Proceedings of the International Society of Cane Technologists, volume 30, 1595–1602, 2019

Peer-reviewed paper

Sugarcane energy: potential electricity production from vinasse produced by the industry

Joaquín Mario Ortiz and Luis Erazzú

Instituto Nacional de Tecnología Agropecuaria (INTA), Argentina; [email protected]

Abstract Tucumán is Argentina's largest producer of bioethanol from . The main effluent of the process is vinasse, a liquid with a COD and BOD hundreds of times higher than allowed by the authorities for disposal into a waterbody. Currently, the vinasse is irrigated onto sugarcane fields or used for composting. During 2017, Tucuman produced almost 300,000 m3 of ethanol and 3,600,000 m3 of vinasse. Two theoretical models were proposed to take advantage of the vinasse. The first uses concentrated vinasse and as auxiliary fuel to be burnt in a boiler. The second one consists in generating biogas from vinasse using the methodology used by the FAO in the 2016 Wisdom Analysis for Tucumán and adjusting it according to local industries’ criteria. Both models calculate the energy provided to generate electricity, the first one using the heat generated by combustion to operate a turbine and the second using the biogas in internal combustion engines. The price for 1 MWh was the one awarded in RenovAr 2.0 (Argentina’s national promotion for the use of sources of renewable energy to generate electric power). The 3 study shows that 69 Mm CH4/year could be produced to provide 282 GWh using internal combustion engines with a gross income of USD43,000,000/year and vinasse could be concentrated to provide 342 GWh using turbines to obtain ash rich in potassium, with a mixed gross income of USD49,000,000/year. Due to the huge volume of vinasse produced every year in Tucumán and the significant cost that a proper handling imposes on the distilleries, an alternative disposal is required. It should include an option capable of generating an economic income. Due to the high investment required for the concentration and combustion of vinasse, this technology is suggested for distilleries with a production greater than 70,000 m3 ethanol/year, while biogas generation is recommended for smaller ones.

Key words Sugarcane, vinasse, energy, sustainable, environment

INTRODUCTION

Tucumán is the smallest province in Argentina (22,524 km2) but it has the greatest population density (64 inhabitants/km2). The main economic activity is the sugarcane industry (10% of its GDP). According to the CAA (Argentinian Sugar Center) and IPAAT (Tucumán Institute for the Promotion of Sugar and Alcohol), Tucumán generates 64.5% of Argentina’s sugar production and around 300,000 m3 ethanol/year (more than 60% of Argentina’s ethanol production from sugarcane).

Producing 1 L of alcohol 96° generates 10-15 L of vinasse (Ferreira and Monteiro 1987). Vinasse is a residue rich in organic matter, potassium, calcium, magnesium, sulfur and nitrogen. I t has a brown color and a pH of 3.5-5 (España-Gamboa et al. 2011). The chemical composition of vinasse can change according to the technology used during distillation, soil characteristics and origin of the fermentable base (if it comes from or ). Averages and variation of vinasse composition for the sugarcane alcohol industry in Tucumán are given in Table 1 (Provincial Commission of Vinasse 2009).

Production of vinasse has increased during the last decade due to two National Laws: 26,093 of regulation and promotion for the sustainable use biofuels (2006) and 26,334 of production of bioethanol (2007). These laws set an obligatory percentage of 12% of bioethanol in gasoline. Argentina has been promoting the generation of electricity from renewables energies since 2016 through a regulation called RENOVAR supported by national laws. This requires that renewable energies in the energy matrix should increase from 2% to 20% between 2016 and

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2025. For this, different bid rounds were made in which the Word Bank guarantees payment in US dollars for the different energy investments.

Table 1. Physical-chemical parameters and mineral contents in Tucumán vinasse.

