07 Alternative energy sources (bioconversion energy) xylosidase (193 IU g ~ ) activities were concurrently obtained after 5-6 days of fermentation. The higher enzyme activities produced by A. niger KK2 is a significant advantage from the viewpoint of practical saccharification reaction. Cellulases and hemicellulases produced by A. niger KK2 might be applied to pulp and paper industry, feed industry and chemical industry.
04/02871 Pyrolysis of biomass: improved models for simultaneous kinetics and transport of heat, mass and momentum Babu, B. V. and Chaurasia, A. S. Energy Conversion and Management, 2004, 45, (9-10), 1297-1327. Understanding the physical phenomena of pyrolysis and representing them with an appropriate mathematical model is essential in the design of pyrolysis reactors and biomass gasifiers. Description of the chemical processes of pyrolysis is coupled to an unsteady state, one-dimensional, variable property model of transport phenomena, including heat convection, conduction and radiation, volatiles and gas transport by diffusion and convection and m o m e n t u m transfer. In this study, a generalized reference model (Model I) incorporating all the above effects is proposed. This is further improved by proposing two simplified models (Models II and IfI) incorporating additional assumptions. A finite difference pure implicit scheme utilizing a TriDiagonal Matrix Algorithm (TDMA) is employed for solving the heat transfer and mass transfer model equations. A Runge-Kutta fourth order method is used for the chemical kinetics model equations. Simulations are performed considering different geometries of equivalent radius ranging from 0.0001 to 0.017 m and temperatures ranging from 303 to 2800 K. The results obtained using these improved models are in excellent agreement with the experimental data, much better than the agreement with earlier models reported in the literature. The improved validated model, which is best suited for wide ranges of operating conditions, is utilized to investigate the influence of particle size, particle shape, product distribution, conversion time and heat of reaction.
04/02872 Pyrolysis-GC/MS studies of vegetable oils from Macauba fruit Fortes, I. C. P. and Baugh, P. J. Journal of Analytical and Applied Pyrolysis, 2004, 72, (i), 103-Ili. Pyrolysates obtained from vegetable oils of the Macauba tree (Acrocomia sclerocaJTa M.) and from components of the fruit, namely, (1) the endocarp in combination with the mesocarp and (2) the epicarp have been investigated by pyrolysis CG/MS technique under different conditions of gas atmosphere: inert (He) and oxidative [O2/N2 (1:1)]. The differences in pyrolysate profiles and features have also been studied under different pyrolysis conditions (temperature and time). The pyrolysis of the two oils, under inert and oxidative atmospheres, show complex profiles with more than 30 compounds detected. Under the conditions employed, the component oils studied undergo a process of partial pyrolysis to varying extents, generating considerable yields of carboxylic acid, aldehydes, alcohols, alkenes, and alkadienes. Py-GC/ MS technique shown to be a very good analytical tool to study the influence of different atmospheres, pyrolysis time and temperature in the feature of the yield products as well as to obtain some information about the mechanism of pyrolysis of this material under different conditions.
04•02873 Temporal phenomena of hydrogen photobioproduction Dante, R. C. R. C. et al. h~ternational Journal of Hydrogen Energy, 2004, 29, (12), 1219-1226. The photobioproduction of hydrogen through in water alga systems has been studied as a suitable way for clean hydrogen generation from renewable solar energy and renewable bio-sources. There is evidence of such hydrogen path metabolism involving some algae types in stress conditions and this has been reported by several authors. In this paper some results of hydrogen production are shown for different stress conditions carried out in not full aseptic environment stabilized by antibiotics, Chlamydomonas reinhardtii has got resistance to. Oscillations and temporal phenomena of hydrogen production have been observed and studied by means of Fourier analysis. Their nature can be related to the variation of hydrogen production rate usually reflected on the cumulative hydrogen curves by the presence of shoulders or accentuated changes of slope.
04/02874 The Foster Wheeler biomass gasification experience Lampenius, H. IMechE Conference Transactions, 2003, 99-111. This paper comprises a review of development and installation of Foster Wheeler circulating fluidized bed systems for fuel gasification to produce synthesis gas for use in cocombustion power generation. The successful development of the advanced Foster Wheeler circulating fluidized bed (CFB) combustion system subsequently led to the development of the CFB gasification technology in the early 1980s.
