A simplified statistical model was developed to simulate the combustion behavior in wood pellets burners based on the eddy dissipation concept and the assumption that the turbulence to some extents can be treated in a similar way in both the larger scales and the smaller scales. The combustion system was divided into several macroscopic sub-volumes which were characterized by plug flow function with axial diffusion that helps to bridge the geometry with the mixing status and describe the dissipation of turbulence by means of digital filter. Initially a time series of fuel-air mixture was defined according to feedstock and air supply in burner and then successively modified in the following sub-volumes based on the predefined function and additional air. With favor of mass and energy balance the final gas composition can be approximately distributed by water gas equilibrium. After involved the system response of gas analysis instrumentation, the modelled results were compared with experimental tests in two commercialized types of pellet burners, named gasification type and combustion type respectively. The model predicted reasonably the over-all behavior of domestic-scale pellet burners on the mean value and standard deviation of gas compositions, especially the behavior of CO2 and O2 in both cases. The CO emission was simulated unstably but within an acceptable range. This model can be used as an on-line predictor in combustion control systems and may thus serve as a tool for fast-response combustion control. 

The current investigation focused on obtaining experimental results on properties of different woody and oily biomasses during lab-scale storage. During large-scale storage of vegetable oils, biodiesel and woody biomasses, physical, biological and chemical processes lead to deterioration of the fuel, self-heating and in some cases to self-ignition. The heat released from the different biomass samples was measured by isothermal calorimetry, with the purpose to assess the biomass suitability for storage. The highest thermal output came from the boiled linseed oil, but also from olive oil. Wood pellets give rise to different levels of thermal output during storage and the levels depend on the moisture content, ambient gas media but not the resin content. The total energy release, as well as the peak value for the thermal power development in the individual ampoules, was limited by the amount of oxygen present. In spite of this, chemical heat release rates well exceeding 50 W/tonne were registered already at a sample temperature of 50 °C. The results are intended to be useful when planning for the large-scale use of different biomasses, leading to the need of storage. By measuring the heat released from different biomass samples, the biomass suitability for storage can be assessed. 

The use of solid biomass is already dominant among RES not only in the South Baltic but in the European Federation as a whole and is expected to grow. With this, not only emissions from combustion but also emissions from storage and handling are apt to increase.The storage and handling of biomass is, however, not free from risks and problems.The current report discusses some of the risks associated with the large-scale handling and storage of biomass with special emphasis on the processes occurring during storage and the mechanisms behind auto-ignition.The report contains experimental results and information on different biomasses and their characteristics, with focus on the characteristics affecting the storage and handling properties. It is intended to be useful when planning for the use of different biomasses, leading to the need of storage.

This paper analyze the benefits of the use of bioenergy, solar thermal and wind energy in a flexible energy system to increase the share of renewable sources (RES) in primary energy supply, reduce primary energy consumption (PEC) and ensure power supply security in Inland Norway, and Norway at large. Firstly, the Inland reference energy system was built and validated using the EnergyPLAN system analysis tool based on the year 2009. Two alternative systems (scenarios), mainly of bio-heat and heat pumps in individual and district heating systems were then constructed and compared with the reference system using EnergyPLAN. The quality of a given energy system can be best described by its PEC, RES, emission levels and socio-economic costs. The result shows that it is plausible to improve the quality of the Inland energy system by optimal resource assortment in the energy mix. Integrated use of bin-heat and heat pumps in individual and district heating systems, as a replacement for direct electric heaters would reduce PEC and socio-economic costs considerably more than intensive bio-heating deployment alone, thereby increasing total domestic green electricity generation. The ability to integrate wind power and its value in the Inland energy system is more reflected by reducing imports of electricity during peak demand periods in winter, as wind power availability in the region is significant as opposed to the low precipitation during these periods. In addition, increasing wind energy penetration helps to limit biomass consumption in a district heating system built on heat pumps and bio-heat boilers. (C) 2014 Elsevier Ltd. All rights reserved.

The technological needs to achieve CO2 neutrality during glass manufacturing have been investigated by theoretical calculations on energy balances and experimental investigations on batch reactivity and fining efficiency. The concept is based on the assumption of utilization of woody bio fuel combustion directly over the batch blanket and glass melt bath for heating the glass furnace. Energy balance calculations were made for a “hot top”, 50 tonnes per day continuous furnace. Furthermore, elimination of the chemically bound CO2 in the glass batch has been considered by investigating the possible substitution of the batch carbonates by other compounds not bearing chemically bound CO2. Compounds not emitting oxides of carbon, nitrogen or sulphur were considered as candidate batch components. Studies on the effect of batch melting and fining indicate a beneficial effect on energy efficiency and melting rate when using carbonate substitutes. It is concluded that the combustion concept is theoretically fully possible for glass tank application. The substitution of batch carbonates by non carbon compounds is questionable from an environmental point view since the alternatives are expected to be synthesized by routes emitting CO2.