Biomass thermochemical conversion in small scale facilities

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Universidade de Aveiro 2020

Departamento de Economia, Gestão,

Engenharia Industrial e Turismo

MARIO ALEJANDRO

HEREDIA SALGADO

CONVERSÃO TERMOQUÍMICA DA BIOMASSA EM

INSTALAÇÕES DE PEQUENA ESCALA

BIOMASS THERMOCHEMICAL CONVERSION IN

SMALL SCALE FACILITIES

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Universidade de Aveiro 2020

Departamento de Economia, Gestão, Engenharia Industrial e Turismo

MARIO ALEJANDRO

HEREDIA SALGADO

CONVERSÃO TERMOQUÍMICA DA BIOMASSA EM

INSTALAÇÕES DE PEQUENA ESCALA

BIOMASS THERMOCHEMICAL CONVERSION IN

SMALL SCALE FACILITIES

Tese apresentada à Universidade de Aveiro para cumprimento dos requisitos necessários à obtenção do grau de Doutor em Sistemas Energéticos e Alterações Climáticas, realizada sob a orientação científica do Doutor Luís António da Cruz Tarelho, Professor Associado do Departamento de Ambiente e Ordenamento da Universidade de Aveiro e co-orientação do Doutor Manuel Arlindo Amador de Matos, Professor Auxiliar do Departamento de Ambiente e Ordenamento da Universidade de Aveiro

This work was supported by the Instituto de Fomento al Talento Humano-IFTH and the Republic of Ecuador through the scholarship AR2Q-8496. It is

acknowledged the support to CESAM - Centre for Environmental and Marine Studies, POCI-01-0145-FEDER-007638 (FCT Ref. UID/AMB/50017/2013), financed by national funds through the FCT/MEC and co-financed by FEDER under the PT2020 Partnership Agreement

Este trabalho teve apoio do Instituto de Fomento al Talento Humano –IFTH e a República do Ecuador através da bolsa ARQ-8496. Reconhece-se o apoio ao CESAM – Centro de Estudos Ambientais e Marinhos, POCI-01-0145-FEDER-007638 (FCT Ref. UID/AMB/50017/2013), financiado por fundos nacionais através da FCT/MEC e

co-financiado pela FEDER no âmbito do Acordo de Parceria PT2020

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Dedicated especially to my parents Mario and Paty, to my brothers Adrian and Estefania, and my wife María José.

-No esperaba yo menos de la gran magnificencia vuestra, señor mío – respondió don Quijote-, y así os digo que el don que os he pedido y de vuestra liberalidad me ha sido otorgado es que mañana en aquel día me habéis de armar caballero, y esta noche en la capilla deste vuestro castillo velaré las armas, y mañana como tengo dicho, se cumplirá lo que tanto deseo, para poder como se debe ir por todas las cuatro partes del mundo buscando las aventuras, en pro de los menesterosos, como está a cargo de la caballería y de los caballeros andantes, como yo soy, cuyo deseo a semejantes fazañas es inclinado.

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The jury/ O júri

President / presidente Prof. Doutor Vasile Staicu

Professor Catedrático, Universidade de Aveiro

Members / vogais Prof. Doutor Mário Manuel Gonçalves da Costa

Professor catedrático do do Instituto Superior Técnico, Universidade de Lisboa

Prof. Doutor Nuno Carlos Lapa dos Santos Nunes

Professor auxiliar da Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa

Prof. Doutora Marta Alexandra da Costa Ferreira Dias

Professor auxiliar do Departamento de Economia, Gestão, Engenharia Industrial e Turismo, Universidade de Aveiro

Prof. Doutor Valter Bruno Reis e Silva

Investigador Auxiliar, Instituto Politécnico de Portalegre

Supervisor / orientador Prof. Doutor Luís António da Cruz Tarelho

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acknowledgments I want to thank the citizens of Ecuador that through their taxes contributed to the scholarship that made this study possible together with those that had the will of using these resources to promote knowledge production and scientific progress. Rest assured that I have done my best in this research to honor your efforts and sacrifices, putting myself at the service of those which labor our fields day after day and foremost, to the service of the children’s now that, when adults, can make use of this information to continue taking care of this land. I deeply thank my supervisor, Professor Luís Tarelho, for trusting my decisions during the dark moments and for representing the ideal of work, creativity, engineering, and science every day. I also thank my co-supervisor Professor Arlindo Matos and to the Aveiro University that is the place where I found a vocation and where I always may back. Finally, I would like to thank all those people that have trusted my ideas, and foremost, that had supported me to build and mature them. As this space is limited in size I am forced to keep all of them anonymous. Nonetheless, hope I had made sure in these five years of making them feel my gratitude and respect.

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palavras-chave Agroindústria; Agroresíduos; Combustão; Pirólise; Reactor de parafuso, Biochar; Pesquisa ação participativa.

resumo A conversão energética da biomassa residual gerada no setor agroindustrial do

Equador é uma alternativa para reduzir o consumo de combustíveis fósseis, mitigar os impactos ambientais associados à disposição inadequada de resíduos e reduzir a dependência da agroindústria aos subsídios dos combustíveis fósseis. O sector agroindustrial dá origem a grandes quantidades de biomassa residual que se caracteriza por apresentar alto teor de cinzas e baixa densidade aparente, e cujo aproveitamento energético tem sido desprezado por razões relacionadas com as tecnologias disponíveis. A combustão deste tipo de biomassa no protótipo de queimador horizontal (HBP) desenvolvido neste estudo mostrou-se problemática. Problemas de transporte (estagnação e formação de abóbada) e arrastamento do combustível pela corrente de ar de combustão produziram instabilidades na frente da chama e impediram um processo de combustão estável. Dos agro-resíduos estudados, apenas a casca do fruto da palmeira de óleo de palma (KS) pode ser queimada obedecendo aos padrões Europeus de eco-design, nomeadamente, a concentração de CO no efluente foi inferior a 250 mg/Nm3_{(corrigido a 11% vol.} O2, gás seco). No entanto, a gestão das cinzas do processo de combustão ainda precisa ser melhorada.

Em alternativa observou-se que um reator de pirólise modular de parafuso seguido de um queimador dos gases de pirólise, ambos desenvolvidos no âmbito deste trabalho, é capaz de processar a maioria dos agro-resíduos de baixa densidade e alto teor de cinzas considerados neste estudo. Foram observadas condições operacionais auto-térmicas quando a matéria-prima do processo de pirólise foi KS. Nessas condições, a concentração de CO no gás de combustão (197 mg/Nm3_{a 11% vol. O}

2, gás seco) foi inferior ao limite estabelecido pelas normas Europeias de eco-design. Para o restante dos resíduos agrícolas considerados neste estudo (cascas de café, talos de quinoa e cascas de quinoa), a combustão do gas de pirólise ocorreu em condições de co-combustão, ou seja, é necessária uma entrada adicional de energia térmica para manter a temperatura constante nos processos de combustão e pirólise. As propriedades físico-químicas do biochar produzido dependem da matéria prima e das condições de operação do reator, tendo sido observado que, em todos os casos, as razões molares H/Corg e O/Corg estão de acordo com as diretrizes para a produção sustentável de biochar. Observa-se ainda que a eficiência exergética na produção de biochar gira em torno de 65,5%. Essa estimativa considera um sistema totalmente integrado onde o excesso de energia térmica gerada durante a carbonização é usado para produzir trabalho (por exemplo, secagem).O período de retorno de referência associado a uma instalação de pirólise no Equador, assumindo um preço de biochar entre 3,5 e 5,3 USD / t, varia entre 3 e 5 anos. No entanto, é reconhecida uma alta incerteza quanto ao preço do mercado de biochar. Em geral, os subsídios aos combustíveis fósseis impedem a transição para o uso de biomassa residual como fonte de energia. Independentemente das mudanças na política de subsídios, o aumento da eficiência exergetica e a otimização dos custos de capital e operação associados às infraestruturas de valorização da biomassa são alternativas para promover a utilização sustentável da biomassa residual gerada nos setores agroindustriais estudados.

