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What proportion of the total refrigerating capacity of the expander in the low-pressure air separation unit

What proportion of the total refrigerating capacity of the expander in the low-pressure air separation unit
Mar 06, 2023
Author: DEAR AST

The working pressure of the full-low pressure air separation unit is about 0.6MPa, so the refrigeration capacity of throttling effect is very small. For each cubic meter of processing air, it is only 1.36kJ/m3.

However, for each cubic meter of processing air, the cooling loss of the device is 4.2~7.5 kJ/m3, and the incomplete heat exchange loss is about 3.9 kJ/m3 when the temperature difference at the hot end is 3 ℃. Therefore, for the air separation equipment that does not produce liquid products, the total cold loss is 8.1~11.4kJ/m3. It can be seen that the vast majority of the total cooling loss is compensated by the expander cooling. The required expander cooling capacity is 6.74~10.04kJ/m3, accounting for 83%~88% of the total cooling capacity. It is generally believed that under normal working conditions, the cooling capacity of the expansion mechanism accounts for about 85% - 90% of the total cooling capacity and the throttling effect accounts for 10% - 15% of the total cooling capacity.

When the device is started or some liquid products are produced, it will be compensated by increasing the refrigeration capacity of the expander, which will account for a larger proportion.

The technical team of DEAR Air Separation Engineering has experts and professional technical personnel who have been engaged in the construction of air separation engineering for a long time, and comprehensively uses the knowledge and experience of engineering technology to ensure that each link is implemented in place and handled carefully, so that customers can rest assured and satisfied.

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