||This study aims to construct a high-temperature catalytic heat-recirculating combustor using a Swiss-roll burner (SRB) and a high temperature Sr0.8La0.2MnAl11O19-α catalyst, which features high-efficiency and near-zero [NOx] emissions. Fuels are premixed methane/air mixtures at different equivalence ratios (φ), which are used in a 1.5-turn SRB for the performance test, including measurements of temperature distributions inside the SRB, heat-recirculation rate (HR), concentrations of emissions (NOx and CO), etc. Then, a new reaction platform is designed to quantitatively investigate various characteristics of such high-temperature Sr0.8La0.2MnAl11O19-α catalyst, from its preparation and production to the effect of φ, from temperature variations before and after the honeycomb catalytic sector to the effect of space velocity (SV), and from the degradation of the surface area of such catalyst after long time operation to measurements of emissions. The goal is to combine the above two technologies to design a high-temperature, high-efficient, very-low-NOx burner. The time evolution of temperature distributions inside the SRB are measured using as many as eleven K- and R-type thermocouples for which these data are recorded by a PCLD-818 data acquisition card an a GeniDAQ software at a sampling rate of 1 Hz. Emissions are measured by the standard flue-gas analyzer. The photographs and surface area of the high-temperature catalyst are obtained from the Scanning Electron Microscopy (SEM) and the Accelerated Surface Area and Porosimetry System (ASAP). Results for φ=0.5 reveal that all measured temperature data at various positions of the SRB increase with increasing Ref (Ref=VfDin/ν) increases from 370 to 980, where Vf, Din, and ν are the supply reactant velocity, the SRB channel width, and the kinematic viscosity of reactants, respectively. The highest temperature at various Ref and all occurs near a previously-designed flame holder in the central combustion chamber, confirming the flame holding feature for stable combustion in the center of the SRB. Furthermore, the HR of the SRB is found to be increased with Ref as well. Concerning the high-temperature catalyst, the initial temperature (To) condition to start up the high-temperature catalyst at φ=1.3 is To=500oC. Temperature measurements show that the temperature after the high-temperature catalyst (Tc-out) increases from 1,050oC to 1,300oC when values of SV increase from 76,000 1/h to 465,000 1/h. However, when values of SV are larger or equal to 310,000 1/h, Tc-out not only ceases its increase but also decreases slightly. Values of [NOx] and [CO] are only 1.9 and 2.1 ppm when SV=76,000 1/h. Even for SV=465,000 1/h, values of [NOx] and [CO] are all below 12 ppm. The longevity test of the high-temperature catalyst at φ=0.5, To=500oC, and SV=76,000 1/h show that the surface area of the catalyst would decrease from its initial value 25 m2/g to 5~8 m2/g when about 52 operation hours are applied. Finally, we use the SRB as a pre-heater to burn first rich CH4/air mixtures (φ=1.3), so that its high temperature off-gas (To>500oC) with remaining CH4/air fuels can be further reacted in the high-temperature honeycomb catalytic sector. This new device is believed to be of useful in gas turbine applications and in dealing with many industrial off-gas fuels. Thus, the goals of saving energy and reducing pollutants can be achieved.|
||Ahn, J., Eastwood, C., Sitzki, L. & Ronney, P. D. 2005 Gas-phase and catalytic combustion in heat-recirculating burners. Proc. Combust. Inst. 30, 2463-2472.|
Chen, M. & Buckmaster, J. 2004 Modelling of combustion and heat transfer in ‘Swiss-roll’ micro-scale combustors. Combust. Theory Modelling 8, 701-720.
Ersson, A. G., Johansson, E. M. & Järås, S. G. 1998 Techniques for preparation of manganese-substituted lanthanum hexaaluminates. Preparation of catalyst 7, 601-608.
Jugjai, S. & Rungsimuntuchart, N. 2002 High efficiency heat-recirculating domestic gas burners. Exp. Thermal Fluid Sci. 26, 581-592.