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keywords Agro-industry; Agro-residues; Combustion, Pyrolysis; Auger reactor; Biochar; Participative Action Research.

abstract The energetic conversion of the residual biomass generated in the Ecuadorian

agro-industrial sector is an alternative to reduce the consumption of fossil fuels in thermal appliances, mitigate the environmental impacts associated with improper residues disposition and to reduce the agroindustry dependency on subsidies to fossil fuels. In general, most of the residual biomass generated in the agro-industrial sector would have at least one of these characteristics: high ash content and low bulk density. Combustion of low bulk density biomass in the horizontal burner prototype (HBP) developed in this study show to be problematic. Conveying issues (e.g. stagnation and dome formation) and fuel dragging by the combustion air stream produced instabilities in the flame front and prevented a steady combustion process. From the agro-residues analyzed in this study, only palm oil kernel shells (KS) can be converted into thermal energy observing the European eco-design standards, that is, the CO concentration in the flue gas was below 250 mg/Nm3_{(values corrected to 11%} vol. O2, dry gas). Nonetheless, the ash management within the combustion process must be improved. It was observed that a pyrolysis process, that is, the pyrolysis small and modular auger reactor developed in this thesis can make effective use of most of the low density and high ash content agro-residues considered in this study. Auto-thermal operating conditions were observed when the feedstock of the pyrolysis process was KS. In these conditions, the CO concentration in the flue gas (197 mg/Nm3_{at 11% vol. O}₂_{, dry gas) was lower} than the limit established by the European eco-design standards. For the rest of the agro-residues considered in this study (coffee husks, quinoa stems, and quinoa husks) the pyrolysis gas combustion process took place under co-combustion conditions, that is, a constant thermal energy input is required to keep steady temperatures in the combustion and pyrolysis processes. It is observed that the physicochemical properties of the produced biochar changes according to the feedstock and reactor operating conditions. However, in all the cases the molar H/Corg and O/Corg ratios agree with the guidelines for the sustainable production of biochar. It is further observed that the exergy efficiency of charcoal production is around 65.5%. This estimation considers a fully integrated system was the excess thermal energy generated during carbonization is used to produce work (e.g. drying). The reference payback period associated with a pyrolysis facility in Ecuador assuming a biochar price between 3.5 to 5.3 USD/t would range between 3 to 5 years. However, a high uncertainty concerning the biochar market price is recognized. In general, fossil fuel subsidies hinder the transition towards the use of residual biomass as an energy source. Regardless of changes in the subsidies policy, the increase of the exergy efficiency and the optimization of the capital and operation costs associated with the biomass valorization infrastructures are alternatives to promote the sustainable utilization of the residual biomass generated in the studied agro-industrial sectors.

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List of figures

Figure 1.1 A Palm oil mill in Santo Domingo de Los Colorados ... 8 Figure 1.2 Quinoa crops and threshing activities in the highlands of Ecuador. ... 10 Figure 1.3 Cocoa and coffee collection and processing center in the north Ecuadorian Amazon: greenhouse drying units and threshing facilities ... 12 Figure 1.4 Jatropha curcas oil mill in Portoviejo, Manabi. ... 14 Figure 2.1 Human Centred Design (HCD) design kit [165] ... 37 Figure 3.1 Scheme of the proposed energy balance for the pyrolysis and torrefaction processes ... 46 Figure 3.2 Scheme of a pyrolysis process integrated into the quinoa and lupin sector where the excess thermal energy generated is used to drive the drying process or the hot water production process... 59 Figure 3.3 General scheme of the proposed energy system to valorize the residual biomass generated in small-scale oil nut mills. ... 62 Figure 4.1 Estimation of the yields and characteristics of the pyrolytic products of a pyrolysis process that use KS as feedstock under an inert atmosphere. ... 70 Figure 4.2. a) Theoretical estimation of the thermal energy that can be generated as the result of pyrolysis gas combustion and the thermal energy consumption of the KS pyrolysis process. b) The overall efficiency of charcoal production before and after the auto-thermal regime ... 72 Figure 4.3. a) Theoretical distribution of the torrefaction products. b) Theoretical estimation of the thermal energy generated as the result of torrefaction gas combustion and the thermal energy consumption of the torrefaction process... 76 Figure 4.4 Theoretical estimation of the load capacity of a torrefaction process performed at 260 °C under an inert atmosphere, integrating the excess heat from a pyrolysis process and the thermal energy generated by the combustion of torrefaction gas ... 78 Figure 4.5 Theoretical calculation of the energy efficiency associated with an energy system that uses mesocarp fibers and kernel shells as feedstocks to produce biochar and torrefied biomass fuel, respectively ... 79

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vi Figure 5.1 CAD model and scheme of the prototype small and modular auger reactor used in the experiments (P-SMART) ... 95 Figure 5.2 Schematic operation of the pyrolysis gas burner (PGB) ... 97 Figure 5.3 General view of the P-SMART, electronic controls, and monitoring devices. ... 98 Figure 5.4 Scheme of the horizontal biomass burner prototype. Legend: 1. Biomass hopper, 2. Biomass feeder, 3. Air blower, 4. Electric heater for ignition, 5. Infrared flame sensor, 6. Ash removing system, 7. Spring feeding system, 8. Burner frame, 9. Combustion bed, 10. Secondary air and flame stabilization borehole ring, 11. Ash discharge port. ... 99 Figure 5.5 Low-temperature ignition system and ignition protocol in the HBP. Legend: 1. Spring type feeder. 2. Ultraviolet flame detector. 3. Electric heater. 4. Residual biomass (control volume) ... 100 Figure 5.6 Left: the first version of the HBP with a hexagonal combustion bed. Right: the latest version of the HBP with a cylindrical combustion bed ... 101 Figure 5.7 Schematic diagram of the infrastructure used to estimate the axial temperature profile in the flame region. 1. Burner frame, 2. Biomass hopper, 3. Biomass feeder, 4. Air blower, 5. Thermocouple data logger 6. Burner electronic control, 7. Data acquisition, 8. Thermocouple F1, 9. Thermocouple F2, 10. Thermocouple F3, 11. Insulated flanged pipe, 12. Ash discharge port. ... 102 Figure 5.8. Electronic controls of the P-SMART and monitoring devices used during the carbonization. Legend: 1. HBP feeder, 2. HBP hopper, 3. HBP blower, 4. HBP frame, 5. Thermocouple (T1), 6. Thermocouple (T2), 7. Thermocouple (T3), 8. Thermocouple (T4), 9. Thermocouple (T5), 10. Thermocouple (T6), 11. Thermocouple (T7), 12. Rotary vane valve motor, 13. Auger motor, 14. Discharge valve motor, 15 PGB blower, 16. Particle filter, 17. Condenser filter. 18. On line gas analyzer 19. Thermocouple data logger, 20. HBP controller, 21. Pyrolysis controller, 22. Data acquisition ... 103 Figure 5.9 Open source digital airflow meter and considerations for the estimation of the HBP and PGB electric blowers mass flow ... 107 Figure 5.10 Prototypes of the open-source temperature data logger, each of them comprising one Arduino UNO board and four MAX6675 boards adapted to the use of K-type thermocouples ... 108