Composition / physical-chemical parameters Average Range pH (25°C) 5.10 4.8-5.4 Conductivity (25°C) (mS/cm) 26.54 24.1-28.7 BOD (mg O/L) 98,753 90,000-110,000 COD (mg O/L) 42,940 32,000-54,000 Relation BOD/COD 0.43 0.29-0.60 Moisture (%) 90.20 89-92 Calcium (%) 0.22 0.16-0.25 Magnesium (ppm) 636 532-880 Sodium (ppm) 1,048 554-1,800 Potassium (%) 1.49 1.21-1.82 Zinc (ppm) 2.90 1.00-3.00 Copper (ppm) 4.10 3.5-6.7 Manganese (ppm) 10.20 7.8-12.7

Argentina is a potassium importer; in 2017 Argentina imported 45,657 t of potassium fertilizer and 28,067 t were potassium chloride (KCl) (Chamber of the Argentine Industry of Fertilizers and Agrochemicals). Given the high potassium content of the vinasse, the production of fertilizer looks attractive and this could improve the trade balance and even allow export to large consumers of KCl such as Brazil.

Treatment and final disposal of vinasse is a challenge because of its high Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD) hundreds of times greater than the limit set by SEMA (Tucumán’s Environmental Secretary). Thus, the distilleries must dispose of the vinasse but avoid environmental pollution. Currently, there are two main ways of disposing of vinasse: ferti-irrigation and composting.

Irrigating the vinasse is the most used method. However, Tucumán’s soil is rich in potassium, so the areas in which vinasse can be irrigated as potassium fertilizers are limited (Morandini 2010). Vinasse dose depends on its composition (content of K2O and electric conductivity), the soil’s cation exchange capacity (CEC), the soil’s content of K, P and N, aquifer depth and the percentage of organic matter (Fadda and Morandini 2007). SEMA allows a maximum dose of 150 m3/ha/year of raw vinasse (from molasses) in sugarcane crops. Vinasse should be diluted in water at 1:10 to 1:30 (Morandini and Quiaia 2013). In a soil of the non-saline alluvial plain of Tucumán, Portocarrero et al. (2018) and Hernandez et al. (2018) observed changes in salinity and microbial populations due to repeated raw vinasse application.

Composting has been practiced in Tucumán by Compañia Azucarera Los Balcanes S.A and Ingenio Leales. The first one concentrates the vinasse from 10 to 25-30 Bx and sprinkles it over bagasse or sludge. The final product is compost that can be used directly in fields or in greenhouses.

There are other solutions for the final disposal of vinasse; production of energy and production of fertilizer. Two options have been proposed: produce biogas from vinasse, or concentrate it and burn it in a boiler.

In biological reactors, raw vinasse enters the bioreactor and by microbiological action in an anaerobical environment produces carbon dioxide (CO2), biogas and treated vinasse. The pH rises from 4.5 to 7, balances the carbon/nitrogen ratio and reduces the organic load of the effluent. In Tucumán, La Trinidad distillery has built an Upflow Anaerobic Sludge Blanket (UASB) biodigester to treat 5% of its vinasse (personal communication B. Acorroni). The National Institute of Agricultural Technology (INTA) has installed a bio digester in its facility at Famaillá, Tucumán, with the collaboration of BIOTEC in order to study the behavior of the bio digested vinasse as a fertilizer.

Use in boilers consists of concentrating the vinasse from its usual concentration from 11 to 60 Bx and injecting that into the boilers for direct combustion. It needs a supplementary fuel, usually bagasse in a proportion not lower than 30%.

Our objective was to determine the potential of energy production, by taking advantage of the vinasse generated by the ethanol industry in Tucumán province. Two theoretical models: Biogas generation and vinasse combustion,

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in both cases as fuel for electricity generation, were analyzed. Other benefits that emerge from the proposed models are also analyzed.

MATERIALS AND METHODS

Concentration and combustion of vinasse

Vinasse concentration is increased from 11 to 60 Bx by using multiple effect evaporators. This allows injecting the concentrated vinasse (Lower Calorific Value (LCV) ~1,850 kcal/kg) directly into the boiler. A calorific supplement such as bagasse is needed (with 50% moisture has a LCV~1650 kcal/kg; Ortiz 2018).

