Production of Renewable Hydrocarbons from Thermal Conversion of Abietic Acid and Tall Oil Fatty Acids

Abstract

The primary objective of this study was to investigate the pyrolytic conversion of crude tall oil, a byproduct from the Kraft process in the pulping industry, to hydrocarbon products for use as renewable hydrocarbons and fuels. Abietic acid, the main resin acid in crude tall oil, and tall oil fatty acids, the main distillate fraction of crude tall oil, were pyrolyzed separately using a batch micro reactor at 370, 410, and 450°C for 2 h. The gas and liquid reaction products were identified and quantified using gas chromatography equipped with a flame ionization detector, a thermal conductivity detector, and mass spectrometry. At all temperature regimes, the pyrolysis of abietic acid resulted in the formation of aromatic compounds characterized by up to three benzene rings. While the pyrolysis of tall oil fatty acids at lower temperatures resulted in alkanes and alkenes and negligible amounts of aromatic compounds, higher temperatures promoted the formation of relatively shorter chain alkanes and alkenes and detectable amounts of aromatics. The presence of both CO and CO 2 in the gas fractions suggested that deoxygenation of the initial compounds proceeded through decarbonylation and decarboxylation, but the favored mechanism is dependent upon the structure of the initial substance. This work demonstrates the feasibility of producing renewable hydrocarbons through the pyrolysis of the fatty-acid-rich distillate fraction of crude tall oil.

Thermal and Rheological Properties of Crude Tall Oil for Use in Biodiesel Production

“…The CTO sample had a high amount of linoleic acid (46.24%) as compared to most of the reported results in the literature. Oleic acid was the predominant FFA in CTO in the studies by Jenab et al [2] (47% of total FFA) and Demirbas [35] (39-49%). In accordance with our findings, linoleic acid was the FFA with the highest content in CTO, with 27.6% [15] and 19.1% [13].…”

“…CTO contains a wide range of constituents including light oil, fatty acids (FA), rosin acids (RA), distilled tall oil, pitch residue, and neutral components such as sterols and triglycerides (TGs). The type of wood species (predominantly softwood) used in the pulping process is a factor which determines the yield and composition of CTO, including its fatty and rosin acids content [1,2]. Other factors that affect the properties of CTO include geographical location, type and length of wood storage, hardwood and wood residue usage in chemical pulping, and season of the year [3,4].…”

“…The prospect and potential of CTO for production of value-added, bio-based chemicals and biofuels has been identified by many researchers [2]. CTO has been investigated for production of adhesives [5], paints [6], rubber [7,8], coatings [9,10], biodiesel [11,12], paraffin-rich liquids [13], diesel fuel additives [14], ethylene and propylene [15], etc.…”

The effect of rosin acid on hydrodeoxygenation of fatty acid

“…CTO is often distilled, and depending on the distillation process, different upgraded fractions such as tall oil rosin acid (TOR), distilled tall oil (DTO) and tall oil fatty acid (TOFA) are commercially available as feedstocks for different chemical applications [ 18 , 20 , 21 ]. For instance, compared to TOR, TOFA and DTO fractions containing a higher percentage of fatty acids (71-92 wt%) are generally better feedstocks for production of paraffinic diesel range hydrocarbons [18,20,22] .…”

Reaction pathway analysis in thermal cracking of waste cooking oil to hydrocarbons based on monomolecular lumped kinetics

“…In addition, thermal cracking of Calotropis procera biocrude [17], oleic acid [18], abietic acid and tall oil fatty acids [19] was also studied. The free radical chemistry for thermal cracking of triglycerides to hydrocarbons was proposed by several researchers [10,12,16,[20][21][22][23].…”