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vii Figure 5.11 Atomic absorption spectrophotometer provided by the “Instituto Nacional de Eficiencia Energética y Energía Renovable (INER)” to analyze the chemical composition of the ashes produced during the combustion experiments ... 113 Figure 5.12 Palm oil kernel shell (also referred in the literature as palm oil stone), used in the experiments ... 114 Figure 5.13 Quinoa and lupin residual biomass crushed in the hammer mill before the carbonization experiments. Left: quinoa steems. Right: lupin steems ... 115 Figure 5.14 Coffee husks collected in the north Ecuadorian Amazon ... 117 Figure 5.15 Pellet mill of 100 kg/h nominal capacity ... 118 Figure 5.16 Pellet samples produced with different fractions of JCFS, JCSC P-JCSC used for the combustion experiments. From left to right: P1, P2, and P3 (see Table 5.3). ... 120 Figure 5.17 Sawmill wastes (SW) and pruning residues (PR) considered as potential energy sources for the P-SMART initial heating process ... 122 Figure 6.1 Bridging effect: dome or “rathole” formation in the burner hopper during low-density biomass conveying. Fuel in the photo: wood shavings ... 127 Figure 6.2 Low-temperature ignition process of the Jatropha curcas pellets, P1, P2, and P3. Combustion in solid-phase over the burner bed ... 131 Figure 6.3. Temperature profiles observed in the combustion chamber during the combustion process of the biomasses KS, PR, SW, M1, M2, and M3. Excess air rate: 170% ... 133 Figure 6.4. The temperature of the combustion gases at different locations of the flame length along the biomass burner . ... 138 Figure 6.5. Ashes generated during the combustion process of the biomass mixtures M1, M2 and M3 ... 142 Figure 6.6. Up: Sintered ashes collected from the combustion bed during the combustion process of KS. Down: inorganics (stones) that remain in the combustion bed after the combustion process... 143 Figure 6.7. Influence of the excess air rate in the temperature of combustion gases at different locations of the flame length along the biomass burner. Fuel: untreated KS. Excess air rate 100 and 170 % ... 148

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viii Figure 6.8. The axial temperature profile in the combustion chamber corresponding to each stage of the combustion experiments . ... 150 Figure 6.9. Exit flue gas composition during the steady-state period of the KS combustion process. ... 152 Figure 6.10. (A) Temperature profiles observed in the combustion chamber. (B) Temperature profiles observed in the pyrolysis process. Experiment: kernel shell carbonization. Load capacity: 30 kg/h and 50 kg/h. Residence time: 15 min. ... 156 Figure 6.11. Exit flue gas composition observed during the transition from the co-combustion stage to auto-thermal operation in the carbonization of kernel shell. Load capacity: 30 kg/h. Residence time: 15 min ... 160 Figure 6.12. CO concentration calculated according to the European eco-design standards that apply for solid fuel-fired boilers (the limit is less than 500 mg/Nm3_{measured at 11 %} vol. O2). ... 162 Figure 6.13. SEM micrographs of biochar samples prepared from KS under auto-thermal operating conditions at two different load conditions: 30 kg/h (left side) and 50 kg/h (Right side). Residence time: 15 minutes. Carbonization temperatures are shown in Figure 6.10. ... 164

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List of tables

Table 3.1. Specific heat values considered to calculate the sensible heat in the pyrolytic products (char, tar, pyrolytic water, and permanent gas). ... 49 Table 3.2. Average specific heat values of combustion gases considering a reference temperature of 150 °C (423 K) [184] ... 53 Table 3.3. Cost structure used to economically evaluate the implementation of a pyrolysis facility. Minimum costs correspond to large-scale facilities and maximum costs correspond to small-scale facilities [130] ... 56 Table 3.4. Cost structure used to assess the financial performance of a combustion system using KS as fuel to produce thermal energy ... 66 Table 4.1. Proximate and elemental analysis of raw (untreated) KS taken from the field (see Section 1.1.1), and used for the theoretical analysis and the experimental validation. ... 68 Table 4.2. Proximate and elemental analysis of palm moil mesocarp fibers (MF) used to analyze the integrated pyrolysis-torrefaction system ... 75 Table 4.3. Quinoa and lupin weight percentages of residual biomass generated during threshing activities. Data presented on wet basis ... 82 Table 4.4. Proximate and elemental analysis of the residual biomass generated during quinoa and lupin threshing activities. ... 84 Table 4.5. Energetic analysis of the saponins removal processes in the quinoa and lupin sector in Ecuador. ... 85 Table 4.6. Biochar yield (dry basis), exergy destruction rate, and exergetic efficiency of an integrated energy system that produces biochar and thermal energy. ... 87 Table 4.7. Principal financial indicators and thermo-economic index associated with the proposed quinoa and lupin energy system valorization. ... 88 Table 4.8. Financial analysis of a thermal energy production system that aims the replacement of a diesel boiler by a biomass boiler that uses untreated KS as fuel ... 92 Table 5.1. Measurement range and resolution of the infrared gas analyzer used in the experiments ... 110

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x Table 5.2. List of methods used to perform the proximate and elemental analysis of palm oil kernel shell. The kernel shell samples taken from the field does not have salts ... 112 Table 5.3. Blended ratios of the pellets made with residual biomass of Jatropha curcas and the ratio of pruning residues and pellets used in the combustion experiments ... 119 Table 5.4. Blended ratios of the M1, M2 and M3 mixtures that were used in the combustion experiments ... 123 Table 6.1. Proximate and elemental composition of the residual biomasses considered as potential energy sources for the P-SMART’s initial heating process... 129 Table 6.2. Results of the low-temperature ignition tests in the HBP, considering agriculture and wood-derived biomasses as fuels ... 130 Table 6.3. Flue gas composition observed during the combustion experiments of the biomass fuels PR, SW, KS, M1, M2, and M3. ... 136 Table 6.4. Concentration of sodium, iron, calcium, potassium, and magnesium in the bottom ashes (ashes at the grate of the burner) after the combustion experiments of the biomass fuel mixtures M1, M2 and M3 ... 144 Table 6.5. Proximate and elemental analysis the KS samples collected in the field to perform the carbonization experiments and the biochar produced in auto-thermal operation conditions ... 166 Table 6.6. Proximate and elemental analysis the coffee husks samples collected in the field to perform the carbonization experiments ... 169 Table 6.7. Average temperatures observed during the carbonization process of the biomasses CH, QS, and QH ... 171 Table 6.8. Flue gas composition observed during the carbonization experiments of the biomasses CH, QS, and QH. ... 173 Table 6.9. Proximate and elemental analysis the biochar produced during the carbonization of coffee husks (CH), quinoa stems (QS) and quinoa husks (QH) ... 175