The heat obtained could produce enough steam to drive a turbo generator to generate and supply electricity into the national grid. Combustion gasses are filtered by electromagnetic dry cyclones and the solid fraction is separated from the CO2 and the other gases which are released by the chimneys. Ash from the concentrated vinasse has 42-43% K2O and 9-10% P and is separated into a different hopper than the ash from the bagasse.

The output steam (with lower pressure) recirculates through a heat exchanger and re-enters into the boiler as condensed water to re-initiate the cycle.

In 2018 the production of ethanol in Tucumán was 299,086,206 m3 (between April 2017 and April 2018). Given an average of 12 L of vinasse per 1 L of ethanol and the water evaporated at different concentrations according to Perera (2009) it would be possible to produce 663,971 m3 of vinasse with 60 Bx each year in Tucumán. This system requires at least 30% of a calorific supplement such as bagasse with 48-52% moisture according to ISGEC (2018).

Biogas generation

There are mainly two models to produce biogas from vinasse on an industrial scale:

Up flow Anaerobic Sludge Blanket (UASB) is the most widespread kind of biodigester in the world. There are no UASBs working with vinasse in Argentina at an industrial scale, with the exception of La Trinidad’s experience which only works with a low volume and it vents the biogas produced.

Horizontal Flow Anaerobic Digester (HFAD) consists of a pond covered by a bell of high-density polyethylene (HDPE). The effluent flows horizontally across the pond in a continuous process of biogas generation.

Escartín et al. (2016) determined that sugar manufacture generates 45 kg of molasses/t cane. This could generate 12 L of ethanol and 0.13 m3 of vinasse. Considering a production of 12,675,458 t sugar cane in 2014, the potential 3 methane (CH4) production is 44,985,200 m CH4/year. Our theoretical model follows the same methodology but the input values were adapted slightly for the local industry’s values (see Annex). Our results show an increase in the CH4 production because their methodology considers the production of ethanol only from molasses (12 L ethanol/t cane), whilst we considered sugarcane juice extracted in the mills (85 L ethanol/ t cane) (Anschau et al. 2011).

For the following calculations, the average COD of the vinasse was adjusted to 98.753 kg/m3 and the BOD to 42.94 kg/m3 according to the values published by the Provincial Commission of Vinasse in 2009.

The analysis considers using the methane produced to run Internal Combustion Engines (ICE) and to produce electricity or using it to evaporate the treated vinasse and obtained a solid biofertilizer with the advantage of having no effluent at all.

RESULTS AND DISCUSSION

Model a

With a supply of 663,971 m3 vinasse at 60 Bx and 199,191 t bagasse at 50% moisture, a 56.75 MW plant should work for 250 days, with a plant efficiency of 20%. According to the World Bank data the average electricity use in Argentina was 3,052 kWh per capita in 2014. This, then, is enough to cover 112,000 families’ electricity annual

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consumption. The annual gross income from selling the electricity would be about USD36.3 million/year (Annex I).

The concentered vinasse ash production would be 59,000 t/year. According to the commodity price in USA for KCl and hydroxyapatite (Ca5(PO4)3), the value of this by-product should be of around USD12.8 million/year (Annex II).

The annual total income of this system should achieve USD 49.1 million/year.

Model b

An annual ethanol production of 299,086,206 m3 and 3,589,034 m3 of vinasse at 11.1 Bx would generate around 3 69 million m CH4/year (Annex III).

Considering the methane production calculated and a LCV of 9000 kcal/m3, an Internal Combustion Engine (ICE) with an efficiency of 39% could supply a plant of 47 MW for 250 days (enough to cover 92,000 families’ electricity annual consumption).

Considering a price of USD153/MWh (adjudicated by RENOVAR to a similar project in Tucumán that produces electric energy from biogas), it would be possible to generate a gross income of USD43.1 million/year (Annex IV).

Alternatively, the biogas could be used to generate enough heat to evaporate and dry the treated vinasse (zero effluent) and obtain a bio-fertilizer rich in potassium and humus. This process requires two stages: the first one uses a multiple effect evaporator and in the second one where concentrated vinasse is spread through a spray drier. This technology would generate 146,000 t bio fertilizer at 20% K2O/year with 5% moisture and a theoretical market value of USD29.2 million/year (Annex V).

