MATHEMATICAL-MODELING OF CONTINUOUS UPDRAFT GASIFICATION OF BUNDLED JUTE STICK - A LOW ASH CONTENT WOODY BIOMASS

A jute-stick gasification process was studied at steady-state conditions in a laboratory moving-bed updraft system. An insulated cylindrical MS reactor of constant i.d. 76 mm, length 1500 mm above the grate and 150 mm below the grate, was used as gasifier, including an ash disposal unit. Results were obtained for various flow conditions with superficial velocities of air ranging from 0.0337 to 0.1011 m/s at STP. Accordingly, jute-stick superficial mass rates varied from 0.0255 to 0.0755 kg/(m(2)/s). The heating value of the producer gas was found to be in the range 4106-4689 kJ/Sm-3. The reactions taking place in the oxidation and reduction zones were formulated using a shrinking-core, diffusion-controlled mechanism in the developed non-equilibrium model. Governing equations were solved using a numerical technique. Experimental results were in agreement with the model predictions within the range of operation.