| Hydrogen energy is a kind of clean energy,which has the characteristics of wide sources and high calorific value of combustion.In addition,only water is produced in the combustion process,which is pollution-free and conforms to the development direction of new energy in the future.However,its further development has been restricted by hydrogen storage and transportation.Methanol is the most suitable fuel for the reaction of methanol reforming due to its mild reaction conditions,low carbon content and high hydrogen production.In present paper,a reforming microreactor with grooved methanol for hydrogen production is designed,and the effect of different design parameters on the performance of the methanol reforming reactor is studied through theoretical analysis,numerical simulation and experimental methods.（1）Based on the finite rate chemical reaction model,the numerical model of methanol reforming hydrogen production microreactor was established,and the grid independent verification was performed to eliminated the effect of the number of grids on the numerical simulation results.Under the same operating conditions,the numerical simulation results were compared with the existing experimental values to verify the accuracy of the model,and the errors were within a reasonable range（≤5%）.（2）Numerical simulation was used to study the heat and mass transfer performance of rectangular grooved microreactor.Through the analysis of overall performance,the mole fraction,temperature distribution diagram and curve diagram of each component in the center of the reaction channel in the rectangular groove microreactor were obtained,and the relationship between the heat transfer process and reactant gas flow in the microreactor was analyzed in detail.The effects of different feed rates,water alcohol ratios and thermal conductivity of solid wall on heat and mass transfer performance of rectangular grooved microreactor were further investigated.It was found that selecting appropriate parameters is of great significance to maintain efficient coupling of heat and stability of performance in the microreactor.（3）In order to further optimize the grooved shape,three different groove microreactors were designed,namely smooth straight-channel,rectangular grooved microreactors and trapezoidal groove microreactors.The heat and mass transfer performance of microreactors for hydrogen production by methanol reforming with different grooves under different thermodynamic parameters（water-alcohol ratios,inlet temperatures and feed rates）was studied by numerical simulation.The results showed that the trapezoidal groove microreactor has the best hydrogen production performance compared with the other ones（smooth straight-channel and rectangular groove microreactors）.For the microreactor with trapezoidal grooves,when the combustion channel feed rate is 4m/s,reforming channel feed rate is 13m/s,water-alcohol ratio is1.75,reaction temperature is 373K,and equivalent ratio is 0.8,methanol conversion rate can be achieved up to 98.03%and hydrogen yield rate can be achieved up to 41.76%.Compared with smooth straight path,it is respectively increased by 25.45%and 18.04%.（4）The experimental platform of methanol reforming hydrogen production microreactor was built.The technology of gas chromatography was adapted.The performance of the reforming reactor was evaluated by methanol conversion,hydrogen selectivity and various performance coefficients.Under different operating parameters,the experimental values were compared with the simulation results to verify the accuracy of the numerical model.The results showed that methanol conversion and hydrogen selectivity increase with the increase of reaction temperature,but the higher the reaction temperature is not the better,too high reaction temperature could lead to catalyst deactivation,affecting the performance of microreactor;With the increase of water-alcohol ratio,methanol conversion gradually increases,while hydrogen and CO contents gradually decrease;With the increase of space velocity,methanol conversion gradually decreases,and hydrogen selectivity have opposite trends.Under the operating conditions of reaction temperature 250,water to alcohol ratio 1.5 and space velocity 10.4h-1,the methanol steam reforming hydrogen microreactor can maintain the best performance.Strict control of operating conditions can ensure the performance stability of methanol steam reforming hydrogen microreactor. |
