UNIVERSIDAD DE JAÉN ESCUELA POLITÉCNICA SUPERIOR DEPARTAMENTO DE INGENIERÍA ELÉCTRICA TESIS DOCTORAL GASIFICATION APPLIED TO THE VALORIZATION OF OLIVE GROVE AND OLIVE MILL RESIDUES PRESENTADA POR: BÁRBARA DE MENA PARDO DIRIGIDA POR: DR. D. DAVID VERA CANDEAS DR. D. FRANCISCO JURADO MELGUIZO JAÉN, 7 DE ABRIL DE 2017 ISBN 978-84-9159-076-7 Gasification applied to the valorization of olive grove and olive mill residues 2 Gasification applied to the valorization of olive grove and olive mill residues Chapter 1. Introduction. Objectives and structure of the thesis ................................................. 9 Chapter 1. Introduction. Objectives and structure of the thesis .................................................... 10 1.1. Introduction: Why valorise the residues of the olive sector? ........................................... 10 1.2. Objectives of this thesis ...................................................................................................... 12 1.3. Thesis structure ..................................................................................................................... 13 Chapter 2. The olive oil sector in Europe and in Spain................................................................ 15 2.1. The olive oil sector in Europe and in Spain ..................................................................... 16 2.2. Olive oil production methods ............................................................................................ 19 2.2.1. Olive presses ....................................................................................................................... 19 2.2.2. Decanter centrifugation: three phases and two phases ...................................... 20 2.3. Definition and characterization of the olive and olive oil industry residues and by- products ............................................................................................................................................... 21 2.3.1. Pomace ................................................................................................................................ 22 2.3.2. Orujillo (exhausted pomace) ...................................................................................... 23 2.3.3. Olive stones ................................................................................................................... 23 2.3.4. Leaves and twigs .......................................................................................................... 24 2.3.5. Prunings .......................................................................................................................... 25 2.4. Physico-chemical characteristics of biomass ................................................................. 26 2.4.1. Bulk density ........................................................................................................................ 26 2.4.2. Moisture content .......................................................................................................... 27 2.4.3. Ignition temperature .................................................................................................... 27 2.4.4. Heating value................................................................................................................. 27 2.4.5. Elemental analysis (ultimate analysis) .................................................................... 29 2.4.6. Proximate analysis ....................................................................................................... 30 2.4.7. Ash content .................................................................................................................... 32 2.5. Physico-chemical characteristics of the olive and olive oil industry residues and by- products ....................................................................................................................................... 32 2.5.1. Orujo, olive pomace ......................................................................................................... 32 2.5.2. Orujillo, exhausted olive oil pomace ........................................................................ 33 2.5.3. Olive stones ................................................................................................................... 34 3 Gasification applied to the valorization of olive grove and olive mill residues 2.5.4. Leaves and twigs .......................................................................................................... 35 2.5.1. Prunings ............................................................................................................................... 36 2.6. Availability of the residues in Andalucía (Spain) and their valorization potential .. 36 2.6.1. Orujo, olive pomace ......................................................................................................... 36 2.6.2. Orujillo, exhausted olive oil pomace ........................................................................ 38 2.6.3. Olive stones ................................................................................................................... 39 2.6.4. Leaves and twigs .......................................................................................................... 40 2.6.5. Prunings ........................................................................................................................... 41 Chapter 3. Biomass valorization technologies............................................................................. 44 3.1. Direct combustion ............................................................................................................... 46 3.2. Pyrolysis ................................................................................................................................ 47 3.3. Gasification ........................................................................................................................... 48 3.3.1. Gasifier types ..................................................................................................................... 49 3.4. Anaerobic digestion ............................................................................................................. 61 3.5. Alcoholic fermentation ....................................................................................................... 62 Chapter 4. Technologies applicable to the use of biomass ....................................................... 63 4.1. Internal combustion machines ......................................................................................... 64 4.1.1. Steam turbines ................................................................................................................... 64 4.1.2. Organic Rankine cycle (ORC) ......................................................................................... 67 4.1.3. Internal Combustion Engines ......................................................................................... 70 4.1.4. Gas turbines ....................................................................................................................... 73 4.1.5. Microturbines ..................................................................................................................... 74 4.2. External combustion machines ........................................................................................ 75 4.2.1. Externally-fired gas turbines .......................................................................................... 76 4.2.2. Stirling engines ............................................................................................................. 78 4.3. Fuel cells ................................................................................................................................ 79 Chapter 5. Comparison between externally fired gas turbine and gasifier-gas turbine system for the olive oil industry ......................................................................................................... 82 5.1. Gasifier and conventional gas turbine ............................................................................ 83 5.1.1. Gasifier subsystem (blocks: 2, 3, 10 and 18) ................................................................. 85 5.1.2. Gas cleaning and cooling ................................................................................................ 86 4 Gasification applied to the valorization of olive grove and olive mill residues 5.1.3. CHP subsystem: microturbine ........................................................................................ 86 5.2. Gasifier and externally fired gas turbine (EFGT) power plant .................................... 87 5.2.1. Plant description ............................................................................................................... 89 5.3. Results obtained ................................................................................................................... 91 5.3.1. Gasification system (FBG-GT) ......................................................................................... 92 5.3.2. EFGT plant ...................................................................................................................... 97 5.4. Comparison between conventional GT and EFGT. Conclusion ................................ 100 Chapter 6. Study of a downdraft gasifier and gas engine fueled with olive oil industry wastes 102