MoistAirTab™ Example 6 - Air Dehydration
Ambient air at 85°F and 760 mm Hg and 55% relative humidity is compressed to 10 atm (gauge) to supply a requirement for 250 lb/hr of air (dry basis). The mixture is cooled in a condenser to remove 90% of the original moisture content. The air stream is further dehydrated to -10°F dew point (at the line pressure) in a desiccant dryer. The pressure drop in condenser and desiccant dryer is 5 psi each. The isentropic efficiency of the air compressor is 85%.
- To what temperature must the air stream be cooled in the condenser?
- How much water needs to be removed in the desiccant dryer?
The solution is presented below as a table generated from Excel. The gray shaded areas represent the input data.
|Solution:||Units||Ambient Air||Compressor Outlet||Condenser Outlet||Desiccant Dryer Outlet|
|Flow rate (dry air)||lbdry air/hr||250||250||250||250|
|Moisture removal||%|| || ||90%|| |
|Pressure||mm Hg||760|| || || |
| ||atm|| ||11|| || |
| ||psia||14.69 ||161.59||156.59||151.59|
|Releative humidity||%||55%|| ||100%|| |
|Dry bulb temperature||°F||85|| ||68.66|| |
|Dew point temperature||°F||67.04|| || ||-10|
|Humidity ratio||lbw/lbdry air||0.0143||0.0143||0.0014||4.64949E-05|
|Moisture flow||lbw/hr||3.568 || ||0.357 ||0.012 |
|Moisture removal||lbw/hr|| || ||3.211 ||0.345 |