Flame Stability and Combustion Characteristics in Catalytic Micro-combustors

Junjie Chen, Deguang Xu

Abstract


The flame stability and combustion characteristics in catalytic micro-combustors were studied using an elliptic two-dimensional computational fluid dynamics model that includes detailed homogeneous and heterogeneous chemical reaction schemes, heat conduction in the solid wall, surface radiation heat transfer, and external heat losses. Simulations were carried out to investigate the effects of wall thermal conductivity, wall thickness, inlet velocity, and operating conditions on combustion characteristics and the steady-state, self-sustained flame stability of hydrogen-air mixtures. Simulation results reveal that the reaction is limited by heat transfer near the entrance and by mass transfer further downstream, despite the small scales of this system. Large transverse and axial gradients are observed even at these small scales under certain conditions. Wall thermal conductivity and thickness are very important as they determine the upstream heat transfer, which is necessary for micro-flame ignition and stability, and the material's integrity by controlling the existence of hot spots. Wall thermal conductivity is vital in determining the flame stability of the system, as the walls are responsible for the majority of the upstream heat transfer as well as the external heat losses. Thin walls exhibit large axial temperature gradients, resulting in hot spots. Thicker walls have a large cross-sectional area, which allows for greater heat transfer and more uniform, lower temperatures. Inlet velocity plays a competing role in flame stability. Low flow velocities result in reduced power generation, and high flow velocities decrease the convective timescale below that of the upstream heat transfer through the walls. There exists a range of flow velocities that allow stabilized combustion in catalytic micro-combustors.


Full Text:

PDF

References


J.A. Federici, D.G. Norton, T. Brüggemann, K.W. Voit, E.D. Wetzel, andD.G. Vlachos. 2006. Catalytic microcombustors with integrated thermoelectric elements for portable power production. Journal of Power Sources, Volume 161, Issue 2, Pages 1469-1478.

E.D. Tolmachoff, W. Allmon,and C.M. Waits. 2014. Analysis of a high throughput n-dodecane fueled heterogeneous/homogeneous parallel plate microreactor for portable power conversion. Applied Energy, Volume 128,Pages 111-118.

A. Brambilla, M. Schultze, C.E. Frouzakis, J. Mantzaras, R. Bombach, and K. Boulouchos. 2015. An experimental and numerical investigation of premixed syngas combustion dynamics in mesoscale channels with controlled wall temperature profiles. Proceedings of the Combustion Institute, Volume 35, Issue 3, Pages 3429-3437.

T.A. Wierzbicki, I.C. Lee, andA.K. Gupta. 2014. Combustion of propane with Pt and Rh catalysts in a meso-scale heat recirculating combustor. Applied Energy, Volume 130, Pages 350-356.

X. Zheng and J. Mantzaras. 2014. An analytical and numerical investigation of hetero-/homogeneous combustion with deficient reactants having larger than unity Lewis numbers. Combustion and Flame, Volume 161, Issue 7,Pages 1911-1922.

D.G. Norton, E.D. Wetzel, and D.G. Vlachos. 2006. Thermal management in catalytic microreactors. Industrial & Engineering Chemistry Research, Volume 45, Issue 1, Pages 76-84.

A.D. Benedetto, V.D. Sarli, and G. Russo.2010. Effect of geometry on the thermal behavior of catalytic micro-combustors. Catalysis Today, Volume 155, Issues 1-2, Pages 116-122.

R. Sui, N.I. Prasianakis, J. Mantzaras, N. Mallya, J. Theile, D. Lagrange, and M. Friess. 2016. An experimental and numerical investigation of the combustion and heat transfer characteristics of hydrogen-fueled catalytic microreactors. Chemical Engineering Science, Volume 141, Pages 214-230.

D.G. Nortonand D.G. Vlachos. 2005. Hydrogen assisted self-ignition of propane/air mixtures in catalytic microburners. Proceedings of the Combustion Institute, Volume 30, Issue 2, Pages 2473-2480.

M. Schultze, J. Mantzaras, R. Bombach, and K. Boulouchos. 2013. An experimental and numerical investigation of the hetero-/homogeneous combustion of fuel-rich hydrogen/air mixtures over platinum. Proceedings of the Combustion Institute, Volume 34, Issue 2, Pages 2269-2277.

G. Bagheri and S.E. Hosseini. 2015. Impacts of inner/outer reactor heat recirculation on the characteristic of micro-scale combustion system. Energy Conversion and Management, Volume 105, Pages 45-53.

