The biodiesel processing from oil of yellowfin tuna [thunnus albacares (Bonnaterre,1788)] offal using acid catalyst

Biodiesel is one of the alternative fuels to meet the need of the diesel fuel in indonesia. one of potential animal oil/fat to be utilized as biodiesel raw material is offal from yellowfin tuna. the objective of the study is to know the free fatty acid (ffa) levels of raw material,influence of the h2so4 concentration as catalyst on biodiesel conversion,composition of the main fatty acid compounds from biodiesel,and physical characteristics of biodiesel through esterification and transesterification reaction. in transesterification phase,the variabel is h2so4 concentration 1.25%,1.50% and 1.75% at 60 °c and 65 °c with oil to methanol molar ratio of 1:9. based on experiment results,the know that: ffa content from oli of yellowfin tuna offal amounted to 2.33%,the largest conversion of methyl ester from spectra of h-nmr,ft-ir,gc-ms and astm was produced from the treatment with 1.50% h2so4 at 65 °c,with an average yield of 89.09% and the conversion value of methyl ester was 52.63%. the main compounds of fatty acids that formed biodiesel were palmatic acid (43.64%) and oleic acid (32.08%). the physical characteristics of biodiesel according to the national standards of indonesia (nsi) were specific density of 0.8637 60/60 °f g ml–1 kinematic viscosity of 2.555 mm2 s–1,pour point is -3 °c and cloud point of 25 °c,while flash point of 25 °c and water content of 0.20% was not consistent with the sni. © 2016 penerbit utm press. all rights reserved.