(77e) Use of Co-Solvent on the Financial Viability Ofbio-Crude Production By HTL.

Hydrothermal Liquefaction (HTL) is a promising technology to produce biocrude from microalgal biomass that has captured gaseous CO2. However, several problems of this technology must still be solved to make it economically and technically feasible. One of the main problems in the financial viability of the HTL process is the low yield obtained when only water is used as a solvent, with results close to or lower than 30 wt%. This, in turn, increases the production cost to over 120 USD/BBL. In recent years, some authors have focused their efforts on increasing biocrude production through the extensive use of organic solvents, without considering the effects on economic viability. The present work evaluated the financial effect of using acetone as an organic co-solvent, finding that high acetone contents increased operating costs of the process, mainly due to losses in its handling and recovery. In contrast, very low acetone contents had very little effect on the biocrude yield. It was possible to establish that concentrations close to 5 wt% of acetone, mixed with water, resulted in a yield of about 60 wt% and a production cost of 50 USD/BBL of biocrude, with an energetic densification of 30.25 MJ/kg and 8.60∘ API, classifying it as heavy crude, which makes it necessary to include refining processes for heteroatom removal. Chemical characterization of biocrude revealed a high content of nitrogenous compounds (23.6 wt%) and oxygenated compounds (10.7 wt%), which have to be removed for the subsequent production of commercial liquid fuels. It is concluded that the use of a water-acetone mixture allows for obtaining positive operating profits, which helps to the high capital costs involved in this type of technology, making it more financially comparable with the conventional petroleum industry. Figure 1 shows the effect of acetone content on the operating profit.

This innovation made it possible to obtain the first patent in the Department of Chemical Engineering and the second international patent in the Faculty of Engineering of the University of Antioquia, obtained from the hand of Cementos Argos in the United States "SOLVOTHERMAL LIQUEFACTION PROCESS FROM BIOMASS FOR BIOCRUDE PRODUCTION US 11,814,586 B2" [2] This patent establishes not only the technical but also the financial and environmental conditions that minimize production costs in obtaining a biocrude with estimated production costs of 45 – 50 USD/BBL, with characteristics similar to crude oil, from renewable sources such as biomass.

Cementos Argos, the main cement company in Colombia and fourth in Latin America, has a pilot plant for the production of microalgae from the real gases of cement production, at the Cement Plant in Cartagena Colombia, like strategy to reduce the environmental impact, interested in valuing the microalgae obtained in the capture of CO₂, associated with the Ministry of Science and Technology in Colombia (MinCiencias), supported the construction of a pre-commercial hydrothermal liquefaction system near microalgae pilot plant shown in Figure 2, which seeks the production of biocrude oil in sufficient quantities for its incorporation into conventional refining systems by the hand of the oil refining, production and exploration company in Colombia Ecopetrol through the Colombian Petroleum Institute.

This development aims to establish the technical, financial and environmental conditions that allow the incorporation of biocrudes in conventional refining systems based on hydrothermal liquefaction technology, initially validated with microalgae, however it does not limit its scope only to microalgae since forest and agro-industrial waste, municipal waste residual among others could be valorized.

[1] D. Ocampo, L. A. Ríos, G. J. Vargas, and A. G. Elkin, “Effects of the use of acetone as co-solvent on the financial viability of bio-crude production by hydrothermal liquefaction of CO 2 captured by microalgae,” J. CO2 Util., vol. 89, no. 52, pp. 0–6, 2024, doi: 10.1016/j.jcou.2024.102960.

[2] D. Ocampo, L. A. Rios, E. Gómez, and G. J. Vargas, “Solvothermal Liquefaction Process For Producing Bio-Crude From Biomass,” US011814586B2, 2023.