Avaliação bioenergética de sorgos biomassa, sacarino e forrageiro
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Data
2016-07-29
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Universidade Federal de Viçosa
Resumo
Visando atender à crescente demanda por bioenergia (bioeletricidade e bioetanol), o setor su- croenergético busca alternativas para ampliar a produção de biomassa por unidade de área. Nesta perspectiva o sorgo [Sorghum bicolor (L.) Moench] é visto como matéria-prima promis- sora, pois trata-se de uma planta C4, de ciclo curto, com grande potencial de produção de bio- massa por unidade de área. Existem diversos tipos agronômicos com elevada produtividade de matéria seca por unidade de área e tempo, como o sorgo biomassa, o sacarino e o forrageiro. Entretanto, acredita-se que o real potencial de uso desta cultura ainda não tenha sido explorado adequadamente no setor bioenergético, devido à falta de conhecimento das características des- tes materiais. Deste modo, objetivou-se com este trabalho realizar uma caracterização do po- tencial produtivo e bioenergético de três grupos agronômicos de sorgo (sorgo biomassa, sorgo sacarino e sorgo forrageiro) em duas épocas de corte. Para isso, realizou-se um experimento inédito, discutido neste trabalho em dois capítulos. Capítulo 1: As cultivares de sorgo foram semeados no campo, sendo avaliados em duas safras consecutivas (safra principal e rebrota). Ao final do ciclo de cada variedade foram realizadas avaliações agronômicas (duração do ciclo, altura de plantas, produção de massa fresca e massa fresca /ha e participação das partes na biomassa total das plantas), estrutural (composição lignocelulósica) e bioenergética (poder ca- lorifico superior) da planta de sorgo, afim de caracterizar a produção de energia potencial (GJ) por unidade de área de cada cultivar e estudar o melhor uso destes matérias no setor bioenergé- tico. Verificou-se que o potencial de produção de massa fresca total é maior na safra para todas as cultivares, e as cultivares BD 7607 e BRS 716 (sorgo biomassa) apresentaram as maiores produções de biomassa, 110 e 108 t/ha respectivamente. A produtividade das cultivares na re- brota foi pouco significativa devido às condições climáticas desfavoráveis. Foi verificado tam- bém que o poder calorifico superior foi maior nas folhas para todas as cultivares em relação aos outros componentes das plantas e que as cultivares que apresentaram maior produção de massa seca/ha, pertencentes ao grupo do sorgo biomassa (BD 7607 e BRS 716), consequentemente também apresentaram maior produção de energia/ha. No segundo capítulo, foi avaliado a pro- dução quantitativa e qualitativa dos açúcares produzidos no colmo apenas das cultivares per- tencentes ao grupo do sorgo sacarino, em duas épocas de corte (safra principal e rebrota). Para isto foi realizada a extração do caldo e posteriormente foi determinado o teor de açúcares totais (sacarose, glicose e frutose) em cromatografia líquida de alta eficiência (HPLC). Foi verificado que a quantidade de açúcares (açúcares totais) produzidos não varia em função dos ciclos, po- rém a taxa de extração diminui na rebrota o que pode resultar em menores rendimentos indus- triais por tonelada de matéria-prima processada. Também, observou-se que a qualidade dos açúcares varia de acordo com a cultivar e estádio de desenvolvimento da planta. Conclui-se que a quantidade de energia produzida por cada tipo de sorgo é diretamente influenciada pelo seu desempenho agronômico e pela composição estrutural. A composição quantitativa e qualitativa dos açúcares presentes no caldo das cultivares de sorgo sacarino variam em função da época de corte e da cultivar.
