英文翻译1

Distillation 蒸馏

Separation operations achieve their objective by the creation of two or more coexisting zones which differ in

molecular species in the mixture to be separated reacts in a unique way to differing environments offered by these

分离过程通过形成在温度、压力、组成和相态上有区别的两个或多个共存区来达到它的目的。每一种待分离的在混合物中的分子种类以一种独特的17方式与这些区域提供的不同的环境相互作用。结果是随着系统向平衡移动每个物质都在每个区域形成不同的浓度这样就可以使这些物质的到17分离。

The separation operation called distillation utilizes vapor and liquid phases at essentially the same temperature and pressure for the coexisting ordered packings and plates or trays are used to bring the two

other and enclosed in a cylindrical shell to form a lly contained in a cylindrical shell between hold- 利用在共有区中拥有相同温度和压力的汽油和液相的分离操作叫做分离。不同种类的装置例如规整填料和乱堆整料和塔板或塔盘被用来使两相充分接触。塔盘是一个堆着一个排列的并且被装入到一个圆柱形的外壳中形成一个塔。填料通常也被装入一个在压具板和支撑板之间的圆柱形外壳中。 1 Continuous Distillation The feed materof the difference in gravity between vapor and liquid phases, liquid floats up the col 1、连续蒸馏 将要被分离成馏分的进料通过一个或多个沿着管壳的点被引入到塔中。由于气相和液相之间重力的不同液体在塔中从一个塔盘到另一个塔盘呈阶梯形向下流动。同时气体在塔中向上流动并与液相在每个塔盘接触。

Liquid reaching the bottom of the column is partially vaporized in -ent back up the

of this liquid is returned to the column as reflux to provide liquid overflow. The remainder of the overhead stream is withdrawn as distillate, or overhead product. 液体到达塔底被一个加热的再沸器部分汽化来提供蒸汽。蒸汽重新返回塔中。塔底的残余物作为釜液或塔底产品被取出。达到塔底的气相在塔底冷凝器中被冷却并冷凝成液体。部分被冷凝的液体回流到

塔中从而提供液体溢流。塔顶馏分的剩余物作为馏分或塔顶产品被取出。 This overall flow pattern in a distillation column provides countercurrent contacting of vapor and liquid stream on all the trays extent dependent www.docin.comupon the efficiency of the 在蒸馏塔中的整个流动模式为气相和液相提供了一个在每一个塔盘逆流接触的机会。气相和液相在特定的塔盘上达到热量压力以及组成的平衡这在一定程度上取决于接触的塔板的效率。 The lighter(lower-boiling)components tend to concentrate in the vapor phase, while the heavier(higher-boiling)components tend

and a liquid phase that becomes richer in heavy components as it cascades downward. The overall separation achieved between the

volatilities of the components, the number of contacting trays, and the ratio of the liquid—phase flow rate to the vapor-phase flow rate. 低沸点的轻组分倾向于气相中富集而同时高沸点的重组分倾向于在液相中富集。这个结果是当它沿着塔向上移动的时候气相变得富含轻组分而当液体沿着塔积极向下移动的时候液相变得富含重组分。要在塔顶产品和釜液之间达到整个分离主要依赖于组分的相对挥发度接触塔盘的数目和液相和气相流动的比例。 If the feed is introduced at one point along the column shell the

rectifying section, and a the stripping section. These terms become rather indefinite in multiple-feed columns and columns from which a product sidestream is withdrawn somewhere along the column length in addition to the two end-product streams. 如果进料从塔壳的某一个点引入这个塔被分成一个向上部分这个部分通常叫做精馏段还有一个向下的部分这个部分叫做提馏段。这些术语在多口进料塔中变得相当不确定。侧线产品沿着塔的某个地方被取中的塔会有两个最终产品馏分。

Equilibrium-Stage Concept Energy and mass—transfer processes in an actual distillation column are much too complicated to be readily modeled in any

equilibrium—leaving an equilibrium stage are in complete equilibrium with each other and thermodynamic relations can be used to determine the temperature of and relate the concentrations in the equilibrium streams at a given pressure. A hypothetical column composed of equilibrium stages (instead of actual contact trays)is designed to

number of hypothetical equilibrium stages required IS then converted to a number of actual trays by means of tray

an actual contact tray duplicates the performance of an equilibrium stage 平衡级的概念 实际的蒸馏塔中的能量以及质量传递过程太复杂以至于不能从一种方式直接做成模型。这个难题可以通过平衡级模型避免。在平衡级模式中气相和液相达到一个完全的平衡并且热力学关系可以被用于测量温度以及相关的浓度在某个特定压力下的平衡流中。由平衡级组成的一个特定的塔。代替了实际过程中的接触塔盘被设计用来完成实际塔的特定的分离。需要的假想得平衡级的数目通过塔盘效率的方法转化成一个实际塔盘的数目。塔盘效率描述了实际的接触塔盘的行为复制平衡级行为的程度。 Use of the equilibrium-stage concept separates the design of a

and methods needed to predict equilibrium—phase compositions r the separation that will be the column diameter is determined www.docin.com. 平衡级概念的使用 将蒸馏塔的设计分为三个主要的步骤热力学数据和方法被收集用来预测相平衡组分的。②需要完成一个指定的分离或者在一个给定平衡级数目的情况下平衡级的数目需要被计算。③平衡级的数被转化为等价的实际接触塔盘的数目或填料的高度。而且塔径被决定。 All separation operations require energy input in the form of heat or work. In the conventional distillation required to separate the species is added in the form of hear to the

column, where the temperature is lowest. This frequently results in a large energy-input requirement and low overall thermodynamic efficiency. With recent dramatic increases in energy costs, complex distillation operations that offer higher thermodynamic efficiency and lower energy-input requirements are being explored. 所有的分离操作需要以热量或者做功的形式的能量的输入。在传统的蒸馏操作中用来分离物质的能量被以热量与形式注入到塔底的再沸器中塔底的温度用最高的。热量从塔顶的冷凝器中被移走了在那里温度是最低的这就导致了大量的能量的输入以及低的热力学效率。随着最高近能耗上的显著增加能够有更高的热力学效率以及较低能量输入的复杂的蒸馏技术正在被开发。 Related Separation Operations The simple and complex distillation operations just described all have two things in common :(i) both rectifying and stripping sections are provided so