Nitrogen-containing gaseous products of chrome-tanned leather shavings during pyrolysis and combustion.

Chrome-tanned leather shavings (CTLS) are a type of solid waste generated from the leather industry. In this study, the pyrolysis and combustion of CTLS in nitrogen and air, respectively, were investigated using a thermogravimetric analyser coupled with Fourier transform infrared spectroscopy (TG-FTIR). A heating rate of 20 °C min-1 was applied, with a final temperature of 1000 °C. The pyrolysis process can be subdivided into three stages (drying the sample, fast thermal decomposition and a further cracking process), whereas the combustion process can be subdivided into four temperature stages. The TG/DTG curves for pyrolysis and combustion were similar at lower temperatures. Multiple peaks were observed for combustion in the temperature range of 250 °C to 580 °C. The emissions of CO2, NH3, HCN, HNCO, CO, acid and hydrocarbon were identified in CTLS pyrolysis. Similar gaseous products of combustion were found at lower temperatures, whereas CO2 is the dominant product of combustion at higher temperatures. Combustion was found to be better for disposal of CTLS than pyrolysis.