Comparison between proposed models and vinasse ferti-irrigation

Table 2 summarizes the analysis and calculations made in models “a” and “b” and comparing them to vinasse ferti- irrigation. The presence of effluents, gross energy and ash produced, as well as the gross income are shown. Advantages and disadvantages are also displayed.

Table 2. Comparison between proposed models and vinasse ferti-irrigation.

Bio digestion of vinasse: according to CH4 Concentration and destination Ferti-irrigation Combustion of Vinasse Electricity Fertilizer Effluent: COD (mg Zero 34,563 Zero 98,753 O/L) Electricity Production: MW 57 MW, 36.3 M USD/year 47 MW, 43 M USD/year No No value Ash/Fertilizer No t/year 59,000 NO 146,000 USD/year 12,800,000 29,200,000 No Effluent Lower investment No Effluent Mixed income: electricity and Advantages Lower O&M cost Environmentally friendly fertilizer Bagasse is not required Important volume of Higher investment Lower incomes effluents (bad smell) Disadvantages Supplementary fuel required Higher O&M cost Distilleries > 70,000 m3 Suggested for ethanol/year or a group of smaller facilities Annual Gross It represents income (Millions 49 43 29.2 an expense USD)

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CONCLUSIONS

Ethanol production requires strategies for the final disposal of vinasse in the province of Tucumán. An effort is necessary to promote production and avoid environmental pollution. This causes a significant cost to any distillery.

The study shows two economically viable alternatives:

One in which vinasse could be concentrated, burned in boilers and steam fed to turbine generators to provide 342 GWh (enough to cover 112,000 families’ electricity annual consumption) and ash rich in potassium. Thus, the mixed gross income could reach USD49,000,000/year. However, a high investment is required for the concentration and combustion of vinasse, which suggests that this alternative is suitable for distilleries with a production of more than 70,000 m3 of ethanol/year.

3 The second technology analyzed, the production of biogas from vinasse, could produce 69,000,000 m of CH4/year to produce 282 GWh energy using internal combustion engines (can supply 92,000 families’ annual demand of energy) with a gross income of USD43,000,000/year.

Another possibility would be to use CH4 to process vinasse and generate a fertilizer rich in potassium and humus (besides this option produces a lower income but the absence of effluent has more benefits for the environment and reduces the distilleries’ labor demand).

