ENCYCLOPAEDIAOF

HYDROCARBONS

ISTITUTO DELLA

ENCICLOPEDIA ITALIANAFONDATA DA GIOVANNI TRECCANI

©ALL RIGHTS RESERVED

Copyright byISTITUTO DELLA ENCICLOPEDIA ITALIANA

FONDATA DA GIOVANNI TRECCANI S.p.A.

2007

Printed in Italy

Photolith and printing byMARCHESI GRAFICHE EDITORIALI S.p.A.

Via Flaminia, 995/997 - 00189 Roma

CHAIRMANRoberto Poli

CHIEF EXECUTIVE OFFICERPaolo Scaroni

DIRECTORSAlberto Clô, Renzo Costi, Dario Fruscio, Marco Pinto, Marco Reboa,

Mario Resca, Pierluigi Scibetta

ISTITUTO DELLA ENCICLOPEDIA ITALIANA

PRESIDENTFrancesco Paolo Casavola

BOARD OF DIRECTORS

VICE PRESIDENTCesare Geronzi

Gian Mario Anselmi, Roberto Artoni, Pierluigi Ciocca, Marcello De Cecco, Giuseppede Vergottini, Giovanni Fiori, Ademaro Lanzara, Federico Pepe, Giovanni Puglisi,

Guido Rossi, Giuseppe Vacca

MANAGING DIRECTORFrancesco Tatò

SCIENTIFIC COUNCILCarlo Azeglio Ciampi, Francesco Cossiga, Oscar Luigi Scalfaro, Giovanni Conso,Rita Levi-Montalcini; Mario Agrimi, Adriano Alippi, Girolamo Arnaldi, BaccioBaccetti, Giuseppe Franco Bassani, Mario Beccari, Giuseppe Bedeschi, GiampioBracchi, Pietro Calissano, Luciano Canfora, Mario Caravale, Sergio Carrà, EnricoCastelnuovo, Francesco Clementi, Piero Coda, Benedetta Craveri, FrancescoD’Agostino, Giuseppe Dalla Torre, Nino Dazzi, Antonio Fazio, Domenico Fisichella,Giuseppe Galasso, Paolo Galluzzi, Emma Giammattei, Antonio Giuliano, GherardoGnoli, Augusto Graziani, Tullio Gregory, Maurizio Iaccarino, Carlo Jean,Fiorella Kostoris Padoa Schioppa, Luigi Labruna, Lucio Lanfranchi, Carlo MariaOssola, Giorgio Parisi, Sandro Petruccioli, Giovanni Pugliese Carratelli, GianTommaso Scarascia Mugnozza, Pietro Scoppola, Salvatore Settis, Francesco Sicilia,

Fulvio Tessitore, Edoardo Vesentini, Vera Zamagni, Ortensio Zecchino

BOARD OF AUDITORSGianfranco Graziadei, Chairman; Mario Perrone, Saverio Signori

Luciano Pagliaro, Delegate of the State Auditor’s Department

ENCYCLOPAEDIA OF HYDROCARBONS

PROJECT DIRECTORSMario Beccari, Ugo Romano

SCIENTIFIC CO-ORDINATING COMMITTEEPier Federico Barnaba, Piero Bernardini, Giovanni Brighenti, Sergio Carrà, Alberto Clô,

Carlo Giavarini, Renzo Mazzei, Ferruccio Trifirò

EDITORIAL DEPARTMENT

Chief Editor: Carlo Amadei

Technical-Scientific Area. Supervisors: Fabio Sebastiani; Maria Teresa Amoroso. Chemistry: AndreaCiccioli, Alessandro Di Menno Di Bucchianico, Antonio Di Meo - Physics: Maria GraziaIanniello - Engineering: Lucilla Monteleone, Roberto Steindler - Biological, Geological andNatural Sciences: Francesca Beolchini, Simona Martullo, Francesca Ricci, Paola Vinesi

Legal, Economics and Historical-Geographical Area. Supervisors: Giandomenico Patrizi; Pino Bongiorno.Law: Fabio Di Fonzo, Fabiana Di Porto, Bianca Maria Raganelli - Economics: Chiara d’Auria,Giuseppe Smargiassi - Geography: Arianna Ballabene - History: Silvia Dionisi

Italian language edition. Supervisor: Enrico Piccioni. Cristiana Baldazzi, Ilenia Romana Cassetta,Fabio Catino, Claudio Censori, Marina Chiarioni, Katia Furìa, Patrizia Greganti, TomásKubícek (illustrations), Michela Mastroddi, Enza Milanesi, Stefano Petrocchi, Tiziana Provvidera,Laura Volpe

