英语翻译Lesson 10Gas AbsorptionGas absorption is an important unit operation chemical engineering,particularly in the heavy chemical industry.In the purification of coal gas and synthetic gas as well as in the manufacture of hydrochloric acid,sul

英语翻译Lesson 10Gas AbsorptionGas absorption is an important unit operation chemical engineering,particularly in the heavy chemical industry.In the purification of coal gas and synthetic gas as well as in the manufacture of hydrochloric acid,sul
英语翻译
Lesson 10
Gas Absorption
Gas absorption is an important unit operation chemical engineering,particularly in the heavy chemical industry.In the purification of coal gas and synthetic gas as well as in the manufacture of hydrochloric acid,sulphuric acid,metric acid,soda ash and bleaching lyes,to mention only the most striking examples,gas absorption is the essential feature of the process.Since the twenties extensive research has been carried out with the result that the knowledge of this unit operation has increased considerably.
The essential element in gas absorption is the mass transfer between two fluid phases,if necessary,combined with chemical reactions.The latter are mainly restricted to the liquid phases although,for instance in the manufacture of nitric acid,the chemical reaction may also occur in the gas phase.
It will be understood that in such a heterogeneous process as gas absorption a large contact area is a primary requisite for rapid transfer.
There are three ways in which a large contact area can be established:
1.The liquid is brought in contact with the gas in the form of thin films(film scrubbers).
2.The liquid is dispersed in the gas in the form of minute drops(spray scrubbers).
3.The gas is dispersed in the liquid in the form of small bubbles(bubble scrubbers).
All apparatus applied in gas absorption practice is based on one of these three principles or on a combination of them.
Here serious problems are encountered which have only been partly solved.The first things to discover when dealing with a process of mass transfer are the size of the contact area and the way in which this size depends on the various condition of the experiment.The most complete answer to this question can be even for apparatus of type 1.The simplest representative of this type is the wetted wall column,the contact area of which may be determined with great accuracy.For packed column the question cannot be answered so easily,since it cannot be exactly ascertained which part of the packing will be wetted.For the sake of simplicity the contact area may be considered to be equal to the total area of the packing material.In apparatus in which gases or liquids are dispersed,type 2 and 3,determination of the contact area is almost impossible.
Only in the last few years has insight been obtained into the conduct of gas bubbles during their formation in an ascension through liquids,although much work is still to be done in this field.
Absorption,or gas absorption,is a unit operation used in the chemical industry to separate gases by washing or scrubbing a gas mixture with a suitable liquid.One or more of the constituents of the gas mixture will dissolve or be absorbed in the liquid and can thus be removed from the mixture.In some systems,this gaseous constituent forms a physical solution with the liquid or the solvent,and in other cases,it reacts with the liquid chemically.

英语翻译Lesson 10Gas AbsorptionGas absorption is an important unit operation chemical engineering,particularly in the heavy chemical industry.In the purification of coal gas and synthetic gas as well as in the manufacture of hydrochloric acid,sul
课10气体AbsorptionGas吸收是一个重要的化工单元操作,特别是在重化学工业.煤气的净化和合成气体以及生产的盐酸、硫酸、指标酸、碳酸钠和漂白碱液,只提到最引人注目的例子,气体吸收过程的基本特征.自二十年代进行了广泛的研究结果,本单元操作的知识大大增加了.气体吸收的基本要素是两个流体阶段之间的传质,如果有必要,结合化学反应.后者主要局限于液体阶段虽然,例如制造硝酸,也可能出现在气相化学反应.就会明白,在这种异构过程气体吸收大量接触面积是一个主要的快速转移.有三种方法可以建立一个大的接触面积:1.带来的液体接触的气体薄膜的形式(电影洗涤塔)2.液体的形式分散在气分钟滴(喷淋洗涤塔).气体分散在液体小气泡的形式(泡沫洗涤塔).所有设备应用于气体吸收实践是基于这三个原则之一或它们的组合.在这里遇到严重的问题,只有部分解决.首先发现在处理的过程传质接触面积的大小,这个大小的方式取决于实验的各种条件.最完整的答案可以甚至1型的装置.最简单的这种类型的代表是湿墙柱,这可能是确定的接触面积的准确性.对填充柱不能那么容易回答的问题,因为它不能完全确定的哪一部分包装会湿.为了简单起见,接触面积可能被认为是包装材料的总面积.在装置中气体或液体分散,类型2和3,确定接触面积几乎是不可能的.只有在过去的几年中洞察力获得气泡的行为在他们通过液体形成的提升,虽然仍需要做大量的工作.或气体吸收,吸收是一个单元操作用于化工分离气体清洗或擦拭与合适的液体气体混合物.一个或多个组分的气体混合物会解散或被吸收的液体,因此可以从混合物中删除.在一些系统中,这种气体成分形成一个物理解决方案与液体或溶剂,而在其他情况下,它与液体化学反应.