Conversion of cotton cocoon shell to hydrogen rich gaseous products by pyrolysis Atila C ß a glar, Ayhan Demirbas ß * P.K. 216, TR61035 Trabzon, Turkey Received 13 October 2000; accepted 19 February 2001 Abstract Hydrogen from solid wastes is produced by pyrolysis. In this study, cotton cocoon shell samples were subjected to direct and catalytic pyrolysis to obtain hydrogen rich gaseous products at desired tempera- tures. The samples, both untreated and impregnated with catalyst, were pyrolyzed at 775, 850, 925, 975 and 1025 K temperatures. The total volume and the yield of gas from both pyrolyses increase with increasing temperature. The largest hydrogen rich gas yield obtained from cotton cocoon shell, using about 13% ZnCl 2 as catalyst at about 1025 K temperature, is 59.9%. In general, in the pyrolysis of cotton cocoon shell, the yield of hydrogen rich gaseous product increases with ZnCl 2 catalyst, but the yield of pyrolytic gas decreases in spite of increasing the yield of charcoal and liquid products. The catalytic eect of Na 2 CO 3 was greater than that of K 2 CO 3 for the cotton cocoon shell, especially in low temperature pyrolysis runs. Ó 2001 Elsevier Science Ltd. All rights reserved. Keywords: Cotton cocoon shell; Hydrogen rich gas products; Conversion; Pyrolysis 1. Introduction Biomass is the fourth largest source of energy in the world, supplying about 14% of primary energy [1,2]. Pyrolysis is the thermochemical process that converts biomass into liquid, charcoal and non-condensable gases, acetic acid, acetone and methanol by heating the biomass to about 750 K in the absence of air [3,4]. In an earlier study [5], using hydrogen as an attractive fuel in the future and obtaining hydrogen from fossil and non-fossil energy sources was comprehensively investigated. Future energy Energy Conversion and Management 43 2002) 489±497 www.elsevier.com/locate/enconman * Corresponding author. Fax: +90-0462-248-7344. E-mail address: ayhandemirbas@hotmail.com A. Demirbas ß). 0196-8904/02/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII:S0196-890401)00037-1