修改过程装备与控制工程专业英语翻译
过程装备与控制工程专业英语翻译
过程装备与控制工程专业英语翻译第一篇：过程装备与控制工程专业英语翻译1、In our comparison of the net electrical power output of both combined heat and power(CHP)and power-only plants, the electrical output of the CHP plants is assumed to be the output that could the oretically be produced if there were no heat electrical power净电力combined heat and power热电联供Plant设备be assumed to be假设为Theoretically理论地；理论上在我们的热电联供和只供电的设备的净电力输出比较中，热电联供设备的电力输出是看做理论上如果没有热输出时产生的输出量。
2、The lower heating value is defined here as the higher heating value(HHV)minus the energy necessary to evaporate the water that is created by the combustion of the hydrogen in the fuel and minus the energy needed to evaporate the moisture that was already part of the fuel before combustion.heating value热值Evaporate [ɪ'væpəret]vt.使……蒸发；使……脱水；使……消失vi.蒸发，挥发；消失，失踪Combustion [kəm'bʌstʃən] n.燃烧，氧化；骚动moisture ['mɒɪstʃə] n.水分；湿度；潮湿；降雨量低热值在这里定义为高热值减去使水分蒸发所需要的能量，这些能量包括使燃料中的氢燃烧产生的水分蒸发所必需的能量和使燃料燃烧前所含有的水分蒸发所需要的能量。
过程装备与控制工程专业英语翻译 19
Reading Material 19Shell-and-Tube Heat ExchangersShell-and-tube exchangers are made up of a number of tubes in parallel and series through which one fluid travels and enclosed in a shell through which the other fluid is conducted. The shell side is provided with a number of baffles to promote high velocities and largely more efficient cross flow on the outsides of the tubes. The versatility and widespread use of this equipment has given rise to the development of industrywide standards of shich the most widely observed are the TEMA standards. A typical shell-and-tube exchanger is presented on Fig. 4. 3.Baffle pitch , or distance between baffles, normally is 0. 2~1. 0 times the inside diameter of the shell. Both the heat transfer coefficient and the pressure drop depend on the baffle pitch, so that is selection is part of the optimization of the heat exchanger. The window of segmental baffles commonly is abort 25%, but it also is a parameter in the thermal-hydraulic design of the equipment.In order to simplify external piping, exchangers mostly are built with even number of tube passes. Partitioning reduces the number of the tubes that can be accommodated in a shell of a given size. Square tube pitch in comparison with triangular pitch accommodates fewer tubes but is preferable when the shell side must be cleaned by brushing.Two shell passes are obtained with a longitudinal baffle. More than two shell passes normally are not provided in a single shell, brt a 4~8 arrangement is thermally equivalent to two 2~4 shells in series, and higher combinations is obtainable with shell-and –tube exchangers, in particular:●Single phase, condensation or boiling can be accommodated in either the tubes or the shell, in vertical or horizontal positions.● Pressure range and pressure drop are virtually unlimited, and can be adjusted independently for the two fluids.●Thermal stresses can be accommodated inexpensively.● A great variety of materials of construction can be used and may be different for the shelland tubes.●Extended surfaces for improved heat transfer can be used on either side.● A great range of thermal capacities is obtainable.●The equipment is readily dismantled for cleaning or repair.Several considerations may influence which fluid goes on the tube side or the shell side.The tube side is preferable for the fluid that has the higher pressure, or the higher temperature or is more corrosive. The tube side is less likely to leak expensive or hazardous fluids and is more easily cleaned. Both pressure drop and laminar heat transfer can be predicted more accurately for the tube side. Accordingly, when these factors are critical, the tube side should be selected for that fluid.Turbulent flow is obtained at lower Reynolds numbers on the shell side, so that the fluid with the lower mass flow preferably goes on that side. High Reynolds numbers are obtained by multipassing the tube side, but at a price.A substantial number