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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