REFERENCES

Anschau R, Flores Marco N, Carballo S, Hilbert J. 2011. Evaluación del potencial de producción de biocombustibles en Argentina, con criterios de sustentabilidad social, ecológica y económica, y gestión ordenada del territorio. El caso de la caña de azúc ar y el bioetanol. https://inta.gob.ar/documentos/evaluacion-del-potencial-de-produccion-de-biocombustibles-en-argentina-con- criterios-de-sustentabilidad-social-ecologica-y-economica-y-gestion-ordenada-del-territorio.-el-caso-de-la-cana-de-azucar- y-el-bioetanol-1. Centro Azucarero Argentino. 2014. Estadísticas | Centro Azucarero Argentino. http://centroazucarero.com.ar/oldsite/zafras (accessed 19 July 2018). Escartín C, Denaday F, Parodi G, Paracca JI, Bonino MF, Di Leo N, Barasch Y. 2016. Análisis espacial del balance energético derivado de biomasa Metodología WISDOM Provincia de Tucumán. Buenos Aires. España-Gamboa, E, Mijangos-Cortes J, Barahona-Perez L, Dominguez-Maldonado J, Hernández-Zarate G, Alzate-Gaviria L. 2011. Vinasses: characterization and treatments. Waste Management & Research 29: 1235 Tucumán 1250. Fadda G, Morandini M. 2007. El uso agrícola de la vinaza: revisión de antecedentes y caracterización de las condiciones del área cañera tucumana para su aplicación. Estación Experimental Agroindustrial Obispo Colombres, Tucumán. Ferreira ES, Monteiro AO. 1987. Efeitos da aplicação da vinhaça nas propriedades químicas, físicas e biológicas do solo. Boletín Técnico COPERSUCAR 36: 1 Tucumán 7. Hernández Guijarro K, Portocarrero R, Covacevich F. 2018. Efecto de la aplicación de vinaza sobre la dinámica de poblaciones microbianas edáficas. II simposio de residuos agropecuarios y agroindustriales del NOA y cuyo. San Juan, Argentina. Indian Sugar & General Engineering Corporation (ISGEC Heavy Engineering Limited). 2018. http://www.isgec.com/. Lorenzo-Acosta Y, Valdéz Delgado A, Domenech López F, Rojas Sariol L, Sánchez F. 2014. Cálculos técnicos en el diseño de una planta de biogás. Caso de estudio Tratamiento de vinazas de destilerías en reactores UASB. ICIDCA sobre derivados de la caña de azúcar 48(2): 28 Tucumán 34. Morandini M. 2010. Alternativa del manejo de vinaza en la provincia de Tucumán. Aplicación de vinaza en suelos no productivos. Estación Experimental Agroindustrial Obispo Colombres, Tucumán. Morandini M, Quaia E. 2013. Alternativas para el aprovechamiento de la vinaza como subproducto de la actividad sucroalcoholera. Estación Experimental Agroindustrial Obispo Colombres, Tucumán. Ortiz JM. 2018. Producción de energía a partir de vinaza en Tucumán: análisis de las diferentes alternativas. (Master Tesis). Instituto Tecnológico de Buenos Aires, Buenos Aires. Perera JG. 2009. Concentración y combustión de vinazas. Ministerio de Gobierno y Justicia de la Provincia de Tucumán, Secretaría de Estado de Gobierno y Justicia, Subsecretaria de Asuntos Técnicos. Portocarrero R, Correa MA, Vallejo JI, Ullivarri E, Valeiro AH. 2018. Salinidad por aplicación de vinazas de un suelo subtropical cultivado con caña de azúcar. Ciencies Suelo (Argentina) 36(2): 39–47. Valeiro A, Portocarrero R, Ullivarri E, Vallejo J, Famaillá IE. 2017. Los Residuos de la Industria Sucro-Alcoholera Argentina.

Canne à sucre: potentiel de production d’électricité à partir de vinasse issue de l’éthanol

Résumé. Tucumán est le plus grand producteur argentin de bioéthanol de canne à sucre. Le principal effluent du procédé est la vinasse, un liquide avec une DCO et une DBO plusieurs fois supérieures à celles autorisées par les autorités pour être rejetées dans un plan d'eau. Actuellement, la vinasse est irriguée dans des champs de canne à sucre ou utilisée pour le compostage. En 2017, Tucumán a produit près de 300 000 m3 d'éthanol et 3 600 000 m3 de vinasse. Deux modèles théoriques ont été

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proposés pour tirer parti de la vinasse. Le premier utilise de la vinasse concentrée et de la bagasse comme combustible auxiliaire à brûler dans une chaudière. Le second consiste à générer du biogaz à partir de vinasse en utilisant la méthodologie utilisée par la FAO dans l'analyse de la sagesse de 2016 pour Tucumán et à l'ajuster en fonction des critères des industries locales. Les deux modèles calculent l'énergie fournie pour générer de l'électricité, le premier utilisant la chaleur générée par la combustion pour faire fonctionner une turbine et le second utilisant le biogaz dans les moteurs à combustion interne. Le prix pour 1 MWh était celui attribué dans RenovAr 2.0 (promotion nationale de l'Argentine pour l'utilisation de sources d'énergie renouvelables 3 pour produire de l'énergie électrique). L’étude montre que 69 Mm de CH4/an pourraient être produits pour fournir 282 GWh de moteurs à combustion interne avec un revenu brut de 43 000 000 USD/an et que la vinasse pourrait être concentrée pour fournir 342 GWh de turbines afin d’obtenir des cendres riches en potassium, revenu brut mixte de 49 000 000 USD/an. En raison du volume énorme de vinasse produit chaque année à Tucuman et du coût considérable qu'une manipulation appropriée impose aux distilleries, une élimination alternative est requise. Il devrait inclure une option capable de générer un revenu économique. En raison des investissements importants requis pour la concentration et la combustion de la vinasse, cette technologie est recommandée pour les distilleries produisant plus de 70 000 m3 d'éthanol/an, tandis que la production de biogaz est recommandée pour les plus petites.