To meet the growing demand for bio-energy (bioelectricity and bioethanol), the sugarcane in- dustry seeks alternatives to expand production of biomass per unit area. In this perspective sorghum [Sorghum bicolor (L.) Moench] is seen as a promising raw material, because it is a C4 plant, short cycle, with great potential for biomass production per unit area. There are several types with high agronomic yield of dry matter per unit area and time such as sorghum biomass, saccharine and forage. However, it is believed that the actual potential use of this culture has not yet been properly exploited in bioenergy industry, due to lack of knowledge of the charac- teristics of these materials. Thus, the aim of this study was to perform a characterization of productive and bioenergetic potential of three agronomic groups of sorghum (sorghum biomass sorghum and forage sorghum) at two cutting times. For this, there was an unprecedented expe- riment discussed in this paper in two chapters. Chapter 1: The sorghum cultivars were planted in the field, being evaluated in two consecutive crops (main crop and regrowth). At the end of the cycle of each variety were carried out agronomic evaluations (cycle length, plant height, fresh pasta production and fresh weight / ha and participation of the parties in the total biomass of plants), structural (lignocellulosic composition) and bioenergetics (calorific top) of the sorghum plant, in order to characterize the potential energy (GJ) per unit area of each cultivar and study the best use of these materials in the bioenergy sector. It was found that the total fresh mass production potential is higher in yield for all cultivars, and cultivars BD 7607 and BRS 716 (sorghum biomass) had the highest biomass production, 110 and 108 t/ha respectively. The grain yields in regrowth was negligible due to unfavorable weather conditions. It was also found that the higher calorific value was higher in the leaves for all cultivars in relation to other com- ponents of plants and cultivars that showed higher dry matter yield/ha, belonging to the sorghum biomass group (BD 7607 and BRS 716) consequently also showed higher energy /ha. In the second chapter, it was assessed the quantitative and qualitative production of sugar pro- duced in the stem only from cultivars belonging to the sorghum group in two harvest periods (main crop and regrowth). To this was done extracting the broth and was subsequently given the total sugar content (sucrose, glucose and fructose) in high-performance liquid chromatogra- phy (HPLC). It was found that the amount of sugar (total sugars) produced does not vary as a function of cycles, but the extraction rate decreases the regrowth which may result in lower yields industrial per ton of feedstock processed. Also, it was observed that the quality of sugars varies with the cultivar and plant development stage. It follows that the amount of energy pro- duced by each type of sorghum is directly influenced by agronomic performance and structural composition. The quantitative and qualitative composition of sugars in the juice of sweet sorghum cultivars vary depending on cutting time and cultivar.
To meet the growing demand for bio-energy (bioelectricity and bioethanol), the sugarcane in- dustry seeks alternatives to expand production of biomass per unit area. In this perspective sorghum [Sorghum bicolor (L.) Moench] is seen as a promising raw material, because it is a C4 plant, short cycle, with great potential for biomass production per unit area. There are several types with high agronomic yield of dry matter per unit area and time such as sorghum biomass, saccharine and forage. However, it is believed that the actual potential use of this culture has not yet been properly exploited in bioenergy industry, due to lack of knowledge of the charac- teristics of these materials. Thus, the aim of this study was to perform a characterization of productive and bioenergetic potential of three agronomic groups of sorghum (sorghum biomass sorghum and forage sorghum) at two cutting times. For this, there was an unprecedented expe- riment discussed in this paper in two chapters. Chapter 1: The sorghum cultivars were planted in the field, being evaluated in two consecutive crops (main crop and regrowth). At the end of the cycle of each variety were carried out agronomic evaluations (cycle length, plant height, fresh pasta production and fresh weight / ha and participation of the parties in the total biomass of plants), structural (lignocellulosic composition) and bioenergetics (calorific top) of the sorghum plant, in order to characterize the potential energy (GJ) per unit area of each cultivar and study the best use of these materials in the bioenergy sector. It was found that the total fresh mass production potential is higher in yield for all cultivars, and cultivars BD 7607 and BRS 716 (sorghum biomass) had the highest biomass production, 110 and 108 t/ha respectively. The grain yields in regrowth was negligible due to unfavorable weather conditions. It was also found that the higher calorific value was higher in the leaves for all cultivars in relation to other com- ponents of plants and cultivars that showed higher dry matter yield/ha, belonging to the sorghum biomass group (BD 7607 and BRS 716) consequently also showed higher energy /ha. In the second chapter, it was assessed the quantitative and qualitative production of sugar pro- duced in the stem only from cultivars belonging to the sorghum group in two harvest periods (main crop and regrowth). To this was done extracting the broth and was subsequently given the total sugar content (sucrose, glucose and fructose) in high-performance liquid chromatogra- phy (HPLC). It was found that the amount of sugar (total sugars) produced does not vary as a function of cycles, but the extraction rate decreases the regrowth which may result in lower yields industrial per ton of feedstock processed. Also, it was observed that the quality of sugars varies with the cultivar and plant development stage. It follows that the amount of energy pro- duced by each type of sorghum is directly influenced by agronomic performance and structural composition. The quantitative and qualitative composition of sugars in the juice of sweet sorghum cultivars vary depending on cutting time and cultivar.
Descrição
Palavras-chave
Sorghum bicolor, Sorgo - Produtividade, Bioenergia
Citação
BATISTA, Vanessa Aparecida Pereira. Avaliação bioenergética de sorgos biomassa, sacarino e forrageiro. 2016. 68f. Dissertação (Mestrado em Fitotecnia) - Universidade Federal de Viçosa, Viçosa. 2016.