This study numerically investigates methanol-steam reforming (MSR) in miniature annulus type reactors with reactant flow disturbance and hot gas flow heat supply. The reactant flow disturbance is created by placing baffle plates into an inner tube packed with catalyst particles and heated using hot gas flow in the gap between the inner and outer annulus tubes. It was found that the baffle plate increases the heat transfer area and creates flow fluctuations inside the catalyst bed, which lead to enhanced heat transfer between the hot gas and reactant flows and also leads to higher mass transfer inside the catalyst bed. The reactant flow temperature can be increased closer to the hot gas flow temperature, and the enhanced mass transfer between the catalyst particles and reactant flow stream leads to improved methanol conversion in the reformer. The pressure drop across the reactor was found to be not significantly influenced by the baffle plates in miniature scale reactors. It was also found that reducing the thermal resistance between the hot gas flow and reactant flow can further improve the methanol conversion.