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xii

List of publications

This thesis is based on the research work and data discussed in the following scientific papers referred by roman numerals in the text:

i. Heredia Salgado MA, Tarelho LAC, Matos A, Robaina M, Narváez R, Peralta ME. Thermoeconomic analysis of integrated production of biochar and process heat from quinoa and lupin residual biomass. Energy Policy 2017; 114:332–41. doi:10.1016/j.jhep.2009.07.006.

ii. Heredia Salgado MA, Tarelho LAC, Matos A. Analysis of Combined Biochar and Torrefied Biomass Fuel Production as Alternative for Residual Biomass Valorization Generated in Small-Scale Palm Oil Mills. Waste and Biomass Valorization 2018; 9:1–14. doi:10.1007/s12649-018-0467-7.

iii. Heredia Salgado MA, Tarelho LAC, Matos MAA, Rivadeneira D, Narváez C RA. Palm oil kernel shell as solid fuel for the commercial and industrial sector in Ecuador: tax incentive impact and performance of a prototype burner. Journal of Cleaner Production 2018b;213:104–13. doi:10.1016/j.jclepro.2018.12.133.

iv. Mario A. Heredia Salgado, Tarelho LAC, Rivadeneira-Rivera DA, Ramirez V, Sinche D. Energetic valorization of the residual biomass produced during Jatropha curcas oil extraction. Renewable Energy 2019; 146:1640–8. doi: 10.1016/j.renene.2019.07.154.

v. Mario A. Heredia Salgado, Jonathan Coba S, Tarelho LAC. Simultaneous production of biochar and thermal energy using palm oil residual biomass as feedstock in an auto-thermal prototype reactor. Manuscript accepted for publication in the Journal of Cleaner Production (see Appendix II).

Additional disclosure papers (DP), conference articles (CA), conference posters (CP) and technical reports (T) published during the doctoral program and partially overlapping with the papers I to V are:

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xiii DP 1: Mario A. Heredia Salgado, Tarelho LAC. Producción de biochar como alternativa para la valorización energética de la biomasa residual generada en el sector agroindustrial Ecuatoriano: un enfoque participativo. Grupo Español Del Carbón (GEC) 2018; 49:6–11.

CA 1: Heredia Salgado MA, Tarelho LAC, Matos MAA. Valoración del calor residual de reactores de pirólisis para la producción combinada de carbón vegetal y combustible torrificado. Energía 2015; 1:396–404.

CA 2: Rivadeneira-Rivera DA, Ramírez-Peñaherrera VE, Narváez-Cueva RA, Heredia Salgado MA, Tarelho LAC, Matos AM. Co-combustión de pellets de Jatropha curcas (Piñón) con astillas de madera en un quemador horizontal prototipo. EnerLAC - OLADE 2018; 2:8– 23.

CA 3: Rivadeneira-Rivera DA, Ramírez-Peñaherrera VE, Narváez-Cueva RA, Salgado MAH-, Cruz-Tarelho LA da, Matos AMA. Primer análisis de emisiones durante la combustión de pellets de Jatropha curcas a 2635 msnm. Revista Científica Multidisciplinar Investigación Y Saberes 2017; 6:65–79.

CP 1: Mario A. Heredia Salgado, Tarelho LAC, Matos A, Rivadeneira-Rivera D. Palm oil kernel combustion in a prototype furnace in the Ecuadorian sierra region. In: VI Escola de Combustão, Foz Do Iguaçu: UNILA; 2017. doi:10.13140/rg.2.2.36520.88329.

CP 2: Mario A. Heredia Salgado. Thermochemical conversion of agro-industrial waste in small-scale facilities. In: Green Talents Scientific Forum, Berlin, Germany: German Federal Ministry of Education and Research BMBF; 2018. doi:10.13140/RG.2.2.27546.49603.

CP 3: Rivadeneira-Rivera DA, Mario A. Heredia Salgado, Ramirez V, Narváez-Cueva RA, Tarelho LAC, Matos MAA. Primer análisis de emisiones durante la combustión de pellets a 2635 msnm. In: III Seminario Científico Internacional de Cooperación Universitaria para el Desarrollo Sostenible, Latacunga, Ecuador: Red Iberoamericana de Medio Ambiente REIMA; 2017. doi:10.13140/RG.2.2.30437.70886.

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xiv CP 4: Rivadeneira-Rivera DA, Ramírez-Peñaherrera VE, Narváez-Cueva RA, Heredia Salgado MA, Tarelho LAC, Matos AM. Co-combustión de pellets de Jatropha curcas (Piñón) con astillas de madera en un quemador horizontal prototipo. In: Congreso Investigación Desarrollo e Innovación en Sostenibilidad Energética IDI, Quito - Ecuador: Instituto Nacional de Eficiencia Energética y Energía Renovable INER; 2017. doi:10.13140/RG.2.2.23097.67688.

TR 1: Mario A. Heredia Salgado. Política Energética sobre subsidios al diésel y GLP en la agroindustria: análisis termoeconómico de un sistema de valorización de biomasa residual de quinua. Quito - Ecuador: 2015. doi:10.13140/RG.2.2.13660.49287.

TR 2: Mario A. Heredia Salgado. Cuesco de palma africana, un nuevo combustible para uso comercial en Ecuador : análisis económico y evidencia experimental. Quito - Ecuador: 2016. doi:10.13140/RG.2.2.19364.07042.

Finally, there is a set of oral communications (OC) performed in academic events which topics are listed as follows:

OC 1: Transformational research: experiences from the start-up Andes Bioenergy. In: Social Entrepreneurship in Academia, Monterrey, Mexico: Students4Change; 2019.

OC 2: Andes Bioenergy: transformation of small scale agro-industries of developing countries into early stage biorefineries. In: 4th_{Green & Sustainable Chemistry Conference,} Dresden, Germany: Elsevier; 2019.

OC 3: Discussion panel: The International Importance of Sustainability Research and the Opportunities and Challenges Involved. In: Green Talents Scientific Forum, Berlin, Germany: German Federal Ministry of Education and Research BMBF; 2018.

OC 4: Roadmap tecnológico para el uso de cuesco de palma Africana como combustible de uso industrial y comercial en Ecuador. In: Congreso Investigación Desarrollo e Innovación en Sostenibilidad Energética IDI, Quito, Ecuador: Instituto Nacional de Eficiencia Energética y Energía Renovable INER; 2017. doi: 10.13140/RG.2.2.14429.72160

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Honors and awards

During the development of this thesis, the partial results and conclusions, the prototypes design and the potential economic, environmental and social impact associated with the technology developed has been recognized by several Ecuadorian and international institutions. A shortlist of the honors (H) and awards (A) received in these five years of research work is present below.

