菜单
  

    tion method developed for multicomponent, homogeneous
    mixtures has been generalized to include heterogeneous
    mixtures [9].
    3. Distillation column design
    Residue curve maps (RCMs) are very useful for the
    characterization of azeotropic mixtures, predicting feasible
    splits, selecting entrainers, and analyzing potential column
    operability problems [2–5,10,11]. They display the shape
    of the separation space, including distillation boundaries,
    distillation regions and azeotropes. Residue curves areequivalent to the composition profiles of infinitely long
    packed column at total reflux (continuous model described
    by differential equations). Composition profiles of staged
    column at total reflux (discrete model described by finite
    difference equations), can be approximated by simple dis-
    tillation residue curves and usually the differences between
    these two types of curves are small [2]. Using residue curve
    maps, infeasible specifications can be immediately identi-
    fied, and alternative distillation sequences can be inferred
    without trial and error. The shapes of residue curves are
    very useful in the design of real finite reflux separators since
    they give a qualitative picture of the composition profiles
    in actual staged towers.
    In this paper, we use the boundary-value design method
    (BVDM) [11] for the distillation column design. For a
    one-feed, two-product distillation column, we define the
    feed, specify completely distillate and bottoms (using com-
    ponent and overall mass balances) and select the column’s
    internal flows (by specifying reflux or reboil ratio and using
    an energy balance). The composition profiles are then cal-
    culated using a combination of flashes and mass balances
    starting from both ends. If the composition profiles for
    rectifying and stripping sections of the column cross in the
    composition space, the column is feasible and the number
    of stages in each section of the column can be counted.
    The BVDM algorithm for a ternary one-feed two-product
    distillation column can be summarized as follows:
    1. Specify feed composition and thermodynamic state.
    2. Specify column pressure.
    3. Specify three of six possible products’ mole fractions.
    4. Calculate the remaining products’ mole fractions using
    mass balances.
    5. Guess a value for the reflux ratio.
    6. Calculate reboil ratio using energy balance.
    7. Compute the composition profiles for the rectifying and
    stripping sections of the column starting from distillate
    and bottoms compositions.
    8. Repeat (5)–(7) until composition profiles intersect in the
    composition space.
    9. Repeat (2)–(7) to optimize reflux ratio and pressure.
    10. Count the number of stages in each section of the
    column.
    For distillation columns with top decanter, a side stream
    draw or two feeds, the algorithm requires modifications.
    These modifications will be explained within the following
    examples. P, column pressure
     r, reflux ratio
     s, reboil ratio
     q, feed quality
     n, number of stages in the column
     f, feed stage location
    These variables are related by 3 summation equations for
    mole fractions in each stream, c−2 co-linearity conditions
    between x x xB and x x xD (derived from mass balances), and one
    condition between r and s (energy balance). The BVDM
    makes it possible to compute the rectifying composition pro-
    file starting from the distillate composition, and the stripping
    profile starting from the bottoms composition. The distilla-
    tion column will be feasible only if the profiles intersect in
    the composition space. The point of intersection represents
    the composition of the liquid stream leaving the feed stage
  1. 上一篇:管壳式换热器进行污垢分析英文文献和翻译
  2. 下一篇:建筑施工混凝土裂缝预防处理英文文献和翻译
  1. 船舶结构优化设计英文文献和中文翻译

  2. 船舶设计问题上的新全局...

  3. 船体初步设计中的船型优...

  4. SWATH的参数化设计和多目标...

  5. 拉削工具设计的优化英文文献和中文翻译

  6. 焊接或螺栓连接角节点的...

  7. 驱动桥优化设计英文文献和中文翻译

  8. 中考体育项目与体育教学合理结合的研究

  9. 当代大学生慈善意识研究+文献综述

  10. 大众媒体对公共政策制定的影响

  11. 杂拟谷盗体内共生菌沃尔...

  12. 酸性水汽提装置总汽提塔设计+CAD图纸

  13. 乳业同业并购式全产业链...

  14. java+mysql车辆管理系统的设计+源代码

  15. 电站锅炉暖风器设计任务书

  16. 河岸冲刷和泥沙淤积的监测国内外研究现状

  17. 十二层带中心支撑钢结构...

  

About

751论文网手机版...

主页:http://www.751com.cn

关闭返回