RESUMEN
Butia capitata endocarp (BCE) is a biomass residue with the potential to produce a wide variety of bio-products. The processing of BCE in a sequential process of subcritical water hydrolysis (SWH) and hydrothermal liquefaction (HTL) was investigated to obtain fermentable sugars, platform chemicals, bio-oil, and biochar. The SWH was evaluated at 230 and 260 °C and solvent: feed mass ratios (R) of 10 and 20 for the production of fermentable sugars and platform chemicals. The solid residue from SWH was sequentially submitted to the HTL at 330 and 360 °C for bio-oil and biochar production. The results were analyzed by comparing the sequential (SWH/HTL) and individual (HTL only) processes. The highest yields of fermentable sugars (5.26 g/ 100 g BCE) were obtained for SWH at 260 °C and R-20 with higher contents of xylose (2.64 g/100 g BCE) and cellobiose (1.75 g/100 g BCE). The highest yields of platform chemicals (2.44 g/100 g BCE) were obtained for SWH at 260 °C and R-10 with higher contents of acetic acid (1.78 g/100 g BCE) and furfural (0.54 g/100 g BCE). The highest yield of bio-oil (25.30 g/100 g BCE) occurred in HTL individual process at 360 °C and R-20. Sequential process SWH/HTL showed a decrease in bio-oil yield but maintained a similar biochar yield compared to HTL, in addition to the production of fermentable sugars and platform chemicals.
RESUMEN
A presente análise tem a finalidade de comparar o desempenho entre unidades e atividades produtivas, interligando os parâmetros energéticos aos econômicos. O objetivo deste trabalho foi analisar a relação entre a energia produzida e consumida durante o processo de produção das principais culturas de cereais do Estado do Rio Grande do Sul, a saber, trigo, arroz e soja, em contraposição aos resultados econômicos das respectivas atividades. A pesquisa foi do tipo exploratória, a partir de estudos de multicaso, com uso de pesquisa bibliográfica, análises de laboratório e entrevistas. Para determinar os resultados de análises energéticas, foram realizados os balanços energéticos e as eficiências culturais e energéticas das culturas. Para determinar os resultados econômicos das atividades estudadas, foi utilizada a Teoria do Valor Agregado. Os resultados demonstram que a atividade da soja, em sistema de plantio direto com rotação de culturas, alcançou a maior eficiência energética, entre 25,58MJ ha-1 a 38,39MJ ha-1, sendo que a relação de menor eficiência foi a cultura do trigo, com 3,13MJ ha-1. Em relação ao desempenho econômico das culturas, a soja igualmente mostrou a melhor eficiência econômica igual a 2,47 e a do trigo foi de 1,14 a menor. Cabe destacar os significativos resultados econômicos obtidos pela cultura do arroz, expressos pelo alto valor agregado, obtido por unidade de área (VAL/ha de R$ 3.802,00) em função de sua alta produtividade física. Apesar dos indicadores energéticos serem positivos, houve significativos gastos com fertilizantes, combustíveis e agrotóxicos em todas as propriedades estudadas. Dessa forma, reforça-se a importância do debate sobre a sustentabilidade socioambiental dos sistemas estudados, principalmente quando analisados sob a ótica dos gastos energéticos de bens não-renováveis e da problemática social atribuída à mão-de-obra.
The energy analysis aims to compare the performance between productive units and activities, searching an approach to link the energy with the economic. Objectives is the analysis of the energy produced and consumed during the production process of major crops in the state of Rio Grande do Sul, namely, rice, soybeans and wheat, opposed to the economic results of such activities. The research was exploratory and based on multi-case studies with the use of literature review, laboratory analysis and interviews. To determine the results of energy analyzes were performed energy audits and energy efficiencies and cultural crops, while for the economic results we used the theory of Earned Value. The results demonstrate that the activity of soybean in no-tillage system with crop rotation achieved the highest energy efficiency between 25.58MJ ha-1 and 38.39MJ ha-1, whereas wheat culture showed the lowest efficiency with 3.13MJ ha-1. Regarding the economic performance of crops, soybeans showed the highest economic efficiency 2.47 and wheat the lowest 1.14. It is worth mentioning the significant economic results achieved by the rice crop, expressed by the high added-value obtained per unit area (VAL/ha R$ 3,802.00) due to its high physical productivity. In spite of having positive energy indicators, significant expenses on fertilizer, fuel and pesticides were observed in all properties studied. Thus, we reinforce the importance of the debate on social and environmental sustainability of the systems studied, especially when analyzed from the perspective of energy expenses of non-renewable resources and social problems attributed to workforce.