Assessment of the Implementation of Alternative Process Technologies for Rural Heat and Power Production from Cocoa Pod Husks
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Assessment of the implementation of alternative process technologies for rural heat and power production from cocoa pod husks Dimitra Maleka Master of Science Thesis KTH School of Industrial Engineering and Management Department of Energy Technology Division of Heat and Power Technology SE-100 44 STOCKHOLM Master of Science Thesis EGI 2016: 034 MSC EKV1137 Assessment of the implementation of alternative process technologies for rural heat and power production from cocoa pod husks Dimitra Maleka Approved Examiner Supervisors Reza Fakhraie Reza Fakhraie (KTH) David Bauner (Renetech AB) Commissioner Contact person ii Abstract Cocoa pod husks are generated in Côte d’Ivoire, in abundant quantities annually. The majority is left as waste to decompose at the plantations. A review of the ultimate and proximate composition of CPH resulted in the conclusion that, CPH is a high potential feedstock for both thermochemical and biochemical processes. The main focus of the study was the utilization of CPH in 10,000 tons/year power plants for generation of energy and value-added by-products. For this purpose, the feasibility of five energy conversion processes (direct combustion, gasification, pyrolysis, anaerobic digestion and hydrothermal carbonization) with CPH as feedstock, were investigated. Several indicators were used for the review and comparison of the technologies. Anaerobic digestion and hydrothermal carbonization were found to be the most suitable conversion processes. For both technologies an analysis was conducted including technical, economic, environmental and social aspects. Based on the characterization of CPH, appropriate reactors and operating conditions were chosen for the two processes. Moreover, the plants were chosen to be coupled with CHP units, for heat and power generation. After the evaluation and calculation of the main products and by-products that can be obtained, an economic analysis was conducted. Most of the electricity was assumed to be sold to grid (0.10 USD/kWh), after self-utilization, and the by-products were assumed to be sold as bio- fertilizers or soil conditioners, in both cases. The prices suggested for the by-products were estimated based on their nutrient content. For the economic analysis, total investment costs, running costs, revenues and more economic indicators were obtained and calculated. Both case study plants were found to be economically feasible (NPV>0). After comparing the NPV values, hydrothermal carbonization had higher NPV value, meaning it is more profitable. Though, there are many more barriers to overcome for hydrothermal carbonization than for anaerobic digestion. Moreover, the two case study plants can help with GHG mitigation, since 1,760 - 1,980 tCO2 eq/year can be avoided. Furthermore, several social benefits were identified. In conclution, hydrothermal carbonization and anaerobic digestion plants, utilizing CPH for energy conversion are feasible and cost viable solutions. Although, the governmental support can reduce the risks by assisting in the promotion of the by-products markets. Keywords: Cocoa pod husk, anaerobic digestion, hydrothermal carbonization, techno- economic feasibility, biogas, hydrochar, bio-fertilizers. iii ACKNOWLEDGEMENTS I would like to start by expressing my sincere appreciation and gratitude to my parents and sisters, for their continuous love, encouragement and support in all possible ways during all stages in my life. I would not be able to be here and do this work if they were not there to support me. My deepest gratitude and appreciation to my thesis supervisors, Reza Fakhrai from KTH and David Bauner from Renetech AB, for their continuous guidance, support and the opportunity they gave me to learn from their experience during my master thesis. My special gratitude is extended to Bahram Saadatfar from KTH and Tom Walsh from Renetech AB for their constant help and support during this work. Additionally, special thank you to David Bauner and Tom Walsh for giving me the opportunity to work with the particular project, and along with Kjell Andersson, for always providing feedback on my work during my monthly presentations to them. Moreover, I would like to particularly thank Reza Fakhrai and Bahram Saadatfar for discussing with me and providing their opinion, whenever I needed them. Special thanks also, to all the people in the office, for always being good and supportive to me and for sharing many laughs during our daily brake. Finally, I would like to express my profound appreciation and gratitude to all my friends that encouraged and supported me through my master studies, and especially to my best friend for being next to me and supporting me in every possible way every day. iv List