The chemical industry today is a very diverse sector of manufacturing industry, within which it plays a central role.It makes thousands of different chemicals which the general public only usually encounter as end or consumer products.These products are purchased because they have the required properties which make them suitable for some particular application, e.g.a non-stick coating for pans or a weedkiller.Thus chemicals are ultimately sold for the effects that they produce.今天的化学工业已经是制造业中有着许多分支的部门，并且在制造业中起着核心的作用。它生产了数千种不同的化学产品，而人们通常只接触到终端产品或消费品。这些产品被购买是因为他们具有某些性质适合（人们）的一些特别的用途，例如，用于盆的不粘涂层或一种杀虫剂。这些化学产品归根到底是由于它们能产生的作用而被购买的。
The Need for Chemical Industry The chemical industry is concerned with converting raw materials, such as crude oil, firstly into chemical intermediates and then into a tremendous variety of other chemicals.These are then used to produce consumer products, which make our lives more comfortable or, in some cases such as pharmaceutical produces, help to maintain our well-being or even life itself.At each stage of these operations value is added to the produce and provided this added exceeds the raw material plus proceing costs then a profit will be made on the operation.It is the aim of chemical industry to achieve this. 对化学工业的需要
化学工业涉及到原材料的转化，如石油 首先转化为化学中间体，然后转化为数量众多的其它化学产品。这些产品再被用来生产消费品，这些消费品可以使我们的生活更为舒适或者作药物维持人类的健康或生命。在生产过程的每一个阶段，都有价值加到产品上面，只要这些附加的价值超过原材料和加工成本之和，这个加工就产生了利润。而这正是化学工业要达到的目的。
Individual manufacturing plants have capacities ranging from just a few tones per year in the fine chemicals area to the real giants in the fertilizer and petrochemical sectors which range up to 500,000 tonnes.The latter requires enormous capital investment, since a single plant of this size can now cost $520 million! This, coupled with the widespread use of automatic control equipment, helps to explain why the chemical industry is capital-rather than labor-intensive.一个制造厂的生产量很不一样，精细化工领域每年只有几吨，而巨型企业如化肥厂和石油化工厂有可能高达500,000吨。后者需要巨大的资金投入，因为一个这样规模的工厂要花费2亿5千万美元，再加上自动控制设备的普遍应用，就不难解释为什么化工厂是资金密集型企业而不是劳动力密集型企业。
The major chemical companies are truly multinational and operate their sales and marketing activities in most of the countries of the world, and they also have manufacturing units in a number of countries.This international outlook for operations, or globalization, is a growing trend within the chemical industry, with companies expanding their
1 activities either by erecting manufacturing units in other countries or by taking over companies which are already operating there.大部分化学公司是真正的跨国公司，他们在世界上的许多国家进行销售和开发市场，他们在许多国家都有制造厂。这种国际间的合作理念，或全球一体化，是化学工业中发展的趋势。大公司通过在别的国家建造制造厂或者是收购已有的工厂进行扩张。
The course, which revolved around the type of plant involved in large-scale industrial operations such as drying, crashing, distillation, fermentation, evaporation and crystallization, slowly became recognized as a model for courses elsewhere, not only in Britain, but overseas.The first fully fledged course in chemical engineering in Britain was not introduced until 1909;though in America, Lewis Norton (1855-1893) of MIT pioneered a Davis-type course as early as 1888.这们课程包括了大规模工业化操作的工厂的各种类型，如干燥、破碎、蒸馏、发酵、蒸发和结晶。后来逐渐在别的地方而不仅仅在英国，而是国外，成为许多课程的雏形。英国直到1909年化学工程学才成为一门较为完善的课程，而在美国，MIT的Lewis Norton早在1888年就已率先开出了Davis型课程。
The first law of thermodynamics is simply a statement of the conservation of energy.The sum of all the energy leaving a proce must equal the sum of all the energy entering, in the steady state.The laws of conservation of ma and energy are followed implicitly by engineers designing and operating procees of all kinds.Unfortunately, taken by itself, the first law has led to much confusion when attempting to evaluate proce efficiency.People talk of energy conservation being an important effort, but in fact, no effort is required to conserve energy－it is naturally conserved.The conclusions which can be drawn from the first law are limited because it does not distinguish among the various energy forms.Shaft work introduced by a reflux pump will leave a column as heat to the condenser just as readily as will heat introduced at the reboiler.Some engineers have fallen into the trap of lumping all forms of energy together in attempting to determine proce efficiency.This is obvious not justified－the various energy forms have different costs.