Y. Wang, Z. Zhou, W. Yang, J. Zhou, J. Liu, Z. Wang, and K. Cen. 2010. Combustion of hydrogen-air in micro combustors with catalytic Pt layer. Energy Conversion and Management, Volume 51, Issue 6, Pages 1127-1133.

V.L. Zimont. 2015. Theoretical study of self-ignition and quenching limits in a catalytic micro-structured burner and their sensitivity analysis. Chemical Engineering Science, Volume 134, Pages 800-812.

S.E. Hosseini and M.A. Wahid. 2014. Investigation of bluff-body micro-flameless combustion. Energy Conversion and Management, Volume 88, Pages 120-128.

L. Merotto, C. Fanciulli, R. Dondè, and S. De Iuliis. 2016. Study of a thermoelectric generator based on a catalytic premixed meso-scale combustor. Applied Energy, Volume 162, Pages 346-353.

S.W. Jeon, W.J. Yoon, M.W. Jeong, and Y. Kim. 2014. Optimization of a counter-flow microchannel reactor using hydrogen assisted catalytic combustion for steam reforming of methane. International Journal of Hydrogen Energy, Volume 39, Issue 12, Pages 6470-6478.

M. Schultze and J. Mantzaras. 2013. Hetero-/homogeneous combustion of hydrogen/air mixtures over platinum: Fuel-lean versus fuel-rich combustion modes. International Journal of Hydrogen Energy, Volume 38, Issue 25, Pages 10654-10670.

Fluent 6.3 User's Guide.2006. Fluent Inc., Lebanon, New Hampshire.

O. Deutschmann, L.I. Maier, U. Riedel, A.H. Stroemman, and R.W. Dibble. 2000. Hydrogen assisted catalytic combustion of methane on platinum. Catalysis Today, Volume 59, Issues 1-2, Pages 141-150.

M.P. Burke, M. Chaos, Y. Ju, F.L. Dryer, and S.J. Klippenstein. 2012. Comprehensive H2/O2 kinetic model for high-pressure combustion. International Journal of Chemical Kinetics. Volume 44, Issue 7, Pages 444-474.

Y. Ghermay, J. Mantzaras, R. Bombach, and K. Boulouchos.2011. Homogeneous combustion of fuel-lean H2/O2/N2 mixtures over platinum at elevated pressures and preheats. Combustion and Flame, Volume 158, Issue 8, Pages 1491-1506.

R.J. Kee, F.M. Rupley, E. Meeks, and J.A. Miller. CHEMKIN-III: A Fortran chemical kinetics package for the analysis of gas-phase chemical and plasma kinetics, Report No. SAND96-8216, Sandia National Laboratories, 1996.

M.E. Coltrin, R.J. Kee, F.M. Rupley, and E. Meeks.1996. SURFACE CHEMKIN-III: A Fortran package for analyzing heterogeneous chemical kinetics at a solid-surface - gas-phase interface, Report No. SAND96-8217, Sandia National Laboratories.

R.J. Kee, G. Dixon-Lewis, J. Warnatz, M.E. Coltrin, J.A. Miller, and H.K. Moffat. 1998. A Fortran computer code package for the evaluation of gas-phase, multicomponent transport properties, Report No. SAND86-8246B, Sandia National Laboratories.

S.A. Smyth and D.C. Kyritsis. 2012. Experimental determination of the structure of catalytic micro-combustion flows over small-scale flat plates for methane and propane fuel. Combustion and Flame, Volume 159, Issue 2, Pages 802-816.

S. Karagiannidis and J. Mantzaras. 2010. Numerical investigation on the start-up of methane-fueled catalytic microreactors. Combustion and Flame, Volume 157, Issue 7, Pages 1400-1413.

D.H. Um, T.Y. Kim, and O.C. Kwon.2014. Power and hydrogen production from ammonia in a micro-thermophotovoltaic device integrated with a micro-reformer. Energy, Volume 73, Pages 531-542.

F. Bianco, S. Chibbaro, and G. Legros. 2015. Low-dimensional modeling of flame dynamics in heated microchannels. Chemical Engineering Science, Volume 122, Pages 533-544.

G. Pizza, J. Mantzaras, C.E. Frouzakis, A.G. Tomboulides, and K. Boulouchos. 2009. Suppression of combustion instabilities of premixed hydrogen/air flames in microchannels using heterogeneous reactions. Proceedings of the Combustion Institute, Volume 32, Issue 2, Pages 3051-3058.

D.G. Norton and D.G. Vlachos. 2003. Combustion characteristics and flame stability at the microscale: a CFD study of premixed methane/air mixtures. Chemical Engineering Science, Volume 58, Issue 21, Pages 4871-4882.