Mots-clés: Canne à sucre, vinasse, énergie, durabilité, environnement

Energía de la caña de azúcar: Producción potencial de electricidad a partir de vinaza de la industria sucro-alcoholera

Resumen. Tucumán es el mayor productor Argentino de bioetanol de caña de azúcar. El principal efluente del proceso es la Vinaza, un residuo líquido cuya concentración supera cientos de veces el máximo establecido por la autoridad de aplicación provincial. Actualmente la vinaza se aplica sobre los suelos en forma de riego o se realiza compostaje. En 2017 Tucumán produjo casi 300.000 m3 de etanol y aproximadamente 3.600.000 m3 de vinaza. Para aprovechar la vinaza se propuso trabajar sobre dos modelos teóricos. El primero utiliza vinaza concentrada y un suplemento calórico, bagazo, para realizar una combustión directa en la caldera. El segundo modelo consiste en generar biogás con la vinaza considerando el criterio utilizado por la FAO en el Análisis Espacial del Balance Energético Derivado de Biomasa: Metodología Wisdom, Provincia de Tucumán y ajustando el mismo con valores obtenidos en la industria local. Ambos modelos calculan la energía eléctrica potencial que podría obtenerse, el primero utilizando el vapor generado en la caldera para operar una turbina y el segundo el biogás en motores de combustión interna. El precio del MWh considerado fue el adjudicado durante la ronda RENOVAR 2.0 para proyectos similares. Debido al enorme volumen de vinaza a disponer anualmente en Tucumán y al costo que implica un manejo adecuado en las arcas de cualquier destilería se necesita una alternativa diferente. Del estudio realizado surge que podrían producirse 69.000.000 m 3

CH4/año, para proveer 282 GWh a través de motores de combustión interna generando un ingreso bruto de 43.000.000 US$/año o se podría concentrar Vinazas para proveer 342 GWh mediante turbinas y obtener cenizas ricas en Potasio, con un ingreso bruto mixto de 49.000.000 US$/año. - Debido a la elevada inversión necesaria para la concentración y combustión de Vinazas, esta tecnología se sugiere para destilerías que produzcan más de 70.000 m3 etanol/año.

Palabras clave: Caña de azúcar, vinaza, energía, sustentable, medio ambiente

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ANNEX I

Considering a 70% of 60 Bx vinasse and 30% of bagasse 52% moisture: Vinasse = 1,650 kcal/kg * 663,971 t vinasse 60 Bx * 1,000 kg/t = 1,095,552,150,000 kcal. The percentage of bagasse per t of sugarcane may vary depending on the physiological state of the plant and the harvesting style used but generally it is considered to be around 300 kg of bagasse per t of crushed cane. (Valeiro et al. 2017) According to the Argentinian Sugar Cane Center, between 04-2017 and 04-2018, a total of 15,186,549 t sugar cane were milled producing ~ 4,555,964 t bagasse. The bagasse Lower Calorific Value is 1,850 kcal/kg. Bagasse= 4,555,964 t de bagasse*0.3 * 1,850 kcal/kg ~368,503,350,000 kcal Potential kcal/year = Bagasse kcal + Vinasse 60 Bx kcal = 1,464,055,500,000 kcal. 1 MWh = 859,845.2 kcal: 1,464,055,500,000 kcal = 1,702,697MWh Period [hours] = 250 days * 24 hours = 6,000 hours [1,702,697 MWh * 0.20 (electric plant’s efficiency)] / 6,000 hours = 56.75 MW For a project of concentration and combustion of vinasse in Tucumán during RENOVAR 2.0 a price of 106.73 US$/MWh was adjudicated (the price corresponds to energy from combustion of concentrated vinasse). 1,702,697 MWh * 0.2 * 106.73 U$/MWh = 36,345,770.162 US$/ year

