Improvement of cold filter plugging point of diesel fuel and biobutanol mixtures

Zbog energijske krize uzrokovane sve manjim konvencionalnim zalihama nafte te emisije stakleničkih plinova i s time povezanog globalnog zagrijavanja javlja se zabrinutost među ljudskom populacijom. Osim toga, CO2, NOx spojevi i lebdeće čestice potencijalni su uzročnici respiratornih i kardiovaskularnih bolesti. Biobutanol je zamjensko gorivo koje se može proizvesti iz otpadne biomase, ima dobru mješljivost s dizelskim gorivom te se provode istraživanja kako bi ga se što uspješnije ukomponiralo u tržišna motorna goriva. U ovom radu ispitivana su niskotemperaturna svojstva mješavina dizelskog goriva i n-butanola u udjelima do 10 vol. % bez i uz dodatak polimernih PAMA aditiva. PAMA aditivu sintetiziranom radikalskom kopolimerizacijom određena je konverzija monomera, a svim upotrebljenim aditivima raspodjela molekulskih masa metodom kromatografije na propusnom gelu (GPC) i sastav nuklearnom magnetskom rezonancijom (1H NMR). Termogravimetrijskom analizom (TGA) komercijalnih aditiva određen je udio aktivnog polimera u komercijalnoj otopini, na temelju čega su pripravljene vlastite otopine PAMA aditiva. Metodom plinske kromatografije dobivena je raspodjela n-parafina u dizelskom gorivu pri čemu se pokazalo da n-parafini čine 23,02 mas. % mase ukupnog uzorka. Rezultati ispitivanja niskotemperaturnih svojstava pokazali su da sintetizirani PAMA aditivi nemaju utjecaj na točku filtrabilnosti niti na dizelsko gorivo niti na njegove mješavine s n-butanolom, dok je točka tečenja snižena sa -18 °C na -24 °C, odnosno -30 °C. Diferencijalnom pretražnom kalorimetrijom (DSC) istražena je kristalizacija parafina u pripravljenim mješavinama, pri čemu nisu zabilježeni bitni temperaturni pomaci egzotermnih kristalizacijskih odziva.There is a concern among the human population due to the global warming caused by greenhouse gas emissions and energy crisis because of depleting of conventional oil reserves. Furthermore, CO2, NOx and particulate matter potentially can cause respiratory and cardiovascular diseases. Biobutanol is an alternative fuel that can be produced from waste biomass, has a good miscibility with diesel fuel and many research studies are performed in order to successfully incorporate biobutanol in the motor fuel market. In this work, the low temperature properties of mixtures of n-butanol and diesel fuel in ratios up to 10 vol. % of n-butanol, without and with polymeric PAMA additives were investigated. One of PAMA additives was synthesized by radical copolymerization and monomer conversion was determined gravimetrically. For all applied polymeric additives the distribution of molecular weights was determined by the gel permeation chromatography (GPC) and composition by the nuclear magnetic resonance (1H NMR). PAMA additive solutions were prepared on the base of proportion of active polymer in the commercial additive solutions, which was determined by the thermogravimetrical analysis (TGA). Distribution of n-paraffins in diesel fuel was obtained by the gas chromatography method (GC) wherein it shown that overall content of n-paraffins equal 23.02 wt. %. The results of standard test methods shows that PAMA additives do not have any effect on the cold filter plugging point of diesel fuel or its mixtures with n-butanol, while pour point is reduced from -18 °C to -24 °C or -30 °C, respectively. Crystallization of paraffins in prepared mixtures was studied by differential scanning calorimetry (DSC); the significant efeects of additives on characteristic temperature values were not recorded