Insights into the role of CaO addition on the products distribution and sulfur transformation during simulated solar-powered pyrolysis of waste tires. (15th April 2022)

• Record Type: Journal Article
• Authors: Cao, Chengyang; Ren, Yang; Wang, Hao; Hu, Hongyun; Yi, Baojun; Li, Xian; Wang, Linling; Yao, Hong
• Is Part Of: Fuel. Volume 314(2022)
• Publication Date: 2022-04-15
• Subjects: Waste tires -- Pyrolysis -- Product distribution -- Sulfur transformation -- CaO; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2021.122795
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: Effects of CaO addition on the solar-powered pyrolysis of waste tires were studied. CaO addition act as thermal conductor, absorbent and catalyst during pyrolysis. Competition and interaction reaction by CaO addition facilitated SO2 emission. The average sulfur fixation rate reached over 75% with 10 wt% CaO addition. A simplified reaction map of sulfur transformation during pyrolysis was proposed. Abstract: Solar-powered pyrolysis of waste tires has been extensively studied because it can rapidly convert waste tires into valuable gas products using sustainable energy. However, the emitted sulfurous pollutants during this fast pyrolysis process would significantly reduce the economic feasibility of disposal waste tires. In order to investigate and regulate the sulfur transformation behavior, a large-load thermogravimetric analyzer and an optical rapid thermal processor were adopted to characterize and simulate the solar-powered fast pyrolysis behavior. The sulfur fixation effect of CaO was also evaluated in this study. Results showed that CaO addition could increase the emission of H2 and CO by promoting the cracking of organic compounds in tar. In comparison, it could decrease the CO2 emission by adsorption or transformation. Also, an excellent sulfur fixation rate in char was achieved with 10 wt% CaO addition, but accompanied by increasing emission tendency of SO2, especially at 650 °C-6000 °C/min. It was attributed to the competition reaction between H2 S and SO2 in the gas phase and interaction between CaS and CaSO4 in the condensed phase. Our findings could be beneficial to develop an in-situ sulfur removal method during the pyrolysis of waste tires in the industry.