07 Alternative energy sources (geothermal energy)

96/02823 Gasification and pyrolysis - Routes to competitiveelectricity production from biomass in the UKBarker, S. N. Energy Converso Mgmt., Jun.-Aug. 1996, 37, (6), 861-866.Biomass has the potential to become one of the largest sources of renewa­ble, sustainable energy in the UK and many other parts of the EuropeanUnion. However, for biomass to reach its full potential in the electricitymarket generation technologies must be used that maximise the efficiencyof conversion to power. The first generation of these advanced technolo­gies will be expensivebut, as the market expands, should providea route tofully commercial electricity from biomass. The paper examines how theeconomics of advanced biomass power generation technologies mightdevelop from the demonstrationstage to commercialplant and shows howthey can produce competitive electricity in the future.

96/02824 Non-C02-emlttlng renewable energy sources inindia: Paths, realisal:jle potential and requirement of industryrelated forestry patternKumar, S. and Sinha, S. Energy Converso Mgmt., Jun-Sep, 1995,36, (6),885-888.The pattern of the world's energy supply has undergone dramatic changesover the last century and particularly over the last twenty years causingconsiderablestrain to global environment. Particularly in India, the clima­tological effects of burning fossil-fuels make it necessary to develop andincrease the use of non-C0 2-emitting energy sources besides taking up aforestry scheme of specifically developed restrain species. The paper dis­cusses the current states of biomass and renewable eenrgy technologiesthroughoutIndia and their medium-termpotential for carbon-freefuels andelectricity is estimated.

96/02825 Productivity and water use efficiency of sweet sor­ghum (Sorghum Blcolour (L.) Moench) CV. 'Keller' in relation towater regimeFernandez, M. D. and Martinez, M. Biomass & Bioenergy, 1995, 8, (6),401-409.The paper discusses how sweet sorghum (Sorghum bicolor (L.) Moench)has been recognized as an alternative crop for energy purposes.

96/02826 Pyrolysis of blends of biomass with poor coalsPan, Y. G. et al., Fuel, Mar. 1996, 75, (4), 412-418.The paper reports on the pyrolytic behaviour of three different kinds ofsolid fuel and their blends in order to understand and further improve theperformance of fluidized bed gasification of biomass-poor coal blends.Individual feedstocks consisting of pine chips, black coal and waste coaland several biomass-coal blends were pyrolysed in a thermobalance appa­ratus at atmospheric pressure. Experiments were carried out dynamicallyby increasing the temperaturefrom 110 to 900°Cwith a heating rate of 100K min". The data show very poor behaviour of the waste coal comparedwith pine chips and even black coal. Nevertheless, when a minimum of40% of pine chips was blended with 60% waste coal and pyrolysed underthe same conditions, the rate of mass loss increased sharply and was simi­lar to that of black coal.

96/02827 Single rotation vs coppice systems for short-rota­tion intensive culture plantations-Optimality conditions for vol­ume productionRibeiro, C. A. and Betters, D. R. Biomass & Bioenergy, 1995, 8, (6),395-400.Short rotation intensive culture plantations can be managed under a singlerotation or coppice system. The paper shows the optimalityconditions thatmust exist in order to maximize volume production of short rotation cop­pice stands. The results indicate the importance of equating the currentannual increment of the stand to its mean annual increment whether man­aging with a single rotation or a series of coppice rotations over a cycle oftime.

96/02828 Sweet sorghum: A quality raw material for the man-Ufacturing of chemical paper pulpBelayachi, L. and Delmas, M. Biomass & Bioenergy, 1995, 8, (6),411-417.After the extraction of sugar in conditions adaptable to the industrialscale,sweet sorghum bagasse is used for the first time to manufacture chemicalpulp. The quality of the pulp obtained is excellent for the paper industry.

Geothermal Energy

96/02829 Geothermal energyDickson, M. H. and Fanelli, M. (eds) John Wiley & Sons, Baffins Lane,Chichester, West Sussex, P019 1UD, UK, £19.99, Jun. 1995, 232 pp.Geothermal energy, the exploitation of heat from the earth, has immensepotential as a natural energy resource. The contributingauthors of this texteach develop a specific area relating to the possible uses of geothermalenergy and their effects on the community, taking into account the prevail­ing social and economic conditions.