English language edition. Co-ordination: Cosima Campagnolo. Donald Blair Bartlett, Janice Calf,Anne Colbeck, Johanna Erhardt, Helenka Dodge Kinnan, Patrick O’Keeffe, Mary AnneTafuri. Consultant: Peter Joseph Glendening.Translators: Andrea Baldi, Fabrizio Balsamo, Richard Bates, Massimo Benedetti, AnthonyMartin Cafazzo, Fabio Catino, Paolo Del Giudice, Paul Michael Garwood, Peter JosephGlendening, H.J. Michael Harris, Erika Louisa Milburn, Gian Mario Moggio, Stefano Salpietro,Maria Serena Scariolo, Ruth Patricia Williams

Secretaries: Pasqualina Leone, Tiziana Pieretti

ART DEPARTMENT

Art Director: Gerardo Casale

Graphics: Giuseppe De GregoriIllustration sourcing: Daniele Piselli; Claudio Cigognetti; Anna Maria Ciai, Bernardo Ruzicka,Angelo ZanniDrawings: Marina Paradisi; Giuseppina Elia, Marco Evangelista, Massimo Montelli, Anna Olivieri,Paola Salvatori (cartography)Graphics and layout: Giuseppe De Gregori (control)Quality control: Anna Rita De NardisSecretaries: Aurora Corvesi, Carla Proietti Checchi

LIBRARY

Gabriella Miggiano; Elsa Adducci, Marina Battaglini, Massimo Menna, Giuliana ScudderSecretary: Gabriella Michetti

PUBLISHING DEPARTMENT

Publishing administration: Luisa Fusé; Cecilia Rucci, Mirella AielloPlanning: Luisa Cinquina; Alessia Pagnano, Tiziana PicconiQuality control: Rosalba Lanza; Simonetta PaoluzziIndustrial production: Maria Devrushian; Loreta LucchettiSecretary: Eliana Naddeo

PUBLISHING DIRECTORMassimo Bray

volume iii

NEW DEVELOPMENTS:ENERGY, TRANSPORT,

SUSTAINABILITY

SCIENTIFIC CO-ORDINATIONUgo Romano

ENCYCLOPAEDIA OF HYDROCARBONS

XV

INDEX OF VOLUME III

NEW DEVELOPMENTS:ENERGY, TRANSPORT,

SUSTAINABILITY

1 – FROM PRIMARY SOURCES TO THE MARKET

Dante Casati, Raffaella Turatto1.1 – EVOLVING TECHNOLOGIES AND POSSIBLE SCENARIOS 3

1.1.1 – Scenarios and strategic decisions 31.1.2 – Scenarios and reference markets 31.1.3 – Factors for change and technological innovation 41.1.4 – The macroeconomic scenario 51.1.5 – Energy scenario 51.1.6 – Technological scenario 61.1.7 – The development scenario for the issue of ‘environment and sustainability’ 15

2 – HYDROCARBONS FROM NON-CONVENTIONAL AND ALTERNATIVEFOSSIL RESOURCES

Maurice B. Dusseault2.1 – OIL FROM NON-CONVENTIONAL SOURCES 21

2.1.1 – Non-conventional fossil fuels 212.1.2 – Pressure-driven viscous oil technologies 252.1.3 – Gravity drainage technologies 322.1.4 – In situ combustion option 392.1.5 – Technology mixing and sequencing 412.1.6 – Reservoir screening criteria 442.1.7 – Oil shales and mineable oil sands 452.1.8 – Upgrading and transportation 482.1.9 – Environmental impact 50

2.1.10 – Predictions 52

Charles M. Boyer, Joseph H. Frantz, Creties D. Jenkins2.2 – NON-CONVENTIONAL GAS 57

2.2.1 – Introduction 572.2.2 – Reservoir fundamentals 60

2.2.3 – Drilling, completion, and production 722.2.4 – Resources and reserves 742.2.5 – Technology and future trends 752.2.6 – Project summaries and comparisons of applied technologies 772.2.7 – International potential for coalbed methane and shale gas 792.2.8 – Conclusions 80

Gian Paolo Borghi2.3 – GAS HYDRATES 85

2.3.1 – Introduction 852.3.2 – The structure of hydrates 852.3.3 – Hydrates as a problem in the oil industry 912.3.4 – Hydrates as a future energy resource 982.3.5 – Research and development activities in the gas hydrates sector 107