of parameters is involved in the design of a shell-and –tube heatexchanger for specified thermal and hydraulic conditions and desired economics, including: tube diameter, thickness, length, number of passes, pitch, square or triangular; size of shell,number of shell baffles, baffle type, baffle windows, baffle spacing, and so on. For even a modest sized design program, it is estimated that 40 separate logical designs may need to be made which lead to ????????? different paths through the logic. Since such a number is entirely too large for normal computer process, the problem must be simplified with some arbitrary decisions based on as much current practice as possible.阅读材料19管壳式换热器管壳式换热器是由一定数量的内有液体流动的平行管子和将其包围住的内有另一种液体的壳体组成的。
过程装备与控制工程英语
过程装备与控制工程英语1.过程装备(Process equipment)The process equipment in the factory is responsible for manufacturing products efficiently.2.控制工程(Control engineering)Control engineering plays a crucial role in ensuring the stability and reliability of industrial processes.3.设备(Equipment)The factory invested in state-of-the-art equipment to improve production efficiency.4.流程(Process)The production process includes multiple stages, each with its own specific requirements.5.控制(Control)The control system allows operators to monitor and adjust various parameters for optimal performance.6.自动化(Automation)Automation has greatly improved efficiency in manufacturing processes.7.传感器(Sensor)Sensors are used to collect real-time data and provide feedback for control purposes.8.测量(Measurement)Accurate measurement of process variables is crucial for maintaining quality standards.9.监控(Monitoring)Continuous monitoring of process parameters is essential for early detection of issues.10.仪表(Instrumentation)Instrumentation plays a vital role in collecting and displaying data from various sensors in a process.11.采样(Sampling)Regular sampling of raw materials ensures their quality meets the required standards.12.环境监测(Environmental monitoring)Efficient control engineering systems enable real-time environmental monitoring.13.压力(Pressure)The pressure in the system is carefully controlled to ensure stable operation.14.温度(Temperature)Temperature control is crucial for maintaining the desired chemical reaction rate.15.流量(Flow rate)Monitoring and controlling the flow rate of liquid or gas is important for process efficiency.16.液位(Liquid level)Accurate measurement of liquid level ensures proper functioning of the process.17.控制阀(Control valve)Control valves regulate the flow rate or pressure offluid in a process.18. PLC (Programmable Logic Controller)PLCs are widely used in control engineering to automate and monitor industrial processes.19.数据采集(Data acquisition)Data acquisition systems collect and record data from various sensors for analysis.20.仪器仪表校准(Instrument calibration)Regular instrument calibration ensures accurate measurement and control.21.故障诊断(Fault diagnosis)Advanced control engineering systems can detect and diagnose faults in real-time.22.实时控制(Real-time control)Real-time control engineering allows for immediate adjustments to process conditions.23.可靠性(Reliability)Reliability is a key factor in choosing process equipment and control systems.24.自适应控制(Adaptive control)Adaptive control algorithms constantly adjust process parameters to optimize performance.25.能源管理(Energy management)Efficient control engineering strategies can help optimize energy consumption in industrial processes.。
过程装备与控制工程专业专业英语翻译9
