Abstract: Liquid-solid circulating reactors form the heart of emerging alkylation processes for the production of motor fuel additives and also for the manufacture of linear alkyl benzene. To design a liquid-solid circulating fluidized bed system hydrodynamics be studied first but there is still limited understanding on how particles were circulated in Liquid Solid Circulating Fluidized Bed (LSCFB) with viscous fluids. The hydrodynamics characteristics of the LSCFB of varying viscosity were analysed in terms of solid circulation rate, particle velocity and pressure drop for different fluids. Experiments were conducted using water and glycerol at different concentrations with varying viscosities. Solids of different densities and diameter were used for the study. Results show that circulating fluidization regime starts earlier for higher viscous solution because of decrease in critical transitional velocity. Sand compared to glass bead showed a higher solid circulation rate under similar operating conditions. The solid circulation rate increases with increase in total velocity, auxiliary velocity and also increases with increasing viscosity.