Solar pyrolysis and electrical furnace pyrolysis of Luffa cylindrica fibers to obtain adsorbent biochar

• Autor(a) principal: Pedro Henrique Cabral de Souza
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/43883; https://orcid.org/ 0000-0002-2071-9309
• topic: Pirólise; Energia solar; Biomassa; Luffa cylindrica; Biocarvão; Adsorção; Engenharia química; Adsorção; Biomassa; Energia solar; Pirolise

In the past decade, many studies have proven the efficiency of Luffa cylindrica fibers on various wastewater adsorption applications. However, once the contaminants are removed from water by the natural fibers, a new solid waste is generated. A great alternative treatment to diminish the environmental impact of this solid waste is the pyrolysis process. Pyrolysis, the thermal decomposition of organics in the absence of oxygen at high temperatures, has been extensively developed as a promising platform to produce fuels and chemicals from various types of biomass. The main products of this process are biochar, bio-oil, and syngas. While the volatile products are usually linked to energetic purposes, some biochars have been widely studied and successfully applied as adsorbent materials. A major challenge of biomass pyrolysis is the necessity to heat the feedstock to high temperatures, which adds to the economic and environmental costs of the process. To address this matter, an alternative is to perform the heating process using concentrated solar energy. In this work, two solar pyrolizers of different designs were built, one with a parabolic trough collector and the other with a parabolic dish collector. Their building costs were R$ 10.000 and R$ 200, respectively. The thermal transfer calculations for the solar pyrolizer are available as a result of this project. This research project studied the slow pyrolysis of Luffa cylindrica to obtain biochar in electric and solar ensembles. Different terminal temperatures (300, 400, and 500 °C) and heating rates (2, 10, and 20 °C.min-1) were tested under a nitrogen atmosphere in the electric furnace. A solar pyrolysis experiment was performed on the solar dish collector pyrolizer under nitrogen flux for 1 hour at temperatures up to 417 °C. The parabolic trough pyrolizer was not operationalized until the writing of this document due to logistics and technical matters. Obtained biochars were characterized via iodine number, TG/DTG, FTIR, HHV, and SEM. The influence of pyrolysis parameters in biochar yield, composition, surface functional groups, morphology, and high heating value was accessed and discussed in this work. All produced biochars and a commercial activated biochar were submitted to iodine adsorption tests to evaluate the influence of process parameters on adsorption performance. The goals set for this work were accomplished since the proposed solar pyrolizers were built, Luffa cylindrica slow pyrolysis was studied with details yet unseen on the literature, and biochars with good adsorptive properties were obtained.