Reading Material 9Heat Treatment of SteelTypes of Heat Treating Operations Five operations are detailed in this lesson as the basis of heat treatment. Explanations of theseOperations follow.Stress Relieving When a metal Is heated， expansion occurs which is more or less proportional to the temperature rise. Upon cooling a metal,the reverse reaction takes place. That is, a contraction is observed．When a steel bar or plate is heated at one point more than at another，as in welding or during forging，Internal stresses are set up．During heating, expansion of the heated area cannot take place unhindered，and it tends to deform．On cooling，contraction is prevented from taking place by the unyielding cold metal surrounding the heated area．The forces attempting to contract the metal are not relieved，and when the metal is cold again，the forces remain as internal stresses．stresses also result from volume changes, which accompany metal transformations and precipitation．Internal or residual stresses are bad because they may cause warping of steel parts when they are machined．To relieve these stresses，steel is heated to around 5950C，assuming that the entire part is heated uniformly, then cooled slowly back to room temperature．This procedure is called stress relief annealing, or merely stress relieving.Because of characteristics inherent in cast steel, the normalizing treatment is more frequently applied to ingots prior to working， and to steel castings and forgings prior to hardening.Normalizing The process of normalizing consists of heating to a temperature above the third transformation temperature and allowing the part to cool in still air. The actual temperature required for this depends on the composition of the steel, but is usually around 8700C. Actually, the term normalize does not describe the purpose. The process might be more accurately described as a homogenizing or grain-refining treatment. Within any piece of steel, the composition is usually not uniform throughout. That is, one area may have more carbon than the area adjacent to it. These compositional differences affect the way in which the steel will respond to heat treatment. If it is heated to a high temperature, the carbon can readily diffuse throughout, and the result is a reasonably uniform composition from one area to the next. The steel is then more homogeneous and will respond to the heat treatment in a more uniform way.During cold deformation, steel has a tendency to harden in deformed areas, making it more difficult to bend and liable to breakage. Alternate deforming and annealing operations are performed on most manufactured steel products.Full annealing Full annealing, where steel is heated 50 to 100C above the third transformation temperature for hypoeutectoid steels, and above the lowest transformation temperature for hypereutectoid steels, and slow cooled, makes the steel much easier to cut, as well as bend. In full annealing, cooling must take place very slowly so that a coarse pearlite is formed. Slow cooling is not essential forprocess annealing, since any cooling rate from temperatures below the lowest transformation temperature will result in the same microstructure and hardness.Process annealing Process annealing consists of heating steel to a temperature just below the lowest transformation temperature for a short time. This makes the steel easier to form. This heat treatment is commonly applied in the sheet and wire industries, and the temperatures generally used are from 550 to 650C.Annealing The two--stage heat treating process of quenching and tempering is designed to produce high strength steel capable of resisting shock and deformation without breaking. On the other hand, the annealing process is intended to make steel easier to deform or machine. 1n manufacturing steel products, machining and severe bending operations are often employed. Even tempered steel may not cut or bend very easi1y and annealing is often necessary.The effect of tempering may be il1ustrated as follows. If the head of a hammer were quenched to a fully martensitic structure, it probably would crack after the first few blows. Tempering during manufacture of the hammer imparts shock resistance with only a slight decrease in hardness. Tempering is accomplished by heating a quenched part to some point below the transformation temperature, and holding it at this temperature for an hour or more, depending