Post on 13-Jan-2016
description
Numerical Investigations on the Developmentof Plate Reformers: Comparison of Different
Assignments of the Chambers
• Electrically Heated Alumite Catalyst
Introduction
Model
Figuter
Reference
Result
Model verification
Reaactor
Calcination
Aluminum clad plate
Pretreatment
Anodization
Hydration treatment
Impregnation
20% H2 reduction
Ni/Al2O3/alloy catalyst
Pore widening treatment
Calcination
NaOH 3 min, HNO3 1 min
298K 2h
773K 3h in air
923K 6h
4 wt% oxalic acid solution60A∙m-2 303K 5h
4 wt% oxalic acid solution 303K 2h
353K 1h
623K 1h in air Calcination
Aluminum clad plate
Pretreatment
Anodization
Hydration treatment
Impregnation
20% H2 reduction
Ni/Al2O3/alloy catalyst
Pore widening treatment
Calcination
NaOH 3 min, HNO3 1 min
298K 2h
773K 3h in air
923K 6h
4 wt% oxalic acid solution60A∙m-2 303K 5h
4 wt% oxalic acid solution 303K 2h
353K 1h
623K 1h in air
isCombined with three layers i.e. two alumite layers (as the catalyst carrier ) and an alloy layer (high efficiency of the heat transfer, and can be heated by electricity)
Fig.1 electrically heating profile of EHAC (endurance temperature : 1273 K)
Fig.4Temperature distribution in the reactor bed by different heat-up methods (a) heat-up by heater (b) electrical heat-up through the catalyst
Model Equations
(a) (b)
Fig. 2 the scheme of the reactor( for a clarity, the scheme is not drawn in real scale) (1)catalyst bed (2) pre-heating part (3)heater (4) thermal insulation material (5) thermocouples
Figure 3. (a) Cross section photo of the EHAC; (b) Heatexchange reformer (HER); (c) Heat exchange
reformer coupled with preheating chamber(PHER).
(For clarity, the schemes are not drawn in a real scale).
Figure 6. (a) Velocity field surface and stream line
profilesin the PHER for (a-1) reforming chamber
and (a-2) combustion 1 preheating chambers;
(b) temperature distribution and contour profilesin the (b-1) reforming chamber and (b-2)
combustion 1 preheating chambers.
Figure 7. Transient profiles of the temperature distribution
(a) in the reforming chamber and (b) in
the combustion and preheating chamber with
3-min electrically heating.
Figure 8. (a) Ordinary heat exchange system of the
fuel processor26; (b) simplified heat
exchange system of the fuel processor.
AIChE Journal
2. Start-up performance of the reformer
Figure 5. Effects of the fuel ratio on the reforming performanceand heat point temperature for thePHER
As Fig7(a) shows that the temperatures are greatly higher at the locations near the heater while the temperature shows rather even distributions at different radius locations when by electrical heat-up through EHAC (Fig 7 (b)). Since it is obvious that even temperature distribution can improve the reaction performance, the inside heat-up is preferred in the catalytic reactor.
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