Comprehensive assessment of sugarcane straw: implications for biomass and bioenergy production

Abstract

Sugarcane straw, consisting of green tops and dry leaves, can be maintained on fields to improve soil quality, or harvested for bioenergy production. The optimum option between these two uses is still uncertain and requires further study. This study, conducted across three crop cycles, provides an assessment of the moisture, nutrients, ash, extractives, cellulose, hemicelluloses, and lignin contents of four sugarcane varieties across seven regions of south‐central Brazil. Suitability of the straw fractions for nutrient recycling, bioelectricity, and second‐generation ethanol production were also evaluated. Results showed that the sugarcane straw yield (dry mass) was 14.0 Mg ha−1, and the ratio of dry straw/fresh stalk was 12%. The composition of green tops and dry leaves differed consistently across varieties, sites, and crop cycles. Dry leaves represented 60% of the straw, but green tops contained about 70% of the total N, P, and K content. Therefore, green tops recycled up to four times more nutrients than dry leaves. Green tops also had six times higher moisture and greater chlorine content which decreased the mill process efficiency. In turn, dry leaves had higher lignin, cellulose, and hemicelluloses content, greater heating value (higher: 17.3 MJ kg−1; lower: 15.6 MJ kg−1) and tended to be a better second‐generation ethanol production feedstock. Overall, the results show that it is preferable to use dry leaves for bioenergy production while leaving green tops on the field for nutrient recycling. This study pointed out that more efficient methods for separating these fractions in the field need to be developed. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd

Lignocellulosic biomass from agro‐industrial residues in South America: current developments and perspectives

“…However, other crops are also prominent, such as wheat, cassava, rice, banana, and oil palm. Processing these crops generates large amounts of solid residues, including in‐field or agricultural residues (straw, leaves, and foliage) and agro‐industrial processing residues (bagasse, bunches, and shells) with diverse composition and volume (Table ) …”

Biomass Production and Nutrient Removal of Energy Cane Genotypes in Northeastern Brazil

“…Thus, it is recommended that plant materials have N, Cl, and S in amounts <0, 2, and 3 g kg −1 , respectively, during the combustion process (Surendra et al, 2018). It is important to highlight that energy cane harvesting removes total aboveground biomass (stalks, tops, and dry leaves) and that the tops contain high nutrient concentrations (Menandro et al, 2017). Therefore, knowledge and understanding of nutrients required for energy cane crops is crucial for the development of a sustainable and renewable feedstock for bioenergy production.…”

“…Nutrient concentration in energy cane tops (Table 5) and dry leaves (Table 6) was higher than in stalks and tops, and dry leaf removal from the field may not only diminish the quality of the combustion process (Shahandeh et al, 2011;Tröger et al, 2013;Surendra et al, 2018) but also augment removal of nutrients from the production system (Carvalho et al, 2017b;Bordonal et al, 2018). For sugarcane, recent studies have indicated that part of the sugarcane straw (mainly tops) should be maintained on the field to protect the soil, improve nutrient recycling, and increase biomass yield (Menandro et al, 2017;Bordonal et al, 2018). For sugarcane, recent studies have indicated that part of the sugarcane straw (mainly tops) should be maintained on the field to protect the soil, improve nutrient recycling, and increase biomass yield (Menandro et al, 2017;Bordonal et al, 2018).…”

“…Additionally, the total removal of biomass from the field can increase soil erosion losses (Martins Filho et al, 2009) and consequently reduce the environmental benefits of the energy cane as raw material for bioenergy production. For sugarcane, recent studies have indicated that part of the sugarcane straw (mainly tops) should be maintained on the field to protect the soil, improve nutrient recycling, and increase biomass yield (Menandro et al, 2017;Bordonal et al, 2018).…”

Thermodynamic and Environmental Analysis of Scaling up Cogeneration Units Driven by Sugarcane Biomass to Enhance Power Exports

“…An expressive trend of expansion in this field is expected in the next few years. This is because: (i) Brazil still falls short of fully exploring its energy potential in sugarcane biomass [1,4,5]; (ii) the installed capacity for cogeneration from biomass is 143 GW, representing 9.3% of the domestic energy supply in 2014, and the national commitment is to increase this contribution to 23% by 2030 [6]; (iii) the country has signed international agreements aimed at sustainable development and positive aspects of cogeneration through biomass, but their surveys are narrowed to the use of bagasse as the only energy source.…”