on its size. Most steels are tempered between 205°C and 595°C. As higher temperatures are employed, toughness or shock resistance of the steel is increased, but the hardness and strength decrease.Tempering Ductility is the ability of a metal to change shape before it breaks. Fleshly quenched martensite is hard but not ductile; in fact, it is very brittle. Tempering is needed to impart ductility to the martensite, usually at a small sacrifice in strength. In addition, tempering greatly increases the resistance of martensite to shock loading.Heat Treatment The hardest condition for any given steel is obtained by quenching to a fully martensitic structure. Since hardness is directly related to strength, a steel composed of 100% martensite is at its strongest possible condition. However, strength is not the only property that must be considered in the application of steel parts. Ductility may be equally important.Change or modify the magnetic properties of steel.Improve the electrical properties;Improve the machinability;Increase the toughness; that is, to produce a steel having both a high tensile strength and good ductility, enabling it to withstand high impact ;Increase the hardness so as to increase resistance to wear or to enable the steel to withstand more service conditions;Decrease the hardness and increase the ductility;Secure the proper grain structure ;Refine the grain structure of hot worked steels which may have developed coarse grain size ;Remove stresses induced by cold working or to remove stresses set up by nonuniform cooling of hot metal objects;Reasons for Heat Treating Heat treatment of steel is usually intended to accomplish any one of the following objectives:Stress relieving Stress relieving is the heating of steel to a temperature below the transformation temperature, as in tempering, but is done primarily to relieve internal stress and thus prevent distortion or cracking during machining. This is sometimes called process annealing.Tempering Tempering consists of reheating a quenched steel to a suitable temperature below the transformation temperature for an appropriate time and cooling back to room temperature. How this process makes steel tough will be discussed later.Hardening Hardening is carried out by quenching a steel, that is, cooling it rapidly from a temperature above the transformation temperature. Steel is quenched in water or brine for the most rapid cooling, in oil for some alloy steels, and in air for certain higher alloy steels. After steel is quenched, it is usually very hard and brittle; it may even crack if dropped. To make the steel more ductile, it must be tempered.Normalizing Normalizing is identical with annealing, except that the steel is air cooled; this is much faster than cooling in a furnace. Steel is normalized to refine grain size, make its structure more uniform, or to improve machinability. Full annealing Full annealing is the process of softening steel by a heating and cooling cycle, so that it may be bent or cut easily. In annealing, steel is heated above a transformation temperature and cooled very slowly after it has reached a suitable temperature. The distinguishing characteristics of full annealing are: (a) temperature above the critical temperature and (b) very slow cooling, usually in the furnace.阅读材料9钢的热处理各种不同的热处理操作本单元介绍了五种热处理的基本方法。
过程装备与控制工程专业英语翻译 20
