Comparison chlor-alkali cells

Comparisons between analytical and synthetic systems are not always easy to draw in view of the different conditions employed. Thus, the thermodynamically reversible and mechanistically simplistic hydrogen and chlorine evolution reactions, well behaved in analytical studies at platinized platinum, are both beset (chlorine most severely) in large-scale chlor-alkali cells by adherence of gas bubbles to the electrode surface. 

Figure 3.14 Comparison of the energy consumption in the three cell technologies for chlor-alkali production. Full lines represent electrolysis only broken lines represent total energy consumption including evaporation and heating the electrolyte.

The dominant role of energy consumption in chlor-alkali economics makes it the most important aspect of cell performance. If one type of cell can offer substantially lower energy consumption than others, it will have a major advantage in any techno-economic comparison. This fact is the single most important reason for the ongoing conversion of the industry to membrane cells. 

Finally, there are the ubiquitous intangibles such as corporate agreements or deals between the chlor-alkali producer and the cell technology supplier or its parent organization, the membrane supplier, and the anode vendor. This is sometimes a reality, in which case the cell technology comparison may become moot. 

Published experimental smdies of the FM21 cell are fewer in number but include comparisons of mass transport in the FMO1 and FM21 cells [48,49]. In addition to operation in the chlor-alkali industry [50], the electrolyzer has been used for diverse applications including the removal of nitrate from nuclear waste streams [51], the destruction of contaminated solids via silver(ll) [52,53], and the electrosynthesis of a pharmaceutical intermediate [54]. 

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