Produção de biocarvão a partir de biomassa de babaçu visando a aplicação agrícola

Abstract

The babassu production chain is one of the most representative of vegetal extractivism in Brazil, but results in high generation of waste with potential for utilization. The present study aims to produce biochar from babassu biomass through pyrolysis process aiming at agricultural application. The precursor material was composed of babassu epicarp, mesocarp and endocarp and was characterized in clean and raw form. The production of biochar was carried out with the raw biomass in four operating conditions, and the obtained biochars were submitted to prior characterization tests. The production of biochar on a larger scale was carried out in a fixed bed reactor at a temperature of 350ºC, rate of 10ºC/min, residence time of 20 minutes and N2 flow of 1mL/min. The agricultural application consisted in subjecting L. sativa seeds to two treatments containing biochar (Bio25% and Bio50%), these treatments were compared to a control treatment (Bio0%), whose growth was evaluated for 28 days. The characterization of the biomasses resulted in 0.98 wt% of particles adhered to the biomass, higher fraction of particles with an average diameter of 3.57 mm for both biomasses, moisture content of 16.66 and 17.43 wt%, ash content of 1.76 and 2.04 wt%, volatile matter of 82.27 and 82.48 wt%, fixed carbon of 15.65 and 16.38 wt%, pH of 6.29 and 6.47, electrical conductivity of 445.0µS/cm and 436.6µS/cm, real specific mass of 1.3950 g/cm3 and 1.3989 g/cm3, surface area of 0.3422 m2/g and 0.5431 m2/g and higher calorific value of 18.326 MJ/kg and 18.674 MJ/kg for the clean and raw biomass, respectively. The elements K, Si, Ca, Fe, S, P, Cu were identified in the biomasses, besides the element Al for the crude biomass. The babassu biochar produced on a larger scale showed yield of 33.26 wt%, higher particle fraction of 3.57mm, 4.71 wt% ash, 29.20 wt% volatile matter, 66.09 wt% fixed carbon, pH of 8.98, electrical conductivity of 138.1µS/cm, real specific mass of 1.3804 g/cm3, higher calorific value of 27.94 MJ/kg, elements K, Si, Ca, Fe, Mg, S, P, Cu and Rb and CEC of 34.77mmol/kg. In agricultural application it was observed that the treatments with biochar resulted in seedlings with greater height and more vivid coloration, indicating that babassu biochar may have potential to be used to improve soil characteristics for agricultural application.