Energy and Mass Transfers

3 Mass Transfer Mechanisms and Processes

3.1. Introduction

In almost all areas of industrial production, mass transfer occurs during various manufacturing stages, or at least in one of the stages. Remember that both during the course of purification operations and in manufacturing phases, mass transfer is indeed required.

The examples are numerous and varied. Take, as one example, the refining of petroleum products, where, starting from crude oil, via distillation, various products are developed, such as gasoline, heating oil, heavy fuel oil, kerosene and bitumen.

It is also the case for the production of drinking water by seawater desalination, where water is forced to migrate outside of the saline solution, yielding pure water. Another example is uranium enrichment, where, starting from a mixture of U²³⁵ and U²³⁸ isotopes, low in U²³⁵, a compound is developed that is increasingly rich in U²³⁵, which constitutes the basic fuel used in nuclear reactors.

Moreover, environmental studies consider the evolution of the composition of the atmosphere or the predictions of occurrences of acid rain, or the analysis of the evolution of the ozone layer. All these studies imply a good knowledge of mass transfer mechanisms underlying each phenomenon.

Other applications are of a great interest to industry. In particular, we will address mass transfers by absorption, which are are mainly used to purify gaseous industrial effluents before their release into the atmosphere, with a view to ...