A1: Award for Entrepreneurial Spirit in Sustainable Chemistry. Elsevier Foundation and International Sustainable Chemistry Collaborative Centre (ISC3): Green Chemistry

Challenge. Dresden, Germany (May 2019). URL:

https://www.isc3.org/en/news/article/article/mario-heredia-salgado-wins-the-first-isc3-entrepreneurial-spirit-in-sustainable-chemistry-award-wi.html

A2: Award for high potential research in sustainable development. German Federal Ministry of Education and Research (BMBF) and German Aerospace Center (DLR): Green Talents Competition 2018. Berlin, Germany (October 2018). URL:

https://www.greentalents.de/awardees_awardees2018_mario-alejandro-heredia-salgado.php

A3: 2nd_{place award in section income, taxes, subsidies and credit in the agriculture sector.} Ecuadorian Ministry of Agriculture and Livestock (MAG): National Research Competition in Agro-economy 2015. Quito, Ecuador (November, 2016). URL: https://es.calameo.com/books/004582932fd70672d05d0

A4: 2nd_{place award in section agricultural technological innovation. Ecuadorian Ministry} of Agriculture and Livestock (MAG): National Research Competition in Agro-economy 2016. Quito, Ecuador (November, 2016). URL: https://www.agricultura.gob.ec/magap-premio-el-trabajo-de-investigadores-ecuatorianos/

A5: Recognition and celebration for Research Advocacy Champions and the critical role of advocacy in research. INASP, HINARI, AGORA, OARE, ARDI, and R4Life: Research

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xvii Advocacy Competition. London, United Kingdom (July 2017). URL:

http://www.research4life.org/wp-content/uploads/2017/07/Layout_Booklet_final_webversion.pdf

H1: Best socio-environmental projects in Latin America. Ecuadorian Ministry of Environment: Premios Latinoamérica Verde. Guayaquil, Ecuador (September 2015). URL: https://www.premioslatinoamericaverde.com/top500/?years=2015&source=post_page---

---H2: Finalist Global Impact Competition Challenge. Singularity University: Global Impact Challenge. Quito, Ecuador (July, 2015). URL: https://ecuador2015.fluidreview.com/

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xviii

Glossary

Abbreviations

CH Coffee husk

HBP Horizontal burner prototype

HHV Higher heating value

KS Kernel shell

LH Lupin husks

LHV Lower heating value

LS Lupin stems

M Biomass fuel mixture

m.a.s.l Meters above the sea level

MF Mesocarp fibers

P Pellets of Jatropha curcas

PGB Pyrolysis gas burner

PR Pruning residues

P-SMART Prototype small and modular auger reactor

QH Quinoa husks

QS Quinoa stems

SW Sawmill waste

USD United States Dollar

Subscripts ch Char db Dry basis F Feedstock fg Flue gas G Permanent gas

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xix hr Heat of reaction L Lost l Latent P Products pg Pyrolysis gas py Pyrolysis R Reactants r Reaction s Sensible t Tar tg Torrefaction gas torr Torrefaction wb Wet basis

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xx

Nomenclature

_Units

Auger pitch cm

Auger rotation speed cm / min

Carbon monoxide concentration in the flue gas mg / Nm3

Overall costs USD / y

Cash flow USD / y

Depreciation rate %

Earnings before taxes and depreciation USD / y

Free cash flow USD / y

ℎ , Water enthalpy of vaporization at reference

temperature T

J / kg W

Initial investment costs USD / y

Income tax %

/ Thermo-economic index USD / y

Molar mass of carbon kg / kmol

Molar mass of hydrogen kg / kmol

Molar mass of water kg / kmol

Molar mass of nitrogen kg / kmol

Molar mass of oxygen kg / kmol

Molar mass of sulfur kg / kmol

Molar mass of water kg / kmol

! Molar mass of air kg / kmol

" Mass kg

ṁ Load capacity of the torrefaction process kg KS / kg MF

! Oxygen concentration in the atmospheric air %vol.

%& Oxygen concentration in the flue gas %vol. % Oxygen concentration according to the eco-design %vol.

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xxi standard

Operating costs USD / y

Operational income USD / y

'' Payback period Y

'( Profit-sharing tax %

)*,+ Latent heat consumed during quinoa drying J / kg

) ,+ Sensible heat consumed during quinoa drying J / kg ) ,, Sensible heat consumed during lupin heating J / kg

- Income from CO2 emissions trading USD / y

- Income from biochar distribution USD / y

- Income from thermal energy distribution USD / y

-% Fuel cost savings USD / y

Temperature °C

.,/ Carbon content in the feedstock kg C / kg F

. ,/ Hydrogen content in the feedstock kg H / kg F

. ,/ Nitrogen content in the feedstock kg N / kg F

. ,/ Oxygen content in the feedstock kg O / kg F

.,/ Sulfur content in the feedstock kg S / kg F

. ,/ Moisture content of the feedstock (mass ratio) Kg W / kg F

. ,+ Initial moisture content of quinoa kg H2O / kg F

.0,/ Ash content in the feedstock kg / kg F

. ,1 Combustion air kg A / kg F

.2& Water content in the pyrolysis gas kg W/ kg F

.3, Stoichiometric air consumption kg A / kg F

.3 Stoichiometric oxygen consumption kg O2 /kg F

. 4,+ Final moisture content of quinoa kg W/ kg F

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xxii

56 Yield of permanent gas kg G / kg F

5 Stoichiometric coefficient kmolH2O / kmolO2

5 Yield of char kg ch / kg F

57 Yield of the pyrolytic product “j” kg j / kg F

52& Yield of pyrolysis gas kg pg / kg F

53, Stoichiometric coefficient kmolO2 / kmolC

53, Stoichiometric coefficient kmolO2 / kmolH

53, Stoichiometric coefficient kmolO2 / kmolN

53, Stoichiometric coefficient kmolO2 / kmolO2

53, Stoichiometric coefficient kmolO2 / kmolS

5 Yield of tar kg t/ kg F

5 Yield of torrefaction gas kg tg / kg F

8 Auger steps -

z Excess air %

9 Exergy content of “a” MJ / y

9 Exergy associated to the biochar MJ / y

9: Exergy destroyed along the process MJ / y

92& Exergy associated to the pyrolysis gas MJ / y

9 Thermal energy that produces work (i.e.

recovered)

MJ / y

;<< Second law efficiency %

=2, First law efficiency of an integrated pyrolysis and torrefaction system

%

= CO2 fraction in the flue gas kmol CO2 / kg F

= H2O concentration in the flue gas kmol H2O / kg F

=< First law efficiency %

= N2 concentration in the flue gas kmol N2 / kg F

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xxiii

= SO2 concentration in the flue gas kmol SO2 / kg F

∆? , Heating value of the pyrolysis products MJ / kg F

∆? ,, Latent heat content in the pyrolysis products MJ / kg F

∆? ,3 Sensible heat content in the pyrolysis products MJ / kg F

∆?@, Heat of reaction in the pyrolysis reactants MJ / kg F

∆?! Thermal energy input MJ / kg F

∆?A, Thermal energy generated within the combustion

process

MJ / kg F

∆?*, Energy lost during the combustion process MJ / kg F

∆?* Energy loss during the pyrolysis process MJ / kg F

∆? , Energy content in the products of the combustion

process

MJ / kg F

∆? Energy content in the products MJ / kg F

∆?@, Energy content in the reactants of the combustion

process

MJ / kg F

∆?@,, Latent heat content in the pyrolysis reactants MJ / kg F

∆?@,3 Sensible heat content in the pyrolysis reactants MJ / kg F

∆?@ Energy content in the feedstock MJ / kg F

∆? Excess thermal energy MJ / kg F

∆? Energy consumed during the pyrolysis process MJ / kg F ∆?@ C ° Thermal energy consumed during torrefaction at