Alberto Delbianco2.4 – HYDROCARBONS FROM THE DIRECT LIQUEFACTION OF SOLID FUELS 113

2.4.1 – Introduction 1132.4.2 – Liquefaction technology 1202.4.3 – New-generation processes 1262.4.4 – Properties of coal liquids 1282.4.5 – Further developments of the technology 1292.4.6 – Integration with hydrogen production technologies 1332.4.7 – Process economics and development potential of the technology 134

Alberto Delbianco, Romolo Montanari2.5 – EMERGING TECHNOLOGIES FOR THE CONVERSION OF RESIDUES 137

2.5.1 – Introduction 1372.5.2 – Properties and chemical characteristics of non-conventional oils 1392.5.3 – Chemistry of the conversion and upgrading processes 1432.5.4 – Carbon rejection technologies 1472.5.5 – Hydrogen addition technologies: hydrocracking 1512.5.6 – Technologies for the exploitation of oil shale 1562.5.7 – Main development projects 158

Giuseppe Bellussi, Roberto Zennaro2.6 – HYDROCARBONS FROM NATURAL GAS 161

2.6.1 – Introduction 1612.6.2 – Gas to Liquids process by means of the Fischer-Tropsch reaction 1632.6.3 – Products 179

3 – NEW UPSTREAM TECHNOLOGIES

Ali Daneshy3.1 – UPSTREAM TECHNOLOGIES. NOVEL WELL AND PRODUCTION ARCHITECTURE 185

3.1.1 – Introduction 1853.1.2 – Horizontal drilling 1863.1.3 – Multilateral wells 190

XVI

3.1.4 – Downhole flow regulators 196

3.1.5 – Novel well architectures 198

3.1.6 – Flow optimization 205

3.2 – ENHANCED OIL RECOVERY 209

Emilio Causin

3.2.1 – Processes 209

Steven L. Bryant

3.2.2 – Recovery factor optimization 214

Thomas Lockhart, Francesco Crescenzi

3.3 – SOUR OIL AND GAS MANAGEMENT 237

3.3.1 – Introduction 237

3.3.2 – Origin of H2S in oil and gas accumulations 238

3.3.3 – H2S removal in small volume plants 241

3.3.4 – High volume sour gas treatment processes 243

3.3.5 – Sour gas re-injection 256

3.3.6 – Sulphur storage and disposal 260

3.3.7 – The sulphur market and new uses 264

Francesca de Ferra

3.4 – BIOTECHNOLOGIES APPLIED TO OIL AND GAS EXPLORATION, PRODUCTION

AND CONVERSION 271

3.4.1 – Microbiology associated with hydrocarbons 271

3.4.2 – Reactions 274

3.4.3 – Applications 281

3.4.4 – Biological activation of methane 292

4 – ENERGY CARRIERS

Mario Marchionna

4.1 – FROM SOURCES TO MARKET: ENERGY CARRIERS 301

4.1.1 – Introduction 301

4.1.2 – Life cycle of the energy carrier 301

4.1.3 – Conventional energy carriers 304

4.1.4 – Innovative energy carriers 308

4.1.5 – Conclusions 315

Marco Nicola Carcassi

4.2 – THE HYDROGEN ECONOMY 319

4.2.1 – Introduction 319

4.2.2 – Characteristics of hydrogen 321

4.2.3 – Production, transportation and storage of hydrogen 323

4.2.4 – Advantages and disadvantages of hydrogen as an energy vector 325

4.2.5 – Research and development programmes 329

4.2.6 – Conclusions 333

XVII

John R. Benemann, Paola Pedroni4.3 – BIOLOGICAL PRODUCTION OF H2: MECHANISMS AND PROCESSES 337

4.3.1 – Introduction 3374.3.2 – Biological catalysts for H2 production 3394.3.3 – Bioreactors for H2 production 3414.3.4 – Photobiological H2 production processes 3444.3.5 – Dark fermentations 3504.3.6 – Biohydrogen applications and potential 355

Ernesto Scafè4.4 – TRANSPORT AND STORAGE OF HYDROGEN 361

4.4.1 – Introduction 3614.4.2 – Traditional transport and storage 3614.4.3 – Innovative transport and storage 364

5 – POWER GENERATION FROM FOSSIL RESOURCES

Ennio Macchi, Giovanni Lozza, Stefano Consonni5.1 – LARGE-SCALE ELECTRICAL GENERATION SYSTEMS 377

