12

1st Reformers

2 (3-R-6-R-3)

Gas Flow

Counter Flow

Pressure

O.lMPa

Photo 1 Installation of AIR100-1

The initial performance as the average cell voltage is 0.791V at the current density=150mA/cm 2, when the fuel is the city gas (Japanese code:13A, natural gas) at the steam to carbon ratio=3, the fuel utilization is 80%, the oxidant is Aii/CO 2 =70/30 and the oxidant utilization is 30%. This value is higher than data of 0.5m 2 AIR stacks i.e. 0.78V at the maximum, so that the stack design which uses large cells is satisfactory. The individual cell voltages are shown in Fig. 4. The AIR100-1 stack has been operated stably since February 1996. The operation time is 3,410hours (the power generating time:3,211hours) and the total generated electric power is 39MWh on August 9, 1996. The voltage decay rate is about 5mV/l,000h up to now, including scheduled thermal cycle once.

. 4 Initial Performance of AIR100-1

Fig. 5 Temperature Distribution in the Cell Plane of AIR100-1

. 4 Initial Performance of AIR100-1

Fig. 5 Temperature Distribution in the Cell Plane of AIR100-1

A typical temperature distribution in the cell plane of AIR100-1 is shown in Fig. 5. The 1 dimensional temperature gradient is almost attained in the direction of the cathode gas flow. The inlet side of the cathode (the outlet side of the anode), where the temperature is relatively low, is utilized to elongate the catalyst life of the 2nd reformer. Furthermore, the cathode gas outlet temperature is the maximum so that it is easy to perform the temperature control of the stack and to recover the exhaust gas energy form the stack. The progress in the thermal design of IR stacks is shown in Fig. 6 and 7. This is the design concept to raise the average operating temperature, keeping the maximum temperature constant and also keeping the cathode gas flow rate decreasing.

-: AIR, tm1, Counter Row, ICkW, I2calls C95 Design)

------: AIR, 0.5m1, Cross Flow, 10kW, 20ce1ls 093 Design)

-: DIR, 0Jm!, Cross Flow, 30kW, 57ce1ls C92 Design)

-: AIR, tm1, Counter Row, ICkW, I2calls C95 Design)

------: AIR, 0.5m1, Cross Flow, 10kW, 20ce1ls 093 Design)

-: DIR, 0Jm!, Cross Flow, 30kW, 57ce1ls C92 Design)

520 540 560 580 600 620 640 660 680 700 TEMPERATURE [^D]

Fig. 6 Progress of Temperature Distributions of IR Stacks

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