260 °C

MJ / kg F

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1

Preface

According to the intergovernmental panel on climate change, the increase in global mean surface temperature, which reached 0.87 °C in 2006–2015 relative to 1850–1900, has given rise to an increase in the frequency and magnitude of extreme climate weather events [1]. The threat that these extreme climate weather events suppose for humans, their infrastructures, and food production systems, along with other relevant terrestrial ecosystems, has motivated a progressive reduction of greenhouse gas emissions, in particular, those related to energy production processes [2]. In this context, in 2008 the Constitution of Ecuador (chapter No₇₎ established climate change mitigation as a government responsibility encouraging “the promotion of energy efficiency, the development and use of environmental practices and technologies, along with other low-impact renewable energies”. The 2008 Constitution of Ecuador also states that renewable sources should be integrated into the energy matrix observing that “food sovereignty is not jeopardized, ecosystems ecological balance is maintained while caring the population´s right to water” (Art 414) [3].

To accomplish the constitutional mandate, the fourth objective of the Ecuadorian National Development Plan 2013 – 2017 promoted the integration of a higher share of renewable energy into the energy matrix [4]. Accordingly, 2849 MWe were added to the hydroelectric sector completing a total installed electric power of 6010 MWe. On a lower scale, other renewable sources were also introduced into the national energy matrix namely: eolic (21.1 MWe), photovoltaic (27.6 MWe), biomass (144.3 MWe) and biogas (7.3 MWe). Currently, 73.7 % of the electricity demand in Ecuador is covered making use of renewable energy sources [5]. The remaining demand (26.3 %) is still covered by thermal power plants due to grid safety and stability reasons, while the eventual surplus of energy generated in the hydroelectric sector is marketed to the Columbian market [6].

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2 Electricity production resorting mostly to renewable sources is a fact in Ecuador. However, in a broader context, the high demand for liquid fuels is a major concern. The use of liquid fuels of fossil origin namely: diesel (31%), gasoline (28%), fuel oil (8%), LPG (8%) and kerosene (3%), represent 78% of the final energy demand in the country [6]. Diesel consumption signifies almost half (42%) of the total liquid fuels demand [5]. Unlike gasoline, which is mostly demanded by the transportation sector, diesel is also consumed in the industrial, commercial, and agricultural sectors. It is observed that in Ecuador, the small and medium scale agro-industrial sectors have normalized the use of liquid fuels of fossil origin, as diesel and LPG, to produce thermal energy [7]. Although the agro-industrial sector in Ecuador generates 18.3 × 106_{MT of residual biomass per year [8], the linkages between the} liquid fuel consumption and the energetic conversion of the biomass resources generated in the agro-industrial sector has not yet established.

Frequently, the residual biomass produced in small and medium scale agro-industries are left scattered at the field sites or burned in open fires despite the combustion of agricultural wastes in the field sites is forbidden by the Environmental Ministry [9]. When not burned, decomposition of abandoned residual biomass becomes a significant source of methane emissions. Likewise, the residual biomass hoarded at the fields of small and medium scale agroindustries contaminates groundwater through leaching or run-off water, attracts air vector-borne diseases, and gives a non-aesthetic view. Recently, it has been estimated that 41.4% of the diesel consumed in the industrial sector and 89.5% of the industrial fuel oil could be replaced using biomass-derived solid fuels considering processes as thermal energy production in e.g. boilers, burners or furnaces [10]. Thus, the study of alternatives for the energetic conversion of the residual biomass available as a result of agro-industrial processes to generate the thermal energy required by thermal appliances in the industrial, commercial, and agriculture sectors is of major importance.

Traditionally, one of the main reasons for the extended use of liquid fuels of fossil origin in the agro-industrial sector rather than alternative energy sources as biomass has been

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3 attributed to the domestic energy policy that subsidizes the consumption of fossil fuels for small and medium scale industrial consumers [11]. In Ecuador, the local refinery barely covers 55.4% of the total liquid and gaseous fuel demand, and the remaining demand is covered with fuel imports [12]. According to the Ecuadorian energy policy, the official price of the oil derived liquid and gaseous fuels is established monthly by the Agencia de Regulación y Control Hidrocarburífero (ARCH) considering mainly the local production costs. Then, the ARCH based on a presidential decree [13] establishes a set of subsidies to amend the difference between the importation price and the official price. For the case of diesel consumed in the industrial, commercial and agro-industrial sector, the ARCH establishes a differentiated price rate according to the volume of fuel consumed, thus differentiating the large-scale consumers from the medium and small scale consumers. The industrial, commercial, or agricultural consumers that require more than 1500 gallons1_{per month pay a diesel price that does not} consider any subsidy (2.05 USD/gal) while the consumers that require less than 1500 gallons per month pay a subsidized price of 0.90 USD/gal [14]. Besides the subsidies policy, it is important to note that except for the value-added tax (12%), there are no specific taxes applied to the consumption of fossil fuels. As a consequence, the price of oil-derived liquid and gaseous fuels in Ecuador is one of the lowest in South America [15].

In this regard, the government defined a set of tax incentives to promote the implementation of alternative fuels and other alternative energy sources in general. The Organic Law of Internal Tax Regime [16] considers two major tax incentives for the implementation of renewable energy systems: a) a preferential depreciation rate (twice as much as the traditional) for the companies that voluntarily acquire equipment’s, machines and technology for renewable energy production and b) a five-year income tax payment exemption

1_{The unit USA gallons are used in official documents of domestic energy policy to refer the volume of} fuel consumed. Accordingly, this thesis refer the unit USA gallons rather than, the international unit litters (1 gal = 3.79 L)

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4 for the companies that make new and productive investments out of the urban sector (Quito and Guayaquil) especially in the renewable energy sector and emphasizing biomass-derived energy production. Nevertheless, the offer of technology for the energetic conversion of agro-residues in small scale facilities is scarce in the domestic market. Thus, the influence of current tax incentives in the promotion, implementation, and use of renewable energy sources is still uncertain.

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5

Chapter 1:

Introduction

The structure of the agro-industrial sector in Ecuador is linked to its geography. The presence of the Andean mountain range divides the continental Ecuador in three regions, namely: highlands, amazon, and coastal to which is added the insular region (the Galápagos Islands). The significant altitude differences between the highlands and the rest of the regions result in biodiverse ecosystems where various types of products are grown and industrialized. Accordingly, the agro-industrial sector is diverse and dispersed between all these four regions. For a few large-scale agro-industrial facilities as the sugar cane, for example, residual biomass to energy conversion is recognized as a waste management strategy. Just behind the hydroelectric sector, the sugar cane sector in Ecuador is the second producer of electricity from renewable sources with a total installed capacity of 144.3 MWe [17].

