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1、Lesson 4 Chemical Reaction Engineering化学反应工程 A1 Every industrial chemical process is designed to produce economically a desired product from a variety of starting materials through a succession of treatment steps. 每一个工业化学过程的目的是从不同的原材料，经过一系列的处理步骤生产经济所需的产品。2 Fig. 4-1 shows a typical situation. 图 4-1展示
2、了一个典型的情况。3 The raw materials undergo a number of physical treatment steps to put them in the form in which they can be reacted chemically. 原料进行了一些物理处理的步骤，使它们能够发生化学反应。4 They then pass through the reactor.然后让他们通过反应器。5 The products of the reaction must then undergo further physical treatment- -separati
3、ons, purifications, etc. - for the final desired product to be obtained.产物要经历进一步的物理处理分离，净化提纯等等，以获得期望的最终产品。 B1 Design of equipment for the physical treatment steps is studied in the unit operations. 物理处理步骤设备的设计在单元操作中研究。2 Here we are concerned with the chemical treatment step of a process. 在这里我们关心的是一个
4、过程的化学处理步骤。3 Economically this may be in inconsequential unit, say a simple mixing tank .从经济的角度说，这可能是个不重要的单元，比如说一个简单的搅拌槽。4 More often than not, however, the chemical treatment step is the heart of the process, the thing that makes or breaks the process economical. 然而通常，化学处理步骤是一个过程的核心，它决定这个过程经济的成败。 C1
5、 Design of the reactor is no routine matter, and many alternatives can be proposed for a process .反应器的设计不是普通的事，对于一个过程有许多可供选择的建议。2 In searching for the optimum it is not just the cost of reactor that must be minimized. 寻找最佳的条件，不仅是反应器成本的最小化。3 One design may have low reactor cost, but the materials lea
6、ving the unit may be such that their treatment requires much higher cost than alternative designs. 一个设计可能反应器的成本较低，但材料离开装置可能比其他的设计需要更高的处理费。4 Hence, the economics of the over-all process must be considered.因此，必须要考虑整个过程的经济。 D1 Reactor design uses information, knowledge, and experience from a variety of
7、 areas thermodynamics, chemical kinetics, fluid mechanics, heat transfer, mass transfer, and economic.反应器的设计使用了各个领域的信息，知识和经验，比如热力学，化学动力学，流体力学，传热，传质，和经济学。2 Chemical reaction engineering is, the synthesis of all these factors with the aim of properly designing a chemical reactor. 化学反应工程，是这些因素的综合学科，旨在设
8、计出正确的化学反应器。 E1 The design of chemical reactors is probably the one activity which is unique to chemical engineering, and it is probably this function more than anything else which justifies the existence of chemical engineering as a distinct branch of engineering.化学反应器的设计对于化学工程而言可能是一个独特的活动，它的这个功能可能比
9、任何东西都更能证明化学工程作为一个独特的分支工程的存在。 F1 In chemical reactor design there are two questions which must be answered: (i) What change can we expect to occur？ (ii)How fast will they take place？化学反应器的设计有两个必须回答的问题： （1）我们预期发生什么变化？（2）他们发生的有多快？2 The first question concerns thermodynamics, the second the various rate
10、 processes- -chemical kinetics, heat transfer, etc.第一个问题涉及热力学，第二个问题涉及各种速率过程化学动力学，传热等。3 Putting these all together and trying to determine how these processes are interrelated can be an extremely difficult problem; hence we start with the simplest of situations and build up our analysis by considerin
11、g additional factors until we arc able to handle the more difficult problems.把这些放在一起，试图确定这些过程是怎样相关联的， 是一个非常困难的问题；因此，我们从最简单的情况着手，考虑附加因素，建立我们的分析，直到我们能处理更难的问题。 G Thermodynamics 热力学1 Thermodynamics gives two important pieces of information needed in design, the heat liberated or absorbed during reaction
12、 and the maximum possible extent of reaction. 热力学给出设计中需要的两条重要的信息，在反应中会放出和吸收热量，而且最大值可能表示反应的程度。2 Chemical reactions are invariably accompanied by the liberation or absorption of heat, the magnitude of which must be known for proper design. Consider the reaction aArR+sS ,Hrpositive, endothermic ; negat
13、ive , exothermic 化学反应总是伴随着热量的释放或吸收，为了合理的设计，必须知道它的大小，考虑下面的反应：aArR+sS ,Hr ,正反应，吸热；逆反应，放热。 H1 The heat of reaction at temperature T is the heat transferred from surroundings to the reacting system when a moles of A disappear to form r moles of R and s moles of S, with the system measured at the same te
14、mperature and pressure before and after reaction. 温度为T时， a mol的A消失生成了r mol的R和s mol的S，反应的热量是环境传递给反应体系的，这是在反应前后相同的温度和压力下对体系测量的结果。2 With heats of reaction known or estimable from thermochemical data, the magnitude of the heat effects during reaction can be calculated. 从热化学数据中可以得到或估算反应的热量，反应中产生的热量大小可以计算
15、。I1 Thermodynamics also allows calculation of the equilibrium constant K from the standard free energies of the reacting materials. 热力学也可以从反应物的标准自由能来计算平衡常数。2 With the equilibrium constant known, the expected maximum attainable yield of the products of reaction can be estimated. 由于平衡常数已知，可以估算出反应中可以得到
16、的预期产品的最大产量。 J Chemical Kinetics 化学动力学1 Under appropriate conditions feed materials may be transformed into new and different materials which constitute different chemical species. 适当的条件下，供给的材料可能转变为新的不同的材料，形成不同的化学物质。2 If this occurs only by rearrangement or redistribution of the constituent atoms to form new mol