Fuel and Energy Abstracts
The driving force, at that time, was the substitution of the high-priced oil and gas with lower cost biomass fuels. Today, the strong emphasis on CO2 reduction and the renewable energy obligation have opened a new market for the gasification technology. Foster Wheeler Energia Oy from Finland has supplied six commercial-scale fluid bed gasifiers with capacities from 15 to 70 MWth based on fuel input. Additionally Foster Wheeler Energia Oy has one 50 MW CFB gasifier project in Belgium in delivery. These plants use biomass and in one case recycled wastes as feedstock. All of the old units are in successful operation today. The experiences of the most recent units, Lahden Lampovoima and Co-renso Oy, are presented. Lahden Lampovoima Oy (LLV) is a Finnish power company producing power and district heat for the city of Lahti. The LLV 70 MW CFB gasifier started its operation in 1998 and it demonstrated on a commercial scale the direct gasification of non-dried biomasses co-fired with 40% recycled fuel (REF). The hot, raw and low calorific syngas gas is directly fired in the existing coal fired boiler, substituting approximately 15% of fuels burned in the PC boiler. The unit for Corenso Oy, Varkaus, Finland, is gasifying the reject from a liquid packaging-board recycling facility. The board contains thin layers of plastic and aluminium that are enriched in the reject. The 40 MWth gasification plant is designed to gasify 18 000 t/a of the plastics and to recover the aluminium, 2100 t/a. Commercial operation was started in autumn 2001. The concept of co-firing biogas in an existing utility boiler, as in the Lahti plant, provides the following main advantages compared to a stand-alone biomass power plant: substantially lower investment costs (the specific investment/Mwe is much lower for a utility size unit than a small stand-alone biomass power plant); higher power output/biofuel input, a utility cycle efficiency vs a biomass power plant efficiency; low operational cost no extra personnel needed; allows for substitution of gas and coal with bio waste fuels. The gasification of biomass, and co-combustion of the syngas in the existing coal-fired boiler also offers such advantages as: the biomass CO2 benefit, decreased SO2 and NO× emissions and an efficient way to use local biomasses and recycled refuse fuels. Also, only small modifications are required at the utility boiler, and possible disturbances in the gasifier do not shut down the whole power plant. The experiences from this concept were excellent. The availability of the plant was good; and the results, with regard to the product gas quality, gasifier bottom ash, main boiler filter ash, and the emissions after the main boiler fulfil expectations. Foster Wheeler Energia Oy is further developing the gasification process towards increased use of classified industrial and municipal waste fuels. The content of alkaline, chlorine and heavy metals in the waste fuels requires a cleaning of the product gas before being fired in the utility boiler. The cleaning process involves gas cooling and filtration. The aim is to achieve a cost-effective reliable process providing a gas clean enough to enable firing on an utility power boiler. Gas purity required for gas turbines or engines is not targeted as it would require a very expensive complex system. The gas cleaning process was tested in Foster Wheeler Energia Oy's R & D centre, where a 3 MW pilot CFB gasifier is equipped with gas cooler and gas filtration equipment.
04/02875 Thermal regulation of building-integrated photovoltaics using phase change materials Huang, M. J. et al. International Journal of Heat and Mass Transfer, 2004, 47, (12-13), 2715-2733. Elevated operating temperatures reduce the efficiency of photovoltaic devices. The use of a phase change material to produce a moderate building integrated photovoltaic temperature rise has been investigated by experiments and numerical simulations. Experimental data are used to validate the previously developed two-dimensional finite volume heat transfer model conjugated hydrodynamically to solve the NavierStokes and energy equations. A parametric study of a design application is also reported. Temperatures, velocity fields and vortex formation within the system were predicted for a variety of configurations using the experimentally validated numerical model. Temperature distributions predicted for different insolation and ambient temperatures at the photovoltaic surface show that the moderation of temperature achieved can lead to significant improvements in the operational efficiency of photovoltaic facades.
04/02876 Tree growth, biomass, allometry and nutrient distribution in Gmelina arborea stands grown in red iateritic soils of Central India Swamy, S. L. et al. Biomass and Bioenergy, 2004, 26, (4), 305-317. A chronosequence of Gmelina arborea Roxb. stands ranging from 1 to 6 years old was measured to document changes in growth, biomass and nutrient (N, P and K) contents for three red lateritic sites in Chhattisgarh, India. The stand's density, survival and growth parameters (DBH, total height, crown diameter and number of branches) varied significantly with age and site. The number of stems was highest (789 trees/ha) in a 1-year-old plantation at site 3 (Kusumi) and lowest (724 trees/ha) in a 6-year-old stand at site 2 (Anandgoan). Allometric equations for stem wood, branches, leaves and roots to tree diameter at breast height were developed to estimate above ground and