[年产十万吨二甲醚装置分离精馏工段的工艺设计]
根据以上数据，查史密斯关联图C20?0.054。由于物系表面张力为30.62dyn/cm,不接
???近C20,需要校正：C?C20??20??0.2?30.62??0.054??20??0.2?0.06400
umax?C??L??V?/?V?0.064?847.1?2.894?/2.259?1.164(m/s)
取安全系数为0.7，则u?0.7umax?0.815m/s 塔径：D?4Vs/?u?4?1.254/3.14?0.8150?1.397m
按标准塔径圆整为D=1.4m，则塔面积：A=1.539(m)
空塔气速：u=0.8146（m/s） (3)提馏段计算：
?Ls'???L'???V'?????'???s??V?0.5?0.12685??922.8??????4.72031.148????0.5?0.7619取塔板间距HT'?400mm及板上液层
高度hL'?0.09m，则：HT'?hL'?0.4?0.09?0.31m
根据以上数据，查史密斯关联图C20'?0.02599。由于物系表面张力为54.30dyn/cm,
???不接近C20’,需要校正：C'?C20'??20??0.2?54.30??0.02599??20??0.2?0.0317
umax'?C'??L'??V'?/?V'?0.03174?922.8?1.148?/1.148?0.899(m/s)
取安全系数为0.7，则u'?0.7umax'?0.6295m/s 塔径：D'?4Vs/?u?4?1.416/3.14?0.6295?1.693m
按标准塔径圆整为D=1.8m，则塔面积：A=2.545(m)
空塔气速：u’=0.5565（m/s）
2.3.4塔板结构设计
（一）精馏段
板间距 HT=0.35m,取板上液层高度hL=0.07m 塔径D=1.4m
根据塔径和液体的流量，选用弓形降液管，不设进口堰，塔板采用单溢流和分块式组装。
(1) 溢流装置 ① 堰长lW
取堰长lW=0.65D，即lW=0.65×1.4=0.91（m） ② 堰上液层高度hOW
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[年产十万吨二甲醚装置分离精馏工段的工艺设计]
how?0.00284?1.02?7.680/0.91?③ 出口堰高：hw?hL?how
2/3?0.011990782m?0.006m
符合要求。一般要求堰上液层高度不小于6mm，以免液体在堰上分步均匀。
hw?hL?how?0.07?0.01199?0.05801m
④ 降液管的底隙高度ho
液体通过降液管底隙的流速一般为0.07~0.25m/s，取液体通过降液管底隙的流速
??0.08m/s，则有： uoho?Ls0.009143 ??0..12559m（ho不宜小于0.02~0.025m，本结果满足要求）
?0.91?0.08lwuo
⑤降液管的宽度Wd和降液管的面积Af由lw/D?0.65，查化原下P147图11-16得Wd/D?0.126,Af/AT?0.07，即：
Wd?0.1764m，AT?0.785D2?1.5386m2，Af?0.107702m2。
⑥液体在降液管内的停留时间
??AfHT/Ls?0.1077?0.35/0.009143?4.12282s?5s（不符合要求）
故重新修正参数选取：HT=500mm 此时
） ??AfHT/Ls?0.1077?0.5/0.009143?5.889752s?5s （符合要求。
（3） 塔板布置及浮阀数目排列：
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[年产十万吨二甲醚装置分离精馏工段的工艺设计]
浮阀排列方式采用等腰三角形叉排。
2.4浮阀塔提溜段与精馏段设计参数汇总
提留段与精馏段的算法一致，结果见后总表。
表2-22 浮阀塔工艺设计计算总表 塔径D,m 塔高H,m 塔板型式 塔板数（层） 空塔气数u,m/s 堰长l,m 堰高h,m 降液管底隙高度ho,m 浮阀数N，个 阀孔气速u,m/s 阀孔动能因数Fu 临界阀孔气速m/s 孔心距 t,m 排间距 t’m 单板压降 Pa 液体在降液管内清液层高度 H,m 液体在降液管内停留时间θ,s 泛点率％ 33数值及说明 精馏段 提馏段 备 注 气相负荷上限（VS）max,m/s 气相负荷下限（VS）min,m/s
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[年产十万吨二甲醚装置分离精馏工段的工艺设计]
Annual output of 10,000 tons of dimethyl ether distillation
Section in the design of sepration device
INTRODUCTION
Motor Vehicle population is increasing in China,and the country is faced with a serious energy supply problem. China’s smaller reserves of petroleum and risingdemand for petroleum products result in a net import postion which is not likely to be reversed. Therefore,strong effeorts should be made to find commercially viable alternatives to imported oil and oil products for automobiles to satisfy the short-and medium-term needs of the country. DME is one of the promising fuel substitutes for petroleum diesel fuel which can be used by compression ignition engines because it is a clean fuel with good self-ignition characteristics and almost smoke-free combustion. Numerous investigation of DME-fulled engines have indicated that DME offers an excellent promise as an alternative fuel for compression-ignition operation in the automotive sector with its ultra-low emissions.
The use of dimethyl ether(DME)as an alternative fuel appears to be a promising approach for simultaneously minimizing NOx and soot emission from conventional diesel engines. The low self-ignition temperature of 508K and the high oxygen content
Of 34.8 percent(mass fraction) are two major factors characterizing low soot and unburned total hydrocarbon(THC)emission
Preparation of dimethyl ether mainly methanol dchydration and One-step synethesis. With the tradional methanol synethesis compared to synethesis of dimethyl ether,one-step synethesis of dimethyl ether process more rational economy, more competive in the market and it is moving towards industrialiazation. Curently , synethesis gas to dimethyl ether is the latest technology preparation of dimethyl ether. Compared with methanol dchydration , system of direct synthesis of DME as the existence of unreacted synthesis gas and carbon dioxide finished.If it want to get high purity dimethyl ether, more complicated separation process. Developed mainly in the separation process such as chemical absorption and distillation unit operation in the process of dimethylethyl ether with higher purity product.This design aimed at separating the distillation process for process design. Separation of DME , methanol and water ternary system. Design of distillation towers used valve. Use the whole top of the tower condenser cooling device used to provide sufficient heat.Obtained by calculating the number of theoretical plate design and calculation of process dimensions derived column diametet, the effective tower, sieve number. Checking through the sieve of fluid mechanics, to prove that the indicator data are in line with standards to ensure the smooth progress of distillation process and to improve efficiency as much as possible.
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