Lignocellulosic Biomass Residues Identification and Selection in Five Countries of Latin America, As a Feedstock for Second Generation Ethanol Production

Lignocellulosic biomass residues identification and selection in five countries of Latin America, as a feedstock for second generation ethanol production
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Emilio Ruz

Executive Secretary PROCISUR

www.procisur.org.uy

This presentation is part of a recently completed project: “New feedstock and innovative transformation process for a more sustainable development and production of lignocellulosic ethanol” (BABETHANOL)
www.babethanol.com
, a collaborative project for specific international cooperation actions SICA, Grant agreement N° 227498 of the 7th framework program of the European Commission.

The main objective of the BABETHANOL project was to develop new solutions for a more sustainable approach of second generation ethanol production, based on a “moderate, environmental-friendly and integrated” pre-treatment process of lignocellulosic biomasses. This pre-treatment of the biomass has been the main barrier to overcome in second generation ethanol. The new process, called CES (Combined Extrusion-Saccharification), is an alternative to the current pre-treatments of the state-of-the-art, requiring much energy, water, chemical products, detoxification and waste treatments. It has been developed and tested up to TRL 5 (Technology Readiness Level) from laboratory to pilot scales with seven selected biomasses covering a large range of diversified feedstock.

In parallel to the process development, a feedstock catalogue of diversified crop and agroindustrial wastes was built along the project from investigations run in Argentina, Brazil, Chile, France, Germany, Italy, Paraguay, Spain, United Kingdom and Uruguay, by one partner in each continent. The main idea was to identify concentrated amounts of indigenous lignocellulosic wastes currently available at local/regional scales for the prompt deployment of small, medium or large size second generation ethanol plants near the biomass production sites once the new process will be ready for industrialization.

We are hereby presenting the results of IICA-PROCISUR research
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in five countries of South America: Argentina, Brazil, Chile, Paraguay and Uruguay.

The final selection of the feedstock was performed after investigating: 1) the biomass availability taking into account current situation with competition for other uses (soil

cover, animal feeding and/or bedding and energy); 2) the chemical compositions of the preselected biomasses; and 3) the concentration of feedstock at local level (within 100 km radius) to supply at least 30,000 t dry matter/year.

Argentina

Although Argentina is one of the largest producers and exporters of agricultural goods generating large amounts of residues, originated by the agricultural and agro-industrial sector, only a few were selected according to the required characteristics, availability and geographical dispersion. Precautious measures were taken into account for agricultural production systems since there are most under no tillage, and therefore, cover and organic material and nutrients must be reserved in the soils in order to avoid a rapid deterioration. In the case of agro-industrial products, competitiveness with other uses, physical and chemical characteristics and availability in volume and dispersion during the year were the main concerns. The biomasses found as the most suitable feedstock for the production of ethanol with the CES process were: corn cobs, vineyard pruning, sugar cane field residues (tops and leaves) and bagasse, and eucalyptus field and industrial residues. Less important was wheat straw because of its relatively low amount of cellulose.

For corn cob, three departments in the province of Cordoba: Marco Juarez, Unión and Río Cuarto, producing each of them over 100,000 t/year corn cob, were highlighted since they could match with minimum volume availability requirements. For vineyard pruning, the provinces with higher volumes of residues were San Juan and Mendoza. Two supply basins in a 25 km radius were detected at San Martin (100,000 t/year) and Maipu (35,000 t/year) departments in the province of Mendoza. For sugar cane field residues, two supply areas for ethanol plants were identified: the north, with 260,000 t/year and the south, with 220,000 t/year, both in a 20 km radius. For sugar cane bagasse, a main supply basin was identified around Concepción sugar cane mill in the province of Tucuman with 100,000 t/year bagasse available in 5 km radius and almost 200,000 t/year in a 30 km radius. Eucalyptus residues are concentrated in the provinces of Corrientes and Entre Rios. Forest residues amount to 170,000 and 230,000 t/year respectively.

Brazil

With regards to chemical composition and availability, sugarcane residues (bagasse and trash) are the only feedstock convenient and currently available for ethanol production. The residues from the production chains of soybeans, maize, banana, wheat, coffee and pineapple, with suitable chemical composition which are not available now-a-days under current uses, may offer a second list of additional feedstock that have the potential of being used in the future if the production of second generation ethanol picks up. In Brazil, the most logical alternative would be to locate a production unit of second generation ethanol, in an already existing or close to a processing unit of sugarcane. In this respect, there is a high concentration of industrial plants in the following states: Alagoas and Pernambuco (Northeast region), Goiás and Mato Grosso do Sul (Centre-West region), Sao Paulo and Minas Gerais (Southeast region) and Paraná (South region).

The minimum amount of residues required for the operation of a 30,000 tons of dry material per year processing capacity plant is guaranteed in the following situations: if the trash is not used (or if it is unavailable), in industrial plants with processing capacity of over 2 M tons of sugarcane per season and with the use of trash, in industrial plants with processing capacity over 0.5 and 2.0 million tons of sugarcane per season. There are several industrial plants of sugarcane in Brazil with processing capacities in these ranges, located in the CO/SE/S and N/NE regions. Moreover, there are areas with high concentration of industries in these regions.

Chile

From all the materials originally considered and assessed wheat straw and corn stover field residues as well as vineyard and orchard pruning residues were selected as potential feedstock suitable for the production of ethanol under the CES process. Best residues supplying basins were identified in the following areas: wheat straw in the Araucania region with over 500,000 t/year; corn stover in the O’Higgins region with over 500,000 t/year; apple and vineyard pruning residues in five regions (Coquimbo, Valparaíso, Metropolitana, O’Higgins and Maule) with amounts varying from 150,000 to 280,000 t/year in each region.

Paraguay

In general, the climate of Paraguay characterized for high temperatures and humidity all year round, influences the dynamic of the degradation of organic matter left in the

fields, accelerating the decomposition process which requires that most of the crop residues should not be removed from the soil for sustainability reasons. For this reason, field residues from major cultures like sugar cane, soya, wheat and corn are not collected and therefore not available for other uses. Sugarcane bagasse is the only residue produced in large quantity which is available and suitable for ethanol production and the CES process. Although it is already used to produce energy, there are seasons when there would be sufficient surplus to supply 2nd generation ethanol plants. The province of Guaira appears as the best location for the supply of bagasse with 54,000 t/year in a 30 km radius.

Uruguay

Among a wide variety of residues of the Uruguayan agro-industry, the ones that apparently were most suitable as feedstock for the CES process were wheat, rice and forestry field residues, as well as rice and forestry industrial residues. During the chemical screening both rice residues presented a chemical composition that was not suitable for the production of ethanol with the CES process: for straw the cellulose was too low, for the hull the lignin was too high and for both of them the mineral content was too high. Although wheat straw had better chemical composition, cellulose content was slightly under the limit. So wheat straw was considered as a second choice feedstock. Among the forestry residues, Eucalyptus presented very high cellulose content and good content for all the other compounds, except for forestry industrial residues with lignin slightly above the limit. Several country departments produce sufficient biomass to supply ethanol production plant, especially Rivera, Paysandú, Río Negro and Rocha with amount available ranging from 90,000 to 140,000 t/year within a 30 km radius or less in some zones. So Eucalyptus forestry residues are considered first choice feedstock for the production of ethanol and for the CES process in Uruguay.