Diesel production from lignocellulosic feed: the bioCRACK process.

The bioCRACK process is a promising technology for the production of second generation biofuels. During this process, biomass is pyrolized in vacuum gas oil and converted into gaseous, liquid and solid products. In cooperation with the Graz University of Technology, the liquid phase pyrolysis process was investigated by BDI - BioEnergy International AG at an industrial pilot plant, fully integrated in the OMV refinery in Vienna/Schwechat. The influence of various biogenous feedstocks and the influence of the temperature on the product distribution in the temperature range of 350°C to 390°C was studied. It was shown that the temperature has a major impact on the product formation. With rising temperature, the fraction of liquid products, namely liquid CHO-products, reaction water and hydrocarbons, increases and the fraction of biochar decreases. At 390°C, 39.8 wt% of biogenous carbon was transferred into a crude hydrocarbon fractions. The type of lignocellulosic feedstock has a minor impact on the process. The biomass liquefaction concept of the bioCRACK process was in pilot scale compatible with oil refinery processes.

Electrochemical oxidation of wastewater - opportunities and drawbacks.

Electrochemical oxidation by means of boron-doped diamond (BDD) anodes generates a very efficient oxidizing environment by forming hydroxyl radicals, providing effective water purification for elimination of persistent pollutants. In this project the degradation rates of organic and inorganic substances are investigated. Experiments were performed in laboratory and pilot scale with synthetic and industrial wastewaters. Performance parameters were evaluated in terms of total organic carbon/chemical oxygen demand (COD) removal, specific energy consumption and current efficiency. The integration of this advanced oxidation technology combined with conventional technology was then applied in a wastewater treatment concept of landfill leachate. The raw leachate with a low biochemical oxygen demand/COD ratio was electrochemically oxidized to prepare the purified leachate for discharge into a sewage system or a receiving water body. The cost estimation regarding operation and capital costs addresses the economics for the treatment of heavily polluted effluents.

Formation of liquid and solid products from liquid phase pyrolysis.

The aim of the present work was to improve the C:O ratio in biomass by preserving the lignin macrostructure of lignocellulosic feed. The intention of liquid phase pyrolysis is to liquefy biomass and prepare biomass for further upgrading steps like hydrogenation and deoxygenation. Pyrolysis was carried out in a non-aqueous liquid phase heat carrier. The process was carried out in a semi-batch reaction vessel under isothermal conditions at T=350°C, supported by a quench to stop reactions instantaneously in order to observe formation of solid intermediates. This pyrolysis system enables the observation of liquid and solid product formation. Transformation of biomass into biochar was analyzed by infrared spectroscopy and elemental analysis. Stable lignin structure throughout the whole transformation was confirmed. It was shown that the lignin frame in wood remains without substantial loss, while the major amount of carbohydrates is pyrolyzed during liquid phase pyrolysis at T=350°C.

Conversion of sewage sludge into lipids by Lipomyces starkeyi for biodiesel production.

The potential of accumulation of lipids by Lipomyces starkeyi when grown on sewage sludge was assessed. On a synthetic medium, accumulation of lipids strongly depended on the C/N ratio. The highest content of lipids was measured at a C/N-ratio of 150 with 68% lipids of the dry matter while at a C/N-ratio of 60 only 40% were accumulated. Within a pH range from 5.0 to 7.5 the highest lipid accumulation was found at pH 5.0 while the highest yield per litre was pH 6.5. Although sewage sludge had no inhibitory effects on growth or accumulation on L. starkeyi when added to synthetic medium, there was no significant growth on untreated sewage sludge. However, pretreatment of sludge by alkaline or acid hydrolysis, thermal or ultrasonic treatment lead to accumulation of lipids by L. starkeyi with highest values of 1 g L(-1) obtained with ultrasound pre-treatment. Based on the content of free fatty acids and phosphorus, lipids accumulated from sewage sludge could serve as a substrate for the production of biodiesel.