The Anatomy of a Chemical Manufacturing Process 化工生产过程构成
    The basic components of a typical chemical process(n过程;步骤;方法;工艺,vt 加工;处理) are shown in Fig.1, in which each block represents a stage in the overall process for producing a product from the raw materials. Fig.1 represents a generalized(无显著特点的,一般的) process; not all the stages(步骤;阶段) will be needed for any particular(特定的) process and the complexity of each stage will depend on the nature of the process. Chemical engineering design is concerned with the selection and arrangement（排列；安排）of the stages, and the selection, specification and design of the equipment required to perform(演出；执行；完成任务) the stage functions.
    典型的化学工艺的基本构成示于图1., 在此图中，每一个方框表示从原料到加工成产品的全过程中的一个步骤。图1所示只是一般的情况，对于一个特定的工艺来说并非所有的步骤都是必需的，而且每一个步骤的复杂程度取决于生产过程的性质。化工设计所关注的是各步骤的选择与安排，以及完成各步骤的任务所需设备的选择、说明和设计。
    Stage 1.Raw material storage-原始原料贮备
    Unless the raw materials (also called essential materials, or feedstocks) are supplied as intermediate products (intermediates) from a neighboring plant, some provision（供应） will have to be made to hold(保持；把握；拥有；占据) several days, or weeks storage to smooth out fluctuations（波动） and interruptions（中断） in supply. Even when the materials come from an adjacent （邻近的） plant, some provision is usually made to hold a few hours, or even a few days, supply to decouple（断开；中断）the processes. The storage required will depend on the nature of the raw materials, the method of delivery（递送，发送，交货）, and what assurance can be placed on the continuity of supply. If materials are delivered by ship (tanker or bulk carrier), several weeks stocks may be necessary; whereas（反之；然而；但是） if they are received by road or rail, in smaller lots(份额；一堆), less storage will be needed.
    除非有邻近的工厂提供他们的半成品作为原料，某些原料的贮存必须形成几天或者数周的贮量以备供应的波动和中断。即使有原料由邻近的工厂提供，有些供应常需保持几个小时甚至几天的备用，以防供应断绝。原料必需的贮备量取决于原料的性质、输送方式和连续供应的保障程度。如果原料由大型散装货船运送，几周的贮备也许是必要的，反之如果原料由公
路或者铁路分小批量多批次运输，则可较少贮备。
    Stage 2. Feed preparation-进料预处理
    Some purification, and preparation, of file raw materials will usually be necessary before they are sufficiently（足够地；充分地） pure, or in the right form, to be fed（应为feed）to the reaction satge. For example, acetylene generated by the carbide（碳化物；碳化钙；电石） process contains arsenical (砷的) and sulphur compounds, and other impurities, which must be removed by scrubbing （擦洗，使[气体]净化）with concentrated sulphuric acid (or other processes) before it is sufficiently pure for reaction with hydrochloric acid (此处有误，应为hydrochloride氯化氢) to produce dichloroethane. Liquid feeds will need to be vaporized before being fed to gas-phase reactors, and solids may need crushing（破碎）, grinding（研磨） and screening（筛分）.
    将原料经足够的纯化以适当的形式送到反应步骤之前，某些净化和预处理是必须的。例如，由碳化钙发生的乙炔气含有砷和硫的化合物以及其他的杂质，必须在乙炔有足够的纯度与氯化氢反应制造二氯乙烷之前，用浓硫酸洗去（或者其他的处理过程）这些杂质。液态物
reaction英语
料在进入气相反应器前要蒸发汽化，固体物料需要破碎、研磨和筛分。
    Stage 3. Reactor 反应器
    The reaction stage is the heart of a chemical manufacturing process. In the reactor the raw materials are brought together under conditions that promote （促进；助长） the production of the desired product; invariably, by-products and unwanted compounds (impurities) will also be formed.
    反应步骤是化学加工过程的心脏。在反应器中，各种原料在有利于生成期望产物（目的产物）的条件下汇合，总的来说，副产物和不期望的物质也会生成。
    Stage 4. Product separation 产品分离
    In this first stage alter（应为after） the reactor, the products and by-products are separated from any unreacted material. If in sufficient quantity, the unreacted material will be returned directly to the reactor or to the feed purification and preparation stage. The by-products may also be separated from the products at this stage.
    在反应之后的第一个分离步骤中，将目的产物和副产物与未反应的原料分离。如果未反应的物料足够多，则可以直接返回到反应器或者返回到原料的净化与预处理。在这个步骤中，产物与副产物也可被分离。
    Stage 5. Purification 净化（或者称精制）
    Before sale the main product will usually need purification to meet the product specification. If produced in economic quantities, the by-products may also be purified for sale.
    在主产品销售之前常需要精制以符合产品规格。如果副产品有经济上的产出量，也可以精制后销售。
    Stage 6. Product storage 产品贮存
    Some inventory （目录，清单） of finished product （成品）must be held to match production with sale. Provision （规定） for product packaging and transport will also be needed, depending on the nature of the product. Liquids will normally be dispatched in dru
ms（鼓；桶） and in bulk （散装的） tankers (road, rail and sea), solids in sacks (袋子), cartons （硬纸箱）or bales（打包；捆扎）.
    产品目录必须与销售的产品相符。根据产品的性质，也需要规定包装和运输方式。液体产品通常用桶和槽罐分装，固体物料则装入袋中、纸箱中或者打成大包装。

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