In this work, the path from the cultivation of Arthrospira platensis at an increased concentration of CO2 to the production of bio-oil by hydrothermal liquefaction (HTL) of the grown biomass is realized. The cultivation was carried out in a 90 L photobioreactor at an initial CO2 concentration of 8 vol.% for 15 days. During the cultivation stage, the optical density for microalgae suspension, pH and chemical composition of nutrient medium were monitored. The grown biomass was separated from the nutrient medium with a 100 µm mesh and then subjected to HTL at 330 °C for 1 h. The biomass growth rate was 82 ± 4.1 mg × L−1day−1 and the pH was in the range from 9.08 ± 0.22 to 8.9 ± 0.24. Biochemical and CHNS analyses were applied for the obtained biomass. The contents of carbohydrates, proteins and lipids in the grown biomass were 38.7 ± 0.4 wt.%, 37.4 ± 0.5 wt.% and 3.8 ± 0.4 wt.%, respectively. Bio-oil yield after the HTL procedure was 13.8 wt.%. The bio-oil composition and properties were determined by GH-MS, TLC-PID and ICP-MS techniques. ICP-MS revealed the contents of 51 metals in bio-oil.

Direct study of CO2 capture efficiency during microalgae Arthrospira platensis cultivation at high CO2 concentrations was carried out. Microalgae were grown in a 90 L photobioreactor on Zarrouk's medium prepared with distilled water. Three 15-day experiments were carried out with different initial CO2 concentrations: 1, 5, and 9 vol.%. During the experiments, both the change in the optical density of the microalgae suspension and the direct change in the CO2 concentration in the chamber were measured. The maximum decrease in CO2 concentration due to the growth of microalgae was 0.10 vol.% (CO2)/day in the experiment with an initial CO2 concentration of 5 vol.%. Growth rate of biomass density was 79.4, 76.3, and 48.4 (mg/L)/day at 1, 5, and 9 vol.% CO2 concentrations, respectively. During the experiment with initial CO2 concentrations of 1 and 5 vol.%., pH of the culture medium was increased, but pH was decreased from 9.2 to 8.8 at 9 vol.%. In general, good viability (high quality of biomass and high rate of its growth) of Arthrospira platensis was established at 1 and 5 vol. (CO2)%, while massive death of Arthrospira platensis cells was observed in the experiment with 9 vol. (CO2)%. Biochemical analysis of the resulting biomass revealed a decrease in the content of lipids and proteins with an increase in CO2 concentration.

The work is devoted to the estimation of microalgae resource potential for bio-oil production. We propose a method of climate and infrastructural factors spatial analysis for estimations of resource and the possibility of bio-oil production facilities construction in the study region. The resource potential depends on the area of the territory that can be used to produce biomass as feedstock for biofuel production, and equal to the amount of microalgae biomass that can be obtained on this territory. For the case study we selected the territory of the Republic of Dagestan (Russia) and microalgae Arthrospira platensis and Dunaliella salina. As an infrastructural factors, which may reduce the cost of bio-oil production we considered the following sources of cheap material resources and energy: seawater (as a source of macro- and microelements), geothermal water (as low-temperature heat source), CO2 emissions of cement plants and combined heat and power plants (as carbon source and to reduce CO2 emission). The analyses of these factors using the technology of geoinformation systems allowed to find the most suitable territories for microalgae plant allocation and therefore estimate resource potential for bio-oil production with maximum profit.

Microalgae is a perspective feedstock for producing a wide variety of biofuels and co-products with high added value. An alternative to the traditional technology of biodiesel from algae by the transesterification is the technology of hydrothermal liquefaction (HTL). The article presents the results of promising strains screening and directed cultivation of microalgae for the processing by means of variety of technologies and production of valuable co-products. An algorithm for selecting suitable areas for industrial plantations of algae is presented.

The most useful application of PV solar power in Russia are autonomous power systems in regions with high costs of organic fuels (due to transportation problems). Effective application of PV power needs comprehensive data analysis for solar energy resources, electric and heat load graphs and fuel costs. This paper is devoted to climate and power load data analysis for Russian Far East regions (in connection with PV application) and PV-based power plant mathematical modeling for several locations.