Purification of recovered carbon black from waste tires pyrolysis

• Autor(a) principal: Silva, Clara Margarida Carvalho
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/32471
• topic: Characterization of carbon black; Pilot-scale tests; Purification of carbon black; Recovered Carbon Black (rCB); Thermal treatment

The increasing concern with environmental protection has led companies to continuously adopt more sustainable practices during their operation. The mission of BB&G-AWES company is the thermal conversion of residues, in particular end-of-life tires, in the circular economy scope. The patented process allows the production of three products - fuel, syngas and recovered carbon black (rCB). Besides the residues’ valorisation, the process enables the reduction of the consumption of fossil fuels for the production of carbon black (CB). This dissertation is the result of a partnership between BB&G-AWES and the University of Aveiro, aiming the following main goals: i) implementation of characterization methods for the rCB, defined by the characterization standards for CB; ii) study the influence of the operating conditions of BB&G-AWES pilot unit on the produced rCB quality; iii) adaptation of the unit and definition of the treatment/purification conditions of low-quality rCB. The rCB samples produced in the company for different conditions of temperature (500 to 600 ºC) and residence times (11 to 14 min) were characterized regarding the particle size distribution, morphology, chemical composition, volatile content, ash content and thermal behaviour. The results allowed the validation of the analytical procedures and to conclude that the rCB produced has high quality, especially regarding the organic volatile content with toluene transmission values above 98 % for the samples produced at 525, 550 and 600 ºC and 95 % for the 500 ºC sample. The pilot unit was adapted to thermally purify the rCB samples with high levels of organic contamination (ca. 18 wt.%). The method was studied in a temperature range from 450 to 600 ºC, with residence times between 11 and 15 min. For each one of these conditions, a significative reduction of the organic volatiles content was verified, reaching values inferior to 1 wt.% for the treatment assays at 600 ºC and around 2 wt.% for the 450 and 550 ºC assays. The efficiency of the thermal treatment was also confirmed by the toluene transmission values that went from 0.01 % (non-treated rCB) to being superior to 98.5 % for the treatments at 600 ºC. Overall, the obtained results allow the recognition of the operating temperature as the parameter with most impact on the quality of the purified rCB.