Reading material 20Basic Stirred Tank DesignThe dimensions of the liquid content of a vessel and the dimensions and arrangement of impellers, baffles and other internals are factors that influence the amount of the energy required for achieving a needed amount of agitation or quality of mixing. The internal arrangements depend on the objectives of the operation: whether it is to maintain homogeneity of a reacting mixture or to keep a solid suspended or a gas dispersed or to enhance heat or mass transfer. A basic range of design factors, however, can be defined to cover the majority of the cases, for example as in Fig.4.4 (a).The Vessel A dished bottom requires less power than a flat one. When a single impeller is to be used, a liquid level equal to the diameter is optimum, with the impeller located at the center for an all-liquid system. Economic and manufacturing considerations, however, often dictate higher ratios of depth to diameter.Baffles Except at very high Reynolds numbers, baffles are needed to prevent vortexing and rotation of the liquid mass as a whole. When solids are present or when a heat transfer jacket is used, the baffles are offset from the wall a distance equal to one-sixth the baffle width which is about one-twelfth the tank diameter. Four radial baffles at equal spacing are standard; six are only slightly more effective, and three appreciably less so. When the mixer needed, particularly at low viscosity.Draft T ubes A draft tube is a cylindrical housing around and slightly larger in diameter than the impeller. Its height may be little more than the diameter of the impeller or it may extend the full depth of the liquid, depending on the flow pattern that is required. Usually draft tubes are used with axial impellers to direct suction and discharge streams. An impeller-draft tube system behaves as an axial flow pump of somewhat low efficiency. Its top to bottom circulation behavior is of particular valve in deep tanks for suspension of solids and for dispersion of gases.Impeller Size This depends on the kind of impeller and operating conditions described by the Roynolds, Froude, and Power numbers as well as individual characteristics whose effects have been correlated. For the popular turbine impeller, the ratio of diameters of impeller and vessel fallsin the range, d/0.30.6D , the lower values at high rpm, in gas dispersion, for example.tImpeller Speed With commercially available motors and speed reducers, standard speeds are 37, 45, 56, 68, 84, 100, 125, 155, 190, and 320 rpm. Power requirements usually are not great enough to justify the use of continuously adjustable steam turbine drives. Two-speed drives may be required when starting torques are high, as with a settled slurry.Impeller Location As a first approximation, the impeller can be placed at 1/6 the liquid level off the bottom. In some cases there is provision for changing the position of the impeller on the shaft. For off-bottom suspension of solids, an impeller location of 1/3 the impeller diameter off the bottom may be satisfactory.Kinds of Impellers A rotating impeller in a fluid imparts flow and shear to it, the shear resulting from the flow of one portion of the fluid past another. Limiting cases of flow are in the axial or radial directions so that impellers are classified conveniently according to which of these flows is dominant. By reason of reflections from vessel surfaces and obstruction by baffles and other internals, however, flow patterns in most cases are mixed.Because the performance of a particular shape of impeller usually cannot be predicted quantitatively, impeller design is largely an exercise of judgment so a considerable variety has been put forth by various manufacturers. A few common types are illustrated on Fig. 4. 4 (b) (i) and are described as follows:b. The three-bladed mixing propeller is modeled on the marine propeller but has a pitch selected for maximum turbulence. They are used at relatively high speeds (up to 1800 rpm ) with low viscosity fluids, up to about 4000 cP. The stabilizing ring shown in the illustration sometimes is included to minimize shaft flutter and vibration particularly at low liquid level.c. The turbine with flat vertical blades extending to the shaft is suited to the vast majority of mixing duties up to 100000 cP or so at high pumping capacity.d. The horizontal plate to which the impeller blades of this turbine are attached has a stabilizing effect. Backward curved blades may be used for the same