5.1.1 – Introduction 3775.1.2 – Steam electric power stations 3845.1.3 – Gas turbines 3975.1.4 – Combined cycles 4045.1.5 – Gasification and combined cycles (IGCC) 413

Ennio Macchi, Giovanni Lozza5.2 – INDUSTRIAL COGENERATION 421

5.2.1 – Introduction 4215.2.2 – Plants with external combustion prime movers 4255.2.3 – Plants with internal combustion prime movers 428

Ennio Macchi, Stefano Campanari5.3 – DISTRIBUTED GENERATION 435

5.3.1 – Introduction 4355.3.2 – Microgeneration technologies 4385.3.3 – Trigeneration 457

Ivano Miracca, Mario Molinari5.4 – POWER GENERATION WITH CARBON DIOXIDE SEGREGATION 461

5.4.1 – Introduction 4615.4.2 – Technological development 4665.4.3 – Future prospects 472

Francesco Pittalis, Vincenzo Antonucci5.5 – FUEL CELLS FOR STATIONARY GENERATION 475

5.5.1 – Historical outlines 4755.5.2 – Introduction 477

XVIII

5.5.3 – Fuels 4825.5.4 – Low temperature fuel cells 4855.5.5 – Medium and high temperature fuel cells 491

Maurizio Cumo5.6 – ADVANCED NUCLEAR SYSTEMS 499

5.6.1 – Introduction 4995.6.2 – The six fourth-generation nuclear systems 5015.6.3 – High-temperature reactors 5055.6.4 – Reduction in the radiotoxicity of waste 5085.6.5 – The III+ generation reactors 510

Giovanni Battista Zorzoli5.7 – TRANSMISSION, DISTRIBUTION AND STORAGE OF ELECTRIC ENERGY 515

5.7.1 – Introduction 5155.7.2 – Storage of electric energy 5155.7.3 – The first steps 5175.7.4 – Types of transmission networks and connected problems 5185.7.5 – The North American network 5205.7.6 – The European networks 5225.7.7 – Problems posed by deregulation 5245.7.8 – Examination of a typical case of blackout 5255.7.9 – Distribution networks 527

6 – POWER GENERATION FROM RENEWABLE RESOURCES

6.1 – SOLAR ENERGY CONVERSION 531Mauro Vignolini

6.1.1 – Concentration systems 531Francesca Ferrazza

6.1.2 – Photovoltaic technology 547

Jacques Ruer6.2 – WIND POWER GENERATION 561

6.2.1 – The wind resource 5616.2.2 – Theory of wind turbines 5636.2.3 – Wind turbine regulation systems 5646.2.4 – Turbine equipment 5666.2.5 – Typical characteristics of modern large turbines 5706.2.6 – Other types of wind turbines 5706.2.7 – Development of onshore wind energy 5716.2.8 – Development of offshore wind energy 571