D.G. Norton and D.G. Vlachos. 2004. A CFD study of propane/air microflame stability. Combustion and Flame, Volume 138, Issues 1-2, Pages 97-107.

J.A. Federici and D.G. Vlachos. 2008. A computational fluid dynamics study of propane/air microflame stability in a heat recirculation reactor. Combustion and Flame, Volume 153, Issues 1-2, Pages 258-269.

C.H. Kuo and P.D. Ronney. 2007. Numerical modeling of non-adiabatic heat-recirculating combustors. Proceedings of the Combustion Institute, Volume 31, Issue 2, Pages 3277-3284.

E. Miyata, N. Fukushima, Y. Naka, M. Shimura, M. Tanahashi, and T. Miyauchi. 2015. Direct numerical simulation of micro combustion in a narrow circular channel with a detailed kinetic mechanism. Proceedings of the Combustion Institute, Volume 35, Issue 3, Pages 3421-3427.

A.D. Stazio, C. Chauveau, G. Dayma, and P. Dagaut.2016. Combustion in micro-channels with a controlled temperature gradient. Experimental Thermal and Fluid Science, Volume 73, Pages 79-86.

Y. Yan, W. Tang, L. Zhang, W. Pan, and L. Li. 2014. Thermal and chemical effects of hydrogen addition on catalytic micro-combustion of methane-air. International Journal of Hydrogen Energy, Volume 39, Issue 33, Pages 19204-19211.

Y.-H. Li, G.-B. Chen, F.-H. Wu, H.-F. Hsieh, and Y.-C. Chao. 2016. Effects of carbon dioxide in oxy-fuel atmosphere on catalytic combustion in a small-scale channel. Energy, Volume 94,Pages 766-774.

Y.-H. Li, G.-B. Chen, F.-H. Wu, T.-S. Cheng, and Y.-C. Chao. 2012. Effects of catalyst segmentation with cavities on combustion enhancement of blended fuels in a micro channel. Combustion and Flame, Volume 159, Issue 4, Pages 1644-1651.

C. Cao, N. Zhang, X. Chen, and Y. Cheng. 2015. A comparative study of Rh and Ni coated microchannel reactor for steam methane reforming using CFD with detailed chemistry. Chemical Engineering Science, Volume 137,Pages 276-286.

Z. Zhang, W. Yuan, J. Deng, Y. Tang, Z. Li, and K. Tang. 2016. Methanol catalytic micro-combustor with pervaporation-based methanol supply system. Chemical Engineering Journal, Volume 283, Pages 982-991.

S.A. Fanaee and J.A. Esfahani. 2014. Two-dimensional analytical model of flame characteristic in catalytic micro-combustors for a hydrogen-air mixture. International Journal of Hydrogen Energy, Volume 39, Issue 9, Pages 4600-4610.

K. Bijjula and D.C. Kyritsis. 2011. Experimental investigation of the reactive flow field around catalytic micro-wires for intermediate Reynolds-number flows. Combustion and Flame, Volume 158, Issue 6, Pages 1117-1128.

Y. Liu, A. Fan, H. Yao, and W. Liu. 2015. Numerical investigation of filtration gas combustion in a mesoscale combustor filled with inert fibrous porous medium. International Journal of Heat and Mass Transfer, Volume 91, Pages 18-26.

A.W. Fan, J.L. Wan, K. Maruta, H. Yao, and W. Liu. 2013. Interactions between heat transfer, flow field and flame stabilization in a micro-combustor with a bluff body. International Journal of Heat and Mass Transfer, Volume 66, Pages 72-79.

W.M. Yang, S.K. Chou, C. Shu, Z.W. Li, and H. Xue. 2002. Combustion in micro-cylindrical combustors with and without a backward facing step. Applied Thermal Engineering, Volume 22, Issue 16, Pages 1777-1787.

T. Kamijo, Y. Suzuki, N. Kasagi, and T. Okamasa. 2009. High-temperature micro catalytic combustor with Pd/nano-porous alumina. Proceedings of the Combustion Institute, Volume 32, Issue 2, Pages 3019-3026

J. Kariuki and R. Balachandran. 2010. Experimental investigation of dynamics of premixed acetylene-air flames in a micro-combustor. Experimental Thermal and Fluid Science, Volume 34, Issue 3, Pages 330-337.

A. Fan, S. Minaev, E. Sereshchenko, R. Fursenko, S. Kumar, W. Liu, and K. Maruta.2009. Experimental and numerical investigations of flame pattern formations in a radial microchannel. Proceedings of the Combustion Institute, Volume 32, Issue 2, Pages 3059-3066.


Refbacks

  • There are currently no refbacks.