Integrated gasification combined cycle (IGCC) is one of the most advanced power generation technologies. The normal approach to design a commercial size pressurised fluidised bed gasifier (PFBG) for IGCC is based on large-scale pilot plant experimentation or scale-up of hydrodynamically similar cold model. The conical distributor is a critical component of PFBG, which affects the hydrodynamic performance of the fluidiser. A correlation to bring out the effect of distributor apex angle a on fluidisation quality has been developed and presented in this paper. The correlation has been validated with that of Antoni Lucas et al. [1]. The average deviation and standard deviations of the correlation are 6.8 and 27%, respectively. The experimental results show that minimum fluidising velocity increases with increase in a. The bed voidage derived from Ergun's equation is found to decrease with increase of a indicating better fluidisation quality. This paper aims to study the fluidisation characteristics of cylindrical fluidised bed reactors with varying apex angle of conical distributor and derive a correlation of Reynolds number at minimum fluidising velocity as a function of Archimedes number and apex angle of the distributor. © 2009 Copyright Taylor and Francis Group, LLC.