Design and assessment of an energy self-supply process producing tetraethyl orthosilicate using rice husk

Combusting rice husk (RH) generates energy and rice husk ash (RHA) containing high amount of silica. Recent studies showed RHA can directly react with ethanol for producing tetraethyl orthosilicate (TEOS), an important substance for different industries. Nevertheless, this process requires an intensive energy supply. This study aims to design and evaluate an energy self-supply process producing TEOS using RH for feasibility. A process simulator was used to design the target process. The simulation results revealed that RH combustion can completely meet the RHA and high energy demands of TEOS production. The economic and environmental benefits were thoroughly evaluated and compared with processes using conventional raw materials (i.e., Si_mg and silica). The evaluation results showed that using RH for TEOS production could reduce CO₂ emissions substantially. Large economic benefit was gained when renewable electricity was co-generated and sold to the power grid as a surplus.