07 Alternative energy sources (geothermal energy)

95/04867 Kinetic rvaluatlon of an anarroblc fluldiaed-bed reactor treating alaughtarhouae wastewater Borja, R. et al, Bioreso~ce TechnoL, 1995.52, (2), 163-167. An anaerobic fluid&d-bed reactor for tcwater WY modcllcd as a continuous- K

urification of slaughterhouse was- 0~. completely-rmxcd homogcnc-

ous microbial system. The average microbml residence *tic in the reactor was defined in terms of conventIonal sludge-retention-tune. The observed biomass yield in the reactor decreased with increasing sludge-retcntion- time. The specific methane production rate observed was a linear function of the spcclfic substrate-utilisation rate.

95104868 dlgeatlon

Modelllng of gas pressure effects on anaeroblc

Vavilin, V. A. et al., Bioresource TechnoL, 1995,52, (l), 2.5-32. The model of anaerobic digestion described earlier by the authors was used for analysis of a pressure change as a method of avoiding a gas component toxicity. The model. calibrated for laboratory-scale reactors, showed that an increase in pressure reduced ammonia inhibition during simulated cat- tle-manure digestion. A decrease in pressure reduced free hydrogen sulphidc inhibition during a sulphatc overload of an anaerobic digestion of a synthetic feedstock.

Geothermal Energy

Z:75 Approaches to the modelllng of HDR reaervolra: A

Willis-Richards, J. and Wallroth, T. 307-332.

Geotkrm&, Jun. 1995, 24, (3),

A classification of HDR models by their representation of the reservoir geometry is presented together with the ‘building-block’ sub-proccsacs which embody much of the coupled physics necessary for HDR modcllmg. A number of current modclling approach= arc reviewed The need for integrating stimulation and circulation models is identified. The aced for a

p though not necessarily fully c licit, representation of the reservoir

acture geometry is necessary as a vc lclc to express the coupled physics. “g. Limitations on the computational tractability of explicit network models, when strongly coupled physics arc added, suggests the types of model that may hold the most promise for future work.

95lQ4876 Aaaeaament of HDR reaervolr ??timulatlon and per- formance ualn

B Willis-Richards. . almple stochastic models

Georhermics. Jun. 1995, 24. (3). 385-402. Experience in developing and c&dating HDR r&&oirs 81 Roscmanowcs in Cornwall. UK. and more reccntlv a1 Soultz-Sous-Forcts in Alsacc. France, su&& ihat the natural fra&rc system controls fluid flow and that artificial fractures arc relatively unimportant. Two simple models, based on standard analytic solutions for the mechanical bchaviour of cracks combined with a &nplc representation of the frictional properties of fracture surfaces? have been developed. The models describe the stimula- tion and circulahon of HDR reservoirs in naturally fractured basement. In these models a connected fracture network is assumed, but the details of the spatial relationships between fractures within a conceptually ellipsoidal stimulated zone arc ignored.

95lo4877 Coupled hydraulic, thermal and mechanlcal cot+ alderatlona for the almulatlon of hot dry rock reaervolra Kohl, T. et aL, Geothermics, Jun. 1995, 24, (3). 345-359. The cou led hydro-thcrmo-mechanical responses of a fractured media to forced B* md flow in a simple hot-dry-rock (HDR) system is invcsti atcd The geometry, a single fracture in a 2D matrix, was chosen in or I!c r to better understand the relevant processes for the long term bchaviour of HDR reservoir. Linear elastic effects of temperature and pore pressure

F rturbations on stress in the solid matrix are assumed as well as a non-

near joint closure law. Thermal transport by both conduction and advcc- tion is included in the fracture and the matrix. The results of these models highlight the importance of the coupled hydraulic thermal and mechanical processes on long term system bchaviour.

95104869 Modernlalng a apace and process heatlng Inatalla- tlon for an office and lnduatrial complex with the use of blo- mass In Moatolea, Spain Del Aguila, J. N. Ins& Tee. Con., Jan. 1995, (65). 15-23. (In Spanish) Discusses the modcmisation of the spa? and roccss heating plant for the administrative and manufacturin The buildings comprise 79,0

d of 28 lutchcn Lniturc enterprise in Spain. m . The existing heating system was

changed from steam with oil-fired boilers, to high-pressure hot water utilis- ing fuel oil and waste wood boilers with chippings availabc from the man- ufacturing process.

