Research On Steam Methane Reforming Hydrogen Production System Coupling To HTGR

Utilizing nuclear energy massive and high-efficient hydrogen production can be realized with carbon dioxide emission eliminated or mitigated. This will provided a solid base for the future sustainable energy system. Research on steam methane reforming hydrogen production system coupling to HTGR has been carried out in this thesis with the method of theoretical analysis and numerical simulation.Firstly, this paper presents the analysis of the thermal efficiency of the system by equibrium model. The global reaction for the incomplete reaction model is introduced. An analytical expression of the thermal efficiency is developed using the global reaction. With this analytical expression and equilibrium model the performance of the system is investigated. Given the reforming temperature, pressure and steam-to-carbon ratio, the thermal efficiency can be calculated. The analysis shows the system should be operated with higher steam-to-carbon ratio than that of the conventional hydrogen production system to obtain maximum thermal efficiency. The maximum value is 68.9% within the range of the reforming pressure greater than 1MPa and steam-to-carbon ratio greater than 2. The by-product carbon monoxide and the latent heat of extra steam should be utilized further to improve the system efficiency.Considering the kinetics of reaction a steady-state model of the system is developed based on the pseudo-homogeneous one-dimensional model. Good agreement is shown between the simulating results and experimental data. The results show the design of the helium-heated reformer coupling to HTR-10 is reasonable. The influence of main process parameters on the performance with respect to the methane conversion and the hydrogen yield is investigated and discussed.For the purpose of safety analysis, the transient-state models of the reformer, steam generator and heat exchanger are set up. The transient-state model of the whole system is formed by directly coupling these models together. The simulating results and experimental data fit very well. The accident of the feed gas suspension of the hydrogen production coupling to HTR-10 is analyzed. The results show the steam generator at the downstream of the reformer can effectively restrain the helium temperature fluctuation introduced by the thermal disturbance.Finally, membrane separation technology is considered in the hydrogen production system. Thermodynamics analysis of the system integrated with membrane separation technology is carried out. Based on the steady-state model of the helium-heated reformer developed above, a steady-state model has been developed for the helium-heated inorganic membrane reformer. The investigated results show that the average heat flux of helium-heated inorganic membrane reformer is 25% higher than that of conventional one. Methane conversion rate of the helium-heated inorganic membrane reformer can reach 95% while the pressure loss increases a little. With thin membrane thickness or high sweep ratio, methane conversion rate increases with high reforming pressure. This enable unfavorable condition of high pressure introduced by HTGR to steam-reforming methane hydrogen production system became favorable.