化工专业英语复习2

上课讲过的课文

Typical Activities of Chemical Engineers

After completing this unit，you should be able to:

1. Identify the differences between the work of chemists and that of chemical engineers

2. Describe some of the typical activities of the chemical engineer

The classical role of the chemical engineer is to take the discoveries made by the chemist in the laboratory and develop them into money-making，commercial-scale chemical processes. The chemist works in test tubes（小试）and Parr bombs with very small quantities of reactants（反应剂）and products (e.g 100 ml)，usually running“batch”，constant-temperature（恒温）experiments. Reactants are placed in a small container in a constant-temperature bath.

A catalyst（催化剂）is added and the reactions proceed with time. Samples are taken at appropriate intervals to follow the consumption（消耗）of the reactants and the production（生产）of products as time progresses.

By contrast, the chemical engineer typically works with much larger quantities of material and with very large (and expensive) equipment. Reactor s（反应器）can hold 1,000 gallons to 10,000 gallons or more. Distillation columns （精馏塔）can be over 100 feet high and 10 to 30 feet in diameter（直径）. The capital investment for one process unit in a chemical plant（化工厂）may exceed $ 100 million!

The chemical engineer is often involved in “scaling up”（放大）a chemist-developed small-scale reactor and separation system（分离系统）to a very large commercial plant. The chemical engineer must work closely with the chemist in order to understand thoroughly the chemistry involved in the process and to make sure that the chemist gets the reaction kinetic data and the physical property（物理性质)data needed to design, operate, and optimize(优化）the process. This is why the chemical engineering curriculum（课程）contains so many chemistry courses.

The chemical engineer must also work closely with mechanical（机械）, electrical（电工）, and metallurgical （冶金）engineers in order to design and operate the physical equipment in a plant –the reactor, tanks, distillation columns, heat exchangers（换热器）, pump s（泵）, compressors（压缩机）, control(控制）and instrumentation devices（仪器设备）, and so on. One big item that is always on such an equipment list is piping（管道）. One of the most impression features of a typical chemical plant is the tremendous（巨大的）number of pipes running（管道铺设）all over the site, literally（逐字的）hundreds of miles in many plants. These pipes transfer process（过程）materials (gases and liquids) into and out of the plant. They also carry utilities（公用工程）(steam, cooling water, air, nitrogen, and refrigerant) （冷却剂）to the process units.

To commercialize（总结）the laboratory chemistry, the chemical engineer is involved in development design, construction（建造）, operation（运行）, sales and research. The terminology（术语）used to label these functions is by no means uniform（绝不一样）from company to company, but a rose by any other name is still a rose．Let us describe each of these functions briefly. It should be emphasized that the jobs we shall discuss are “typical”and ”classical”, but are by no means the only things that chemical engineers do. The chemical engineer has a broad background in mathematics, chemistry, and physics. Therefore, he or she can and does, fill a rich variety（种类）of jobs in industry，government, and academia.（科研院所）

第二篇

1. Development

Development is the intermediate（中间）step required in passing from a laboratory-size process to a commercial-size process. The “pilot-plant”（中试）process involved in development might involve reactors that are five gallons in capacity and distillation columns that are three inches in diameter. Development is usually part of the commercialization（商业化）of a chemical process because the scale-up problem is a very difficult one. Jumping directly from test tubes to 10,000-gallon reactors can be a tricky（棘手的）and sometimes dangerous endeavor（工作）. Some of the subtle（细小的）problems involved which are not at all obvious to the uninitiated（未计划的）include mixing imperfections,（有缺陷）increasing radial（辐射）temperature gradients （阶梯形）, and decreasing ratios（比率）of heat transfer areas to heat generation rates.

The chemical engineer works with the chemist and a team of other engineers to design, construct, and operate the pilot plant. The design aspect involves specifying（指定）equipment sizes, configuration（构造）, and materials of construction. Usually pilot plants are designed to be quite flexible, so that a wide variety of conditions and configurations can be evaluated（评估）.

Once the pilot plant is operational, performance and optimization（最大化）data can be obtained in order to evaluate the process from an economic point of view. The profitability is assessed at each stage of the