ANNEX II

According to tests done in facilities that concentrate and combust vinasse 60 Bx around 2.97 t/h fly ashes are generated after the combustion of around 33.33 t vinasse 60 Bx/hour Fly ashes/year = (663,971 t Vinasse 60 Bx * 2.97 t Fly Ashes/h) / 33.33 t vinasse 60 Bx/hour = 59,159.816 t fly ash/year

The analysis of the fly ash made by GENNEIA to its future plant in Tucumán shows a 42.3% K2O and 9.0% PO4. 3 The commodity price for K2O in USA for May of 2018 was 216 US$/t and for Ca5(PO4) was 103 US$/t for the same country and period (World Bank data). + 3 According to the International Plant Nutrition Institute, 1 t KCl contains ~ 52-53% de K (around 60-63 % K2O) and 1 t Ca5(PO4)

~ 15-20 % phosphate (PO4). Then:

1 t KCl ~ 60% K2O = 216 US$

1 t K2O 42,3% = (216 US$*0.43)/0.6 = 154.8 US$ 3 1 t Ca5(PO4) ~ 15% PO4 = 103 US$

1 t PO4 9.0% = (103 US$ * 0.09) / 0.15 = 61.8 US$ Value of 1 t fly ash = 154.8 US$/t + 61.8 US$/t = 216.6 US$/t Fly ash theoretical annual gross income = 59,159.816 t/year * 216.6 US$/t = 12,814,016.14 US$/year

ANNEX III

Vinasse COD/year = Vinasse m3/year * average COD = 3,589,034 m3 vinasse/year * 98.753 kg/m3 vinasse = 354,427,874.6 kg COD/year The convertible COD is around 70%, Lorenzo-Acosta et al. 2014. According to the local industries, value was considered as 65% by authors’ decision. Convertible COD = kg COD/year * 0.65 = 230,378,118.49 kg COD/year 3 From 1 kg of COD there is 0.5 m biogas with 65% CH4, Morandini & Quaia 2013. In this study this value was adjusted to a 60% by recommendation of Philippe Conil (BIOTEC International). 3 3 3 3 3 CH4 [m ]/year = 230,378,118.49 kg COD/year * 0.5 m biogas/kg COD * 0.60 m CH4/ m Biogas = 69,113,435.547 m CH4/year

Annex IV

3 CH4 Lower Calorific Value: 9,000 kcal/m 1 MWh = 859.845,2 kcal 3 3 69,113,435 m CH4/year * 9,000 kcal / m CH4 = 622,020,924,000 kcal ~ 723,410.3 MWh Period considered 250 days= 6,000 hours The efficiency considered for an Internal Combustion Engine (ICE) = 39% Installed capacity= 723,410.3 MWh / 6000 h * 0.39 = 47.0216 MW 153 US$/MWh were paid in 2018 Tucumán to a similar project with RENOVAR 2.0 (CITRUSVIL citric biogas facility). Annual Energy Income = 723,410 MWh/year * 0.39 * 153 US$/MWh = 43,165,874 US$/year

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ANNEX V

3,589,034 m3 vinasse 11.1 Bx ~ 398,382.774 t dry matter 65% organic matter removal = 398,382.774 t dry matter * 0.35 = 139,443.97 t dry matter 5% moisture = 146.405,67 t bio fertilizer available 200 US$/t bio fertilizer is the price paid for this product in south-east Asia, personal communication with Philippe Conil (BIOTEC International). (Note: this product is not available in Latin America yet so it is a theoretical price based on what is paid for this product in Asia, where there are many of these facilities selling this product). Annual Bio fertilizer Gross Income = 146.405,67 t * 200 US$/t = 29,281,133US$/year

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