Investigation of the content of unsaturated hydrocarbons in transformer oils using IR spectroscopy

THE  PURPOSE. To  analyze  the  current  understanding  of  unsaturated  hydrocarbons with  double  C=C  bonds  in  mineral  transformer  oils  and  evaluate  the  effectiveness  of  modern methods of controlling the content of these compounds in oils. Develop an instrumental way to control  unsaturated  compounds  in  mineral oils  by  means of  IR  spectroscopy. Study  the  change in  the  content  of  unsaturated  hydrocarbons  in  oils  during  thermal  degradation.  Study  the effectiveness of the adsorption purification of oils to remove unsaturated compounds from oils. METHODS. To  determine  the  content  in  mineral  oils  of  unsaturated  hydrocarbons  used  IR spectroscopy  in  the  near  infrared  spectral  region.  Artificial  thermal  degradation  of  oils  was carried  out  at  temperatures  of  100 and  150 ºC. For adsorption purification of oils silica gels brands  KSKG,  AS230SH,  as  well  as  Fuller's  Earth  adsorbent  were  used. RESULTS. Spectral range 4750÷4500 cm^-1 and  method  of  IR  spectra  transformation  were  chosen  to  control  the content  of  unsaturated  compounds  with  double  C=C  bonds  in  the  oil.  As  a  result  of  model experiments,  it  is  clearly  demonstrated  that  the  content  of  unsaturated  hydrocarbons  increases with  increasing  degree  of  thermal  degradation  of  oils.  It  is  shown  that  adsorption  purification has a low efficiency with respect to unsaturated compounds. An algorithm for differentiation of fresh mineral transformer oils produced by hydrocracking technology from the regenerated oils is  proposed. CONCLUSION. The  highest  content  of  unsaturated  compounds  is  contained  in mineral  oils  produced  by  technologies  other  than  hydrocracking.  Thermo-oxidative  impact  on oil  during  its  operation  leads  to  an  increase  in  the  content  of  unsaturated  hydrocarbons  in  the oil.  The  content  of  unsaturated  hydrocarbons  in  the  mineral  transformer  oil  characterizes  the degree of degradation of its hydrocarbon base that cannot be recovered during regeneration.

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