Spouted-Bed Reactor in Producing Sodium Silicate from Paddy Husk Ash: Hydrodynamics, Mass Transfer, and Silicate Yield

Johnner P. Sitompul, Chrismono Himawan & Agus Wanadri

A laboratory-scale spouted bed reactor has been applied for producing sodium silicate from paddy husk ash and NaOH. The study covered hydrodynamics, mass transfer, and silicate-yield in the reactor. The correlation of minimum superficial velocity was determined by using nonreacting paddy ash-water system. Mass transfer correlation is spouted-bed which is valid for transition regim, i.e. Reynold particle range 7-25 or Reynold fluid number 19 -254, was derived from a simple model assuming the diffusion rate of NaOH from bulk to the particle surface as a determining step. Conversion of SiO₂, equivalent to Na-silicate yield, is up to 62% using 0.8 M NaOH. This performance is significantly better than the other previous research. The study found that in producing silicate pay-off between SiO₂ conversion and SiO₂/Na₂O mol ratio should be considered.

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