The exploitation of biomass for building space heating in Greece: Energy, environmental and economic considerations

The exploitation of forest and agricultural biomass residues for energy production may offer significant advantages to the energy policy of the relevant country, but it strongly depends on a number of financial, technological and political factors. The work in hand focuses on the investigation of the energy, environmental and financial benefits, resulting from the exploitation of forest and agricultural biomass residues, fully substituting the conventional fuel (diesel oil) for building space heating in Greece. For this investigation, the energy needs of a representative building are determined using the EnergyPlus software, assuming that the building is located across the various climate zones of Greece. Based on the resulting thermal energy needs, the primary energy consumption and the corresponding emissions are determined, while an elementary fiscal analysis is also performed. The results show that significant financial benefits for the end-user are associated with the substitution examined, even though increased emissions and primary energy consumption have been derived

Augmented Leaching Pretreatments for Forest Wood Waste and Their Effect on Ash Composition and the Lignocellulosic Network

By augmenting conventional leaching technologies for the removal of ash constituents from lignocellulosic waste residues, a cleaner and energy efficient solution can be provided for critical industrial problems such as biomass feeding, defluidization, and reactor corrosion. It has been found that not only are inorganic constituents (ash) effectively removed by coupling a physicochemical technology with conventional leaching but also the intermolecular interactions within the lignocellulosic matrix can be modified, as shown by a variable crystallinity index (powder X-ray diffraction) without the loss of physical bonding (Fourier-transform infrared spectroscopy). Ultimately, this allowed for a greater thermochemical transformation of cellulose, hemicellulose, and lignin for all technologies used: conventional leaching, indirect/directed ultrasound, and microwave irradiation. However, the use of directed ultrasound was found to be the standout, energy efficient technology (8.6 kJ/g) to radically improve the thermochemical transformation of wood waste, especially in the reduction of fixed carbon at high temperatures. It was also found to be efficient at removing vital eutectic mixture causing elements, including Si, which is known to be notoriously difficult to remove via leaching. In comparison, hot plate leaching and microwave irradiation use 39 and 116 times more energy, respectively. The integration of this technology into the energy production sector will prove vital in the future due to its scalability, as compared with microwave alternatives, which are currently not suitable for large scale operations. Additionally, the residence time required for directed ultrasound was found to be negligible as compared to the various other physicochemical techniques, 0.1 h opposed to 4 h

Hyperspectral Sensing Techniques Applied to Bio-masses Characterization: The Olive Husk Case

Olive husk (OH) quality, in respect of constituting particles characteristics (olive stones and pulp residues as result after pressing), represents an important issue. OH particles size class distribution and composition play, in fact, an important role for OH utilization as: organic amendment, bio-mass, food ingredient, plastic filler, abrasive, raw material in the cosmetic sector, dietary animal supplementation, etc. . OH is characterised by a strong variability according to olive characteristics and olive oil production process. Actually it does not exist any strategy able to quantify OH chemical-physical attributes versus its correct utilisation adopting simple, efficient and low costs analytical tools. Furthermore the possibility to perform its continuous monitoring, without any samples collection and analysis at laboratory scale, could strongly enhance OH utilization, with a great economic and environmental benefits. In this paper an analytical approach, based on HyperSpectral Imaging (HSI) is presented. HSI allows to perform, also on-line, a full quantification of OH characteristics in order to qualify this product for its further re-use, with particular reference as bio-mass. HSI was applied to different samples of OH, characterized by different moisture, different residual pulp content and different size class distributions. Results are presented and critically evaluated. © 2011 IFIP International Federation for Information Processing

Fe catalysis for lignocellulosic biomass conversion to fuels and materials via thermochemical processes

Recently, international research is aiming at developing gasification and pyrolysis processes for the cost-effective thermochemical conversion of non-food biomass to biofuels. Gasification produces a mixture of carbon monoxide and hydrogen, known as syngas. Pyrolysis produces a liquid bio-oil. Both syngas and bio-oil can be used directly or can be converted to clean fuels and other valuable chemicals. Catalysis is central to achieving this aim. This study presents results from lignocellulosic biomass pyrolysis, air and steam gasification in the presence of Fe. Noncatalytic and catalytic pyrolysis and gasification experiments were carried out at temperature range of T = 500-760 °C under an inert helium atmosphere for pyrolysis and at T = 750-1050 °C with air and steam as the gasification agents for gasification. The effect of temperature (°C), heating rate (°C/min), gasification medium (steam or air), air ratio (λ), steam to biomass ratio (S/B) as well as the catalytic effect of Fe naturally dispersed in the biomass char were studied. The influence of the iron traces originated from the native biomass and ending up in the char residue is mostly studied. Moreover, experiments were performed and results discussed of Fe residues utilization mixed with the bed material to act as catalyst for the conversion of biomass. The results of the performed study showed that olive kernel pyrolytic char is highly reactive comparing to cellulosic biomass char, due to its porous structure, increased surface area and ash content rich in metals. In combination, the presence of metals in olive kernel ash (especially Fe metal) can play an active catalytic role in tar cracking. Additional results have also shown that the addition of Fe residue as in bed catalyst for upgrading non edible residual biomass, favorises the production of H 2 rich gas (syngas) due to Fe pronounced catalytic activity. © 2012 Elsevier B.V