The sugar cane sector claims that there is enough installed capacity to increase electricity production even using residual biomass generated in other agro-industrial sectors, for example, palm oil, rice, cocoa, corn, coffee, or banana. Nonetheless, it is observed that the domestic energy policy restrict the maximum amount of power that can be purchased from the biomass thermal power plants of the sugar cane sector [18, 19] mainly because the electricity production costs of the sugar cane sector are higher regarding those of the hydroelectric sector [20, 21]. Hence, the energetic valorization of residual biomass from other agro-industrial sectors in the already existing biomass thermal power plants of the sugar cane sector is somehow limited. In this context, the study of technological alternatives that allow the energetic conversion of residual biomass generated in the small and medium scale agro-industrial sector is of major relevance. This study describes four different agro-agro-industrial activities from the four Ecuadorian regions in which alternatives for the energetic conversion of the residual biomass generated were studied.

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6 1.1A brief characterization of the four agro-industrial sectors analyzed in this thesis

1.1.1The palm oil sector: palm oil mills in the Ecuadorian midlands

In Latin America, Ecuador is the second palm oil producer behind Colombia. Unlike Colombia, where the total palm oil cultivated area (483733 hectares) associates barely 5000 farmers, the palm oil sector in Ecuador with almost half the cultivated area (280.000 hectares) groups more than 7000 farmers of which 87% own less than 50 hectares [22, 23]. Hence, besides the importance of the palm oil sector in the Ecuadorian industrial matrix, it is also considered as of especial social interest [24]. This more equitable distribution of arable land in the Ecuadorian palm oil sector has influenced the way the agro-industrial processing is performed.

Unlike the often referred in the literature about the palm oil sector, the palm oil extraction process in Ecuador is not performed in large scale facilities. In general, the agroindustrial processing of palm oil in Ecuador is divided into two stages that are performed in small-scale facilities that are not necessarily integrated into the same location. In the first stage of processing, the palm oil is extracted in the so-called oil mills. The oil mills collect and process the fresh fruit bunches. Then, in a second stage, the nuts that result from the pressing process are transported from the oil mills towards other facilities to be processed into palm kernel oil. Although the oil nut mills are in the same region, they are usually located several kilometers away from the oil mills. The most recent estimates show that there are forty small scale palm oil mills and around six small scale oil nut mills operating in Ecuador [22]. There are very few cases of facilities with the capacity of processing simultaneously the fresh fruit bunches and the nuts. Thus, the agroindustrial processing of palm oil in which the fresh fruit bunches and the nuts are processed in separated small-scale facilities is predominant. This type of agroindustrial processing in which the fresh fruit bunches and the nuts are processed separately have been also observed in some countries in Africa [25, 26].

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7 Although for the producing countries as Ecuador, palm oil is an important source of economic growth, the environmental and social impacts associated with its cultivation and processing should be also highlighted. One of the major concerns has to do with the uncontrolled expansion of the agricultural frontier which results in a significant biodiversity loss due to the permanent conversion of tropical forest into cropland [27, 28]. It is also stated that the development of the palm oil sector has triggered conflicts over land tenure rights in local communities. Moreover, the wastes generated during palm oil harvesting and post-harvesting operations are recognized as a significant source of soil, air, and water pollution [29]. To prevent tropical forest deforestation, the sustainability standards promoted by the Roundtable on Sustainable Palm Oil (RSPO) have committed the stakeholders throughout the palm oil supply chain including governments, to restrict any future expansion of palm oil agriculture to pre-existing cropland or degraded habitats [30]. However, control over the expansion of the palm oil crop may not be enough to prevent the arising environmental impacts derived from wastes' final disposition.

It is estimated that the residual biomass production rate is around twice the amount of crude palm oil produced [31]. The industrial facilities related to the Ecuadorian palm oil sector have been trying to valorize the residual biomass generated during the extraction process. Currently, a fraction of the mesocarp fibers (MF) and kernel shells (KS) generated during the oil nut extraction process are used as fuel in low-efficiency boilers to produce process steam which makes the mills self-sufficient in terms of thermal energy [22]. The fraction of KS that is not burned is usually sold as a soil covering in gardening operations and a sporadic utilization of the KS as fuel in the cement industry has been also identified. Traditionally, the empty fruit bunches (EFB) were dumped on land for biodegradation. Nevertheless, some oil mills started using them as feedstock for compost production. Moreover, the pressed cake that results after the sterilization and digestion processes is currently used to produce animal feed. Regardless of these valorization initiatives, it is estimated that the residual biomass generated by the

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8 Ecuadorian palm oil sector and that is available for other uses is: 5×106_{t/year of EFB, 3.1×10}6 t/year of MF and 1.2 ×106 _{t/year of KS [8].}

Figure 1.1 A Palm oil mill in Santo Domingo de Los Colorados

In tropical regions as Ecuador, the non-seasonal character of the palm oil crop makes the residual biomass generated available in a single location throughout the year (i.e. the mills), which is an advantage for the potential establishment of residual biomass valorization infrastructures. Accordingly, the development of technology alternatives that allow a proper integration and optimal use of the residual biomass generated in the palm oil mills may be an alternative to mitigate the associated environmental impacts, improve the mill's competitiveness while strengthening the income of the associated peasant population.

1.1.2The quinoa and lupin sector: post-harvesting facilities in the Ecuadorian highlands

Quinoa and lupin are native pseudo cereals from South America highlands which have been cultivated for thousands of years by peasant communities in Ecuador, Peru, and Bolivia. Quinoa and lupin crops are recognized as relevant protein sources which cultivation promotes local food security, community empowerment, poverty reduction, and local resources conservation [32]. The quinoa grains have an outstanding protein content that ranges in amounts from 7.4 to 22.1 wt%. Quinoa protein is of relevant quality due to the presence of sixteen essential aminoacids [33, 34]. Furthermore, the quinoa grain is gluten-free, owns high

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9 content of fiber, health-beneficial phytochemicals, including amino acids, fiber, polyunsaturated fatty acids, vitamins, and minerals [35]. Regarding the lupin nutritional properties, the high protein content that ranges from 41 to 51wt% is highlighted along with the presence of complex aminoacids, for example, lysine and leucine. The lupin protein content is almost double when compared to traditional legumes and grains and higher than soy protein content [36]. Likewise, lupin fat content ranges from 14 to 24 wt% which is higher than cotton and soy oil seed content and in the same level of other popular oleaginous [37, 38].

In recent years, quinoa and lupin crops have increased in the producing countries due to the high demand for the food and pharmaceutical products that can be derived from the grain [39]. The outstanding quinoa and lupin properties and the wave of interest in “superfoods” in wealthy countries, made that in less than a decade quinoa and lupin that were largely unknown outside South America, to be an upper-class staple in Europe, the United States and elsewhere. Nonetheless, the quinoa and lupin commercial success have resulted in soil over-exploitation, intensive use of fertilizers, and biodiversity loss due to the conversion of typical highlands eco-systems into cropland [40]. Furthermore, the loss of soil fertility and decrease of soil organic matter content has resulted in a significant decrease in the quinoa and lupin grain protein content, which is devaluing its market value [41].

