Effect of hydrogen gas pressure on biofuel characteristics in hydrogenation reaction of non-oxygenated fraction of bio-oil

Dijan Supramono, Elizabeth Verdiana Listiono, Mohammad Nasikin

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Citations (Scopus)


The pyrolysis of biomass and plastic waste to biofuel is recognized as an effective solution to the energy crisis and waste issue both of which are perceived as the two most urgently solved problems now by Indonesia. Co-pyrolysis of equal weights of corncob and polypropylene plastic at low heating rate has been able to produce a non-polar bio-oil with similar characteristics to those of commercial diesel fuel. Bio-oil obtained from co-pyrolysis spontaneously separates non-polar from polar fractions with the former being larger volume fraction than the latter. This non-polar fraction has branching index of 1.22. However, this non-polar fraction contains 5.39% of vinyl group which is undesired in diesel machine high-temperature combustion due to its tendency to smoke formation and increased the ignition delay time. Hydrogenation reaction of the non-polar bio-oil is expected to reduce the vinyl content to allow its use as biofuel. Low content of vinylic carbon allows low catalyst loading in the reaction and therefore the reactor can be designed as liquid-phase dominated one. The solubility of H2 gas in liquid phase is one of the important controlling variables in the hydrogenation reaction and highly affected by H2 gas pressure in the gas convection within the liquid phase. The present work investigated the effects of H2 gas pressure on characteristics of biofuel. The pressure was varied from 4 to 10 bars. The hydrogenation process was conducted in a 300 mL autoclave reactor equipped with down-flow 45o pitched blade turbine impeller. This type of impeller allows entrainment, dispersion and inducing solubility of H2 gas in bio-oil. Catalyst of Ni/γ-Al2O3 was used to obtain high conversion of hydrogenation reaction. The biofuel products and commercial diesel fuel were characterized by FT-IR, H-NMR, and LC-MS to acquire information of carbon chains, vinyl contents, branching indices, and molecular weight distribution. This characterization can analyse the similarities between non-polar bio-oil and commercial diesel fuel to verify the use of the biofuels as diesel fuel alternative. The present work shows that compared to commercial diesel, biofuels obtained from hydrogenation at different pressures had methyl contents about twice and methylene contents about a quarter than those in diesel fuel and at pressures of 8 and 10 bars, all vinyl was removed from biofuels. The branching indices in biofuels were still higher three to four folds than that in diesel fuel. Compared to diesel fuel, biofuels had molecular weights relatively lower than that of diesel fuel and had HHVs similar to that of diesel fuel.

Original languageEnglish
Title of host publicationProceedings of the 5th International Symposium on Applied Chemistry 2019
EditorsOsi Arutanti, Ahmad Randy, Muhammad Arifuddin Fitriady
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735419223
Publication statusPublished - 19 Nov 2019
Event5th International Symposium on Applied Chemistry 2019, ISAC 2019 - Bumi Serpong Dama (BSD) City, Tangerang, Indonesia
Duration: 23 Oct 201924 Oct 2019

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Conference5th International Symposium on Applied Chemistry 2019, ISAC 2019
CityBumi Serpong Dama (BSD) City, Tangerang


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