热力学第一定律是能量守恒的简单的一种描述。如图 3-1 所示，稳态时离开
一个过程的所有能量的总和必须与所进入该过程的能量总和相等。 工程师在设计和操作各种过程时绝对遵循质量和能量守恒定律。所不幸的是，就其本身而言，当试图评估过程的效率时，第一定律引起混淆不清。人们将能量守恒视为一种重要的努力成果， 但是事实上， 使能量守恒不需要花任何努力— — 能量本身就是守恒的。
因为第一定律没有区分各种各样能量的形式， 所以从第一定律所得到的结论是有限的。 由往复泵引入的轴功会以热量流向冷凝器的形式离开蒸馏塔， 与在再沸器引入的热一样容易。 在试图确定过程的效率时， 一些工程师总掉入
2 将各种形式的能量一起处理的陷阱。 这种做法明显是不合理，因为各种能量形式有着不同的费用。
Packed bed Reactor There are two basic types of packed-bed reactor: those in which the solid is a reactant, and those in which the solid is a catalyst.Many examples of the first type can be found in the extractive metallurgical金属提取 industries.In the chemical proce industries the designer will normally be concerned with the second type: catalytic reactors.Industrial packed-bed catalytic reactors range in size from small tubes, a few centimeters厘米 diameter to large diameter packed beds.Packed-bed reactors are used for gas and gas-liquid reactions.Heat-transfer rates in large diameter packed beds are poor and where high heat-transfer rates are required fluidized beds should be considered.填料床反应器
有两种类型的填料床反应器：一类以固体是反应物，另一类以固体是催化剂。在萃取湿法冶金工业中，可找到第一类反应器许多例子。
化学过程工业的设计者，通常关注的是第二类反应器：催化反应器。工业上的填料床催化反应器尺寸范围：小到直径为厘米长小试管，大到直径很大的填料床。填料床反应器用于气体和气－液两相反应。在直径很大的填料床上传热速率慢， 需要很大的传热速率的场所，应该考虑流化床反应器。
The first application is suggested by the name thermodynamics, which implies heat in motion.Most of these calculations can be made by the direct implementation of the first and second laws.Examples are calculating the work of compreing a gas, performing an energy balance on an entire proce or a proce unit, determining the minimum work of separating a mixture of ethanol and water, or evaluating the efficiency of an ammonia synthesis plant.第一种应用由热力学这个名词可联想到，热力学表示运动中的热。直接利用第一和第二定
律可完成许多（热效应和功效应的）计算。例如：计算压缩气体的功，对一个完整过程或某一过程单元的进行能量衡算，确定分离乙醇和水混合物所需的最小功，或者（evaluate）评估一个氨合成工厂的效率。
Fluidized bed Reactor流化床反应器
A fluidized bed reactor (FBR) is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions.In this type of reactor, a fluid (gas or liquid) is paed through a granular粒状的 solid material (usually a catalyst poibly shaped as tiny spheres) at high enough velocities to suspend悬浮 the solid and cause it to behave as though it were a fluid.This proce, known as fluidization, imparts many important advantages to the FBR.As a result, the fluidized bed reactor is now used in many industrial applications.流化床反应器
3 流化床反应器（FBR）是一种用于多相化学反应的反应器。在这种反应器中，流体（气体或液体）是通过一个粒状固体物料在足够高的速度（通常一种催化剂形成的微小球体）从而使固体悬浮并导致其行为就像它是一种流体。这一过程，称为流化，它在流化反应器中起了重要作用。因此，流化床反应器现在用于许多工业应用。
Basic principles The solid substrate (the catalytic material upon which chemical species react) material in the fluidized bed reactor is typically supported by a porous渗透的 plate, known as a distributor分散器.The fluid is then forced through the distributor up through the solid material.At lower fluid velocities, the solids remain in place as the fluid paes through the voids 空隙in the material.This is known as a packed bed reactor填充床反应器.As the fluid velocity is increased, the reactor will reach a stage where the force of the fluid on the solids is enough to balance the weight of the solid material.This stage is known as incipient fluidization初始流态化 and occurs at this minimum fluidization velocity最小流化速度.Once this minimum velocity is surpaed, the contents of the reactor bed begin to expand and swirl around much like an agitated tank搅拌器 or boiling pot of water.The reactor is now a fluidized bed.Depending on the operating conditions and properties of solid phase various flow regimes流动状态 can be observed in this reactor. 基本原则
