One of the conventional kraft pulp mills produce crude tall oil which is a mixture of free fatty acids, resin acids, sterols, terpenoid compounds, and many others. This study is devoted to the issue of direct transformation of crude tall oil in a mixture with straight-run atmospheric gas oil to liquid fuels using three different commercial hydrotreating catalysts. Diesel fuel production is an alternative to incineration of these materials. High catalytic activity was achieved for all tested catalysts in temperature range 360–380°C, under 5.5？MPa hydrogen pressure and ratio H2/feedstock 500–1000 l/l. Crude tall oil can be converted to diesel oil component via simultaneous refining with straight-run atmospheric gas oil on NiMo/Al2O3 and NiW/Al2O3-zeolite catalysts. All tested catalysts had very good hydrodenitrogenation activity and high liquid yield were at tested conditions. 1. Introduction One of the modes of reducing the share of green house gases (GHG) emissions at energy production lies in the utilization of biomass and wastes. In the initial step, the known technological processes and feedstock commonly applied in foodstuff processing industry were utilized to produce first generation biocomponents. The use of fatty acid esters, bioalcohol, and ETBE is common at present. First-generation biocomponents are usually more expensive when compared to petroleum-based fuels. Competition with foodstuff production is questionable as well. The actual system based on indicative targets of reaching the total energy content or volume of biocomponents does not support priorities of biocomponents utilization with low-cost GHG emission decrease. The regulatory mechanisms should be stipulated in a way that allow finds a possible reduction in the GHG emission for various biofuels and foodstuffs. Biofuels should be supported through an efficiency increase of current biocomponents and development of new improved procedures. The regulatory mechanism should not act as a barrier for new biofuel types. One of the possible solutions is represented by the introduction of second generation biocomponents originated from wastes. Crude tall oil (CTO)  is a byproduct of paper production from coniferous wood by the Kraft pulping process. As an average, 20–30？kg tall oil/ton wood is produced. It contains 30–50% wt. of free fatty (mainly oleic and linolic) acids, 40–60% of rosin acids (abietic and pimaric acids), and 10–15% of unsaponifiables containing 2–4% of sterols, fatty alcohols, phenols and hydrocarbons. Free fatty acids (FFAs) and rosin acids (RAs) can be separated by
T. Kocsisová, J. Cvengro？, and J. Luti？an, “High-temperature esterification of fatty acids with methanol at ambient pressure,” European Journal of Lipid Science and Technology, vol. 107, no. 2, pp. 87–92, 2005.
I. Kubi？ková and D. Kubi？ka, “Utilization of triglycerides and related feedstocks for production of clean hydrocarbon fuels and petrochemicals: a review,” Waste and Biomass Valorization, vol. 1, no. 3, pp. 293–308, 2010.
J. Wildschut, F. H. Mahfud, R. H. Venderbosch, and H. J. Heeres, “Hydrotreatment of fast pyrolysis oil using heterogeneous noble-metal catalysts,” Industrial and Engineering Chemistry Research, vol. 48, no. 23, pp. 10324–10334, 2009.
S. Lestari, P. M？ki-Arvela, I. Simakova, J. Beltramini, G. Q. M. Lu, and D. Y. Murzin, “Catalytic deoxygenation of stearic acid and palmitic acid in semibatch mode,” Catalysis Letters, vol. 130, no. 1-2, pp. 48–51, 2009.
B. Donnis, R. G. Egeberg, P. Blom, and K. G. Knudsen, “Hydroprocessing of bio-oils and oxygenates to hydrocarbons. Understanding the reaction routes,” Topics in Catalysis, vol. 52, no. 3, pp. 229–240, 2009.
S. Bezergianni, A. Dimitriadis, A. Kalogianni, and P. A. Pilavachi, “Hydrotreating of waste cooking oil for biodiesel production. Part I: effect of temperature on product yields and heteroatom removal,” Bioresource Technology, vol. 101, no. 17, pp. 6651–6656, 2010.
S. Bezergianni, A. Dimitriadis, T. Sfetsas, and A. Kalogianni, “Hydrotreating of waste cooking oil for biodiesel production. Part II: effect of temperature on hydrocarbon composition,” Bioresource Technology, vol. 101, no. 19, pp. 7658–7660, 2010.
R. Tiwari, B. S. Rana, R. Kumar, et al., “Hydrotreating and hydrocracking catalysts for processing of waste soya-oil and refinery-oil mixtures,” Catalysis Communications, vol. 12, no. 6, pp. 559–562, 2011.