198 Fuel and Energy Abstracts May 1996

96/02830 Heat flow in AlbaniaCermak, V. et al., Geothermics, Feb. 1996, 25, (1), 91-102.As part of a joint geothermal project between Albania and the CzechRepublic, a field expeditionwas organized to Albania in summer 1993 tomeasure temperature profiles in selected boreholes and to collect rock sam­ples to determine their thermal conductivity. Fourteen localities were vis­ited and nine detailed temperature-versus-depth profiles were obtained.These results were completed with numerous industrial temperaturerecordsfrom other deep holes. The regional patterns of temperaturesat 100m depth and of characteristicnear-surface temperaturegradients were con­structed, and the effect of the topography on the subsurface temperaturefield was assessed to calculate a total of 49 heat flow density data.

96/02831 Larderelio-Farinello·Valle Secolo geothermal area:Exergy analysis of the transportation network and of the elec­tric power plantsBettagli, N. and Bidini, G. Geothermics, Feb. 1996, 25, (1), 3-16.An energy-exergy study of the geothermal fluid network in the area ofLarderello-Valle Secolo-Farinello (Tuscany, Italy) which is currentlyundergoing modernization and replacement, is described. This study wascarried out by selling up a stimulation code, which is able to simulate theentire transportation network beginning with the geothermal wells (withrelative connections) through the power plants up to the re-injection of thecondensedwater in the reservoir. In this way, the entire geothermal systemcan be considered as a semi-closed cycle.

96/02832 Modeling studies: The Dachny geothermal reser-voir, Kamchatka, RussiaKiryukhin, A. V. Geothermics, Feb. 1996, 25, (1), 63-90.The spatial distribution of pre-exploitationconditions (i.e. temperature andpressure distribution, liquid and vapour saturations, circulation characteris­tics of high-temperature fluids) in the Dachny field of the Mutnovskyhydrothermal system, obtained using a three-dimensional (3-D) mappingmethod, are revised on the basis of natural-state simulations performedusing the computer code TOUGH2. A 3-D model of the natural-state con­ditions at the Dachnysite was developed.The fine-tuning of the model wasachieved by comparing computer results to the observations made in geo­thermalwells tested druing 1983-88.Also studied was the behaviour of thefield in response to different exploitation scenarios, assuming productionfrom existing and additional welis needed to supply sufficient steam to aproposed 80 MW, power plant.

96/02833 Physicochemical characteristics and leachabilityof scale and sludge from Bulalo geothermal system, PhilippinesPeralta, G. L. et al., Geothermics, Feb. 1996,25, (1), 17-35.Scale and sludge from Bulalo geothermal field, Philippines, have beencharacterized by whole rock analysis, radioactivity counting, size analysis,light microscopy, scanning electron microscopy, and X-ray diffraction.Their leachability was assessed by regulatory leaching procedures and bysequentialextraction. Both scale and sludge consisted mostly of oxides ofSi, AI, and Fe with no radionuclides detected. The scale had 10% S con­tent. Sulphidesand silicates were important phases in both samples havingsize ranges from submicron to 2 mm. Geothermal soils at Bulalo havehigher than normal soil levels of As, S, Cu, Cr, Zn, and Pb but regulatoryleaching tests indicated that these elements are not released. However, thesequential extraction showed that As, Cu, and Zn were leachable underextreme conditions.

96/02834 A simple method to compute hydrogen chlorideabatement in geothermal power plantsPaglianti, A et al., Geothermics, Feb. 1996, 25, (1), 37-62.One of the most important problems affecting geothermal fields is theabatement of hydrogen chloride contained in the vapor phase. If the chlo­ride concentration exceeds a few ppm.., steam scrubbing must be providedin order to prevent corrosionof the gathering system and turbine failure. Insome fields at Larderello, one of the most important geothermal areas inItaly, steam scrubbing is performed by injecting a caustic solution directlyinto the steam pipeline. In particular, the abatement system depends onabsorption with chemical reaction of hydrogen chloride by a sodiumhydroxide solution. The paper describes some of the Larderello powerplant abatement systems and presents analyses of the different solutionsadopted for this purpose.

Solar Energy

96/02835 Analysis of clear hour solar irradiation for sevenCanadian stationsGarrison, J. and Sahami, K. Solar Energy, Dec. 1995, 55, (6), 505·512.Hourly global and diffuse irradiation and corresponding surface meteoro­logical data have been analyzed for the seven Canadian stations atEdmonton, Goose Bay, Montreal, Port Hardy, Resolute, Toronto, and Win­nipeg. The variation of the most probable clear hour values of clearnessindex k., diffuse index kd, direct beam index kb, and Angstrom turbiditycoefficient beta with solar elevation, atmospheric precipitable water, andsnow depth are obtained.