The unit cooling loss decreases with the increase of device capacity, while the temperature difference at the hot end of large air separation equipment design is generally around 3 ℃, and the unit heat exchange incomplete loss of different devices does not change much. Therefore, as the device capacity increases, the proportion of incomplete heat exchange loss per unit in total cooling loss increases. The approximate proportion of incomplete heat exchange loss per unit to total cold loss for air separation equipment with different capacities is shown in the table:
The proportion of incomplete heat exchange losses in air separation equipment with different capacities
|
Device capacity/m3·h-1 |
1000 |
3200 |
6000 |
10000 |
20000 |
|
The proportion of incomplete heat exchange loss/% |
34.2 |
39.3 |
46.0 |
47.0 |
52.4 |
From the table, it can be seen that under a temperature difference of 3 ℃ at the hot end of a large capacity air separation equipment, the incomplete heat exchange loss accounts for about half of the total cold loss. If the temperature difference increases by 1 ℃, it will increase the total cooling loss by about 16%. In order to compensate for the increased cold loss, it is required to increase the expansion capacity of the expander, which will affect the operation of the entire device. Therefore, during operation, it is important for operators to pay attention to the changes in the temperature difference at the hot end, take corresponding measures to prevent the temperature difference from expanding, and avoid exceeding the design value.