reason as for typee.e. Turbine with blades are inclined 45 (usual,ly). Constructions with two to eight bladesarde used, six being most common. Combined axial and radial flow are achieved. Especially effective for heat exchange with vessel walls or internal coils.f. Curved blade turbines effectively disperse fibrous materials without fouling. The swept back blades have a lower starting torque than straight ones, which is important when starting up settled slurries.g. Shrouded turbines consisting of a rotor and a stator ensure a high degree of radial flow and shearing action, and are well adapted to emulsification and dispersion.h. Anchor paddles fit the contour of the container, prevent sticking of pasty materials, and promote good heat transfer with the wall.i.Gate paddles are used in wide, shallow tanks and for materials of high viscosity when lowshear is adequate. Shaft speeds are low.阅读材料20基本搅拌槽设计容器的液体容量、叶轮、挡板和其他内部构件的尺寸和安装是影响振动次数和搅拌质量的因素。
过程装备与控制工程专业专业英语翻译8
Reading material 8Examples of Manufacturing Processes (continued)The flame cutting process can only be used for easily combustible materials. For other materials, cutting processes based on the thermal basic process--melting--have been developed (arc cutting, arc plasma cutting, etc. ). This is the reason cutting is listed in the table, which is at the beginning of Unit 8, under both thermal and chemical basic processes.Flame Cutting Flame Cutting can be characterized as: mass reducing, solid state of work material, chemical primary basic process--combustion. .In flame cutting, the material (a ferrous metal) is heated to a temperature where combustion by the oxygen supply can start. Theoretically, the heat liberated should be sufficient to maintain the reaction once started, but because of heat losses to the atmosphere and the material, a certain amount of heat must be supplied continuously.A torch is designed to provide heat both for starting and maintaining the reaction. Most widely used is the oxyacetylene cutting torch, where heat is created by the combustion of acetylene and oxygen. Th. oxygen for cutting is normally supplied through a center hole in the tip of the torch.Electrochemical Machining Electrochemical Machining (ECM) can be characterized as: mass reducing, solid state of work material, chemical primary basic process-electrolytic dissolution. Electrolytic dissolution of the workpiece is established through an electric circuit, where the work material is made of the anode, and the tool, which is approximately the inverse shape of the desired geometry, is made of the cathode. The electrolytes normally used are water--based saline solutions (sodium chloride and sodium nitrate in l0%-30% solutions). The voltage, which usually is in the range 5-20 V, maintains high current densities, 0.5-2 A/mm2, giving a relatively high removal rate, 0.5-6 cm3/min, depending on the work material.Electrical Discharge Machining E lectrical Discharge Machining (EDM ) can be characterized as: mass reducing, solid state of work material, thermal primary basic process-melting and evaporation. In EDM, material is removed by the erosive action of numerous small electrical discharges (sparks ) between the work material and the tool (electrode), the latter having the inverse shape of the desired geometry. Each discharge occurs when the potential difference between the work material and the tool is large enough to cause a breakdown in the fluid medium, fed into the gap between the tool and workpiece under pressure, producing a conductive spark channel. The fluid medium, which is normally mineral oil or kerosene, has several functions. It serves as a dielectric fluid and coolant, maintains a uniform resistance to the flow of current, and removes the eroded material. The sparking, which occurs at rate of thousands of times per second, always occurs at the point where the gap between the tool and workpiece is smallest and develops so