Oxygen updraft gasification of euro cotton banknotes waste for hydrogen-rich syngas production

Abstract

Euro cotton banknote waste (BW) is one of the challenges that the EU region has recently sought vigorously to integrate into the circular economy and to encourage research and investment in its valorisation in order to preserve this sector and reduce its environmental risks. Within this framework, this research aims to study the possibility of treating BW using gasification process and converting it into hydrogen (H₂)-rich syngas. Gasification experiments were performed on euro banknote-based cotton waste that underwent pre-pelletizing treatment to produce uniform BW granules. The conversion process was carried out using a continuous updraft gasifier system with a capacity up to 1 kg/h in oxygen agent. To optimize the process and obtain ideal conditions that can release the maximum amount of H₂ into the synthesized gas, the experiments were conducted at different temperatures (700, 800, 900 °C) and air-fuel equivalence ratios (ER: 0.19, 0.24, 0.29). The syngas, tar, and soot gasification products were characterized using Gas chromatography, Scanning electron microscope (SEM), and Fourier-transform infrared spectroscopy (FTIR). The results show that at 700 °C (ER = 0.24), the maximum syngas production rate (1.16 kg/h) with HHV 9.1 MJ/kg can be obtained together with production of 0.05 kg/h (tar) and 0.79 kg/h (soot). Meanwhile, the highest H₂ content (up to 19 %) was obtained at 900 °C (ER = 0.19) with less tar (0.01 kg/h) and soot (0.49 kg/h). Accordingly, BW treatment using the gasification process is a promising technology for its disposal, especially at a high temperature (900 °C) to convert it into H₂-rich syngas with smaller quantity of tar and soot components.