In Ecuador, most of the available data regarding quinoa and lupin sectors, namely: growing, harvesting, post-harvesting, and industrial operations are scattered between local universities, NGO´s and research institutes, thus, references and information published in research journals are scarce [42–44]. According to Peralta et al, quinoa and lupin growing are reported to require 570 and 192 kilograms of synthetic fertilizer per hectare respectively, while quinoa and lupin organic production requires 5-10 tons of organic fertilizer per hectare [42]. After growing, a significant generation of residual biomass is reported during post-harvesting operations, which are mostly performed under a de-centralized model. It is reported that some of the residual biomass generated during post-harvesting operations is re-incorporated in soils, used as cooking fuel or animal breeding. Nonetheless, there is no data to support a

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10 proper quantification of the residual biomass generated with respect to the grain produced, neither basic aspects as the definition the heating value or elemental and proximal composition.

Figure 1.2 Quinoa crops and threshing activities in the highlands of Ecuador.

The industrial processing of lupin and quinoa for saponins removal is reported to consume thermal energy intensively. However, there is no theoretical, experimental neither empirical estimation of the specific thermal energy required by the saponins removal processes. It is stated that diesel and LPG (both highly subsidized by the government) are typically used to produce the thermal energy required by the quinoa and lupin processing facilities [45, 46]. Accordingly, the quinoa and lupin sector is particularly dependent on subsidies to fossil fuels. The quinoa and lupin threshing wastes have been managed as of low economical interest. Thus, the link between the residual biomass generated during the post-harvesting operations, the fertilizer consumption, and the thermal energy consumed during the quinoa and lupin industrial operations is still poorly understood.

According to Kammann et al, the integration of pyrogenic carbon produced from quinoa residual biomass to the soils may alleviate the organic matter lost, improve the plant growth and eco-physiological response while increasing drought tolerance [47]. Likewise, the quinoa plants growing in biochar-amended soil showed higher nitrogen concentrations in the

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11 leaf. Hence, the application of biochar during quinoa growing may improve grain quality. Complementarily, the thermal energy generated in excess during the carbonization process could contribute to reducing the consumption of fossil fuels during the saponins removal processes. In this context, the study of the energetic conversion of quinoa and lupin residual biomass is of relevance as it can support the sustainable growth of these sectors, promote the sustainable consumption of its derived products and continue being a source of income for local communities.

1.1.3The cocoa and coffee sector: small scale collecting and processing centers in the Ecuadorian Amazon

From the '70s, the tropical rainforest of the Northern Ecuadorian Amazon (NEA) has received a large influx of migrant families which resulted in an extensive colonization phenomenon. The ever-increasing population has been mostly dedicated to agricultural activities which have resulted in tropical forest deforestation due to forest conversion into permanent cropland. Currently, the NEA is a complex fabric due to interactions between the oil industry, biodiversity, agricultural production, and the continuously growing human settlements. Although this area is endowed with vast quantities of natural resources (oil, biodiversity, water), the NEA performs poorly in terms of socio-economic indicators. For instance, the extreme poor were of 40.8% of the total population in 2011, as opposed to the national average of 11.6%. Unlike other regions in South America where land concentration is the norm, the NEA region is characterized by a high land distribution. The average farm's size is between 20 and 30 ha, which is considered the optimal size for a household to generate income in the regional context. However, the lack of basic infrastructure, public services, and access to international markets have resulted in a strong dependence of NEA smallholder peasants on government subsidies and government initiatives [48].

In the NEA, combined cultivation of Robusta coffee (Coffea canephora) and cocoa (CCN51 and Theobroma cacao) has been predominant. Likewise, a sustained increase in palm

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12 oil crops has been observed in recent years. Unlike the national cocoa that is classified as “fine aroma” and is used in the manufacture of high-quality chocolate and mixtures, Robusta coffee produced in the NEA has a low market value. Nonetheless, Robusta coffee has managed to stay in the coffee market due to it is often blended with Arabica coffee to increase the caffeine content and improve the coffee body [49]. Through the popular and solidarity economy law, the government and several international aid agencies have focused their action on the reactivation of cocoa and coffee production, the strengthening of cooperatives and associations along with the support of the commercialization processes. Accordingly, peasants and smallholders have been associated in emergent cooperatives that have given rise to collecting and processing centers for the communal management of post-harvesting operations.

Figure 1.3 Cocoa and coffee collection and processing center in the north Ecuadorian Amazon: greenhouse drying units and threshing facilities

In the collection and processing centers, the harvested coffee cherries are dried using sun radiation to about 10-11% moisture content on clean drying yards or greenhouse craft dryers. Proper drying contributes to the coffee quality regarding color, shape, and aromatic constituents. The coffee cherries normally get fully dried in 3 to 4 weeks under bright weather conditions [50]. Tropical regions as the NEA are characterized by a heavy rainfall season comprising the end of December and may last until the end of April. Accordingly, during the rainfall season (and in cloudy months) the coffee drying process is done using low-efficiency industrial dryers that typically run on LPG or diesel. The collection and processing centers

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13 studied use the dry method for coffee cherries processing. Hence, the coffee beans are separated by removing the different shell layers in a threshing machine. On average, the coffee husk produced during coffee beans threshing represents about 12 wt% of the cherry on a dry weight basis. Thus, 0.18 tons of husk is produced per each ton of coffee cherry [51].

It is stated that coffee wastes and by-products constitute a source of severe contamination due to its content of caffeine, free phenols and tannins (polyphenols), and pose serious environmental problems leading to water and land pollution around collection and processing centers [52]. In the NEA and other coffee-producing countries (e.g. Colombia, Indonesia, Vietnam, Brazil) large scale utilization and management of coffee wastes remain a challenge. The coffee husk generated during threshing operations has limited applications as fertilizer, livestock feed, or compost. Frequently, coffee husks are dumped on land for biodegradation or burned in open fires, which have been associated with significant methane and carbon monoxide emissions. In recent years, its use as fuel for direct combustion to generate the thermal energy required by the coffee drying processes has been promoted as an alternative to decrease energy costs. However, coffee husk combustion has been associated with the release of harmful emissions due to improper or incomplete combustion [53]. Furthermore, severe ash accumulation, slagging, fouling, and corrosion have been reported during coffee husk combustion [51]. Accordingly, the study of proper alternatives for the energetic conversion of coffee husks is a current need.

1.1.4Jatropha curcas oil use as diesel replacement in the Galápagos Islands: oil mills in the Ecuadorian coast

The Galapagos Islands, declared world heritage in 1979 [54, 55], are an archipelago situated in the Pacific Ocean at 973 km from the Ecuadorian coast. Traditionally, electricity production for the Archipelago rural and urban areas was accomplished using gensets that run on diesel, which is transported by ships from the continental territory. In 2001, a tragic event during a fuel transportation operation caused the spill of 145.000 gallons of diesel and