• Energy Research

Fast pyrolysis of biomass is a well-known opportunity for sustainable alternative fuel production for transport and energy. However, bio-oils from biomass pyrolysis are viscous, acidic bio-crudes that need further steps of upgrading before being used either as fuels or chemicals. A process that is complementary to bio-oil hydrotreatment or co-processing consists of optimizing and tuning the upstream condensation steps of fast pyrolysis to separate and concentrate selected classes of compounds. This can be implemented by varying the condensation temperatures in a multi-step condensation unit. In this study, fractional condensation of fast pyrolysis vapors from pinewood has been applied to a bubbling fluidized bed reactor of 1 kg h−1 feed. The reactor was operated at 500 °C and connected to a downstream interchangeable condensation unit. Tests were performed using two different condensing layouts: (1) a series of two spray condensers and a tube-in-tube water-jacketed condenser, referred to as an intensive cooler; (2) an electrostatic precipitator and the intensive cooler. Using the first configuration, which is the focus of this study, high boiling point compounds—such as sugars and lignin-derived oligomers—were condensed at higher temperatures in the first stage (100–170 °C), while water-soluble lighter compounds and most of the water was condensed at lower temperatures and thus largely removed from the bio-oil. In the first two condensing stages, the bio-oil water content remained below 7% in mass (and therefore, the oil’s high calorific content reached 22 MJ kg−1) while achieving about 43% liquid yield, compared to 55% from the single-step condensation runs. Results were finally elaborated to perform a preliminary energy assessment of the whole system toward the potential upscaling of this fractional condensation approach. The proposed layout showed a significant potential for the upstream condensation step, simplifying the downstream upgrading stages for alternative fuel production from fast pyrolysis bio-oil.

Nannochloropsis sp. F&M-M24 and Tetraselmis suecica F&M-M33 were cultivated outdoors in Green Wall Panels under nutrient deficiency to stimulate oil synthesis. Under nitrogen deprivation, Nannochloropsis attained average biomass and lipid productivities of 9.9 and 6.5 g m(-2) day(-1), respectively. Starved Tetraselmis cultures achieved a biomass productivity of about 7.6 g m(-2) day(-1) and a lipid productivity of 1.7 g m(-2) day(-1). Lipids represented 39.1% and 68.5% of non-starved and starved Nannochloropsis biomass, respectively. Starvation did not increase lipid content in Tetraselmis biomass. Important differences in lipid classes and in fatty acid composition were observed under the different cultivation conditions for both microalgae.

Micro gas turbines units are reliable and versatile units for on­site combined heat and power production (CHP). Compared to internal combustion engines, CHP units based on micro gas turbines offer several advantages, among which the compactness, the high power­to­weight ratio, lower pollutant emissions and lower maintenance costs. Depending on the specific type of gas turbine, also fuel flexibility could be higher than engines. Within the framework of the EU­Russian Federation FP7 cooperative and specifically the Bioliquids­CHP project, a Garrett GTP 30­67 liquid fuel (diesel) micro gas turbine was adapted to run on alternative first generation biofuels, such as vegetable oil and biodiesel. An in­house test bench for microgasturbine characterization and biofuel testing, capable of accommodating the engine was designed, engineered and built. In this research work, results from experimental measurement on the micro gas turbine are presented. Micro gas turbine performance and main exhaust emissions were measured a various load when feeding biodiesel, vegetable oil (or blending of them) to the engine. Measured exhaust emissions included CO and NOx. The experiences gained on the operation of the micro gas turbine on first generation biofuels will serve as a basis for testing of bio­oil from fast pyrolysis of pine and straw and emulsion between bio­oil and biodiesel in the Bioliquids micro gas turbine. Authors wish to acknowledge the European Commission and FASI for the support given to the present research work, as well as the project coordinator BTG and the project partners. Proceedings of the 19th European Biomass Conference and Exhibition, 6-10 June 2011, Berlin, Germany, pp. 1672-1680

Hydrothermal depolymerization of lignin-rich streams (LRS) from lignocellulosic ethanol was successfully carried out in a lab-scale batch reactors unit. A partial depolymerization into oligomers and monomers was achieved using subcritical water as reaction medium. The influence of temperature (300–350–370 °C) and time (5–10 minutes) was investigated to identify the optimal condition on the monomers yields in the lighter biocrude (BC1) and aqueous phase (AP) fractions, focusing on specific phenolic classes as well as carboxylic acids and alcohols. The effect of base catalyzed reactions (2–4 wt. % of KOH) was compared to the control tests as well as to acid-catalyzed reactions obtained with a biphasic medium of supercritical carbon dioxide (sCO2) and subcritical water. KOH addition resulted in enhanced overall depolymerization without showing a strong influence on the phenolic generation, whereas sCO2 demonstrated higher phenolic selectivity even though no effect was observed on the overall products mass yields. In conclusion, a comparison between two different biocrude collection procedures was carried out in order to understand how the selected chemical extraction mode influences the distribution of compounds between BC1 and AP.

Several substrates were selected in this study and their biogas production potential was assessed by analyzing their physic-chemical characteristics. The parameters used for this assessment were the high yield per hectare and their low cost and diffused availability.

DEVELTAR project was aimed to investigate a device for the removal of tars (cracking) from pyrolysis and gasification gaseous effluents in order to improve their quality as fuel. Tars are condensed and collected by cooling the gaseous effluents than transferred by a wet film of oil to an electricity based technologies with high power and low energy such as microwaves that was extensively examined for this specific purpose. The device developed during the research project was able to use the electrical energy efficiently concentrated towards the disruption of tar molecules, minimizing energy losses through a proper geometrical configuration and setup of process parameters. The main advantage of these technologies is the possibility to concentrate most of the energy on the target molecules avoiding a general increase of the overall energetic level (temperature). The electrical device is not intended for a specific pyrolysis or gasification technology, but as wide-ranging add-on module to be coupled within the gas purification line. The validation at industrial level of the abovementioned technologies, currently known at fundamental research level only, was done at the end of the project. Proceedings of the 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, pp. 1708-1711

Abstract The CarbOn pilot plant is a continuous biomass carbonization system, rated for a capacity of up to 50 kg h−1 and based on open top, downdraft technology, operating in oxidative pyrolysis in the temperature range of 500–650 °C and equivalence ratio (ER) between 0.1 and 0.2. In the reported validation tests, carried out on small size chestnut woodchips, charcoal mass yield in excess of 22.4 ± 0.7 wt% (dry base) has been achieved, with a fixed carbon content higher than 85 wt% (dry base). The fixed carbon yield (FCy) was 18.2 ± 2.2 wt% (dry base), the char carbon yield (CCy) 38.3 ± 1.6 wt% (dry base) and the net energy conversion efficiency to char (e) equal to 41.2 ± 2.2% (wet base). Volume concentration of permanent gases in the pyrolysis vapors and condensable species were also measured before incineration and critically compared against literature data. The organic condensate from oxidative pyrolysis was obtained as 4.9 wt% of the dry biomass, and around 58 wt% of its constituents have been identified; in order of decreasing abundance, the organic fraction of condensate was composed of organic acids, aromatics, furans, anhydrous sugars, phenols, methanol, PAHs, acetaldehyde, ketones. Measured and calculated performance data shows that the pilot unit can produce high quality charcoal, meeting and exceeding the product specifications set by standard EN 1860-2 for BBQ lump charcoal as well as those set forth by international voluntary standards on biochar quality for soil application.