Kuo, C. H. & Ronney, P. D. 2006 Numerical modeling of heat recirculating combustors. to appear in Proc. Combust. Inst. 31.
Kim., N., Kato. S., Kataoka. T., Yokomori. T., Maruyama. S., Fujimori. T. & Maruta. K. 2005 Flame stabilization and emission of small Swiss-roll combustors as heaters. Combust. Flame 141, 229-240.
Kikuchi, R., Tanaka, Y., Sasaki, K. & Eguchi, K. 2003 High temperature catalytic combustion of methane and propane over hexaaluminate catalysts: NOx emission characteristics. Cataly. Today 83, 233-231.
Lloyd, S. A. & Weinberg, F. J. 1974 A burner for mixtures of very low heat content. Nature 251, 47-49.
Lloyd, S. A. & Weinberg, F. J. 1975 Limits to energy release and utilization from chemical fuels. Nature 257, 367-370.
Machida, M., Kawasaki, H., Eguchi, K. & Arai, H. 1988 Surface areas and catalytic activities of Mn-substituted hexaaluminates with various cation compositions in the mirror plane. Chem. Lett. 17, 1461-1464.
Maruta, K., Takeda, K., Sitzki, L., Borer, K. & Ronney, P. D. 2001 Catalytic combustion in microchannel for MEMS power generation. Proceedings of 3rd Asia-Pacific Conference on Combustion, June 24-27, Seoul, Korea, 219-222.
Pfefferle, W. C., Heck, R. M., Carrubba, R. M. & Roberts, G. W. 1975 Catathermal combustion: a new process for low-emission fuel conversion. ASME Paper 75-WA/Fu-1.
Pfefferle, W. C. & Pfefferle, L. D. 1986 Catalytically stabilized combustion. Prog. Energ. Combust. Sci. 12, 25-41.
Pfefferle, L. D. & Pfefferle, W. C. 1987 Catalysis in combustion catalysis. Reviews-Science and Engineering 29, 219-267.
Rostrupnielsen, J. R. & Hansen, J. H. B. 1993 CO2-Reforming of Methane over Transition Metals. J. Catal. 144, 38-49.
Rowe, D. M. 1999 Thermoelectrics, an environmentally-friendly source of electrical power. Renew. Energ. 16, 1251-1256.
Schaevitz, S. B., Franz, A. J., Jensen, K. F. & Schmidt, M. A. 2001 A combustion-based mems thermoelectric power generator. The 11th International Conference on Solid-State Sensors and Actuators, June 10-14, Munich, Germany.
Sinoda, M., Tanaka, R. & Arai, N. 2002 Optimization of heat transfer performances of a heat-recirculating ceramic burner during methane/air and low-calorific-fuel/air combustion. Energ. Convers. Manage. 43, 1479-1491.
Sitzki, L., Borer, K., Schuster, E. & Ronney, P. D. 2001a Combustion in microscale heat-recirculating burner. The 3rd Asia-Pacific Conference on Combustion, June 24-27, Seoul, Korea, 473-476.
Tanaka. R., Sinoda, M. & Arai, N., 2001 Combustion characteristics of a heat-recirculating ceramic burner using a low-calorific-fuel Energ. Convers. Manage. 42, 1897-1907.
Weinberg, F. J. 1986 Advanced Combustion Methods, Academic Press.
Weinberg, F. J., Rowe, D. M., Min, G. & Ronney, P. D. 2002 On thermoelectric power conversion from heat re-circulating combustion systems. Proc. Combust. Inst. 29, 957-963.
吳昇哲 2003 小型熱再循環觸媒燃燒器之實驗研究及應用，國立中央大學機械工程研究所，碩士論文。
楊竣傑 2004 氫能利用：過焓觸媒熱電產生器之實作研究，國立中央大學機械工程研究所，碩士論文。
鄭偉隆 2005 低氮氧化物燃燒器實驗和數值研究及其應用，國立中央大學機械工程研究所，碩士論文。