Co-gasification characteristics of waste tire and pine bark mixtures in CO2 atmosphere

Abstract

Co-gasification of waste tire and pine bark in CO2 atmosphere is reported at different blend fractions of waste tire (WT) and pine bark (PB) in the range of WT:PB = 0:1, 1:0, 1:1, 1:3, and 3:1 with a focus on syngas production. The results are reported along with the thermal decomposition behavior of the blends investigated using thermogravimetric analyzer (TGA) in Ar atmosphere. Characteristics of syngas from the gasification of blends were conducted using a fixed-bed reactor in CO2 atmosphere at 800 and 900 °C. Gasification behavior was examined with focus on evolved flow rate of H2, CO, total hydrocarbons (CmHn), and total syngas yield at the two temperatures for different blend ratios. CO2 consumption under the gasification conditions was evaluated. Gas yield efficiency and energy recovered in gasification were also calculated and compared. Synergistic effects in the syngas yield and the role of waste tire and pine bark were analyzed by a direct comparison of the results on experimental yields from WT-PB blends as compared to the correspondingly calculated aggregate results from the gasification of separate feedstock components at 800 °C and 900 °C. Results showed that increase in pine bark ratio increased peak flow-rate of H2, CO, total syngas, but decreased peak flow-rate of CmHn at the two temperatures. The syngas yield of gases at 900 °C were higher than that at 800 °C for a given blend ratio. The peak value of temporal CO2 consumption coincided with the peaks of CO yield for all the feedstocks except for pure waste tire at 800 °C and 900 °C. Gas yield efficiency of gasification at 800 °C reduced using blends, while no obvious influence was found at 900 °C. Increase in pine bark decreased the energy output both at 800 °C and 900 °C. These results provide an insight into energy recovery and waste treatment potential for both waste tire and forestry waste as well as CO2 utilization in the thermochemical conversion.