492催化學(xué)報(bào)第23卷Table 2 Parameters of the structure of the chipits rapid heat and mass transfer with its small di-HhwnnV/mlmensions.0.34 0.17 30 0.5 0.5 45 48 51.1Fig 3 shows the composition of the dry productH一Thickness of chip,h一Depth of channel , L-Length of channel，W。一Width of channel , ww一Wallgas of MATR. H2 has a high value of 43% and CH4thickness between channels, W- Width of total chan-is lower than 0.5% , while CO is higher than 15%nels , n1一Number of channel per chip , n2一Number ofunder the reaction condition. CO is the main poisonchip, V一Volume of microreactorof the electrode catalyst( Pt )of the PEMFC ,so it .TheunitofH,h,L,W,wsandwwismm.must be reduced to less than 1 X 10 . To attainfor 2 h. Second ,a wash-coat on the stainless steelthat , supplementary reactions , such as gas- waterwas made by a CeO2 ZrO2 solid solutiort 61. Finally ,shift reaction and preferential oxidation , have to bethe main active component , Pt , was added by Ptapplied. Meanwhile , novel catalyst for MATR with(NH3): ( OH》solution( 0.1 g/ml ) via dip-coat-high hydrogen selectivity should be developed toing ,and dried at 120 C , then calcined at 400 Creach this low CO concentration level.for 3 h ,and reduced with 10% H290%N2 at 400 Cfor 2 h.The molar ratios of H2O and O2 to MeOH in441)_the feed were 1.2 and 0.3 , respectively , and airwas used as oxidant. Methanol and water were pre-vaporized at 150 C，then mixed with air and en-tered the microreactor which was placed in an oven.(3)Water and methanol were removed from the exit gasby a cold trap , while the dry gas entered a GC andsoap bubble flowmeter for composition analysis and4)，flow- rate measurement respectively. The reaction146 18was carried out at 450 C.GHSV(MeOH)! 10000 h'From Fig2 ,it is clear that the methanol con-version in the monolith reactor is rapidly reduced toFig 3 Product composition s GHSV( MeOH )lower than 80% at 20000 h~1 ，while it is stillin microchannel reactor(1)H2 ,(2)0O ,(3)CO2 ,(4)CHhigher than 93% in the microchannel reactor even( The reaction condition is the same as in Fig 2)at 186000 h~ 1，which is about 10 times higherthan that in the monolith reactor. The reason is thatIn conclusion ,owing to the small characteristicthe intrinsic rate of MATR is very high ,so the ap-dimensions of the microchannel reactor , the effect ofparent reaction rate is heavily limited by mass andneat and mass transport is increased remarkably.heat transport. While the reaction rate increased re-The reaction rate increases and the methanol con-markably and the conversion is still high even atversion remains high at very high GHSV. Thehigh GHSV in the microchannel reactor , owing to miniaturization of the hydrogen generation system100can be achieved with a microchannel reactor.References(1)1 Choi Y , Stenger HG. Appl Catal B ,2002 ,384 ):25990上2TonkovichAY,ZilkaJL,LaMontMJ,WangY,We-gengRS. Chem EngSci , 1999 ,54( 13/14 ):29473 ServiceR F. Science , 1998 , 282 5388 ):400802)4 JensenKF. AIChEJ , 1999 ,45 10 ):20515WengenRS,DrostMK,BrenchleyDL.In:EhrfeldW10120ed. Proceedings of the 3rd International Conference onGHSV(MeOH)/ 10000 h'Microreaction Technology. Frankfurt , 1999.16 LiSh L,Chen G W ,SunJ L,Li H Q. Cuihua XuebaoFig 2 MeOH conversion vs GHSV( MeOH ) in different reactors( Chin J Catal ),2002 ,23( 4):341( 1 ) Microchannel reactor ,( 2 )Ceramic monolith reactor( Reactit方數(shù)據(jù): n(O2)n( MeOH)=0.304 ,θ=450 C )(EdWGZh)