?0.6934?713957.80进料板:由t81?107.55?C查得?A?0.707g/cm3,?B?952.813kg/m3
??L81m?1?842.887kg/m3
0.37511?0.3751?707952.813塔底:由t85?112.26?C查得?A?0.691g/cm3,?B?949.215kg/m3
1?945.540kg/m3
0.01041?0.0104?691949.215745.096?773.623?759.36kg/m3 ?精馏段液相平均密度?Lm?2842.887?945.540???894.21kg/m3 提馏段液相平均密度?Lm2??L85m?6、液相平均表面张力
塔顶:由t1?81.80?C查得?A?17.1mN/m,?B?62.26mN/m
?L1m?1xAxB?1?47.31mN/m
0.88031?0.8803?62.2617.1?B??A第80快板:由t80?100.81?C查得?A?15.4mN/m,?B?58.65mN/m
?L80m?1xAxB?1?23.56mN/m
0.46951?0.4695?58.6515.4?B??A进料板:由t81?107.55?C查得?A?14.2mN/m,?B?57.37mN/m
?L81m?1xAxB?1?16.57mN/m
0.19021?0.1902?57.3714.2?B??A塔顶:由t85?112.26?C查得?A?14.1mN/m,?B?56.43mN/m
?L85m?1xAxB?1?14.41mN/m
0.0040851?0.004085?56.4314.1?B??A?精馏段液相平均表面张力?Lm?47.31?23.56?35.44mN/m 216.57?14.41???15.49mN/m 提馏段液相平均表面张力?Lm2五、精馏塔的塔体工艺尺寸计算 1、塔径
1)精馏段
气相体积流量Vs?液相体积流量Ls?VMVm358.95?39.30??2.34m3/s
3600?Vm3600?1.6731LMLm309.89?36.9??4.18?10?3m3/s
3600?Lm3600?759.360u?(0.6~0.8)umax,umax?C?L??V?,C?C20()0.2 ?V20取塔板间距HT?0.45m,板上液层高度hL?0.10m
Ls?Lm124.18?10?3759.3612由()??()?0.0381及HT?hL?0.35m Vs?Vm2.341.67查史密斯关联图得C20?0.074
?C?C20(?Lm20)0.2?0.074?(35.440.2)?0.083 20?umax?C?Lm??Vm759.36?1.67?0.083??1.77m/s ?Vm1.67取安全系数为0.7,则u?0.7umax?0.7?1.77?1.24m/s 则精馏段塔径D?4Vs4?2.34??1.55m ?u??1.24(?)D24Vs?2.34(?)?1.624?1.16m/s
取塔径D=1.6m,则塔空速u??则
u?1.16??0.66,符合安全系数在(0.6~0.8)之间 umax1.772)提馏段
气相体积流量Vs??液相体积流量Ls???V?MVm358.95?26.02??2.06m3/s ?3600?Vm3600?1.26?L?MLm508.40?20.72??3.27?10?3m3/s ?3600?Lm3600?894.21取塔板间距HT?0.45m,板上液层高度hL?0.10m
??Lm?123.27?10?3894.2112Ls由()??()?0.0423及HT?hL?0.35m
??Vs?Vm2.061.26