Investigation of agricultural and animal wastes in Greece and their allocation to potential application for energy production

Agricultural and animal wastes constitute a high proportion of biomass in Greece, and are able to play an important role towards the satisfaction of heat and/or energy and related material supply, with respect to the environmental protection targets. This paper describes pyrolysis, gasification and combustion, as a potential agricultural and animal waste exploitation method, and presents a comparison between those treatments when utilized as a source for renewable energy. The aim of the present work was to strengthen the interest in agricultural and animal waste potential for energy production in Greece, through a methodology for the feasibility of utilization of those kinds of wastes as renewable energy resources. A combination of technical, economic and environmental issues is presented here, and focus on the benefits that thermochemical conversion is able to offer, either in investigation or in future technological application for alternative exploitation methods of animal and agricultural wastes. © 2006 Elsevier Ltd. All rights reserved

Investigation of agricultural and animal wastes in Greece and their allocation to potential application for energy production

Agricultural and animal wastes constitute a high proportion of biomass in Greece, and are able to play an important role towards the satisfaction of heat and/or energy and related material supply, with respect to the environmental protection targets. This paper describes pyrolysis, gasification and combustion, as a potential agricultural and animal waste exploitation method, and presents a comparison between those treatments when utilized as a source for renewable energy. The aim of the present work was to strengthen the interest in agricultural and animal waste potential for energy production in Greece, through a methodology for the feasibility of utilization of those kinds of wastes as renewable energy resources. A combination of technical, economic and environmental issues is presented here, and focus on the benefits that thermochemical conversion is able to offer, either in investigation or in future technological application for alternative exploitation methods of animal and agricultural wastes.Agricultural Animal Wastes Energy Environment Greece

Activated carbon from olive kernels in a two-stage process: industrial improvement

Activated carbons have been prepared from olive kernels and their adsorptive characteristics were investigated. A two stage process of pyrolysis-activation has been tested in two scales: (a) laboratory scale pyrolysis and chemical activation with KOH and (b) pilot/bench scale pyrolysis and physical activation with H 2 O-CO 2 . In the second case, olive kernels were first pyrolysed at 800 °C, during 45 min under an inert atmosphere in an industrial pyrolyser with a throughput of 1 t/h (Compact Power Ltd., Bristol, UK). The resulting chars were subsequently activated with steam and carbon dioxide mixtures at 970 °C in a batch pilot monohearth reactor at NESA facility (Louvain-la Neuve, Belgium). The active carbons obtained from both scales were characterized by N 2 adsorption at 77 K, methyl-blue adsorption (MB adsorption) at room temperature and SEM analysis. Surface area and MB adsorption were found to increase with the degree of burn-off. The maximum BET surface area was found to be around 1000-1200 m 2 /g for active carbons produced at industrial scale with physical activation, and 3049 m 2 /g for active carbons produced at laboratory with KOH activation. The pores of the produced carbons were composed of micropores at the early stages of activation and both micropores and mesopores at the late stages. Methylene blue removal capacity appeared to be comparable to that of commercial carbons and even higher at high degrees of activation. © 2007 Elsevier Ltd. All rights reserved

Rapeseed residues utilization for energy and 2nd generation biofuels

Lignocellulosic biomass is an interesting and necessary enlargement of the biomass used for the production of renewable biofuels. It is expected that second generation biofuels are more energy efficient than the ones of first generation, as a substrate that is able to completely transformed into energy. The present study is part of a research program aiming at the integrated utilization of rapeseed suitable to Greek conditions for biodiesel production and parallel use of its solid residues for energy and second generation biofuels production. In that context, fast pyrolysis at high temperature and fixed bed air gasification of the rapeseed residues were studied. Thermogravimetric analysis and kinetic study were also carried out. The obtained results indicated that high temperature pyrolysis could produces higher yields of syngas and hydrogen production comparing to air fixed bed gasification. © 2007 Elsevier Ltd. All rights reserved