Presentation on theme: "Characteristics of excess enthalpy on dry autothermal reforming from simulated biogas with porous media M.P. Lai, W.H. Lai, C.Y. Chen, S.S. Su, R.F. Horng,"— Presentation transcript:
Characteristics of excess enthalpy on dry autothermal reforming from simulated biogas with porous media M.P. Lai, W.H. Lai, C.Y. Chen, S.S. Su, R.F. Horng, W.C. Chiu, Y.M. Chang Department of Aeronautics and Astronautics, Research Center for Energy Technology and Strategy (RCETS), National Cheng Kung University, Tainan, Taiwan (R.O.C.) Department of Mechanical Engineering, Kun Shan University, Tainan, Taiwan (ROC) Reporter : Ming-Pin Lai Date : 2012/06/05 Reforming & Gasification, Biomass-1, HPB6
Conclusions Equipment details and parameters design Related literature and objective Contents Introduction and motivation Preliminary achievement Effect of excess enthalpy on reaction gas temperature Effect of porous assisted DATR on performance index
CO 2 is a valuable carbon source. The low carbon economy through chemical recycling of CO 2 with an alternative renewable energy resource (ex: Biogas, Landfill, digester gas …etc). Recycling excess CO 2 from industrial gases and mobility vehicle will mitigate a major man- flue gas exhaust gas made cause of globe warming. The flue gas and exhaust gas are attractive as waste heat for endothermic reaction. Advantage: Heating value H 2 -rich gas for power system (ICE/GT/*FC…etc) Assisting combustion (Incinerator) Syngas application Synthesis fuel ( Diesel, Gasoline, JP, DME, MeOH ) GHG reduction Mitigation, Recycle, Reuse Biogas Landfill Biomass Introduction and Motivation CO 2 mitigation and H 2 generation 1 Reforming (Thermal-chemical) CO 2 decomposition : CO 2 CO+0.5O 2 CO 2 decomposition : CO 2 CO+0.5O 2 Gasification (Boudouard) : C+CO 2 2CO Gasification (Boudouard) : C+CO 2 2CO CO 2 reforming of CH 4 : CH 4 +CO 2 2CO+2H 2 CO 2 reforming of CH 4 : CH 4 +CO 2 2CO+2H 2 Reverse water gas shifting : CO 2 +H 2 CO+H 2 O Reverse water gas shifting : CO 2 +H 2 CO+H 2 O CO 2 -Methanation : CO 2 +4H 2 CH 4 +2H 2 O CO 2 -Methanation : CO 2 +4H 2 CH 4 +2H 2 O Reduction (Photo-chemical) Synthesis ReferenceGas source Compositions (Vol. %) CH 4 CO 2 N2N2 COH2H2 H2SH2SO2O2 NH 3 RyckeboschBiogas gas < <1 SpeightBiogas gas PerssonBiogas gas DeubleinBiogas gas LaiSimulated gas Composition of biomass derived gas.
Related Literature and objective(1/2) Comparison of the T ead and T R under varying reforming parameters 2 WH Lai, MP Lai, RF Horng, Study on hydrogen-rich syngas production by dry autothermal reforming from biomass derived gas, International Journal of Hydrogen Energy, doi: /j.ijhydene
The figure shows a schematic diagram of the temperature histories of premixed combustion both without and with heat recirculation Excess enthalpy (Super-adiabatic temperature) Related Literature and objective(2/2) 3 The internal heat recirculation mechanism by heat transfer. Modified after 
Schematic of experimental arrangement Experimental details 4
Reforming parameters: Fuel feeding rate : 10 L/min-CH 4 CO 2 /CH 4 : 0, 0.33, 1 O 2 /CH 4 : 0.5, 0.75, 1.0 Reforming mode : POX, DATR Porous media specifications : Material: OBSiC, Al 2 O 3, ZrO 2, Cordierite, Fe-Cr-Al alloy Structure: Ceramic foam, Honeycomb Catalyst specifications : Active catalyst : Pt-Rh/CeO 2 -Al 2 O 3 Support : Monolith (100 cell/in 2 ) Loading amount : 50 g/ft 3 D × L : ψ 46.2*50.0 mm 2 Experimental parameter design BET Surface Area (m 2 /g) BJH desorption Pore Size (nm) t-Plot Micropore Volume (cm 3 /g) Langmuir Surface Area (m 2 /g) Relationship of O 2 /CH 4 molar ratio and reaction of enthalpy under methane reforming 5
Preliminary achievement (1/3) -Photographic observation on PM assisted DATR 6 Temperature data show for reaction in which a PM was placed, the reformate gas temperature of each position of the catalyst could be raised to 150 to 200˚C. The fire observation in the side views show that adding PM can reduce wall heat dissipation, which is accomplished mainly by using various heat transfer paths, which feed the heat stored in the wall back into the PM. Images from Table (A, D) show that reactions with a PM are able to prevent the low temperature working fluid from directly entering the catalyst reaction zone, which overcomes the problems of temperature gradients in the catalyst.
Comparison of the equilibrium adiabatic temperature and reformate gas temperature with or without PM assisting under varying reforming parameters Preliminary achievement (2/3) -Effect of excess enthalpy on reaction gas temperature 7 PM was installed in the reaction zone, their overall reaction temperatures not only effectively were improved, but could be higher than those of the EATs. However, the temperature curve also shows that the material of PM has made a little difference in the reformate gas temperature. It confirmed the view that PM can achieve the excess enthalpy on a reforming reaction. Excess enthalpy (Super-adiabatic temp.) RGT>EAT
Relationship between energy loss percentage and reforming efficiency under varying reforming parameters. 8 Preliminary achievement (3/3) -Effect of porous assisted DATR on performance index The total energy loss consisted of sensible heat energy loss carried away by the products during the oxidation. The results demonstrated that the energy loss was in the range of 8 to 31 %. Overall, those reactions with a PM installed in the reaction zone were able to attain a better reforming efficiency and reduced energy loss percentage. This allowed the methane conversion efficiency to improve effectively, increasing the production of hydrogen and carbon monoxide.
With the assistance of PM, the reformate gas temperature of the DATR could be raised, and even higher than the EAT. As a result, it need not provide the external energy to the DATR for self-sustaining reaction; although it is a strongly endothermic reaction. From the fire observation and reaction temperature measurement, it could be confirmed that the PM arrangement was helpful to preheat reactant by heat recirculation. It also contributed to the uniformity of gas distribution and thereby to decrease the gradients of temperature and concentration in the reaction chamber. Conclusions Fire observation Equilibrium adiabatic temperature 9 The reforming performance improvement could be achieved on DATR with PM assisting. The improvement in methane conversion efficiency was 18%, reforming efficiency was 33.9%, and energy loss percentage was 20.7% with the best parameter settings (CO 2 /CH 4 =1and O 2 /CH 4 =0.75) by the OBSiC foam. Reforming performance improvement
Ming-Pin, Lai Jet propulsion/Fuel cell Lab. Department of Aeronautics and Astronautics National Cheng Kung University No. 1, University Rd., Tainan City, Taiwan, R.O.C. Thanks for your attention