Air gasi®cation of rice husk in a dual distributor type ¯uidized bed gasi®er K.G. Mansaray a , A.E. Ghaly a, *, A.M. Al-Taweel b , F. Hamdullahpur c , V.I. Ugursal c a Biological Engineering Department, Dalhousie University, P.O. Box 1000, Halifax, Nova Scotia, Canada, B3J 2X4 b Chemical Engineering Department, Dalhousie University, P.O. Box 1000, Halifax, Nova Scotia, Canada, B3J 2X4 c Mechanical Engineering Department, Dalhousie University, P.O. Box 1000, Halifax, Nova Scotia, Canada, B3J 2X4 Received 1 December 1998; received in revised form 21 April 1999; accepted 22 April 1999 Abstract In this study, a dual distributor type ¯uidized bed gasi®er was used for the air gasi®cation of rice husk in view of producing fuel gas. The eects of varying ¯uidization velocity (0.22, 0.28 and 0.33 m s À1 ) and equivalence ratio (0.25, 0.30 and 0.35) on the gasi®er performance were discussed. The steady state temperature varied between 665 and 8308C. The ¯uidization velocity of 0.22 m s À1 and equivalence ratio of 0.25 appeared to be the optimum conditions with respect to the quality of gas. The mole fractions of the combustible components reached their maximum values at these conditions with a typical gas composition of 4% H 2 , 5% hydrocarbons (CH 4 ,C 2 H 2 ,C 2 H 4 and C 2 H 6 ), 15% CO 2 , 20% CO and 57% N 2 . The higher heating value of the gas obtained at these ¯uidization velocity and equivalence ratio (3.09±5.03 MJ Nm À3 ) compared very well with published data from air-blown biomass gasi®ers of similar scale of operation. The gas yield and carbon conversion were in the range of 1.30 to 1.98 Nm 3 kg À1 and 55.0 to 81.0%, respectively. # 1999 Elsevier Science Ltd. All rights reserved. Keywords: Rice husk; Gasi®cation; Fluidized bed; Equivalence ratio; Fluidization velocity; Gas composition; Higher heating value; Gas yield; Carbon conversion 1. Introduction The prospect of producing clean, sustainable power in substantial quantities from agricultural residues is now arousing interest worldwide, stimulated by increasing concern over the en- vironmental consequences of conventional fossil and nuclear fuel use. An agricultural residue that could be utilized in a large number of countries for the recovery of energy because of its reason- ably high energy content (12±18 MJ/kg) is rice husk. Large quantities of rice husks are generated annually as the major by-product in the rice milling industry. The total annual rice production Biomass and Bioenergy 17 (1999) 315±332 0961-9534/99/$ - see front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0961-9534(99)00046-X www.elsevier.com/locate/biombioe * Corresponding author. Tel.: +1 902 494 6014; fax: +1 902 423 2423. E-mail address: abdel.ghaly@dal.ca (A.E. Ghaly)