Characterization of Coconut (Cocos nucifera) Husk and Shell for Gasification: A Study on Fouling and Slagging Tendencies
Keynty Boy V. Magtoto1, Toni-An Mae C. Salcedo2, Rossana Marie C. Amongo3, and Sergio C. Capareda4
ABSTRACT
The melting of the feedstock’s inorganic components under gasification temperatures and its subsequent deposition in the heated surfaces of a gasifier causes inefficiencies and operational problems. The study evaluated the compatibility of coconut husk (c-husk) and coconut shell (c-shell) for gasification based on biomass characterization, prediction of fouling and slagging tendencies, and determination of the ash melting point. ASTM standards were used to characterize both biomass where c-shell is found to be an appropriate feedstock for gasification because of its high volatile matter (83.5%) and bulk density (702.1 kg-m3). Slagging and fouling tendencies during thermal conversion were determined using empirical indices such as Alkali index (AI), base-to-acid ratio (Rb/a) and bed agglomeration index (BAI). Results revealed that all indices predict c-shell will not exhibit slagging and fouling but c-husk will. Moreover, slagging (Rs) and fouling (Rf) factors, which are commonly used for coals, were also used and projected that c-shell has low-slagging and medium-fouling potential while c-husk has severe-slagging and fouling potential. Furthermore, the compressive strengths of c-husk and c-shell ash pellets treated at gasification temperatures were measured to indirectly determine the temperature at which slagging and fouling is likely to occur. The ash melting temperature were determined to be less than 600°C for c-husk and greater than 900°C for c-shell. Hence, ash melting problems are expected only in c-husk gasification. C-shell, on the other hand, is found to be a suitable feedstock at typical gasification temperatures.
Keywords: ash melting temperature, coconut husk, coconut shell, gasification, fouling and slagging indices
1Assistant Professor 1, Agrometeorology and Farm Structures Division, Institute of Agricultural Engineering, College of Engineering and Agro-Industrial Technology, University of the Philippines Los Baňos, 4031 College, Laguna, Philippines
2 University Researcher, Smarter Approaches to Reinvigorate Agriculture as an Industry in the Philippines (SARAI) Project, Agrometeorology and Farm Structures Division, Institute of Agricultural Engineering, College of Engineering and Agro-Industrial Technology, University of the Philippines Los Baños, 4031 College, Laguna, Philippines.
3 Associate Professor 6, Agricultural Machinery Division, Institute of Agricultural Engineering, College of Engineering and Agro-Industrial Technology, University of the Philippines Los Baños, 4031 College, Laguna, Philippines.
4Professor, Department of Biological and Agricultural Engineering, Texas A&M University, Texas, USA.
Citation:
Magtoto, K.B., Salcedo, T.M.C., Amongo, R.M.C., and Capareda, S.C. (2019). Characterization of Coconut (Cocos nucifera) Husk and Shell for Gasification: A Study on Fouling and Slagging Tendencies. Philippine Journal of Agricultural and Biosystems Engineering, (15):27-39.