ABSTRACT:
This study aimed to evaluate the quality of forest biomass energy, coming from the Caatinga, for different storage times in the field. The study was conducted in southern Piauí, between January and February (rainy season). Samples were collected containing branches and trunks of various species, and samples of branches and trunks separately in 5 sample units of 20x20m. Samples were evaluated in the general state freshly harvested and samples of branches and logs after 15 and 30 days of storage in piles in the field. The analyzes carried out were: moisture content on wet basis, ash content and calorific value. Moisture content of freshly harvested biomass ranged from 39% with two days after cutting to 79% in biomass cut and left distributed in the field for 10 days. After storage in piles for 15 days, branches showed moisture content of 18% and the logs 21%, and net calorific value of 3432kcal kg-1 and 3274kcal kg-1, respectively. After 30 days, moisture content for branches was 13% and the logs 21%, and net calorific value of 3672kcal kg-1 and 3240kcal kg-1, respectively. Ash content of the biomass was low. Cutting trees in the rainy season, with maintenance of biomass in the field for 10 days, resulted in an increment of moisture content. Branches had the best behaviour during the storage. Fifteen days of storage are sufficient for the caatinga biomass to achieve high-quality energy.
Key words:
firewood; Piauí; calorific value; moisture content
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