Wavegen6.3 – WAVE AND TIDAL POWER GENERATION 575

6.3.1 – Introduction 5756.3.2 – Historical perspective 579

XIX

6.3.3 – Current status 582

6.3.4 – Estimation of wave energy resource and device performance 586

6.3.5 – Environmental impact of wave and tidal devices 590

6.3.6 – Global prospects for the energy industry 591

Mario Fanelli, Piero Manetti, Mary Hana Dickson, Leonardo Zan

6.4 – GEOTHERMAL ENERGY 595

6.4.1 – Introduction 595

6.4.2 – Nature of geothermal resources 597

6.4.3 – Geothermal exploration 603

6.4.4 – Utilization of geothermal resources 604

6.4.5 – Environmental impact 609

Vito Pignatelli, Andrea Robertiello

6.5 – BIOMASS FOR RENEWABLE ENERGY 611

6.5.1 – Introduction 611

6.5.2 – The role of biomass in the energy spectrum 613

6.5.3 – Fuels from biomass 615

6.5.4 – Technologies for the use of biomass energy 621

6.5.5 – Conclusions 628

7 – ENERGY SYSTEMS ANALYSIS

Alberto Tintinelli

7.1 – LIFE CYCLE ASSESSMENT AND ENERGY SYSTEMS 633

7.1.1 – Introduction 633

7.1.2 – Life cycle assessment method 634

7.1.3 – Applications of life cycle assessment in the field of energy systems 641

Teresa L. Hill, David H. Marks, Jefferson W. Tester

7.2 – PATHWAYS TO A SUSTAINABLE ENERGY FUTURE 651

7.2.1 – Introduction 651

7.2.2 – The future of fossil energy 652

7.2.3 – Alternatives to fossil 655

7.2.4 – Energy systems 664

7.2.5 – Choosing options for a sustainable energy future 666

7.2.6 – Conclusions 668

8 – TRANSPORT

Alessandro Piccone, Giorgio Cornetti

8.1 – RECIPROCATING INTERNAL COMBUSTION ENGINES 673

8.1.1 – Introduction 673

8.1.2 – Architecture 677

8.1.3 – Combustion, emissions and control system 684

8.1.4 – Evolution 695

XX

Jacopo D’Andria8.2 – HYBRID DRIVE SYSTEMS 699

8.2.1 – Introduction 6998.2.2 – Current environmental problems and potential solutions 7008.2.3 – Hybrid-electric vehicles: historical outline and current situation 7038.2.4 – Features of the hybrid systems in use 7048.2.5 – Strengths and weaknesses of hybrid-electric vehicles8.2.6 – Possible developments in components for hybrid-electric vehicles8.2.7 – The future of the market for hybrid-electric vehicles

Fulvio Giavazzi, Patrizia Buttini, Carlo Perego8.3 – POLLUTING EMISSIONS CAUSED BY TRANSPORT 717

8.3.1 – Pollutants emitted by motor vehicles 7178.3.2 – Low-emission fuels 729

Riccardo Maione, Luigi D’Elia8.4 – LUBRICATION AND LUBRICANTS 751

8.4.1 – Introduction 7518.4.2 – Functions and performance of lubricants for heavy-duty vehicles 7578.4.3 – Main components of lubricants for heavy-duty vehicles 7648.4.4 – Lubricants for industry 768

9 – SUSTAINABILITY

Andrea Robertiello, Alberto Tintinelli9.1 – THE OIL INDUSTRY TOWARDS ZERO IMPACT 775

9.1.1 – Introduction 7759.1.2 – Oil cycle: upstream 7769.1.3 – Oil cycle: downstream 7879.1.4 – Natural gas cycle 7939.1.5 – Operating instruments available for eliminating environmental impact 795

George J. Stosur9.2 – SUSTAINABLE DEVELOPMENT IN THE OIL AND GAS INDUSTRY 801

9.2.1 – Defining sustainable development 8019.2.2 – The need for sustainable development 8029.2.3 – The precautionary principle 8039.2.4 – Industrial activities related to sustainable development 8039.2.5 – Greenhouse gases and global warming 8079.2.6 – Biodiversity and loss of habitat 8089.2.7 – The role of technology and research and development 8089.2.8 – Regulatory processes at corporate, country and global level 809

Paul Freund9.3 – CO2 CAPTURE AND STORAGE FROM FOSSIL FUELS 811

9.3.1 – Introduction 8119.3.2 – Sources of CO2 812

XXI

9.3.3 – Methods of capturing CO2 8149.3.4 – Transportation of CO2 8189.3.5 – Storage of CO2 8199.3.6 – Costs and benefits 8249.3.7 – Environmental impact, risks, legal aspects and public acceptance 8299.3.8 – Monitoring, verification and commercial/regulatory requirements 8329.3.9 – Conclusions 834

John R. Benemann, Paola Pedroni9.4 – BIOFIXATION OF FOSSIL CO2 BY MICROALGAE FOR GREENHOUSE GAS ABATEMENT 837

9.4.1 – Introduction 8379.4.2 – Photosynthesis, microalgae productivity and GHG abatement 8399.4.3 – Microalgae cultivation systems and CO2 capture 8439.4.4 – Microalgae harvesting and conversion to fuels 8479.4.5 – Microalgae multipurpose processes for GHG abatement 8519.4.6 – Economics and R&D issues 8559.4.7 – GHG abatement potential with microalgae processes 857

Abigail Entwistle, Timothy Reed, Paola Pedroni9.5 – BIODIVERSITY AND THE OIL AND GAS SECTOR 863

9.5.1 – Introduction 8639.5.2 – Biodiversity and the oil and gas sector 8669.5.3 – Operationalizing biodiversity awareness in the oil and gas sector 870

Ugo Romano, Franco Rivetti9.6 – CHEMICAL INDUSTRY AND SUSTAINABLE DEVELOPMENT 879

