Hydrogen has received widespread attention as a new clean energy in order to reduce the carbon emissions of fuel vehicles. This paper studies a tubular microreactor based on methanol steam reforming. Methanol and steam are mixed in proportion and the chemical reaction takes place in a porous catalytic bed. For heating purposes, hot gas from the burner penetrates the reactor bed through heating tubes. Energy is supplied through the heating tubes to drive the endothermic reaction system. The microreactor is enclosed in an insulated jacket. In this paper, parameters such as methanol conversion and hydrogen concentration are evaluated by considering microreactor materials, heating gas temperature and flow direction, heating tube distribution, pressure drop and reaction channel length. First of all, choosing a microreactor material with a smaller thermal conductivity can avoid excessive heat loss, and improve heat transfer performance. Increasing the heating gas temperature leads to an increase in the temperature of the reaction zone, thereby increasing the CH3OH conversion rate and H2 mass fraction. Changing the flow direction of the heating gas affects the reaction rate, but has little effect on the reaction result. Through the research on the distribution of the heating tubes, the results show that the hydrogen production rate is higher when the contact area between the heating tubes and the reaction zone is larger. Secondly, through the comparison of the data under different pressure drops, the best parameter [Formula: see text][Formula: see text]pa is obtained, and the CH3OH conversion rate is 80.6% at this time. Finally, increasing the length of the reaction channel can make the reaction more complete. For example, when the reaction channel length [Formula: see text][Formula: see text]m, the CH3OH conversion rate is as high as 83.7%.

With the rising emission of NO and particulate matter in vehicle exhaust, the atmosphere is gradually deteriorating and human health is being impacted. In order to reduce the NO emission in automobile exhaust devices, a tubular microreactor with a Cantor structure was studied in this paper. The NO conversion rate and concentration were evaluated by considering the fractal principle, reactant concentration ratio, inlet velocity and channel temperature. Increasing the fractal dimension could promote the mixing of reactants and make the distribution of species concentration in the channel more uniform. When the NO flux at the inlet of the microreactor channel was a constant, increasing the concentration of NH 3 could significantly improve the reaction efficiency. Results show that the effect on the reaction results was best when the NO inlet velocity was lower and the NH 3 inlet velocity higher. For example, when u NO =0.025 m s −1 and u NH3 =0.05 m s −1 , the conversion rate of NO was as high as 98%. Porosity had little effect on the reaction results. Through comparison of the NO concentration at the outlet at different channel temperatures, it was concluded that increasing the temperature in the channel is most helpful in improving the reaction efficiency.