Marine Clays - Passing AC currents

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SUMMARY

This discussion focuses on the implications of using AC currents (230 V, 60 Hz) to electrically heat clayey soils with a moisture content of 55% and 0.5 M salt solutions (NaCl/KCl). Participants confirm that electrolysis of water and electrolytes occurs, producing gases such as Cl2 and H2, which can lead to further reactions like chlorate generation. Concerns about shorting power lines are addressed, and it is suggested to use a rheostat to manage load resistance. A rule of thumb indicates that no more than 20% of the energy input is likely lost to ionization during this process.

PREREQUISITES
  • Understanding of electrolysis and its effects on saline solutions
  • Familiarity with AC electrical systems, specifically 230 V, 60 Hz
  • Knowledge of rheostats and their application in electrical circuits
  • Basic principles of thermal energy transfer in soils
NEXT STEPS
  • Research the effects of electrolysis on different types of salts in clayey soils
  • Learn about the use of rheostats in controlling electrical loads
  • Investigate methods for calculating energy loss in electrolysis
  • Explore thermal conductivity measurements in clayey soils
USEFUL FOR

Engineers, soil scientists, and researchers involved in geotechnical projects or those exploring the electrical heating of soils for agricultural or construction purposes.

wildwildwest
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I am working on a project involving electrically heating clayey soils (having 55% moisture content and 0.5 M salt (nacl/KCl) solutions in the pore space.

Does anybody know if electrolysis of water/electrolyte is a concern with AC currents (230 V, 60 Hz frequencies)?

Thanks,
WWW :smile:
 
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I'm not sure what you mean by "is a concern". Yes, the water will be electrolysed, but as long as you don't stick your fingers in the clay, you should be okay. Unless your concerned about shorting the power line, which is a valid concern. I'd use a rheostat in series with the clay and start with a high load resistance and keep turning it down in each successive try.

PS : Standard conductivity measurements of water are done using AC, and counts on the conductivity from the ions.
 
clays - electrical heating

Thanks for the reply,

Yes, my concern was with the shorting of the power line. Does anyone know of 'rule of thumb'/'back of envelope' calculations for determining how much of power energy put in goes into heating the clay and how much is lost in electrolysis?


Thanks,
WWW
 
When a chloride is electrolyzed, Cl2 gas will be produced. That's in addition to the H2, of course. Also, the Cl2 reacts further, which ends up with the generation of chlorate. Would any of these products cause a problem?
 
wildwildwest said:
Does anyone know of 'rule of thumb'/'back of envelope' calculations for determining how much of power energy put in goes into heating the clay and how much is lost in electrolysis?

You can calculate the energy going into ionization (actually deposition, since most salt are ionized by the polarity of water) if you know what salts are dissolved in the clay, and what their concentrations are. The rest goes into heating the clay.

I'd be surprised if more than 20% went into ionization/deposition.
 

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