9.6.1 – Sustainability 8799.6.2 – Sustainability in the chemical industry 8819.6.3 – Innovation areas for sustainable chemistry 8879.6.4 – Looking ahead 907

10 – ENVIRONMENTAL TECHNOLOGIES

Ivo Allegrini10.1 – ATMOSPHERIC CHEMISTRY 915

10.1.1 – Introduction 91510.1.2 – Atmospheric chemistry in the gas phase 91610.1.3 – Atmospheric chemistry in the aqueous phase 92510.1.4 – Depletion of stratospheric ozone 931

Ivo Allegrini, Patrizia Buttini10.2 – EMISSION AND CONTROL OF GREENHOUSE GASES 937

10.2.1 – Introduction 93710.2.2 – Sources of greenhouse gas emissions 94510.2.3 – Techniques for measuring greenhouse gases in ambient air 94810.2.4 – Techniques for measuring greenhouse gases in emissions 94910.2.5 – Strategies to control greenhouse gases 950

XXII

Giovanni Grillo, Paola Pedroni10.3 – POLLUTION PROCESSES IN SOIL AND WATER, MONITORING AND RISK ANALYSIS 955

10.3.1 – Introduction 95510.3.2 – Migration and transformation of hydrocarbons in the environment 95510.3.3 – Environmental characteristics of the principal groups of pollutants 95910.3.4 – Characterization and monitoring of pollution at a site 96010.3.5 – Modelling the movement of pollutants 96410.3.6 – Evaluation of the pollution at a site: risk assessment 966

XXIII

XXV

NOTES

UNITS OF MEASUREMENT

The units of measurement generally adopted are those of the Système International (SI), with corresponding mul-tiples and submultiples. Only in particular contexts, typically connected with the petroleum industry, certain non-SI units of current use have been maintained.

Main units of measurement adopted

TERMINOLOGY AND SPELLING

In the sectors of petroleum engineering and chemistry, of the petrochemical industry and of the earth sciences,specific terms, acronyms and expressions are frequently used. The criterion adopted in this work is based on theirfrequency of use, i.e. given two possible terms, the more common one has been used. British spelling, according to the most authoritative reference works, has been adopted.

ampere Aangstrom Åatomic mass unit ubar barbarrel bblbecquerel BqBritish thermal unit Btucalorie calcandela cdcoulomb Cdarcy Dday ddecibel dBdegree Celsius °Cdegree Fahrenheit °Fdegree (sexagesimal) °electron volt eVfarad Ffoot ' (ft)gram ggray Gyhectare ha

henry Hhertz Hzhorse-power hphour hinch '' (in)joule Jkelvin Kkilogram kgkilowatt-hour kWh litre llumen lmlux lxmetre msquare metre m2

cubic metre m3

minute (angle) minute (time) minmole molnewton Nnit ntohm Ωparts per million ppm

pascal Papoise Ppound lbpounds per square inch psiradian radsecond (angle)

second (time) ssiemens Ssievert Svstandard cubic foot scf or SCF or sft3

steradian srstock tank barrel stb stokes Sttesla Ttonne ttonnes of oil equivalent toevolt Vwatt Wweber Wbyard ydyear yr

XXVI

CHEMICAL NOMENCLATURE

In the nomenclature of simple compounds, the rules of IUPAC (International Union of Pure and Applied Chemistry)have been adopted as far as possible, traditional names being limited to the cases admitted by IUPAC. When thereare two or more names admitted, the commonest one is adopted.Two principal exceptions to the above rule have been applied in this work:• For organic compounds used in the petrochemical industry, the name adopted is that listed in: Wells G.M.

(1999) Handbook of petrochemicals and processes, Aldershot, Ashgate; Brookfield (VT), Gower.• The British English spelling of sulphur and sulphur containing compounds is adopted.

TRANSLITERATIONS

In writing names belonging to other languages with an alphabet other than the Latin alphabet, the RomanizationTables compiled by the Library of Congress of Washington have been applied, introducing however certain modificationsintended to reduce to a minimum the number of diacritical marks, and – in particular in the case of Arabic and Persian– adopting a number of transliterations by now accepted in local and international usage.

Opposite page:The Val d’Agri deposits, along with those in the Sauro Valley, make up the largest energy resource ever discovered in Italy.In the picture a drill in the drilling stage. In the subsequent production stage the drill is no longer in sight: the wellhead islodged in an underground space, substantially reducing its visual effect while guaranteeing utmost safety. Technological advances in the energy industry allow the possibility to minimize the environmental impact and respectbiodiversity.