| Summary: | 博士 === 國立成功大學 === 航空太空工程學系碩博士班 === 100 === Dry auto-thermal reforming (DATR) from biomass derived gas (BDG) under excess enthalpy design concepts with porous medium (PM) is investigated in this study. The reaction zone of the porous media arrangement combines the benefits from both porous media and catalyst, such as enhancing the preheating reactant by heat transfer and improving hydrogen-rich syngas production with the surface reaction of the catalyst. Therefore, the excess enthalpy on reforming reaction could be achieved by internal heat recirculation. In the experimental process. It is used by photographic observation, infrared thermal image analysis, products concentration analysis and temperature measurements in catalyst packed-bed by obtaining temperature distribution and images information. The experimental was also matched with the control parameters to understand the heat transfer path, rapid cold processing and operational range of DATR in PM-catalyst hybrid packed-bed. Controlled parameters included CO2/CH4, O2/CH4, catalyst specification, catalyst inlet temperature, gas hourly space velocity and porous medium specification. The experimental results demonstrated that it not only supplied the energy required for self-sustained reaction, but also avoided the coke formation by dry auto-thermal reforming. It has a wide operation region to maintain the moderate production of the syngas. Moreover, the reforming reaction with the hybrid reformer could achieve excess enthalpy under the tested parameters. Therefore, the temperature measurement along the axial position and image observation of the catalyst packed-bed indicated that the porous media arrangement may have been helpful to the uniformity of gas distribution to decrease the gradients of temperature and concentration in the reaction chamber. The peak temperature can thus be stabilized at the interface of the PM and catalyst bed, significantly improving the propagation and stability of the flame. OBSiC (Oxide-bonded silicon carbide) with excellent thermal shock resistance was selected for the excess enthalpy reforming reaction. Furthermore, the operational boundary of DATR indicates that the reforming parameters are primarily limited to the carbon formation zone, the endothermic reaction zone, and the catalyst sintering zone. Operational boundaries are also slightly offset with the heat release rates. Therefore, the selection of the parameters was determined to achieve high reforming efficiency and low energy loss percentage. The results showed that the energy loss percentage was between 12.7% to 24.6% and reforming efficiency was between 64.4% to 79.5% with the best reforming parameter settings (O2/CH4=0.7 to 0.9 and CO2/CH4=0.0 to 2.0). Finally, the experimental results demonstrated that PM-catalyst hybrid design can improve reforming efficiently. It can be applied to set-based thermal power systems and convert the pollution emissions (CO2-rich gas) of mobile vehicles in real time.
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