of acronyms ANARÉ Autorité Nationale de Régulation du Secteur de l’Électricité (National Regulatory Authority of the Electricity Sector) BDC Biodegraded Carbon C Carbon C/N Carbon to Nitrogen ratio CCS Carbon Capture and Storage CDM Clean Development Mechanism CH3COOH Acetic acid CH4 Methane CHP Compined Heat and Power (or co-generation) CIE Compagnie Ivoirienne d’Électricité (Ivorian Electricity Company) CIPREL La Compagnie ivoirienne de production d'électricité (Ivorian Company for electricity generation) Centre de Coopération Internationale en Recherche pour le CIRAD Développement (Agricultural Research Centre for International Development) Cl2 Chlorine Centre National de Recherche Agronomique (National Centre for CNRA Agronomic Research) CO Carbon monoxide CO2 Carbon dioxide CPH Cocoa Pod Husk(s) CSTR Continuous stirred-tank reactor Daf Dry ash free Deutsches Biomasseforschungszentrum (German Biomass Research DBFZ Centre) DC Direct Costs DCB Dry Cocoa Beans ECI Economic Complexity Index ECN Energy research Centre of the Netherlands ECOWAS Economic Community Of West African States EL Electricity eq Equivalent F Fibrous digestate FAO Food and Agriculture Organization GDP Gross Domestic Product GHG Greenhouse Gas Emissions H Hour H Hydrogen H2S Hydrogen sulfide Ha Hectare(s) HHV Higher Heating Value HRT Hydraulic Retention Time HTC Hydrothermal Carbonization HTCB HTC biochar v HTG Hydrothermal Gasification HTL Hydrothermal Liquefaction IC Indirect Costs ICCO International Cocoa Organization IDH Initiatief Duurzame Handel (Sustainable Trade Initiative) IEA International Energy Agency IPCC Intergovernmental Panel on Climate Change IPP Independent Power Producer IRENA International Renewable Energy Agency IRR Internal Rate of Return ktoe Kilotonne of oil equivalent L Liquid digestate LCOE Levelized Cost of Electricity LHV Lower Heatiing Value Mtoe Million Tonnes of Oil Equivalent N Nitrogen n.d. No date NH4-N Ammonium NPK Nitrogen - Phosphorous - Potassium NPV Net Present Value N-tot Total Nitrogen O Oxygen O&M Operation and maintenance ODM Organic Dry Matter OLR Organic Loading Rate PBT Payback Time PEC Purchased equipment costs ppm Parts per million PW Process water R&D Research and Development S Sulfur SOx Sulfur oxides STP Standard Temperature and Pressure t Ton TIC Total Investment Costs TLV Threshold Limit Value TOC Total Organic Carbon TPES Total Primary Energy Supply TRL Technology Readiness Level TS Total solids USD United States Dollar VAT Value-added Tax VS Volatile solids WCF World Cocoa Foundation wt% % of weight vi Contents Abstract .......................................................................................................................................................... iii ACKNOWLEDGEMENTS ..................................................................................................................... iv List of acronyms ............................................................................................................................................ v List of tables .................................................................................................................................................. ix List of figures ................................................................................................................................................. x 1. Introduction .......................................................................................................................................... 1 1.1. Objective of the thesis ................................................................................................................ 4 1.2. Thesis outline ............................................................................................................................... 4 1.3. Scope and Limitation of the study ........................................................................................... 5 1.4. Introduction of the company .................................................................................................... 5 2. Cocoa pod husks - Literature review ................................................................................................ 6 2.1. Studies on Cocoa Pod Husks .................................................................................................... 6 2.2. Cocoa pod husks characteristics ............................................................................................... 7 3. Côte d’Ivoire ......................................................................................................................................... 9 3.1. Background of the country ........................................................................................................ 9 3.2. Agriculture in Côte d’Ivoire....................................................................................................