Nuclear Production of Hydrogen, Fourth Information Exchange ...

HEAT PUMP CYCLE BY HYDROGEN-ABSORBING ALLOYS TO ASSIST HTGR IN PRODUCING HYDROGEN
Figure 7: Experimental temperature jump and total H 2 absorption
amount of ZrV 1.9 Fe 0.1 alloy as a function of inlet temperature at bed
from the outside cylinder. When W < 5 L/min, the values of T max -T 0 increases with W. This is because
heat generation during hydrogenating is insufficient. On the other hand, when W > 5 L/min, T max -T 0 is
independent of W and a function of only T 0 . This is because heat released during hydrogenating is
efficiently transferred to hydrogen gas. In this experiment, the temperature jump of 100°C was
observed even at T 0 = 600°C. In addition, the temperature jump is in proportion to the total hydrogen
absorption amount of q 0 . This result implies that ZrV 1.9 Fe 0.1 can heat up coolant gas even at 600°C.
Therefore, it is proved that the high-temperature heat pump cycle is effectively operated under the
condition of HTGR.
Continuous H 2 desorption during heating
It is important for heat pump operation to observe whether hydrogen desorbs from the Zr-V-Fe alloy
with sufficiently fast rates or not. Figure 8 shows variations of the rate of hydrogen desorbed from the
ZrV 1.9 Fe 0.1 bed with time, after the bed has been saturated with hydrogen. Only temperature is controlled
in such a way where T-T 0 is in proportion to time. The hydrogen desorption rate is maintained almost
constant nevertheless. Consequently, it is proved that the present alloy can absorb and desorb
hydrogen with a controlled rate and heat can be supplied in the bed and extracted from it during
absorption and desorption.
Figure 8: H 2 desorption rate from ZrV 1.9 Fe 0.1 alloy by heating
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