固体基质（化学物质发生反应依赖的催化材料）在流化床反应器中常被一个多孔板支撑，它就是分配器。然后用流体力透过分散器流过固体材料。在较低的流速下，固体颗粒被保留在流体通过在材料的空隙中。这就是所谓的填充床反应器。随着流速的增加，反应器将达到一个阶段，流体的对固体材料的力足以平衡固体材料的重量。这一阶段被称为初始流态化，这个就是最小流化速度。一旦超过这个最低速度，对反应器床层中的物质开始膨胀，像一个搅拌槽或煮沸一壶水形成的漩涡。该反应器就是流化床。在操作条件及不同固相的各种流态性质情况下，可以观察到这个反应器。
While dealing with procees in which systems exchange matter or energy, claical thermodynamics is not concerned with the rate at which such procees take place, termed kinetics.For this reason, the use of the term “thermodynamics” usually refers to equilibrium thermodynamics.In this connection, a central concept in thermodynamics is that of quasistatic procees, which are idealized, “infinitely slow” procees.Time-dependent thermodynamic procees are studied by non-equilibrium thermodynamics.虽然在这系统交换物质或能量，古典热力学不与速率等过程发生，有关程序处理称为动力学。由于这个原因，对“热力学“的使用通常是指平衡态热力学。在这方面，在热力学的核心概念是，准静态过程，这是理想化的，“无限慢“的
4 进程。随时间变化的热力学过程，研究了非平衡热力学。
Second law of Thermodynamics Entropy plays a critical role in thermodynamic analysis, because it is the miing factor that we were seeking to allow us to predict the direction of change in atomic or molecular systems.The eential result constitutes the second law of thermodynamics, which can be stated in several ways, not all of them obviously equivalent, but in fact all of them providing the same meage.Here are some of them: 1.Heat does not spontaneously flow from a cold body to a hot body.2.Spontaneous procees are not thermodynamically reversible.3.The complete conversion of heat into work is impoible without leaving some effect elsewhere.4.It is impoible to convert heat into work by means of a constant temperature cycle.5.All natural procees are accompanied by a net gain in entropy of the system and its surroundings.This last statement is most useful to us.Let us write 热力学第二定律
热力学熵中起着关键作用的分析，因为它是缺少的因素，我们正在寻求让我们来预测在原子或分子系统改变方向。结果构成的基本热力学，可从几个方面说明，不是所有的人都明显相当于第二定律，但实际上他们都提供相同的消息。 下面是其中一些：
1.热量不会自发地从寒冷的身体流动到热的身体。 2.热力学自发过程不可逆的。
3.热能转化为工作的转换是不可能完全不留一些影响其他地方。 4.这是不可能转化为工作的恒温循环热。
5.所有的自然过程都伴随着一个在系统和它的周围熵净收益。 这最后的陈述是对我们最有用的。
a.Closed System is a system that is closed with respect to the flow of matter, e.g., fixed, closed volume.A closed system is defined by a fixed quantity of ma.b.Open System is a system that is open with respect to the flow of matter such as a compreor.The system is defined by an imaginary volume surrounding the region of interest.The surface of this volume is called the control or sigma (s ) surface.Ma, heat, work and momentum can flow acro the control surface.有道：答:封闭系统是一个系统,关闭时对物质的流动,如。、固定收卷。一个封闭的系统被定义为固定数量的质量。
b。开放系统是一个开放的系统对压缩机等物质的流动。周围的系统被定义为一个虚构的体积感兴趣的地区。本卷的表面被称为控制或西格玛(s)表面。质量、热量、工作和动量可以在控制表面流动。
搜狐：封闭系统是封闭相对于物质的流动，例如，固定的，封闭的体积的系统。一个封闭的系统质量的一个固定的量来定义。
5 开放系统是一种系统，它是相对于物质的流动，例如一个压缩机开启。该系统是由周围的感兴趣区域的假想体积限定。这个体积的表面被称为控制或西格玛（次）的表面上。质量，热量，工作和动量可以通过控制表面流动。
Fluid flow 流体流动 Heat transfer传热 Evaporation 蒸发 Crystallization 结晶 Drying 干燥 Distillation 蒸馏 Absorption 吸收 Adsoption 吸附 Extraction 萃取 Leaching 浸取 Membrane separation 膜分离 Mechanical physic separation 机械物理分离
