Corrosion Sensors
Introduction
Electrochemical engineering is the branch of chemical engineering that deals with technological applications of electrochemical phenomena, such as electrosynthesis of chemicals, electrodeposition and refining of metals, flow batteries and fuel cells, surface modification by electrodeposition, electrochemical separations and corrosion. This discipline is an overlap between electrochemistry and chemical engineering.
According to IUPAC, the term electrochemical engineering is reserved for electrically intensive processes for industrial or energy storage applications, and should not be confused with applied electrochemistry, which includes small batteries, amperometric sensors, microfluidic devices, microelectrodes, solid-state devices, voltammetry on disk electrodes, etc.
More than 6% of electricity is consumed by large-scale electrochemical operations in the United States.[1].
Scope
Electrochemical engineering combines the study of heterogeneous charge transfer at electrode/electrolyte interfaces with the development of practical materials and processes. Fundamental considerations include electrode materials and the kinetics of redox species. The development of the technology involves the study of electrochemical reactors, their potential and current layout, mass transport conditions, hydrodynamics, geometry and components, as well as the quantification of their overall performance in terms of reaction yield, conversion efficiency and energy efficiency. Industrial developments require more reactor and process design, manufacturing methods, testing and product development.
Electrochemical engineering considers current distribution, fluid flow, mass transfer, and the kinetics of electro reactions to design efficient electrochemical reactors.[2].
Most electrochemical operations are performed in filter press reactors with parallel plate electrodes or, less frequently, in stirred tanks with rotating cylinder electrodes. Fuel cell and flow cells are types of filter press reactors. Most of them are continuous operations.
History
This branch of engineering gradually emerged from chemical engineering as sources of electrical energy became available in the mid-century. Michael Faraday described his laws of electrolysis in 1833, reporting for the first time the amount of electric charge and the mass converted. In 1886, Charles Martin Hall developed a cheap electrochemical process for extracting aluminum from its ore in molten salts, constituting the first large-scale electrochemical industry. Later, Hamilton Castner") improved the aluminum manufacturing process and devised the electrolysis of brine in large mercury cells for the production of chlorine and caustic soda, effectively founding the chlor-alkali industry with Karl Kellner in 1892. The following year, Paul L. Hulin patented electrochemical filter press cells in France. Charles Frederick Burgess") developed the electrolytic refining of iron ca. 1904 and later ran a successful battery company. Burgess published one of the first texts on the field in 1920. During the first three decades of the century, industrial electrochemistry followed an empirical approach.[3].