Non-catalytic reduction of total acid number (TAN) of naphthenic acids (NAs) using supercritical methanol

Pradip Chandra Mandal, Wahyudiono, Mitsuru Sasaki, Motonobu Goto

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Naphthenic acid (NA) present in crude oil leads to corrosion problems within oil refineries. The objective of this study is to reduce total acid number (TAN) from NA using a catalyst-free supercritical methanol (SC-MeOH), a process novel in this area. The reaction was carried out in an 8.8 mL batch reactor fabricated from Hastelloy C-276 with respective design temperature and pressure of 500°C and 50 MPa. The ability of SC-MeOH to reduce TAN was explored at temperatures from 300 to 350°C and methanol partial pressure (MPP) of 10 MPa. Experimental results revealed that TAN removal was 99.77% at a temperature of 350°C, MPP of 10 MPa and reaction time of 60 min. The TAN removal followed first order kinetics, with Arrhenius parameters of activation energy 5.78 kcal/ mol and a pre-exponential factor 1.56 s- 1. These results suggest that SC-MeOH is capable of reducing TAN from NA with no use of catalyst or additives.

Original languageEnglish
Pages (from-to)641-644
Number of pages4
JournalFuel Processing Technology
Publication statusPublished - 2013 Feb
Externally publishedYes


  • Acid number
  • Batch reactor
  • Heavy oil
  • Naphthenic acid
  • Supercritical methanol

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology


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