Cashew Nut Shells Pyrolysis:  Individual Gas Evolution Rates and Yields

• Published in: Energy & fuels Vol. 21; no. 4; pp. 2357 - 2362
• Main Authors: Tsamba, A. J, Yang, W, Blasiak, W, Wójtowicz, M. A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.07.2007
• Subjects: Activation energy; Applied sciences; Biomass; Crosslinking; Energy; Exact sciences and technology; Fourier transform infrared spectroscopy; Gaussian distribution; Hardwoods; Hulls (seed coverings); Mathematical models; Natural energy; TECHNOLOGY; TEKNIKVETENSKAP; Thermogravimetric analysis; Infrared spectrometry; Pyrolysis; Fourier transformation; Thermogravimetry; Biomass; Kinetics; Performance; Cashew nut; Vegetal waste
• ISSN: 0887-0624; 1520-5029; 1520-5029
• DOI: 10.1021/ef0604792

Cashew nut shells are one type of the most abundant biomass tropical wastes, which can be used for energy generation. However, there is lack of data for the thermal conversion process of cashew nut shells such as pyrolysis individual gas products, yields, and reaction kinetics. In this research work, the pyrolysis processes of cashew nut shells at low heating rates (10, 30, and 100 K/min) were studied. Thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer (TG-FTIR) was used. The pyrolysis product yields obtained were compared with the available data in the literature for wood and Miscanthus Giganteus. It was found that cashew nut shells have tars and volatiles at levels equivalent to those of wood pellets, both above the tar and volatile content of M. Giganteus. Further, kinetic parameters were obtained from the TG-FTIR results using an approach based on parallel independent first-order reactions with a Gaussian distribution of activation energies and following the T max method. The data obtained through this approach included the identification, kinetics, and yield of each gas product precursor. These results are then used as input files for a distributed activation energy model (DAEM) for biomass pyrolysis, based on a functional group analysis, which still does not include the devolatilization, cross-linking competitive reactions. The predicted evaluation data from this model were found to generally agree with that from TG-FTIR analysis. However, the model still demands improvement to accommodate secondary and cross-linking competitive reactions.