BIO-OIL PRODUCTION BY HYDROTHERMAL LIQUEFACTION OF MICROALGAE BIOMASS

Abstract

This article presents a new energy efficient installation created for the process of hydrothermal liquefaction of microalgae with heat recovery. The studying results of the microalgae biomass (Arthrospira platensis) hydrothermal liquefaction at a temperature of 280 °C (holding time is 1 h) are shown. By hydrothermal liquefaction, bio-oil was obtained with much higher content of carbon and lower content of oxygen and nitrogen than the original biomass. Bio-oil was obtained without the use of organic solvents. The output of bio-oil is 29.5%, the heat of combustion is 34.2 MJ / kg. Thermogravimetric analysis was carried out to evaluate the fractional composition of bio-oil. The fraction of bio-oil with evaporation temperature up to 400 °C is about 80 %. The output of the petrol fraction of bio-oil is 26%. The study first held the comparative thermodynamic estimates of energy consumption during hydrothermal liquefaction and drying microalgae biomass, as well as the contribution of thermal energy recovery to increasing the efficiency of hydro-thermal liquefaction. The article presents the results of calculations showing that due to heat recovery, hydrothermal liquefaction has high thermodynamic efficiency and is therefore a very promising way of processing the microalgae biomass for obtaining biofuel. According to the estimates, recuperation can save up to 35% of the thermal energy spent on hydrothermal liquefaction.