In the work reported here, baker’s yeast (Saccharomyces cerevisiae), used yeast, and apple pomace were used as feed for the production of liquid biofuels in a continuous one-step process under hydrothermal conditions in the presence of excess hydrogen and K2CO3. The biomass conversion experiments were performed in an up-flow reactor under near-critical water conditions (T 330–450 °C, p 20–32 MPa). The products consisted of three phases: an oil-like organic phase, a gaseous phase, and an aqueous phase. Higher concentrations of organic carbon in the process resulted in a higher product yield. The heating value of the organic phase was up to 37.6 MJ kg−1. Liquefaction of yeast without any addition of K2CO3 also resulted in liquid oil, but the quality and the yield of the oil product were lower. The use of K2CO3 catalyst provides significant effect on the apple pomace conversion process. The carbon mass yield ranged from 270 to 400 g kg−1. Our older statement that the reaction of temperature of 400 °C is optimal for the oil yield and quality has been confirmed with the present new experimental results.

The purpose of the work presented here is the production of liquid biofuels from wet organic waste matter in a continuous one-step catalytic process under hydrothermal conditions. The catalytic reaction of wet organic matter at near-critical water conditions (T>300°C, p>22.1MPa) is used to produce a mixture of combustible organics which can be used as liquid biofuel. In order to achieve a good product quality in a continuous one-step process, two catalysts were applied, a homogeneous potassium carbonate catalyst and a heterogeneous ZrO2 catalyst. In addition, the reaction mixture was recirculated. The continuous flow of concentrated waste biomass feed at low flow rates and recirculation of the hot reaction mixture were the most challenging obstacles to overcome. The scale of the plant (0.1l reactor volume) allowed for a variation of the feed, reaction temperature, and recirculation rate in order to optimise the process conditions. Still, the product quantity obtained was sufficient to perform a analytical characterisation. The experimental results confirmed the feasibility of the process. Hydrothermal treatment of waste biomass, after dewatering, resulted in a biocrude oil of high calorific value.

In the work reported here, baker's yeast (Saccharomyces cerevisiae) was used as feed for the production of liquid biofuels in a continuous one-step process under hydrothermal conditions in the presence of excess hydrogen and K2CO3. The yeast conversion experiments were performed in an up-flow reactor under near-critical water conditions (T 330-450 degrees C, p 20-32 MPa). The products consisted of three phases, an oil-like organic phase, a gaseous phase, and an aqueous phase. Higher concentrations of organic carbon in the process resulted in a higher product yield. The heating value of the organic phase was up to 38.6 MJ/kg. Liquefaction of yeast without any addition of K2CO3 also resulted in liquid oil, but the quality and the yield of the oil product were lower. A reaction temperature of 400 degrees C was found to be optimal for the oil yield and quality. (C) 2011 Elsevier Ltd. All rights reserved.