The following operating conditions must be considered in every project: inlet air pressure, ambient temperature, inlet air temperature and pressure dewpoint. Each operating parameter has a corresponding numerical factor. A simple calculation between the air flow rate and the various factors defines the right dryer model to choose.
Air flow capacity = Nominal duty x (Factor F1 x Factor F2 x Factor F3 x Factor F4)
| F1 | Pressure [barg] | 4 | 5 | 6 | 7 | 8 | 10 | 12 | 14 | 16 | |
| Correction Factor | 0.77 | 0.86 | 0.93 | 1.00 | 1.05 | 1.14 | 1.21 | 1.27 | 1.33 | ||
| F2 | Ambient Temp [°C] | ≤ 25 | 30 | 35 | 40 | 45 | 50 | ||||
| Correction Factor | 1.00 | 0.96 | 0.90 | 0.82 | 0.72 | 0.60 | |||||
| F3 | Inlet Temp [°C] | ≤ 25 | 30 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 |
| Correction Factor | 1.20 | 1.12 | 1.00 | 0.83 | 0.69 | 0.59 | 0.50 | 0.44 | 0.39 | 0.37 | |
| F4 | Dew Point [°C] | 3 | 5 | 7 | 10 | ||||||
| Correction Factor | 1.00 | 1.09 | 1.19 | 1.37 |
Example: A dryer has a nominal duty of 108 m3/h. What is the maximum allowable flow through the dryer under the following operating conditions?
Each item of data has a corresponding numerical factor which multiplied by the design air flow is as follows:
Air flow capacity = 108 x 1.05 x 0.72 x 0.59 x 1.37 = 66 m3/h
66 m3/h This is the maximum flow rate that the dryer can accept under these operating conditions.
Minimum std. air flow rate = Design air flow ÷ (Factor F1 x Factor F2 x Factor F3 x Factor F4)
Example: With the following operating parameters:
In order to select the correct dryer model the required flow rate is to be divided by the correction factors relating to above mentioned parameters:
Minimum standard air flow rate = 100 : (1.05 x 0.72 x 0.59 x 1.37) = 164 m3/h
Therefore a Friulair Dryer model suitable for the conditions above is FCT 30 (186 m3/h - nominal duty).
