化工专业英语——单元操作.doc

单元操作Unit operation单元操作是化学工业和其他过程工业中进行的物料粉碎、输送、加热、冷却、混合和分离等一系列使物料发生预期的物理变化的基本操作的总称。对这些操作的研究，是化学工程的一个重要分支。各种单元操作依据不同的物理化学原理，应用相应的设备，达到各自的工艺目的。如蒸馏根据液体混合物中各组分挥发能力的差异，可以实现液体混合物中各组分分离或某组分提纯的目的。对单元操作的研究，以物理化学、传递过程和化工热力学为理论基础，着重研究实现各单元操作的过程和设备，故单元操作又称为化工过程及设备。单元操作的应用遍及化工、冶金、能源、食品、轻工、核能和环境保护等部门，对这些部门生产的大型化和现代化起着重要作用。Unit operation is a general term for a series of material handling, transportation, heating, cooling, mixing and separation of materials in the chemical industry and other process industries. The study of these operations is an important branch of chemical engineering. Various unit operations according to different physical and chemical principles, the application of the corresponding equipment, to achieve the purpose of their respective processes. Such as distillation according to the difference of the volatile capacity of the liquid mixture, can achieve the purpose of separation of components in liquid mixture or a group of purification. Based on the theory of physical chemistry, transfer process and chemical thermodynamics, the research on the operation of the unit has focused on the process and equipment of realizing the operation of each unit, so the unit operation is also called the chemical process and equipment. Application of unit operation in chemical industry, metallurgy, energy, food, light industry, nuclear energy and environmental protection departments, the production of these departments and the modernization of large-scale play an important role.单元操作沿革Unit operation evolution单元操作在化学工业的发展过程中，人们最初以具体产品为对象，分别进行各种产品的生产过程和设备的研究。随着化工生产的发展,人们逐渐认识到,各种不同产品的生产过程是由为数不多的基本操作和各种化学反应过程所组成的。在19世纪末英国学者G.E.戴维斯便提出了这种观点，但当时未引起足够重视。1915年美国学者A.D.利特尔首先提出单元操作这一概念,明确指出：“任何化工生产过程不论规模如何，皆可分解为一系列名为单元操作的过程，例如粉碎、混合、加热、吸收、冷凝、浸取、沉降、结晶、过滤等。” 1923年W.H.华克尔，W.K.刘易斯和W.H.麦克亚当斯等合著的化工原理一书出版，成为第一本全面阐述单元操作的著作。从此单元操作得到了广泛重视，成为化学工程中的奠基学科，常称为化工原理。Unit operation in the chemical industry development process, people first to specific products as the object, respectively, a variety of products, the production process and equipment. With the development of chemical industry, people come to realize that the production process of various kinds of products is composed of a few basic operations and a variety of chemical reactions. At the end of the nineteenth Century British scholar G.E. Davies put forward this view, but did not cause enough attention. In 1915, American scholar A.D. Littell first proposed the concept of unit operation, clearly pointed out: any chemical production process regardless of size, can be decomposed into a series of unit operation process, such as crushing, mixing, heating, condensation, absorption, extraction, crystallization, filtration, sedimentation. 1923 W.H. Hua Kerr, W.K. Lewis and W.H. Mcadams, CO authored the chemical principles, a book published, became the first comprehensive exposition of the work of the unit operation. Since the unit operation has been widely valued and become the foundation of chemical engineering disciplines, often referred to as the principle of chemical engineering.单元操作分类Unit operation classification随着化工生产的发展，单元操作的研究和开发相当活跃，新的单元操作不断形成。现在化工生产中常用的单元操作已达二十余种（见表）。单元操作按照所依据的基本原理分为：流体动力过程。这是一类以动量传递为主要理论基础的单元操作，有流体输送、沉降、过滤、混合等。传热过程。这是一类以热量传递为主要理论基础的单元操作，有换热、蒸发等。传质分离过程。这是一类以质量传递为主要理论基础的单元操作，用于各种均相混合物的分离，有蒸馏、吸收、萃取等。热质传递过程。这是一类由热量传递和质量传递两种规律共同决定的单元操作。这种过程与传热过程或传质分离过程不同，它的速率计算更加复杂，过程的极限也不再是热平衡和相平衡。此过程包括增湿、减湿、干燥、结晶等单元操作。热力过程。这是一类以热力学为主要理论基础的单元操作，如制冷。粉体工程。这是与固体颗粒加工、运动等有关的操作，有粉碎、流态化、颗粒分级等。With the development of chemical industry, the research and development of unit operation is quite active. Now commonly used in chemical production unit operation has reached more than twenty (see table). According to the basic principle, the unit operation is divided into: 1. This is a kind of unit operation based on the momentum transfer as the main theoretical basis. It has the fluid transportation, sedimentation, filtration, mixing and so on. Heat transfer process. This is a class of heat transfer as the main theoretical basis of the unit operation, there is heat exchange, evaporation, etc. Mass transfer separation process. It is a kind of unit operation, which is based on the mass transfer as the main theoretical basis. It is used for the separation of homogeneous mixtures, such as distillation, absorption, extraction and so on. The heat and mass transfer process. This is a class by the heat transfer and mass transfer of the two kinds of law together determine the operation of the unit. This process is different from the process of heat transfer and mass transfer, its rate calculation is more complicated, and the limit of the process is no longer thermal equilibrium and phase equilibrium. This process includes the increase of humidity, humidity, drying, crystallization and other elements of the operation. The thermodynamic process. This is a kind of unit operation based on thermodynamics as the main theoretical basis, such as. The powder engineering. This is related to the operation of solid particles, movement, etc., there are crushing, fluidization, particle classification, etc.单元操作发展Unit operation development随着化学工业的发展，单元操作一直处在不断的发展之中，其中最活跃的领域是混合物的分离。近年来单元操作的研究开发所取得的主要成果有以下几方面:新的分离技术不断得到开发和应用,如膜分离、区域熔炼、电磁分离、泡沫分离、超临界流体萃取和超离心分离等。在原有分离技术方面，处理能力加大、效率提高的新型设备不断出现；设备的放大效应逐步得到解决；研究成功许多合理利用能量的操作流程；一些高效的吸收剂、萃取剂等不断出现并在生产中应用。计算机模拟和辅助设计不断取得成果，缩短了新过程的开发周期；使设备的设计和操作更趋合理，从而提高了产品质量，降低了能量消耗。生产的发展对于单元操作不断提出新的课题。这些新课题的解决既促进了化工生产的发展，又推动了单元操作学科的发展。With the development of chemical industry, unit operation has been in constant development, among which the most active field is the separation of the mixture. The main achievements obtained in the research on the development of unit operations in recent years are the following: the new separation technology has been developed and applied, such as membrane separation, zone melting, electromagnetic separation, foam separation, supercritical fluid extraction and ultra centrifugation etc. The original separation technology, new equipment, improve the efficiency of processing capacity increased constantly; amplifica