much heat that a small amount of material is evaporated and dispersed into the fluid. The material surface has a characteristic appearance composed numerous small craters.A wide variety of machining operations or processes based on the same metal—cutting principle are available；among the most common are milling and drilling carried out on various machine tools. By varying the tool shape and the pattern of relative work-tool motions, many different shapes can be produced.Turning Turning can be characterized as: mass reducing, solid state of work material, mechanical primary basic process-fracture. The turning process, which is the best known and most widely used mass-reducing process, is employed to manufacture all types of cylindrical shapes by removing material in the form of chips from the work material with a cutting tool. The work material rotates and the cutting tool is fed longitudinally. The cutting tool is much harder and more wear resistant than the work material. A variety of types of lathes are employed, some of which are automatic in operation. The lathes are usually powered by electric motors which, through various gears, supply the necessary torque to the work material and provide the feed motion to the tool.The stages or steps in a casting process are the making of a suitab1e mo1d, the melting of the material, the filling or pouring of the material into the cavity, and the solidification. Depending on the mold material, different properties and dimensional accuracies are obtained. Equipment used in a casting process includes furnaces, mold--making machinery, and casting machines.Casting Casting can be characterized as: mass conserving,fluid state of material,mechanical primary basic process—filling of the die cavity. Casting is one of the oldest manufacturing methods and one of the best known processes. The material is melted and poured into a die cavity corresponding to the desired geometry. The fluid material takes the shape of the die cavity and this geometry is finally stabilized by the solidification of the material.阅读材料 8制造过程举例铸造铸造可以描述为：大量流动态的材料经过基本的机械加工工艺—充满模具的型腔。
(建筑工程管理)过程装备与控制工程专业英语翻译
（建筑工程管理）过程装备与控制工程专业英语翻译GeneralEquilibriumConditionsofASystem力系的一般平衡条件在这一部分，我们将研究为了使一个物体保持平衡，作用在其上的力和力偶所必须满足的条件。
根据牛顿第一定律，施加在一个静止物体上的力系的合力一定为零。
然而，请注意这个定律对力矩或力系的转动效应只字未提。
显然，合力矩也一定为零，否则物体将会转动。
这里的基本问题是原先叙述的牛顿第一定律（和第二定律）只适用于非常小的物体，或者尺寸可以忽略的非零质量的粒子。
然而，它可以扩展到如下所述的有限尺寸的物体。
考虑一个由两个质点组成的系统，假设和为它们之间的相互作用力(图.1.1)。
这些力称为内力，因为它们是由于系统内部的物体之间的相互作用而产生的。
假定内力服从牛顿第三定律，我们有。
假如还有质点与系统外物体之间的相互作用力施加在质点上，如和,这些力称为外力。
显然，作用在一个特定粒子上的力一定有相同的应用，因为粒子的尺寸可以忽略。
如果系统内的每一个质点处于平衡，我们就可以说系统是平衡的。
在本例中，依据牛顿第一定律，作用在每个质点上的力的合力一定为零。
对质点A我们有：而对质点B有：作用在系统上的力的总和为：现在我们来研究这些力对于同一点P的合力矩。
由图1.1，我们有：由于力和有相同的作用线，力矩的条件可以改写为但；所以力和力矩的条件简化为和换句话说，如果系统处于平衡，那么作用在其上的合外力一定为零，而且这些力对于任一点的合力矩也为零。
内力不需要考虑，因为它们的效应相互抵消了。
如果系统处于平衡，那么and(1.1)这里是作用在系统上的所有外力的总和，而是这些力对任意点的合力矩，包括系统中可能作用有的力偶的矩。
方程（1.1）是平衡的必要条件；也就是说，如果系统处于平衡，必须满足这些方程。
一般来说它们不是平衡的充分条件。
然而，这并不会带来任何困难，因为我们的研究仅涉及平衡系统。
对于刚体，方程（1.1）既是其平衡的必要条件也是充分条件。
过程装备与控制工程专业英语翻译1
The reactions for th1.2 (c)]can be found the same manner
For the cantilever beam[Fig.1.2(b)], the action of the applied load q is equilibrated by a verticalforce RAand a couple MAacting at the fixed support, as shown in the figure. From a summationof forces in vertical direction , we include that
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修改过程装备与控制工程专业英语翻译Unit 16 压力容器及其部件压力容器时不泄露的容器。
它们有各种尺寸。
最小的直径不到一英寸，最大的直径能达到150英尺甚至更大。
某些是埋在地下或海洋深处，多数是安放在地上或支撑在平台上，还有一些实际上是在航天飞行器中的贮槽和液压装置中。
由于内部压力，容器被设计成各种形状和尺寸。
内部的压力可能低到1英寸，水的表面压力可能达到300000多磅。
普通的单层表面建筑压力是15到5000磅，虽然有很多容器的设计压力高出或低于这个范围。
ASME锅炉和压力标准中第八卷第一节指定一个范围从15磅在底部到上限，然而，内部压力在3000磅以上，ASME 标准，第八卷第一节，指出考虑特殊设计的情况是必要的。
压力容器的典型部件描述如下:圆柱壳体在石化工业中对于结构压力容器圆柱壳体是经常被用到的，它是很容易制造、安装并且维修很经济。
虽然在一些场合应用载荷和外压控制，要求的厚度通常由内压决定。
其他因素如热应力和不连续压力可能有要求厚度决定。
成型的封头许多的端封头和过度部分有设计工程师选择。
用一种结构相对另一种依靠很多因素，如成型方法、材料成本、和空间限。
一些经常应用的成型封头是:带凸缘的封头这些封头通常在较低压力的压力设备中，例如汽油罐和锅炉。
有些也应用在较高压力的但是较小直径的设备中。