95lO4870 The performance of po tion coppice willow for energy pro r

clonal stands In short rota- uctlon

Dawson, W. M. et a& Biomass & Bioenergy, 1995,8, (I), l-5. The benefits of growing Salir spp ss a short rotation coppice in .alYclod (mixed) stands as compared to monoclonal stands are dcscri

95l0487l Proceedlnga of the 7th lnternatlonal EC Confar- enca Blomaaa for Energy and Industry Hall, D. 0. et aL, feds.), Ponte Press, distributed by James & James Publishers L& London, f80.00, $120.00, 1312 pp.

95lW072 Quantlflcatlon of polylaoprenea from some promla- Ing euphorba Ratti, N. et a& Bioresource Tech&, 1995,52, (3), 231-235. Quantitative and qualitative variations in hcxanc and acetone cxtractablcs from 10 cuphorbs were studied and compared with guayulc. There were significant differences in quality, as well as the quantity of oligomers in various cuphorbs. Hcxanc cxtractablcs were in relatively lower proportions than the acetone extractable&

95104873 Sap flow by the heat balance method ??ppllad to amall alu Sa//x tree8 In a abort-rotatlon forest Lindroth, A. et aL, Biomass & Bioenergy, 1995, 8. (1). 7-15. Tbc introduction of rapidly growink trees in so-called short-rotation for- cstry requires knowledge about their water use in order to select suitable land for plantations and to manage the stands in a proper way. In Sweden, different clones of Sali* arc usually used in short-rotation forestry today. The diameter of trees in such stands is much smaller cornoared with trees k traditional forestry. This required new methods to be developed in order to study water relations at the tree level. The aim of this study was to modify, apply and test the stem tissue heat balance method for long-term sap flow measurements on small size Salix trees.

95IO4878 ‘FRACTure’ - A ??lmulatlon coda for forced fluld flow and transport In fractured, poroua rock Kohl, T. and Hopkirk, R. J. Geothermics, Jun. 1995, 24, (3), 333-343. The 3D Finite Element Program FRACXurc was developed with the spc- cific sim of studying the coupling of interactive mechanisms in geoscience and in particular those relevant to the long term bchaviour of a hot

dXuz: reservoir. The flexible modular structure facilitates the addition of processes and elements to the existing library and the handling of linear and non-linear constitutivc laws and the calculation of their interactions. The hot dry rock applications involve essentially forced fluid flow of cool fluid injected into a hot fractured rock matrix. A study of the relevant processes required finite clement solutions for the hydraulic, thermal and elastic fields and especially their interactions. Attention is paid to modcl- ling the perturbations arising Tom poro-clastic and thermoclastic effects in the rock matrix and of a non-linear. stress dependent joint closure law.

QSlO4879 Geothermal energy Dickson, M. H. and Fanclli, M. (cc&.) UNESCO Energy Engineering Learnin tcr, PO f

Package, f19.95, John Wiley & Sons Ltd, Baffins Lane, Chiches- 9 IUD, UK Jun. 1995, 232 pp.

Geothermal energy, the exploitation of heat from the earth, has immense potential as a natural energy resource. Expertise in the utilisation and recovery of this highly cost-cffcctivc and non-waste-producing form of energy is growing rapidly. The contributing authors of this text each develop a specific area relating to the possible II= of geothermal energy and their effects on the community, taking into account the prevailing social and economic conditions.

95104880 Heat extractlon modalllng from forced fluld flow through almulatad fractured rock maaaea: Appllcatlon to tha Roaemanowea hot dry rock reaervolr Brucl, D. Georhermics. Jun. 1995, 24, (3). 361-374.

95/04874 Use of blologlcal ??olld fuel8 In ??ubatltuta heatlng plant at Luebbenau Baucr. F. et aL, Ber.-Dtsch. Wiss. Cu. Erdoel Erdgas Kohk, Tagung- sber, 1994.940.59-72. (In German) Discusses the fuel composition for the substitute hcatin plant at Leub- bcnau which is 50% wood. 3O% brown coal, and 20 4 plant biomass. Fluid&d bed firing installaiions were used; thi main com~ncnt was an atmospheric fluid&d bed boiler with flue gas recycle.

A series of modclling tools have been .developcd for fractured media, where the problem of connectivity is the major mechanism governing flow, and mass or heat transport. These arc Boolean models, where randomly distributed fractures arc generated in space. Flow and transport properties arc then distributed at a local scale for calculating global hydrauhc and dispersive bchaviour. Ensembles of rcalisations are generally generated. but arc difficult to condition on measurements. Based on the experimental results obtained at Fe-at depth ( c. 2.5km) at the Roscmanowca HDR site (Cornwall, UK), this approach LF shown to be appropriate for most of the available data. These data arc integrated in a single model and used to produce relevant estimates for the main hydraulic parameters.

Fuel and Energy Abstracta September 1995 347