设计和结构的许多细节在ASME 标准，第八卷第一节中给出。
半球形封头通常，在一个给定温度和压力下半球形的要求厚度是相同直径和材料圆柱壳体的一半。
假如我们用镍和钛昂贵的合金建造实心或覆盖形半球形封头，这样是很经济的。
假如使用碳钢，然而，由于这高价的制造费用就不比凸缘形和碟形的封头经济。
半球形封头经常通过部分三角形结构加工，也可以通过旋转法或施压法加工。
由于半球形封头比与它们连接的圆柱壳体薄，所以在封头与壳体连接区域必须是等高的，以便减小不连续区域的影响。
椭圆与准球形封头这样的封头是十分普遍的在压力容器中。
它们的厚度与连接壳体是一样的。
这就简化了焊接安装的工作。
因此，由于这边意外的区域所需的厚度小于封头的实际厚度，多余的部分就可以用于这些区域内接管的补强。
许多工厂都可以提供不同直径和厚度的封头而且在价格上有很强的竞争力。
锥型和准锥形封头这些封头可以用在料斗和塔的底部挡板上，而且它们也可用做不同直径圆柱的过渡区域。
由于在链接区存在不平衡力，所以必须把圆锥到圆柱的链接区考虑成圆锥形设计的一部分。
因为这些较大的力，ASME标准，八卷一节中，规定锥形内部施加压力顶角限制成小于30度。
盲法兰盖，盖版，和法兰一个较为常用的压力容器封头是无支撑的平封头或平盖。
这可能由完整壳体组成或由整体焊接而成，也可能由螺栓或快速开关装置与整体连接。
可能是圆形、方形、矩形或其他形状。
这些使用螺栓和垫片连接的平封头称为法兰盖。
通常，在两个法兰之间放一个垫片，由螺栓将两个法兰相连。
虽然法兰可能是圆形或非圆形的，但是它们有相同的厚度。
开口和接管所有的过程容器都需要有开口来使物料进出。
对于一些容器，物料是大量的或内部空间经常变化的，通常通道是由把整个封头或一部分移走而形成的。
然而，对于大多数容器，物料是通过封头筒体上的开口进出的,,这些开口与接管和管线相连接的。
除了这些，还需要其他的开口，例如人进入容器的人孔。
另外一些从外面检测容器的手孔的开口也是必要的,另外,一些清理容器的和排放的开口也是必需的。
这些开口不总是有一个接管被安装在开口。
有时挡板上有一个人孔盖或或手孔盖,这些直接被焊接或用螺栓连接在容器上。
支撑大多数立式容器由裙座支撑。
由于它们转移剪切力形成的载荷,所以裙座是经济的。
它们总是通过地脚螺栓和支撑板把载荷传递到地基上。
腿式支座容器是较轻的，并且支脚到容器的底部提供了容易通过的的通道。
一个经济的设计是支脚直接连在容器上，并且转移了由剪切产生的载荷。
卧式容器通常由鞍座支撑。
由于壳体太薄而不能把力传递到鞍座上就需要安装加强环。
热膨胀问题应该被考虑。
Unit 17 压力容器的设计容器的选择虽然很多因素决定着容器的选择，但是影响选择的两个基本条件是安全和经济。
许多内容都被考虑，像材料的供应，抗腐蚀能力，材料的强度，载荷的类型和大小，安装的地点包括风载荷和地震载荷，制造的地点，容器安装的方位和在设备安装地点劳动力的供给情况。
随着特殊压力容器在石油化工和其他工业的广泛应用，恰当材料的选用很快变成一个主要问题。
对于容器最常用的材料是碳钢。
许多其他特殊材料也被应用在抗腐蚀或者储存液体而材料的性质不降低。
材料的替代十分广泛并且表面处理和涂层被广泛应用。
设计工程师必须与工艺工程师进行交流，以便所有使用材料有助于容器的整体完整性。
对于这些现场安装的容器，与在现场建造的相比，不管容器制造的不利条件如何，必须建立焊缝安全的质量保证。
对射线探伤，应力消除，和其他在现场的操作必须做好预先准备。
对于那些在低温环境下运行或盛装液体的容器，必须注意保证材料在低温下的抗击能力。
为了满足这种特殊性能，容器可能要求特种高合金钢，有色金属，或一些特别的热处理。
那种压力容器标注被应用首先考虑的是，是否在安装地点有压力容器法规。
如果有，就按规定标准进行。
如果管辖部门已经决定采用ASME规范的第八篇，那么需要确定的只是选用第一分篇还是第二分篇。
关于要用第一分篇还是第二分篇有很多观点，但是底线是经济。
第一分篇用近似的公式，图表，和曲线图进行简单的计算。
第二分篇，在另一方面，用复杂的公式、图表、还有在应力报告中必须被提供的分析设计方法。
有时，由于对按第一分篇设计的容器在最低要求之外又增加了许多附加要求，因此按第二分篇设计并选取较高的许用应力可能更为经济。
特殊的设计要求除了所有设备所需的标准信息，例如压力、设计温度、形状和尺寸，很多其他项信息也是必要的并且必须要被记录下来。
腐蚀和侵蚀量应该被给出，并且适合材料和保护方法必须被注明。
由于所需要的特殊设计细节，盛装液体的类型，像致命的，必须被注明。
容器受支撑位置状态，立式或卧式的和支撑地点被必须也被给出，因为受支撑的设备和管线所产生的载荷也要被记录。
坐落位置也得给出，因为风、雪、地震的要求可能被确定。
冲击载荷和循环条件也要给出。
对于ASME标准，第八篇第二分篇，按照AD-160给出是否进行疲劳分析的说明。
如果需要进行疲劳分析，这个特殊的周期和载荷也要被给出。
另外，设计技术条件要指出是否包括持续的或瞬时载荷。
许用应力随着载荷的改变而改变。
设计报告和计算如果在用户的设计条件中包含应力分析计算的话，ASME标准，第八篇第二分篇，规定要求具有一个正规的设计报告。
这些计算由一个注册过的在压力容器的设计方面有丰富经验的专业的工程师准备和鉴定。
如同用户设计条件一样，制造商的设计报告以及有关制造厂数据报告的证明书都是强制性的。
这由制造厂以文件形式保存五年。
材料的说明书所有的标准都有材料的详细说明和要求，用于描述哪种材料是允许使用的。
被允许的这些材料特殊的标准被列出或被限制在被允许的应力值范围内。
根据规范和标准，对于一个特殊过程的容器的许用材料是被限制的。
例如，仅SA与SB指定的材料才可能用在ASME锅炉和压力容器制造中。
安全因子为了在那个“依据复杂的理论与各种失效模式下得出的精确公式”和“用于确定厚度和压力水准的实际设计公式”之间提供一个安全余量，安全因子被应用在确定各种材料的性能，这种性能决定着许用压力值。
安全因子直接与理论和失败模型式相关、和每种规定的特殊规范和每种水平的实际应力被确定和估计的程度有关。
纵观世界，多种安全因子被用在材料的设计当中，用于在锅炉、压力容器和管道的设计中建立许用应力。
对于这个温度变化达到建立许用应力的蠕变和断裂的温度，这所有得到的许用应力是在屈服强度上确定的。
在许多国家，这种因素被应用在经过许多次试验而建立起来的一系列数据上。
在其他国家，数据是由低的屈服强度和高的屈服强度决定的。
在另外的一些国家，对于设计部件这真正的数据是由多次测试而确定的。
部分的设计归因于设计的公式。
并不是所有国家用极限拉伸强度作为确定许用应力的标准。
Unit 18 蒸馏设备定义蒸馏是一种基于分离材料的相对挥发度和原始混合物各组分间的相变化为基础的分离过程。
举个简单的例子，液体混合物的中易挥发组分通过加热被汽化。
留下相对不易挥发的成分作为残液。
当一种以上易挥发成分要从其他组分中分离出来，蒸馏与蒸发和干燥稍有不同的是在，收集易挥发成分的方式上，在分离难易程度上，在操作的复杂程度上。
通常蒸馏适用于液体混合物。
但也有例外，典型的就是木材和煤的干馏，它是从固体中分离液体成分。
化学工程的现代科学技术是把蒸馏作为应用几种原理与设计方法的单元操作。
不管被处理的材料或是被涉及的行业。
蒸馏的设计的趋势是满足工艺的一般需求，而不是各工业的特殊需求。
范围蒸馏设备被制造成各种形状，构造和尺寸，去满足处理特殊的混合物和制造产品的条件要求。
所使用的设备类型的选择的选择依据所蒸发材料的物理特性、所达到的分离成度和操作规模大小为基础。
选择蒸馏系统的部件尺寸只是依据手册与教科书给出的成熟方法所设计的，但是必须有经验丰富的的蒸馏设备制造厂来调整。
目的是指导在设备类型和构造的选择，省去在详细设计方面的说明要求的冗长论述。
理论用来决定分离成度和设计尺寸的蒸馏设备是由蒸发溶液平衡数据、热和材料平衡、允许会发速率、分离率和热传递效率。
一种易挥发组分对于从一个不易挥发的残留物中蒸发的间歇操作计算是简单的。
无论间歇或连续过程中随着组分的数量变得越多，计算变得更加复杂。
虽然读者不能在设备设计中寻找到详细的说明，但是他最好知道进行完整设计所需的信息，这个第一要求是在操作温度和压力范围内的每一种组分物理数据如下(1) 液体的比容(2) 蒸汽的比容(3) 任意一种组分在其他组分的溶解度，假如使用直接蒸汽需要给出在水中的溶解度。
(4) 气液比(5) 液体的潜热(6) 液体和蒸汽的联系(7) 表面张力(避免物沫夹带的近似值)(8) 液体和正空的热导性(9) 泡沫特性(10) 对可能结构材料的腐蚀程度蒸馏设备分类蒸馏设备可以被广泛的分类为间歇操作和连续性操作设备。
设备的操作特性，在某种情况下，受完成操作的难易的影响。
简单的分离有简单的蒸馏来完成，难得分离由分馏来完成。
蒸馏设备的分级先是在表4.1所制造蒸馏设备的运行条件有在一个很大的变化范围，在石油炼制过程中，温度对分离来讲，可以在从较低的液氮到700--800 F范围变化。
压力变化在从真空度到1000psi变化。
并且流量可以从几加仑到50000加仑每小时变化。
分离的变化范围从来自实际不易蒸发的植物油中分离己烷的简单操作到在普通水中分离重水的困难操作。
Unit 19 换热器的种类换热器主要是用于冷热流束之间进行换热的设备。